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IPCC AR6 SYRSYNTHESIS REPORTOF THE IPCC SIXTH ASSESSMENT REPORT (AR6)Longer Report
Core Writing Team: Hoesung Lee (Chair), Katherine Calvin (USA), Dipak Dasgupta (India/USA), Gerhard
Krinner (France/Germany), Aditi Mukherji (India), Peter Thorne (Ireland/United Kingdom), Christopher
Trisos (South Africa), José Romero (Switzerland), Paulina Aldunce (Chile), Ko Barrett (USA), Gabriel Blanco(Argentina), William W. L. Cheung (Canada), Sarah L. Connors (France/United Kingdom), Fatima Denton(The Gambia), Aïda Diongue-Niang (Senegal), David Dodman (Jamaica/United Kingdom/Netherlands),
Matthias Garschagen (Germany), Oliver Geden (Germany), Bronwyn Hayward (New Zealand), Christopher
Jones (United Kingdom), Frank Jotzo (Australia), Thelma Krug (Brazil), Rodel Lasco (Philippines), June-Yi
Lee (Republic of Korea), Valérie Masson-Delmotte (France), Malte Meinshausen (Australia/Germany), Katja
Mintenbeck (Germany), Abdalah Mokssit (Morocco), Friederike E. L. Otto (United Kingdom/Germany),
Minal Pathak (India), Anna Pirani (Italy), Elvira Poloczanska (UK/Australia), Hans-Otto Pörtner (Germany),Aromar Revi (India), Debra C. Roberts (South Africa), Joyashree Roy (India/Thailand), Alex C. Ruane (USA),
Jim Skea (United Kingdom), Priyadarshi R. Shukla (India), Raphael Slade (United Kingdom), Aimée Slangen(The Netherlands), Youba Sokona (Mali), Anna A. Sörensson (Argentina), Melinda Tignor (USA/Germany),
Detlef van Vuuren (The Netherlands), Yi-Ming Wei (China), Harald Winkler (South Africa), Panmao Zhai(China), Zinta Zommers (Latvia)
Extended Writing Team: Jean-Charles Hourcade (France), Francis X. Johnson (Thailand/Sweden), Shonali
Pachauri (Austria/India), Nicholas P. Simpson (South Africa/Zimbabwe), Chandni Singh (India), Adelle
Thomas (Bahamas), Edmond Totin (Benin)
Contributing Authors: Andrés Alegría (Germany/Honduras), Kyle Armour (USA), Birgit Bednar-Friedl(Austria), Kornelis Blok (The Netherlands) Guéladio Cissé (Switzerland/Mauritania/France), Frank Dentener(EU/Netherlands), Siri Eriksen (Norway), Erich Fischer (Switzerland), Gregory Garner (USA), Céline
Guivarch (France), Marjolijn Haasnoot (The Netherlands), Gerrit Hansen (Germany), Matthias Hauser(Switzerland), Ed Hawkins (UK), Tim Hermans (The Netherlands), Robert Kopp (USA), Noëmie LeprinceRinguet (France), Debora Ley (Mexico/Guatemala), Jared Lewis (Australia/New Zealand), Chloé Ludden(Germany/France), Zebedee Nicholls (Australia), Leila Niamir (Iran/The Netherlands/Austria), Shreya Some(India/Thailand), Sophie Szopa (France), Blair Trewin (Australia), Kaj-Ivar van der Wijst (The Netherlands),Gundula Winter (The Netherlands/Germany), Maximilian Witting (Germany)
Review Editors: Paola Arias (Colombia), Mercedes Bustamante (Brazil), Ismail Elgizouli (Sudan), Gregory
Flato (Canada), Mark Howden (Australia), Carlos Méndez (Venezuela), Joy Pereira (Malaysia), Ramón PichsMadruga (Cuba), Steven K Rose (USA), Yamina Saheb (Algeria/France), Roberto Sánchez (Mexico), Diana
Ürge-Vorsatz (Hungary), Cunde Xiao (China), Noureddine Yassaa (Algeria)
Scientific Steering Committee: Hoesung Lee (Chair, IPCC), Amjad Abdulla (Maldives), Edvin Aldrian(Indonesia), Ko Barrett (United States of America), Eduardo Calvo (Peru), Carlo Carraro (Italy), Fatima
Driouech (Morocco), Andreas Fischlin (Switzerland), Jan Fuglestvedt (Norway), Diriba Korecha Dadi(Ethiopia), Thelma Krug (Brazil), Nagmeldin G.E. Mahmoud (Sudan), Valérie Masson-Delmotte (France),Carlos Méndez (Venezuela), Joy Jacqueline Pereira (Malaysia), Ramón Pichs-Madruga (Cuba), Hans-OttoPörtner (Germany), Andy Reisinger (New Zealand), Debra Roberts (South Africa), Sergey Semenov (RussianFederation), Priyadarshi Shukla (India), Jim Skea (United Kingdom), Youba Sokona (Mali), Kiyoto Tanabe(Japan), Muhammad IrfanTariq (Pakistan), Diana Ürge-Vorsatz (Hungary), Carolina Vera (Argentina), PiusYanda (United Republic of Tanzania), Noureddine Yassaa (Algeria), Taha M. Zatari (Saudi Arabia), PanmaoZhai (China)
Visual Conception and Information Design: Arlene Birt (USA), Meeyoung Ha (Republic of Korea)

