Final Government Distribution Technical Summary IPCC AR6 WG III
1 Table of Contents
2
3 TS. 1 Introduction ........................................................................................................................ 3
4 TS. 2 The changed global context, signs of progress and continuing challenges ........................ 5
5 TS. 3 Emission trends and drivers.............................................................................................. 12
6 TS. 4 Mitigation and development pathways ............................................................................. 28
7 TS. 4.1 Mitigation and development pathways in the near- to mid-term ...................................... 28
8 TS. 4.2 Long-term mitigation pathways ........................................................................................ 39
9 TS. 5 Mitigation responses in sectors and systems .................................................................... 52
10 TS. 5.1 Energy ............................................................................................................................... 52
11 TS. 5.2 Urban and other settlements .............................................................................................. 61
12 TS. 5.3 Transport ........................................................................................................................... 67
13 TS. 5.4 Buildings ........................................................................................................................... 71
14 TS. 5.5 Industry ............................................................................................................................. 77
15 TS. 5.6 Agriculture, forestry and other land uses, and food systems ............................................ 84
16 TS. 5.6.1 AFOLU .................................................................................................................... 84
17 TS. 5.6.2 Food systems ............................................................................................................ 88
18 TS. 5.7 Carbon dioxide removal (CDR) ........................................................................................ 94
19 TS. 5.8 Demand-side aspects of mitigation ................................................................................... 98
20 TS. 5.9 Mitigation potential across sectors and systems ............................................................. 107
21 TS. 6 Implementation and enabling conditions........................................................................ 109
22 TS. 6.1 Policy and Institutions ..................................................................................................... 109
23 TS. 6.2 International cooperation ................................................................................................ 119
24 TS. 6.3 Societal aspects of mitigation ......................................................................................... 120
25 TS. 6.4 Investment and finance ................................................................................................... 122
26 TS. 6.5 Innovation, technology development and transfer .......................................................... 127
27 TS. 7 Mitigation in the context of sustainable development .................................................... 133
28
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Final Government Distribution Technical Summary IPCC AR6 WG III
1 TS. 1 Introduction
2 The Working Group III (WG III) contribution to the IPCC’s Sixth Assessment Report (AR6) assesses
3 the current state of knowledge on the scientific, technological, environmental, economic and social
4 aspects of climate change mitigation. It builds on previous IPCC reports, including the WG III
5 contribution to the IPCC’s Fifth Assessment Report (AR5) and the three Special Reports of the Sixth
6 Assessment cycle on: Global warming of 1.5°C (SR 1.5°C); Climate Change and Land (SRCCL); and,
7 the Ocean and Cryosphere in a Changing Climate (SROCC).1
8 The report assesses new literature, methodological and recent developments, and changes in approaches
9 towards climate change mitigation since the IPCC AR5 report was published in 2014.
10 The global science and policy landscape on climate change mitigation has evolved since AR5. The
11 development of the literature reflects, among other factors, the UN Framework Convention on Climate
12 Change (UNFCCC), the outcomes of its Kyoto Protocol and the goals of the Paris Agreement {13, 14,
13 15}, and the UN 2030 Agenda for Sustainable Development {1, 4, 17}. Literature further highlights the
14 growing role of non-state and sub-national actors in the global effort to address climate change,
15 including cities, businesses, citizens, transnational initiatives and public-private entities {5, 8, 13}. It
16 draws attention to the decreasing cost of some low emission technologies {2, 6, 12} and the evolving
17 role of international cooperation {14}, finance {15} and innovation {16}. Emerging literature examines
18 the global spread of climate policies, strengthened mitigation actions in developing countries, sustained
19 reductions in greenhouse gas (GHG) emissions in some developed countries and the continuing
20 challenges for mitigation. {2, 13}
21 There are ever closer linkages between climate change mitigation, development pathways and the
22 pursuit of sustainable development goals. Development pathways largely drive GHG emissions and
23 hence shape the mitigation challenge and the portfolio of available responses {4}. The co-benefits and
24 risks of mitigation responses also differ according to stages of development and national capabilities
25 {1, 2, 3, 4, 13}. Climate change mitigation framed in the context of sustainable development, equity,
26 and poverty eradication, and rooted in the development aspirations of the society within which they
27 take place, will be more acceptable, durable and effective. {1, 4, 17}
28 This report includes new assessment approaches that go beyond those evaluated in the previous IPCC
29 WG III reports. In addition to sectoral and systems chapters {6, 7, 8, 9, 10, 11}, this report includes, for
30 the first time, chapters dedicated to cross-sectoral perspectives {12} demand, services and social aspects
31 of mitigation (Box TS.11) {5} and innovation, technology development and transfer {16}. The
32 assessment of future pathways combines a forward-looking assessment of near- to medium-term
33 perspectives up to 2050, including ways of shifting development pathways towards sustainability {4},
34 with an assessment of long-term outcome-oriented pathways up to 2100 {3}. Collaboration between
35 the IPCC Working Groups is reflected in Cross-Working Group boxes which address topics such as the
36 economic benefits from avoided impacts along mitigation pathways {Cross-Working Group Box 1 in
37 Chapter 3}, climate change and urban areas {Cross-Working Group Box 2 in Chapter 8}, mitigation
38 and adaptation through the bioeconomy {Cross-Working Group Box 3 in Chapter 12} and Solar
39 Radiation Modification {Cross-Working Group Box 4 in Chapter 14}. This assessment also gives
FOOTNOTE 1 The three Special Reports are: Global Warming of 1.5°C: an IPCC Special Report on the impacts
of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in
the context of strengthening the global response to the threat of climate change, sustainable development, and
efforts to eradicate poverty (2018); Climate Change and Land: an IPCC Special Report on climate change,
desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in
terrestrial ecosystems (2019); IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (2019).
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Final Government Distribution Technical Summary IPCC AR6 WG III
1 greater attention than AR5 to social, economic and environmental dimensions of mitigation actions,
2 and institutional, legal and financial aspects {5, 13, 14, 15}.
3 The report draws from literature on broad and diverse analytic frameworks across multiple disciplines.
4 These include, inter alia: economic and environmental efficiency {1}; ethics and equity {4, 5, 17};
5 innovation and the dynamics of socio-technical transitions {16}; and, socio-political-institutional
6 frameworks {1, 5, 13, 14, 17}. These help to identify synergies and trade-offs with sustainable
7 development goals, challenges and windows of opportunity for action including co-benefits, and
8 equitable transitions at local, national and global scales. {1, 5, 13, 14, 16}.
9 This Technical Summary (TS) of the WG III contribution to the IPCC’s Sixth Assessment Report
10 broadly follows the report chapter order and is structured as follows.
11 • TS Section 2 sets out how the global context for mitigation has changed and summarises signs of
12 progress and continuing challenges.
13 • TS Section 3 evaluates emission trends and drivers including recent sectoral, financial,
14 technological and policy developments.
15 • TS Section 4 identifies mitigation and development pathways in the near and medium- term to
16 2050, and in the longer term to 2100. This section includes an assessment of how mitigation
17 pathways deploying different portfolios of mitigation responses are consistent with limiting global
18 warming to different levels.
19 • TS Section 5 summarises recent advances in knowledge across sectors and systems including
20 energy, urban and other settlements, transport, buildings, industry, and agriculture, forestry and
21 other land use.
22 • TS Section 6 examines how enabling conditions including behaviour and lifestyle, policy,
23 governance and institutional capacity, international cooperation, finance, and innovation and
24 technology can accelerate mitigation in the context of sustainable development
25 • TS Section 7 evaluates how mitigation can be achieved in the context of sustainable development,
26 while maximising co-benefits and minimising risks.
27
28 Throughout this Technical Summary the validity of findings, confidence in findings, and cross
29 references to Technical Summary sections, figures and tables are shown in ( ) brackets.2 References to
30 the underlying report are shown in { } brackets.
31
32
FOOTNOTE 2 Each finding is grounded in an evaluation of the underlying evidence, typeset in italics. The validity
of a finding is evaluated in terms of the evidence quality – ‘limited’, ‘medium’, ‘robust’ – and the degree of
agreement between sources – ‘low’, ‘medium’, ‘high’. A level of confidence is expressed using five qualifiers:
very low, low, medium, high and very high. Generally, the level of confidence is highest where there is robust
evidence from multiple sources and high agreement. For findings with, for example, ‘robust evidence, medium
agreement’, a confidence statement may not always be appropriate. The assessed likelihood of an outcome or a
result is described as: virtually certain 99–100% probability, very likely 90–100%, likely 66–100%, about as likely
as not 33–66%, unlikely 0–33%, very unlikely 0–10%, exceptionally unlikely 0–1%. Additional terms may also
be used when appropriate, consistent with the IPCC uncertainty guidance:
https://www.ipcc.ch/site/assets/uploads/2018/05/uncertainty-guidance-note.pdf.
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1 TS. 2 The changed global context, signs of progress and continuing
2 challenges
3 Since the IPCC’s Fifth Assessment Report (AR5), important changes that have emerged include
4 the specific objectives established in the Paris Agreement of 2015 (for temperature, adaptation
5 and finance), rising climate impacts, and higher levels of societal awareness and support for
6 climate action (high confidence). Meeting the long-term temperature goal in the Paris Agreement,
7 however, implies a rapid inflection in GHG emission trends and accelerating decline towards ‘net zero’.
8 This is implausible without urgent and ambitious action at all scales. {1.2, 1.3, 1.5, 1.6, Chapters 3 and
9 4}
10 Effective and equitable climate policies are largely compatible with the broader goal of
11 sustainable development and efforts to eradicate poverty as enshrined in the UN 2030 Agenda for
12 Sustainable Development and its 17 Sustainable Development Goals (SDGs), notwithstanding
13 trade-offs in some cases (high confidence). Taking urgent action to combat climate change and its
14 impacts is one of the 17 SDGs (SDG13). However, climate change mitigation also has synergies and/or
15 trade-offs with many other SDGs. There has been a strong relationship between development and GHG
16 emissions, as historically both per capita and absolute emissions have risen with industrialisation.
17 However, recent evidence shows countries can grow their economies while reducing emissions.
18 Countries have different priorities in achieving the SDGs and reducing emissions as informed by their
19 respective national conditions and capabilities. Given the differences in GHG emissions contributions,
20 degree of vulnerability and impacts, as well as capacities within and between nations, equity and justice
21 are important considerations for effective climate policy and for securing national and international
22 support for deep decarbonisation. Achieving sustainable development and eradicating poverty would
23 involve effective and equitable climate policies at all levels from local to global scale. Failure to address
24 questions of equity and justice over time can undermine social cohesion and stability. International co-
25 operation can enhance efforts to achieve ambitious global climate mitigation in the context of
26 sustainable development pathways towards fulfilling the SDGs are illustrated in Figure TS.1. {1.4, 1.6,
27 Chapters 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13 and 17}
28
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1
2
3 Figure TS.1: Sustainable development pathways towards fulfilling the Sustainable Development Goals
4 Figure TS.1 legend: The graph shows how global average per capita GHG emissions (vertical axis) and relative
5 "Historic Index of Human Development" (HIHD) levels (horizonal axis) have increased globally since the
6 industrial revolution (grey line). The bubbles on the graph show regional per capita GHG emissions and human
7 development levels in the year 2015, illustrating large disparities. Pathways towards fulfilling the Paris
8 Agreement and SDG 13 (Climate Action) involve global average per capita GHG emissions below around 5
9 tCO2eq by 2030. Likewise, HIHD levels need to be at least 0.5 or greater to fulfil SDGs 3 (Good Health &
10 Well-being), SDG 4 (Quality Education) and SDG 8 (Decent Work & Economic Growth). This suggests a
11 ‘sustainable development zone’ for year 2030 (in green); the in-figure text also suggests a sustainable
12 development corridor, where countries limit per capita GHG emissions while improving levels of human
13 development over time. The emphasis of pathways into the sustainable development zone differ (green arrows)
14 but in each case transformations are needed in how human development is attained while limiting GHG
15 emissions. {Figure 1.6}
16
17 The transition to a low carbon economy depends on a wide range of closely intertwined drivers
18 and constraints, including policies and technologies where notable advances over the past decade
19 have opened up new and large-scale opportunities for deep decarbonisation, and for alternative
20 development pathways which could deliver multiple social and developmental goals (high
21 confidence). Drivers for-, and constraints on-, low carbon societal transitions comprise economic and
22 technological factors (the means by which services such as food, heating and shelter are provided and
23 for whom, the emissions intensity of traded products, finance and investment), socio-political issues
24 (political economy, equity and fairness, social innovation and behaviour change), and institutional
25 factors (legal framework and institutions, and the quality of international cooperation). In addition to
26 being deeply intertwined, all the factors matter to varying degrees, depending on prevailing social,
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1 economic, cultural and political context. They often both drive and inhibit transitions at the same time,
2 within and across different scales. The development and deployment of innovative technologies and
3 systems at scale are important for achieving deep decarbonisation, and in recent years, the cost of
4 several low carbon technologies has declined sharply as deployment has risen rapidly. (Figure TS.7)
5 {1.3, 1.4, Chapters 2, 4, 5, 13,14}
6 Accelerating mitigation to prevent dangerous anthropogenic interference with the climate system
7 will require the integration of broadened assessment frameworks and tools that combine multiple
8 perspectives, applied in a context of multi-level governance (high confidence). Analysing a
9 challenge on the scale of fully decarbonising our economies entails integration of multiple analytic
10 frameworks. Approaches to risk assessment and resilience, established across IPCC Working Groups,
11 are complemented by frameworks for probing the challenges in implementing mitigation. Aggregate
12 frameworks include cost-effectiveness analysis towards given objectives, and cost-benefit analysis,
13 both of which have been developing to take fuller account of advances in understanding risks and
14 innovation, the dynamics of sectors and systems and of climate impacts, and welfare economic theory
15 including growing consensus on long-term discounting. Ethical frameworks consider the fairness of
16 processes and outcomes which can help ameliorate distributional impacts across income groups,
17 countries and generations. Transition and transformation frameworks explain and evaluate the
18 dynamics of transitions to low-carbon systems arising from interactions amongst levels. Psychological,
19 behavioural and political frameworks outline the constraints (and opportunities) arising from human
20 psychology and the power of incumbent interests. A comprehensive understanding of climate mitigation
21 must combine these multiple frameworks. Together with established risk frameworks, these collectively
22 help to explain potential synergies and trade-offs in mitigation, implying a need for a wide portfolio of
23 policies attuned to different actors and levels of decision-making, and underpin ‘just transition’
24 strategies in diverse contexts. {1.2.2, 1.7, 1.8, Figure 1.7}
25 The speed, direction, and depth of any transition will be determined by choices in the
26 environmental, technological, economic, socio-cultural and institutional realms (high confidence).
27 Transitions in specific systems can be gradual or can be rapid and disruptive. The pace of a transition
28 can be impeded by ‘lock-in’ generated by existing physical capital, institutions, and social norms. The
29 interaction between politics, economics and power relationships is central to explaining why broad
30 commitments do not always translate to urgent action. At the same time, attention to, and support for,
31 climate policies and low carbon societal transitions has generally increased, as the impacts have become
32 more salient. Both public and private financing and financial structures strongly affect the scale and
33 balance of high and low carbon investments. Societal and behavioural norms, regulations and
34 institutions are essential conditions to accelerate low carbon transitions in multiple sectors, whilst
35 addressing distributional concerns endemic to any major transition. The COVID-19 pandemic has also
36 had far-reaching impacts on the global economic and social system, and recovery will present both
37 challenges and opportunities for climate mitigation. (Box TS.1){1.3, Box 1.1, 1.4, 1.8, Chapters 2, 3, 4,
38 5, 15, 17}
39 Achieving the global transition to a low-carbon, climate-resilient and sustainable world requires
40 purposeful and increasingly coordinated planning and decisions at many scales of governance
41 including local, subnational, national and global levels (high confidence). Accelerating mitigation
42 globally would imply strengthening policies adopted to date, expanding the effort across options,
43 sectors, and countries, and broadening responses to include more diverse actors and societal processes
44 at multiple – including international – levels. The effective governance of climate change entails strong
45 action across multiple jurisdictions and decision-making levels, including regular evaluation and
46 learning. Choices that cause climate change as well as the processes for making and implementing
47 relevant decisions involve a range of non-nation state actors such as cities, businesses, and civil society
48 organisations. At global, national and subnational levels, climate change actions are interwoven with,
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1 and embedded in, the context of much broader social, economic and political goals. Therefore, the
2 governance required to address climate change has to navigate power, political, economic, and social
3 dynamics at all levels of decision making. Effective climate-governing institutions, and openness to
4 experimentation on a variety of institutional arrangements, policies and programmes can play a vital
5 role in engaging stakeholders and building momentum for effective climate action. {1.4, 1.9, Chapters
6 8, 13, 15, 17}
7 GHG emissions continued to rise to 2019, although the growth of global GHG emissions has
8 slowed over the past decade (high confidence). Delivering the updated Nationally Determined
9 Contributions (NDCs) to 2030 would turn this into decline, but the implied global emissions by 2030,
10 still exceed pathways consistent with 1.5°C by a large margin and are near the upper end of the range
11 of modelled pathways that likely limit warming to 2°C or below. In all chapters of this report there is
12 evidence of progress towards deeper mitigation, but there remain many obstacles to be overcome. Table
13 TS.1 summarises some of the key signs of progress in emission trends, sectors, policies and investment,
14 as well as the challenges that persist.
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1 Table TS.1: Signs of Progress and Continuing Challenges
Signs of progress Continuing challenges
Emissions trends
The rate of global GHG emissions growth has slowed in recent years, from 2.1% GHG emissions have continued to grow at high absolute rates. Emissions
per year between 2000 and 2009, to 1.3% per year in between 2010 and 2019. (TS.3) increased by 8.9 GtCO2eq from 2000-2009 and by 6.5 GtCO2eq 2010-2019,
{2.2} reaching 59 GtCO2eq in 2019. (TS.3) {2.2}
At least 24 countries have reduced both territorial carbon dioxide (CO2) and The combined emissions reductions of these 24 countries were outweighed by
GHG emissions and consumption-based CO2 emissions in absolute terms for at rapid emissions growth elsewhere, particularly among developing countries that
least 10 years, including consumption-based CO2 emissions. Of these, six are have grown from a much lower base of per capita emissions. Uncertainties in
Western and Northern European countries that started reducing in the 1970s, six are emissions levels and changes over time prevents a precise assessment of reductions
former Eastern Bloc countries with consistent reductions since the 1990s, and 12 in some cases. The per capita emissions of developed countries remain high,
more have reduced since the mid-2000s. Some have done so at rapid sustained CO2 particularly in Australia, Canada, and the United States. {2.2}
reduction rates of 4% per year. (TS.3) {2.2}
Lockdown policies in response to COVID-19 led to an estimated global drop of Atmospheric CO2 concentrations continued to rise in 2020 and emissions have
5.8% in CO2 emissions in 2020 relative to 2019. Energy demand reduction occurred already rebounded as lockdown policies are eased. Economic recovery packages
across sectors, except in residential buildings due to teleworking and homeschooling. currently include support for fossil fuel industries. (Box TS.1; Box TS.8)
The transport sector was particularly impacted and international aviation emissions
declined by 45%. (Box TS.1) {2.2}
Sectors
Multiple low-carbon electricity generation and storage technologies have made Although deployment is increasing rapidly, low-carbon electricity generation
rapid progress: costs have reduced, deployment has scaled up, and performance deployment levels and rates are currently insufficient to meet stringent climate
has improved. These include solar photovoltaics (PV), onshore and offshore wind, goals. The combined market share of solar PV and wind generation technologies are
and batteries. In many contexts solar PV and onshore wind power are now still below 10%. Global low-carbon electricity generation will have to reach 100%
competitive with fossil-based generation. (TS.3) {2.5, 6.3} by 2050, which is challenged by the continuous global increase in electricity
demand. The contribution of biomass has absolute limits. (TS.5, 2.5)
The rate of emissions growth from coal slowed since 2010 as coal power plants Global coal emissions may not have peaked yet, and a few countries and
were retired in the United States and Europe, fewer new plants were added in China, international development banks continue to fund and develop new coal capacity,
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Signs of progress Continuing challenges
and a large number of planned global plants were scrapped or converted to co-firing especially abroad. The lifetime emissions of current fossil-based energy
with biomass. (TS.3) {2.7, 6.3} infrastructures may already exceed the remaining carbon budget for keeping
warming below 1.5°C. (TS.3) {2.2; 2.7, 6.7}
Deforestation has declined since 2010 and net forest cover increased. The long-term maintenance of low deforestation rates is challenging.
Government initiatives and international moratoria were successful in reducing Deforestation in the Amazon has risen again over the past four years. Other parts of
deforestation in the Amazon between 2004 and 2015, while regrowth and the world also face steady, or rapidly increasing, deforestation. {7.3.1}
regeneration occurred in Europe, Eurasia and North America. (TS.5.6.1) {7.3.1}
Electrification of public transport services is demonstrated as a feasible, scalable Transport emissions have remained roughly constant, growing at an average
and affordable mitigation option to decarbonise mass transportation. Electric of 2% per annum between 2010-2019 due to the persistence of high travel demand,
vehicles (e-vehicles) are the fastest growing segment of the automobile industry, heavier vehicles, low efficiencies, and car-centric development. The full
having achieved double-digit market share by 2020 in many countries. When decarbonisation of e-vehicles requires that they are charged with zero-carbon
charged with low-carbon electricity, these vehicles can significantly reduce electricity, and that car production, shipping, aviation and supply chains are
emissions. {10.4} decarbonized. (TS.3) {2.4}
There has been a significant global transition from coal and biomass use in There is a significant lock-in risk in all regions given the long lifespans of
buildings towards modern energy carriers and efficient conversion technologies. buildings and the low ambition of building policies. This is the case for both
This led to efficiency improvements and some emissions reductions in developed existing buildings in developed countries, and also for new buildings in developing
countries, as well as significant gains in health and well-being outcomes in countries that are also challenged by the lack of technical capacity and effective
developing regions. Nearly Zero Energy (NZE) Buildings or low-energy Buildings governance. Emissions reductions in developed countries have been outweighed by
are achievable in all regions and climate zones for both new and existing buildings. the increase in population growth, floor area per capita and the demand for electricity
{9.3; 9.8} and heat. {9.9; 9.3}
The decarbonisation of most industrial processes has been demonstrated using Industry emissions continue to increase, driven by a strong global demand for
technologies that include electricity and hydrogen for energy and feedstocks, carbon basic materials. Without reductions in material demand growth and a very rapid
capture and utilisation technologies, and innovation in circular material flows. scale-up of low-carbon innovations, the long lifetimes of industrial capital stock
(TS.5.5) {11.2} risks locking-in emissions for decades to come. (TS.5.5) {11.2}
Policies and investment
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Signs of progress Continuing challenges
The Paris Agreement established a new global policy architecture to meet Current national pledges under the Paris Agreement3 are insufficient to limit
stringent climate goals, while avoiding many areas of deadlock that had arisen in warming to 1.5°C with no or limited overshoot, and would require an abrupt
trying to extend the Kyoto Protocol. (TS 6.3) acceleration of mitigation efforts after 2030 to likely limit warming to 2°C. (TS
6.3)
Most wealthy countries, and a growing list of developing countries, have Many net zero targets are ambiguously defined, and the policies needed to
signaled an intention to achieve net zero GHG (or net zero CO2) emissions by achieve them are not yet in place. Opposition from status quo interests, as well as
mid-century. National economy-wide GHG emissions targets covered 90% of insufficient low-carbon financial flows, act as barriers to establishing and
global emissions in 2020 compared to 49% in 2010. Direct and indirect climate implementing stringent climate policies covering all sectors. (Box TS.6) {13.4}
legislation has also steadily increased and this is supported by a growing list of
financial investors. (TS.6.2)
The global coverage of mandatory policies – pricing and regulation – has There is incomplete global policy coverage of non-CO2 gases, CO2 from
increased, and sectoral coverage of mitigation policies has expanded. Emission industrial processes, and emissions outside the energy sector. Few of the world’s
trading and carbon taxes now cover over 20% of global CO2 emissions (TS 6). carbon prices are at a level consistent with various estimates of the carbon price
Allowance prices as of April 1, 2021 ranged from just over USD1 to USD50, needed to limit warming to 2°C or 1.5°C {13.6}
covering between 9 and 80% of a jurisdiction’s emissions {13.6.3}. Many countries
have introduced sectoral regulations that block new investment in fossil fuel
technologies.
There has been a marked increase in civic and private engagement with climate There is no conclusive evidence that an increase in engagement results in
governance. This includes business measures to limit emissions, invest in overall pro-mitigation outcomes. A broad group of actors influence how climate
reforestation and develop carbon-neutral value chains such as using wood for governance develop over time, including a range of civic organisations,
construction. There is an upsurge in climate activism, and growing engagement of encompassing both pro-and anti-climate action groups. Accurate transference of the
groups such as labour unions {1.3.3, 5.2.3}. The media coverage of climate change climate science has been undermined significantly by climate change counter-
has also grown steadily across platforms and has generally become more accurate movements, in both legacy and new/social media environments through
over time. (TS 6.2) misinformation. (TS 6.2)
1
FOOTNOTE 3 Current NDCs refer to nationally determined contributions submitted to the UNFCCC, as well as publicly announced but not yet submitted mitigation pledges
with sufficient detail on targets, reflected in studies published up to 11 October 2021. Revised NDCs submitted or announced after 11 October 2021 are not included. Intended
nationally determined contributions (INDCs) were converted to NDCs as countries ratified the Paris Agreement. Original INDCs and NDCs refer to those submitted to the
UNFCCC in 2015 and 2016
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1 TS. 3 Emission trends and drivers
2 Global net anthropogenic GHG emissions during the decade (2010-2019) were higher than any
3 previous time in human history (high confidence). Since 2010, GHG emissions have continued to
4 grow reaching 59±6.6 GtCO2-eq in 2019,4 but the average annual growth in the last decade (1.3%,
5 2010-2019) was lower than in the previous decade (2.1%, 2000-2009) (high confidence). Average
6 annual GHG emissions were 56 GtCO2-eq yr-1 for 2010-2019 (the highest decadal average on record)
7 growing by about 9.1 GtCO2-eq yr-1 from the previous decade (2000-2009) (high confidence). (Figure
8 TS.2) {2.2.2, Table 2.1, Figure 2.5}
9 Emissions growth has varied, but has persisted, across all groups of greenhouse gases (high
10 confidence). The average annual emission levels of the last decade (2010-2019) were higher than in
11 any previous decade for each group of greenhouse gases (high confidence). In 2019, CO2 emissions
12 were 45±5.5 GtCO2,5 methane (CH4) 11±3.2 GtCO2-eq, nitrous oxide (N2O) 2.7±1.6 GtCO2-eq and
13 fluorinated gases (F-gases6) 1.4±0.41 GtCO2-eq. Compared to 1990, the magnitude and speed of these
14 increases differed across gases: CO2 from fossil fuel and industry (FFI) grew by 15 GtCO2-eq yr-1
15 (67%), CH4 by 2.4 GtCO2-eq yr-1 (29%), F-gases by 0.97 GtCO2-eq yr-1 (250%), N2O by 0.65 GtCO2-
16 eq yr-1 (33%). CO2 emissions from net land use, land-use change and forestry (LULUCF) have shown
17 little long-term change, with large uncertainties preventing the detection of statistically significant
18 trends. F-gases excluded from GHG emissions inventories such as chlorofluorocarbons and
19 hydrochlorofluorocarbons are about the same size as those included (high confidence). (Figure TS.2)
20 {2.2.1, 2.2.2, Table 2.1, Figure 2.2, Figure 2.3, Figure 2.5}
21 Globally, Gross Domestic Product (GDP) per capita and population growth remained the
22 strongest drivers of CO2 emissions from fossil fuel combustion in the last decade (high confidence).
23 Trends since 1990 continued in the years 2010 to 2019 with GDP per capita and population growth
24 increasing emissions by 2.3% and 1.2% yr-1, respectively. This growth outpaced the reduction in the
25 use of energy per unit of GDP (-2% yr-1, globally) as well as improvements in the carbon intensity of
26 energy (-0.3% yr-1). {2.4.1, Figure 2.19}
27
FOOTNOTE 4 Emissions of GHGs are weighed by Global Warming Potentials with a 100 year time horizon
(GWP100) from the Sixth Assessment Report. GWP100 is commonly used in wide parts of the literature on
climate change mitigation and is required for reporting emissions under the United Nations Framework
Convention on Climate Change (UNFCCC). All metrics have limitations and uncertainties. {Cross-Chapter Box
2, Annex II Part II Section 8}
FOOTNOTE 5 In 2019, CO2 from fossil fuel and industry (FFI) were 38±3.0 Gt, CO2 from net land use, land-use
change and forestry (LULUCF) 6.6±4.6 Gt.
FOOTNOTE 6 Fluorinated gases, also known as ‘F-gases’, include: hydrofluorocarbons (HFCs), perfluorocarbons
(PFCs), sulphur hexafluouride (SF6), nitrogen trifluouride (NF3).
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1
2
3 Figure TS.2: Global anthropogenic emissions have continued to rise across all major groups of greenhouse gases (GtCO2-eq yr-1) 1990-2019
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1 Figure TS.2 Legend: Total anthropogenic GHG emissions include CO2 from fossil fuel combustion and
2 industrial processes (CO2-FFI); CO2 from Land use, land use change and forestry (CO2-LULUCF); methane
3 (CH4); nitrous oxide (N2O); fluorinated gases (F-gases: HFCs; PFCs, SF6, NF3). CO2-LULUCF emissions
4 include gross removals as well as emissions. F-gas emissions do not include some important species covered by
5 the Montreal Protocol such as (chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs).
6 Panel a: Aggregate GHG emission trends by groups of gases reported in GtCO 2-eq converted based on global
7 warming potentials with a 100-year time horizon (GWP100) from the IPCC Sixth Assessment Report Working
8 Group I (Chapter 7).
9 Panel b: GHG emissions for the year 2019 in Gt of CO2-eq units using GWP100 values from the IPCC’s Sixth,
10 Fifth and Second Assessment Reports, respectively. Error bars show emissions uncertainties at a 90%
11 confidence interval.
12 Panel c: Individual trends in CO2-FFI, CO2-LULUCF, CH4, N2O and F-gas emissions for the period 1990–2019,
13 normalised relative to 1 in 1990. Note the different scale for F-gas emissions compared to other gases,
14 highlighting its rapid growth from a low base. The table shows absolute emissions in 2019 as well as emissions
15 growth between 1990 and 2019, expressed as absolute change in CO 2-eq and as percentage change relative to
16 1990. Note that these changes therefore include interannual variability for these individual years as well as
17 longer term trends. {2.2, Figure 2.5}
18
19 START BOX TS.1 HERE
20 Box TS.1: The COVID-19 pandemic: Impact on emissions and opportunities for mitigation
21 The COVID-19 pandemic triggered the deepest global economic contraction as well as CO2 emission
22 reductions since the Second World War {2.2.2}. While emissions and most economies rebounded in
23 2020, some impacts of the pandemic could last well beyond this. Owing to the very recent nature of this
24 event, it remains unclear what the exact short and long-term impacts on global emissions drivers, trends,
25 macroeconomics and finance will be.
26 Starting in the spring of 2020 a major break in global emissions trends was observed due to lockdown
27 policies implemented in response to the pandemic. Overall, global CO2-FFI emissions are estimated to
28 have declined by 5.8% (5.1%-6.3%) in 2020, or about 2.2 (1.9-2.4) GtCO2 in total. This exceeds any
29 previous global emissions decline since 1970 both in relative and absolute terms (Box TS.1 Figure 1).
30 During periods of economic lockdown, daily emissions, estimated based on activity and power-
31 generation data, declined substantially compared to 2019, particularly in April 2020 –as shown in Box
32 TS.1 Figure 1 – but rebounded by the end of 2020. Impacts were differentiated by sector, with road
33 transport and aviation particularly affected. Different databases estimate the total power sector CO2
34 reduction from 2019 to 2020 at 3% (IEA7) and 4.5% (EDGAR8). Approaches that predict near real-time
35 estimates of the power sector reduction are more uncertain and estimates range more widely between
36 1.8%, 4.1% and 6.8%, the latter taking into account the over-proportional reduction of coal generation
37 due to low gas prices and merit order effects.
38
FOOTNOTE 7 IEA: International Energy Agency
FOOTNOTE 8 EDGAR: Emissions Database for Global Atmospheric Research
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1
2 Box TS.1 Figure 1: Global carbon emissions in 2020 and the impact of COVID-19
3 Box TS.1 Figure 1 legend: Panel a depicts carbon emissions from fossil fuel and industry over the past five
4 decades. The single year declines in emissions following major economic and geopolitical events are shown, as
5 well as the decline recorded in five different datasets for emissions in 2020 compared to 2019. Panel b depicts
6 the perturbation of daily carbon emissions in 2020 compared to 2019, showing the impact of COVID-19
7 lockdown policies. {Figure 2.6}
8 The lockdowns implemented in many countries accelerated some specific trends, such as the uptake in
9 urban cycling. The acceptability of collective social change over a longer term towards less resource-
10 intensive lifestyles, however, depends on the social mandate for change. This mandate can be built
11 through public participation, discussion and debate, to produce recommendations that inform
12 policymaking. {Box 5.2}
13 Most countries were forced to undertake unprecedented levels of short-term public expenditures in
14 2021. This is expected to slow economic growth and may squeeze financial resources for mitigation
15 and relevant investments in the near future. Pandemic responses have increased sovereign debt across
16 countries in all income bands and the sharp increase in most developing economies and regions has
17 caused debt distress, widening the gap in developing countries’ access to capital. {15.6.3}
18 The wider overall reduction in energy investment has prompted a relative shift towards low carbon
19 investment particularly for major future investment decisions by the private sector {15.2.1, 15.3.1,
20 15.6.1}. Some countries and regions have prioritised green stimulus expenditures for example as part
21 of a ‘Green New Deal’ {Box 13.1}. This is motivated by assessments that investing in new growth
22 industries can boost the macroeconomic effectiveness (‘multipliers’) of public spending, crowd-in and
23 revive private investment, whilst also delivering on mitigation commitments. {15.2.3}
24 The impacts of COVID-19 may have temporarily set back development and the delivery of many SDGs.
25 It also distracts political and financial capacity away from efforts to accelerate climate change
26 mitigation and shift development pathways to increased sustainability. Yet, studies of previous post-
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1 shock periods suggest that waves of innovation that are ready to emerge can be accelerated by crises,
2 which may prompt new behaviours, weaken incumbent systems, and initiate rapid reform. {1.6.5}
3 Institutional change can be slow but major economic dislocation can create significant opportunities for
4 new ways of financing and enabling ‘leapfrogging’ investment {10.8}. Given the unambiguous risks of
5 climate change, and consequent stranded asset risks from new fossil fuel investments {Box 6.11}, the
6 most robust recoveries may well be those which align with lower carbon and resilient development
7 pathways.
8 END BOX TS.1 HERE
9
10 Cumulative net CO2 emissions over the last decade (2010-2019) are about the same size as the
11 remaining carbon budget likely to limit warming to 1.5°C (medium confidence). 62% of total
12 cumulative CO2 emissions from 1850 to 2019 occurred since 1970 (1500±140 GtCO2), about 43% since
13 1990 (1000±90 GtCO2), and about 17% since 2010 (410±30 GtCO2). For comparison, the remaining
14 carbon budget for keeping warming to 1.5°C with a 67% (50%) probability is about 400 (500) ±220
15 GtCO2 (Figure TS.3). {2.2.2, Figure 2.7, WG I Chapter 5.5, WG I Chapter 5 Table 5.8}
16
17 Figure TS.3: Historic anthropogenic CO2 emission and cumulative CO2 emissions (1850-2019) as well as
18 remaining carbon budgets for likely limiting warming to 1.5°C and 2°C
19 Figure TS.3 legend: Panel a shows historic annual anthropogenic CO2 emissions (GtCO2 yr-1) by fuel type and
20 process. Panel b shows historic cumulative anthropogenic CO 2 emissions for the periods 1850-1989, 1990-2009,
21 and 2010-2019 as well as remaining future carbon budgets as of 1 January 2020 to limit warming to 1.5°C and
22 2°C at the 67th percentile of the transient climate response to cumulative CO 2 emissions. The whiskers indicate
23 a budget uncertainty of ±220 GtCO2-eq for each budget and the aggregate uncertainty range at one standard
24 deviation for historical cumulative CO2 emissions, consistent with Working Group I. {Figure 2.7}
25
26 A growing number of countries have achieved GHG emission reductions over periods longer than
27 10 years – a few at rates that are broadly consistent with the global rates described in climate
28 change mitigation scenarios that likely to limit warming to 2°C (high confidence). At least 24
29 countries have reduced CO2 and GHG emissions for longer than 10 years. Reduction rates in a few
30 countries have reached 4% in some years, in line with global rates observed in pathways that likely limit
31 warming to 2°C. However, the total reduction in annual GHG emissions of these countries is small
32 (about 3.2 GtCO2-eq yr-1) compared to global emissions growth observed over the last decades.
33 Complementary evidence suggests that countries have decoupled territorial CO2 emissions from GDP,
34 but fewer have decoupled consumption-based emissions from GDP. Decoupling has mostly occurred
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1 in countries with high per capita GDP and high per capita CO2 emissions. (Figure TS.4, Box TS.2)
2 {2.2.3, 2.3.3, Figure 2.11, Table 2.3, Table 2.4}
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1
2
3 Figure TS.4: Emissions have grown in most regions, although some countries have achieved sustained emission reductions in line with 2°C scenarios
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1
2 Figure TS.4 legend: Change in regional GHG emissions and rates of change compatible with warming targets.
3 Panel a: Regional GHG emission trends (in GtCO2-eq yr-1 (GWP100 AR6)) for the time period 1990–2019.
4 Panel b: Historical GHG emissions change by region (2010–2019). Circles depict countries, scaled by total
5 emissions in 2019, short horizontal lines depict the average change by region. Also shown are global rates of
6 reduction over the period 2020-2040 in scenarios assessed in the AR6 that limit global warming to 1.5°C and
7 2°C with different probabilities. The 5th –95th percentile range of emissions changes for scenarios below 1.5°C
8 with no or limited overshoot (scenario category C1) and scenarios likely below 2°C with immediate action
9 (scenario category C3a) are shown as a shaded area with a horizontal line at the mean value. Panel b excludes
10 CO2 LULUCF due to a lack of consistent historical national data, and International Shipping and Aviation,
11 which cannot be allocated to regions. Global rates of reduction in scenarios are shown for illustrative purposes
12 only and do not suggest rates of reduction at the regional or national level. {Figure 2.9, Figure 2.11}
13
14 START BOX TS.2 HERE
15 Box TS.2: GHG emission metrics provide simplified information about the effects of different
16 greenhouse gases
17 Comprehensive mitigation policy relies on consideration of all anthropogenic forcing agents, which
18 differ widely in their atmospheric lifetimes and impacts on the climate system. GHG emission metrics
19 provide simplified information about the effect that emissions of different gases have on global
20 temperature or other aspects of climate, usually expressed relative to the effect of emitting CO2ǂ. This
21 information can support choices about priorities, trade-offs and synergies in mitigation policies and
22 emission targets for non-CO2 gases relative to CO2 as well as baskets of gases expressed in CO2-eq.
