Intergovernmental Panel on Climate Change IPCC - Revision history

Editor at 16:35, 5 April 2022

2022-04-05T16:35:34Z

← Older revision		Revision as of 16:35, 5 April 2022
Line 72:		Line 72:
	Increasing diversity of analytic frameworks from multiple disciplines including social sciences. This report identifies multiple analytic frameworks to assess the drivers of, barriers to and options for, mitigation action. These include: economic efficiency including the benefits of avoided impacts; ethics and equity; interlinked technological and social transition processes; and socio-political frameworks, including institutions and governance. These help to identify risks and opportunities for action including co-benefits and just and equitable transitions at local, national and global scales.		Increasing diversity of analytic frameworks from multiple disciplines including social sciences. This report identifies multiple analytic frameworks to assess the drivers of, barriers to and options for, mitigation action. These include: economic efficiency including the benefits of avoided impacts; ethics and equity; interlinked technological and social transition processes; and socio-political frameworks, including institutions and governance. These help to identify risks and opportunities for action including co-benefits and just and equitable transitions at local, national and global scales.

−	== B. Recent developments and current trends ==	+	== B Recent developments and current trends ==

	B.1 Cumulative net CO2 emissions have risen since 1850. Average annual GHG emissions during 2010-2019 were higher than in any previous decade, but the rate of growth between 2010 and 2019 was lower than that between 2000 and 2009.		B.1 Cumulative net CO2 emissions have risen since 1850. Average annual GHG emissions during 2010-2019 were higher than in any previous decade, but the rate of growth between 2010 and 2019 was lower than that between 2000 and 2009.
Line 88:		Line 88:
	B.7 Projected cumulative future CO2 emissions over the lifetime of existing and currently planned fossil fuel infrastructure without additional abatement exceed the total cumulative net CO2 emissions in pathways that limit warming to 1.5°C (>50%) with no or limited overshoot. Approximately equal to total cumulative net CO2 in pathways limiting to 2°C (>67%).		B.7 Projected cumulative future CO2 emissions over the lifetime of existing and currently planned fossil fuel infrastructure without additional abatement exceed the total cumulative net CO2 emissions in pathways that limit warming to 1.5°C (>50%) with no or limited overshoot. Approximately equal to total cumulative net CO2 in pathways limiting to 2°C (>67%).

−	== C. System transformations to limit global warming ==	+	== C System transformations to limit global warming ==

	C.1 Global GHG emissions projected to peak between 2020 and at the latest before 2025 in pathways that limit warming to 1.5°C (>50%) limited overshoot and in those that limit warming to 2°C (>67%) assume immediate action. In both, rapid and deep GHG emissions reductions follow throughout 2030, 2040 and 2050. Without strengthening of post 2020 policies, GHG emissions are projected to rise beyond 2025, leading to a median global warming of 3.2 [2.2 to 3.5] °C by 2100.		C.1 Global GHG emissions projected to peak between 2020 and at the latest before 2025 in pathways that limit warming to 1.5°C (>50%) limited overshoot and in those that limit warming to 2°C (>67%) assume immediate action. In both, rapid and deep GHG emissions reductions follow throughout 2030, 2040 and 2050. Without strengthening of post 2020 policies, GHG emissions are projected to rise beyond 2025, leading to a median global warming of 3.2 [2.2 to 3.5] °C by 2100.
Line 114:		Line 114:
	C.12 Mitigation options costing USD100 tCO2-eq-1 or less could reduce global GHG emissions by at least half the 2019 level by 2030. Global GDP continues to grow in modelled pathways but, without accounting for the economic benefits of mitigation action from avoided damages from climate change nor from reduced adaptation costs, it is a few percent lower in 2050 compared to pathways without mitigation beyond current policies. The global economic benefit of limiting warming to 2°C is reported to exceed the cost of mitigation in most of the assessed literature.		C.12 Mitigation options costing USD100 tCO2-eq-1 or less could reduce global GHG emissions by at least half the 2019 level by 2030. Global GDP continues to grow in modelled pathways but, without accounting for the economic benefits of mitigation action from avoided damages from climate change nor from reduced adaptation costs, it is a few percent lower in 2050 compared to pathways without mitigation beyond current policies. The global economic benefit of limiting warming to 2°C is reported to exceed the cost of mitigation in most of the assessed literature.

−	== D. Linkages between mitigation, adaptation, and sustainable development ==	+	== D Linkages between mitigation, adaptation, and sustainable development ==

	D.1 Accelerated and equitable climate action in mitigating, and adapting to, climate change impacts is critical to sustainable development. Climate change actions can also result in trade-offs. The trade-offs of individual options could be managed through policy design. The Sustainable Development Goals (SDGs) adopted under the UN 2030 Agenda for Sustainable Development can be used as a basis for evaluating climate action in the context of sustainable development.		D.1 Accelerated and equitable climate action in mitigating, and adapting to, climate change impacts is critical to sustainable development. Climate change actions can also result in trade-offs. The trade-offs of individual options could be managed through policy design. The Sustainable Development Goals (SDGs) adopted under the UN 2030 Agenda for Sustainable Development can be used as a basis for evaluating climate action in the context of sustainable development.

Editor at 16:33, 5 April 2022

2022-04-05T16:33:18Z

← Older revision		Revision as of 16:33, 5 April 2022
Line 36:		Line 36:
	Since AR5, estimates of remaining carbon budgets have been improved by a new methodology first presented in SR1.5, updated evidence, and the integration of results from multiple lines of evidence. A comprehensive range of possible future air pollution controls in scenarios is used to consistently assess the effects of various assumptions on projections of climate and air pollution. A novel development is the ability to ascertain when climate responses to emissions reductions would become discernible above natural climate variability, including internal variability and responses to natural drivers.		Since AR5, estimates of remaining carbon budgets have been improved by a new methodology first presented in SR1.5, updated evidence, and the integration of results from multiple lines of evidence. A comprehensive range of possible future air pollution controls in scenarios is used to consistently assess the effects of various assumptions on projections of climate and air pollution. A novel development is the ability to ascertain when climate responses to emissions reductions would become discernible above natural climate variability, including internal variability and responses to natural drivers.

−	= [~~http~~:~~//www.ipcc.ch/report/ar5/wg2/~~ Climate Change 2022: Impacts, Adaptation and Vulnerability] =	+	= [[Climate_change_2022:_impacts,_adaptation_and_vulnerability_IPCC_report\|Climate Change 2022: Impacts, Adaptation and Vulnerability]] =

	== A Introduction ==		== A Introduction ==
Line 58:		Line 58:
	Climate-resilient development integrates adaptation measures and their enabling conditions (Section C) with mitigation to advance sustainable development for all. Climate resilient development involves questions of equity and system transitions in land, ocean and ecosystems; urban and infrastructure; energy; industry; and society and includes adaptations for human, ecosystem and planetary health. Pursuing climate resilient development focuses on both where people and ecosystems are co-located as well as the protection and maintenance of ecosystem function at the planetary scale. Pathways for advancing climate resilient development are development trajectories that successfully integrate mitigation and adaptation actions to advance sustainable development. Climate resilient development pathways may be temporarily coincident with any RCP and SSP scenario used throughout AR6, but do not follow any particular scenario in all places and over all time."		Climate-resilient development integrates adaptation measures and their enabling conditions (Section C) with mitigation to advance sustainable development for all. Climate resilient development involves questions of equity and system transitions in land, ocean and ecosystems; urban and infrastructure; energy; industry; and society and includes adaptations for human, ecosystem and planetary health. Pursuing climate resilient development focuses on both where people and ecosystems are co-located as well as the protection and maintenance of ecosystem function at the planetary scale. Pathways for advancing climate resilient development are development trajectories that successfully integrate mitigation and adaptation actions to advance sustainable development. Climate resilient development pathways may be temporarily coincident with any RCP and SSP scenario used throughout AR6, but do not follow any particular scenario in all places and over all time."