Notes: SFs Compiled Version
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Table of Contents
Section 1: Introduction

4Section 2: Current Status and Trends

6

2.1

Observed Changes, Impacts and Attribution

6

2.1.1

Observed Warming and its Causes

6

2.1.2

Observed Climate System Changes and Impacts to Date

112.2

Responses Undertaken to Date

18

2.2.1

Global Policy Setting

18

2.2.2

Mitigation Actions to Date

19

2.2.3

Adaptation Actions to Date

21

2.3

Current Mitigation and Adaptation Actions and Policies are not Sufficient

23

2.3.1
The Gap Between Mitigation Policies, Pledges and Pathways that Limit Warming to 1.5 orBelow 2°C
23
Cross-Section Box.1: Understanding Net Zero CO2 and Net Zero GHG Emissions

26

2.3.2

Adaptation Gaps and Barriers

27

2.3.3

Lack of Finance as a Barrier to Climate Action

28

Cross-Section Box.2: Scenarios, Global Warming Levels, and Risks

29

Section 3: Long-Term Climate and Development Futures
3.1

33

Long-Term Climate Change, Impacts and Related Risks

33

3.1.1Long-term Climate Change

33

3.1.2

Impacts and Related Risks

36

3.1.3

The Likelihood and Risks of Abrupt and Irreversible Change

42

3.2

Long-term Adaptation Options and Limits

43

3.3

Mitigation Pathways

46

3.3.1

Remaining Carbon Budgets

46

3.3.2

Net Zero Emissions: Timing and Implications

50

3.3.3

Sectoral Contributions to Mitigation

51

3.3.4

Overshoot Pathways: Increased Risks and Other Implications

53

3.4

Long-Term Interactions Between Adaptation, Mitigation and Sustainable Development

53

3.4.1

Synergies and trade-offs, costs and benefits

53

3.4.2

Advancing Integrated Climate Action for Sustainable Development

55

Section 4: Near-Term Responses in a Changing Climate

56

4.1

The Timing and Urgency of Climate Action

56

4.2

Benefits of Strengthening Near-Term Action

59

4.3

Near-Term Risks

62

4.4

Equity and Inclusion in Climate Change Action

66

4.5

Near-Term Mitigation and Adaptation Actions

68

4.5.1

Energy Systems

70

4.5.2

Industry

71

4.5.3

Cities, Settlements and Infrastructure

72

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4.5.4

Land, Ocean, Food, and Water

73

4.5.5

Health and Nutrition

744.5.6

Society, Livelihoods, and Economies

74

4.6

Co-Benefits of Adaptation and Mitigation for Sustainable Development Goals

75

4.7

Governance and Policy for Near-Term Climate Change Action

78

4.8

Strengthening the Response: Finance, International Cooperation and Technology

80

4.8.1

Finance for Mitigation and Adaptation Actions

80

4.8.2

International Cooperation and Coordination

82

4.8.3

Technology Innovation, Adoption, Diffusion and Transfer

83

Integration of Near-Term Actions Across Sectors and Systems

84

4.9

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IPCC AR6 SYRSection 4: Near-Term Responses in a Changing Climate
1.1