23 The choice of metric can affect the timing and emphasis placed on reducing emissions of Short-Lived
24 Climate Forcers (SLCFs) relative to CO2 within multi-gas abatement strategies as well as the costs of
25 such strategies. Different metric choices can also alter the time at which net zero GHG emissions are
26 calculated to be reached for any given emissions scenario. A wide range of GHG emission metrics has
27 been published in the scientific literature, which differ in terms of: (i) the key measure of climate change
28 they consider, (ii) whether they consider climate outcomes for a specified point in time or integrated
29 over a specified time horizon, (iii) the time horizon over which the metric is applied, (iv) whether they
30 apply to a single emission pulse, to emissions sustained over a period of time, or to a combination of
31 both, and (v) whether they consider the climate effect from an emission compared to the absence of that
32 emission, or compared to a reference emissions level or climate state {Annex I}.
33 Parties to the Paris Agreement decided to report aggregated emissions and removals (expressed as CO2-
34 eq) based on the Global Warming Potential with a time horizon of 100 years (GWP100) using values
35 from IPCC AR5 or from a subsequent IPCC report as agreed upon by the CMA†, and to account for
36 future nationally determined contributions (NDCs) in accordance with this approach. Parties may also
37 report supplemental information on aggregate emissions and removals, expressed as CO2-eq, using
38 other GHG emission metrics assessed by the IPCC.
39 The WG III contribution to AR6 uses updated GWP100 values from AR6 WG I to report aggregate
40 emissions and removals unless stated otherwise. These reflect updated scientific understanding of the
41 response of the climate system to emissions of different gases and include a methodological update to
42 incorporate climate-carbon cycle feedbacks associated with the emission of non-CO2 gases (see Annex
43 II Part II Section 8 for a list of GWP100 metric values). The choice of GWP100 was made inter alia for
44 consistency with decisions under the Rulebook for the Paris Agreement and because it is the dominant
45 metric used in the literature assessed by WG III. Furthermore, for mitigation pathways that likely limit
46 global warming to 2°C or lower, using GWP100 to inform cost-effective abatement choices between
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1 gases would achieve such long-term temperature goals at close to least global cost within a few percent
2 (high confidence).
3 However, GWP100 is not well suited to estimate the cumulative effect on climate from sustained SLCF
4 emissions and the resulting warming at specific points in time. This is because the warming caused by
5 an individual SLCF emission pulse is not permanent, and hence, unlike CO2, the warming from
6 successive SLCF emission pulses over multiple decades or centuries depends mostly on their ongoing
7 rate of emissions rather than cumulative emissions. Recently developed step/pulse metrics such as the
8 CGTP (Combined Global Temperature Change Potential) and GWP* (referred to as GWP-star and
9 indicated by asterisk) recognise that a sustained increase/decrease in the rate of SLCF emissions has
10 indeed a similar effect on global surface temperature as one-off emission/removal of CO2. These metrics
11 use this relationship to calculate the CO2 emissions or removals that would result in roughly the same
12 temperature change as a sustained change in the rate of SLCF emissions (CGTP) over a given time
13 period, or as a varying time series of CH4 emissions (GWP*). From a mitigation perspective, this makes
14 these metrics well suited in principle to estimate the effect on the remaining carbon budget from more,
15 or less, ambitious SLCF mitigation over multiple decades compared to a given reference scenario (high
16 confidence). However, potential application in wider climate policy (e.g., to inform equitable and
17 ambitious emission targets or to support sector-specific mitigation policies) is contested and relevant
18 literature still limited.
19 All metrics have limitations and uncertainties, given that they simplify the complexity of the physical
20 climate system and its response to past and future GHG emissions. For this reason, the WG III
21 contribution to the AR6 reports emissions and mitigation options for individual gases where possible;
22 CO2-equivalent emissions are reported in addition to individual gas emissions where this is judged to
23 be policy-relevant. This approach aims to reduce the ambiguity regarding actual climate outcomes over
24 time arising from the use of any specific GHG emission metric. {Cross-Chapter Box 2 in Chapter 2,
25 Supplementary Material 2.3, Annex II Part II Section 8; WG I Chapter 7.6}
ǂ
26 Emission metrics also exist for aerosols, but these are not commonly used in climate policy. This assessment
27 focuses on GHG emission metrics only.
†
28 The CMA is the Conference of the Parties serving as the Meeting of the Parties to the Paris Agreement. See
29 18/CMA.1 (Annex, para 37) and 4/CMA.1 (Annex II, para 1) regarding the use of GHG emission metrics in
30 reporting of emissions and removals and accounting for Parties’ NDCs.
31 END BOX TS.2 HERE
32
33 Consumption-based CO2 emissions in developed countries and the Asia and Developing Pacific
34 region are higher than in other regions (high confidence). In developed countries, consumption-
35 based CO2 emissions peaked at 15 GtCO2 in 2007, declining to about 13 GtCO2 in 2018. The Asia and
36 Developing Pacific region, with 52% of current global population, has become a major contributor to
37 consumption-based CO2 emission growth since 2000 (5.5% yr-1 for 2000-2018); in 2015 it exceeded
38 the developed countries region, with 16% of global population, as the largest emitter of consumption-
39 based CO2. {2.3.2, Figure 2.14}
40 Carbon intensity improvements in the production of traded products has led to a net reduction
41 in CO2 emissions embodied in international trade (high confidence). A decrease in the carbon
42 intensity of traded products has offset increased trade volumes between 2006 and 2016. Emissions
43 embodied in internationally traded products depend on the composition of the global supply chain
44 across sectors and countries and the respective carbon intensity of production processes (emissions per
45 unit of economic output). {2.3, 2.4}
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1 Developed countries tend to be net CO2 emission importers, whereas developing countries tend
2 to be net emission exporters (high confidence). Net CO2 emission transfers from developing to
3 developed countries via global supply chains have decreased between 2006 and 2016. Between 2004
4 and 2011, CO2 emission embodied in trade between developing countries have more than doubled (from
5 0.47 to 1.1 Gt) with the centre of trade activities shifting from Europe to Asia. {2.3.4, Figure 2.15}
6 Territorial emissions from developing country regions continue to grow, mostly driven by
7 increased consumption and investment, albeit starting from a low base of per capita emissions
8 and with a lower historic contribution to cumulative emissions than developed countries (high
9 confidence). Average 2019 per capita CO2-FFI emissions in three developing regions Africa (1.2
10 tCO2), Asia and developing Pacific (4.4 tCO2), and Latin America and Caribbean (2.7 tCO2) remained
11 less than half of Developed Countries 2019 CO2-FFI emissions (9.5 tCO2). In these three developing
12 regions together, CO2-FFI emissions grew by 26% between 2010 and 2019 (compared to 260% between
13 1990 and 2010). In contrast, in Developed Countries emissions contracted by 9.9% between 2010-2019
14 and by 9.6% between 1990-2010. Historically, these three developing regions together contributed 28%
15 to cumulative CO2-FFI emissions between 1850 and 2019, whereas Developed Countries contributed
16 57%, and least developed countries contributed 0.4%. (Figure TS.5) {2.2, Figure 2.9, Figure 2.10}
17 Globally, households with income in the top 10% contribute about 36-45% of global GHG
18 emissions (robust evidence, medium agreement). About two thirds of the top 10% live in developed
19 countries and one third in other economies. The lifestyle consumption emissions of the middle income
20 and poorest citizens in emerging economies are between 5-50 times below their counterparts in high-
21 income countries (medium confidence). Increasing inequality within a country can exacerbate dilemmas
22 of redistribution and social cohesion and affect the willingness of the rich and poor to accept policies
23 to protect the environment, and to accept and afford lifestyle changes that favour mitigation (medium
24 confidence). {2.6.1, 2.6.2, Figure 2.29}
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1
2
3 Figure TS.5: Global emissions are distributed unevenly, both in the present day and cumulatively since 1850
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1 Figure TS.5 legend: Panel a shows the distribution of regional GHG emissions in tonnes CO2-eq per
2 capita by region in 2019. GHG emissions are categorised into: CO2 Fossil fuel and industry (CO2-FFI), CO2
3 Land use, land use change, forestry (CO2-LULUCF) and other GHG emissions (CH4, nitrous oxide, F-gas,
4 expressed in CO2-eq using GWP100). The height of each rectangle shows per-capita emissions, the width shows
5 the population of the region, so that the area of the rectangles refers to the total emissions for each
6 regional. Percentages refer to overall GHG contributions to total global emissions in 2019. Emissions from
7 international aviation and shipping are not included.
8 Panel b shows the share of historical net CO2 emissions per region from 1850 to 2019. This includes CO2-FFI
9 and CO2-LULUCF (GtCO2). Other GHG emissions are not included. Emissions from international aviation and
10 shipping are included. {1.3, Figure 1.2a, 2.2, Figure 2.10}
11
12 Globally, GHG emissions continued to rise across all sectors and subsectors, and most rapidly in
13 transport and industry (high confidence). In 2019, 34% (20 GtCO2-eq) of global GHG emissions
14 came from the energy sector, 24% (14 GtCO2-eq) from industry, 22% (13 GtCO2-eq) from agriculture,
15 forestry and other land use (AFOLU), 15% (8.7 GtCO2-eq) from transport, and 5.6% (3.3 GtCO2-eq)
16 from buildings. Once indirect emissions from energy use are considered, the relative shares of industry
17 and buildings emissions rise to 34% and 17%, respectively. Average annual GHG emissions growth
18 during 2010-2019 slowed compared to the previous decade in energy supply (from 2.3% to 1.0%) and
19 industry (from 3.4% to 1.4%, direct emissions only), but remained roughly constant at about 2% per
20 year in the transport sector (high confidence). Emission growth in AFOLU is more uncertain due to the
21 high share of CO2-LULUCF emissions. (Figure TS.8) {2.2.4, Figures 2.13, Figures 2.16-2.21}
22 There is a discrepancy, equating to 5.5 GtCO2 yr-1, between alternative methods of accounting for
23 anthropogenic land CO2 fluxes. Accounting for this discrepancy would assist in assessing
24 collective progress in a global stocktake (high confidence). The principal accounting approaches are
25 National GHG inventories (NGHGI) and global modelling9 approaches. NGHGI, based on IPCC
26 guidelines, consider a much larger area of forest to be under human management than global models.
27 NGHGI consider the fluxes due to human-induced environmental change on this area to be
28 anthropogenic and are thus reported. Global models, in contrast, consider these fluxes to be natural and
29 are excluded from the total reported anthropogenic land CO2 flux. The accounting method used will
30 affect the assessment of collective progress in a global stocktake {Cross-Chapter Box 6 in Chapter 7}
31 (medium confidence). In the absence of these adjustments, allowing a like with like comparison,
32 collective progress would appear better than it is. {7.2}
33 This accounting discrepancy also applies to Integrated Assessment Models (IAMs), with the
34 consequence that anthropogenic land CO2 fluxes reported in IAM pathways cannot be compared
35 directly with those reported in national GHG inventories (high confidence). Methodologies
36 enabling a more like-for-like comparison between models’ and countries’ approaches would
37 support more accurate assessment of the collective progress achieved under the Paris Agreement. {3.4,
38 7.2.2}
39 Average annual growth in GHG emissions from energy supply decreased from 2.3% for 2000–
40 2009 to 1.0% for 2010–2019 (high confidence). This slowing of growth is attributable to further
41 improvements in energy efficiency and reductions in the carbon intensity of energy supply driven by
42 fuel switching from coal to gas, reduced expansion of coal capacity, particularly in Eastern Asia, and
43 the increased use of renewables (medium confidence). (Figure TS.6) {2.2.4, 2.4.2.1, Figure 2.17}
44 The industry, buildings and transport sectors make up 44% of global GHG emissions, or 66%
45 when the emissions from electricity and heat production are reallocated as indirect emissions (high
46 confidence). This reallocation makes a substantial difference to overall industry and buildings
FOOTNOTE 9 Bookkeeping models and dynamic global vegetation models
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1 emissions as shown in Figure TS.6. Industry, buildings, and transport emissions are driven, respectively,
2 by the large rise in demand for basic materials and manufactured products, a global trend of increasing
3 floor space per capita, building energy service use, travel distances, and vehicle size and weight.
4 Between 2010-2019, aviation grew particularly fast on average at 3.3% per annum. Globally, energy
5 efficiency has have improved in all three demand sectors, but carbon intensities have not. (Figure TS.6)
6 {2.2.4, Figure 2.18, Figure 2.19, Figure 2.20}
7
8
Total emissions (59 GtCO2eq)
9
Direct + indirect emissions by end-use sector (59 GtCO2eq)
(59 GtCO2eq)
10
11 Figure TS.6: Total anthropogenic direct and indirect GHG emissions for the year 2019 (in GtCO2eq) by
12 sector and sub-sector
13 Figure TS.6 legend: Direct emissions estimates assign emissions to the sector in which they arise (scope 1
14 reporting). Indirect emissions – as used here - refer to the reallocation of emissions from electricity and heat to
15 the sector of final use (scope 2 reporting). Note that cement refers to process emissions only, as a lack of data
16 prevents the full reallocation of indirect emissions to this sector. More comprehensive conceptualisations of
17 indirect emissions including all products and services (scope 3 reporting) are discussed in Chapter 2 section 2.3.
18 Emissions are converted into CO2-equivalents based on global warming potentials with a 100-year time horizon
19 (GWP100) from the IPCC Sixth Assessment Report. Percentages may not add up to 100 across categories due to
20 rounding at the second significant digit. {Figure 2.12, 2.3}
21 Providing access to modern energy services universally would increase global GHG emissions by
22 a few percent at most (high confidence). The additional energy demand needed to support decent
23 living standards10 for all is estimated to be well below current average energy consumption (medium
24 evidence, high agreement). More equitable income distribution could also reduce carbon emissions, but
FOOTNOTE 10 Decent Living Standards (DLS) – a benchmark of material conditions for human well-being –
overlaps with many Sustainable Development Goals (SDGs). Minimum requirements of energy use consistent
with enabling well-being for all is between 20 and 50 GJ cap-1 yr-1 23 depending on the context. (Figure TS.22)
{5.2.2, 5.2.2, Box 5.3}
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1 the nature of this relationship can vary by level of income and development (limited evidence, medium
2 agreement). {2.4.3}
3 Evidence of rapid energy transitions exists in some case studies (medium confidence). Emerging
4 evidence since AR5 on past energy transitions identifies a growing number of cases of accelerated
5 technology diffusion at sub-global scales and describes mechanisms by which future energy transitions
6 may occur more quickly than those in the past. Important drivers include technology transfer and
7 cooperation, international policy and financial support, and harnessing synergies among technologies
8 within a sustainable energy system perspective (medium confidence). A fast global low-carbon energy
9 transition enabled by finance to facilitate low-carbon technology adoption in developing and
10 particularly in least developed countries can facilitate achieving climate stabilisation targets (high
11 confidence). {2.5.2, Table 2.5}
12 Multiple low-carbon technologies have shown rapid progress since AR5 – in cost, performance,
13 and adoption – enhancing the feasibility of rapid energy transitions (high confidence). The rapid
14 deployment and unit cost decrease of modular technologies like solar, wind, and batteries have occurred
15 much faster than anticipated by experts and modelled in previous mitigation scenarios, as shown in
16 Figure TS.7 (high confidence). The political, economic, social, and technical feasibility of solar energy,
17 wind energy and electricity storage technologies has improved dramatically over the past few years. In
18 contrast, the adoption of nuclear energy and CO2 capture and storage (CCS) in the electricity sector has
19 been slower than the growth rates anticipated in stabilisation scenarios. Emerging evidence since AR5
20 indicates that small-scale technologies (e.g., solar, batteries) tend to improve faster and be adopted more
21 quickly than large-scale technologies (nuclear, CCS) (medium confidence). (Figure TS.7, Box TS.15)
22 {2.5.3, 2.5.4, Figure 2.22, Figure 2.23}
23
24
25 Figure TS.7: The unit costs of batteries and some forms of renewable energy have fallen significantly,
26 and their adoption continues to increase
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1 Figure TS.7 legend: The upper panel shows levelised costs of electricity (LCOE) for rapidly changing
2 mitigation technologies. Solid blue lines indicate average market cost in each year. Light blue shaded areas
3 show the range between the 5th and 95th percentiles in each year. Grey shading indicates the range of fossil fuel
4 (coal and gas) LCOE in 2020 (corresponding to USD55-148 per MWh). LCOE allows consistent comparisons
5 of cost trends across a diverse set of energy technologies to be made; it does not include environmental
6 externalities and does not reflect variation in the value of electricity over time and space (see Chapter 6).
7 The lower panel shows cumulative global adoption for each technology, in GW of installed capacity for
8 renewable energy and in millions of vehicles for electric vehicles. A vertical dashed line is placed in 2010 to
9 indicate change since AR5. The market share percentages shown are the 2020 shares based on provisional data,
10 i.e., percentage of total electricity production (for PV, Onshore wind, Offshore wind, concentrating solar power
11 (CSP)) and of passenger total vehicles (for electric vehicles). The electricity market share is generally lower
12 than the share of production capacity given lower capacity factors for these renewable technologies. {2.5, 6.4}
13
14 Robust incentives for investment in innovation, especially incentives reinforced by national policy
15 and international agreements, are central to accelerating low-carbon technological change (robust
16 evidence, medium agreement). Policies have driven innovation, including instruments for technology
17 push (e.g., scientific training, research and development (R&D)) and demand pull (e.g., carbon pricing,
18 adoption subsidies), as well as those promoting knowledge flows and especially technology transfer.
19 The magnitude of the scale-up challenge elevates the importance of rapid technology development and
20 adoption. This includes ensuring participation of developing countries in an enhanced global flow of
21 knowledge, skills, experience, equipment, and technology itself requires strong financial, institutional,
22 and capacity building support. {2.5.4, 2.5, 2.8}
23 Estimates of future CO2 emissions from existing fossil fuel infrastructures already exceed
24 remaining cumulative net CO2 emissions in pathways limiting warming to 1.5°C with no or
25 limited overshoot (high confidence). Assuming variations in historic patterns of use and
26 decommissioning, estimated future CO2 emissions from existing fossil fuel infrastructure alone are 660
27 (460-890) GtCO2 and from existing and currently planned infrastructure 850 (600-1100) GtCO2. This
28 compares to overall cumulative net CO2 emissions until reaching net zero CO2 of 510 (330-710) GtCO2
29 in pathways that limit warming to 1.5°C with no or limited overshoot, and 890 (640-1160) GtCO2 in
30 pathways that likely limit warming to 2°C (high confidence). While most future CO2 emissions from
31 existing and currently planned fossil fuel infrastructure are situated in the power sector, most remaining
32 fossil fuel CO2 emissions in pathways that likely limit warming to 2°C and below are from non-electric
33 energy – most importantly from the industry and transportation sectors (high confidence).
34 Decommissioning and reduced utilisation of existing fossil fuel installations in the power sector as well
35 as cancellation of new installations are required to align future CO2 emissions from the power sector
36 with projections in these pathways (high confidence). (Figure TS.8) {2.7.2, 2.7.3, Figure 2.26, Table
37 2.6, Table 2.7}
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1
2
3 Figure TS.8: Future CO2 emissions from existing and currently planned fossil fuel infrastructure in the
4 context of Paris carbon budgets in GtCO2 based on historic patterns of infrastructure lifetimes and
5 capacity utilisation
6 Figure TS.8 legend: Future CO2 emissions estimates of existing infrastructure for the electricity sector as well
7 as all other sectors (industry, transport, buildings, other fossil fuel infrastructures) and of proposed
8 infrastructures for coal power as well as gas and oil power. Grey bars on the right depict the range (5th – 95th
9 percentile) in overall cumulative net CO2 emissions until reaching net zero CO2 in pathways that limit warming
10 to 1.5°C with no or limited overshoot (1.5°C scenarios), and in pathways that limit likely warming to 2°C (2°C
11 scenarios). {Figure 2.26}
12
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1 TS. 4 Mitigation and development pathways
2 While previous WG III assessments have explored mitigation pathways, since AR5 there has been an
3 increasing emphasis in the literature on development pathways, and in particular at the national scale.
4 Chapter 4 assesses near-term (2019-2030) to mid-term (2030- 2050) pathways, complementing Chapter
5 3 which focusses on long-term pathways (up to 2100). While there is considerable literature on country-
6 level mitigation pathways, including but not limited to NDCs, the country distribution of this literature
7 is very unequal (high confidence). {4.2.1, Cross-Chapter Box 4 in Chapter 4}
8 TS. 4.1 Mitigation and development pathways in the near- to mid-term
9 An emissions gap persists, exacerbated by an implementation gap, despite mitigation efforts
10 including those in nationally determined contributions (NDCs). In this report the emissions gap is
11 understood as the difference between projected global emissions with national determined contributions
12 (NDCs) in 2030, and emissions in 2030 if mitigation pathways consistent with the Paris temperature
13 goals were achieved. The term implementation gap refers to the gap between NDC mitigation pledges,
14 and the expected outcome of existing policies.
15 Pathways consistent with the implementation and extrapolation of countries’ current11 policies
16 see GHG emissions reaching 57 (52-60) GtCO2-eq yr-1 by 2030 and to 46-67 GtCO2-eq yr-1 by
17 2050, leading to a median global warming of 2.4°C to 3.5°C by 2100 (medium confidence). NDCs
18 with unconditional and conditional elements12 lead to 53 (50-57) and 50 (47-55) GtCO2-eq, respectively
19 (medium confidence). {Table 4.1}. This leaves median estimated emissions gaps of 14-23 GtCO2-eq to
20 limit warming to 2°C and 25-34 GtCO2-eq to limit warming to 1.5°C relative to mitigation pathways.
21 (Figure TS.9) {Cross-Chapter Box 4 Figure 1 in Chapter 4}
FOOTNOTE 11 Current NDCs refers to the most recent nationally determined contributions submitted to the
UNFCCC as well as those publicly announced (with sufficient detail on targets, but not yet submitted) up to 11
October 2021, and reflected in literature published up to 11 October 2021. Original INDCs and NDCs refer to
those submitted to the UNFCCC in 2015 and 2016.
FOOTNOTE 12 See {4.2.1} for description of ‘unconditional’ and ‘conditional’ elements of NDCs.
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1
2 Figure TS.9 Aggregate GHG emissions of global mitigation pathways (coloured funnels and bars) and
3 projected emission outcomes from current policies and emissions implied by unconditional and
4 conditional elements of NDCs, based on updates available by 11 October 2021 (grey bars).
5 Figure TS.9 legend: Shaded areas show GHG emission medians and 25th–75th percentiles over 2020–2050 for
6 four types of pathways in the AR6 scenario database: i) Pathways with near-term emissions developments in
7 line with current policies and extended with comparable ambition levels beyond 2030; ii) Pathways likely to
8 limit warming to 2°C with near term emissions developments reflecting 2030 emissions implied by current
9 NDCs followed by accelerated emissions reductions; iii) Pathways likely to limit warming to 2°C based on
10 immediate actions from 2020 onwards; iv) Pathways that limit warming to 1.5°C with no or limited overshoot.
11 Right hand panels show two snapshots of the 2030 and 2050 emission ranges of the pathways in detail (median,
12 25th–75th and 5th–95th percentiles). The 2030 snapshot includes the projected emissions from the implementation
13 of the NDCs as assessed in Chapter 4.2 (Table 4.1; median and full range). Historic GHG emissions trends as
14 used in model studies are shown for 2010–2015. GHG emissions are in CO2-equivalent using GWP100 values
15 from AR6. {3.5, Table 4.1, Cross-Chapter Box 4 in Chapter 4}
16 Projected global emissions from aggregated NDCs place limiting global warming to 1.5°C beyond
17 reach and make it harder after 2030 to limit warming to 2°C (high confidence). Pathways
18 following NDCs until 2030 show a smaller reduction in fossil fuel use, slower deployment of low carbon
19 alternatives, and a smaller reduction in CO2, CH4 and overall GHG emissions in 2030 compared to
20 immediate action scenarios. This is followed by a much faster reduction of emissions and fossil fuels
21 after 2030, and a larger increase in the deployment of low carbon alternatives during the medium term
22 in order to get close to the levels of the immediate action pathways in 2050. Those pathways also deploy
23 a larger amount of Carbon Dioxide Removal (CDR) to compensate for higher emissions before 2030.
24 The faster transition during 2030-2050 entails greater investment in fossil fuel infrastructure and lower
25 deployment of low carbon alternatives in 2030 which adds to the socio-economic challenges in realising
26 the higher transition rates. (TS 4.2) {3.5}
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1 Studies evaluating up to 105 updated NDCs13 indicate that emissions in NDCs with conditional
2 elements have been reduced by 4.5 (2.7-6.3) GtCO2-eq. This closes the emission gaps by about one-
3 third to 2°C and about 20% to 1.5°C compared to the original NDCs submitted in 2015/16 (medium
4 confidence). 4.2.2, Cross-Chapter Box 4 in Chapter 4}. An implementation gap also exists between the
5 projected emissions with ‘current policies’ and the projected emissions resulting from the
6 implementation of the unconditional and conditional elements of NDCs; this is estimated to be around
7 4 and 7 GtCO2-eq in 2030, respectively {4.2.2} (medium confidence). Many countries would therefore
8 require additional policies and associated action on climate change to meet their autonomously
9 determined mitigation targets as specified under the first NDCs (limited evidence). The disruptions
10 triggered by the COVID-19 pandemic increase uncertainty over the range of projections relative to pre-
11 COVID-19 literature. As indicated by a growing number of studies at the national and global level, how
12 large near- to mid-term emissions implications of the COVID-19 pandemic are, to a large degree
13 depends on how stimulus or recovery packages are designed. {4.2}
14
15
FOOTNOTE 13 Submitted by 11 October 2021.
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1 Table TS.2: Comparison of key characteristics of mitigation pathways with immediate action towards limiting warming to 1.5-2°C vs. pathways following current
2 NDCs until 2030.
Mitigation pathways
median (interquartile range)
<1.5°C 1.5°C by 2100 Likely < 2°C
Global indicators Immediate action, no or limited overshoot NDCs until 2030, with high overshoot of 1.5°C
Immediate action NDCs until 2030
Scenarios category: C1 subset of scenarios category: C2 Scenarios category:C3a Scenarios category: C3b
Cumulative net negative CO2 until 2100 (GtCO2) 190 (0,385) 320 (250,440) 10 (0,120) 70 (0,200)
Kyoto GHG emissions in 2030 (% rel to 2019) -45 (-50,-40) -5 (-5,0) -25 (-35,-20) -5 (-10,0)
in 2050 (% rel to 2019) -85 (-90,-80) -75 (-85,-70) -65 (-70,-60) -70 (-70,-60)
CO2 emissions change in 2030 (% rel to 2019) -50 (-60,-40) -5 (-5,0) -25 (-35,-20) -5 (-5,0)
in 2050 (% rel to 2019) -100 (-105,-95) -85 (-95,-80) -70 (-80,-65) -75 (-80,-65)
CH4 emissions in 2030 (% rel to 2019) -35 (-40,-30) -5 (-5,0) -25 (-35,-20) -10 (-15,-5)
in 2050 (% rel to 2019) -50 (-60,-45) -50 (-60,-45) -45 (-50,-40) -50 (-65,-45)
Primary energy from coal in 2030 (% rel to 2019) -75 (-80,-65) -10 (-20,-5) -50 (-65,-35) -15 (-20,-10)
in 2050 (% rel to 2019) -95 (-100,-80) -90 (-100,-85) -85 (-100,-65) -80 (-90,-70)
Primary energy from oil in 2030 (% rel to 2019) -10 (-25,0) 5 (5,10) 0 (-10,10) 10 (5,10)
in 2050 (% rel to 2019) -60 (-75,-40) -50 (-65,-30) -30 (-45,-15) -40 (-55,-20)
Primary energy from gas in 2030 (% rel to 2019) -10 (-30,0) 15 (10,25) 10 (0,15) 15 (10,15)
in 2050 (% rel to 2019) -45 (-60,-20) -45 (-55,-25) -10 (-35,15) -30 (-45,-5)
Primary energy from nuclear in 2030 (% rel to 2019) 40 (5,70) 10 (0,25) 35 (5,50) 10 (0,30)
in 2050 (% rel to 2019) 90 (10,305) 100 (40,135) 85 (30,200) 75 (30,120)
Primary energy from biomass in 2030 (% rel to 2019) 75 (55,130) 45 (20,75) 60 (35,105) 45 (10,80)
in 2050 (% rel to 2019) 290 (215,430) 230 (170,440) 240 (130,355) 260 (95,435)
Primary energy from non-biomass renewables in 2030 (% rel to 2019) 225 (150,270) 100 (85,145) 150 (115,190) 115 (85,130)
in 2050 (% rel to 2019) 725 (540,955) 665 (515,925) 565 (415,765) 625 (545,705)
Carbon intensity of electricity in 2030 (% rel to 2019) -75 (-85,-70) -30 (-40,-30) -60 (-70,-50) -35 (-40,-30)
in 2050 (% rel to 2019) -100 (-100,-100) -100 (-100,-100) -95 (-100,-95) -100 (-100,-95)
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1 Table TS.2 legend: Key characteristics are reported for four groups of mitigation pathways: (i) immediate
2 action to limit warming to 1.5°C with no or limited overshoot (C1 in Table TS.3; 97 scenarios), (ii) near team
3 action following the NDCs until 2030 and returning warming to below 1.5°C (50% chance) by 2100 with high
4 overshoot (subset of 42 scenarios following the NDCs until 2030 in C2), (iii) immediate action to likely limit
5 warming to 2°C, (C3a in Table TS.3; 204 scenarios) and (iv) near term action following the NDCs until 2030
6 followed by post-2030 action to likely limit warming to 2°C (C3b in Table TS.3; 97 scenarios). The groups (i),
7 (iii), and (iv) are depicted in Figure TS.9. Reported are median and interquartile ranges (in brackets) for selected
8 global indicators. Numbers are rounded to the nearest five. Changes from 2019 are relative to modelled 2019
9 values. Emissions reductions are based on harmonised model emissions used for the climate assessment.
10 (Section 3.5) {Table 3.6}
11
12 There is a need to explore how accelerated mitigation – relative to NDCs and current policies –
13 could close both emission gaps, and implementation gaps. There is increasing understanding of the
14 technical content of accelerated mitigation pathways, differentiated by national circumstances, with
15 considerable, though uneven, literature at country-level (medium evidence, high agreement).
16 Transformative technological and institutional changes for the near-term include demand reductions
17 through efficiency and reduced activity, rapid decarbonisation of the electricity sector and low-carbon
18 electrification of buildings, industry and transport (robust evidence, medium agreement). A focus on
19 energy use and supply is essential, but not sufficient on its own – the land sector and food systems
20 deserve attention. The literature does not adequately include demand-side options and systems analysis,
21 and captures the impact from non-CO2 GHGs with medium confidence. {4.2.5}
22 If obstacles to accelerated mitigation are rooted in underlying structural features of society, then
23 transforming such structures can support emission reductions {4.2.6}. Countries and regions will
24 have different starting points for transition pathways. Some critical differences between countries
25 include climate conditions resulting in different heating and cooling needs, endowments with different
26 energy resources, patterns of spatial development, and political and economic conditions {4.2.5}. The
27 way countries develop determines their capacity to accelerate mitigation and achieve other sustainable
28 development objectives simultaneously (medium confidence) {4.3.1, 4.3.2}. Yet meeting ambitious
29 mitigation and development goals cannot be achieved through incremental change (robust evidence,
30 medium agreement). Though development pathways result from the actions of a wide range of actors,
31 it is possible to shift development pathways through policies and enhancing enabling conditions (limited
32 evidence, medium agreement).
33 Shifting development pathways towards sustainability offers ways to broaden the range of levers
34 and enablers that a society can use to accelerate mitigation and increases the likelihood of making
35 progress simultaneously on climate action and other development goals (Box TS.3) {Cross-
36 Chapter Box 5 in Chapter 4, Figure 4.7, 4.3}. There are practical options to shift development
37 pathways in ways that advance mitigation and other sustainable development objectives, supporting
38 political feasibility, increase resources to meet multiple goals, and reduce emissions (limited evidence,
39 high agreement). Concrete examples, assessed in chapter 4 of this report, include high employment and
40 low emissions structural change, fiscal reforms for mitigation and social contract, combining housing
41 policies to deliver both housing and transport mitigation, and change economic, social and spatial
42 patterns of development of the agriculture sector provide the basis for sustained reductions in emissions
43 from deforestation. {4.4.1, 4.4, 1.10}
44
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1 START BOX TS.3 HERE
2 Box TS.3: Shifting development pathways to increase sustainability and broaden mitigation
3 options
4 In this report, development pathways refer to the patterns of development resulting from multiple
5 decisions and choices made by many actors in the national and global contexts. Each society whether
6 in developing or developed regions follows its own pattern of growth (Figure TS.13). Development
7 pathways can also be described at smaller scales (e.g., for regions or cities) and for sectoral systems.
8 Development pathways are major drivers of GHG emissions {1, 2}. There is compelling evidence to
9 show that continuing along existing development pathways will not achieve rapid and deep emission
10 reductions. In the absence of shifts in development pathways, conventional mitigation policy
11 instruments may not be able to limit global emissions to a degree sufficient to meet ambitious mitigation
12 goals or they may only be able to do so at very high economic and social costs.
13 Policies to shift development pathways, on the other hand, make mitigation policies more effective.
14 Shifting development pathways broadens the scope for synergies between sustainable development
15 objectives and mitigation. Development pathways also determine the enablers and levers available for
16 adaptation {AR6 WG II TS E.1.2} and for achieving other SDGs.
17 There are many instances in which reducing GHG emissions and moving towards the achievement of
18 other development objectives can go hand in hand {Chapter 3, Fig 3.33, Chapters 6-12, 17}. Integrated
19 policies can support the creation of synergies between action to combat climate change and its impacts
20 (SDG 13) and other SDGs. For example, when measures promoting walkable urban areas are combined
21 with electrification and clean renewable energy, there are several co-benefits to be attained. These
22 include reduced pressures on agricultural land from reduced urban growth, health co-benefits from
23 cleaner air and benefits from enhanced mobility {8.2, 8.4, 4.4.1}. Energy efficiency in buildings and
24 energy poverty alleviation through improved access to clean fuels also deliver significant health
25 benefits. {9.8.1 and 9.8.2}
26 However, decisions about mitigation actions, and their timing and scale, may entail trade-offs with the
27 achievement of other national development objectives in the near-, mid- and long-term {Chapter 12}.
28 In the near-term, for example, regulations may ban vehicles from city centres to reduce congestion and
29 local air pollution but reduce mobility and choice. Increasing green spaces within cities without caps
30 on housing prices may involve trade-offs with affordable housing and push low-income residents
31 outside the city {8.2.2}. In the mid- and long-term, large-scale deployment of biomass energy raises
32 concerns about food security and biodiversity conservation {3.7.1, 3.7.5, 7.4.4, 9.8.1, 12.5.2, 12.5.3}.
33 Prioritising is one way to manage these trade-offs, addressing some national development objectives
34 earlier than others. Another way is to adopt policy packages aimed at shifting development pathways
35 towards sustainability (SDPS) as they expand the range of tools available to simultaneously achieve
36 multiple development objectives and accelerate mitigation. (Box TS.3 Figure 1)
37 What does shifting development pathways towards sustainability entail?
38 Shifting development pathways towards sustainability implies making transformative changes that
39 disrupt existing developmental trends. Such choices would not be marginal, but include technological,
40 systemic and socio-behavioural changes {4.4}. Decision points also arise with new infrastructure,
41 sustainable supply chains, institutional capacities for evidence-based and integrated decision-making,
42 financial alignment towards low-carbon socially responsible investments, just transitions and shifts in
43 behaviour and norms to support shifts away from fossil fuel consumption. Adopting multi-level
44 governance modes, tackling corruption where it inhibits shifts to sustainability, and improving social
45 and political trust are also key for aligning and supporting long-term environmentally just policies and
46 processes. {4.4, Cross-Chapter Box 5 in Chapter 4}
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1 How to shift development pathways?
2 Shifting development paths is complex. Changes that involve ‘dissimilar, unfamiliar and more complex
3 science-based components’ take more time, acceptance and legitimation and involve complex social
4 learning, even when they promise large gains. Despite the complexities of the interactions that result in
5 patterns of development, history also shows that societies can influence the direction of development
6 pathways based on choices made by decision-makers, citizens, the private sector, and social
7 stakeholders. Shifts in development pathways result from both sustained political interventions and
8 bottom-up changes in public opinion. Collective action by individuals as part of social movements or
9 lifestyle changes underpins system change. {5.2.3, 5.4.1, 5.4.5}.
10 Sectoral transitions that aim to shift development pathways often have multiple objectives and deploy
11 a diverse mix of policies and institutional measures. Context specific governance conditions can
12 significantly enable or disable sectoral transitions {Cross-Chapter Box 12 in Chapter 16}.
13 The necessary transformational changes are anticipated to be more acceptable if rooted in the
14 development aspirations of the economy and society within which they take place and may enable a
15 new social contract to address a complex set of inter-linkages across sectors, classes, and the whole
16 economy. Taking advantage of windows of opportunity and disruptions to mindsets and socio-technical
17 systems could advance deeper transformations.
18 How can shifts in development pathways be implemented by actors in different contexts?
19 Shifting development pathways to increased sustainability is a shared aspiration. Yet since countries
20 differ in starting points (e.g., social, economic, cultural, political) and historical backgrounds, they have
21 different urgent needs in terms of facilitating the economic, social, and environmental dimensions of
22 sustainable development and, therefore, give different priorities {4.3.2, 17.1}. The appropriate set of
23 policies to shift development pathways thus depends on national circumstances and capacities.
24 Shifting development pathways towards sustainability needs to be supported by multilateral
25 partnerships to strengthen suitable capacity, technological innovation (TS 6.5), and financial flows (TS.
26 6.4). The international community can play a particularly key role by helping ensure the necessary broad
27 participation in climate-mitigation efforts, including by countries at different development levels,
28 through sustained support for policies and partnerships that support shifting development pathways
29 towards sustainability while promoting equity and being mindful of different transition capacities.
30 {Chapter 4.3, 16.5, 16.6}
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1
2 Box TS.3 Figure 1 Shifting development pathways to increased sustainability: Choices by a wide range of
3 actors at key decision points on development pathways can reduce barriers and provide more tools to
4 accelerate mitigation and achieve other Sustainable Development Goals. {4.7}
5 END BOX TS.3 HERE
6
7 Policies can shift development pathways. There are examples of policies implemented in the
8 pursuit of overall societal development objectives, such as job creation, macro-economic stability,
9 economic growth, and public health and welfare. In some countries, such policies are framed as part
10 of a just transition (Box TS.3), however, they can have major influence on mitigative capacity, and
11 hence can be seen as tools to broaden mitigation options (medium confidence) {4.3.3}. Coordinated
12 policy mixes would need to orchestrate multiple actors – individuals, groups and collectives, corporate
13 actors, institutions and infrastructure actors – to deepen decarbonisation and shift pathways towards
14 sustainability. Shifts in one country may spill over to other countries. Shifting development pathways
15 can jointly support mitigation and adaptation {4.4.2}. Some studies explore the risks of high complexity
16 and potential delay attached to shifting development pathways. (Box TS.4, Figure TS.11) {4.4.3}
17 An increasing number of mitigation strategies up to 2050 (mid-term) have been developed by
18 various actors. A growing number of such strategies aim at net zero GHG or CO2 emissions, but
19 it is not yet possible to draw global implications due to the limited size of sample (medium
20 evidence; low agreement) {4.2.4}. Non-state actors are also engaging in a wide range of mitigation
21 initiatives. When adding up emission reduction potentials, sub-national and non-state international
22 cooperative initiatives could reduce emissions by up to about 20 GtCO2-eq in 2030 (limited evidence,
23 medium agreement) {4.2.3}. Yet perceived or real conflicts between mitigation and other SDGs can
24 impede such action. If undertaken without precaution, accelerated mitigation is found to have
25 significant implications for development objectives and macroeconomic costs at country level. The
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1 literature shows that employment effect of mitigation policies tends to be limited on aggregate but can
2 be significant at sectoral level (limited evidence, medium agreement). Detailed design of mitigation
3 policies is critical for distributional impacts and avoiding lock-in (high confidence), though further
4 research is needed in that direction. {4.2.6}
5 The literature identifies a broad set of enabling conditions that can both foster shifting
6 development pathways and accelerated mitigation (medium evidence, high agreement). Policy
7 integration is a necessary component of shifting development pathways, addressing multiple objectives.