−	= [~~http~~:~~//www.ipcc.ch/report/ar5/wg3/~~ Climate Change 2022: Mitigation of Climate Change] =	+	= [[Climate_change_2022:_mitigation_of_climate_change_IPCC_report\|Climate Change 2022: Mitigation of Climate Change]] =

	== A Introduction and framing ==		== A Introduction and framing ==
Line 136:		Line 136:
	E.6 International cooperation is a critical enabler for achieving ambitious climate change mitigation goals. The UNFCCC, Kyoto Protocol, and Paris Agreement are supporting rising levels of national ambition and encouraging development and implementation of climate policies, although gaps remain. Partnerships, agreements, institutions and initiatives operating at the sub- global and sectoral levels and engaging multiple actors are emerging, with mixed levels of effectiveness.		E.6 International cooperation is a critical enabler for achieving ambitious climate change mitigation goals. The UNFCCC, Kyoto Protocol, and Paris Agreement are supporting rising levels of national ambition and encouraging development and implementation of climate policies, although gaps remain. Partnerships, agreements, institutions and initiatives operating at the sub- global and sectoral levels and engaging multiple actors are emerging, with mixed levels of effectiveness.

−	~~Proposals for mitigation include:~~	+	= 2018 synthesis report, due to be updated in October 2022 =
−		+
−	* Carbon dioxide capture and storage (CCS).	+
−	* Widespread afforestation.	+
−	* Bio-energy with carbon capture and storage (BECCS).	+
−	* Large-scale changes in the energy supply sector, ~~including devaluation of fossil fuel assets and reduction of revenues for fossil fuel exporters.~~	+
−	* Efficiency enhancements and behavioural changes in order to ~~reduce energy demand.~~	+
−	* The use of nuclear energy, although it acknowledges that there are barriers to adoption and that nuclear generation is in ~~fact decreasing.~~	+
−	* Replacing coal-fired power plants with natural gas combined-cycle power plants or combined heat and power plants.	+
−	* Adoption of renewable energy generation.	+
−	* Adoption of low-carbon transport.	+
−	* Low-energy urban design.	+
−		+
−	In relation to the built environment, it points out that in 2010, the building sector accounted for around 32% of final energy use and 8.8 GtCO2 of direct and indirect emissions. This is projected to increase by 50–150% by the middle of the century.	+
−		+
−	It proposes that advances in technologies could stabilise or reduce buildings sector energy use by mid-century and that building codes and standards, have been among the most environmentally and cost-effective instruments for emission reductions. However, there are significant barriers, such as ‘...split incentives (e.g., tenants and builders), fragmented markets and inadequate access to information and financing’.	+
−		+
−	~~= 2018 report~~ =	+

	In October 2018, the IPCC released a report warning that there are only 12 years for global warming to be kept to a maximum of 1.5ºC. Beyond this, they warn, the risks of drought, floods, extreme heat and mass poverty will be significantly worsened.		In October 2018, the IPCC released a report warning that there are only 12 years for global warming to be kept to a maximum of 1.5ºC. Beyond this, they warn, the risks of drought, floods, extreme heat and mass poverty will be significantly worsened.

Editor at 16:27, 5 April 2022

2022-04-05T16:27:32Z

Editor at 16:06, 5 April 2022

2022-04-05T16:06:10Z

Show changes

Editor at 15:11, 5 April 2022

2022-04-05T15:11:51Z

← Older revision		Revision as of 15:11, 5 April 2022
Line 9:		Line 9:
	As with previous reports, the sixth assessment report (AR6) comprises of three working group, with reports issued at various stages as well as a synthesis report:		As with previous reports, the sixth assessment report (AR6) comprises of three working group, with reports issued at various stages as well as a synthesis report:

−	* The Working Group I contribution to the Sixth Assessment Report is entitled [~~https~~:~~//www.ipcc.ch/report/ar6/wg1/~~ Climate Change 2021: The Physical Science Basis] and was released on 9 August 2021.	+	* The Working Group I contribution to the Sixth Assessment Report is entitled [[Climate_change_2021:_the_physical_science_basis_IPCC_report\|Climate Change 2021: The Physical Science Basis]] and was released on 9 August 2021.
−	* The Working Group II contribution to the Sixth Assessment Report is entitled [~~https~~:~~//www.ipcc.ch/report/sixth-assessment-report-working-group-ii/~~ Climate Change 2022: Impacts, Adaptation and Vulnerability] and was released on 28 February 2022.	+	* The Working Group II contribution to the Sixth Assessment Report is entitled [[Climate_change_2022:_impacts,_adaptation_and_vulnerability_IPCC_report\|Climate Change 2022: Impacts, Adaptation and Vulnerability]] and was released on 28 February 2022.
−	* The Working Group III contribution to the Sixth Assessment Report is entitled [~~https~~:~~//www.ipcc.ch/report/sixth-assessment-report-working-group-3/~~ Climate Change 2022: Mitigation of Climate Change] and was released on 4 April 2022.	+	* The Working Group III contribution to the Sixth Assessment Report is entitled [[Climate_change_2022:_mitigation_of_climate_change_IPCC_report\|Climate Change 2022: Mitigation of Climate Change]] and was released on 4 April 2022.
	* The Synthesis Report will be the last of the AR6 products will be considered in Copenhagen, Denmark, on 27-31 October.		* The Synthesis Report will be the last of the AR6 products will be considered in Copenhagen, Denmark, on 27-31 October.

−	To avoid interpretation, the ~~summary~~ text from the 'Summary for Policymakers' ~~has been directly quoted below~~ along with key points and sub-points. These summaries, along with the full reports for all working groups for reports between 2021 and 2022, can be accessed here: [https://www.ipcc.ch/assessment-report/ar6/ https://www.ipcc.ch/assessment-report/ar6/] The final Synthesis report will published towards the end of 2022.	+	To avoid interpretation, the Designing Buildings links above draw text directly from the 'Summary for Policymakers' along with key points and sub-points. These summaries, along with the full reports for all working groups for reports between 2021 and 2022, can be accessed here: [https://www.ipcc.ch/assessment-report/ar6/ https://www.ipcc.ch/assessment-report/ar6/] The final Synthesis report will published towards the end of 2022. Below a brief synopsis is given for each report, also based on the same text.

	= [[Climate_change_2021:_the_physical_science_basis_IPCC_report\|Climate Change 2021: The Physical Science Basis]] =		= [[Climate_change_2021:_the_physical_science_basis_IPCC_report\|Climate Change 2021: The Physical Science Basis]] =
Line 20:		Line 20:
	== A The Current State of the Climate ==		== A The Current State of the Climate ==

−	~~"~~Since AR5, improvements in observationally-based estimates and information from paleoclimate archives provide a comprehensive view of each component of the climate system and its changes to date. New climate model simulations, new analyses, and methods combining multiple lines of evidence lead to improved understanding of human influence on a wider range of climate variables, including weather and climate extremes. The time periods considered throughout this section depend upon the availability of observational products, paleoclimate archives and peer-reviewed studies."	+	Since AR5, improvements in observationally-based estimates and information from paleoclimate archives provide a comprehensive view of each component of the climate system and its changes to date. New climate model simulations, new analyses, and methods combining multiple lines of evidence lead to improved understanding of human influence on a wider range of climate variables, including weather and climate extremes. The time periods considered throughout this section depend upon the availability of observational products, paleoclimate archives and peer-reviewed studies."

	B Possible Climate Futures		B Possible Climate Futures

Editor at 12:05, 5 April 2022

2022-04-05T12:05:25Z

← Older revision		Revision as of 12:05, 5 April 2022
Line 14:		Line 14:
	* The Synthesis Report will be the last of the AR6 products will be considered in Copenhagen, Denmark, on 27-31 October.		* The Synthesis Report will be the last of the AR6 products will be considered in Copenhagen, Denmark, on 27-31 October.