The Timing and Urgency of Climate Action

Deep, rapid and sustained mitigation and accelerated implementation of adaptation reduces the risksof climate change for humans and ecosystems. In modelled pathways that limit warming to 1.5°C(>50%) with no or limited overshoot and in those that limit warming to 2°C (>67%) and assume
immediate action, global GHG emissions are projected to peak in the early 2020s followed by rapidand deep reductions. As adaptation options often have long implementation times, accelerated
implementation of adaptation, particularly in this decade, is important to close adaptation gaps. (highconfidence)
The magnitude and rate of climate change and associated risks depend strongly on near-term mitigation
and adaptation actions (very high confidence). Global warming is more likely than not to reach 1.5°C
between 2021 and 2040 even under the very low GHG emission scenarios (SSP1-1.9), and likely or very likely
to exceed 1.5°C under higher emissions scenarios84. Many adaptation options have medium or high feasibilityup to 1.5°C (medium to high confidence, depending on option), but hard limits to adaptation have already beenreached in some ecosystems and the effectiveness of adaptation to reduce climate risk will decrease withincreasing warming (high confidence). Societal choices and actions implemented in this decade determine theextent to which medium- and long-term pathways will deliver higher or lower climate resilient development(high confidence). Climate resilient development prospects are increasingly limited if current greenhouse gas
emissions do not rapidly decline, especially if 1.5°C global warming is exceeded in the near-term (highconfidence). Without urgent, effective and equitable adaptation and mitigation actions, climate change
increasingly threatens the health and livelihoods of people around the globe, ecosystem health, and biodiversity,with severe adverse consequences for current and future generations (high confidence). {WGI SPM B.1.3,
WGI SPM B.5.1, WGI SPM B.5.2; WGII SPM A, WGII SPM B.4, WGII SPM C.2, WGII SPM C.3.3, WGII
Figure SPM.4, WGII SPM D.1, WGII SPM D.5, WGIII SPM D.1.1 SR1.5 SPM D.2.2}. (CrossSection Box.2, Figure 2.1, Figure 2.3)
In modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot and in thosethat limit warming to 2°C (>67%), assuming immediate actions, global GHG emissions are projected topeak in the early 2020s followed by rapid and deep GHG emissions reductions (high confidence) 85. In
pathways that limit warming to 1.5°C (>50%) with no or limited overshoot, net global GHG emissions areprojected to fall by 43% [34–60%]86 below 2019 levels by 2030,60% [49–77%] by 2035, 69% [58-90%] by2040 and 84% [73-98%] (high confidence) (Section 2.3.1, Table 2.2, Figure 2.5, Table 3.1)87. Global modelled
pathways that limit warming to 2°C (>67%) have reductions in GHG emissions below 2019 levels of 21% [1–42]% by 2030, 35% [22–55%] by 2035, 46% [34-63%] by 2040 and 64% [53-77%] by 2050 88(highconfidence). Global GHG emissions associated with NDCs announced prior to COP26 would make it likelythat warming would exceed 1.5°C (high confidence) and limiting warming to 2°C (>67%) would then imply arapid acceleration of emission reductions during 2030–2050, around 70% faster than in pathways whereimmediate action is taken to limit warming to 2°C (>67%) (medium confidence) (Section 2.3.1) Continued
investments in unabated high-emitting infrastructure89 and limited development and deployment of lowemitting alternatives prior to 2030 would act as barriers to this acceleration and increase feasibility risks (highconfidence). {WGIII SPM B.6.3, WGIII Chapter 3.5.2, WGIII SPM B.6, WGIII SPM B.6., WGIII SPM C.1,WGIII SPM C1.1, Table SPM.2} (Cross-Section Box.2)
84In the near term (2021–2040), the 1.5°C global warming level is very likely to be exceeded under the very high GHG emissionsscenario (SSP5-8.5), likely to be exceeded under the intermediate and high GHG emissions scenarios (SSP2-4.5, SSP3-7.0), more likely
than not to be exceeded under the low GHG emissions scenario (SSP1-2.6) and more likely than not to be reached under the very low
GHG emissions scenario (SSP1-1.9). The best estimates [and very likely ranges] of global warming for the different scenarios in thenear-term are: 1.5°C [1.2°C–1.7°C] (SSP1-1.9); 1.5°C [1.2°C–1.8°C] (SSP1-2.6); 1.5°C [1.2°C–1.8°C] (SSP2-4.5); 1.5°C [1.2°C–1.8°C] (SSP3-7.0); and 1.6°C [1.3°C–1.9°C] (SSP5-8.5). {WGI SPM B.1.3, WGI Table SPM.1} (Cross-Section Box.2)
85 Values in parentheses indicate the likelihood of limiting warming to the level specified (see Cross-Section Box.2).
86 Median and very likely range [5th to 95th percentile] {WGIII SPM footnote 30}.
87 These numbers for CO2 are 48% [36-69] in 2030, 65% [50-96%] in 2035, 80% [61-109%] in 2040 and 99 [79-119%] in 2050.
88 These numbers for CO2 are 22% [1-44] in 2030, 37% [21-59%] in 2035, 51% [36-70%] in 2040 and 73 [55-90%] in 2050
89 In this context, ‘unabated fossil fuels’ refers to fossil fuels produced and used without interventions that substantially reduce theamount of GHG emitted throughout the life cycle; for example, capturing 90% or more CO2 from power plants, or 50–80% of fugitive
methane emissions from energy supply {WGIII SPM footnote 54}.
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All global modelled pathways that limit warming to 2°C (>67%) or lower by 2100 involve reductions inboth net CO2 emissions and non-CO2 emissions (see Figure 3.6) (high confidence). For example, inpathways that limit warming to 1.5°C (>50%) with no or limited overshoot, global CH4 (methane) emissions
are reduced by 34% [21–57%] below 2019 levels by 2030 and by 44% [31–63%] in 2040 (high confidence).
Global CH4 emissions are reduced by 24% [9–53%] below 2019 levels by 2030 and by 37% [20–60%] in 2040
in modelled pathways that limit warming to 2°C with action starting in 2020 (>67%) (high confidence).
{WGIII SPM C1.2, WGIII Table SPM.2, WGIII Chapter 3.3; SR1.5 SPM C.1, SR1.5 SPM C.1.2} (CrossSection Box.2)
All global modelled pathways that limit warming to 2°C (>67%) or lower by 2100 involve GHG emission
reductions in all sectors (high confidence). The contributions of different sectors vary across modelled
mitigation pathways. In most global modelled mitigation pathways, emissions from land-use, land-use change
and forestry, via reforestation and reduced deforestation, and from the energy supply sector reach net zero CO2emissions earlier than the buildings, industry and transport sectors (Figure 4.1). Strategies can rely on
combinations of different options (Figure 4.1, Section 4.5), but doing less in one sector needs to becompensated by further reductions in other sectors if warming is to be limited. (high confidence) {WGIII SPM
C.3, WGIII SPM C.3.1, WGIII SPM 3.2, WGIII SPM C.3.3} (Cross-Section Box.2)
Without rapid, deep and sustained mitigation and accelerated adaptation actions, losses and damages
will continue to increase, including projected adverse impacts in Africa, LDCs, SIDS, Central and SouthAmerica90, Asia and the Arctic, and will disproportionately affect the most vulnerable populations (highconfidence). {WGII SPM C.3.5; WGII SPM B.2.4; WGII Global to Regional Atlas Annex A1.15, A1.27;
WGII 12.2; WGII 10. Box 10.6; WGII TS D.7.5; WGII CCB6 ES; SR1.5 SPM B.5.3; SR 1.5 SPM B.5.7;
SRCCL A.5.6} (Figure 3.2; Figure 3.3)