8 To this aim, mobilising a range of policies is preferable to single policy instruments (high confidence).
9 {4.4.1}. Governance for climate mitigation and shifting development pathways is enhanced when
10 tailored to national and local contexts. Improved institutions and effective governance enable ambitious
11 action on climate and can help bridge implementation gaps (medium evidence, high agreement). Given
12 that strengthening institutions may be a long-term endeavour, it needs attention in the near-term {4.4.1}.
13 Accelerated mitigation and shifting development pathways necessitates both re-directing existing
14 financial flows from high- to low-emissions technologies and systems and to provide additional
15 resources to overcome current financial barriers (high confidence) {4.4.1}. Opportunities exist in the
16 near-term to close the finance gap {15.2.2}. At the national level, public finance for actions promoting
17 sustainable development helps broaden the scope of mitigation (medium confidence). Changes in
18 behaviour and lifestyles are important to move beyond mitigation as incremental change, and when
19 supporting shifts to more sustainable development pathways will broaden the scope of mitigation
20 (medium confidence). {4.4.1, Figure 4.8}
21 Some enabling conditions can be put in place relatively quickly while some others may take time
22 to establish underscoring the importance of early action (high confidence). Depending on context,
23 some enabling conditions such as such as promoting innovation may take time to establish. Other
24 enabling conditions, such as improved access to financing, can be put in place in a relatively short time
25 frame, and can yield rapid results {4.4, Figure 5.14, 13.9, 14.5, 15.6, 16.3, 16.4, 16.5, Cross-Chapter
26 Box 12 in Chapter 16}. Focusing on development pathways and considering how to shift them may also
27 yield rapid results by providing tools to accelerate mitigation and achieve other sustainable development
28 goals. {4.4.1}. Charting just transitions to net zero may provide a vision, which policy measures can
29 help achieve (Box TS.4, Box TS.8).
30 Equity can be an important enabler, increasing the level of ambition for accelerated mitigation
31 (high confidence) {4.5}. Equity deals with the distribution of costs and benefits and how these are
32 shared, as per social contracts, national policy and international agreements. Transition pathways have
33 distributional consequences such as large changes in employment and economic structure (high
34 confidence). The just transition concept has become an international focal point tying together social
35 movements, trade unions, and other key stakeholders to ensure equity is better accounted for in low-
36 carbon transitions (Box TS.4). The effectiveness of cooperative action and the perception of fairness of
37 such arrangements are closely related in that pathways that prioritise equity and allow broad stakeholder
38 participation can enable broader consensus for the transformational change implicit in the need for
39 deeper mitigation (robust evidence, medium agreement). (Box TS.4) {4.5, Figure 4.9}
40
41 START BOX TS.4 HERE
42 Box TS. 4: Just Transition
43 The Just Transition framework refers to a set of principles, processes and practices aimed at ensuring
44 that no people, workers, places, sectors, countries or regions are left behind in the move from a high-
45 carbon to a low-carbon economy. It includes respect and dignity for vulnerable groups; creation of
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1 decent jobs; social protection; employment rights; fairness in energy access and use and social dialogue
2 and democratic consultation with relevant stakeholders.
3 The concept has evolved, becoming prominent in the United States in 1980, related to environmental
4 regulations that resulted in job losses from highly polluting industries. Traced from a purely labour
5 movement, trade union space, the Just Transition framework emphasises that decent work and
6 environmental protection are not incompatible. During COP 24, with the Just Transition Silesia
7 Declaration, the concept gained in recognition and was signed by 56 Heads of State.
8 Implicit in a Just Transition is the notion of well-being, equity and justice – the realisation that
9 transitions are inherently disruptive and deliberate effort may be required to ensure communities
10 dependent on fossil-fuel based economies and industries do not suffer disproportionately {Chapter 4}.
11 ‘Just transitions’ are integral to the European Union as mentioned in the EU Green Deal, the Scottish
12 Government’s development plans and other national low carbon transition strategies. The US Green
13 New Deal Resolution puts structural inequality, poverty mitigation, and ‘Just Transitions’ at its centre.
14 There is a growing awareness of the need for shifting finance towards Just Transition in the context of
15 the COVID-19, in particular, public finance and governance have a major role in allowing Just
16 Transition broadly {Chapter 15}.
17 In the immediate aftermath of the COVID-19 pandemic, low oil prices created additional financial
18 problems for fossil fuel producer countries faced with loss of revenue and reduced fiscal latitude and
19 space. Public spending and social safety nets associated with the proceeds from producer economies
20 can be affected as assets become stranded and spending on strategic sustainable development goals such
21 as free education and health care services are neglected. Fiscal challenges are intricately linked to ‘Just
22 Transitions’ and the management associated with sustainable energy transition. There is no certainty on
23 how energy systems will recover post-COVID-19. However, ‘Just Transitions’ will have equity
24 implications if stimulus packages are implemented without due regard for the differentiated scales and
25 speeds and national and regional contexts, especially in the context of developing countries.
26 A Just Transition entails targeted and proactive measures from governments, agencies, and other non-
27 state authorities to ensure that any negative social, environmental, or economic impacts of economy-
28 wide transitions are minimised, whilst benefits are maximised for those disproportionally affected.
29 These proactive measures include eradication of poverty, regulating prosperity and creating jobs in
30 “green” sectors. In addition, governments, polluting industries, corporations, and those more able to
31 pay higher associated taxes, can pay for transition costs by providing a welfare safety net and adequate
32 compensation to people, communities, and regions that have been impacted by pollution, or are
33 marginalised, or are negatively impacted by a transition from a high- to low- carbon economy and
34 society. There is, nonetheless, increased recognition that resources that can enable the transition,
35 international development institutions, as well as other transitional drivers such as tools, strategies and
36 finance, are scarce. A sample of global efforts are summarised in Box TS.4 Figure 1.
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1
2 Box TS.4 Figure 1: Just Transitions around the world, 2020: Panel A shows commissions, task forces,
3 dialogues behind a Just Transition in many countries; Panel B shows the funds related to the Just
4 Transition within the European Union Green Deal, and Panel C shows the European Union’s Platform
5 for Coal Regions in Transition.{Figure 4.9}
6 END BOX TS.4 HERE
7
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1 TS. 4.2 Long-term mitigation pathways
2 The characteristics of a wide range of long-term mitigation pathways, their common elements
3 and differences are assessed in Chapter 3. Differences between pathways typically represent
4 choices that can steer the system in alternative directions through the selection of different
5 combinations of response options (high confidence). More than 2000 quantitative emissions
6 pathways were submitted to the AR6 scenarios database, of which more than 1200 pathways included
7 sufficient information for the associated warming to be assessed (consistent with AR6 WG I methods).
8 (Box TS.5) {3.2, 3.3}
9 Many pathways in the literature show how to likely limit global warming to 2°C with no overshoot
10 or to limit warming to 1.5°C with limited overshoot compared to 1850-1900. The likelihood of
11 limiting warming to 1.5°C with no or limited overshoot has dropped in AR6 WG III compared
12 to AR6 SR1.5 because global GHG emissions have risen since 2017, leading to higher near-term
13 emissions (2030) and higher cumulative CO2 emissions until the time of net zero (medium
14 confidence). Only a small number of published pathways limit global warming to 1.5°C without
15 overshoot over the course of the 21st century. {3.3, Annex III.II.3}
16 Mitigation pathways limiting warming to 1.5°C with no or limited overshoot reach 50% CO 2
17 reductions in the 2030s, relative to 2019, then reduce emissions further to reach net zero CO 2
18 emissions in the 2050s. Pathways likely limiting warming to 2°C reach 50% reductions in the
19 2040s and net zero CO2 by 2070s (medium confidence). (Figure TS.10, Box TS.6) {3.3}
20 Cost-effective mitigation pathways assuming immediate action to likely limit warming to 2°C are
21 associated with net global GHG emissions of 30-49 GtCO2-eq yr-1 by 2030 and 13-26 GtCO2-eq
22 yr-1 by 2050 (medium confidence). This corresponds to reductions, relative to 2019 levels, of 13-45%
23 by 2030 and 52-76% by 2050. Pathways that limit global warming to below 1.5°C with no or limited
24 overshoot require a further acceleration in the pace of transformation, with net GHG emissions typically
25 around 21-36 GtCO2-eq yr-1 by 2030 and 1-15 GtCO2-eq yr-1 by 2050; this corresponds to reductions of
26 34–60% by 2030 and 73-98% by 2050 relative to 2019 levels. {3.3}
27
28 START BOX TS.5 HERE
29 Box TS.5: Illustrative Mitigation Pathways (IMPs), and Shared Socio-economic Pathways
30 (SSPs)
31 The Illustrative Mitigation Pathways (IMPs)
32 The over 2500 model-based pathways submitted to the AR6 scenarios database pathways explore
33 different possible evolutions of future energy and land use (with and without climate policy) and the
34 consequences for greenhouse gas emissions.
35 From the full range of pathways, five archetype scenarios – referred to in this report as Illustrative
36 Mitigation Pathways (IMPs) – were selected to illustrate key mitigation-strategy themes that flow
37 through several chapters in this report. A further two pathways illustrative of high emissions assuming
38 continuation of current policies or moderately increased action were selected to show the consequences
39 of current policies and pledges. Together these pathways provide illustrations of potential future
40 developments that can be shaped by human choices, including: Where are current policies and pledges
41 leading us? What is needed to reach specific temperature goals? What are the consequences of using
42 different strategies to meet these goals? What are the consequences of delay? How can we shift
43 development from current practices to give higher priority to sustainability and the SDGs?
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Final Government Distribution Technical Summary IPCC AR6 WG III
1 Each of the IMPs comprises: a storyline and a quantitative illustration. The storyline describes the key
2 characteristics of the pathway qualitatively; the quantitative illustration is selected from the literature
3 on long-term scenarios to effectively represent the IMP numerically. The five Illustrative Mitigation
4 Pathways (IMPs) each emphasise a different scenario element as its defining feature, and are named
5 accordingly: heavy reliance on renewables (IMP-Ren), strong emphasis on low demand for energy
6 (IMP-LD), extensive use of Carbon Dioxide Removal (CDR) in the energy and the industry sectors to
7 achieve net negative emissions (IMP-Neg), mitigation in the context of broader sustainable
8 development and shifting development pathways (IMP-SP), and the implications of a less rapid and
9 gradual strengthening of near-term mitigation actions (IMP-GS). In some cases, sectoral chapters may
10 use different quantifications that follow the same storyline narrative but contain data that better
11 exemplify the chapter’s assessment. Some IMP variants are also used to explore the sensitivity around
12 alternative temperature goals. {3.2, 3.3}
13 The two additional pathways illustrative of higher emissions are current policies (CurPol) and moderate
14 action (ModAct).
15 This framework is summarised in Box TS.5 Table.1 below, which also shows where the IMPs are
16 situated with respect to the classification of emissions scenarios into warming levels (C1-C8) introduced
17 in Chapter 3, and the CMIP6 (Coupled Model Intercomparison Project 6) scenarios used in the AR6
18 WG I report.
19
20 Box TS.5 Table.1 Illustrative Mitigation Pathways (IMPs) and pathways illustrative of higher emissions in
21 relation to scenarios’ categories, and CMIP6 scenarios
22
Classification of emissions scenarios Pathways Illustrative mitigation CMIP 6
into warming levels: C1-C8 illustrative of pathways (IMPs) scenarios
higher emissions
C8 (above 4°C) SSP5-8.5
C7 (below 4°C) CurPol SSP3-7.0
C6 (below 3°C) ModAct SSP2-4.5
C5 (below 2.5°C) SSP4-3.7
C4 (below 2°C)
C3 (likely below 2°C) IMP-GS SSP2-2.6
(Sensitivities: Neg; Ren)
C2 (below 1.5°C; large overshoot) IMP-Neg
C1 (below 1.5°C; no or limited IMP-LD SSP1-1.9
overshoot) IMP-Ren
IMP-SP
23
24 The Shared Socioeconomic Pathways (SSPs)
25 First published in 2017, the Shared Socioeconomic Pathways (SSPs) are alternative projections of
26 socio-economic developments that may influence future GHG emissions.
27 The initial set of SSP narratives described worlds with different challenges to mitigation and adaptation:
28 SSP1 (sustainability), SSP2 (middle of the road), SSP3 (regional rivalry), SSP4 (inequality) and SSP5
29 (rapid growth). The SSPs were subsequently quantified in terms of energy, land-use change, and
30 emission pathways for both i) no-climate-policy reference scenarios and ii) mitigation scenarios that
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Final Government Distribution Technical Summary IPCC AR6 WG III
1 follow similar radiative forcing pathways as the Representative Concentration Pathways (RCPs)
2 assessed in AR5 WG I. {3.2.3}
3 Most of the scenarios in the AR6 database are SSP-based. The majority of the assessed scenarios are
4 consistent with SSP2. Using the SSPs permits a more systematic assessment of future GHG emissions
5 and their uncertainties than was possible in AR5. The main emissions drivers across the SSPs include
6 growth in population reaching 8.5-9.7 billion by 2050, and an increase in global GDP of 2.7-4.1% per
7 year between 2015 and 2050. Final energy demand in the absence of any new climate policies is
8 projected to grow to around 480 to 750 EJ yr-1 in 2050 (compared to around 390 EJ in 2015) (medium
9 confidence). The highest emissions scenarios in the literature result in global warming of >5°C by 2100,
10 based on assumptions of rapid economic growth and pervasive climate policy failures. (high confidence)
11 {3.3}
12 END BOX TS.5 HERE
13
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Final Government Distribution Technical Summary IPCC AR6 WG III
1 Table TS.3: GHG, CO2 emissions and warming characteristics of different mitigation pathways submitted to the AR6 scenarios database, and as categorized in the
2 climate assessment. {Table 3.2}
3
Cumulative net- Temperature
GHG emissions reductions
p50 Global Mean Surface Air GHG emissions Cumulative CO2 emissions negative CO2 change 50% Likelihood of staying below Time when specific temeprature levels are reached (with a 50%
from 2019 Emissions milestones
(6,7,8)
(p5-p95) (0) Temperature change Gt CO2-eq/yr (5) Gt CO2 (10) emissions probability (11) (%) (12) probability)
%
Gt CO2 °C
Category (1, 2, 3, net-zero CO2 net-zero GHGs (9)
WG1 SSP & 2020 to year of net-zero at peak
4) Category description 2030 2040 2050 2030 2040 2050 Peak CO2 emissions Peak GHG emissions [% net-zero [% net-zero 2020-2100 2100 <1.5°C <2.0°C <3.0°C 1.5°C 2.0°C 3.0°C
IPs alignment netzero CO2 CO2 to 2100 warming
[# pathways] pathways] pathways]
SP, LD 31 17 9 43 69 84 2020-2025 [100%] 2020-2025 [100%] 2050-2055 [100%] 2095-2100 [52%] 510 320 -200 1.6 1.3 38 90 100 2030-2035 [90%] ...-... [0%] ...-... [0%]
C1 [97] Below 1.5°C with no or limited overshoot
Ren, SSP1-1.9 (21-36) (6-23) (1-15) (34-60) (58-90) (73-98) (2020-2025) (2020-2025) (2035-2070) (2050-...) (330-710) (-210-570) (-560-0) (1.3-1.6) (0.8-1.5) (33-73) (86-98) (99-100) (2030-...) (...-...) (...-...)
42 25 14 23 55 75 2020-2025 [100%] 2020-2025 [100%] 2055-2060 [100%] 2070-2075 [87%] 720 400 -330 1.7 1.4 24 82 100 2030-2035 [100%] ...-... [0%] ...-... [0%]
C2 [133] Below 1.5°C with high overshoot
(31-55) (16-34) (5-21) (0-44) (40-71) (62-91) (2020-2030) (2020-2030) (2045-2070) (2055-...) (540-930) (-90-620) (-620--30) (1.4-1.8) (0.8-1.5) (15-58) (71-95) (99-100) (2030-2035) (...-...) (...-...)
Neg
SSP2-2.6 44 29 20 21 46 64 2020-2025 [100%] 2020-2025 [100%] 2070-2075 [91%] ...-... [30%] 890 800 -40 1.7 1.6 20 76 99 2030-2035 [100%] ...-... [0%] ...-... [0%]
C3 [311] Likely below 2°C
(32-55) (20-36) (13-26) (1-42) (34-63) (53-77) (2020-2030) (2020-2030) (2060-...) (2075-...) (640-1160) (500-1140) (-280-0) (1.4-1.8) (1.1-1.8) (13-66) (68-97) (98-100) (2030-2040) (...-...) (...-...)
40 29 20 27 47 63 2020-2025 [100%] 2020-2025 [100%] 2075-2080 [88%] …-... [24%] 860 790 -10 1.7 1.6 21 78 100 2030-2035 [100%] ...-... [0%] ...-... [0%]
C3a [204] Immediate action
(30-49) (21-36) (13-26) (13-45) (35-63) (52-76) (2020-2025) (2020-2025) (2060-...) (2080-..) (640-1180) (480-1150) (-280-0) (1.4-1.8) (1.1-1.8) (14-70) (69-97) (98-100) (2030-2040) (...-...) (...-...)
GS 52 29 18 5 46 68 2020-2025 [100%] 2020-2025 [100%] 2065-2070 [96%] …-... [42%] 910 800 -70 1.8 1.6 17 73 99 2030-2035 [100%] ...-... [0%] ...-... [0%]
C3b [97] NDCs
(47-55) (20-36) (10-25) (0-14) (34-63) (56-82) (2020-2030) (2020-2030) (2060-2100) (2075-...) (720-1150) (560-1050) (-300-0) (1.4-1.8) (1.1-1.7) (12-61) (67-96) (98-99) (2030-2035) (...-...) (...-...)
50 38 28 10 31 49 2020-2025 [100%] 2020-2025 [100%] 2075-2080 [86%] ...-... [31%] 1210 1160 -30 1.9 1.8 11 59 98 2030-2035 [100%] ...-... [0%] ...-... [0%]
C4 [159] Below 2°C
(41-56) (28-43) (19-35) (0-27) (20-50) (35-65) (2020-2030) (2020-2030) (2065-...) (2075-...) (970-1500) (700-1490) (-390-0) (1.5-2.0) (1.2-2.0) (7-50) (50-93) (95-99) (2030-2035) (...-...) (...-...)
52 45 39 6 18 29 2020-2025 [100%] 2020-2025 [100%] …-... [40%] ...-... [11%] 1780 1780 0 2.2 2.1 4 37 91 2030-2035 [100%] 2060-2065 [99%] ...-... [0%]
C5 [212] Below 2.5°C
(46-56) (36-52) (30-49) (-1-18) (4-33) (11-48) (2020-2035) (2020-2035) (2075-...) (2090-...) (1400-2360) (1260-2360) (-140-0) (1.6-2.5) (1.5-2.5) (0-28) (18-84) (83-99) (2030-2035) (2055-2095) (...-...)
SSP2-4.5 54 53 52 2 3 5 2030-2035 [96%] 2030-2035 [96%] ...-... [0%] ...-... [0%] 2790 2790 0 2.7 2.7 0 8 71 2030-2035 [100%] 2050-2055 [100%] ...-... [0%]
C6 [97] Below 3°C
Mod-Act (50-62) (48-61) (45-57) (-10-11) (-14-14) (-2-18) (2020-2085) (2020-2085) (...-...) (...-...) (2440-3520) (2440-3520) (0-0) (2.0-2.9) (2.0-2.9) (0-2) (2-45) (53-96) (2030-2035) (2045-2060) (...-...)
SSP3-7.0 62 67 70 -11 -19 -24 2070-2075 [56%] 2070-2075 [56%] ...-... [0%] ...-... [0%] 4220 4220 0 3.5 3.5 0 0 22 2030-2035 [100%] 2045-2050 [100%] 2080-2085 [100%]
C7 [164] Below 4°C
Cur-Pol (53-69) (56-76) (58-83) (-18-3) (-31-0) (-41--2) (2025-2095) (2025-2095) (...-...) (...-...) (3160-5000) (3160-5000) (0-0) (2.5-3.9) (2.5-3.9) (0-0) (0-5) (7-80) (2030-2035) (2045-2055) (2070-2100)
SSP5-8.5 71 79 87 -20 -35 -46 2080-2085 [89%] 2080-2085 [89%] ...-... [0%] ...-... [0%] 5600 5600 0 4.2 4.2 0 0 4 2030-2035 [100%] 2040-2045 [100%] 2065-2070 [100%]
C8 [29] Above 4°C
(68-80) (77-96) (82-112) (-34--17) (-66--29) (-92--36) (2060-2095) (2060-2095) (...-...) (...-...) (4910-7450) (4910-7450) (0-0) (3.3-5.0) (3.3-5.0) (0-0) (0-0) (0-27) (2025-2035) (2040-2050) (2060-2075)
4
5
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Final Government Distribution Technical Summary IPCC AR6 WG III
1 Table TS.3 legend: 0 Values in the table refer to the 50th and (5th-95th) percentile values. For emissions-related
2 columns this relates to the distribution of all the pathways in that category. For Temperature Change and
3 Likelihood columns, single upper row values are the 50th percentile value across pathways in that Category for
4 the MAGICC climate model emulator. For the bracketed ranges, the median warming for every pathway in that
5 category is calculated for each of the three climate model emulators (MAGICC, FaIR and CICERO-SCM).
6 Subsequently, the 5th and 95th percentile values across all pathways is calculated. The coolest and warmest
7 outcomes (i.e. the lowest p5 of three emulators, and the highest p95, respectively) are shown in the brackets. Thus
8 these ranges cover the extent of pathway and climate model emulator uncertainty.
9 1 Category definitions consider at-peak warming and warming at the end-of-century (2100).
10 C1: Below 1.5°C in 2100 with a greater than 50% probability and a peak warming higher than 1.5°C with less
11 than 67% probability.
12 C2: Below 1.5°C in 2100 with a greater than 50% probability but peak warming higher than 1.5°C with a
13 probability of 67% or greater.
14 C3: Likely below 2 °C throughout the century with a probability of 67% or greater.
15 C4, C5, C6, C7: Below 2 °C, 2.5 °C, 3 °C and 4 °C throughout the century, respectively, with greater than 50%
16 probability.
17 C8: Peak warming above 4 °C with greater than 50% probability.
18 2 All warming levels are relative to 1850-1900.
19 3 The warming profile of the IMP-Neg peaks around 2060 and declines to below 1.5°C (50% likelihood) shortly
20 after 2100. Whilst technically classified as a C3, it strongly exhibits the characteristics of C2 high overshoot
21 pathways, hence it is placed under C2 category.
22 4 C3 pathways are sub-categorized according to policy ambition and consistent with Figure SPM 6. Two pathways
23 derived from a cost-benefit analysis have been added to C3a, whilst 10 pathways with specifically designed near-
24 term action until 2030 that fall below or above NDCs levels are not included in either of the two subclasses.
25 5 Percentage GHG reduction ranges shown here are calculated relative to the modelled 2019 emissions based on
26 the harmonized and infilled projections from the models (Annex III, section II.2.5). Negative values (e.g. in C7,
27 C8) represent an increase in emissions.
28 6 Percentage (%) reductions and emissions milestones are based on model data for CO 2 & GHG emissions, which
29 has been harmonized to 2015 values. See also Footnote 9.
30 7 The first year range refers to the five year period within which the median peak emissions year or net zero year
31 falls. The second year range refers to the full range (rounded to the nearest five years) within which the 5 th and
32 95th percentiles fall.
33 8 Percentiles reported across all pathways in that category including pathways that do not reach net zero before
34 2100 (fraction of pathways reaching net zero is given in square brackets). If the fraction of pathways that reach
35 net zero before 2100 is lower than the fraction of pathways covered by a percentile (e.g. 0.95 for the 95th
36 percentile), the percentile is not defined and denoted with "…". Fraction of pathways reaching net zero is
37 calculated based on the native model emissions profiles.
38 9 For cases where models do not report all GHGs, missing GHG species are infilled and calculated as Kyoto
39 basket in CO2-eq using AR6 GWP100. For each pathway, a minimum of native reporting of CO 2, CH4, and N2O
40 emissions was required for the assessment of the climate response and assignment to a climate category. Emissions
41 pathways without climate assessment are not included in the ranges presented here. See Annex III for details.
42 10 For better comparability with the WG I assessment of the remaining carbon budget, the cumulative GHG
43 emissions of the pathways are harmonized to the 2015 CO2 emissions levels used in the WG I assessment and are
44 calculated for the future starting in 1 January 2020.
45 11 Temperature change (Global Surface Air Temperature - GSAT) for category (at peak and in 2100), based on
46 the median warming for each pathway assessed using the probabilistic climate model emulators.
47 12 Probability of staying below the temperature thresholds for the pathways in each category, taking into
48 consideration the range of uncertainty from the climate model emulators consistent with the WG I AR6
49 assessment. The probabilities refer to the probability at peak temperature. Note that in the case of temperature
50 overshoot (E.g., category C2 and some pathways in C1), the probabilities at the end of the century are higher than
51 the probability at peak temperature.
52 Pathways following current NDCs until 2030 reach annual emissions of 47-57 GtCO2-eq yr-1 by
53 2030, thereby making it impossible to limit warming to 1.5°C with no or limited overshoot and
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Final Government Distribution Technical Summary IPCC AR6 WG III
1 strongly increasing the challenge of likely limiting warming to 2°C (high confidence). A high
2 overshoot of 1.5°C increases the risks from climate impacts and increases dependence on large scale
3 carbon dioxide removal from the atmosphere. A future consistent with current NDCs implies higher
4 fossil fuel deployment and lower reliance on low carbon alternatives until 2030, compared to mitigation
5 pathways describing immediate action that limits warming to 1.5°C with no or limited overshoot, or
6 likely limits warming to 2°C and below. After following the NDCs to 2030, to likely limit warming to
7 2°C the pace of global GHG emission reductions would need to abruptly increase from 2030 onward to
8 an average of 1.3-2.1 GtCO2-eq per year between 2030 and 2050. This is similar to the global CO2
9 emission reductions in 2020 that occurred due to the COVID-19 pandemic lockdowns, and around 70%
10 faster than in pathways where immediate action is taken to likely limit warming to 2°C. Accelerating
11 emission reductions after following an NDC pathway to 2030 would also be particularly challenging
12 because of the continued build-up of fossil fuel infrastructure that would take place between now and
13 2030. (TS 4.1, Table TS.3) {3.5, 4.2}
14 Pathways accelerating action compared to current NDCs – that reduce annual GHG emissions to
15 47 (38-51) GtCO2-eq by 2030 (which is 3-9 GtCO2-eq below projected emissions from fully
16 implementing current NDCs) – make it less challenging to likely limit warming to 2°C after 2030
17 (medium confidence). The accelerated action pathways are characterized by a global, but regionally
18 differentiated, roll-out of regulatory and pricing policies. Compared to current NDCs, they describe less
19 fossil fuel use and more low-carbon fuel use until 2030; they narrow, but do not close the gap to
20 pathways that assume immediate global action using all available least-cost abatement options. All
21 delayed or accelerated action pathways likely limiting warming to below 2°C converge to a global
22 mitigation regime at some point after 2030 by putting a significant value on reducing carbon and other
23 GHG emissions in all sectors and regions. {3.5}
24 In mitigation pathways, peak warming is determined by the cumulative net CO2 emissions until
25 the time of net zero CO2 together with the warming contribution of other GHGs and climate
26 forcers at that time (high confidence). Cumulative net CO2 emissions from 2020 to the time of net
27 zero CO2 are 510 (330-710) GtCO2 in pathways that limit warming to 1.5°C with no or limited overshoot
28 and 890 (640-1160) GtCO2 in pathways likely limiting warming to 2.0°C. These estimates are consistent
29 with the AR6 WG I assessment of remaining carbon budgets adjusting for methodological differences
30 and non-CO2 warming. {3.3, Box 3.4}
31 Rapid reductions in non-CO2 GHGs, particularly CH4, would lower the level of peak warming
32 (high confidence). Non-CO2 emissions – at the time of reaching net zero CO2 – range between 4-11
33 GtCO2-eq yr-1 in pathways likely limiting warming to 2.0°C or below. CH4 is reduced by around 20%
34 (1-46%) in 2030 and almost 50% (26-64%) in 2050, relative to 2019. CH4 emission reductions in
35 pathways limiting warming to 1.5°C with no or limited overshoot are substantially higher by 2030, 33%
36 (19-57%), but only moderately so by 2050, 50% (33-69%). CH4 emissions reductions are thus attainable
37 at comparatively low costs, but, at the same time, reductions are limited in scope in most 1.5-2°C
38 pathways. Deeper CH4 emissions reductions by 2050 could further constrain the peak warming. N2O
39 emissions are also reduced, but similar to CH4, N2O emission reductions saturate for more stringent
40 climate goals. The emissions of cooling aerosols in mitigation pathways decrease as fossil fuels use is
41 reduced. The overall impact on non-CO2-related warming combines all these factors. {3.3}
42 Net zero GHG emissions imply net negative CO2 emissions at a level that compensates for residual
43 non-CO2 emissions. Only 30% of the pathways likely limiting warming to 2°C or below reach net
44 zero GHG emissions in the 21st century (high confidence). In those pathways reaching net zero
45 GHGs, net zero GHGs is achieved around 10-20 years later than net zero CO2 is achieved (medium
46 confidence). The reported quantity of residual non-CO2 emissions depends on accounting choices, and
47 in particular the choice of GHG metric (Box TS.2). Reaching and sustaining global net zero GHG
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Final Government Distribution Technical Summary IPCC AR6 WG III
1 emissions – when emissions are measured and reported in terms of GWP100 – results in a gradual
2 decline in temperature (high confidence). (Box TS.6) {3.3}
3
4
5
6 Figure TS.10: Mitigation pathways that limit warming to 1.5°C, or 2°C, involve deep, rapid and sustained
7 emissions reductions. Net zero CO2 and net zero GHG emissions are possible through different mitigation
8 portfolios
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1 Figure TS.10 legend: Panel a shows the development of global CO2 emissions (upper sub-panel) and timing of
2 when emissions from different sources reach net zero CO 2 and GHG emissions (lower sub-panel). Panels b and
3 c show the development of global CH4 and N2O emissions, respectively. Ranges of baseline emissions pathways
4 (red), 2050), however, requires more rapid and
8 deeper near-term emissions reductions (in 2030 and 2040) if warming is to be limited to the same level.
9 *Note: in this assessment the terms net zero CO2 emissions and carbon neutrality have different meanings and are
10 only equivalent at the global scale. At the scale of regions, or sectors, each term applies different system
11 boundaries. This is also the case for the related terms net zero GHG and GHG neutrality. {Cross-Chapter Box 3
12 in Chapter 3}
13 END BOX TS.6 HERE
14
15
16
17
18
19
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1 START BOX TS.7 HERE
2 Box TS.7 The Long-term Economic Benefits of Mitigation from Avoided Climate Change
3 Impacts
4 Integrated studies use either a cost-effectiveness analysis (CEA) approach (minimising the total
5 mitigation costs of achieving a given policy goal) or a cost-benefit analysis (CBA) approach
6 (balancing the cost and benefits of climate action). In the majority of studies that have produced the
7 body of work on the cost of mitigation assessed in this report, a CEA approach is adopted, and the
8 feedbacks of climate change impacts on the economic development pathways are not accounted for.
9 This omission of climate impacts leads to overly optimistic economic projections in the reference
10 scenarios, in particular in reference scenarios with no or limited mitigation action where the extent of
11 global warming is the greatest. Mitigation cost estimates computed against no or limited policy
12 reference scenarios therefore omit economic benefits brought by avoided climate change impact along
13 mitigation pathways. {1.7, 3.6.1}
14 The difference in aggregate economic impacts from climate change between two given temperature
15 levels represents the aggregate economic benefits arising from avoided climate change impacts due to
16 mitigation action. Estimates of these benefits vary widely, depending on the methodology used and
17 impacts included, as well as on assumed socioeconomic development conditions, which shape exposure
18 and vulnerability. The aggregate economic benefits of avoiding climate impacts increase with the
19 stringency of the mitigation. Global economic impact studies with regional estimates find large
20 differences across regions, with developing and transitional economies typically more vulnerable.
21 Furthermore, avoided impacts for poorer households and poorer countries represent a smaller share in
22 aggregate quantifications expressed in GDP terms or monetary terms, compared to their influence on
23 well-being and welfare (high confidence). {3.6.2, Cross-Working Group Box 1 in Chapter 3}
24 CBA analysis and CBA integrated assessment models remain limited in their ability to represent all
25 damages from climate change, including non-monetary damages, and capture the uncertain and
26 heterogeneous nature of damages and the risk of catastrophic damages, such that other lines of evidence
27 should be considered in decision-making. However, emerging evidence suggests that, even without
28 accounting for co-benefits of mitigation on other sustainable development dimensions, the global
29 benefits of pathways likely to limit warming to 2°C outweigh global mitigation costs over the 21st
30 century (medium confidence). Depending on the study, the reason for this result lies in assumptions of
31 economic damages from climate change in the higher end of available estimates, in the consideration
32 of risks of tipping-points or damages to natural capital and non-market goods, or in the combination of
33 updated representations of carbon cycle and climate modules, updated damage estimates and updated
34 representations of economic and mitigation dynamics. In the studies that perform a sensitivity analysis,
35 this result is found to be robust to a wide range of assumptions on social preferences (in particular on
36 inequality aversion and pure rate of time preference), and holds except if assumptions of economic
37 damages from climate change are in the lower end of available estimates and the pure rate of time
38 preference is in the higher range of values usually considered (typically above 1.5%). However,
39 although such pathways bring overall net benefits over time (in terms of aggregate discounted present
40 value), they involve distributional consequences between and within generations. {3.6.2}
41 END BOX TS.7 HERE
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1 TS. 5 Mitigation responses in sectors and systems
2 Chapters 5-12 assess recent advances in knowledge in individual sectors and systems. These chapters
3 – Energy (Chapter 6), Urban and other settlements (Chapter 8), Transport (Chapter 10), Buildings
4 Chapter 9), Industry (Chapter 11), and Agriculture, forestry and other land use (AFOLU) (Chapter 7) –
5 correspond broadly to the IPCC National Greenhouse Gas Inventory reporting categories and build on
6 similar chapters in previous WG III reports. Chapters 5 and 12 tie together the cross-sectoral aspects of
7 this group of chapters including the assessment of costs and potentials, demand side aspects of
8 mitigation, and carbon dioxide removal (CDR).
9 TS. 5.1 Energy
10 A broad-based approach to deploying energy sector mitigation options can reduce emissions over
11 the next ten years and set the stage for still deeper reductions beyond 2030 (high confidence).
12 There are substantial, cost-effective opportunities to reduce emissions rapidly, including in electricity
13 generation, but near-term reductions will not be sufficient to likely limit warming to 2°C or limit
14 warming to 1.5°C with no or limited overshoot. {6.4, 6.6, 6.7}
15 Warming cannot be limited to 2°C or 1.5°C without rapid and deep reductions in energy system
16 CO2 and GHG emissions (high confidence). In scenarios likely limiting warming to 1.5°C with no or
17 limited overshoot (likely below 2°C), net energy system CO2 emissions (interquartile range) fall by 87%
18 to 97%% (60% to 79%) in 2050. In 2030, in scenarios limiting warming to 1.5°C with no or limited
19 overshoot, net CO2 and GHG emissions fall by 35-51% and 38-52% respectively. In scenarios limiting
20 warming to 1.5°C with no or limited overshoot (likely below 2°C), net electricity sector CO2 emissions
21 reach zero globally between 2045 and 2055 (2050 and 2080) (high confidence). {6.7}
22 Limiting warming to 2°C or 1.5°C will require substantial energy system changes over the next
23 30 years. This includes reduced fossil fuel consumption, increased production from low- and zero-
24 carbon energy sources, and increased use of electricity and alternative energy carriers (high
25 confidence). Coal consumption without CCS falls by 67% to 82% (interquartile range) in 2030 in
26 scenarios limiting warming to 1.5°C with no or limited overshoot. Oil and gas consumption fall more
27 slowly. Low-carbon sources produce 93% to 97% of global electricity by 2050 in scenarios that likely
28 limit warming to 2°C or below. In scenarios limiting warming to 1.5°C with no or limited overshoot
29 (likely below 2°C), electricity supplies 48% to 58% (36% to 47%) of final energy in 2050, up from 20%
30 in 2019. {6.7}
31 Net zero energy systems will share common characteristics, but the approach in every country
32 will depend on national circumstances (high confidence). Common characteristics of net-zero energy
33 systems will include: (1) electricity systems that produce no net CO2 or remove CO2 from the
34 atmosphere; (2) widespread electrification of end uses, including light-duty transport, space heating,
35 and cooking; (3) substantially lower use of fossil fuels than today; (4) use of alternative energy carriers
36 such as hydrogen, bioenergy, and ammonia to substitute for fossil fuels in sectors less amenable to
37 electrification; (5) more efficient use of energy than today; (6) greater energy system integration across
38 regions and across components of the energy system; and (7) use of CO2 removal including DACCS
39 and BECCS to offset residual emissions. {6.6}
40 Energy demands and energy sector emissions have continued to rise (high confidence). From 2015
41 to 2019, global final energy consumption grew by 6.6%, CO2 emissions from the global energy system
42 grew by 4.6%, and total GHG emissions from energy supply rose by 2.7%. Fugitive CH4 emissions
43 from oil, gas, and coal, accounted for 5.8% of GHG emissions in 2019. Coal electricity capacity grew
44 by 7.6% between 2015 and 2019, as new builds in some countries offset declines in others. Total
45 consumption of oil and oil products increased by 5%, and natural gas consumption grew by 15%.
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1 Declining energy intensity in almost all regions has been balanced by increased energy consumption.