−	To avoid interpretation, the text from the 'Summary for Policymakers' has been directly quoted below along with key points and sub-points. These summaries, along with the full reports for all working groups for reports ~~betwen~~ 2021 and 2022, can be accessed here: [https://www.ipcc.ch/assessment-report/ar6/ https://www.ipcc.ch/assessment-report/ar6/] The final Synthesis report will published towards the end of 2022.	+	To avoid interpretation, the summary text from the 'Summary for Policymakers' has been directly quoted below along with key points and sub-points. These summaries, along with the full reports for all working groups for reports between 2021 and 2022, can be accessed here: [https://www.ipcc.ch/assessment-report/ar6/ https://www.ipcc.ch/assessment-report/ar6/] The final Synthesis report will published towards the end of 2022.

−	= [~~http~~:~~//www.ipcc.ch/report/ar5/wg1/~~ Climate Change 2021: The Physical Science Basis] =	+	= [[Climate_change_2021:_the_physical_science_basis_IPCC_report\|Climate Change 2021: The Physical Science Basis]] =

	== A The Current State of the Climate ==		== A The Current State of the Climate ==
Line 22:		Line 22:
	"Since AR5, improvements in observationally-based estimates and information from paleoclimate archives provide a comprehensive view of each component of the climate system and its changes to date. New climate model simulations, new analyses, and methods combining multiple lines of evidence lead to improved understanding of human influence on a wider range of climate variables, including weather and climate extremes. The time periods considered throughout this section depend upon the availability of observational products, paleoclimate archives and peer-reviewed studies."		"Since AR5, improvements in observationally-based estimates and information from paleoclimate archives provide a comprehensive view of each component of the climate system and its changes to date. New climate model simulations, new analyses, and methods combining multiple lines of evidence lead to improved understanding of human influence on a wider range of climate variables, including weather and climate extremes. The time periods considered throughout this section depend upon the availability of observational products, paleoclimate archives and peer-reviewed studies."

−	* AR6 A.1: It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.	+	B Possible Climate Futures
−	* AR6 A.2: The scale of recent changes across the climate system as a whole – and the present state of many aspects of the climate system – are unprecedented over many centuries to many thousands of years.	+
−	* AR6 A.3: Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. Evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and, in particular, their attribution to human influence, has strengthened.	+
−	* AR6 A.4: Improved knowledge of climate processes, paleoclimate evidence and the response of the climate system to increasing radiative forcing gives a best estimate of equilibrium climate sensitivity of 3°C, with a narrower range compared to AR5	+
−		+
−	== B Possible Climate Futures ==	+

	"A set of five new illustrative emissions scenarios is considered consistently across this Report to explore the climate response to a broader range of greenhouse gas (GHG), land-use and air pollutant futures than assessed in AR5. This set of scenarios drives climate model projections of changes in the climate system. These projections account for solar activity and background forcing from volcanoes. Results over the 21st century are provided for the near term (2021–2040), mid-term (2041–2060) and long term (2081–2100) relative to 1850–1900, unless otherwise stated."		"A set of five new illustrative emissions scenarios is considered consistently across this Report to explore the climate response to a broader range of greenhouse gas (GHG), land-use and air pollutant futures than assessed in AR5. This set of scenarios drives climate model projections of changes in the climate system. These projections account for solar activity and background forcing from volcanoes. Results over the 21st century are provided for the near term (2021–2040), mid-term (2041–2060) and long term (2081–2100) relative to 1850–1900, unless otherwise stated."

−	* AR6 B.1 Global surface temperature will continue to increase until at least mid-century under all emissions scenarios considered. Global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades.	+	C Climate Information for Risk Assessment and Regional Adaptation
−	* AR6 B.2 Many changes in the climate system become larger in direct relation to increasing global warming. They include increases in the frequency and intensity of hot extremes, marine heatwaves, heavy precipitation, and, in some regions, agricultural and ecological droughts; an increase in the proportion of intense tropical cyclones; and reductions in Arctic sea ice, snow cover and permafrost.	+
−	* AR6 B.3 Continued global warming is projected to further intensify the global water cycle, including its variability, global monsoon precipitation and the severity of wet and dry events.	+
−	* AR6 B.4 Under scenarios with increasing CO2 emissions, the ocean and land carbon sinks are projected to be less effective at slowing the accumulation of CO2 in the atmosphere.	+
−	* AR6 B.5 Many changes due to past and future greenhouse gas emissions are irreversible for centuries to millennia, especially changes in the ocean, ice sheets and global sea level.	+
−		+
−	== C Climate Information for Risk Assessment and Regional Adaptation ==	+

	"Physical climate information addresses how the climate system responds to the interplay between human influence, natural drivers and internal variability. Knowledge of the climate response and the range of possible outcomes, including low-likelihood, high impact outcomes, informs climate services, the assessment of climate-related risks, and adaptation planning. Physical climate information at global, regional and local scales is developed from multiple lines of evidence, including observational products, climate model outputs and tailored diagnostics."		"Physical climate information addresses how the climate system responds to the interplay between human influence, natural drivers and internal variability. Knowledge of the climate response and the range of possible outcomes, including low-likelihood, high impact outcomes, informs climate services, the assessment of climate-related risks, and adaptation planning. Physical climate information at global, regional and local scales is developed from multiple lines of evidence, including observational products, climate model outputs and tailored diagnostics."

−	* AR6 C.1 Natural drivers and internal variability will modulate human-caused changes, especially at regional scales and in the near term, with little effect on centennial global warming. These modulations are important to consider in planning for the full range of possible changes.	+	D. Limiting Future Climate Change
−	* AR6 C.2 With further global warming, every region is projected to increasingly experience concurrent and multiple changes in climatic impact-drivers. Changes in several climatic impact-drivers would be more widespread at 2°C compared to 1.5°C global warming and even more widespread and/or pronounced for higher warming levels.	+
−	* AR6 C.3 Low-likelihood outcomes, such as ice-sheet collapse, abrupt ocean circulation changes, some compound extreme events, and warming substantially larger than the assessed very likely range of future warming, cannot be ruled out and are part of risk assessment.	+
−		+
−	== D. Limiting Future Climate Change ==	+

	Since AR5, estimates of remaining carbon budgets have been improved by a new methodology first presented in SR1.5, updated evidence, and the integration of results from multiple lines of evidence. A comprehensive range of possible future air pollution controls in scenarios is used to consistently assess the effects of various assumptions on projections of climate and air pollution. A novel development is the ability to ascertain when climate responses to emissions reductions would become discernible above natural climate variability, including internal variability and responses to natural drivers.		Since AR5, estimates of remaining carbon budgets have been improved by a new methodology first presented in SR1.5, updated evidence, and the integration of results from multiple lines of evidence. A comprehensive range of possible future air pollution controls in scenarios is used to consistently assess the effects of various assumptions on projections of climate and air pollution. A novel development is the ability to ascertain when climate responses to emissions reductions would become discernible above natural climate variability, including internal variability and responses to natural drivers.
−
−	* D.1 From a physical science perspective, limiting human-induced global warming to a specific level requires limiting cumulative CO2 emissions, reaching at least net zero CO2 emissions, along with strong reductions in other greenhouse gas emissions. Strong, rapid and sustained reductions in CH4 emissions would also limit the warming effect resulting from declining aerosol pollution and would improve air quality.
−	* D.2 Scenarios with very low or low GHG emissions (SSP1-1.9 and SSP1-2.6) lead within years to discernible effects on greenhouse gas and aerosol concentrations and air quality, relative to high and very high GHG emissions scenarios (SSP3-7.0 or SSP5-8.5). Under these contrasting scenarios, discernible differences in trends of global surface temperature would begin to emerge from natural variability within around 20 years, and over longer time periods for many other climatic impact-drivers (high confidence).