[START FIGURE 4.1 HERE]

90 The southern part of Mexico is included in the climatic subregion South Central America (SCA) for WGI. Mexico is assessed as partof North America for WGII. The climate change literature for the SCA region occasionally includes Mexico, and in those cases WGII
assessment makes reference to Latin America. Mexico is considered part of Latin America and the Caribbean for WGIII. {WGII 12.1.1,
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Figure 4.1: Sectoral emissions in pathways that limit warming to 1.5°C. Panel (a) shows sectoral CO2 and non-CO2emissions in global modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot. The horizontal
lines illustrate halving 2015 emissions (base year of the pathways) (dashed) and reaching net-zero emissions (solid line).
The range shows the 5–95th percentile of the emissions across the pathways. The timing strongly differs by sector, with
the CO2 emissions from the electricity/fossil fuel industries sector and land-use change generally reaching net zero earlier.
Non-CO2 emissions from agriculture are also substantially reduced compared to pathways without climate policy but do
not typically reach zero. Panel (b) Although all pathways include strongly reduced emissions, there are different pathways
as indicated by the illustrative mitigation pathways used in IPCC WGIII. The pathways emphasise routes consistent withlimiting warming to 1.5°C with a high reliance on net negative emissions (IMP-Neg), high resource efficiency (IMP-LD),a focus on sustainable development (IMP-SP) or renewables (IMP-Ren) and consistent with 2°C
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based on a less rapid introduction of mitigation measures followed by a subsequent gradual strengthening (IMP-GS).
Positive (solid filled bars) and negative emissions (hatched bars) for different illustrative mitigation pathways arecompared to GHG emissions from the year 2019. The category “energy supply (including electricity)” includes bioenergywith carbon capture and storage and direct air carbon capture and storage. {WGIII Box TS.5, 3.3, 3.4, 6.6, 10.3, 11.3}(Cross-Section Box 2)[END FIGURE 4.1 HERE]

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