2 {6.3}
3 The unit costs for several key energy system mitigation options have dropped rapidly over the
4 last five years, notably solar PV, wind power, and batteries (high confidence). From 2015 to 2020,
5 the costs of electricity from PV and wind dropped 56% and 45%, respectively, and battery prices
6 dropped by 64%. Electricity from PV and wind is now cheaper than electricity from fossil sources in
7 many regions, electric vehicles are increasingly competitive with internal combustion engines, and
8 large-scale battery storage on electricity grids is increasingly viable. (Figure TS.7) {6.3, 6.4}
9 Global wind and solar PV capacity and generation have increased rapidly driven by policy,
10 societal pressure to limit fossil generation, low interest rates, and cost reductions (high
11 confidence). Solar PV grew by 170% (to 680 TWh); wind grew by 70% (to 1420 TWh) from 2015 to
12 2019. Solar PV and wind together accounted for 21% of total low-carbon electricity generation and 8%
13 of total electricity generation in 2019. Nuclear generation grew 9% between 2015 and 2019 and
14 accounted for 10% of total generation in 2019 (2790 TWh); hydroelectric power grew by 10% and
15 accounted for 16% (4290 TWh) of total generation. In total, low- and zero-carbon electricity generation
16 technologies produced 37% of global electricity in 2019. {6.3, 6.4}
17 If investments in coal and other fossil infrastructure continue, energy systems will be locked-in to
18 higher emissions, making it harder to limit warming to 2°C or 1.5°C (high confidence). Many
19 aspects of the energy system – physical infrastructure; institutions, laws, and regulations; and behaviour
20 – are resistant to change or take many years to change. New investments in coal-fired electricity without
21 CCS are inconsistent with limiting warming to 2°C or 1.5°C. {6.3, 6.7}
22 Limiting warming to 2°C or 1.5°C will strand fossil-related assets, including fossil infrastructure
23 and unburned fossil fuel resources (high confidence). The economic impacts of stranded assets could
24 amount to trillions of dollars. Coal assets are most vulnerable over the coming decade; oil and gas assets
25 are more vulnerable toward mid-century. CCS can allow fossil fuels to be used longer, reducing
26 potential stranded assets. (Box TS.8) {6.7}
27
28 START BOX TS.8 HERE
29 Box TS. 8: Stranded Assets
30 Limiting warming to 2°C or 1.5°C is expected to result in the “stranding” of carbon-intensive
31 assets. Stranded assets can be broadly defined as assets which “suffer from unanticipated or premature
32 write-offs, downward revaluations or conversion to liabilities”. Climate policies, other policies and
33 regulations, innovation in competing technologies, and shifts in fuel prices could all lead to stranded
34 assets. The loss of wealth from stranded assets would create risks for financial market
35 stability, reduce fiscal revenue for hydrocarbon dependent economies, in turn affecting macro-
36 economic stability and the prospects for a just transition. (Box TS.4) {6.7, 15.6, Chapter 17}
37 Two types of assets are at risk of being stranded: i) in-ground fossil resources and ii) human-made
38 capital assets (e.g., power plants, cars). About 30% of oil, 50% of gas, and 80% of coal reserves will
39 remain unburnable if warming is limited to 2°C. {6.7, Box 6.11}
40 Practically all long-lived technologies and investments that cannot be adapted to low-carbon and zero-
41 emission modes could face stranding under climate policy – depending on their current age and
42 expected lifetimes. Scenario evidence suggests that without carbon capture, the worldwide fleet of coal-
43 and gas power plants would need to retire about 23 and 17 years earlier than expected lifetimes,
44 respectively in order to limit global warming to 1.5°C and 2°C {2.7}. Blast furnaces and cement
45 factories without CCS {11.4}, new fleets of airplanes and internal combustion engine vehicles {10.4,
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1 10.5}, and new urban infrastructures adapted to sprawl and motorisation may also be stranded
2 {Chapter 8; Box 10.1}.
3 Many countries, businesses, and individuals stand to lose wealth from stranded assets. Countries,
4 businesses, and individuals may therefore desire to keep assets in operation even if financial, social, or
5 environmental concerns call for retirement. This creates political economic risks, including actions by
6 asset owners to hinder climate policy reform {6.7; Box 6.11}. It will be easier to retire these assets
7 if the risks are communicated, if sustainability reporting is mandated and enforced, and if
8 corporations are protected with arrangements that shield them from short-term shareholder value
9 maximisation.
10 Without early retirements, or reductions in utilisation, the current fossil infrastructure will emit more
11 GHGs than is compatible with limiting warming to 1.5°C {2.7}. Including the pipeline of planned
12 investments would push these future emissions into the uncertainty range of 2°C carbon budgets {2.7}.
13 Continuing to build new coal-fired power plants and other fossil infrastructure will increase future
14 transition costs and may jeopardize efforts to likely limit warming to 2°C or 1.5°C with no or limited
15 overshoot. One study has estimated that USD11.8 trillion in current assets will need to be stranded by
16 2050 for 2°C world; further delaying action for another 10 years would result in an additional USD7.7
17 trillion in stranded assets by 2050. {15.5.2}
18 Experience from past stranding indicates that compensation for the devaluation costs of private sector
19 stakeholders by the public sector is common. Limiting new investments in fossil technologies hence
20 also reduces public finance risks in the long term. {15.6.3}
21 END BOX TS.8 HERE
22
23 A low-carbon energy transition will shift investment patterns and create new economic
24 opportunities (high confidence). Total energy investment needs will rise, relative to today, over the
25 next decades, if it is to be likely that warming is limited to 2°C, or if warming is limited to 1.5°C with
26 no or limited overshoot. These increases will be far less pronounced, however, than the reallocations of
27 investment flows that are anticipated across sub-sectors, namely from fossil fuels (extraction,
28 conversion, and electricity generation) without CCS and toward renewables, nuclear power, CCS,
29 electricity networks and storage, and end-use energy efficiency. A significant and growing share of
30 investments between now and 2050 will be made in emerging economies, particularly in Asia. {6.7}
31 Climate change will affect many future local and national low-carbon energy systems. The
32 impacts, however, are uncertain, particularly at the regional scale (high confidence). Climate
33 change will alter hydropower production, bioenergy and agricultural yields, thermal power plant
34 efficiencies, and demands for heating and cooling, and it will directly impact power system
35 infrastructure. Climate change will not affect wind and solar resources to the extent that it would
36 compromise their ability to reduce emissions. {6.5}
37 Electricity systems powered predominantly by renewables will be increasingly viable over the
38 coming decades, but it will be challenging to supply the entire energy system with renewable
39 energy (high confidence). Large shares of variable solar PV and wind power can be incorporated in
40 electricity grids through batteries, hydrogen, and other forms of storage; transmission; flexible non-
41 renewable generation; advanced controls; and greater demand-side responses. Because some
42 applications (e.g., aviation) are not currently amenable to electrification, it is anticipated that 100%
43 renewable energy systems will need to include alternative fuels such as hydrogen or biofuels. Economic,
44 regulatory, social, and operational challenges increase with higher shares of renewable electricity and
45 energy. The ability to overcome these challenges in practice is not fully understood. (Box TS.9) {6.6}
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1 START BOX TS.9 HERE
2
3 Box TS.9: The Transformation in Energy Carriers: Electrification and Hydrogen
4 To use energy, it must be “carried” from where it was produced – at a power plant, for example, or a
5 refinery, or a coal mine – to where it is used. As countries reduce CO2 emissions, they will need to
6 switch from gasoline and other petroleum-based fuels, natural gas, coal, and electricity produced from
7 these fossil fuels to energy carriers with little or no carbon footprint. An important question is which
8 new energy carriers will emerge to support low-carbon transitions.
9 Low-carbon energy systems are expected to rely heavily on end-use electrification, where electricity
10 produced with low GHG emissions is used for building and industrial heating, transport and other
11 applications that rely heavily on fossil fuels at present. But not all end-uses are expected to be
12 commercially electrifiable in the short to medium term {11.3.5}, and many will require low GHG liquid
13 and gaseous fuels, i.e., hydrogen, ammonia, and biogenic and synthetic low GHG hydrocarbons made
14 from low GHG hydrogen, oxygen and carbon sources (the latter from CCU16, biomass, or direct air
15 capture {11.3.6}). The future role of hydrogen and hydrogen derivatives will depend on how quickly
16 and how far production technology improves, i.e. from electrolysis (“green”), biogasification, and fossil
17 fuel reforming with CCS (“blue”) sources. As a general rule, and across all sectors, it is more efficient
18 to use electricity directly and avoid the progressively larger conversion losses from producing hydrogen,
19 ammonia, or constructed low GHG hydrocarbons. What hydrogen does do, however, is add time and
20 space option value to electricity produced using variable clean sources, for use as hydrogen, as stored
21 future electricity via a fuel cell or turbine, or as an industrial feedstock. Furthermore, electrification and
22 hydrogen involve a symbiotic range of general-purpose technologies, such as electric motors, power
23 electronics, heat pumps, batteries, electrolysis, fuel cells etc., that have different applications across
24 sectors but cumulative economies of innovation and production scale benefits. Finally, neither
25 electrification nor hydrogen produce local air pollutants at point of end-use.
26 For almost 140 years we have primarily produced electricity by burning coal, oil, and gas to drive steam
27 turbines connected to electricity generators. When switching to low-carbon energy sources – renewable
28 sources, nuclear power, and fossil or bioenergy with CCS – electricity is expected to become a more
29 pervasive energy carrier. Electricity is a versatile energy carrier, with much higher end-use efficiencies
30 than fuels, and it can be used directly to avoid conversion losses.
31 An increasing reliance on electricity from variable renewable sources, notably wind and solar power,
32 disrupts old concepts and makes many existing guidelines obsolete for power system planning, e.g.,
33 that specific generation types are needed for baseload, intermediate load, and peak load to follow and
34 meet demand. In future power systems with high shares of variable electricity from renewable sources,
35 system planning and markets will focus more on demand flexibility, grid infrastructure and
36 interconnections, storage on various timelines (on the minute, hourly, overnight and seasonal scale),
37 and increased coupling between the energy sector and the building, transport and industrial sectors. This
38 shifts the focus to energy systems that can handle variable supply rather than always follow demand.
39 Hydrogen may prove valuable to improve the resilience of electricity systems with high penetration of
40 variable renewable electricity. Flexible hydrogen electrolysis, hydrogen power plants and long-duration
41 hydrogen storage may all improve resilience. Electricity-to-hydrogen-to-electricity round-trip
42 efficiencies are projected to reach up to 50% by 2030. {6.4.3}
FOOTNOTE16 Carbon dioxide capture and utilisation (CCU) refers to a process in which CO2 is captured and the
carbon is then used in a product. The climate effect of CCU depends on the product lifetime, the product it
displaces, and the CO2 source (fossil, biomass or atmosphere). CCU is sometimes referred to as Carbon Dioxide
Capture and Use, or Carbon Capture and Utilisation.
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1 Electrification is expected to be the dominant strategy in buildings as electricity is increasingly used for
2 heating and for cooking. Electricity will help to integrate renewable energy into buildings and will also
3 lead to more flexible demand for heating, cooling, and electricity. District heating and cooling offers
4 potential for demand flexibility through energy storage and supply flexibility through cogeneration.
5 Heat pumps are increasingly used in buildings and industry for heating and cooling {9.3.3, Box 9.3}.
6 The ease of switching to electricity means that hydrogen is not expected to be a dominant pathway for
7 buildings {Box 9.6}. Using electricity directly for heating, cooling and other building energy demand
8 is more efficient than using hydrogen as a fuel, for example, in boilers or fuel cells. In addition,
9 electricity distribution is already well developed in many regions compared to essentially non-existent
10 hydrogen infrastructure, except for a few chemicals industry pipelines. At the same time, hydrogen
11 could potentially be used for on-site storage should technology advance sufficiently.
12 Electrification is already occurring in several modes of personal and light freight transport, and vehicle-
13 to-grid solutions for flexibility have been extensively explored in the literature and small-scale pilots.
14 The role of hydrogen in transport depends on how far technology develops. Batteries are currently a
15 more attractive option than hydrogen and fuel-cells for light-duty vehicles. Hydrogen and hydrogen-
16 derived synthetic fuels, such as ammonia and methanol, may have a more important role in heavy
17 vehicles, shipping, and aviation {10.3}. Current transport of fossil fuels may be replaced by future
18 transport of hydrogen and hydrogen carriers such as ammonia and methanol, or energy intensive basic
19 materials processed with hydrogen (e.g. reduced iron) in regions with bountiful renewable resources.
20 {Box 11.1}
21 Both light and heavy industry are potentially large and flexible users of electricity for both final energy
22 use (e.g., directly and using heat pumps in light industry) and for feedstocks (e.g., hydrogen for steel
23 making and chemicals). For example, industrial process heat demand, ranging from below 100°C to
24 above 1000 °C, can be met through a wide range of electrically powered technologies instead of using
25 fuels. Future demand for hydrogen (e.g., for nitrogen fertiliser or as reduction agent in steel production)
26 also offers electricity demand flexibility for electrolysis through hydrogen storage and flexible
27 production cycles {11.3.5}. The main use of hydrogen and hydrogen carriers in industry is expected to
28 be as feedstock (e.g., for ammonia and organic chemicals) rather than for energy as industrial
29 electrification increases.
30 END BOX TS.9 HERE
31
32 Multiple energy supply options are available to reduce emissions over the next decade (high
33 confidence). Nuclear power and hydropower are already established technologies. Solar PV and wind
34 are now cheaper than fossil-generated electricity in many locations. Bioenergy accounts for about a
35 tenth of global primary energy. Carbon capture is widely used in the oil and gas industry, with early
36 applications in electricity production and biofuels. It will not be possible to widely deploy all of these
37 and other options without efforts to address the geophysical, environmental-ecological, economic,
38 technological, socio-cultural, and institutional factors that can facilitate or hinder their implementation.
39 (high confidence). (Figure TS.11, Figure TS.31) {6.4}
40 Enhanced integration across energy system sectors and across scales will lower costs and facilitate
41 low-carbon energy system transitions (high confidence). Greater integration between the electricity
42 sector and end use sectors can facilitate integration of variable renewable energy options. Energy
43 systems can be integrated across district, regional, national, and international scales (high confidence).
44 {6.4, 6.6}
45 The viable speed and scope of a low-carbon energy system transition will depend on how well it
46 can support SDGs and other societal objectives (high confidence). Energy systems are linked to a
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1 range of societal objectives, including energy access, air and water pollution, health, energy security,
2 water security, food security, economic prosperity, international competitiveness, and employment.
3 These linkages and their importance vary among regions. Energy sector mitigation and efforts to
4 achieve SDGs generally support one another, though there are important region-specific exceptions.
5 (high confidence). (Figure TS.29) {6.1, 6.7}
6 The economic outcomes of low-carbon transitions in some sectors and regions may be on par with,
7 or superior to those of an emissions-intensive future (high confidence). Cost reductions in key
8 technologies, particularly in electricity and light-duty transport, have increased the economic
9 attractiveness of near-term low-carbon transitions. Long-term mitigation costs are not well understood
10 and depend on policy design and implementation, and the future costs and availability of technologies.
11 Advances in low-carbon energy resources and carriers such as next-generation biofuels, hydrogen
12 produced from electrolysis, synthetic fuels, and carbon-neutral ammonia would substantially improve
13 the economics of net zero energy systems (medium confidence). {6.4, 6.7}
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1
2
Panel a: flows within the 2019 global energy system
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1
Panel b: flows withing an illustrative future net zero CO2 emissions global energy system
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1
2 Panel c: flows within an illustrative future net zero CO2 emissions global energy system
3 Figure TS.11 Global energy flows within the 2019 global energy system (panel a) and within two illustrative futures, net zero CO2 emissions global energy
4 systems (panels b and c)
5 Figure TS.11 legend: Flows below 1 EJ are not represented, rounded figures. The illustrative net zero scenarios correspond to the year in which net energy system CO 2
6 emissions reach zero {Figure 6.1}
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1 TS. 5.2 Urban and other settlements
2 Although urbanisation is a global trend often associated with increased incomes and higher
3 consumption, the growing concentration of people and activities is an opportunity to increase
4 resource efficiency and decarbonise at scale (very high confidence). The same urbanisation level can
5 have large variations in per capita urban carbon emissions. For most regions, per capita urban emissions
6 are lower than per capita national emissions (very high confidence). {8.1.4, 8.3.3, 8.4, Box 8.1}
7 Most future urban population growth will occur in developing countries, where per capita
8 emissions are currently low but are expected to increase with the construction and use of new
9 infrastructure and the built environment, and changes in incomes and lifestyles (very high
10 confidence). The drivers of urban GHG emissions are complex and include an interplay of population
11 size, income, state of urbanisation, and how cities are laid out. How new cities and towns are designed,
12 constructed, managed, and powered will lock-in behaviour, lifestyles, and future urban GHG emissions.
13 Urban strategies can improve well-being while minimising impact on GHG emissions. However,
14 urbanisation can result in increased global GHG emissions through emissions outside the city’s
15 boundaries (very high confidence). {8.1.4, 8.3, Box 8.1, 8.4, 8.6}
16 The urban share of combined global (CO2 and CH4 emissions is substantial and continues to
17 increase (high confidence). Urban areas generated between 67–72% (~28 GtCO2-eq) of combined
18 global CO2 and CH4 emissions in 2020 through the production and consumption of goods and services.
19 These emissions are projected to rise to 34–65 GtCO2-eq by 2050 with moderate to no mitigation efforts,
20 driven by a growing population, infrastructure, and service demands in urban areas. About 100 of the
21 highest emitting urban areas account for approximately 18% of the global carbon footprint (high
22 confidence). {8.1.6, 8.3.3}
23 The urban share of regional GHG emissions increased between 2000 and 2015, with much inter-
24 regional variation in the magnitude of the increase (high confidence). Globally, the urban share of
25 national emissions increased six percentage points, from 56% in 2000 to 62% in 2015. For 2000 to
26 2015, the urban emissions share increased from 28% to 38% in Africa, from 46% to 54% in Asia and
27 Developing Pacific, from 62% to 72% in Developed Countries, from 57% to 62% in Eastern Europe
28 and West-Central Asia, from 55% to 66% in Latin America and Caribbean, and from 68% to 69% in
29 the Middle East (high confidence). {8.1.6, 8.3.3}
30 Per capita urban GHG emissions increased between 2000 and 2015, with cities in developed
31 countries accounting for nearly seven times more per capita than the lowest emitting region
32 (medium confidence). From 2000 to 2015, global urban GHG emissions per capita increased from 5.5
33 to 6.2 tCO2-eq per person (an increase of 11.8%). Emissions in Africa increased from 1.3 to 1.5 tCO2-
34 eq per person (22.6%); in Asia and Developing Pacific from 3.0 to 5.1 tCO2-eq per person (71.7%); in
35 Eastern Europe and West-Central Asia from 6.9 to 9.8 tCO2-eq per person (40.9%); in Latin America
36 and the Caribbean from 2.7 to 3.7 tCO2-eq per person (40.4%); and in the Middle East from 7.4 to 9.6
37 tCO2-eq per person (30.1%). Albeit starting from the highest level, developed countries showed a
38 modest decline of 11.4 to 10.7 tCO2-eq per person (-6.5%). (Figure TS.12) {8.3.3}
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1
2 Figure TS.12 Changes in six metrics associated with urban and national-scale combined CO2 and CH4
3 emissions represented in the WG III AR6 6-region aggregation, with (a) 2000 and (b) 2015
4 Figure TS.12 legend: The total values exclude aviation, shipping, and biogenic sources. The dashed grey line
5 represents the global average urban per capita CO2-eq emissions. The regional urban population share, regional
6 CO2-eq share in total emissions, and national per capita CO2-eq emissions by region are given for comparison.
7 {Figure 8.9}
8
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1 The global share of future urban GHG emissions is expected to increase through 2050 with
2 moderate to no mitigation efforts due to growth trends in population, urban land expansion and
3 infrastructure and service demands, but the extent of the increase depends on the scenario and
4 the scale and timing of urban mitigation action (medium confidence). With aggressive and
5 immediate mitigation policies to limit global warming to 1.5°C by the end of the century, including
6 high levels of electrification, energy and material efficiency, renewable energy preferences, and socio-
7 behavioural responses, urban GHG emissions could approach net zero and reach a maximum of 3
8 GtCO2-eq in 2050. Under a scenario with aggressive but not immediate urban mitigation policies to
9 limit global warming to 2°C, urban emissions could reach 17 GtCO2-eq in 2050. With no urban
10 mitigation efforts, urban emissions could more than double from 2020 levels and reach 65 GtCO2-eq in
11 2050, while being limited to 34 GtCO2-eq in 2050 with only moderate mitigation efforts. (Figure TS.13)
12 {8.3.4}
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1
2
3 Figure TS.13 Panel a: Carbon dioxide equivalent emissions from global urban areas from 1990 to 2100. Urban areas are aggregated to five regional domains;
4 Panel b: Comparison of urban emissions under different urbanisation scenarios (GtCO2-eq yr-1) for different regions {Figure 8.13, Figure 8.14}
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1 Urban land areas could triple between 2015 and 2050, with significant implications for future
2 carbon lock-in (medium confidence). There is a large range in the forecasts of urban land expansion
3 across scenarios and models, which highlights an opportunity to shape future urban development
4 towards low- or net zero GHG emissions. By 2050, urban areas could increase up to 211% over the
5 2015 global urban extent, with the median projected increase ranging from 43% to 106%. While the
6 largest absolute amount of new urban land is forecasted to occur in Asia and Developing Pacific, and
7 in Developed Countries, the highest rate of urban land growth is projected to occur in Africa, Eastern
8 Europe and West-Central Asia, and in the Middle East. Given past trends, the expansion of urban areas
9 is expected to take place on agricultural lands and forests, with implications for the loss of carbon
10 stocks. The infrastructure that will be constructed concomitant with urban land expansion will lock-in
11 patterns of energy consumption that will persist for decades. {8.3.1, 8.3.4, 8.4.1, 8.6}
12 The construction of new, and upgrading of existing, urban infrastructure through 2030 will add
13 to emissions (medium evidence, high agreement). The construction of new and upgrading of existing
14 urban infrastructure using conventional practices and technologies can result in significant increase in
15 CO2 emissions, ranging from 8.5 GtCO2 to 14 GtCO2 annually up to 2030 and more than double annual
16 resource requirements for raw materials to about 90 billion tonnes per year by 2050, up from 40 billion
17 tonnes in 2010. {8.4.1, 8.6}
18 Given the dual challenges of rising urban GHG emissions and future projections of more frequent
19 extreme climate events, there is an urgent need to integrate urban mitigation and adaptation
20 strategies for cities to address climate change (very high confidence). Mitigation strategies can
21 enhance resilience against climate change impacts while contributing to social equity, public health,
22 and human well-being. Urban mitigation actions that facilitate economic decoupling can have positive
23 impacts on employment and local economic competitiveness. {8.2, Cross-Working Group Box 2 in
24 Chapter 8, 8.4}
25 Cities can achieve net zero or near net zero GHG emissions only through deep decarbonisation
26 and systemic transformation (very high confidence). Effective emission reductions in cities entail
27 implementing three broad strategies concurrently: (1) reducing urban energy consumption across all
28 sectors, including through compact and efficient urban forms and supporting infrastructure; (2)
29 electrification and switching to low carbon energy sources; and (3) enhancing carbon uptake and stocks
30 (medium evidence, high agreement). Given the regional and global reach of urban supply chains, a city
31 cannot achieve net zero GHG emissions by only focusing on reducing emissions within its
32 administrative boundaries. {8.1.6, 8.3.4, 8.4, 8.6}
33 Packages of mitigation policies that implement multiple urban-scale interventions can have
34 cascading effects across sectors, reduce GHG emissions outside a city’s administrative
35 boundaries, and reduce emissions more than the net sum of individual interventions, particularly
36 if multiple scales of governance are included (high confidence). Cities have the ability to implement
37 policy packages across sectors using an urban systems approach, especially those that affect key
38 infrastructure based on spatial planning, electrification of the urban energy system, and urban green and
39 blue infrastructure. The institutional capacity of cities to develop, coordinate, and integrate sectoral
40 mitigation strategies within their jurisdiction varies by context, particularly those related to governance,
41 the regulatory system, and budgetary control. {8.4, 8.5, 8.6}
42 Integrated spatial planning to achieve compact and resource-efficient urban growth through co-
43 location of higher residential and job densities, mixed land use, and transit-oriented development
44 could reduce urban energy use between 23-26% by 2050 compared to the business-as-usual
45 scenario (high confidence). Compact cities with shortened distances between housing and jobs, and
46 interventions that support a modal shift away from private motor vehicles towards walking, cycling,
47 and low-emissions shared, or public, transportation, passive energy comfort in buildings, and urban
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1 green infrastructure can deliver significant public health benefits and lower GHG emissions. {8.2, 8.3.4,
2 8.4, 8.6}
3 Urban green and blue infrastructure can mitigate climate change through carbon sinks, avoided
4 emissions, and reduced energy use while offering multiple co-benefits (high confidence). Urban
5 green and blue infrastructure, including urban forests and street trees, permeable surfaces, and green
6 roofs offer potentials to mitigate climate change directly through storing carbon, and indirectly by
7 inducing a cooling effect that reduces energy demand and reducing energy use for water treatment.
8 Globally, urban trees store approximately 7.4 billion tonnes of carbon, and sequester approximately 217
9 million tonnes of carbon annually, although carbon storage is highly dependent on biome. Among the
10 multiple co-benefits of green and blue infrastructure are reducing the urban heat island (UHI) effect and
11 heat stress, reducing stormwater runoff, improving air quality, and improving the mental and physical
12 health of urban dwellers. Many of these options also provide benefits to climate adaptation. {8.2, 8.4.4}
13 The potentials and sequencing of mitigation strategies to reduce GHG emissions will vary
14 depending on a city’s land use and spatial form and its state of urbanisation, whether it is an
15 established city with existing infrastructure, a rapidly growing city with new infrastructure, or
16 an emerging city with infrastructure build-up (medium confidence). The long lifespan of urban
17 infrastructures locks in behaviour and emissions. Urban infrastructures and urban form can enable
18 socio-cultural and lifestyle changes that can significantly reduce carbon footprints. Rapidly growing
19 cities can avoid higher future emissions through urban planning to co-locate jobs and housing to achieve
20 compact urban form, and by leapfrogging to low-carbon technologies. Established cities will achieve
21 the largest GHG emissions savings by replacing, repurposing, or retrofitting the building stock, strategic
22 infilling and densifying, as well as through modal shift and the electrification of the urban energy
23 system. New and emerging cities have unparalleled potential to significantly reduce GHG emissions
24 while achieving high quality of life by creating compact, co-located, and walkable urban areas with
25 mixed land use and transit-oriented design, that also preserve existing green and blue assets. {8.2, 8.4,
26 8.6}
27 With over 880 million people living in informal settlements, there are opportunities to harness
28 and enable informal practices and institutions in cities related to housing, waste, energy, water,
29 and sanitation to reduce resource use and mitigate climate change (low evidence, medium
30 agreement). The upgrading of informal settlements and inadequate housing to improve resilience and
31 well-being offers a chance to create a low-carbon transition. However, there is limited quantifiable data
32 on these practices and their cumulative impacts on GHG emissions. {8.1.4, 8.2.2, Cross-Working Group
33 Box 2 in Chapter 8, 8.3.2, 8.4, 8.6, 8.7}
34 Achieving transformational changes in cities for climate change mitigation and adaptation will
35 require engaging multiple scales of governance, including governments and non-state actors, and
36 in connection with substantial financing beyond sectoral approaches (very high confidence). Large
37 and complex infrastructure projects for urban mitigation are often beyond the capacity of local
38 municipality budgets, jurisdictions, and institutions. Partnerships between cities and international
39 institutions, national and region governments, transnational networks, and local stakeholders play a
40 pivotal role in mobilizing global climate finance resources for a range of infrastructure projects with
41 low-carbon emissions and related spatial planning programs across key sectors. {8.4, 8.5}
42
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1 TS. 5.3 Transport
2 Meeting climate mitigation goals would require transformative changes in the transport sector.
3 In 2019, direct GHG emissions from the transport sector were 8.7 GtCO2-eq (up from 5.0 GtCO2-eq in
4 1990) and accounted for 23% of global energy-related CO2 emissions. 70% of direct transport emissions
5 came from road vehicles, while 1%, 11%, and 12% came from rail, shipping, and aviation, respectively.
6 Emissions from shipping and aviation continue to grow rapidly. Transport-related emissions in
7 developing regions of the world have increased more rapidly than in Europe or North America, a trend
8 that is expected to continue in coming decades. (high confidence) {10.1, 10.5, 10.6}
9 Since AR5 there has been a growing awareness of the need for demand management solutions
10 combined with new technologies, such as the rapidly growing use of electromobility for land
11 transport and the emerging options in advanced biofuels and hydrogen-based fuels for shipping
12 and aviation and in other specific land-based contexts (high confidence). There is a growing need
13 for systemic infrastructure changes that enable behavioural modifications and reductions in demand for
14 transport services that can in turn reduce energy demand. The response to the COVID-19 pandemic has
15 also shown that behavioural interventions can reduce transport-related GHG emissions. For example,
16 COVID-19-based lockdowns have confirmed the transformative value of telecommuting replacing
17 significant numbers of work and personal journeys as well as promoting local active transport. There
18 are growing opportunities to implement strategies that drive behavioural change and support the
19 adoption of new transport technology options. {Chapter 5, 10.2, 10.3, 10.4, 10.8}
20 Changes in urban form, behaviour programs, the circular economy, the shared economy, and
21 digitalisation trends can support systemic changes that lead to reductions in demand for transport
22 services or expands the use of more efficient transport modes (high confidence). Cities can reduce
23 their transport-related fuel consumption by around 25% through combinations of more compact land
24 use and the provision of less car-dependent transport infrastructure. Appropriate infrastructure,
25 including protected pedestrian and bike pathways, can also support much greater localised active
26 travel.17 Transport demand management incentives are expected to be necessary to support these
27 systemic changes. There is mixed evidence of the effect of circular economy initiatives, shared economy
28 initiatives, and digitalisation on demand for transport services (Box TS.14). For example, while
29 dematerialisation can reduce the amount of material that needs to be transported to manufacturing
30 facilities, an increase in online shopping with priority delivery can increase demand for freight transport.
31 Similarly, while teleworking could reduce travel demand, increased ridesharing could increase vehicle-
32 km travelled. {Chapter 1, Chapter 5, 10.2, 10.8}
33 Battery-electric vehicles (BEVs) have lower life cycle greenhouse gas emissions than internal
34 combustion engine vehicles (ICEVs) when BEVs are charged with low carbon electricity (high
35 confidence). Electromobility is being rapidly implemented in micro-mobility (e-autorickshaws, e-
36 scooters, e-bikes), in transit systems, especially buses, and to a lesser degree, in personal vehicles. BEVs
37 could also have the added benefit of supporting grid operations. The commercial availability of mature
38 lithium-ion batteries (LIBs) has underpinned this growth in electromobility. As global battery
39 production increases, unit costs are declining. Further efforts to reduce the GHG footprint of battery
40 production, however, are essential for maximising the mitigation potential of BEVs. The continued
41 growth of electromobility for land transport would entail investments in electric charging and related
42 grid infrastructure. Electromobility powered by low-carbon electricity has the potential to rapidly
43 reduce transport GHG and can be applied with multiple co-benefits, especially in the developing
44 countries. {10.3, 10.4, 10.8}
FOOTNOTE 17 ‘Active travel’ is travel that requires physical effort, for example journeys made by walking or
cycling.
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1 Land-based, long-range, heavy-duty trucks can be decarbonised through battery-electric haulage
2 (including the use of electric road systems), complemented by hydrogen- and biofuel-based fuels
3 in some contexts. These same technologies and expanded use of available electric rail systems can
4 support rail decarbonisation (medium confidence). Initial deployments of battery-electric, hydrogen-
5 and bio-based haulage are underway, and commercial operations of some of these technologies are
6 considered feasible by 2030 (medium confidence). These technologies nevertheless face challenges
7 regarding driving range, capital and operating costs, and infrastructure availability. In particular, fuel
8 cell durability, high energy consumption, and costs continue to challenge the commercialisation of
9 hydrogen-based fuel cell vehicles. Increased capacity for low-carbon hydrogen production would also
10 be essential for hydrogen-based fuels to serve as an emissions reduction strategy (high confidence).
11 (Box TS.15) {10.3, 10.4, 10.8}
12 Decarbonisation options for shipping and aviation still require R&D, though advanced biofuels,
13 ammonia, and synthetic fuels are emerging as viable options (medium confidence). Increased
14 efficiency has been insufficient to limit the emissions from shipping and aviation, and natural gas-based
15 fuels are expected to be inadequate to meet stringent decarbonisation goals for these segments (high
16 confidence). High energy density, low carbon fuels are required, but they have not yet reached
17 commercial scale. Advanced biofuels could provide low carbon jet fuel (medium confidence). The
18 production of synthetic fuels using low-carbon hydrogen with CO2 captured through DACCS/BECCS
19 could provide jet and marine fuels but these options still require demonstration at scale (low confidence).
20 Ammonia produced with low-carbon hydrogen could also serve as a marine fuel (medium confidence).
21 Deployment of these fuels requires reductions in production costs. (Figure TS.14) {10.2, 10.3, 10.4,
22 10.5, 10.6, 10.8}
23 Scenarios from bottom-up and top-down models indicate that, without intervention, CO2
24 emissions from transport could grow in the range of 16% and 50% by 2050 (medium confidence).
25 The scenarios literature projects continued growth in demand for freight and passenger services,
26 particularly in developing countries in Africa and Asia (high confidence). This growth is projected to
27 take place across all transport modes. Increases in demand notwithstanding, scenarios that limit
28 warming to 1.5°C degree with no or limited overshoot suggest that a 59% reduction (42-68%
29 interquartile range) in transport-related CO2 emissions by 2050, compared to modelled 2020 levels is
30 required. While many global scenarios place greater reliance on emissions reduction in sectors other
31 than transport, a quarter of the 1.5°C scenarios describe transport-related CO2 emissions reductions in
32 excess of 68% (relative to modelled 2020 levels) (medium confidence). Illustrative Mitigation Pathways
33 IMP-ren and IMP-LD (TS 4.2) describe emission reductions of 80% and 90% in the transport sector,
34 respectively, by 2050. Transport-related emission reductions, however, may not happen uniformly
35 across regions. For example, transport emissions from the Developed Countries, and Eastern Europe
36 and West-Central Asia countries decrease from 2020 levels by 2050 across all scenarios limiting global
37 warming to 1.5°C by 2100, but could increase in Africa, Asia and developing Pacific (APC), Latin
38 America and Caribbean, and the Middle East in some of these scenarios. {10.7}
39 The scenarios literature indicates that fuel and technology shifts are crucial in reducing carbon
40 emissions to meet temperature goals (high confidence). In general terms, electrification tends to play
41 the key role in land-based transport, but biofuels and hydrogen (and derivatives) could play a role in
42 decarbonisation of freight in some contexts. Biofuels and hydrogen (and derivatives) are expected to be
43 more prominent in shipping and aviation. The shifts towards these alternative fuels must occur
44 alongside shifts towards clean technologies in other sectors. {10.7}
45 There is a growing awareness of the need to plan for the significant expansion of low-carbon
46 energy infrastructure, including low-carbon power generation and hydrogen production, to
47 support emissions reductions in the transport sector (high confidence). Integrated energy planning
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1 and operations that take into account energy demand and system constraints across all sectors (transport,
2 buildings, and industry) offer the opportunity to leverage sectoral synergies and avoid inefficient
3 allocation of energy resources. Integrated planning of transport and power infrastructure would be
4 particularly useful in developing countries where ‘greenfield’ development doesn’t suffer from
5 constraints imposed by legacy systems. {10.3, 10.4, 10.8}
6 The deployment of low-carbon aviation and shipping fuels that support decarbonisation of the
7 transport sector could require changes to national and international governance structures
8 (medium confidence). The UNFCCC does not specifically cover emissions from international shipping
9 and aviation. Reporting emissions from international transport is at the discretion of each country. While
10 the International Civil Aviation Organisation (ICAO) and International Maritime Organisation (IMO)
11 have established emissions reductions targets, only strategies to improve fuel efficiency and demand
12 reductions have been pursued, and there has been minimal commitment to new technologies. {10.5,
13 10.6, 10.7}
14 There are growing concerns about resource availability, labour rights, non-climate
15 environmental impacts, and costs of critical minerals needed for lithium-ion batteries (medium
16 confidence). Emerging national strategies on critical minerals and the requirements from major vehicle
17 manufacturers are leading to new, more geographically diverse mines. The standardisation of battery
18 modules and packaging within and across vehicle platforms, as well as increased focus on design for
19 recyclability are important. Given the high degree of potential recyclability of lithium-ion batteries, a
20 nearly closed-loop system in the future could mitigate concerns about critical mineral issues (medium
21 confidence). {10.3, 10.8}
22 Legislated climate strategies are emerging at all levels of government, and together with pledges
23 for personal choices, could spur the deployment of demand and supply-side transport mitigation
24 strategies (medium confidence). At the local level, legislation can support local transport plans that
25 include commitments or pledges from local institutions to encourage behaviour change by adopting an
26 organisational culture that motivates sustainable behaviour with inputs from the creative arts. Such
27 institution-led mechanisms could include bike-to-work campaigns, free transport passes, parking
28 charges, or eliminating car benefits. Community-based solutions like solar sharing, community
29 charging, and mobility as a service can generate new opportunities to facilitate low-carbon transport
30 futures. At the regional and national levels, legislation can include vehicle and fuel efficiency standards,
31 R&D support, and large-scale investments in low-carbon transport infrastructure. (Figure TS.14) {10.8,
32 Chapter 15}
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1
2 Figure TS.14: Mitigation Options and Enabling Conditions for Transport. ‘Niche’ scale includes
3 strategies that still require innovation. {Figure 10.22}
4 ASI: Avoid Shift, Improve; TRL: Technology readiness level
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1 TS. 5.4 Buildings
2 Global GHG emissions from buildings were 12 GtCO2-eq in 2019, equivalent to 21% of global
3 GHG emissions. Of this, 57% (6.8 GtCO2-eq) were indirect emissions from offsite generation of
4 electricity and heat, 24% (2.9 GtCO2-eq) direct emissions produced onsite and 18% (2.2 GtCO2-
5 eq) were embodied emissions from the production of cement and steel used in buildings (high
6 confidence). Most building sector emissions are CO2. Final energy demand from buildings reached 128
7 EJ globally in 2019 (around 31% of global final energy demand), and electricity demand from buildings
8 was slightly above 43 EJ globally (around 18% of global electricity demand). Residential buildings
9 consumed 70% (90 EJ) of the global final energy demand from buildings. Over the period 1990-2019,
10 global CO2 emissions from buildings increased by 50%, global final energy demand from buildings
11 grew by 38% and global final electricity demand increased by 161%. {9.3}
12 In most regions, historical improvements in efficiency have been approximately matched by
13 growth in floor area per capita (high confidence). At the global level, building specific drivers of
14 GHG emissions include: (i) population growth, especially in developing countries; (ii) increasing floor
15 area per capita, driven by the increasing size of dwellings while the size of households kept decreasing,
16 especially in developed countries; (iii) the inefficiency of newly constructed buildings, especially in
17 developing countries, and the low renovation rates and low ambition level in developed countries when
18 existing buildings are renovated; iv) the increase in use, number and size of appliances and equipment,
19 especially Information and Communication Technologies (ICT) and cooling, driven by income; and,
20 (v) the continued reliance on carbon intensive electricity and heat. These factors taken together are
21 projected to continue driving increased GHG emissions in the building sector in the future. {9.3, 9.6,
22 9.9}
23 Building sector GHG emissions were assessed using the Sufficiency, Efficiency, Renewable (SER)
24 framework. Sufficiency measures tackle the causes of GHG emissions by limiting the demand for
25 energy and materials over the lifecycle of buildings and appliances (high confidence). In Chapter
26 9 of this report, sufficiency differs from efficiency. Sufficiency is about long-term actions driven by non-
27 technological solutions, which consume less energy in absolute terms. Efficiency, in contrast is about
28 continuous short-term marginal technological improvements. Use of the SER framework reduces the
29 cost of constructing and using buildings without reducing occupant’s well-being and comfort. {9.1, 9.4,
30 9.5, 9.9}
31 Sufficiency interventions do not consume energy during the use phase of buildings and do not
32 require maintenance nor replacement over the lifetime of buildings. Density, compacity,
33 bioclimatic design to optimise the use of nature-based solutions, multi-functionality of space through
34 shared space and to allow for adjusting the size of buildings to the evolving needs of households,
35 circular use of materials and repurposing unused existing buildings to avoid using virgin materials,
36 optimisation of the use of buildings through lifestyle changes, use of the thermal mass of buildings to
37 reduce thermal needs, moving from ownership to usership of appliances are among the sufficiency
38 interventions implemented in leading municipalities (high confidence). At a global level, up to 17% of
39 the mitigation potential in the buildings sector could be captured by 2050 through sufficiency
40 interventions (medium confidence). (Figure TS. 15) {9.2, 9.3, 9.4, 9.5, 9.9}.