	= [http://www.ipcc.ch/report/ar5/wg2/ Climate Change 2022: Impacts, Adaptation and Vulnerability] =		= [http://www.ipcc.ch/report/ar5/wg2/ Climate Change 2022: Impacts, Adaptation and Vulnerability] =
Line 65:		Line 47:

	"Since AR5, the knowledge base on observed and projected impacts and risks generated by climate hazards, exposure and vulnerability has increased with impacts attributed to climate change and key risks identified across the report. Impacts and risks are expressed in terms of their damages, harms, economic, and non-economic losses. Risks from observed vulnerabilities and responses to climate change are highlighted. Risks are projected for the near-term (2021–2040), the mid (2041–2060) and long term (2081–2100), at different global warming levels and for pathways that overshoot 1.5°C global warming level for multiple decades27. Complex risks result from multiple climate hazards occurring concurrently, and from multiple risks interacting, compounding overall risk and resulting in risks transmitting through interconnected systems and across regions."		"Since AR5, the knowledge base on observed and projected impacts and risks generated by climate hazards, exposure and vulnerability has increased with impacts attributed to climate change and key risks identified across the report. Impacts and risks are expressed in terms of their damages, harms, economic, and non-economic losses. Risks from observed vulnerabilities and responses to climate change are highlighted. Risks are projected for the near-term (2021–2040), the mid (2041–2060) and long term (2081–2100), at different global warming levels and for pathways that overshoot 1.5°C global warming level for multiple decades27. Complex risks result from multiple climate hazards occurring concurrently, and from multiple risks interacting, compounding overall risk and resulting in risks transmitting through interconnected systems and across regions."
−
−	* B.1 Human-induced climate change, including more frequent and intense extreme events, has caused widespread adverse impacts and related losses and damages to nature and people, beyond natural climate variability. Some development and adaptation efforts have reduced vulnerability. Across sectors and regions the most vulnerable people and systems are observed to be disproportionately affected. The rise in weather and climate extremes has led to some irreversible impacts as natural and human systems are pushed beyond their ability to adapt.
−	* B.2 Vulnerability of ecosystems and people to climate change differs substantially among and within regions (very high confidence), driven by patterns of intersecting socioeconomic development, unsustainable ocean and land use, inequity, marginalization, historical and ongoing patterns of inequity such as colonialism, and governance31 (high confidence). Approximately 3.3 to 3.6 billion people live in contexts that are highly vulnerable to climate change (high confidence). A high proportion of species is vulnerable to climate change (high confidence). Human and ecosystem vulnerability are interdependent (high confidence). Current unsustainable development patterns are increasing exposure of ecosystems and people to climate hazards (high confidence).
−	* B.3 Global warming, reaching 1.5°C in the near-term, would cause unavoidable increases in multiple climate hazards and present multiple risks to ecosystems and humans (very high confidence). The level of risk will depend on concurrent nearterm trends in vulnerability, exposure, level of socioeconomic development and adaptation (high confidence). Near-term actions that limit global warming to close to 1.5°C would substantially reduce projected losses and damages related to climate change in human systems and ecosystems, compared to higher warming levels, but cannot eliminate them all (very high confidence).
−	* B.4 Beyond 2040 and depending on the level of global warming, climate change will lead to numerous risks to natural and human systems (high confidence). For 127 identified key risks, assessed mid- and long-term impacts are up to multiple times higher than currently observed (high confidence). The magnitude and rate of climate change and associated risks depend strongly on near-term mitigation and adaptation actions, and projected adverse impacts and related losses and damages escalate with every increment of global warming (very high confidence).
−	* B.5 Climate change impacts and risks are becoming increasingly complex and more difficult to manage. Multiple climate hazards will occur simultaneously, and multiple climatic and non-climatic risks will interact, resulting in compounding overall risk and risks cascading across sectors and regions. Some responses to climate change result in new impacts and risks. (high confidence)
−	* B.6 If global warming transiently exceeds 1.5°C in the coming decades or later (overshoot)37, then many human and natural systems will face additional severe risks, compared to remaining below 1.5°C (high confidence). Depending on the magnitude and duration of overshoot, some impacts will cause release of additional greenhouse gases (medium confidence) and some will be irreversible, even if global warming is reduced (high confidence)

	== C: Adaptation Measures and Enabling Conditions ==		== C: Adaptation Measures and Enabling Conditions ==

Editor at 11:12, 5 April 2022

2022-04-05T11:12:22Z

← Older revision		Revision as of 11:12, 5 April 2022
Line 11:		Line 11:
	* The Working Group I contribution to the Sixth Assessment Report is entitled [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis] and was released on 9 August 2021.		* The Working Group I contribution to the Sixth Assessment Report is entitled [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis] and was released on 9 August 2021.
	* The Working Group II contribution to the Sixth Assessment Report is entitled [https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/ Climate Change 2022: Impacts, Adaptation and Vulnerability] and was released on 28 February 2022.		* The Working Group II contribution to the Sixth Assessment Report is entitled [https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/ Climate Change 2022: Impacts, Adaptation and Vulnerability] and was released on 28 February 2022.
−	* The Working Group III contribution to the Sixth Assessment Report is entitled Mitigation of Climate Change and was released on 4 April 2022.	+	* The Working Group III contribution to the Sixth Assessment Report is entitled [https://www.ipcc.ch/report/sixth-assessment-report-working-group-3/ Climate Change 2022: Mitigation of Climate Change] and was released on 4 April 2022.
	* The Synthesis Report will be the last of the AR6 products will be considered in Copenhagen, Denmark, on 27-31 October.		* The Synthesis Report will be the last of the AR6 products will be considered in Copenhagen, Denmark, on 27-31 October.

Editor at 10:38, 5 April 2022

2022-04-05T10:38:05Z

Show changes

Editor at 10:13, 5 April 2022

2022-04-05T10:13:55Z

← Older revision		Revision as of 10:13, 5 April 2022
Line 62:		Line 62:
	Resilience in the literature has a wide range of meanings. Adaptation is often organized around resilience as bouncing back and returning to a previous state after a disturbance. More broadly the term describes not just the ability to maintain essential function, identity and structure, but also the capacity for transformation.		Resilience in the literature has a wide range of meanings. Adaptation is often organized around resilience as bouncing back and returning to a previous state after a disturbance. More broadly the term describes not just the ability to maintain essential function, identity and structure, but also the capacity for transformation.

−	* There is significant vulnerability and ~~exposure of some ecosystems~~ and ~~many human systems to current climate variability.~~	+	== B Observed and Projected Impacts and Risks ==
−	* Changing precipitation, melting snow and ice are altering hydrological systems, affecting the quantity and quality of water resources.	+
−	* Species have changed their geographic ranges, seasonal activities, migration patterns, abundances, and species interactions in response to climate change.	+
−	* Negative impacts on crop yields have been more common than positive impacts.	+
−	* Differences in vulnerability are often produced by uneven development processes.	+
−	* Climate-related hazards exacerbate other problems, especially for people living in poverty.	+
−	* Violent conflict increases vulnerability.	+

−	~~It suggests that governments~~ are ~~starting~~ to ~~develop~~ adaptation ~~plans~~ and ~~highlights~~ the ~~fact~~ that near-term adaptation and mitigation ~~choices~~ will ~~affect~~ the risks of climate change throughout the ~~21st century~~.	+	Since AR5, the knowledge base on observed and projected impacts and risks generated by climate hazards, exposure and vulnerability has increased with impacts attributed to climate change and key risks identified across the report. Impacts and risks are expressed in terms of their damages, harms, economic, and non-economic losses. Risks from observed vulnerabilities and responses to climate change are highlighted. Risks are projected for the near-term (2021–2040), the mid (2041–2060) and long term (2081–2100), at different global warming levels and for pathways that overshoot 1.5°C global warming level for multiple decades27. Complex risks result from multiple climate hazards occurring concurrently, and from multiple risks interacting, compounding overall risk and resulting in risks transmitting through interconnected systems and across regions.
		+
		+	* B.1 Human-induced climate change, including more frequent and intense extreme events, has caused widespread adverse impacts and related losses and damages to nature and people, beyond natural climate variability. Some development and adaptation efforts have reduced vulnerability. Across sectors and regions the most vulnerable people and systems are observed to be disproportionately affected. The rise in weather and climate extremes has led to some irreversible impacts as natural and human systems are pushed beyond their ability to adapt.
		+	* B.2 Vulnerability of ecosystems and people to climate change differs substantially among and within regions (very high confidence), driven by patterns of intersecting socioeconomic development, unsustainable ocean and land use, inequity, marginalization, historical and ongoing patterns of inequity such as colonialism, and governance31 (high confidence). Approximately 3.3 to 3.6 billion people live in contexts that are highly vulnerable to climate change (high confidence). A high proportion of species is vulnerable to climate change (high confidence). Human and ecosystem vulnerability are interdependent (high confidence). Current unsustainable development patterns are increasing exposure of ecosystems and people to climate hazards (high confidence).
		+	* B.3 Global warming, reaching 1.5°C in the near-term, would cause unavoidable increases in multiple climate hazards and present multiple risks to ecosystems and humans (very high confidence). The level of risk will depend on concurrent nearterm trends in vulnerability, exposure, level of socioeconomic development and adaptation (high confidence). Near-term actions that limit global warming to close to 1.5°C would substantially reduce projected losses and damages related to climate change in human systems and ecosystems, compared to higher warming levels, but cannot eliminate them all (very high confidence).
		+	* B.4 Beyond 2040 and depending on the level of global warming, climate change will lead to numerous risks to natural and human systems (high confidence). For 127 identified key risks, assessed mid- and long-term impacts are up to multiple times higher than currently observed (high confidence). The magnitude and rate of climate change and associated risks depend strongly on near-term mitigation and adaptation actions, and projected adverse impacts and related losses and damages escalate with every increment of global warming (very high confidence).
		+	* B.5 Climate change impacts and risks are becoming increasingly complex and more difficult to manage. Multiple climate hazards will occur simultaneously, and multiple climatic and non-climatic risks will interact, resulting in compounding overall risk and risks cascading across sectors and regions. Some responses to climate change result in new impacts and risks. (high confidence)
		+	* B.6 If global warming transiently exceeds 1.5°C in the coming decades or later (overshoot)37, then many human and natural systems will face additional severe risks, compared to remaining below 1.5°C (high confidence). Depending on the magnitude and duration of overshoot, some impacts will cause release of additional greenhouse gases (medium confidence) and some will be irreversible, even if global warming is reduced (high confidence)
		+
		+	== C: Adaptation Measures and Enabling Conditions ==
		+
		+	Adaptation, in response to current climate change, is reducing climate risks and vulnerability mostly via adjustment of existing systems. Many adaptation options exist and are used to help manage projected climate change impacts, but their implementation depends upon the capacity and effectiveness of governance and decision-making processes. These and other enabling conditions can also support climate-resilient development (Section D).
		+
		+	C.1 Progress in adaptation planning and implementation has been observed across all sectors and regions, generating multiple benefits (very high confidence). However, adaptation progress is unevenly distributed with observed adaptation gaps40 (high confidence). Many initiatives prioritize immediate and near-term climate risk reduction which reduces the opportunity for transformational adaptation (high confidence).
		+
		+	C.2 There are feasible41 and effective42 adaptation options which can reduce risks to people and nature. The feasibility of implementing adaptation options in the near-term differs across sectors and regions (very high confidence). The effectiveness of adaptation to reduce climate risk is documented for specific contexts, sectors and regions (high confidence) and will decrease with increasing warming (high confidence). Integrated, multi-sectoral solutions that address social inequities, differentiate responses based on climate risk and cut across systems, increase the feasibility and effectiveness of adaptation in multiple sectors (high confidence)
		+
		+	C.3 Soft limits to some human adaptation have been reached, but can be overcome by addressing a range of constraints, primarily financial, governance, institutional and policy constraints (high confidence). Hard limits to adaptation have been reached in some ecosystems (high confidence). With increasing global warming, losses and damages will increase and additional human and natural systems will reach adaptation limits (high confidence).
		+
		+	C.4 There is increased evidence of maladaptation15 across many sectors and regions since the AR5. Maladaptive responses to climate change can create lock-ins of vulnerability, exposure and risks that are difficult and expensive to change and exacerbate existing inequalities. Maladaptation can be avoided by flexible, multi-sectoral, inclusive and long-term planning and implementation of adaptation actions with benefits to many sectors and systems. (high confidence)
		+
		+	C.5 Enabling conditions are key for implementing, accelerating and sustaining adaptation in human systems and ecosystems. These include political commitment and follow-through, institutional frameworks, policies and instruments with clear goals and priorities, enhanced knowledge on impacts and solutions, mobilization of and access to adequate financial resources, monitoring and evaluation, and inclusive governance processes. (high confidence)
		+
		+	== D Climate Resilient Development ==
		+
		+	Climate resilient development integrates adaptation measures and their enabling conditions (Section C) with mitigation to advance sustainable development for all. Climate resilient development involves questions of equity and system transitions in land, ocean and ecosystems; urban and infrastructure; energy; industry; and society and includes adaptations for human, ecosystem and planetary health. Pursuing climate resilient development focuses on both where people and ecosystems are co-located as well as the protection and maintenance of ecosystem function at the planetary scale. Pathways for advancing climate resilient development are development trajectories that successfully integrate mitigation and adaptation actions to advance sustainable development. Climate resilient development pathways may be temporarily coincident with any RCP and SSP scenario used throughout AR6, but do not follow any particular scenario in all places and over all time.
		+
		+	D.1 Evidence of observed impacts, projected risks, levels and trends in vulnerability, and adaptation limits, demonstrate that worldwide climate resilient development action is more urgent than previously assessed in AR5. Comprehensive, effective, and innovative responses can harness synergies and reduce trade-offs between adaptation and mitigation to advance sustainable development. (very high confidence)
		+
		+	D.2 Climate resilient development is enabled when governments, civil society and the private sector make inclusive development choices that prioritise risk reduction, equity and justice, and when decision-making processes, finance and actions are integrated across governance levels, sectors and timeframes (very high confidence). Climate resilient development is facilitated by international cooperation and by governments at all levels working with communities, civil society, educational bodies, scientific and other institutions, media, investors and businesses; and by developing partnerships with traditionally marginalised groups, including women, youth, Indigenous Peoples, local communities and ethnic minorities (high confidence). These partnerships are most effective when supported by enabling political leadership, institutions, resources, including finance, as well as climate services, information and decision support tools (high confidence).
		+
		+	D.3 Interactions between changing urban form, exposure and vulnerability can create climate change-induced risks and losses for cities and settlements. However, the global trend of urbanisation also offers a critical opportunity in the near-term, to advance climate resilient development (high confidence). Integrated, inclusive planning and investment in everyday decision-making about urban infrastructure, including social, ecological and grey/physical infrastructures, can significantly increase the adaptive capacity of urban and rural settlements. Equitable outcomes contributes to multiple benefits for health and well-being and ecosystem services, including for Indigenous Peoples, marginalised and vulnerable communities (high confidence). Climate resilient development in urban areas also supports adaptive capacity in more rural places through maintaining peri-urban supply chains of goods and services and financial flows (medium confidence). Coastal cities and settlements play an especially important role in advancing climate resilient development (high confidence).
		+
		+	D.4 Safeguarding biodiversity and ecosystems is fundamental to climate resilient development, in light of the threats climate change poses to them and their roles in adaptation and mitigation (very high confidence). Recent analyses, drawing on a range of lines of evidence, suggest that maintaining the resilience of biodiversity and ecosystem services at a global scale depends on effective and equitable conservation of approximately 30% to 50% of Earth’s land, freshwater and ocean areas, including currently near-natural ecosystems (high confidence).
		+
		+	D.5 It is unequivocal that climate change has already disrupted human and natural systems. Past and current development trends (past emissions, development and climate change) have not advanced global climate resilient development (very high confidence). Societal choices and actions implemented in the next decade determine the extent to which medium and long-term pathways will deliver higher or lower climate resilient development (high confidence). Importantly 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 (high confidence). These prospects are constrained by past development, emissions and climate change, and enabled by inclusive governance, adequate and appropriate human and technological resources, information, capacities and finance (high confidence).