41 The potential associated with sufficiency measures, as well as the replacement of appliances,
42 equipment and lights by efficient ones, is below zero cost (high confidence). The construction of
43 high-performance buildings is expected to become a business-as-usual technology by 2050 with costs
44 below USD20 tCO2-1 in developed countries and below USD100 tCO2-1 in developing countries
45 (medium confidence). For existing buildings, there have been many examples of deep retrofits where
46 additional costs per CO2 abated are not significantly higher than those of shallow retrofits. However,
47 for the whole building stock they tend to be in cost intervals of USD-200 tCO2-1 and >USD200 tCO2-1
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1 (medium confidence). Literature emphasizes the critical role of the 2020-2030 decade in accelerating
2 the learning of know-how and skills to reduce the costs and remove feasibility constraints for achieving
3 high efficiency buildings at scale and set the sector in the pathway to realize its full potential (high
4 confidence). {9.3, 9.6, 9.9}.
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1
2
3 Panel a: global
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1
2 Panel b: regional
3 Figure TS.15: Decompositions of changes in historical residential energy emissions 1990-2019, changes in emissions projected by baseline scenarios for 2020-2050,
4 and differences between scenarios in 2050 using scenarios from three models: IEA, IMAGE, and RECC.
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1 Figure TS.15 legend: RECC-LED data include only space heating and cooling and water heating in residential
2 buildings (a) Global resolution, and (b) for nine world regions. Emissions are decomposed using the equation
m² EJ MtCO2
3 CO2 Pop × × × = Pop × Sufficiency × Efficiency × Renenewable, which shows changes in
Pop m² EJ
4 driver variables of population, sufficiency (floor area per capita), efficiency (final energy per floor area), and
5 renewables (GHG emissions per final energy). ‘Renewables’ is a summary term describing changes in GHG
6 intensity of energy supply. Emission projections to 2050, and differences between scenarios in 2050,
7 demonstrate mitigation potentials from the dimensions of the SER framework realised in each model scenario.
8 In most regions, historical improvements in efficiency have been approximately matched by growth in floor area
9 per capita. Implementing sufficiency measures that limit growth in floor area per capita, particularly in
10 developed regions, reduces the dependence of climate mitigation on technological solutions. {Figure 9.5, Box
11 9.2}
12 The development, since AR5, of integrated approaches to the construction and retrofit of
13 buildings has led to increasing the number of zero energy or zero carbon buildings in almost all
14 climate zones. The complementarity and interdependency of measures leads to cost reductions, while
15 optimising the mitigation potential achieved and avoiding the lock-in-effect (medium confidence). {9.6,
16 9.9}
17 The decarbonisation of buildings is constrained by multiple barriers and obstacles as well as
18 limited finance flows (high confidence). The lack of institutional capacity, especially in developing
19 countries, and appropriate governance structures slow down the decarbonisation of the global
20 building stock (medium confidence). The building sector is highly heterogenous with many different
21 building types, sizes, and operational uses. The sub-segment representing rented property faces
22 principal/agent problems where the tenant benefits from the decarbonisation’s investment made by the
23 landlord. The organisational context and the governance structure could trigger or hinder the
24 decarbonisation of buildings. Global investment in the decarbonisation of buildings was estimated at
25 USD164 billion in 2020. However, this is not enough by far to close the investment gap (high
26 confidence). {9.9}
27 Policy packages could grasp the full mitigation potential of the global building stock. Building
28 energy codes represent the main regulatory instrument to reduce emissions from both new and
29 existing buildings (high confidence). The most advanced building energy codes include requirements
30 on each of the three pillars of the SER framework in the use and construction phase of buildings.
31 Building energy codes have proven to be effective if compulsory and combined with other regulatory
32 instruments such as minimum energy performance standard for appliances and equipment, if the
33 performance level is set at the level of the best available technologies in the market (high confidence).
34 Market-based instruments such as carbon taxes with recycling of the revenues and personal or building
35 carbon allowances could also contribute to fostering the decarbonisation of the building sector (medium
36 confidence). {9.9}
37 Adapting buildings to future climate while ensuring well-being for all requires action. Expected
38 heatwaves will inevitably increase cooling needs to limit the health impacts of climate change
39 (medium confidence). Global warming will impact cooling and heating needs but also the performance,
40 durability and safety of buildings, especially historical and coastal ones, through changes in
41 temperature, humidity, atmospheric concentrations of CO2 and chloride, and sea level rise. Adaptation
42 measures to cope with climate change may increase the demand for energy and materials leading to an
43 increase in GHG emissions if not mitigated. Sufficiency measures which anticipate climate change, and
44 include natural ventilation, white walls, and nature-based solutions (e.g. green roofs) will decrease the
45 demand for cooling. Shared cooled spaces with highly efficient cooling solutions are among the
46 mitigation strategies which can limit the effect of the expected heatwaves on people’s health. {9.7, 9.8}
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1 Well-designed and effectively implemented mitigation actions in the buildings sector have
2 significant potential to help achieve the SDGs (high confidence). As shown in Figure TS.16, the
3 impacts of mitigation actions in the building sector go far beyond the goal of climate action (SDG13)
4 and contribute to meeting fifteen other SDGs. Mitigation actions in the building sector bring health
5 gains through improved indoor air quality and thermal comfort, and have positive significant macro-
6 and micro-economic effects, such as increased productivity of labour, job creation, reduced poverty,
7 especially energy poverty, and improved energy security (high confidence). (Figure TS.29) {9.8}
8
9
10 Figure TS.16. Contribution of building sector mitigation policies to meeting sustainable development
11 goals. {Figure 9.18}
12 The COVID-19 pandemic emphasised the importance of buildings for human well-being and
13 highlighted the inequalities in access for all to suitable, healthy buildings, which provide natural
14 daylight and clean air to their occupants (medium confidence). The new WHO health
15 recommendations emphasised indoor air quality, preventive maintenance of centralised mechanical
16 heating, ventilation, and cooling systems. There are opportunities for repurposing existing non-
17 residential buildings, no longer in use due to the expected spread of teleworking triggered by the health
18 crisis and enabled by digitalisation. (TS BOX.14) {9.1}
19
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1 TS. 5.5 Industry
2 The industry chapter focuses on new developments since AR5 and emphasises the role of the energy-
3 intensive and emissions-intensive basic materials industries in strategies for reaching net zero
4 emissions. The Paris Agreement, the SDGs and the COVID-19 pandemic provide a new context for the
5 evolution of industry and mitigation of industry greenhouse gas (GHG) emissions (high confidence).
6 {11.1.1}
7 Net zero CO2 industrial sector emissions are possible but challenging (high confidence). Energy
8 efficiency will continue to be important. Reduced materials demand, material efficiency, and circular
9 economy solutions can reduce the need for primary production. Primary production options include
10 switching to new processes that use low to zero GHG energy carriers and feedstocks (e.g., electricity,
11 hydrogen, biofuels, and carbon dioxide capture and utilisation (CCU) to provide carbon feedstocks).
12 Carbon capture and storage (CCS) will be required to mitigate remaining CO2 emissions {11.3}. These
13 options require substantial scaling up of electricity, hydrogen, recycling, CO2, and other infrastructure,
14 as well as phase-out or conversion of existing industrial plants. While improvements in the GHG
15 intensities of major basic materials have nearly stagnated over the last 30 years, analysis of historical
16 technology shifts and newly available technologies indicate these intensities can be significantly
17 reduced by mid-century. {11.2, 11.3, 11.4}
18 Industry sector emissions have been growing faster since 2000 than emissions in any other sector,
19 driven by increased basic materials extraction and production (high confidence). GHG emissions
20 attributed to the industrial sector originate from fuel combustion, process emissions, product use and
21 waste, which jointly accounted for 14.1 GtCO2-eq or 24% of all direct anthropogenic emissions in 2019,
22 second behind the energy supply sector. Industry is a leading GHG emitter - 20 GtCO2-eq or 34% of
23 global emissions in 2019 - if indirect emissions from power and heat generation are included. The share
24 of emissions originating from direct fuel combustion is decreasing and was 7 GtCO2-eq, 50% of direct
25 industrial emissions in 2019. {11.2.2}
26 Global material intensity – the in-use stock of manufactured capital in tonnes per unit of GDP–
27 is increasing (high confidence). In-use stock of manufactured capital per capita has been growing
28 faster than GDP per capita since 2000. Total global in-use stock of manufactured capital grew by 3.4%
29 yr-1 in 2000–2019. At the same time, per capita material stocks in several developed countries have
30 stopped growing, showing a decoupling from GDP per capita. {11.2.1, 11.3.1}
31 The demand for plastic has been growing most strongly since 1970 (high confidence). The current
32 >99% reliance on fossil feedstock, very low recycling, and high emissions from petrochemical
33 processes is a challenge for reaching net zero emissions. At the same time, plastics are important for
34 reducing emissions elsewhere, for example, light-weighting vehicles. There are as yet no shared visions
35 for fossil-free plastics, but several possibilities. {11.4.1.3}
36 Scenario analyses show that significant reductions in global GHG emissions and even close to net
37 zero emissions from GHG intensive industry (e.g., steel, plastics, ammonia, and cement) can be
38 achieved by 2050 by deploying multiple available and emerging options (medium confidence).
39 Significant reductions in industry emissions require a reorientation from the historic focus on important
40 but incremental improvements (e.g., energy efficiency) to transformational changes in energy and
41 feedstock sourcing, materials efficiency, and more circular material flows. {11.3, 11.4}
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1
2
3
Figure TS.17 Page-i: Potentials and costs for zero-carbon mitigation options for industry and basic materials
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1
Figure TS.17 Page-ii: Potentials and costs for zero-carbon mitigation options for industry and basic materials
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1
2
3 Figure TS.17 page-iii : Potentials and costs for zero-carbon mitigation options for industry and basic materials
4 Figure TS.17 legend: Key shown on Figure TS.17 page-i also applies to TS.17 pages ii & iii. CIEl –carbon intensity of electricity for indirect emissions; EE – energy
5 efficiency; ME – material efficiency; Circularity - material flows (clinker substituted by coal fly ash, blast furnace slag or other by-products and waste, steel scrap, plastic
6 recycling, etc.); FeedCI – feedstock carbon intensity (hydrogen, biomass, novel cement, natural clinker substitutes); FSW+El – fuel switch and processes electrification with
7 low carbon electricity. Ranges for mitigation options are shown based on bottom-up studies for grouped technologies packages, not for single technologies. In circles
8 contribution to mitigation from technologies based on their readiness are shown for 2050 (2040) and 2070. Direct emissions include fuel combustion and process emissions.
9 Indirect emissions include emissions attributed to consumed electricity and purchased heat. For basic chemicals only methanol, ammonia and high-value chemicals are
10 considered. Total for industry does not include emissions from waste. Negative mitigation costs for some options like Circularity are not reflected. {Figure 11.13}
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1 Key mitigation options such as materials efficiency, circular material flows and emerging primary
2 processes, are not well represented in climate change scenario modelling and integrated
3 assessment models, albeit with some progress in recent years (high confidence). The character of
4 these interventions (e.g., appearing in many forms across complex value chains, making cost estimates
5 difficult) combined with the limited data on new fossil free primary processes help explain why they
6 are less represented in models than, for example, CCS. As a result, overall mitigation costs and the need
7 for CCS may be overestimated. {11.4.2.1}
8 Electrification is emerging as a key mitigation option for industry (high confidence). Using
9 electricity directly, or indirectly via hydrogen from electrolysis for high temperature and chemical
10 feedstock requirements, offers many options to reduce emissions. It also can provide substantial grid
11 balancing services, for example through electrolysis and storage of hydrogen for chemical process use
12 or demand response. (Box TS.9) {11.3.5}
13 Carbon is a key building block in organic chemicals, fuels and materials and will remain
14 important (high confidence). In order to reach net zero CO2 emissions for the carbon needed in society
15 (e.g., plastics, wood, aviation fuels, solvents, etc.), it is important to close the use loops for carbon and
16 carbon dioxide through increased circularity with mechanical and chemical recycling, more efficient
17 use of biomass feedstock with addition of low GHG hydrogen to increase product yields (e.g., for
18 biomethane and methanol), and potentially direct air capture of CO2 as a new carbon source. {11.3,
19 11.4.1}
20 Production costs for very low to zero emissions basic materials may be high but the cost for final
21 consumers and the general economy will be low (medium confidence). Costs and emissions
22 reductions potential in industry, and especially heavy industry, are highly contingent on innovation,
23 commercialisation, and market uptake policies. Technologies exist to take all industry sectors to very
24 low or zero emissions, but require 5–15 years of intensive innovation, commercialisation, and policy to
25 ensure uptake. Mitigation costs are in the rough range of USD50–150 tCO2-eq-1, with wide variation
26 within and outside this band. This affects competitiveness and requires supporting policy. Although
27 production cost increases can be significant, they translate to very small increases in the costs for final
28 products, typically less than a few percent depending on product, assumptions, and system boundaries.
29 (Figure TS.17) {11.4.1.5}
30 Several technological options exist for very low to zero emissions steel, but their uptake will
31 require integrated material efficiency, recycling, and production decarbonisation policies (high
32 confidence). Material efficiency can potentially reduce steel demand by up to 40% based on design for
33 less steel use, long life, reuse, constructability, and low contamination recycling. Secondary production
34 through high quality recycling must be maximised. Production decarbonisation will also be required,
35 starting with the retrofitting of existing facilities for partial fuel switching (e.g., to biomass or hydrogen),
36 CCU and CCS, followed by very low and zero emissions production based on high-capture CCS or
37 direct hydrogen, or electrolytic iron ore reduction followed by an electric arc furnace. {11.3.2, 11.4.1.1}
38 Several current and emerging options can significantly reduce cement and concrete emissions.
39 Producer, user, and regulator education, as well as innovation and commercialisation policy are
40 needed (medium confidence). Cement and concrete are currently overused because they are
41 inexpensive, durable, and ubiquitous, and consumption decisions typically do not give weight to their
42 production emissions. Basic material efficiency efforts to use only well-made concrete thoughtfully and
43 only where needed (e.g., using right-sized, prefabricated components) could reduce emissions by 24–
44 50% through lower demand for clinker. Cementitious material substitution with various materials (e.g.,
45 ground limestone and calcined clays) can reduce process calcination emissions by up to 50% and
46 occasionally much more. Until a very low GHG emissions alternative binder to Portland cement is
47 commercialised – which is not anticipated in the near to medium term – CCS will be essential for
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1 eliminating the limestone calcination process emissions for making clinker, which currently represent
2 60% of GHG emissions in best available technology plants. {11.3.2, 11.3.6, 11.4.1.2}
3 While several technological options exist for decarbonizing the main industrial feedstock
4 chemicals and their derivatives, the costs vary widely (high confidence). Fossil fuel-based
5 feedstocks are inexpensive and still without carbon pricing, and their biomass- and electricity-based
6 replacements are expected to be more expensive. The chemical industry consumes large amounts of
7 hydrogen, ammonia, methanol, carbon monoxide, ethylene, propylene, benzene, toluene, and mixed
8 xylenes & aromatics from fossil feedstock, and from these basic chemicals produces tens of thousands
9 of derivative end-use chemicals. Hydrogen, biogenic or air-capture carbon, and collected plastic waste
10 for the primary feedstocks can greatly reduce total emissions. Biogenic carbon feedstock is expected to
11 be limited due to competing land-uses. {11.4.1}
12 Light industry and manufacturing can be largely decarbonized through switching to low GHG
13 fuels (e.g., biofuels and hydrogen) and electricity (e.g., for electrothermal heating and heat
14 pumps) (high confidence). Most of these technologies are already mature, for example for low
15 temperature heat, but a major challenge is the current low cost of fossil CH4 and coal relative to low and
16 zero GHG electricity, hydrogen, and biofuels. {11.4.1}
17 The pulp and paper industry has significant biogenic carbon emissions but relatively small fossil
18 carbon emissions. Pulp mills have access to biomass residues and by-products and in paper mills
19 the use of process heat at low to medium temperatures allows for electrification (high confidence).
20 Competition for feedstock will increase if wood substitutes for building materials and petrochemicals
21 feedstock. The pulp and paper industry can also be a source of biogenic carbon dioxide, carbon for
22 organic chemicals feedstock, and for CDR using CCS. {11.4.1}
23 The geographical distribution of renewable resources has implications for industry (medium
24 confidence). The potential for zero emission electricity and low-cost hydrogen from electrolysis
25 powered by solar and wind, or hydrogen from other very low emission sources, may reshape where
26 currently energy and emissions intensive basic materials production is located, how value chains are
27 organized, trade patterns, and what gets transported in international shipping. Regions with bountiful
28 solar and wind resources, or low fugitive CH4 co-located with CCS geology, may become exporters of
29 hydrogen or hydrogen carriers such as methanol and ammonia, or home to the production of iron and
30 steel, organic platform chemicals, and other energy intensive basic materials. {11.2, 11.4, Box 11.1}
31 The level of policy maturity and experience varies widely across the mitigation options (high
32 confidence). Energy efficiency is a well-established policy field with decades of experience from
33 voluntary and negotiated agreements, regulations, energy auditing and demand side-management
34 (DSM) programs. In contrast, materials demand management and efficiency are not well understood
35 and addressed from a policy perspective. Barriers to recycling that policy could address are often
36 specific to the different material loops (e.g., copper contamination for steel and lack of technologies or
37 poor economics for plastics) or waste management systems. For electrification and fuel switching the
38 focus has so far been mainly on innovation and developing technical supply-side solutions rather than
39 creating market demand. {11.5.2, 11.6}
40 Industry has so far largely been sheltered from the impacts of climate policy and carbon pricing
41 due to concerns about carbon leakage18 and reducing competitiveness (high confidence). New
42 approaches to industrial development policy are emerging for a transition to net zero GHG emissions.
43 The transition requires a clear direction towards net zero, technology development, market demand for
44 low-carbon materials and products, governance capacity and learning, socially inclusive phase-out
45 plans, as well as international coordination of climate and trade policies (see also TS 6.5). It requires
FOOTNOTE 18 See section TS 5.9
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1 comprehensive and sequential industrial policy strategies leading to immediate action as well as
2 preparedness for future decarbonisation, governance at different levels (from international to local) and
3 integration with other policy domains. {11.6}
4
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1 TS. 5.6 Agriculture, forestry and other land uses, and food systems
2 TS. 5.6.1 AFOLU
3 The Agriculture, Forestry and Other Land Uses (AFOLU)19 sector encompasses managed
4 ecosystems and offers significant mitigation opportunities while providing food, wood and other
5 renewable resources as well as biodiversity conservation, provided the sector adapts to climate
6 change. Land-based mitigation measures can reduce GHG emissions within the AFOLU sector, deliver
7 CDR and provide biomass thereby enabling emission reductions in other sectors.20 The rapid
8 deployment of AFOLU measures features in all pathways that l limit global warming to 1.5°C. Where
9 carefully and appropriately implemented, AFOLU mitigation measures are positioned to deliver
10 substantial co-benefits and help address many of the wider challenges associated with land
11 management. If AFOLU measures are deployed badly then, when taken together with the increasing
12 need to produce sufficient food, feed, fuel and wood, they may exacerbate trade-offs with the
13 conservation of habitats, adaptation, biodiversity and other services. At the same time the capacity of
14 the land to support these functions may be threatened by climate change. (high confidence) {WG I
15 Figure SPM7; WG II, 7.1, 7.6}
16 The AFOLU sector, on average, accounted for 13-21% of global total anthropogenic GHG
17 emissions in the period 2010-2019. At the same time managed and natural terrestrial ecosystems
18 were a carbon sink, absorbing around one third of anthropogenic CO2 emissions (medium
19 confidence). Estimated anthropogenic net CO2 emissions from AFOLU (based on bookkeeping models)
20 result in a net source of +5.9 ± 4.1 GtCO2 yr-1 between 2010 and 2019 with an unclear trend. Based on
21 FAOSTAT or national GHG inventories, the net CO2 emissions from AFOLU were 0.0 to +0.8 GtCO2
22 yr-1 over the same period. There is a discrepancy in the reported CO2 AFOLU emissions magnitude
23 because alternative methodological approaches that incorporate different assumptions are used {7.2.2}.
24 If the responses of all managed and natural land to both anthropogenic environmental change and
25 natural climate variability, estimated to be a gross sink of -12.5 ± 3.2 GtCO2 yr-1 for the period 2010–
26 2019, are added to land-use emissions, then land overall constituted a net sink of -6.6 ± 5.2 GtCO2 yr-1
27 in terms of CO2 emissions (medium confidence). (Table TS.4) {7.2, Table 7.1}
28 Land use change drives net AFOLU CO2 emission fluxes. The rate of deforestation, which
29 accounts for 45% of total AFOLU emissions, has generally declined, while global tree cover and
30 global forest growing stock levels are likely increasing (medium confidence). There are substantial
31 regional differences, with losses of carbon generally observed in tropical regions and gains in temperate
32 and boreal regions. Agricultural CH4 and N2O emissions are estimated to average 157 ± 47.1 MtCH4
33 yr-1 and 6.6 ± 4.0 MtN2O yr-1 or 4.2 ± 1.3 and 1.8 ± 1.1 GtCO2-eq yr-1 (using IPCC AR6 GWP100
34 values for CH4 and N2O) respectively between 2010 and 2019 {7.2.1, 7.2.3}. AFOLU CH4 emissions
35 continue to increase, the main source of which is enteric fermentation from ruminant animals. Similarly,
36 AFOLU N2O emissions are increasing, dominated by agriculture, notably from manure application,
FOOTNOTE 19 AFOLU is a sector in the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse
Gas Inventories. AFOLU anthropogenic greenhouse gas emissions and removals by sinks reported by
governments under the UNFCCC are defined as all those occurring on ‘managed land’. Managed land is land
where human interventions and practices have been applied to perform production, ecological or social functions.
FOOTNOTE 20 For example: in the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas
Inventories, CO2 emissions from biomass used for energy are reported in the AFOLU sector, calculated as an
implicit component of carbon stock changes. In the energy sector, CO2 emissions from biomass combustion for
energy are recorded as an information item that is not included in the sectoral total emissions for the that sector.
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1 nitrogen deposition, and nitrogen fertiliser use (high confidence). In addition to being a net carbon sink
2 and source of GHG emissions, land plays an important role in climate through albedo effects,
3 evapotranspiration, and aerosol loading through emissions of volatile organic compounds (VOCs). The
4 combined role of CH4, N2O and aerosols in total climate forcing, however, is unclear and varies strongly
5 with bioclimatic region and management practice. {2.4.2.5, 7.2, 7.3}
6 Table TS.4 Net anthropogenic emissions (annual averages for 2010–2019a) from Agriculture, Forestry
7 and Other Land Use (AFOLU)
8
9 For context, the net flux due to the natural response of land to climate and environmental change is also
10 shown for CO2 in column E. Positive values represent emissions, negative values represent removals.
11 Due to different approaches to estimate anthropogenic fluxes, AFOLU CO2 estimates in the table
12 below are not directly comparable to LULUCF in National Greenhouse Gas Inventories (NGHGIs).
13
Anthropogenic Natural Natural +
Response Anthropogenic
Gas Units AFOLU Net Non- Total net AFOLU as Natural land Net-land
anthropogenic AFOLU anthropogenic a % of total sinks including atmosphere CO2
emissions anthropog emissions net natural response flux (i.e.
enic GHG (AFOLU + anthropoge of land to anthropogenic
emissions non-AFOLU) nic anthropogenic AFOLU +
by gas emissions environmental natural fluxes
by gas change and across entire land
climate surface
variability
A B C = A+B D = (A/C) E F=A+E
*100
CO2 GtCO2-eq yr-1 5.9 ± 4.1 36.2 ± 2.9 42.0 ± 29.0 14% -12.5 ± 3.2 -6.6 ± 4.6
(bookkeeping models
only)
0 to 0.8
(NGHGI/
FAOSTAT data)
MtCH4 yr-1 157.0 ± 47.1 207.5 ± 364.4 ± 109.3
CH4 62.2
GtCO2-eq yr-1 4.2 ± 1.3 5.9 ± 1.8 10.2 ± 3.0 41%
MtN2O yr-1 6.6 ± 4.0 2.8 ± 1.7 9.4 ± 5.6
N2O GtCO2-eq yr-1 1.8 ± 1.1 0.8 ± 0.5 2.6 ± 1.5 69%
Total GtCO2-eq yr-1 11.9 ± 4.4 44 ± 3.4 55.9 ± 6.1 21%
(CO2 component
considers
bookkeeping models
only)
14
15 a Estimates are given for 2019 as this is the latest date when data are available for all gases, consistent with Chapter 2, this
16 report. Positive fluxes are emission from land to the atmosphere. Negative fluxes are removals.
17 {Table 7.1}
18 The AFOLU sector offers significant near-term mitigation potential at relatively low cost and can
19 provide 20-30% of the 2050 emissions reduction described in scenarios that likely limit warming
20 to 2°C or lower (high evidence, medium agreement). The AFOLU sector can provide 20–30%
21 (interquartile range) of the global mitigation needed for a 1.5 oC or 2oC pathway towards 2050, though
22 there are highly variable mitigation strategies for how AFOLU potential can be deployed for achieving
23 climate targets {Illustrative Mitigation Pathways in 7.5}. The estimated economic (< USD100 tCO2-eq-
24 1
) AFOLU sector mitigation potential is 8 to 14 GtCO2-eq yr-1 between 2020-2050, with the bottom end
25 of this range representing the mean from IAMs and the upper end representing the mean estimate from
26 global sectoral studies. The economic potential is about half of the technical potential from AFOLU,
27 and about 30-50% could be achieved under USD20 tCO2-eq-1 {7.4}. The implementation of robust
28 measurement, reporting and verification processes is paramount to improving the transparency of
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1 changes in land carbon stocks and this can help prevent misleading assumptions or claims on mitigation.
2 {7.1, 7.4, 7.5}
3 Between 2020 and 2050, mitigation measures in forests and other natural ecosystems provide the
4 largest share of the AFOLU mitigation potential (up to USD100 tCO2-eq-1), followed by
5 agriculture and demand-side measures (high confidence). In the global sectoral studies, the
6 protection, improved management, and restoration of forests, peatlands, coastal wetlands, savannas and
7 grasslands have the potential to reduce emissions and/or sequester 7.3 mean (3.9–13.1 range) GtCO2-
8 eq yr-1. Agriculture provides the second largest share of the mitigation potential, with 4.1 (1.7–6.7)
9 GtCO2-eq yr-1 (up to USD100 tCO2-eq-1) from cropland and grassland soil carbon management,
10 agroforestry, use of biochar, improved rice cultivation, and livestock and nutrient management.
11 Demand-side measures including shifting to sustainable healthy diets, reducing food waste, building
12 with wood, biochemicals, and bio-textiles, have a mitigation potential of 2.2 (1.1–3.6) GtCO2-eq yr-1.
13 Most mitigation options are available and ready to deploy. Emissions reductions can be achieved
14 relatively quickly, whereas CDR needs upfront investment. Sustainable intensification in agriculture,
15 shifting diets, and reducing food waste could enhance efficiencies and reduce agricultural land needs,
16 and are therefore critical for enabling supply-side measures such as reforestation, restoration, as well as
17 decreasing CH4 and N2O emissions from agricultural production. In addition, emerging technologies
18 (e.g., vaccines or CH4 inhibitors) have the potential to substantially increase the CH4 mitigation
19 potential beyond current estimates. AFOLU mitigation is not only relevant in countries with large land
20 areas. Many smaller countries and regions, particularly with wetlands, have disproportionately high
21 levels of AFOLU mitigation potential density. {7.4, 7.5}
22 The economic and political feasibility of implementing AFOLU mitigation measures is hampered
23 by persistent barriers. Assisting countries to overcome barriers will help to achieve significant
24 short-term mitigation (medium confidence). Finance forms a critical barrier to achieving these gains
25 as currently mitigation efforts rely principally on government sources and funding mechanisms which
26 do not provide sufficient resources to enable the economic potential to be realised. Differences in
27 cultural values, governance, accountability and institutional capacity are also important barriers.
28 Climate change itself could reduce the mitigation potential from the AFOLU sector, although an
29 increase in the capacity of natural sinks could occur despite changes in climate (medium confidence)
30 {WG I Figure SPM7 and Sections 7.4 and 7.6}. The continued loss of biodiversity makes ecosystems
31 less resilient to climate change extremes and this may further jeopardise the achievement of the AFOLU
32 mitigation potentials indicated in this chapter (high confidence). (Box TS.15) {7.6}
33 The provision of biomass for bioenergy (with/without BECCS) and other biobased products
34 represents an important share of the total mitigation potential associated with the AFOLU sector,
35 though these mitigation effects accrue to other sectors (high confidence). Recent estimates of the
36 technical bioenergy potential, when constrained by food security and environmental considerations, are
37 within the ranges 5–50 and 50–250 EJ yr-1 by 2050 for residues and dedicated biomass production
38 systems, respectively.21 (TS 5.7) {7.4, 12.3}
FOOTNOTE 21 These potentials do not include avoided emissions resulting from bioenergy use associated with
BECCS, which depends on energy substitution patterns, conversion efficiencies, and supply chain emissions for
both the BECCS and substituted energy systems. Estimates of substitution effects of bioenergy indicate that this
additional mitigation would be of the same magnitude as provided through CDR using BECCS. Biobased products
with long service life, e.g., construction timber, can also provide mitigation through substitution of steel, concrete,
and other products, and through carbon storage in the biobased product pool. See section TS 5.7 for the CDR
potential of BECCS. {7.4, 12.3}
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1 Bioenergy is the most land-intensive energy option, but total land occupation of other renewable
2 energy options can also become significant in high deployment scenarios. While not as closely
3 connected to the AFOLU sector as bioenergy, other renewable energy options can influence
4 AFOLU activities in both synergistic and detrimental ways (high confidence). The character of land
5 occupation, and associated impacts, vary considerably among mitigation options and also for the same
6 option depending on geographic location, scale, system design and deployment strategy. Land
7 occupation can be large uniform areas, e.g., reservoir hydropower dams and tree plantations, and more
8 distributed occupation that is integrated with other land uses, e.g., wind turbines and agroforestry in
9 agriculture landscapes. Deployment can be partly decoupled from additional land use, e.g., use of
10 organic waste and residues and integration of solar PV into buildings and other infrastructure (high
11 confidence). Wind and solar power can coexist with agriculture in beneficial ways (medium confidence).
12 Indirect land occupation includes new agriculture areas following displacement of food production with
13 bioenergy plantations and expansion of mining activities providing minerals required for manufacture
14 of EV batteries, PV, and wind power. {7.4, 12.5}
15 The deployment of land-based mitigation measures can provide co-benefits, but there are also
16 risks and trade-offs from inappropriate land management (high confidence). Such risks can best
17 be managed if AFOLU mitigation is pursued in response to the needs and perspectives of multiple
18 stakeholders to achieve outcomes that maximise synergies while limiting trade-offs (medium
19 confidence). The results of implementing AFOLU measures are often variable and highly context
20 specific. Depending on local conditions (e.g., ecosystem, climate, food system, land ownership) and
21 management strategies (e.g., scale, method), mitigation measures can positively or negatively affect
22 biodiversity, ecosystem functioning, air quality, water availability and quality, soil productivity, rights
23 infringements, food security, and human well-being. The agriculture and forestry sectors can devise
24 management approaches that enable biomass production and use for energy in conjunction with the
25 production of food and timber, thereby reducing the conversion pressure on natural ecosystems (medium
26 confidence). Mitigation measures addressing GHGs may also affect other climate forcers such as albedo
27 and evapotranspiration. Integrated responses that contribute to mitigation, adaptation, and other land
28 challenges will have greater likelihood of being successful (high confidence); measures which provide
29 additional benefits to biodiversity and human well-being are sometimes described as ‘Nature-based
30 Solutions’. {7.1, 7.4, 7.6, 12.4, 12.5}
31 AFOLU mitigation measures have been well understood for decades but deployment remains
32 slow, and emissions trends indicate unsatisfactory progress despite beneficial contributions to
33 global emissions reduction from forest-related options (high confidence). Globally, the AFOLU
34 sector has so far contributed modestly to net mitigation, as past policies have delivered about 0.65
35 GtCO2 yr-1 of mitigation during 2010–2019 or 1.4% of global gross emissions. The majority (>80%) of
36 emission reduction resulted from forestry measures. Although the mitigation potential of AFOLU
37 measures is large from a biophysical and ecological perspective, its feasibility is hampered by lack of
38 institutional support, uncertainty over long-term additionality and trade-offs, weak governance,
39 fragmented land ownership, and uncertain permanence effects. Despite these impediments to change,
40 AFOLU mitigation options are demonstrably effective and with appropriate support can enable rapid
41 emission reductions in most countries. {7.4, 7.6}
42 Concerted, rapid and sustained effort by all stakeholders, from policy makers and investors to
43 land-owners and managers is a pre-requisite for achieving high levels of mitigation in the AFOLU
44 sector (high confidence). To date USD0.7 billion yr-1 is estimated to have been spent on AFOLU
45 mitigation. This is well short of the more than USD400 billion yr-1 that is estimated to be necessary to
46 deliver the up to 30% of global mitigation effort envisaged in deep mitigation scenarios (medium
47 confidence). This estimate of the global funding requirement is smaller than current subsidies provided
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1 to agriculture and forestry. A gradual redirection of existing agriculture and forestry subsidies would
2 greatly advance mitigation. Effective policy interventions and national (investment) plans as part of
3 NDCs, specific to local circumstances and needs, are urgently needed to accelerate the deployment of
4 AFOLU mitigation options. These interventions are effective when they include funding schemes and
5 long-term consistent support for implementation with governments taking the initiative together with
6 private funders and non-state actors. {7.6}
7 Realising the mitigation potential of the AFOLU sector depends strongly on policies that directly
8 address emissions and drive the deployment of land-based mitigation options, consistent with
9 carbon prices in deep mitigation scenarios (high confidence). Examples of successful policies and
10 measures include establishing and respecting tenure rights and community forestry, improved
11 agricultural management and sustainable intensification, biodiversity conservation, payments for
12 ecosystem services, improved forest management and wood chain usage, bioenergy, voluntary supply
13 chain management efforts, consumer behaviour campaigns, private funding and joint regulatory efforts
14 to avoid e.g., leakage. The efficacy of different policies, however, will depend on numerous region-
15 specific factors. In addition to funding, these factors include governance, institutions, long-term
16 consistent execution of measures, and the specific policy setting. While the governance of land-based
17 mitigation can draw on lessons from previous experience with regulating biofuels and forest carbon
18 integrating these insights requires governance that goes beyond project-level approaches emphasising
19 integrated land use planning and management within the frame of the sustainable development goals.
20 {7.4, Box 7.2, 7.6}
21 Addressing the many knowledge gaps in the development and testing of AFOLU mitigation
22 options can rapidly advance the likelihood of achieving sustained mitigation (high confidence).
23 Research priorities include improved quantification of anthropogenic and natural GHG fluxes and
24 emissions modelling, better understanding of the impacts of climate change on the mitigation potential,
25 permanence and additionality of estimated mitigation actions, and improved (real time and cheap)
26 measurement, reporting and verification. There is a need to include a greater suite of mitigation
27 measures in IAMs, informed by more realistic assessments that take into account local circumstances
28 and socio-economic factors and cross-sector synergies and trade-offs. Finally, there is a critical need
29 for more targeted research to develop appropriate country-level, locally specific, policy and land
30 management response options. These options could support more specific NDCs with AFOLU
31 measures that enable mitigation while also contributing to biodiversity conservation, ecosystem
32 functioning, livelihoods for millions of farmers and foresters, and many other SDGs. {7.7, Figure 17.1}
33 TS. 5.6.2 Food systems
34 Realising the full mitigation potential from the food system requires change at all stages from
35 producer to consumer and waste management, which can be facilitated through integrated policy
36 packages (high confidence). 23-42% of global GHG emissions are associated with food systems, while
37 there is still wide-spread food insecurity and malnutrition. Absolute GHG emissions from food systems
38 increased from 14 to 17 GtCO2-eq yr-1 in the period 1990-2018. Both supply and demand side measures
39 are important to reduce the GHG intensity of food systems. Integrated food policy packages based on a
40 combination of market-based, administrative, informative, and behavioural policies can reduce cost
41 compared to uncoordinated interventions, address multiple sustainability goals, and increase acceptance
42 across stakeholders and civil society (limited evidence, medium agreement). Food systems governance
43 may be pioneered through local food policy initiatives complemented by national and international
44 initiatives, but governance on the national level tends to be fragmented, and thus have limited capacity
45 to address structural issues like inequities in access. (Figure TS.18, Table TS.5, Table TS.6) {7.2, 7.4,
46 12.4}
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1
2 Figure TS.18: Food system GHG emissions from the agriculture, Land Use, Land-Use Change & Forestry
3 (LULUCF), Waste, and energy & industry sectors. {Figure 12.5}
4
5 Diets high in plant protein and low in meat and dairy are associated with lower GHG emissions
6 (high confidence). Ruminant meat shows the highest GHG intensity. Beef from dairy systems has lower
7 emissions intensity than beef from beef herds (8-23 and 17-94 kgCO2-eq (100g protein)-1, respectively)
8 when some emissions are allocated to dairy products. The wide variation in emissions reflects
9 differences in production systems, which range from intensive feedlots with stock raised largely on
10 grains through to rangeland and transhumance production systems. Where appropriate, a shift to diets
11 with a higher share of plant protein, moderate intake of animal-source foods and reduced intake of
12 saturated fats could lead to substantial decreases in GHG emissions. Benefits would also include
13 reduced land occupation and nutrient losses to the surrounding environment, while at the same time
14 providing health benefits and reducing mortality from diet-related non-communicable diseases. (Figure
15 TS.19) {7.4.5, 12.4}
16 Emerging food technologies such as cellular fermentation, cultured meat, plant-based
17 alternatives to animal-based food products, and controlled environment agriculture, can bring
18 substantial reduction in direct GHG emissions from food production (limited evidence, high
19 agreement). These technologies have lower land, water, and nutrient footprints, and address concerns
20 over animal welfare. Realising the full mitigation potential depends on access to low-carbon energy as
21 some emerging technologies are relatively more energy intensive. This also holds for deployment of
22 cold chain and packaging technologies, which can help reduce food loss and waste, but increase energy
23 and materials use in the food system. (Table TS.5) {11.4.1.3, 12.4}
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1
2
3
4 Figure TS.19: Regional differences in health outcome, territorial per capita GHG emissions from national
5 food systems, and share of food system GHG emission from energy use
6 Figure TS.19 legend: GHG emissions are calculated according to the IPCC Tier 1 approach and are assigned to
7 the country where they occur, not necessarily where the food is consumed. Health outcome is expressed as
8 relative contribution of each of the following risk factors to their combined risk for deaths: Child and maternal
9 malnutrition (red), Dietary risks (yellow) or High body-mass index (blue). {Figure 12.7}
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1 Table TS.5 Food system mitigation opportunities
2
Food system mitigation options (I: incremental; T: Direct and indirect effect on GHG mitigation Co-benefits / Adverse effects b
transformative) (+/0/-) a
Food from (I) Dietary shift, in particular D+ ↓ GHG footprint A+ Animal welfare
agricultural, increased share of plant-based L+ Land sparing
aquaculture protein sources H+ Good nutritional properties, potentially ↓ risk from zoonotic
and fisheries diseases, pesticides and antibiotics
(I/T) Digital agriculture D+ ↑ logistics L+ Land sparing
R+ ↑ resource use efficiencies
(T) Gene technology D+ ↑ productivity or efficiency H+ ↑ nutritional quality
E0 ↓ use of agrochemicals; ↑ probability of off-target impacts
(I) Sustainable intensific. land use D+ ↓ GHG footprint L+ Land sparing
optimisation R- Might ↑ pollution/biodiversity loss
E0 Mixed effects
(I) Agroecology D+ ↓ GHG/area, positive micro-climatic effects E+ Focus on co-benefits/ecosystem services
E+ ↓ energy, possibly ↓ transport R+ Circular, ↑ nutrient and water use efficiencies
FL+ Circular approaches
Controlled (T) Soilless agriculture D+ ↑ productivity, weather independent R+ Controlled loops ↑ nutrient and water use efficiency
environment L+ Land sparing
agriculture FL+ Harvest on demand H+ Crop breeding can be optimised for taste and/or nutritional
quality
E- Currently ↑ energy demand, but ↓ transport, building spaces
can be used for renewable energy
Emerging (T) Insects D0 Good feed conversion efficiency H0 Good nutritional qualities but attention to allergies and food
Food safety issues required
Production FW+ Can be fed on food waste
technologies
(I/T) Algae and bivalves D+ ↓ GHG footprints A+ Animal welfare
L+ Land sparing
H+ Good nutritional qualities; risk of heavy metal and pathogen
contamination
R+ Biofiltration of nutrient-polluted waters
(I/T) Plant-based alternatives to D+ No emissions from animals, ↓ inputs for feed A+ Animal welfare
animal-based food products L+ Land sparing
H+ Potentially ↓ risk from zoonotic diseases, pesticides and
antibiotics; but ↑ processing demand
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Food system mitigation options (I: incremental; T: Direct and indirect effect on GHG mitigation Co-benefits / Adverse effects b
transformative) (+/0/-) a
(T) Cellular agriculture (including D+ No emissions from animals, high protein conversion efficiency A+ Animal welfare
cultured meat, microbial protein) E- ↑ energy need R+ ↓ emissions of reactive nitrogen or other pollutants
FLW+ ↓ food loss & waste H0 Potentially ↓ risk from zoonotic diseases, pesticides and
antibiotics; ↑ research on safety aspects needed
Food (I) Valorisation of by-products, M+ Substitution of bio-based materials
processing and FLW logistics and management FL+ ↓ of food losses
packaging
(I) Food conservation FW+ ↓ of food waste
E0 ↑ energy demand but also energy savings possible (e.g.,
refrigeration, transport)
(I) Smart packaging and other FW+ ↓ of food waste H+ Possibly ↑ freshness/reduced food safety risks
technologies M0 ↑ material demand and ↑ material-efficiency
E0 ↑ energy demand; energy savings possible
(I) Energy efficiency E+ ↓ energy
Storage and (I) Improved logistics D+ ↓ transport emissions
distribution FL+ ↓ losses in transport
FW- Easier access to food could ↑ food waste
(I) Specific measures to reduce food FW+↓ of food waste
waste in retail and food catering E+ ↓ downstream energy demand
M+ ↓ downstream material demand
(I) Alternative fuels/transport modes D+ ↓ emissions from transport
(I) Energy efficiency E+ ↓ energy in refrigeration, lightening, climatisation
(I) Replacing refrigerants D+ ↓ emissions from the cold chain
1
2 a. Direct and indirect GHG effects: D – direct emissions except emissions from energy use, E – energy demand, M – material demand, FL – food losses, FW – food waste;
3 direction of effect on GHG mitigation: (+) increased mitigation, (0) neutral, (-) decreased mitigation.