	= [http://www.ipcc.ch/report/ar5/wg3/ Climate Change 2014: Mitigation of Climate Change] =		= [http://www.ipcc.ch/report/ar5/wg3/ Climate Change 2014: Mitigation of Climate Change] =

Editor at 09:53, 5 April 2022

2022-04-05T09:53:07Z

← Older revision		Revision as of 09:53, 5 April 2022
Line 5:		Line 5:
	The IPCC does not carry out research itself, but reviews and assesses existing research and other information. Thousands of scientists contribute voluntarily to the work of the IPCC in order that it can reflect a wide range of views and expertise. 195 countries are members of the IPCC, participating in the review process and the plenary sessions.		The IPCC does not carry out research itself, but reviews and assesses existing research and other information. Thousands of scientists contribute voluntarily to the work of the IPCC in order that it can reflect a wide range of views and expertise. 195 countries are members of the IPCC, participating in the review process and the plenary sessions.

−	Its main activity is to provide regular Assessment Reports (AR) on the state of knowledge about climate change. It has produced reports in 1990, 1995, 2001, 2007 ~~and most~~ recently, the ~~fifth~~ assessment report (~~AR5~~) published in stages between ~~2013~~ and ~~2014~~. The IPCC also ~~produces;~~ special reports, methodology reports, technical papers and supporting material.	+	Its main activity is to provide regular Assessment Reports (AR) on the state of knowledge about climate change. It has produced reports in 1990, 1995, 2001, 2007, 2013 & 2014. Most recently, the sixth assessment report (AR6), described as the sixth assessment cycle, is being published in stages between 2020 and 2022. The IPCC has also produced various special reports, methodology reports, technical papers and supporting material published a regular intervals.

−	~~The fifth~~ assessment report (~~AR5~~) comprises three working group reports ~~and~~ a synthesis report:	+	As with previous reports, the sixth assessment report (AR6) comprises of three working group, with reports issued at various stages as well as a synthesis report:

−	* Climate Change ~~2013~~: The Physical Science Basis.	+	* The Working Group I contribution to the Sixth Assessment Report is entitled [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis] and was released on 9 August 2021.
−	* Climate Change ~~2014~~: Impacts, Adaptation and Vulnerability.	+	* The Working Group II contribution to the Sixth Assessment Report is entitled [https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/ Climate Change 2022: Impacts, Adaptation and Vulnerability] and was released on 28 February 2022.
−	* ~~Climate Change 2014:~~ Mitigation of Climate Change.	+	* The Working Group III contribution to the Sixth Assessment Report is entitled Mitigation of Climate Change and was released on 4 April 2022.
−	* The Synthesis Report will be considered in Copenhagen, Denmark, on 27-31 October.	+	* The Synthesis Report will be the last of the AR6 products will be considered in Copenhagen, Denmark, on 27-31 October.

−	= [~~http~~://www.ipcc.ch/report/~~ar5~~/~~wg1/ Climate Change 2013~~: ~~The Physical Science Basis~~] =	+	To avoid interpretation, the text from the 'Summary for Policymakers' has been directly quoted below along with key points and sub-points. These summaries, along with the full reports for all working groups for reports betwen 2021 and 2022, can be accessed here: [https://www.ipcc.ch/assessment-report/ar6/ https://www.ipcc.ch/assessment-report/ar6/] The final Synthesis report will published towards the end of 2022.

−	~~AR5~~: The Physical Science Basis, suggests amongst other things that; greenhouse gas concentrations are increasing, the global temperature is increasing, the sea temperature is increasing, the ice sheets are melting and sea levels are rising.	+	= [http://www.ipcc.ch/report/ar5/wg1/ Climate Change 2021: The Physical Science Basis] =

−	~~It proposes that ‘Human influence on the climate system is clear’, and that ‘Continued emissions of greenhouse gases will cause further warming and changes in all components~~ of the ~~climate system.’~~	+	== A The Current State of the Climate ==

−	~~It suggests that limiting climate change will require substantial~~ and ~~sustained reductions~~ of ~~greenhouse gas emissions~~, ~~but that even if this happens~~, ~~most aspects~~ of climate ~~change will persist for many centuries~~.	+	Since AR5, improvements in observationally-based estimates and information from paleoclimate archives provide a comprehensive view of each component of the climate system and its changes to date. New climate model simulations, new analyses, and methods combining multiple lines of evidence lead to improved understanding of human influence on a wider range of climate variables, including weather and climate extremes. The time periods considered throughout this section depend upon the availability of observational products, paleoclimate archives and peer-reviewed studies.

−	~~= [http~~:~~//www~~.~~ipcc~~.~~ch/report/ar5/wg2/ Climate Change 2014~~: ~~Impacts~~, ~~Adaptation~~ and ~~Vulnerability] =~~	+	* AR6 A.1: It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.
		+	* AR6 A.2: The scale of recent changes across the climate system as a whole – and the present state of many aspects of the climate system – are unprecedented over many centuries to many thousands of years.
		+	* AR6 A.3: Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. Evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and, in particular, their attribution to human influence, has strengthened since AR5.
		+	* AR6 A.4: Improved knowledge of climate processes, paleoclimate evidence and the response of the climate system to increasing radiative forcing gives a best estimate of equilibrium climate sensitivity of 3°C, with a narrower range compared to AR5