4 b. Co-benefits/Adverse effects: H - health aspects, A - animal welfare, R - resource use, L - land demand, E – ecosystem services; (+) co-benefits, (-) adverse effects. {Table
5 12.8}
6
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1
2
3 Table TS.6 Assessment of food system policies targeting (post-farm gate) food chain actors and consumers
Transformative
Feasibility
effective.
potential
Environ.
Level Distributional
effects Cost Co-benefitsa and adverse side-effect Implications for coordination, coherence and consistency in policy package b
Integrated food can be Cost + balanced, addresses multiple Reduces cost of uncoordinated interventions; increases acceptance across
NL
policy packages controlled efficient sustainability goals stakeholders and civil society (high confidence).
Taxes on food High enforcing effect on other food policies; higher acceptance if compensation or
GN regressive low#1 - unintended substitution effects
products hypothecated taxes (medium evidence, high agreement).
-unintended substitution effects Supportive, enabling effect on other food policies, agricultural/fishery policies;
GHG taxes on food GN regressive low#2 requires changes in power distribution and trade agreements
+high spillover effect (medium confidence).
impacts global complex + counters leakage effects Requires changes in existing trade agreements (medium evidence, high
Trade policies G
distribution effects +/- effects on market structure and jobs agreement).
Investment into + high spillover effect Can fill targeted gaps for coordinated policy packages (e.g. monitoring methods)
GN none medium
research & innovation + converging with digital society (high confidence).
Food and marketing Can be supportive; might be supportive to realise innovation; voluntary standards
N low
regulations might be less effective (medium confidence).
Organisational level + can address multiple sustainability Enabling effect on other food policies; reaches large share of population (medium
NL low
procurement policies goals evidence, high agreement).
Sustainable food-
+ can address multiple sustainability Little attention so far on environmental aspects; can serve as benchmark for other
based dietary GNL none low
goals policies (labels, food formulation standards, etc.) (medium confidence).
guidelines
+ empowers citizens Effective mainly as part of a policy package; incorporation of other objectives
Food labels/ education level
GNL low + increases awareness (e.g., animal welfare, fair trade...); higher effect if mandatory
information relevant
+ multiple objectives (medium confidence).
+ possibly counteracting information
Nudges NL none low High enabling effect on other food policies (medium evidence, high agreement).
deficits in population subgroups
4
5 Color code: Effect of measures: negative , none/unclear p , slightly positive e , positive ; Level: G: global/multinational, N: national, L: local; #1 Minimum level
6 to be effective 20% price increase; #2 Minimum level to be effective 50-80 USD tCO2-eq-1.
7 a. In addition, all interventions are assumed to address health and climate change mitigation.
8 b. Requires coordination between policy areas, participation of stakeholders, transparent methods and indicators to manage trade-offs and prioritisation between possibly
9 conflicting objectives; and suitable indicators for monitoring and evaluation against objectives. {Table 12.9}
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1 TS. 5.7 Carbon dioxide removal (CDR)
2 CDR is a key element in scenarios that likely limit warming to 2°C or 1.5°C by 2100 (high
3 confidence). Implementation strategies need to reflect that CDR methods differ in terms of removal
4 process, timescale of carbon storage, technological maturity, mitigation potential, cost, co-benefits,
5 adverse side-effects, and governance requirements. (Box TS.10)
6 All the illustrative mitigation pathways (IMPs) assessed in this report use land-based biological
7 CDR (primarily afforestation/reforestation (A/R)) and/or bioenergy with carbon capture and
8 storage (BECCS). Some also include direct air CO2 capture and storage (DACCS) (high
9 confidence). Across the scenarios likely limiting warming to 2°C or below, cumulative volumes22 of
10 BECCS reach 328 (168–763) GtCO2, net CO2 removal on managed land (including A/R) reaches 252
11 (20–418) GtCO2, and DACCS reaches 29 (0–339) GtCO2, for the 2020-2100 period. Annual volumes
12 in 2050 are 2.75 (0.52–9.45) GtCO2 yr-1 for BECCS, 2.98 (0.23–6.38) GtCO2 yr-1 for the net CO2
13 removal on managed land (including A/R), and 0.02 (0 -1.74) GtCO2 yr-1 for DACCS. (Box TS.10)
14 {12.3, Cross-Chapter Box 8 in Chapter 12}
15 Despite limited current deployment, estimated mitigation potentials for DACCS, enhanced
16 weathering (EW) and ocean-based CDR methods (including ocean alkalinity enhancement and
17 ocean fertilisation) are moderate to large (medium confidence). The potential for DACCS (5–40
18 GtCO2 yr-1) is limited mainly by requirements for low-carbon energy and by cost (100-300 (full range:
19 84–386) USD tCO2-1). DACCS is currently at a medium technology readiness level. EW has the
20 potential to remove 2–4 (full range: <1 to ~100) GtCO2 yr-1, at costs ranging from 50 to 200 (full range:
21 24–578) USD tCO2-1. Ocean-based methods have a combined potential to remove 1–100 GtCO2 yr-1 at
22 costs of USD40–500 tCO2-1, but their feasibility is uncertain due to possible side-effects on the marine
23 environment. EW and ocean-based methods are currently at a low technology readiness level. {12.3}
24 CDR governance and policymaking can draw on widespread experience with emissions reduction
25 measures (high confidence). Additionally, to accelerate research, development, and demonstration,
26 and to incentivise CDR deployment, a political commitment to formal integration into existing climate
27 policy frameworks is required, including reliable measurement, reporting and verification MRV of
28 carbon flows. {12.3.3, 12.4, 12.5}
29
30 START BOX TS.10 HERE
31 Box TS.10: Carbon Dioxide Removal
32 Carbon Dioxide Removal (CDR) is necessary to achieve net zero CO2 and GHG emissions both globally
33 and nationally, counterbalancing ‘hard-to-abate’ residual emissions. CDR is also an essential element
34 of scenarios that limit warming to 1.5°C or likely below 2°C by 2100, regardless of whether global
35 emissions reach near zero, net zero or net negative levels. While national mitigation portfolios aiming
36 at net zero emissions or lower will need to include some level of CDR, the choice of methods and the
37 scale and timing of their deployment will depend on the achievement of gross emission reductions, and
38 managing multiple sustainability and feasibility constraints, including political preferences and social
39 acceptability.
40 CDR refers to anthropogenic activities removing CO2 from the atmosphere and durably storing it in
41 geological, terrestrial, or ocean reservoirs, or in products. It includes existing and potential
42 anthropogenic enhancement of biological, geochemical or chemical CO2 sinks, but excludes natural
43 CO2 uptake not directly caused by human activities (Annex I). Carbon Capture and Storage (CCS) and
FOOTNOTE 22 As a median value (5 to 95% range).
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1 Carbon Capture and Utilisation (CCU) applied to fossil CO2 do not count as removal technologies. CCS
2 and CCU can only be part of CDR methods if the CO2 is biogenic or directly captured from ambient
3 air, and stored durably in geological reservoirs or products. {12.3}
4 There is a great variety of CDR methods and respective implementation options {Cross-Chapter Box 8
5 Figure 1 in Chapter 12}. Some of these methods (like afforestation and soil-carbon sequestration) have
6 been practiced for decades to millennia, although not necessarily with the intention to remove carbon
7 from the atmosphere. Conversely, for methods such as DACCS and BECCS, experience is growing but
8 still limited in scales. A categorisation of CDR methods can be based on several criteria, depending on
9 the highlighted characteristics. In this report, the categorisation is focused on the role of CDR methods
10 in the carbon cycle, i.e. on the removal process (land-based biological; ocean-based biological;
11 geochemical; chemical) and on the timescale of storage (decades to centuries; centuries to millennia;
12 10 thousand years or longer), the latter being closely linked to different carbon storage media. Within
13 one category (e.g., ocean-based biological CDR) options often differ with respect to other dynamic or
14 context-specific dimensions such as mitigation potential, cost, potential for co-benefits and adverse
15 side-effects, and technology readiness level. (Table TS.7; TS 5.6, 5.7) {12.3}
16 It is useful to distinguish between CO2 removal from the atmosphere as the outcome of deliberate
17 activities implementing CDR options, and the net emissions outcome achieved with the help of CDR
18 deployment (i.e., gross emissions minus gross removals). As part of ambitious mitigation strategies at
19 global or national levels, gross CDR can fulfil three different roles in complementing emissions
20 abatement: (1) lowering net CO2 or GHG emissions in the near-term; (2) counterbalancing ‘hard-to-
21 abate’ residual emissions like CO2 from industrial activities and long-distance transport, or CH4 and
22 nitrous oxide from agriculture, in order to help reach net zero CO2 or GHG emissions in the mid-term;
23 (3) achieving net negative CO2 or GHG emissions in the long-term if deployed at levels exceeding
24 annual residual emissions {2.7, 3.3, 3.4, 3.5}. These roles of CDR are not mutually exclusive: for
25 example, achieving net zero CO2 or GHG emissions globally might involve individual developed
26 countries attaining net negative CO2 emissions at the time of global net zero, thereby allowing
27 developing countries a smoother transition. {Cross-Chapter Box 8 Figure 2 in Chapter 12}
28 END BOX TS.10 HERE
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1 Table TS.7: Summary of status, costs, potentials, risk and impacts, co-benefits, trade-offs and spill over effects and the role in mitigation pathways for CDR
2 methods {12.3.2, 7.4} TRL = Technology Readiness Level
CDR option Status Cost (USD Mitigation Risk and Impacts Co-benefits Trade-offs and spill over Role in mitigation Section
(TRL) tCO2-1) Potential effects pathways
(GtCO2 yr-
1
)
Afforestation/Reforestation (8-9) 0-240 0.5-10 Reversal of carbon removal through wildfire, Enhanced employment and local Inappropriate deployment at Substantial contribution in {7.4}
disease, pests may occur. livelihoods, improved biodiversity, large scale can lead to IAMs and also in bottom-
Reduced catchment water yield and lower improved renewable wood products competition for land with up sectoral studies.
groundwater level if species and biome are provision, soil carbon and nutrient biodiversity conservation and
inappropriate. cycling. Possibly less pressure on food production.
primary forest.
Soil Carbon Sequestration in (8-9) 45-100 0.6-9.3 Risk of increased nitrous oxide emissions due to Improved soil quality, resilience and Attempts to increase carbon In development – not yet {7.4}
croplands and grasslands higher levels of organic nitrogen in the soil; risk of agricultural productivity. sequestration potential at the in global mitigation
reversal of carbon sequestration. expense of production. Net pathways simulated by
addition per hectare is very IAMs in bottom-up
small; hard to monitor. studies: with medium
contribution.
Peatland and coastal wetland (8-9) Insufficient 0.5-2.1 Reversal of carbon removal in drought or future Enhanced employment and local Competition for land for food Not in IAMs but some {7.4}
restoration data disturbance. Risk of increased CH4 emissions. livelihoods, increased productivity of production on some peatlands bottom-up studies with
fisheries, improved biodiversity, soil used for food production. medium contribution.
carbon and nutrient cycling.
Agroforestry (8-9) Insufficient 0.3-9.4 Risk that some land area lost from food Enhanced employment and local Some trade off with No data from IAMs, but in {7.4}
data production; requires very high skills. livelihoods, variety of products agricultural crop production, bottom-up sectoral studies
improved soil quality, more resilient but enhanced biodiversity, and with medium contribution.
systems. resilience of system.
Improved Forest (8-9) Insufficient 0.1-2.1 If improved management is understood as merely In case of sustainable forest If it involves increased fertiliser No data from IAMs, but in {7.4}
management data intensification involving increased fertiliser use management, it leads to enhanced use and introduced species it bottom-up sectoral studies
and introduced species, then it could reduce employment and local livelihoods, could reduce biodiversity and with medium contribution.
biodiversity and increase eutrophication. enhanced biodiversity, improved increase eutrophication and
productivity. upstream GHG emissions.
Biochar (6-7) 10-345 0.3-6.6 Particulate and GHG emissions from production; Increased crop yields and reduced Environmental impacts In development – not yet {7.4}
biodiversity and carbon stock loss from non-CO2 emissions from soil; and associated particulate matter; in global mitigation
unsustainable biomass harvest. resilience to drought. competition for biomass pathways simulated by
resource. IAMs.
DACCS 6 100-300 5-40 Increased energy and water use. Water produced (solid sorbent DAC Potentially increased emissions In a few IAMs; DACCS {12.3}
(84–386) designs only). from water supply and energy complements other CDR
generation. methods.
BECCS (5-6) 15-400 0.5-11 Inappropriate deployment at very large- scale Reduction of air pollutants; fuel Competition for land with Substantial contribution in {7.4}
leads to additional land and water use to grow security, optimal use of residues, biodiversity conservation and IAMs and bottom -up
biomass feedstock. Biodiversity and carbon stock additional income, health food production. sectoral studies. Note-
loss if from unsustainable biomass harvest. benefits and if implemented well can mitigation through avoided
enhance biodiversity. GHG emissions resulting
from the bioenergy use is
of the same magnitude as
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CDR option Status Cost (USD Mitigation Risk and Impacts Co-benefits Trade-offs and spill over Role in mitigation Section
(TRL) tCO2-1) Potential effects pathways
(GtCO2 yr-
1
)
the mitigation from CDR
(TS.5.6).
Enhanced weathering 3-4 50-200 (24- 2-4 (<1-95) Mining impacts; air quality impacts of rock dust Enhanced plant growth, reduced Potentially increased emissions In a few IAMs; EW {12.3}
578) when spreading on soil. erosion, enhanced soil carbon, from water supply and energy complements other CDR
reduced pH, soil water retention. generation. methods.
"Blue carbon" in coastal 2-3 Insufficient <1 If degraded or lost, coastal blue carbon ecosystems Provide many non-climatic benefits Not incorporated in IAMs, {7.4,
wetlands data are expected to release most of their carbon back and can contribute to ecosystem- but in some bottom-up 12.3.1}
to the atmosphere; potential for sediment based adaptation, coastal protection, studies: small contribution.
contaminants, toxicity, bioaccumulation and increased biodiversity, reduced upper
biomagnification in organisms; issues related to ocean acidification; could potentially
altering degradability of coastal plants; use of benefit human nutrition or produce
subtidal areas for tidal wetland carbon removal; fertiliser for terrestrial agriculture,
effect of shoreline modifications on sediment anti-methanogenic feed additive, or
redeposition and natural marsh accretion; abusive as an industrial or materials
use of coastal blue carbon as means to reclaim feedstock.
land for purposes that degrade capacity for carbon
removal.
Ocean fertilisation 1-2 50-500 1-3 Nutrient redistribution, restructuring of the Increased productivity and fisheries, Subsurface ocean acidification, No data. {12.3.1}
ecosystem, enhanced oxygen consumption and reduced upper ocean acidification. deoxygenation; altered
acidification in deeper waters, potential for meridional supply of macro-
decadal-to-millennial-scale return to the nutrients as they are utilised in
atmosphere of nearly all the extra carbon removed, the iron-fertilised region and
risks of unintended side effects. become unavailable for
transport to, and utilisation in
other regions, fundamental
alteration of food webs,
biodiversity.
Ocean alkalinity 1-2 40–260 1–100 Increased seawater pH and saturation states and Limiting ocean acidification. Potentially increased emissions No data. {12.3.1}
enhancement may impact marine biota. Possible release of of CO2 and dust from mining,
nutritive or toxic elements and compounds. transport and deployment
Mining impacts. operations.
1 Range based on authors’ estimates (as assessed from literature) are shown, with full literature ranges shown in brackets
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1 TS. 5.8 Demand-side aspects of mitigation
2 The assessment of the social science literature and regional case studies reveals how social norms,
3 culture, and individual choices interact with infrastructure and other structural changes over time. This
4 provides new insight into climate change mitigation strategies, and how economic and social activity
5 might be organised across sectors to support emission reductions. To enhance well-being, people
6 demand services and not primary energy and physical resources per se. Focusing on demand for services
7 and the different social and political roles people play broadens the participation in climate action. (Box
8 TS.11)
9 Demand-side mitigation and new ways of providing services can help Avoid and Shift final service
10 demands and Improve service delivery. Rapid and deep changes in demand make it easier for
11 every sector to reduce GHG emissions in the short and medium term (high confidence). {5.2, 5.3}
12 The indicative potential of demand-side strategies across all sectors to reduce emissions is 40-70%
13 by 2050 (high confidence). Technical mitigation potentials compared to the International Energy
14 Agency’s 2020 World Energy Outlook STEPS (Stated Policy Scenarios) baseline are up to 5.7 GtCO2-eq for
15 building use and construction, 8 GtCO2-eq for food demand, 6.5 GtCO2-eq for land transport, and 5.2
16 GtCO2-eq for industry. Mitigation strategies can be classified as Avoid-Shift-Improve (ASI) options,
17 that reflect opportunities for socio-cultural, infrastructural, and technological change. The greatest
18 Avoid potential comes from reducing long-haul aviation and providing short-distance low-carbon urban
19 infrastructures. The greatest Shift potential would come from switching to plant-based diets. The
20 greatest Improve potential comes from within the building sector, and in particular increased use of
21 energy efficient end-use technologies and passive housing. (Figure TS.20, Figure TS.21) {5.3.1, 5.3.2,
22 Figure 5.7, Figure 5.8, Table 5.1, Table SM 5.2}
23 Socio-cultural and lifestyle changes can accelerate climate change mitigation (medium
24 confidence). Among 60 identified actions that could change individual consumption, individual
25 mobility choices have the largest potential to reduce carbon footprints. Prioritising car-free mobility by
26 walking and cycling and adoption of electric mobility could save 2 tCO2-eq cap-1 yr-1. Other options
27 with high mitigation potential include reducing air travel, cooling setpoint adjustments, reduced
28 appliance use, shifts to public transit, and shifting consumption towards plant-based diets. {5.3.1,
29 5.3.1.2, Figure 5.8}
30
31 START BOX TS.11 HERE
32 Box TS.11: A New Chapter in WG III AR6 Focusing on the Social Science of Demand, and
33 Social Aspects of Mitigation
34 The WG III contribution to the Sixth Assessment Report of the IPCC (AR6) features a distinct chapter
35 on demand, services and social aspects of mitigation {5}. The scope, theories, and evidence for such an
36 assessment are addressed in Sections 5.1 and 5.4 within Chapter 5 and a Social Science Primer as an
37 Appendix to Chapter 5.
38 The literature on social science – from sociology, psychology, gender studies and political science for
39 example – and climate change mitigation is growing rapidly. A bibliometric search of the literature
40 identified 99,065 peer-reviewed academic papers, based on 34 search queries with content relevant to
41 Chapter 5. This literature is expanding by 15% per year, with twice as many publications in the AR6
42 period (2014-2020) as in all previous years.
43 The models of stakeholders’ decisions assessed by IPCC have continuously evolved. From AR1 to
44 AR4, rational choice was the implicit assumption: agents with perfect information and unlimited
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1 processing capacity maximising self-focused expected utility and differing only in wealth, risk attitude,
2 and time discount rate. AR5 introduced a broader range of goals (material, social, and psychological)
3 and decision processes (calculation-based, affect-based, and rule-based processes). However, its
4 perspective was still individual- and agency-focused, neglecting structural, cultural, and institutional
5 constraints and the influence of physical and social context.
6 A social science perspective is important in two ways. By adding new actors and perspectives, it (i)
7 provides more options for climate mitigation; and (ii) helps to identify and address important social and
8 cultural barriers and opportunities to socioeconomic, technological, and institutional change. Demand-
9 side mitigation involves five sets of social actors: individuals (e.g., consumption choices, habits),
10 groups and collectives (e.g., social movements, values), corporate actors (e.g., investments,
11 advertising), institutions (e.g., political agency, regulations), and infrastructure actors (e.g., very long-
12 term investments and financing). Actors either contribute to the status-quo of a global high-carbon,
13 consumption, and GDP growth-oriented economy, or help generate the desired change to a low-carbon
14 energy-services, well-being, and equity-oriented economy. Each set of actors has novel implications for
15 the design and implementation of both demand- and supply-side mitigation policies. They show
16 important synergies, making energy demand mitigation a dynamic problem where the packaging and/or
17 sequencing of different policies play a role in their effectiveness {5.5, 5.6}. Incremental interventions
18 change social practices, simultaneously affecting emissions and well-being. The transformative change
19 requires coordinated action across all five sets of actors (Table 5.4), using social science insights about
20 intersection of behaviour, culture, institutional and infrastructural changes for policy design and
21 implementation. Avoid, Shift, and Improve choices by individuals, households and communities support
22 mitigation {5.3.1.1, Table 5.1}. They are instigated by role models, changing social norms driven by
23 policies and social movements. They also require appropriate infrastructures designed by urban
24 planners and building and transport professionals, corresponding investments, and a political culture
25 supportive of demand side mitigation action.
26 END BOX TS.11 HERE
27
28 Leveraging improvements in end-use service delivery through behavioural and technological
29 innovations, and innovations in market organisation, leads to large reductions in upstream
30 resource use (high confidence). Analysis of indicative potentials range from a factor 10- to 20-fold
31 improvement in the case of available energy (exergy) analysis, with the highest improvement potentials
32 at the end-user and service-provisioning levels. Realisable service level efficiency improvements could
33 reduce upstream energy demand by 45% in 2050. (Figure TS.20) {5.3.2, Figure 5.10}
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1
2 Figure TS.20: Demand-side strategies for mitigation. Demand-side mitigation is about more than
3 behavioural change and transformation happens through societal, technological and institutional changes
4 {Figure 5.10, Figure 5.14}
5
6
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1
2 Figure TS.21: Demand-side mitigation can be achieved through changes in socio-cultural factors,
3 infrastructure design and use, and technology adoption
4 Figure TS.21 legend: Mitigation response options related to demand for services have been categorised into
5 three domains: ‘socio-cultural factors’, related to social norms, culture, and individual choices and behaviour;
6 ‘infrastructure use’, related to the provision and use of supporting infrastructure that enables individual choices
7 and behaviour; and ‘technology adoption’, which refers to the uptake of technologies by end users.
8 Potentials in 2050 are estimated using the International Energy Agency’s 2020 World Energy Outlook STEPS
9 (Stated Policy Scenarios) as a baseline. This scenario is based on a sector-by-sector assessment of specific
10 policies in place, as well as those that have been announced by countries by mid-2020. This scenario was
11 selected due to the detailed representation of options across sectors and sub-sectors.
12 The heights of the coloured columns represent the potentials on which there is a high level of agreement in the
13 literature, based on a range of case studies. The range shown by the dots connected by dotted lines represents the
14 highest and lowest potentials reported in the literature which have low to medium levels of agreement.
15 The demand side potential of socio-cultural factors in the food system has two parts. The economic potential of
16 direct emissions (mostly non-CO2) demand reduction through socio-cultural factors alone is 1.9 GtCO2eq
17 without considering land use change by diversion of agricultural land from food production to carbon
18 sequestration. If further changes in land use enabled by this change in demand are considered, the indicative
19 potential could reach 7 GtCO2eq.
20 The electricity panel presents separately the mitigation potential from changes in electricity demand and
21 changes associated with enhanced electrification in end use sectors. Electrification increases electricity demand,
22 while it is avoided though demand-side mitigation strategies. Load management refers to demand side flexibility
23 that can be achieved through incentive design like time of use pricing/monitoring by artificial intelligence,
24 diversification of storage facilities etc. NZE (IEA Net Zero Emissions by 2050 Scenario) is used to compute the
25 impact of end use sector electrification, while the impact of demand side response options is based on bottom-up
26 assessments.
27 Dark grey columns show the emissions that cannot be avoided through demand-side mitigation options.
28 The table indicates which demand-side mitigation options are included. Options are categorised according to:
29 socio-cultural factors, infrastructure use, and technology adoption.
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1 Figure SPM.7 covers potential of demand-side options for the year 2050. Figure SPM.8 covers both supply- and
2 demand-side options and their potentials for the year 2030.
3 {5.3, Figure 5.7, Supplementary Material 5.II}
4
5 Decent living standards (DLS) and well-being for all (SDG 3) are achievable if high-efficiency low-
6 demand mitigation pathways are followed (medium confidence). Minimum requirements of energy
7 use consistent with enabling well-being for all is between 20 and 50 GJ cap-1 yr-1 depending on the
8 context. (Figure TS.22) {5.2.2.1, 5.2.2.2, Box 5.3}
9 Alternative service provision systems, for example those enabled through digitalisation, sharing
10 economy initiatives and circular economy initiatives, have to date made a limited contribution to
11 climate change mitigation (medium confidence). While digitalisation through specific new products
12 and applications holds potential for improvement in service-level efficiencies, without public policies
13 and regulations, it also has the potential to increase consumption and energy use. Reducing the energy
14 use of data centres, networks, and connected devices is possible in managing low-carbon digitalisation.
15 Claims on the benefits of the circular economy for sustainability and climate change mitigation have
16 limited evidence. (Box TS.12, Box TS.14) {5.3.4, Figure 5.12, Figure 5.13}
17
18 START BOX TS.12 HERE
19 Box TS.12: Circular Economy (CE)
20 In AR6, the Circular Economy (CE) concept {Annex I} is highlighted as an increasingly important
21 mitigation approach that can help deliver human well-being by minimising waste of energy and
22 resources. While definitions of CE vary, its essence is to shift away from linear “make and dispose”
23 economic models to those that emphasize product longevity, reuse, refurbishment, recycling, and
24 material efficiency, thereby enabling more circular material systems that reduce embodied energy and
25 emissions. {5.3.4, 8.4, 8.5, 9.5, 11.3.3}
26 Whereas IPCC AR4 {WG III, Chapter 10} included a separate chapter on waste sector emissions and
27 waste management practices, and AR5 {WG III, Chapter 10} reviewed the importance of “reduce,
28 reuse, recycle” and related policies, AR6 focuses on how CE can reduce waste in materials production
29 and consumption by optimising materials’ end-use service utility. Specific examples of CE
30 implementations, policies, and mitigation potentials are included in chapters 5, 8, 9, 11 and 12. {5.3,
31 8.4, 9.5, 11.3, 12.6}
32 CE is shown to empower new social actors in mitigation actions, given that it relies on the synergistic
33 actions of producers, sellers, and consumers {11.3.3}. As an energy and resource demand-reduction
34 strategy, it is consistent with high levels of human well-being {5.3.4.3} and ensures better
35 environmental quality (Figure TS.22) {5.2.1}. It also creates jobs through increased sharing, reuse,
36 refurbishment, and recycling activities. Therefore, CE contributes to several SDGs, including Clean
37 Water and Sanitation (SDG6), Affordable Energy and Clean Energy (SDG7), Decent Work and
38 Economic Growth (SDG8), Responsible Production and Consumption (SDG12) and Climate Action
39 (SDG13). {11.5.3.2}
40 Emissions savings derive from reduced primary material production and transport. For example, in
41 buildings, lifetime extension, material efficiency, and reusable components reduce embodied emissions
42 by avoiding demand for structural materials {9.3, 9.5}. At regional scales, urban/industrial symbiosis
43 reduce primary material demand through byproduct exchange networks {11.3.3}. CE strategies also
44 exhibit enabling effects, such as material-efficient and circular vehicle designs that also improve fuel
45 economy {10.2.2.2}. There is growing interest in “circular bioeconomy” concepts applied to bio-based
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1 materials {Box 12.2} and even a “circular carbon economy”, wherein carbon captured via CCU
2 {11.3.6} or CDR {3.4.6} is converted into reusable materials, which is especially relevant for the
3 transitions of economies dependent on fossil fuel revenue. {12.6}
4 While there are many recycling policies, CE-oriented policies for more efficient material use with
5 higher value retention are comparatively far fewer; these policy gaps have been attributed to
6 institutional failures, lack of coordination, and lack of strong advocates {5.3, 9.5.3.6, Box 11.5, Box
7 12.2}. Reviews of mitigation potentials reveal unevenness in the savings of CE applications and
8 potential risks of rebound effects {5.3}. Therefore, CE policies that identify system determinants
9 maximize potential emissions reductions, which vary by material, location, and application.
10 There are knowledge gaps for assessing CE opportunities within mitigation models due to CE’s many
11 cross-sectoral linkages and data gaps related to its nascent state {3.4.4}. Opportunity exists to bridge
12 knowledge from the Industrial Ecology field, which has historically studied CE, to the mitigation
13 modelling community for improved analysis of interventions and policies for AR7. For instance, a
14 global CE knowledge sharing platform is helpful for CE performance measurement, reporting and
15 accounting. {5.3, 9.5, 11.7}
16 END BOX TS.12 HERE
17
18 Providing better services with less energy and resource input has high technical potential and is
19 consistent with providing well-being for all (medium confidence). The assessment of 19 demand-
20 side mitigation options and 18 different constituents of well-being showed that positive impacts on well-
21 being outweigh negative ones by a factor of 11. {5.2, 5.2.3, Figure 5.6}
22 Demand-side mitigation options bring multiple interacting benefits (high confidence). Energy
23 services to meet human needs for nutrition, shelter, health, etc. are met in many different ways with
24 different emissions implications that depend on local contexts, cultures, geography, available
25 technologies, and social preferences. In the near term, many less-developed countries, and poor people
26 everywhere, require better access to safe and low-emissions energy sources to ensure decent living
27 standards and increase energy savings from service improvements by about 20-25%. (Figure TS.22)
28 {5.2, 5.4.5, Figure 5.3, Figure 5.4, Figure 5.5, Figure 5.6, Box 5.2, Box 5.3}
29 Granular technologies and decentralized energy end-use, characterised by modularity, small unit
30 sizes and small unit costs, diffuse faster into markets and are associated with faster technological
31 learning benefits, greater efficiency, more opportunities to escape technological lock-in, and
32 greater employment (high confidence). Examples include solar PV systems, batteries, and thermal
33 heat pumps. {5.3, 5.5, 5.5.3}
34 Wealthy individuals contribute disproportionately to higher emissions and have a high potential
35 for emissions reductions while maintaining decent living standards and well-being (high
36 confidence). Individuals with high socio-economic status are capable of reducing their GHG emissions
37 by becoming role models of low-carbon lifestyles, investing in low-carbon businesses, and advocating
38 for stringent climate policies. {5.4.1, 5.4.3, 5.4.4, Figure 5.14}
39 Demand-side solutions require both motivation and capacity for change (high confidence).
40 Motivation by individuals or households worldwide to change energy consumption behaviour is
41 generally low. Individual behavioural change is insufficient for climate change mitigation unless
42 embedded in structural and cultural change. Different factors influence individual motivation and
43 capacity for change in different demographics and geographies. These factors go beyond traditional
44 socio-demographic and economic predictors and include psychological variables such as awareness,
45 perceived risk, subjective and social norms, values, and perceived behavioural control. Behavioural
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1 nudges promote easy behaviour change, e.g., “Improve” actions such as making investments in energy
2 efficiency but fail to motivate harder lifestyle changes (high confidence). {5.4}
3 Behavioural interventions, including the way choices are presented to end users (an intervention
4 practice known as choice architecture), work synergistically with price signals, making the
5 combination more effective (medium confidence). Behavioural interventions through nudges, and
6 alternative ways of redesigning and motivating decisions, alone provide small to medium contributions
7 to reduce energy consumption and GHG emissions. Green defaults, such as automatic enrolment in
8 “green energy” provision, are highly effective. Judicious labelling, framing, and communication of
9 social norms can also increase the effect of mandates, subsidies, or taxes. {5.4, 5.4.1, Table 5.3, 5.3}
10 Cultural change, in combination with new or adapted infrastructure, is necessary to enable and
11 realise many Avoid and Shift options (medium confidence). By drawing support from diverse actors,
12 narratives of change can enable coalitions to form, providing the basis for social movements to
13 campaign in favour of (or against) societal transformations. People act and contribute to climate change
14 mitigation in their diverse capacities as consumers, citizens, professionals, role models, investors, and
15 policymakers. {5.4, 5.5, 5.6}
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1
2
3 Figure TS.22: Demand side mitigation options, well-being and SDGs {Figure 5.6}
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1 Collective action as part of social or lifestyle movements underpins system change (high
2 confidence). Collective action and social organising are crucial to shift the possibility space of public
3 policy on climate change mitigation. For example, climate strikes have given voice to youth in more
4 than 180 countries. In other instances, mitigation policies allow the active participation of all
5 stakeholders, resulting in building social trust, new coalitions, legitimising change, and thus initiate a
6 positive cycle in climate governance capacity and policies. {5.4.2, Figure 5.14}
7 Transition pathways and changes in social norms often start with pilot experiments led by
8 dedicated individuals and niche groups (high confidence). Collectively, such initiatives can find
9 entry points to prompt policy, infrastructure, and policy reconfigurations, supporting the further uptake
10 of technological and lifestyle innovations. Individuals’ agency is central as social change agents and
11 narrators of meaning. These bottom-up socio-cultural forces catalyse a supportive policy environment,
12 which enables changes. {5.5.2}
13 The current effects of climate change, as well as some mitigation strategies, are threatening the
14 viability of existing business practices, while some corporate efforts also delay mitigation action
15 (medium confidence). Policy packages that include job creation programs can help to preserve social
16 trust, livelihoods, respect, and dignity of all workers and employees involved. Business models that
17 protect rent extracting behaviour may sometimes delay political action. Corporate advertisement and
18 brand building strategies may also attempt to deflect corporate responsibility to individuals or aim to
19 appropriate climate care sentiments in their own brand–building. {5.4.3, 5.6.4}
20 Middle actors – professionals, experts, and regulators – play a crucial albeit underestimated and
21 underutilised role in establishing low-carbon standards and practices (medium confidence).
22 Building managers, landlords, energy efficiency advisers, technology installers, and car dealers
23 influence patterns of mobility and energy consumption by acting as middle actors or intermediaries in
24 the provision of building or mobility services and need greater capacity and motivation to play this role.
25 (Figure TS.20a) {5.4.3}
26 Social influencers and thought leaders can increase the adoption of low-carbon technologies,
27 behaviours, and lifestyles (high confidence). Preferences are malleable and can align with a cultural
28 shift. The modelling of such shifts by salient and respected community members can help bring about
29 changes in different service provisioning systems. Between 10% and 30% of committed individuals are
30 required to set new social norms. {5.2.1, 5.4}
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1 TS. 5.9 Mitigation potential across sectors and systems
2 The total emission mitigation potential achievable by the year 2030, calculated based on sectoral
3 assessments, is sufficient to reduce global greenhouse gas emissions to half of the current (2019)
4 level or less (high confidence). This potential – 31 to 44 GtCO2-eq – requires the implementation of a
5 wide range of mitigation options. Options with mitigation costs lower than USD20 tCO2-1 make up
6 more than half of this potential and are available for all sectors. The market benefits of some options
7 exceed their costs. (Figure TS.23) {12.2, Table 12.3}
8 Cross-sectoral considerations in mitigation finance are critical for the effectiveness of mitigation
9 action as well as for balancing the often conflicting social, developmental, and environmental
10 policy goals at the sectoral level (medium confidence). True resource mobilisation plans that properly
11 address mitigation costs and benefits at sectoral level cannot be developed in isolation of their cross-
12 sectoral implications. There is an urgent need for multilateral financing institutions to align their
13 frameworks and delivery mechanisms including the use of blended financing to facilitate cross-sectoral
14 solutions as opposed to causing competition for resources among sectors. {12.6.4}
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1
2
3 Figure TS.23: Overview of emission mitigation options and their cost and potential for the year 2030.
4
5 Figure TS.23 legend: The mitigation potential of each option is the quantity of net greenhouse gas emission
6 reductions that can be achieved by a given mitigation option relative to specified emission baselines that reflects
7 what would be considered current policies in the period 2015-2019. Mitigation options may overlap or interact
8 and cannot simply be summed together.
9 The potential for each option is broken down into cost categories (see legend). Only monetary costs and
10 revenues are considered. If costs are less than zero, lifetime monetary revenues are higher than lifetime
11 monetary costs. For wind energy, for example, negative cost indicates that the cost is lower than that of fossil-
12 based electricity production. The error bars refer to the total potential for each option. The breakdown into cost
13 categories is subject to uncertainty. Where a smooth colour transition is shown, the breakdown of the potential
14 into cost categories is not well researched, and the colours indicate only into which cost category the potential
15 can predominantly be found in the literature.
16 {Figure SPM.8, 6.4, Table 7.3, Supplementary Material Table 9.2, Supplementary Material Table 9.3, 10.6,
17 11.4, Fig 11.13, 12.2, Supplementary Material 12.A.2.3}
18
19 Carbon leakage is a cross-sectoral and cross-country consequence of differentiated climate policy
20 (robust evidence, medium agreement). Carbon leakage occurs when mitigation measures implemented
21 in one country/sector leads to increased emissions in other countries/sectors. Global commodity value
22 chains and associated international transport are important mechanisms through which carbon leakage
23 occurs. Reducing emissions from the value chain and transportation can offer opportunities to mitigate
24 three elements of cross-sectoral spill-overs and related leakage: 1) domestic cross-sectoral spill-overs
25 within the same country; 2) international spill-overs within a single sector resulting from substitution
26 of domestic production of carbon-intensive goods with their imports from abroad; and 3) international
27 cross-sectoral spill-overs among sectors in different countries. {12.6.3}
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1 TS. 6 Implementation and enabling conditions
2 Chapters 13-16 address the enabling conditions that can accelerate or impede rapid progress on
3 mitigation. Chapters 13 and 14 focus on policy, governance and institutional capacity, and international
4 cooperation, respectively taking a national and international perspective; Chapter 15 focusses on
5 investment and finance; and Chapter 16 focusses on innovation and technology. The assessment of
6 social aspects of mitigation draws on material assessed in Chapter 5.
7 TS. 6.1 Policy and Institutions
8 Long-term deep emission reductions, including the reduction of emissions to net zero, is best
9 achieved through institutions and governance that nurture new mitigation policies, while at the
10 same time reconsidering existing policies that support the continued emission of GHGs (high
11 confidence). To do so effectively, the scope of climate governance needs to include both direct efforts
12 to target GHG emissions and indirect opportunities to tackle GHG emissions that result from efforts
13 directed towards other policy objectives. {13.2, 13.5, 13.6, 13.7, 13.9}
14 Institutions and governance underpin mitigation by providing the legal basis for action. This
15 includes setting up implementing organisations and the frameworks through which diverse actors
16 interact (medium evidence, high agreement). Institutions can create mitigation and sectoral policy
17 instruments; policy packages for low-carbon system transition; and economy wide measures for
18 systemic restructuring. {13.2, 13.7, 13.9}
19 Policies have had a discernible impact on mitigation for specific countries, sectors, and
20 technologies (high confidence), avoiding emissions of several GtCO2-eq yr-1 (medium confidence).
21 Both market-based and regulatory policies have distinct, but complementary roles. The share of global
22 GHG emissions subject to mitigation policy has increased rapidly in recent years, but big gaps remain
23 in policy coverage, and the stringency of many policies falls short of what is needed to achieve the
24 desired mitigation outcomes. (Box TS.13) {13.6, Cross-Chapter Box 10 in Chapter 14}
25 Climate laws enable mitigation action by signalling the direction of travel, setting targets,
26 mainstreaming mitigation into sector policies, enhancing regulatory certainty, creating law-
27 backed agencies, creating focal points for social mobilisation, and attracting international finance
28 (medium evidence, high agreement). By 2020, ‘direct’ climate laws primarily focused on GHG
29 reductions were present in 56 countries covering 53% of global emissions (see Figure TS.24). More
30 than 690 laws, including ‘indirect’ laws, however, may also have an effect on mitigation. Among direct
31 laws, ‘framework’ laws set an overarching legal basis for mitigation either by pursuing a target and
32 implementation approach, or by seeking to mainstream climate objectives through sectoral plans and
33 integrative institutions. (Figure TS.24) {13.2}
34 Institutions can enable improved governance by coordinating across sectors, scales and actors,
35 building consensus for action, and setting strategies (medium evidence, high agreement).
36 Institutions are more stable and effective when they are congruent with national contexts, leading to
37 mitigation-focused institutions in some countries and the pursuit of multiple objectives in others. Sub-
38 national institutions play a complementary role to national institutions by developing locally-relevant
39 visions and plans, addressing policy gaps or limits in national institutions, building local administrative
40 structures and convening actors for place-based decarbonisation. {13.2}
41 Mitigation strategies, instruments and policies that fit with dominant ideas, values and belief
42 systems within a country or within a sector are more easily adopted and implemented (medium
43 confidence). Ideas, values and beliefs may change over time. Policies that bring perceived direct
44 benefits, such as subsidies, usually receive greater support. The awareness of co-benefits for the public
45 increases support of climate policies (high confidence). {13.2, 13.3, 13.4}
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1
2 Panel a
3
4 Panel b
5
6
7 Figure TS.24: Prevalence of Legislation and Emissions Targets across Regions
8
9 Figure TS.24 legend: Panel a: Shares of global GHG emissions under national climate change legislations – in
10 2010, 2015 and 2020. Climate legislation is defined as an act passed by a parliament that includes the reduction
11 of GHGs in its title or objectives.
12 Panel b: Shares of global GHG emissions under national climate emission targets – in 2010, 2015 and 2020.
13 Emissions reductions targets were taken into account as a legislative target when they were defined in a law or
14 as part of a country's submission under the Kyoto Protocol, or as an executive target when they were included in
15 a national policy or official submissions under the UNFCCC. Targets were included if they were economy wide
16 or included at least the energy sector. The proportion of national emissions covered are scaled to reflect
17 coverage and whether targets are in GHG or CO2 terms.
18 Emissions data used are for 2019. 2020 data was excluded as emissions shares across regions deviated from past
19 patterns due to COVID-19. AR6 regions: DEV = Developed countries; APC = Asia and developing Pacific;
20 EEA = Eastern Europe and West-Central Asia; AFR = Africa; LAM = Latin America and the Caribbean; MDE
21 = Middle East. {Figure 13.1 and 13.2}
22 .
23 Climate governance is constrained and enabled by domestic structural factors, but it is still
24 possible for actors to make substantial changes (medium evidence, high agreement). Key structural
25 factors are domestic material endowments (such as fossil fuels and land-based resources); domestic
26 political systems; and prevalent ideas, values and belief systems. Developing countries face additional
27 material constraints in climate governance due to development challenges and scarce economic or
28 natural resources. A broad group of actors influence how climate governance develop over time,
29 including a range of civic organisations, encompassing both pro- and anti-climate action groups. {13.3,
30 13.4}
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1 Sub-national actors are important for mitigation because municipalities and regional
2 governments have jurisdiction over climate-relevant sectors such as land-use, waste and urban
3 policy. They are able to experiment with climate solutions and can forge partnerships with the
4 private sector and internationally to leverage enhanced climate action (high confidence). More
5 than 10,500 cities and nearly 250 regions representing more than 2 billion people have pledged largely
6 voluntary action to reduce emissions. Indirect gains include innovation, establishing norms and
7 developing capacity. However, sub-national actors often lack national support, funding, and capacity to
8 mobilize finance and human resources, and create new institutional competences. {13.5}
9 Climate litigation is growing and can affect the outcome and ambition of climate governance
10 (medium evidence, high agreement). Since 2015, at least 37 systemic cases have been initiated against
11 states that challenge the overall effort of a state to mitigate or adapt to climate change. If successful,
12 such cases can lead to an increase in a country’s overall ambition to tackle climate change. Climate
13 litigation has also successfully challenged governments’ authorisations of high-emitting projects setting
14 precedents in favour of climate action. Climate litigation against private sector and financial institutions
15 is also on the rise. {13.4}
16 The media shapes the public discourse about climate mitigation. This can usefully build public
17 support to accelerate mitigation action but may also be used to impede decarbonisation (medium
18 evidence, high agreement). Global media coverage (across a study of 59 countries) has been growing,
19 from about 47,000 articles in 2016-17 to about 87,000 in 2020-21. Generally, the media representation
20 of climate science has increased and become more accurate over time. On occasion, the propagation of
21 scientifically misleading information by organized counter-movements has fuelled polarisation, with
22 negative implications for climate policy. {13.4}
23 Explicit attention to equity and justice is salient to both social acceptance and fair and effective
24 policymaking for mitigation (high confidence). Distributional implications of alternative climate
25 policy choices can be usefully evaluated at city, local and national scales as an input to policymaking.
26 It is anticipated that institutions and governance frameworks that enable consideration of justice and
27 just transitions can build broader support for climate policymaking. {13.2, 13.6, 13.8, 13.9}
28 Carbon pricing is effective in promoting implementation of low-cost emissions reductions (high
29 confidence). While the coverage of emissions trading and carbon taxes has risen to over 20 percent of
30 global CO2 emissions, both coverage and price are lower than is needed for deep reductions. Market
31 mechanisms ideally are designed to be effective as well as efficient, balance distributional goals and
32 find social acceptance. Practical experience has driven progress in market mechanism design, especially
33 of emissions trading schemes. Carbon pricing is limited in its effect on adoption of higher-cost
34 mitigation options, and where decisions are often not sensitive to price incentives such as in energy
35 efficiency, urban planning, and infrastructure (robust evidence, medium agreement). Subsidies have
36 been used to improve energy efficiency, encourage the uptake of renewable energy and other sector-
37 specific emissions saving options {13.6}
38 Carbon pricing is most effective if revenues are redistributed or used impartially (high
39 confidence). A carbon levy earmarked for green infrastructures or saliently returned to taxpayers
40 corresponding to widely accepted notions of fairness increases the political acceptability of carbon
41 pricing. {5.6, Box 5.11}
42 Removing fossil fuel subsidies could reduce emissions by 1-10% by 2030 while improving public
43 revenue and macroeconomic performance (robust evidence, medium agreement). {13.6}
44 Regulatory instruments play an important role in achieving specific mitigation outcomes in
45 sectoral applications (high confidence). Regulation is effective in particular applications and often
46 enjoys greater political support, but tends to be more economically costly, than pricing instruments
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1 (robust evidence, medium agreement). Flexible forms of regulation (e.g., performance standards) have
2 achieved aggregate goals for renewable energy generation, vehicle efficiency and fuel standards, and
3 energy efficiency in buildings and industry. Infrastructure investment decisions are significant for
4 mitigation because they lock in high- or low- emissions trajectories over long periods. Information and
5 voluntary programs can contribute to overall mitigation outcomes (medium evidence, high agreement).
6 Designing for overlap and interactions among mitigation policies enhances their effectiveness. {13.6}
7 National mitigation policies interact internationally with effects that both support and hinder
8 mitigation action (medium evidence, high agreement). Reductions in demand for fossil fuels tend to
9 negatively affect fossil fuel exporting countries. Creation of markets for emission reduction credits
10 tends to benefit countries able to supply credits. Policies to support technology development and
11 diffusion tend to have positive spill over effects. There is no consistent evidence of significant emissions
12 leakage or competitiveness effects between countries, including for emissions-intensive trade-exposed
13 industries covered by emission trading systems (medium confidence). {13.6}
14 Policy packages are better able to support socio-technical transitions and shifts in development
15 pathways toward low carbon futures than are individual policies (high confidence). For best effect,
16 they need to be harnessed to a clear vision for change and designed with attention to local governance
17 context. Comprehensiveness in coverage, coherence to ensure complementarity, and consistency of
18 policies with the overarching vision and its objectives are important design criteria. Integration across
19 objectives occurs when a policy package is informed by a clear problem framing and identification of
20 the full range of relevant policy sub-systems. The climate policy landscape is outlined in Table TS.8,
21 which maps framings of desired national policy outcomes to policymaking approaches. {13.7, Figure
22 13.6}
23 The co-benefits and trade-offs of integrating adaptation and mitigation are most usefully
24 identified and assessed prior to policy making rather than being accidentally discovered (high
25 confidence). This requires strengthening relevant national institutions to reduce silos and overlaps,
26 increasing knowledge exchange at the country and regional levels, and supporting engagement with
27 bilateral and multilateral funding partners. Local governments are well placed to develop policies that
28 generate social and environmental co-benefits but to do so require legal backing and adequate capacity
29 and resources. {13.8}
30 Climate change mitigation is accelerated when attention is given to integrated policy and economy
31 wide approaches, and when enabling conditions (governance, institutions, behaviour and lifestyle,
32 innovation, policy, and finance), are present (robust evidence, medium agreement). Accelerating
33 climate mitigation includes simultaneously weakening high carbon systems and encouraging low
34 carbon systems; ensuring interaction between adjacent systems (e.g., energy and agriculture);
35 overcoming resistance to policies (e.g., from incumbents in high carbon emitting industries), including
36 by providing transitional support to the vulnerable and negatively affected by distributional impacts;
37 inducing changes in consumer practices and routines; providing transition support; and addressing
38 coordination challenges in policy and governance. Table TS.9 elucidates the complexity of
39 policymaking in driving sectoral transitions by summarising case studies of sectoral transitions from
40 Chapters 5-12. These real-world sectoral transitions reinforce critical lessons on policy integration.
41 (Table TS.9) {13.7, 13.9}
42 Economy wide packages, including economic stimulus packages, can contribute to shifting
43 sustainable development pathways and achieving net zero outcomes whilst meeting short term
44 economic goals (medium evidence, high agreement). The 2008-9 Global Recession showed that
45 policies for sustained economic recovery go beyond short-term fiscal stimulus to include long-term
46 commitments of public spending on the low carbon economy, pricing reform, addressing affordability,
47 and minimising distributional impacts. COVID-19 spurred stimulus packages and multi-objective
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1 recovery policies may also have potential to meet short-term economic goals while enabling longer-
2 term sustainability goals. (Table TS.8) {13.9}
3
4
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1
2 Table TS.8: Mapping the Landscape of Climate Policy {Figure 13.6}
3
Framing of Outcome
Enhancing Mitigation Addressing Multiple Objectives of Mitigation and Development
“Direct Mitigation Focus” “Co-benefits”
{2.8, 13.6} {5.6.2, 12.4.4, 17.3}
Objective: Reduce GHG emissions now Objective: Synergies between mitigation and development
Shifting Literature: How to design and implement policy Literature: Scope for and policies to realise synergies and avoid trade-
Incentives instruments, with attention to distributional and other offs across climate and development objectives
concerns Examples: Appliance standards, fuel taxes, community forest
Examples: Carbon tax, cap and trade, border carbon management, sustainable dietary guidelines, green building codes,
adjustment, disclosure policies packages for air pollution, packages for public transport
“Socio-technical transitions” “System transitions to shift development pathways”
Approach to {1.7.3, 5.5, 6.7, 10.8, Cross-Chapter Box 12 in Chapter 16) {7.4.5, 11.6.6, 13.9, 17.3.3, Cross-Chapter Box 5 in Chapter 4, Cross-
Policymaking Chapter Box 12 in Chapter 16}
Objective: Accelerate low-carbon shifts in socio-technical Objective: Accelerate system transitions and shift development
systems pathways to expand mitigation options and meet other development
Enabling Literature: Understand socio-technical transition processes, goals
Transition integrated policies for different stages of a technology ‘S Literature: Examines how structural development patterns and broad
curve’ and explore structural, social and political elements cross-sector and economy wide measures drive ability to mitigate
of transitions while achieving development goals through integrated policies and
Examples: Packages for renewable energy transition and aligning enabling conditions
coal phase-out; diffusion of electric vehicles, process and Examples: Packages for sustainable urbanisation, land-energy-water
fuel switching in key industries nexus approaches, green industrial policy, regional just transition plans
4
5
6
7
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1 Table TS.9: Case Studies of Integrated Policymaking for Sectoral Transitions
2 Real world sectoral transitions reinforce critical lessons on policy integration: a high-level strategic goal (column A), the need for a clear sectoral outcome
3 framing (column B), a carefully coordinated mix of policy instruments and governance actions (column C), and the importance of context-specific
4 governance factors (column D). Illustrative examples, drawn from sectors, help elucidate the complexity of policymaking in driving sectoral transitions.
A. Illustrative D. Governance Context
B. Objective C. Policy mix
Case Enablers Barriers
- Strengthen co-ordination between modes
- Cultural norms around informal transport sharing,
- Formalize and green auto-rickshaws - Complexity: multiple modes with separate
Shift in mobility - Improve system efficiency, linked to high levels of social trust
- Procure fuel efficient, comfortable low floor AC networks and meanings
service provision in sustainability and comfort - Historically crucial role of buses in transit
buses - Pushback from equity-focused social
Kolkata, India {Box - Shift public perceptions of - App-cab companies shifting norms and formalizing
- Ban cycling on busy roads movements against 'premium' fares, cycling
5.8} public transport mobility sharing
- Deploy policy actors as change-agents, ban
- Digitalisation and safety on board
mediating between interest groups
LPG Subsidy ("Zero - Subsidize provision of Liquefied Petroleum Gas - Provincial Government and industry support in - Continued user preference for traditional
Decrease fiscal expenditures
Kero") Program, (LPG) cylinders and initial equipment targeting beneficiaries and implementation solid fuels
on kerosene subsidies for
Indonesia {Box - Convert existing kerosene suppliers to LPG - Synergies in kerosene and LPG distribution - Reduced GHG benefits as subsidy shifted
cooking
6.3} suppliers infrastructures between fossil fuels
Action Plan for - Expand protected areas; homologation of
- Participatory agenda-setting process - Political polarisation leading to erosion of
Prevention and indigenous lands
Control deforestation and - Cross-sectoral consultations on conservation environmental governance
Control of - Improve inspections, satellite-based monitoring
promote sustainable guidelines - Reduced representation and independence of
Deforestation in the - Restrict public credit for enterprises and
development -Mainstreaming of deforestation in government civil society in decision-making bodies
Legal Amazon, municipalities with high deforestation rates
programs and projects - Lack of clarity around land ownership
Brazil {Box 7.9} - Set up a REDD+ mechanism (Amazon Fund)
- Promote sustainable
- Distribute shade tree seedlings - Local resource governance mechanisms ensuring
intensification of cocoa - Lack of secure tenure (tree rights)
Climate smart cocoa - Provide access to agronomic information and voice for smallholders
production - Bureaucratic and legal hurdles to register
(CSC) production, agro-chemical inputs - Community governance allowed adapting to local
- Reduce deforestation trees
Ghana {Box 7.12} - Design a multi-stakeholder program including context
- Enhance incomes and - State monopoly on cocoa marketing, export
MNCs, farmers and NGOs - Private sector role in popularising CSC
adaptive capacities
Coordination - Combine central targets and evaluation with - Strong vertical linkages between central and local
Integrate policymaking across - Challenging starting point - low share of
mechanism for local flexibility for initiating varied policy levels
objectives, towards low- renewable energy high dependency on fossil
joining fragmented experiments - Mandate for policy learning to inform national
carbon urban development fuels
urban policymaking - Establish a local leadership team for coordinating policy
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A. Illustrative D. Governance Context
B. Objective C. Policy mix
Case Enablers Barriers
in Shanghai, China cross-sectoral policies involving multiple - Experience with mainstreaming mitigation in related - Continued need for high investments in a
{Box 8.3} institutions areas (e.g., air pollution) developing context
- Create a direct program fund for implementation
and capacity-building
- Energy performance standards, set at nearly zero - Binding EU-level targets, directives and sectoral
Policy package for Reduce energy consumption, energy for new buildings effort sharing regulations - Inadequate local technical capacity to
building energy integrating renewable energy - Energy performance standards for appliances - Supportive urban policies, coordinated through city implement multiple instruments
efficiency, EU {Box and mitigating GHG emissions - Energy performance certificates shown during partnerships - Complex governance structure leading to
SM 9.1} from buildings sale - Funds raised from allowances auctioned under the uneven stringency
- Long Term Renovation Strategies Emissions Trading Scheme (ETS)
African
Electromobility- - Economic decline in the first decade of the
- Leapfrog into a decarbonised - Develop urban centres with solar at station - ‘Achieving SDGs’ was an enabling policy framing
Trackless trams 21st century
transport future precincts - Multi-objective policy process for mobility,
with solar in - Limited fiscal capacity for public funding of
- Achieve multiple social - Public-private partnerships for financing mitigation and manufacturing
Bulawayo and e- infrastructure
benefits beyond mobility - Sanction demonstration projects for new electric - Potential for funding through climate finance
motorbikes in - Inadequate charging infrastructure for e-
provision transit and new electric motorbikes (for freight) - Co-benefits such as local employment generation
Kampala {Box motorbikes
10.4}
Initiative for a
- Collaboratively develop - Build platform to bring together industry,
climate-friendly - NRW is Germany's industrial heartland, with an
innovative strategies towards a scientists and government in self-organised
industry in North export-oriented industrial base - Compliance rules preventing in-depth co-
net zero GHG industrial innovation teams
Rhine Westphalia - Established government-industry ties operation
sector, while securing - Intensive cross-branch cooperation to articulate
(NRW), Germany - Active discourse between industry and public
competitiveness policy/infrastructure needs
{Box 11.3}
- Target funding and knowledge support for
- Local, organic and climate - Weak role of integrated impact assessments
innovations
friendly food production - Year-long deliberative stakeholder engagement to inform agenda-setting
- Apply administrative means (legislation,
Food2030 Strategy, - Responsible and healthy food process across sectors - Monitoring and evaluation close to ministry
guidance) to increase organic food production and
Finland {Box 12.2} consumption - Institutional structures for agenda-setting, guiding in charge
procurement
- A competitive food supply policy implementation and reflexive discussions - Lack of standardised indicators of food
- Use education and information instruments to
chain system sustainability
shift behaviour (media campaigns, websites)
1
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1 START BOX TS.13 HERE
2 Box TS.13: Policy Attribution – Methodologies for- and estimations of- the macro-level impact
3 of mitigation policies on indices of GHG mitigation
4 Policy attribution examines the extent to which GHG emission reductions, the proximate drivers of
5 emissions, and the deployment of technologies that reduce emissions may be reasonably attributed to
6 policies implemented prior to the observed changes. Such policies include regulatory instruments such
7 as energy efficiency programmes or technical standards and codes, carbon pricing, financial support for
8 low-carbon energy technologies and efficiency, voluntary agreements, and regulation of land use
9 practices.
10 The vast majority of literature reviewed for this report examines the effect of particular instruments in
11 particular contexts {13.6, 14.3, 16.4}, and only a small number directly or plausibly infer global impacts
12 of policies. Policies also differ in design, scope, and stringency, may change over time as they require
13 amendments or new laws, and often partially overlap with other instruments. These factors complicate
14 analysis, because they give rise to the potential for double counting emissions reductions that have been
15 observed. These lines of evidence on the impact of polices include:
16 • GHG Emissions – Evidence from econometric assessments of the impact of policies in
17 countries which took on Kyoto Protocol targets; decomposition analyses that identify policy-
18 related, absolute reductions from historical levels in particular countries. {13.6.2, 14.3.3, Cross-
19 Chapter Box 10 in Chapter 14}
20 • Proximate emission drivers – trends in the factors that drive emissions including reduced rates
21 of deforestation {7.6.2}, industrial energy efficiency {Box 16.3}, buildings energy efficiency
22 {Figure 2.22}, and the policy-driven displacement of fossil fuel combustion by renewable
23 energy. (Box TS.13 Table 1, Box TS.13 Figure 1) {Chapters 2 and 6, Cross-Chapter Box 10 in
24 Chapter 14}.
25 • Technologies – the literature indicates unambiguously that the rapid expansion of low-carbon
26 energy technologies is substantially attributable to policy. {6.7.5, 16.5}
27 As illustrated in Box TS.13, Figure 1, these multiple lines of evidence indicate that point to policies
28 having had a discernible impact on mitigation for specific countries, sectors, and technologies (high
29 confidence), avoiding emissions of several GCO2-eq yr-1 globally (medium confidence).
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1 Box TS.13 Table 1: The effects of policy on GHG emissions, drivers of emissions, and
2 technology deployment
Effects on Effects on Immediate Effects on Low-
Sector
Emissions Drivers carbon Technology
Energy supply Carbon pricing, Carbon pricing and technology A variety of market-based
{Chapter 6} emissions standards, support have led to improvements in instruments, especially
and technology support the efficiency of energy conversion technology support
have led to declining policies have led to high
emissions associated diffusion rates and cost
with the supply of reductions for renewable
energy energy technologies.
AFOLU Regulation of land-use Regulation of land-use rights and
{Chapter 7} rights and practices practices, payments for ecosystem
have led to falling service, and offsets have led to
aggregate AFOLU- decreasing rates of deforestation
sector emissions (medium confidence)
Buildings Regulatory standards Regulatory standards, financial Technology support and
{Chapter 9} have led to reduced support for building renovation and regulatory standards have
emissions from new market-based instruments have led to led to adoption of low-
buildings improvements in building and carbon heating systems
building system efficiencies and high efficiency
appliances
Transport Vehicle standards, land- Vehicle standard, carbon pricing, and Technology support and
{Chapter 10} use planning, and support for electrification have led to emissions standards have
carbon pricing have led automobile efficiency improvements increased diffusion rates
to avoided emissions in and cost reductions for
ground transportation electric vehicles
Industry Carbon pricing has led to efficiency
{Chapter 11} improvements in industrial facilities.
3 Note: Statements describe the effects of policies across those countries where policies are in place. Unless
4 otherwise noted, all findings are of high confidence
5
6 Box TS.13, Figure 1: Policy impacts on key outcome indices: GHG emissions, proximate emission drivers,
7 and technologies, including several lines of evidence on GHG abatement attributable to policies. {Cross-
8 Chapter Box 10 Figure 1 in Chapter 14}
9 END BOX TS.13 HERE
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1 TS. 6.2 International cooperation
2 International cooperation is having positive and measurable results (high confidence). The Kyoto
3 Protocol led to measurable and substantial avoided emissions, including in 20 countries with Kyoto first
4 commitment period targets that have experienced a decade of declining absolute emissions. It also built
5 national capacity for GHG accounting, catalysed the creation of GHG markets, and increased
6 investments in low-carbon technologies. Other international agreements and institutions have led to
7 avoided CO2 emissions from land-use practices, as well as avoided emissions of some non-CO2
8 greenhouse gases. (medium confidence) {14.3, 14.5, 14.6}
9 New forms of international cooperation have emerged since AR5 in line with an evolving
10 understanding of effective mitigation policies, processes, and institutions. Both new and pre-
11 existing forms of co-operation are vital for achieving climate mitigation goals in the context of
12 sustainable development (high confidence). While previous IPCC assessments have noted important
13 synergies between the outcomes of climate mitigation and achieving sustainable development
14 objectives, there now appear to be synergies between the two processes themselves (medium
15 confidence). Since AR5, international cooperation has shifted towards facilitating national level
16 mitigation action through numerous channels, including though processes established under the
17 UNFCCC regime and through regional and sectoral agreements and organisations. {14.2, 14.3, 14.5,
18 14.6}
19 Participation in international agreements and transboundary networks is associated with the
20 adoption of climate policies at the national and sub-national levels, as well as by non-state actors
21 (high confidence). International cooperation helps countries achieve long-term mitigation targets when
22 it supports development and diffusion of low-carbon technologies, often at the level of individual
23 sectors, which can simultaneously lead to significant benefits in the areas of sustainable development
24 and equity (medium confidence). {14.2, 14.3, 14.5, 14.6}
25 International cooperation under the UN climate regime took an important new direction with the
26 entry into force of the 2015 Paris Agreement, which strengthened the objective of the UN climate
27 regime, including its long-term temperature goal, while adopting a different architecture to that
28 of the Kyoto Protocol (high confidence). The core national commitments under the Kyoto Protocol
29 were legally binding quantified emission targets for developed countries tied to well-defined
30 mechanisms for monitoring and enforcement. By contrast, the commitments under the Paris Agreement
31 are primarily procedural, extend to all parties, and are designed to trigger domestic policies and
32 measures, enhance transparency, and stimulate climate investments, particularly in developing
33 countries, and to lead iteratively to rising levels of ambition across all countries. Issues of equity remain
34 of central importance in the UN climate regime, notwithstanding shifts in the operationalisation of
35 ‘common but differentiated responsibilities and respective capabilities’ from Kyoto to Paris. {14.3}
36 There are conflicting views on whether the Paris Agreement’s commitments and mechanisms will
37 lead to the attainment of its stated goals (medium confidence). Arguments in support of the Paris
38 Agreement are that the processes it initiates and supports will in multiple ways lead, and indeed have
39 already led, to rising levels of ambition over time. The recent proliferation of national mid-century net
40 zero GHG targets can be attributed in part to the Paris Agreement. Moreover, its processes and
41 commitments will enhance countries’ abilities to achieve their stated level of ambition, particularly
42 among developing countries. Arguments against the Paris Agreement are that it lacks a mechanism to
43 review the adequacy of individual Parties’ nationally determined contributions (NDCs), that
44 collectively current NDCs are inconsistent in their level of ambition with achieving the Paris
45 Agreement’s long-term temperature goal, that its processes will not lead to sufficiently rising levels of
46 ambition in the NDCs, and that NDCs will not be achieved because the targets, policies and measures
47 they contain are not legally binding at the international level. To some extent, arguments on both sides
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1 are aligned with different analytic frameworks, including assumptions about the main barriers to
2 mitigation that international cooperation can help overcome. The extent to which countries increase the
3 ambition of their NDCs and ensure they are effectively implemented will depend in part on the
4 successful implementation of the support mechanisms in the Paris Agreement, and in turn will
5 determine whether the goals of the Paris Agreement are met (high confidence). {14.2, 14.3, 14.4}
6 International cooperation outside the UNFCCC processes and agreements provides critical
7 support for mitigation in particular regions, sectors and industries, for particular types of
8 emissions, and at the sub- and trans-national levels (high confidence). Agreements addressing ozone
9 depletion, transboundary air pollution, and release of mercury are all leading to reductions in the
10 emissions of specific greenhouse gases. Cooperation is occurring at multiple governance levels
11 including cities. Transnational partnerships and alliances involving non-state and sub-national actors
12 are also playing a growing role in stimulating low-carbon technology diffusion and emissions
13 reductions (medium confidence). Such transnational efforts include those focused on climate litigation;
14 the impacts of these are unclear but promising. Climate change is being addressed in a growing number
15 of international agreements operating at sectoral levels, as well as within the practices of many
16 multilateral organisations and institutions. Sub-global and regional cooperation, often described as
17 climate clubs, can play an important role in accelerating mitigation, including the potential for reducing
18 mitigation costs through linking national carbon markets, although actual examples of these remain
19 limited. {14.2, 14.4, 14.5, 14.6}
20 International cooperation will need to be strengthened in several key respects in order to support
21 mitigation action consistent with limiting temperature rise to well below 2°C in the context of
22 sustainable development and equity (high confidence). Many developing countries’ NDCs have
23 components or additional actions that are conditional on receiving assistance with respect to finance,
24 technology development and transfer, and capacity building, greater than what has been provided to
25 date. Sectoral and sub-global cooperation is providing critical support, and yet there is room for further
26 progress. In some cases, notably with respect to aviation and shipping, sectoral agreements have
27 adopted climate mitigation goals that fall far short of what would be required to achieve the long-term
28 temperature goal of the Paris Agreement. Moreover, there are cases where international cooperation
29 may be hindering mitigation efforts, namely evidence that trade and investment agreements, as well as
30 agreements within the energy sector, impede national mitigation efforts (medium confidence).
31 International cooperation is emerging but so far fails to fully address transboundary issues associated
32 with solar radiation modification and carbon dioxide removal. {14.2, 14.3, 14.4, 14.5, 14.6, Cross-
33 Working Group Box 4 in Chapter 14}
34
35 TS. 6.3 Societal aspects of mitigation
36 Social equity reinforces capacity and motivation for mitigating climate change (medium
37 confidence). Impartial governance such as fair treatment by law-and-order institutions, fair treatment
38 by gender, and income equity, increases social trust, thus enabling demand-side climate policies. High
39 status (often high carbon) item consumption may be reduced by taxing absolute wealth without
40 compromising well-being. {5.2, 5.4.2, 5.6}
41
42 Policies that increase the political access and participation of women, racialised, and marginalised
43 groups, increase the democratic impetus for climate action (high confidence). Including more
44 differently situated knowledge and diverse perspectives makes climate mitigation policies more
45 effective. {5.2, 5.6}
46
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1 Greater contextualisation and granularity in policy approaches better addresses the challenges
2 of rapid transitions towards zero-carbon systems (high confidence). Larger systems take more time
3 to evolve, grow, and change compared to smaller ones. Creating and scaling up entirely new systems
4 takes longer than replacing existing technologies and practices. Late adopters tend to adopt faster than
5 early pioneers. Obstacles and feasibility barriers are high in the early transition phases. Barriers decrease
6 as a result of technical and social learning processes, network building, scale economies, cultural
7 debates, and institutional adjustments. {5.5, 5.6}
8
9 Mitigation policies that integrate and communicate with the values people hold are more
10 successful (high confidence). Values differ between cultures. Measures that support autonomy, energy
11 security and safety, equity and environmental protection, and fairness resonate well in many
12 communities and social groups. Changing from a commercialised, individualised, entrepreneurial
13 training model to an education cognizant of planetary health and human well-being can accelerate
14 climate change awareness and action. {5.4.1, 5.4.2}
15
16 Changes in consumption choices that are supported by structural changes and political action
17 enable the uptake of low-carbon choices (high confidence). Policy instruments applied in
18 coordination can help to accelerate change in a consistent desired direction. Targeted technological
19 change, regulation, and public policy can help in steering digitalisation, the sharing economy, and
20 circular economy towards climate change mitigation. (Box TS.12, Box TS.14) {5.3, 5.6}
21
22 Complementarity in policies helps in the design of an optimal demand-side policy mix (medium
23 confidence). In the case of energy efficiency, for example, this may involve CO2 pricing, standards and
24 norms, and information feedback. {5.3, 5.4, 5.6}
25
26
27
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1 TS. 6.4 Investment and finance
2 Finance to reduce net GHG emissions and enhance resilience to climate impacts is a critical
3 enabling factor for the low carbon transition. Fundamental inequities in access to finance as well
4 as finance terms and conditions, and countries’ exposure to physical impacts of climate change
5 overall, result in a worsening outlook for a global just transition (high confidence). Decarbonising
6 the economy requires global action to address fundamental economic inequities and overcome the
7 climate investment trap that exists for many developing countries. For these countries the costs and
8 risks of financing often represent a significant challenge for stakeholders at all levels. This challenge is
9 exacerbated by these countries’ general economic vulnerability and indebtedness. The rising public
10 fiscal costs of mitigation, and of adapting to climate shocks, is affecting many countries and worsening
11 public indebtedness and country credit ratings at a time when there were already significant stresses on
12 public finances. The COVID-19 pandemic has made these stresses worse and tightened public finances
13 still further. Other major challenges for commercial climate finance include: the mismatch between
14 capital and investment needs, home bias23 considerations, differences in risk perceptions for regions, as
15 well as limited institutional capacity to ensure safeguards are effective. (high confidence) {15.2, 15.6.3}
16 Investors, central banks, and financial regulators are driving increased awareness of climate risk.
17 This increased awareness can support climate policy development and implementation (high
18 confidence). {15.2, 15.6} Climate-related financial risks arise from physical impacts of climate change
19 (already relevant in the short term), and from a disorderly transition to a low carbon economy.
20 Awareness of these risks is increasing, leading also to concerns about financial stability. Financial
21 regulators and institutions have responded with multiple regulatory and voluntary initiatives to assess
22 and address these risks. Yet despite these initiatives, climate-related financial risks remain greatly
23 underestimated by financial institutions and markets, limiting the capital reallocation needed for the
24 low-carbon transition. Moreover, risks relating to national and international inequity – which act as a
25 barrier to the transformation – are not yet reflected in decisions by the financial community. Stronger
26 steering by regulators and policy makers has the potential to close this gap. Despite the increasing
27 attention of investors to climate change, there is limited evidence that this attention has directly
28 impacted emission reductions. This leaves high uncertainty, both near-term (2021-30) and longer-term
29 (2021-50), on the feasibility of an alignment of financial flows with the Paris Agreement goals (high
30 confidence). {15.2, 15.6}
31 Progress on the alignment of financial flows with low GHG emissions pathways remains slow.
32 There is a climate financing gap which reflects a persistent misallocation of global capital (high
33 confidence) {15.2, 15.3}. Persistently high levels of both public and private fossil-fuel related financing
34 continue to be of major concern despite promising recent commitments. This reflects policy
35 misalignment, the current perceived risk-return profile of fossil fuel-related investments, and political
36 economy constraints (high confidence). Estimates of climate finance flows24 exhibit highly divergent
37 patterns across regions and sectors and a slowing growth {15.3}. When the perceived risks are too high,
38 the misallocation of abundant savings persists and investors refrain from investing in infrastructure and
39 industry in search of safer financial assets, even earning low or negative real returns. (high confidence)
40 {15.2, 15.3}
41
FOOTNOTE 23 Most of climate finance stays within national borders, especially private climate flows (over 90%).
The reasons for this range from national policy support, differences in regulatory standards, exchange rate,
political and governance risks, to information market failures.
FOOTNOTE 24 Climate finance flows refers to local, national, or transnational financing from public, private, and
alternative sources, to support mitigation and adaptation actions addressing climate change.
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1 Global climate finance is heavily focused on mitigation (more than 90% on average between 2017-
2 2020) (high confidence) {15.4, 15.5}. This is despite the significant economic effects of climate
3 change’s expected physical impacts, and the increasing awareness of these effects on financial stability.
4 To meet the needs for rapid deployment of mitigation options, global mitigation investments are
5 expected to need to increase by the factor of three to six (high confidence). The gaps represent a major
6 challenge for developing countries, especially Least Developed Countries (LDCs), where flows have to
7 increase by the factor of four to eight for specific sectors like AFOLU, and for specific groups with
8 limited access to, and high costs of, climate finance (high confidence) (Figure TS.25) {15.4, 15.5}. The
9 actual size of sectoral and regional climate financing gaps is only one component driving the magnitude
10 of the challenge. Financial and economic viability, access to capital markets, appropriate regulatory
11 frameworks, and institutional capacity to attract and facilitate investments and ensure safeguards are
12 decisive to scaling-up funding. Soft costs for regulatory environment and institutional capacity,
13 upstream funding needs as well as R&D and venture capital for development of new technologies and
14 business models are often overlooked despite their critical role to facilitate the deployment of scaled-
15 up climate finance (high confidence). {15.4.1, 15.5.2}
16
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1
2
3
4 Figure TS.25: Mitigation investment flows fall short of investment needs across all sectors and types of economy, particularly in developing countries.