−	AR5: Impacts, Adaptation and Vulnerability, ~~suggests~~, ~~with varying degrees~~ of ~~confidence~~ that:	+	== B Possible Climate Futures ==
		+
		+	A set of five new illustrative emissions scenarios is considered consistently across this Report to explore the climate response to a broader range of greenhouse gas (GHG), land-use and air pollutant futures than assessed in AR5. This set of scenarios drives climate model projections of changes in the climate system. These projections account for solar activity and background forcing from volcanoes. Results over the 21st century are provided for the near term (2021–2040), mid-term (2041–2060) and long term (2081–2100) relative to 1850–1900, unless otherwise stated.
		+
		+	* AR6 B.1 Global surface temperature will continue to increase until at least mid-century under all emissions scenarios considered. Global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades.
		+	* AR6 B.2 Many changes in the climate system become larger in direct relation to increasing global warming. They include increases in the frequency and intensity of hot extremes, marine heatwaves, heavy precipitation, and, in some regions, agricultural and ecological droughts; an increase in the proportion of intense tropical cyclones; and reductions in Arctic sea ice, snow cover and permafrost.
		+	* AR6 B.3 Continued global warming is projected to further intensify the global water cycle, including its variability, global monsoon precipitation and the severity of wet and dry events.
		+	* AR6 B.4 Under scenarios with increasing CO2 emissions, the ocean and land carbon sinks are projected to be less effective at slowing the accumulation of CO2 in the atmosphere.
		+	* AR6 B.5 Many changes due to past and future greenhouse gas emissions are irreversible for centuries to millennia, especially changes in the ocean, ice sheets and global sea level.
		+
		+	== C Climate Information for Risk Assessment and Regional Adaptation ==
		+
		+	Physical climate information addresses how the climate system responds to the interplay between human influence, natural drivers and internal variability. Knowledge of the climate response and the range of possible outcomes, including low-likelihood, high impact outcomes, informs climate services, the assessment of climate-related risks, and adaptation planning. Physical climate information at global, regional and local scales is developed from multiple lines of evidence, including observational products, climate model outputs and tailored diagnostics.
		+
		+	* AR6 C.1 Natural drivers and internal variability will modulate human-caused changes, especially at regional scales and in the near term, with little effect on centennial global warming. These modulations are important to consider in planning for the full range of possible changes.
		+	* AR6 C.2 With further global warming, every region is projected to increasingly experience concurrent and multiple changes in climatic impact-drivers. Changes in several climatic impact-drivers would be more widespread at 2°C compared to 1.5°C global warming and even more widespread and/or pronounced for higher warming levels.
		+	* AR6 C.3 Low-likelihood outcomes, such as ice-sheet collapse, abrupt ocean circulation changes, some compound extreme events, and warming substantially larger than the assessed very likely range of future warming, cannot be ruled out and are part of risk assessment.
		+
		+	== D. Limiting Future Climate Change ==
		+
		+	Since AR5, estimates of remaining carbon budgets have been improved by a new methodology first presented in SR1.5, updated evidence, and the integration of results from multiple lines of evidence. A comprehensive range of possible future air pollution controls in scenarios is used to consistently assess the effects of various assumptions on projections of climate and air pollution. A novel development is the ability to ascertain when climate responses to emissions reductions would become discernible above natural climate variability, including internal variability and responses to natural drivers.
		+
		+	* D.1 From a physical science perspective, limiting human-induced global warming to a specific level requires limiting cumulative CO2 emissions, reaching at least net zero CO2 emissions, along with strong reductions in other greenhouse gas emissions. Strong, rapid and sustained reductions in CH4 emissions would also limit the warming effect resulting from declining aerosol pollution and would improve air quality.
		+	* D.2 Scenarios with very low or low GHG emissions (SSP1-1.9 and SSP1-2.6) lead within years to discernible effects on greenhouse gas and aerosol concentrations and air quality, relative to high and very high GHG emissions scenarios (SSP3-7.0 or SSP5-8.5). Under these contrasting scenarios, discernible differences in trends of global surface temperature would begin to emerge from natural variability within around 20 years, and over longer time periods for many other climatic impact-drivers (high confidence).
		+
		+	= [http://www.ipcc.ch/report/ar5/wg2/ Climate Change 2022: Impacts, Adaptation and Vulnerability] =
		+
		+	== A Introduction ==
		+
		+	Across all three AR6 working groups, risk provides a framework for understanding the increasingly severe, interconnected and often irreversible impacts of climate change on ecosystems, biodiversity, and human systems; differing impacts across regions, sectors and communities; and how to best reduce adverse consequences for current and future generations. In the context of climate change, risk can arise from the dynamic interactions among climate-related hazards (see Working Group I), the exposure and vulnerability8 of affected human and ecological systems. The risk that can be introduced by human responses to climate change is a new aspect considered in the risk concept. This report identifies 127 key risks.
		+
		+	Adaptation plays a key role in reducing exposure and vulnerability to climate change. Adaptation in ecological systems includes autonomous adjustments through ecological and evolutionary processes. In human systems, adaptation can be anticipatory or reactive, as well as incremental and/ or transformational. The latter changes the fundamental attributes of a social-ecological system in anticipation of climate change and its impacts. Adaptation is subject to hard and soft limits11.
		+
		+	Resilience in the literature has a wide range of meanings. Adaptation is often organized around resilience as bouncing back and returning to a previous state after a disturbance. More broadly the term describes not just the ability to maintain essential function, identity and structure, but also the capacity for transformation.

	* There is significant vulnerability and exposure of some ecosystems and many human systems to current climate variability.		* There is significant vulnerability and exposure of some ecosystems and many human systems to current climate variability.

← Older revision		Revision as of 16:27, 5 April 2022
Line 106:		Line 106:
	C.8 Demand-side options and low-GHG emissions technologies can reduce transport sector emissions in developed countries and limit emissions growth in developing countries. Demand-focused interventions can reduce demand for all transport services and support the shift to energy efficient modes. Electric vehicles powered by low emissions electricity offer the largest decarbonisation potential for land-based transport, on a life cycle basis. Sustainable biofuels can offer additional mitigation benefits in land-based transport in the short and medium term. Sustainable biofuels, low emissions hydrogen, and derivatives (including synthetic fuels) can support mitigation of CO2 emissions from shipping, aviation, and heavy-duty land transport but require production process improvements and cost reductions. Many mitigation strategies in transport would have various co-benefits, including air quality improvements, health benefits, equitable access to transportation services, reduced congestion, and reduced material demand.		C.8 Demand-side options and low-GHG emissions technologies can reduce transport sector emissions in developed countries and limit emissions growth in developing countries. Demand-focused interventions can reduce demand for all transport services and support the shift to energy efficient modes. Electric vehicles powered by low emissions electricity offer the largest decarbonisation potential for land-based transport, on a life cycle basis. Sustainable biofuels can offer additional mitigation benefits in land-based transport in the short and medium term. Sustainable biofuels, low emissions hydrogen, and derivatives (including synthetic fuels) can support mitigation of CO2 emissions from shipping, aviation, and heavy-duty land transport but require production process improvements and cost reductions. Many mitigation strategies in transport would have various co-benefits, including air quality improvements, health benefits, equitable access to transportation services, reduced congestion, and reduced material demand.

−	C.9 ~~AFOLU~~ mitigation options, when sustainably implemented, can deliver large-scale GHG emission reductions and enhanced removals, but cannot fully compensate for delayed action in other sectors. ~~In addition, sustainably~~ sourced agricultural and forest products can be used instead of more GHG intensive products in other sectors. Barriers to implementation and trade- offs may result from the impacts of climate change, competing demands on land, conflicts with food security and livelihoods, the complexity of land ownership and management systems, and cultural aspects. There are many country-specific opportunities to provide co-benefits (such as biodiversity conservation, ecosystem services, and livelihoods) and avoid risks (for example, through adaptation to climate change). ~~(high confidence) {7.4, 7.6, 7.7, 12.5, 12.6}~~	+	C.9 Agriculture farming and other land use (FAOLU) mitigation options, when sustainably implemented, can deliver large-scale GHG emission reductions and enhanced removals, but cannot fully compensate for delayed action in other sectors. Sustainably sourced agricultural and forest products can be used instead of more GHG intensive products in other sectors. Barriers to implementation and trade- offs may result from the impacts of climate change, competing demands on land, conflicts with food security and livelihoods, the complexity of land ownership and management systems, and cultural aspects. There are many country-specific opportunities to provide co-benefits (such as biodiversity conservation, ecosystem services, and livelihoods) and avoid risks (for example, through adaptation to climate change).

−	C.10 Demand-side mitigation encompasses changes in infrastructure use, end-use technology adoption, and socio-cultural and behavioural change. Demand-side measures and new ways of end-use service provision can reduce global GHG emissions in end use sectors by 40-70% by 2050 compared to baseline scenarios, while some regions and socioeconomic groups require additional energy and resources. Demand side mitigation response options are consistent with improving basic wellbeing for all. ~~(high confidence) (Figure SPM.6) {5.3, 5.4, Figure 5.6, Figure 5.14, 8.2, 9.4, 10.2, 11.3, 11.4, 12.4, Figure TS.22}~~	+	C.10 Demand-side mitigation encompasses changes in infrastructure use, end-use technology adoption, and socio-cultural and behavioural change. Demand-side measures and new ways of end-use service provision can reduce global GHG emissions in end use sectors by 40-70% by 2050 compared to baseline scenarios, while some regions and socioeconomic groups require additional energy and resources. Demand side mitigation response options are consistent with improving basic wellbeing for all.