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1
2 Figure TS.25 legend: Breakdown of average mitigation investment flows and investment needs until 2030
3 (USD billion). Given the multiple sources and lack of harmonised methodologies, the data presented here can be
4 considered only as indicative of the size and pattern of investment gaps. For full information of sources see
5 chapter 15 Figure 15.4. Mitigation investment flows and investment needs shown by sector (energy efficiency,
6 transport, electricity, and agriculture, forestry and land use), by type of economy, and by region (see Annex II
7 Part I Section 1 for the classification schemes for countries and areas). Blue bars display data on mitigation
8 investment flows for four years: 2017, 2018, 2019 and 2020 by sector and by type of economy. For the regional
9 breakdown, the annual average mitigation investment flows for 2017-2019 are shown. The grey bars show the
10 minimum and maximum level of global annual mitigation investment needs in the assessed scenarios averaged
11 until 2030. Multiplication factors show the ratio of global average yearly mitigation investment needs (averaged
12 until 2030) and current yearly mitigation flows (averaged for 2017-2020). The lower multiplication factor refers
13 to the lower end of the range of investment needs. The upper multiplication factor refers to the upper range of
14 investment needs. Data on mitigation investment flows does not include technical assistance (i.e., policy and
15 national budget support or capacity building) and other non-technology deployment financing. Adaptation
16 pegged transactions are also excluded. Data on mitigation investment needs does not include needs for
17 infrastructure investment or investment related to meeting the SDGs. {15.3, 15.4, 15.5, Table 15.2, Table 15.3,
18 Table 15.4}
19
20 The relatively slow implementation of commitments by countries and stakeholders in the financial
21 sector to scale up climate finance reflects neither the urgent need for ambitious climate action,
22 nor the economic rationale for ambitious climate action (high confidence). Delayed climate
23 investments and financing – and limited alignment of investment activity with the Paris Agreement –
24 will result in significant carbon lock-ins, stranded assets, and other additional costs. This will
25 particularly impact urban infrastructure and the energy and transport sectors (high confidence). A
26 common understanding of debt sustainability and debt transparency, including negative implications of
27 deferred climate investments on future GDP, and how stranded assets and resources may be
28 compensated, has not yet been developed (medium confidence). {15.6}
29 There is a mismatch between capital availability in the developed world and the future emissions
30 expected in developing countries (high confidence). This emphasizes the need to recognize the
31 explicit and positive social value of global cross-border mitigation financing. A significant push for
32 international climate finance access for vulnerable and poor countries is particularly important given
33 these countries’ high costs of financing, debt stress and the impacts of ongoing climate change (high
34 confidence). {15.2, 15.3.2.3, 15.5.2, 15.6.1, 15.6.7}
35 Innovative financing approaches could help reduce the systemic under-pricing of climate risk in
36 markets and foster demand for investment opportunities aligned with the Paris Agreement goals.
37 Approaches include de-risking investments, robust ‘green’ labelling and disclosure schemes, in
38 addition to a regulatory focus on transparency and reforming international monetary system
39 financial sector regulations (medium confidence). Green bond markets and markets for sustainable
40 finance products have grown significantly since AR5 and the landscape continues to evolve.
41 Underpinning this evolution is investors’ preference for scalable and identifiable low-carbon investment
42 opportunities. These relatively new labelled financial products will help by allowing a smooth
43 integration into existing asset allocation models. (high confidence) Green bond markets and markets for
44 sustainable finance products have also increased significantly since AR5, but challenges nevertheless
45 remain, in particular there are concerns about ‘greenwashing’ and the limited application of these
46 markets to developing countries (high confidence). {15.6.2, 15.6.6}
47 New business models (e.g., pay-as-you-go) can facilitate the aggregation of small-scale financing
48 needs and provide scalable investment opportunities with more attractive risk-return profiles
49 (high confidence). Support and guidance for enhancing transparency can promote capital markets’
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1 climate financing by providing quality information to price climate risks and opportunities. Examples
2 include SDG and environmental, social and governance (ESG) disclosure, scenario analysis and climate
3 risk assessments, including the Task Force on Climate-Related Financial Disclosures (TCFD). The
4 outcome of these market-correcting approaches on capital flows cannot be taken for granted, however,
5 without appropriate fiscal, monetary and financial policies. Mitigation policies will be required to
6 enhance the risk-weighted return of low emission and climate resilient options, accelerate the
7 emergence and support for financial products based on real projects, such as green bonds, and phase
8 out fossil fuel subsidies. Greater public-private cooperation can also encourage the private sector to
9 increase and broaden investments, within a context of safeguards and standards, and this can be
10 integrated into national climate change policies and plans (high confidence). {15.1, 15.2.4, 15.3.1,
11 15.3.2, 15.3.3, 15.5.2, 15.6.1, 15.6.2, 15.6.6, 15.6.7, 15.6.8}
12 Ambitious global climate policy coordination and stepped-up public climate financing over the
13 next decade (2021–2030) can help redirect capital markets and overcome challenges relating to
14 the need for parallel investments in mitigation. It can also help address macroeconomic
15 uncertainty and alleviate developing countries’ debt burden post-COVID-19 (high confidence).
16 Providing strong climate policy signals helps guide investment decisions. Credible signalling by
17 governments and the international community can reduce uncertainty for financial decision-makers and
18 help reduce transition risk. In addition to indirect and direct subsidies, the public sector’s role in
19 addressing market failures, barriers, provision of information, and risk sharing can encourage the
20 efficient mobilisation of private sector finance (high confidence). {15.2, 15.6.1, 15.6.2} The mutual
21 benefits of coordinated support for climate mitigation and adaptation in the next decade for both
22 developed and developing regions could potentially be very high in the post-COVID era. Climate
23 compatible stimulus packages could significantly reduce the macro-financial uncertainty generated by
24 the pandemic and increase the sustainability of the world economic recovery. {15.2, 15.3.2.3, 15.5.2,
25 15.6.1, 15.6.7} Political leadership and intervention remain central to addressing uncertainty, which is
26 a fundamental barrier for the redirection of financial flows. Existing policy misalignments – for example
27 in fossil fuel subsidies – undermine the credibility of public commitments, reduce perceived transition
28 risks and limit financial sector action (high confidence). {15.2, 15.3.3, 15.6.1, 15.6.2, 15.6.3}
29 The greater the urgency of action to remain on a 1.5°C pathway, the greater need for parallel
30 investment decisions in upstream and downstream parts of the value chain (high confidence).
31 Greater urgency also reduces the lead times to build trust in regulatory frameworks. Consequently,
32 many investment decisions will need to be made based on the long-term global goals. This highlights
33 the importance of trust in political leadership which, in turn, affects risk perception and ultimately
34 financing costs (high confidence). {15.6.1, 15.6.2}
35 Accelerated international cooperation on finance is a critical enabler of a low-carbon and just
36 transition (very high confidence). Scaled-up public grants for adaptation and mitigation and funding
37 for low-income and vulnerable regions, especially in Sub-Saharan Africa, may have the highest returns.
38 key options include: increased public finance flows from developed to developing countries beyond
39 USD100 billion-a-year; shifting from a direct lending modality towards public guarantees to reduce
40 risks and greatly leverage private flows at lower cost; local capital markets development; and, changing
41 the enabling operational definitions. A coordinated effort to green the post-pandemic recovery is also
42 essential in countries facing much higher debt costs. (high confidence) {15.2, 15.6}
43
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1 TS. 6.5 Innovation, technology development and transfer
2 Innovation in climate mitigation technologies has seen enormous activity and significant progress
3 in recent years. Innovation has also led to, and exacerbated, trade-offs in relation to sustainable
4 development. Innovation can leverage action to mitigate climate change by reinforcing other
5 interventions. In conjunction with other enabling conditions innovation can support system transitions
6 to limit warming and help shift development pathways. The currently widespread implementation of
7 solar PV and LED lighting, for instance, could not have happened without technological innovation.
8 Technological innovation can also bring about new and improved ways of delivering services that are
9 essential to human well-being (high confidence) {16.1, 16.3, 16.4, 16.6}. At the same time as delivering
10 benefits, innovation can result in trade-offs that undermine both progress on mitigation and progress
11 towards other sustainable development goals. Trade-offs include negative externalities – for instance
12 greater environmental pollution and social inequalities – rebound effects leading to lower net emission
13 reductions or even increases in emissions, and increased dependency on foreign knowledge and
14 providers (high confidence). Effective governance and policy have the potential to avoid and minimise
15 such misalignments (medium evidence, high agreement). {16.2, 16.3, 16.4, 16.5.1, 16.6}
16 A systemic view of innovation to direct and organize the processes has grown over the last decade.
17 This systemic view of innovation takes into account the role of actors, institutions, and their
18 interactions and can inform how innovation systems that vary across technologies, sectors and
19 countries, can be strengthened (high confidence) {16.2, 16.3, 16.5}. Where a systemic view of
20 innovation has been taken, it has enabled the development and implementation of indicators that are
21 better able to provide insights in innovation processes. This, in turn, has enabled the analysis and
22 strengthening of innovation systems. Traditional quantitative innovation indicators mainly include
23 R&D investments and patents. Figure TS.26 illustrates that energy-related RD&D has risen slowly in
24 the last two decades, and that there has been a reorientation of the portfolio of funded energy
25 technologies. Systemic indicators of innovation, however, go well beyond these approaches. They
26 include structural innovation system elements including actors and networks, as well as indicators for
27 how innovation systems function, such as access to finance, employment in relevant sectors, and
28 lobbying activities {16.3.4, Table 16.7}. For example, in Latin America, monitoring systemic
29 innovation indicators for the effectiveness of agroecological mitigation approaches has provided
30 insights on the appropriateness and social alignment of new technologies and practices {Box 16.5}.
31 Climate-energy-economy models, including integrated assessment models, generally employ a stylised
32 and necessarily incomplete view of innovation, and have yet to incorporate a systemic representation
33 of innovation systems. {16.2.4, Box 16.1}
34
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1
2 Figure TS.26: Fraction of public energy research, development and demonstration (RD&D (spending by
3 technology over time for IEA (largely OECD) countries between 1974 and 2018. {Box 16.3 Figure 1}
4
5 A systemic perspective on technological change can provide insights to policymakers supporting
6 their selection of effective innovation policy instruments (high confidence) {16.4, 16.5}. A
7 combination of scaled-up innovation investments with demand-pull interventions can achieve faster
8 technology unit cost reductions and more rapid scale-up than either approach in isolation. These
9 innovation policy instruments would nonetheless have to be tailored to local development priorities, to
10 the specific context of different countries, and to the technology being supported. The timing of
11 interventions and any trade-offs with sustainable development also need to be addressed. Public R&D
12 funding and support as well as innovation procurement have shown to be valuable for fostering
13 innovation in small to medium cleantech firms (Figure TS.27) {16.4.4.3}. Innovation outcomes of
14 policy instruments not necessarily aimed at innovation, such as feed-in tariffs, auctions, emissions
15 trading schemes, taxes and renewable portfolio standards, vary from negligible to positive for climate
16 change mitigation. Some specific designs of environmental taxation can also result in negative
17 distributional outcomes {16.4.4}. Most of the available literature and evidence on innovation systems
18 come from industrialised countries and larger developing countries. However, there is a growing body
19 of evidence from developing countries and small island developing states (SIDS). {16.4, 16.5, 16.7}
20
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1
2 Figure TS.27: Technology innovation process and the (illustrative) roles of different public policy
3 instruments (on the right-hand side). {Figure 16.1}
4 Figure TS.27 legend: Note that, demand pull instruments in the regulatory instrument category, for instance,
5 can also shape the early stages of the innovation process. Their position on the latter stages is highlighted in this
6 figure just because typically these instruments have been introduced in latter stages of the development of the
7 technology. {16.4.4}
8 Experience and analyses show that technological change is inhibited if technological innovation
9 system functions are not adequately fulfilled; this inhibition occurs more often in developing
10 countries (high confidence). Examples of such functions are knowledge development, resource
11 mobilisation, and activities that shape the needs, requirements and expectations of actors within the
12 innovation system (guidance of the search). Capabilities play a key role in these functions, the build-up
13 of which can be enhanced by domestic measures, but also by international cooperation. For instance,
14 innovation cooperation on wind energy has contributed to the accelerated global spread of this
15 technology. As another example, the policy guidance by the Indian government, which also promoted
16 development of data, testing capabilities and knowledge within the private sector, has been a key
17 determinant of the success of an energy-efficiency programme for air conditioners and refrigerators in
18 India. {16.3, 16.5, 16.6, Cross-Chapter Box 12 in Chapter 16, Box 16.3}
19 Consistent with innovation system approaches, the sharing of knowledge and experiences
20 between developed and developing countries can contribute to addressing global climate and the
21 SDGs. The effectiveness of such international cooperation arrangements, however, depends on
22 the way they are developed and implemented (high confidence). The effectiveness and sustainable
23 development benefits of technology sharing under market conditions appears to be determined primarily
24 by the complexity of technologies, local capabilities and the policy regime. This suggests that the
25 development of planning and innovation capabilities remains necessary, especially in least-developed
26 countries and SIDS. International diffusion of low-emission technologies is also facilitated by
27 knowledge spill overs from regions engaged in clean R&D (medium confidence). {16.2}
28 The evidence on the role of intellectual property rights (IPR) in innovation is mixed. Some
29 literature suggests that it is a barrier while other sources suggests that it is an enabler to the
30 diffusion of climate-related technologies (medium confidence). There is agreement that countries
31 with well-developed institutional capacity may benefit from a strengthened IPR regime, but that
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1 countries with limited capabilities might face greater barriers to innovation as a consequence. This
2 enhances the continued need for capacity building. Ideas to improve the alignment of the global IPR
3 regime and addressing climate change include specific arrangements for least-developed countries,
4 case-by-case decision-making and patent-pooling institutions. {16.2.3, 16.5, Box 16.10}
5 Although some initiatives have mobilised investments in developing countries, gaps in innovation
6 cooperation remain, including in the Paris Agreement instruments. These gaps could be filled by
7 enhancing financial support for international technology cooperation, by strengthening
8 cooperative approaches, and by helping build suitable capacity in developing countries across all
9 technological innovation system functions (high confidence). The implementation of current
10 arrangements of international cooperation for technology development and transfer, as well as capacity
11 building, are insufficient to meet climate objectives and contribute to sustainable development. For
12 example, despite building a large market for mitigation technologies in developing countries, the lack
13 of a systemic perspective in the implementation of the Clean Development Mechanism, operational
14 since the mid-2000s, has only led to some technology transfer, especially to larger developing countries,
15 but limited capacity building and minimal technology development (medium confidence). In the current
16 climate regime, a more systemic approach to innovation cooperation could be introduced by linking
17 technology institutions, such as the Technology Mechanism, and financial actors, such as the financial
18 mechanism. {16.5.3}
19 Countries are exposed to sustainable development challenges in parallel with the challenges that
20 relate to climate change. Addressing both sets of challenges simultaneously presents multiple and
21 recurrent obstacles that systemic approaches to technological change could help resolve, provided
22 they are well managed (high confidence). Obstacles include both entrenched power relations
23 dominated by vested interests that control and benefit from existing technologies, and governance
24 structures that continue to reproduce unsustainable patterns of production and consumption (medium
25 confidence). Studies also highlight the potential of cultural factors to strongly influence the pace and
26 direction of technological change. Sustainable solutions require adoption and mainstreaming of locally
27 novel technologies that can meet local needs, and simultaneously address the SDGs. Acknowledging
28 the systemic nature of technological innovation – which involve many levels of actors, stages of
29 innovation and scales – can lead to new opportunities to shift development pathways towards
30 sustainability. {16.4, 16.5, 16.6}
31 Strategies for climate change mitigation can be most effective in accelerating transformative
32 change when actions taken to strengthen one set of enabling conditions also reinforce and
33 strengthen the effectiveness of other enabling conditions (medium confidence). Applying transition
34 or system dynamics to decisions can help policy makers take advantage of such high-leverage
35 intervention points, address the specific characteristics of technological stages, and respond to societal
36 dynamics. Inspiration can be drawn from the global unit cost reductions of solar PV, which were
37 accelerated by a combination of factors interacting in a mutually reinforcing way across a limited group
38 of countries (high confidence). {Box 16.2, Cross-Chapter Box 12 in Chapter 16}. Transitions can be
39 accelerated by policies appropriately targeted, which may be grouped in different ‘pillars of policy’.
40 The relative importance of different ‘pillars’ differs according to stage of the transition. (see Figure
41 TS.28) {1.2.3}
42
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1
2 Figure TS.28: Transition dynamics: levels, policies and processes. {Figure 1.7}
3 The relative importance of different ‘pillars of policy’ differs according to stage of the transition. The lower
4 panel illustrates growth of innovative technologies or practices, which if successful, emerge from niches into an
5 S-shape dynamic of exponential growth. The diffusion stage often involves new infrastructure and
6 reconfiguration of existing market and regulatory structures. During the phase of more widespread diffusion,
7 growth levels off to linear, then slows as the industry and market matures. The processes displace incumbent
8 technologies/practices which decline, initially slowly but then at an accelerating pace. Many related literatures
9 identify three main levels with different characteristics, most generally termed micro, meso and macro.
10
11 Better and more comprehensive data on innovation indicators can provide timely insights for
12 policy makers and policy design locally, nationally and internationally, especially for developing
13 countries, where such insights are often missing. Data needed include those that can show the
14 strength of technological, sectoral and national innovation systems. It is also necessary to validate
15 current results and generate insights from theoretical frameworks and empirical studies for developing
16 countries’ contexts. Innovation studies on adaptation and mitigation other than energy and ex-post
17 assessments of the effectiveness of various innovation-related policies and interventions, including
18 R&D, would also provide benefits. Furthermore, methodological developments to improve the ability
19 of IAMs to capture energy innovation system dynamics and the relevant institutions and policies
20 (including design and implementation), would allow for more realistic assessment. {16.2, 16.3, 16.7}
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1 START BOX TS.14 HERE
2 Box TS.14 Digitalisation
3 Digital technologies can promote large increases in energy efficiency through coordination and an
4 economic shift to services, but they can also greatly increase energy demand because of the energy used
5 in digital devices (high confidence). {Cross-Chapter Box 11 in Chapter 16, 16.2}
6 Digital devices, including servers, increase pressure on the environment due to the demand for rare
7 metals and end-of-life disposal. The absence of adequate governance in many countries can lead to
8 harsh working conditions and unregulated disposal of electronic waste. Digitalisation also affects firms'
9 competitiveness, the demand for skills, and the distribution of, and access to resources. The existing
10 digital divide, especially in developing countries, and the lack of appropriate governance of the digital
11 revolution can hamper the role that digitalisation could play in supporting the achievement of stringent
12 mitigation targets. At present, the understanding of both the direct and indirect impacts of digitalisation
13 on energy use, carbon emissions and potential mitigation is limited (medium confidence).
14 The digital transformation is a megatrend that is fundamentally changing all economies and societies,
15 albeit in very different ways depending on the level of development of a given country and on the nature
16 of its economic system. Digital technologies have significant potential to contribute to decarbonisation
17 due to their ability to increase energy and material efficiency, make transport and building systems less
18 wasteful, and improve the access to services for consumers and citizens. Yet, if left unmanaged, the
19 digital transformation will probably increase energy demand, exacerbate inequities and the
20 concentration of power, leaving developing economies with less access to digital technologies behind,
21 raise ethical issues, reduce labour demand and compromise citizens’ welfare. Appropriate governance
22 of the digital transformation can ensure that digitalisation works as an enabler, rather than as a barrier
23 and further strain in decarbonisation pathways. Governance can ensure that digitalisation not only
24 reduces GHG emissions intensity but also contributes to reducing absolute GHG emission, constraining
25 run-away consumption. {Cross-Chapter Box 11 in Chapter 16, 16.2}
26 Digital technologies have the potential to reduce energy demand in all end-use sectors through steep
27 improvements in energy efficiency. This includes material input savings and increased coordination as
28 they allow the use of fewer inputs to perform a given task. Smart appliances and energy management,
29 supported by choice architectures, economic incentives and social norms, effectively reduce energy
30 demand and associated GHG emissions by 5-10% while maintaining equal service levels. Data centres
31 can also play a role in energy system management, for example by waste heat utilisation where district
32 heat systems are close by; temporal and spatial scheduling of electricity demand can provide about 6%
33 of the total potential demand response. {5.5, Cross-Chapter Box 11 Table 1 in Chapter 16}
34 Digital technologies, analytics and connectivity consume large amounts of energy implying higher
35 direct energy demand and related carbon emissions. Global energy demand from digital appliances
36 reached 7.14 EJ in 2018. The demand for computing services increased by 550% between 2010 and
37 2018 and is now estimated at 1% of global electricity consumption. Due to efficiency improvements,
38 the associated energy demand increased only modestly, by about 6% from 2000 to 2018. {Box 9.5}
39 System-wide effects endanger energy and GHG emission savings. Rising demand can diminish energy
40 savings, and also produce run-away effects associated with additional consumption and GHG emissions
41 if left unregulated. Savings are varied in smart and shared mobility systems, as ride hailing increases
42 GHG emissions due to deadheading, whereas shared pooled mobility and shared cycling reduce GHG
43 emissions, as occupancy levels and/or weight per person kilometre transported improve. Systemic
44 effects have wider boundaries of analysis and are more difficult to quantify and investigate but are
45 nonetheless very relevant. Systemic effects tend to have negative impacts, but policies and adequate
46 infrastructures and choice architectures can help manage and contain these. {5.3, 5.4, 5.6}
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1 END BOX TS.14 HERE
2 TS. 7 Mitigation in the context of sustainable development
3 Accelerating climate mitigation in the context of sustainable development involves not only expediting
4 the pace of change but also addressing the underlying drivers of vulnerability and emissions.
5 Addressing these drivers can enable diverse communities, sectors, stakeholders, regions and cultures to
6 participate in just, equitable and inclusive processes that improve the health and well-being of people
7 and the planet. Looking at climate change from a justice perspective also means placing the emphasis
8 on: i) the protection of vulnerable populations from the impacts of climate change, ii) mitigating
9 the effects of low-carbon transformations, and iii) ensuring an equitable decarbonised world (high
10 confidence). {17.1}
11 The SDG framework25 can serve as a template to evaluate the long-term implications of mitigation
12 on sustainable development and vice versa (high confidence). Understanding the co-benefits and
13 trade-offs associated with mitigation is key to understanding how societies prioritise among the
14 various sectoral policy options (medium confidence). Areas with anticipated trade-offs include food
15 and biodiversity, energy affordability/access, and mineral resource extraction. Areas with anticipated
16 co-benefits include health, especially regarding air pollution, clean energy access and water availability.
17 The possible implementation of the different sectoral mitigation options therefore depends on
18 how societies prioritise mitigation versus other products and services: not least, how societies prioritise
19 food, material well-being, nature conservation and biodiversity protection, as well as considerations
20 such as their future dependence on CDR. Figure TS.29 summarises the assessment of where key
21 synergies and trade-offs exist between mitigation options and the SDGs. (Figure TS.29, Figure TS.31,
22 Table TS.7) {12.3, 12.4, 12.5, 12.6.1, Figure 3.39, Figure 17.1}
23 The beneficial and adverse impacts of deploying climate-change mitigation and adaptation
24 responses are highly context-specific and scale-dependent. There are synergies and trade-offs
25 between adaptation and mitigation as well as synergies and trade-offs with sustainable
26 development (high confidence). Strong links also exists between sustainable development,
27 vulnerability and climate risks, as limited economic, social and institutional resources often result in
28 low adaptive capacities and high vulnerability, especially in developing countries. Resource limitations
29 in these countries can similarly weaken the capacity for climate mitigation and adaptation. The move
30 towards climate-resilient societies requires transformational or deep systemic change. This has
31 important implications for countries’ sustainable development pathways (medium evidence, high
32 agreement). (Box TS.3, Figure TS.29) {4.5, Figure 4.9, 17.3.3}
33
FOOTNOTE 25 The 17 SDGs are at the heart of the UN 2030 Agenda for Sustainable Development, adopted by
all United Nations Member States in 2015.
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1 Figure TS.29: Mitigation options have synergies with many Sustainable Development Goals, but there are
2 trade-offs associated with some options especially when implemented at scale. The synergies and trade-
3 offs vary widely and depend on the context
4
5 Figure TS.29 legend: Figure TS.29 presents a summary of the chapter-level qualitative assessment of the
6 synergies and trade-offs for selected mitigation options. Overlaps may exist in the mitigation options assessed
7 and presented by sector and system, and interlinkages with the SDGs might differ depending on the application
8 of that option by sector. Interactions of mitigation options with the SDGs are context-specific and dependent on
9 the scale of implementation. For some mitigation options, these scaling and context-specific issues imply that
10 there are both synergies and trade-offs in relation to specific SDGs. The SDGs are displayed as coloured
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1 squares. They indicate whether a synergy, trade-off or both synergies and trade-offs exist between the SDG and
2 the mitigation option. Confidence levels are indicated through the solidity of the squares. A solid square
3 indicates high confidence, a partially filled square indicates medium confidence, and an outlined square
4 indicates low confidence. The final column in the figure provides a line of sight to the chapters that provide
5 details on context-specificity and scale of implementation. {6.3, 6.4, 6.7, 7.3, 7.4, 7.5, 7.6, 8.2, 8.4, 8.6, 9.4, 9.5,
6 9.8, Table 9.5, 10.3, 10.4, 10.5, 10.6, 10.8, 11.5, Table 10.3, 17.3, Figure 17.1, Supplementary Material
7 Table 17.1, Annex II Part IV Section 12}
8
9 Many of the potential trade-offs between mitigation and other sustainable development outcomes
10 depend on policy design and can be compensated or avoided with additional policies and
11 investments, or through policies that integrate mitigation with other SDGs (high confidence).
12 Targeted SDG policies and investments, for example in the areas of healthy nutrition, sustainable
13 consumption and production, and international collaboration, can support climate change mitigation
14 policies and resolve or alleviate trade-offs. Trade-offs can also be addressed by complementary policies
15 and investments, as well as through the design of cross-sectoral policies integrating mitigation with the
16 SDGs, and in particular: good health and well-being (SDG 3), zero hunger and nutrition (SDG 2),
17 responsible consumption and production (SDG 12), reduced inequalities (SDG 10) and life on land
18 (SDG 15). (Figure TS.29, Figure TS.30) {3.7}
19 Decent living standards, which encompasses many SDG dimensions, are achievable at lower
20 energy use than previously thought (high confidence). Mitigation strategies that focus on lowering
21 demand for energy and land-based resources exhibit reduced trade-offs and negative consequences for
22 sustainable development relative to pathways involving either high emissions and climate impacts or
23 pathways with high consumption and emissions that are ultimately compensated by large quantities of
24 BECCS. Figure TS.30 illustrates how, in the case of pathways likely limiting warming to 1.5°C,
25 sustainable development policies can lead to overall benefits compared to mitigation policies alone.
26 (Figure TS.22, Figure TS.30) {3.7, 5.2}
27 The timing of mitigation actions and their effectiveness will have significant consequences for
28 broader sustainable development outcomes in the longer term (high confidence). Ambitious
29 mitigation can be considered a precondition for achieving the SDGs. {3.7}
30 Adopting coordinated cross-sectoral approaches to climate mitigation can target synergies and
31 minimise trade-offs, both between sectors and between sustainable development objectives (high
32 confidence). This requires integrated planning using multiple-objective-multiple-impact policy
33 frameworks. Strong inter-dependencies and cross-sectoral linkages create both opportunities for
34 synergies and need to address trade-offs related to mitigation options and technologies. This can only
35 be done if coordinated sectoral approaches to climate change mitigation policies are adopted that
36 mainstream these interactions and ensure local people are involved in the development of new products,
37 as well as production and consumption practices. For instance, there can be many synergies in urban
38 areas between mitigation policies and the SDGs but capturing these depends on the overall planning of
39 urban structures and on local integrated policies such as combining affordable housing and spatial
40 planning with walkable urban areas, green electrification and clean renewable energy (medium
41 confidence). Integrated planning and cross-sectoral alignment of climate change policies are also
42 particularly evident in developing countries’ NDCs under the Paris Agreement, where key priority
43 sectors such as agriculture and energy are closely aligned with the proposed mitigation and adaptation
44 actions and the SDGs. {12.6.2, Supplementary Material Table 17.1, 17.3.3}
45
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1
2 Figure TS.30: Impacts on SDGs of mitigation likely limiting warming to 1.5°C with narrow mitigation
3 policies vs broader sustainable development policies
4
5 Figure TS.30 legend: Left: benefits of mitigation from avoided impacts. Middle: sustainability co-benefits and
6 trade-offs of narrow mitigation policies (averaged over multiple models). Right: sustainability co-benefits and
7 trade-offs of mitigation policies integrating sustainable development goals. Scale: 0% means no change
8 compared to 3°C (left) or current policies (middle and right). Green values correspond to proportional
9 improvements, red values to proportional worsening. Note: only the left panel considers climate impacts on
10 sustainable development; the middle and right panels do not. “Res’ C&P” stands for Responsible Consumption
11 and Production (SDG 12). {Figure 3.39}
12
13 The feasibility of deploying response options is shaped by barriers and enabling conditions across
14 geophysical, environmental-ecological, technological, economic, socio-cultural, and institutional
15 dimensions (high confidence). Accelerating the deployment of response options depends on reducing
16 or removing barriers across these dimensions, as well on establishing and strengthening enabling
17 conditions. Feasibility is context-dependent, and also depends on the scale and the speed of
18 implementation. For example: the institutional, legal and administrative capacity to support deployment
19 varies across countries; the feasibility of options that involve large-scale land use changes is highly
20 context dependent; spatial planning has a higher potential in early stages of urban development; the
21 geophysical potential of geothermal is site specific; and cultural and local conditions may either inhibit
22 or enable demand-side responses. Figure TS.31 summarises the assessment of barriers and enablers for
23 a broad range of sector specific, and cross sectoral response options. (Box TS.15) {6.4, 7.4, 8.5, 9.10,
24 10.8, 12.3}
25
26
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1
2
3 Figure TS.31 Geophysical, environmental-ecological, technological, economic, socio-cultural and
4 institutional factors can enable or act as barriers to the deployment of response options
5 Figure TS.31 legend: chapter-level assessment for selected mitigation options. Overlaps may exist in the
6 mitigation options assessed and presented by sector and system, and feasibility might differ depending on the
7 demarcation of that option in each sector. Chapters 6, 8, 9, 10, and 12 assess mitigation response options across
8 six feasibility dimensions: geophysical, environmental-ecological, technological, economic, socio-cultural and
9 institutional. AFOLU (Ch7) and industry (Ch11) are not included because of the heterogeneity of options in
10 these sectors. For each dimension, a set of feasibility indicators was identified. Examples of indicators include
11 impacts on land use, air pollution, economic costs, technology scalability, public acceptance and political
12 acceptance (see Box TS.15, and Annex II Part IV Section 11 for a detailed explanation). An indicator could
13 refer to a barrier or an enabler to implementation, or could refer to both a barrier or an enabler, depending on the
14 context, speed, and scale of implementation. Dark blue bars indicate the extent of enablers to deployment within
15 each dimension. This is shown relative to the maximum number of possible enablers, as indicated by the light
16 blue shading. Dark orange bars indicate the extent of barriers to deployment within each dimension. This is
17 shown relative to the maximum number of possible barriers, as indicated by light orange shading. A light grey
18 dot indicates that there is limited or no evidence to assess the option. A dark grey dot indicates that one of the
19 feasibility indicators within that dimension is not relevant for the deployment of the option. The relevant
20 sections in the underlying chapters include references to the literature on which the assessment is based and
21 indicate whether the feasibility of an option varies depending on context (e.g., region), scale (e.g., small,
22 medium, full scale), speed (e.g., implementation in 2030 versus 2050) and warming level (e.g., 1.5°C versus
23 2°C). {6.4, 8.5, 9.10, 10.8, 12.3, Annex II Part IV Section 11}
24 Alternative mitigation pathways are also associated with different feasibility challenges (high
25 confidence). These challenges are multi-dimensional, context-dependent, malleable to policy and to
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1 technological and societal trends. They can also be reduced by putting in place appropriate enabling
2 conditions. Figure TS.32 highlights the dynamic and transient nature of feasibility risks. These risks are
3 transient and concentrated in the decades before mid-century. Figure TS.32 also illustrates how different
4 feasibility dimensions pose differentiated challenges: for example, institutional feasibility challenges
5 are shown as unprecedented for a high proportion of scenarios, in line with the qualitative literature,
6 but moving from 2030 to 2050 and 2100 these challenges decrease.
7 The feasibility challenges associated with mitigation pathways are predominantly institutional
8 and economic rather than technological and geophysical (medium confidence). The rapid pace of
9 technological development and deployment in mitigation scenarios is not incompatible with historical
10 records, but rather, institutional capacity is a key limiting factor for a successful transition. Emerging
11 economies appear to have highest feasibility challenges in the short- to medium- term. This suggests
12 a key role of policy and technology as enabling factors. (Figure TS.32) {3.8}
13 Pathways relying on a broad portfolio of mitigation strategies are more robust and resilient (high
14 confidence). Portfolios of technological solutions reduce the feasibility risks associated with the low
15 carbon transition. (Figure TS.31, Figure TS.32, Box TS.15) {3.8}
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1
2 Figure TS.32: The feasibility of mitigation scenarios
3
4 Figure TS.32 legend: Figure shows the proportion scenarios in the AR6 scenarios database – falling withing
5 the warming level classifications C1 and C3 (C1: below 1.5°C, no or limited overshoot; C3: likely below 2°C)
6 – that exceed threshold values in 2030, 2050 and 2100 for five dimensions of feasibility (See Box TS.5, Box
7 TS.15). The feasibility dimensions shown are: geophysical, technological, economic, socio-cultural and
8 institutional. The thresholds shown are: i) plausible – range of values based on past historical trends or other
9 peer reviewed assessments; ii) best case scenario – range of values assuming major political support or
10 technological breakthrough; iii) unprecedented – values going beyond those observed or reported in peer
11 reviewed assessments. Overlayed are the Illustrative Mitigation Pathways consistent with SSP2 (LD, SP, Ren:
12 C1 category; Neg, GS: C3 category). The positioning of the illustrative pathways is simply indicative of the
13 general trade-offs over time and across the feasibility dimensions it is not determined mathematically.
14 (Box TS.5) {3.8}
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1
2 START BOX TS.15 HERE
3 Box TS.15: A harmonised approach to assessing feasibility
4 The assessment of feasibility in this report aims to identify barriers and enablers to the deployment of
5 mitigation options and pathways. The assessment organises evidence to support policy decisions, and
6 decisions on actions, that would improve the feasibility of mitigation options and pathways by removing
7 relevant barriers and by strengthening enablers of change.
8 The feasibility of mitigation response options
9 Mitigation response options are assessed against six dimensions of feasibility. Each dimension
10 comprises a key set of indicators that can be evaluated by combining various strands of literature.
11 {Annex II Part IV Section 11, Table 6.1}
12 Box TS.15 Table.1: Feasibility dimensions and indicators to assess the barriers and enablers of
13 implementing mitigation options
14
Feasibility dimension Indicators
Geophysical feasibility Availability of required geophysical resources:
• Physical potential
• Geophysical resource availability
• Land use
Environmental-ecological Impacts on environment:
feasibility • Air pollution
• Toxic waste, ecotoxicity and eutrophication
• Water quantity and quality
• Biodiversity
Technological feasibility Extent to which the technology can be implemented at scale soon
• Simplicity
• Technology scalability
• Maturity and technology readiness
Economic feasibility Financial costs and economic effects
• Costs now, in 2030 and in the long term
• Employment effects and economic growth
Socio-cultural feasibility Public engagement and support, and social impacts:
• Public acceptance
• Effects on health and well-being
• Distributional effects
Institutional feasibility Institutional conditions that affect the implementation of the response
option
• Political acceptance
• Institutional capacity and governance, cross-sectoral coordination
• Legal and administrative capacity
15
16 The assessment – undertaken by the sectoral chapters in this report – evaluates to what extent each
17 indicator (listed in Box TS.15 Table.1) would be an enabler or barrier to implementation using a scoring
18 methodology (described in detail in Annex II Part IV Section 11). When appropriate, it is also indicated
19 whether the feasibility of an option varies across context, scale, time and temperature goal. The resulting
20 scores provide insight into the extent to which each feasibility dimension enables or inhibits the
21 deployment of the relevant option. It also provides insight into the nature of the effort needed to reduce
22 or remove barriers thereby improving the feasibility of individual options. {Annex II Part IV Section
23 11}
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1 The feasibility of mitigation scenarios
2 Scenarios provide internally consistent projections of emission reduction drivers and help contextualize
3 the scale of deployment and interactions of mitigation strategies. Recent research has proposed and
4 operationalised frameworks for the feasibility assessment of mitigation scenarios. In this report the
5 feasibility assessment of scenarios uses an approach that involves developing a set of multi-dimensional
6 metrics capturing the timing, disruptiveness and the scale of the transformative change within five
7 dimensions: geophysical, technological, economic, socio-cultural and institutional, as illustrated in
8 Box TS.15 Figure 1.
9 More than 20 indicators were chosen to represent feasibility dimensions that could be related to scenario
10 metrics. Thresholds of feasibility risks of different intensity were obtained through empirical analysis
11 of historical data and assessed literature. Details of indicators, thresholds, and how they were applied is
12 reported in Annex II Part IV Section 11. {3.8}
13
14 Box TS.15 Figure 1: Steps involved in evaluating the feasibility of scenarios {Figure 3.41}
15 Note: In this approach the environmental-ecological dimension is captured through different scenarios’
16 categories.
17 END BOX TS.15 HERE
18
19 A wide range of factors have been found to enable sustainability transitions, ranging from
20 technological innovations to shifts in markets, and from policies and governance arrangements
21 to shifts in belief systems and market forces (high confidence). Many of these factors have come
22 together in a co-evolutionary process that has unfolded globally, internationally and locally over several
23 decades (low evidence, high agreement). Those same conditions that may serve to impede the transition
24 (i.e., organisational structure, behaviour, technological lock-in) can also ‘flip’ to enable both the
25 transition and the framing of sustainable development policies to create a stronger basis for policy
26 support (high confidence). It is important to note that strong shocks to these systems, including
27 accelerating climate change impacts, economic crises and political changes, may provide crucial
28 openings for accelerated transitions to sustainable systems. For example, re-building more sustainably
29 after an extreme event, or renewed public debate about the drivers of social and economic vulnerability
30 to multiple stressors (medium confidence). {17.4}
31 While transition pathways will vary across countries it is anticipated that they will be challenging
32 in many contexts (high confidence). Climate change is the result of decades of unsustainable
33 production and consumption patterns, as well as governance arrangements and political economic
34 institutions that lock in resource-intensive development patterns (high confidence). Resource shortages,
35 social divisions, inequitable distributions of wealth, poor infrastructure and limited access to advanced
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1 technologies and skilled human resources can constrain the options and capacity of developing
2 countries to achieve sustainable and just transitions (medium evidence, high agreement) {17.1.1}.
3 Reframing development objectives and shifting development pathways towards sustainability can help
4 transform these patterns and practices, allowing space to transform unsustainable systems (medium
5 evidence, high agreement). {1.6, Cross-Chapter Box 5 in Chapter 4, 17.1, 17.3}
6 The landscape of transitions to sustainable development is changing rapidly, with multiple
7 transitions already underway. This creates the room to manage these transitions in ways that
8 prioritise the needs of workers in vulnerable sectors (e.g., land, energy) to secure their jobs and
9 maintain secure and healthy lifestyles (medium evidence, high agreement). {17.3.2}
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11 Actions aligning sustainable development, climate mitigation and partnerships can support
12 transitions. Strengthening different stakeholders’ “response capacities” to mitigate and adapt to
13 a changing climate will be critical for a sustainable transition (high confidence). {17.1}
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15 Accelerating the transition to sustainability will be enabled by explicit consideration being given
16 to the principles of justice, equality and fairness (high confidence). {5.2, 5.4, 5.6, 13.2, 13.6, 13.8,
17 13.9,17.4}
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