−	C.11 The deployment of CDR to counterbalance hard-to-abate residual emissions is unavoidable if net zero CO2 or GHG emissions are to be achieved. The scale and timing of deployment will depend on the trajectories of gross emission reductions in different sectors. Upscaling the deployment of CDR depends on developing effective approaches to address feasibility and sustainability constraints especially at large scales. ~~(high confidence) {3.4, 7.4, 12.3, Cross-Chapter Box 8 in Chapter 12}~~	+	C.11 The deployment of carbon dioxide removal (CDR) to counterbalance hard-to-abate residual emissions is unavoidable if net zero CO2 or GHG emissions are to be achieved. The scale and timing of deployment will depend on the trajectories of gross emission reductions in different sectors. Upscaling the deployment of CDR depends on developing effective approaches to address feasibility and sustainability constraints especially at large scales.

−	C.12 Mitigation options costing USD100 tCO2-eq-1 or less could reduce global GHG emissions by at least half the 2019 level by 2030 ~~(high confidence)~~. Global GDP continues to grow in modelled pathways ~~[FOOTNOTE 65]~~ but, without accounting for the economic benefits of mitigation action from avoided damages from climate change nor from reduced adaptation costs, it is a few percent lower in 2050 compared to pathways without mitigation beyond current policies. The global economic benefit of limiting warming to 2°C is reported to exceed the cost of mitigation in most of the assessed literature. ~~(medium confidence) (Figure SPM.7) {3.6, 3.8, Cross- Working Group Box 1 in Chapter 3, 12.2, Box TS.7}~~	+	C.12 Mitigation options costing USD100 tCO2-eq-1 or less could reduce global GHG emissions by at least half the 2019 level by 2030. Global GDP continues to grow in modelled pathways but, without accounting for the economic benefits of mitigation action from avoided damages from climate change nor from reduced adaptation costs, it is a few percent lower in 2050 compared to pathways without mitigation beyond current policies. The global economic benefit of limiting warming to 2°C is reported to exceed the cost of mitigation in most of the assessed literature.

	== D. Linkages between mitigation, adaptation, and sustainable development ==		== D. Linkages between mitigation, adaptation, and sustainable development ==

−	D.1 Accelerated and equitable climate action in mitigating, and adapting to, climate change impacts is critical to sustainable development. Climate change actions can also result in ~~some~~ trade-offs. The trade-offs of individual options could be managed through policy design. The Sustainable Development Goals (SDGs) adopted under the UN 2030 Agenda for Sustainable Development can be used as a basis for evaluating climate action in the context of sustainable development. ~~(high confidence) (Figure SPM.8) {1.6, 3.7, 17.3, Figure TS.29}~~	+	D.1 Accelerated and equitable climate action in mitigating, and adapting to, climate change impacts is critical to sustainable development. Climate change actions can also result in trade-offs. The trade-offs of individual options could be managed through policy design. The Sustainable Development Goals (SDGs) adopted under the UN 2030 Agenda for Sustainable Development can be used as a basis for evaluating climate action in the context of sustainable development.

−	D.2 There is a strong link between sustainable development, vulnerability and climate risks. Limited economic, social and institutional resources often result in high vulnerability and low adaptive capacity, especially in developing countries ~~(medium confidence)~~. Several response options deliver both mitigation and adaptation outcomes, especially in human settlements , land management, and in relation to ecosystems. However, land and aquatic ecosystems can be adversely affected by some mitigation actions, depending on their implementation ~~(medium confidence)~~. Coordinated cross-sectoral policies and planning can maximise synergies and avoid or reduce trade-offs between mitigation and adaptation ~~(high confidence)~~. ~~{3.7, 4.4, 13.8, 17.3, WG II}~~	+	D.2 There is a strong link between sustainable development, vulnerability and climate risks. Limited economic, social and institutional resources often result in high vulnerability and low adaptive capacity, especially in developing countries. Several response options deliver both mitigation and adaptation outcomes, especially in human settlements, land management, and in relation to ecosystems. However, land and aquatic ecosystems can be adversely affected by some mitigation actions, depending on their implementation. Coordinated cross-sectoral policies and planning can maximise synergies and avoid or reduce trade-offs between mitigation and adaptation.

−	D.3 Enhanced mitigation and broader action to shift development pathways towards sustainability will have distributional consequences within and between countries. Attention to equity ~~and~~ broad and meaningful participation of all relevant actors in decision-making at all scales can build social trust, and deepen and widen support for transformative changes. ~~(high confidence) {3.6, 4.2, 4.5, 5.2, 13.2, 17.3, 17.4}~~	+	D.3 Enhanced mitigation and broader action to shift development pathways towards sustainability will have distributional consequences within and between countries. Attention to equity, broad and meaningful participation of all relevant actors in decision-making at all scales can build social trust, and deepen and widen support for transformative changes.

	== E. Strengthening the response ==		== E. Strengthening the response ==

−	E.1 There are mitigation options which are feasible ~~[FOOTNOTE 72]~~ to deploy at scale in the near term. Feasibility differs across sectors and regions, and according to capacities and the speed and scale of implementation. Barriers to feasibility would need to be reduced or removed, and enabling conditions ~~[FOOTNOTE 73]~~ strengthened to deploy mitigation options at scale. These barriers and enablers include geophysical, environmental-ecological, technological, and economic factors, and especially institutional and socio-cultural factors. Strengthened near-term action beyond the NDCs ~~(announced prior to UNFCCC COP26)~~ can reduce and/or avoid long-term feasibility challenges of global modelled pathways that limit warming to 1.5 °C (>50%) with no or limited overshoot. ~~(high confidence) {3.8, 6.4, 8.5, 9.9, 10.8, 12.3, Figure TS.31, Annex II Part IV Section 11}~~	+	E.1 There are mitigation options which are feasible to deploy at scale in the near term. Feasibility differs across sectors and regions, and according to capacities and the speed and scale of implementation. Barriers to feasibility would need to be reduced or removed, and enabling conditions strengthened to deploy mitigation options at scale. These barriers and enablers include geophysical, environmental-ecological, technological, and economic factors, and especially institutional and socio-cultural factors. Strengthened near-term action beyond the NDCs can reduce and/or avoid long-term feasibility challenges of global modelled pathways that limit warming to 1.5 °C (>50%) with no or limited overshoot.

−	E.2 In all countries, mitigation efforts embedded within the wider development context can increase the pace, depth and breadth of emissions reductions ~~(medium confidence)~~. Policies that shift development pathways towards sustainability can broaden the portfolio of available mitigation responses, and enable the pursuit of synergies with development objectives ~~(medium confidence)~~. Actions can be taken now to shift development pathways and accelerate mitigation and transitions across systems ~~(high confidence)~~. ~~{4.3, 4.4, Cross-Chapter Box 5 in Chapter 4, 5.2, 5.4, 13.9, 14.5, 15.6, 16.3, 16.4, 16.5}~~	+	E.2 In all countries, mitigation efforts embedded within the wider development context can increase the pace, depth and breadth of emissions reductions. Policies that shift development pathways towards sustainability can broaden the portfolio of available mitigation responses, and enable the pursuit of synergies with development objectives. Actions can be taken now to shift development pathways and accelerate mitigation and transitions across systems.

−	E.3 Climate governance, acting through laws, strategies and institutions, based on national circumstances, supports mitigation by providing frameworks through which diverse actors interact, and a basis for policy development and implementation ~~(medium confidence)~~. Climate governance is most effective when it integrates ~~across~~ multiple policy domains, helps realise synergies ~~and~~ minimize trade-offs, ~~and connects~~ national and sub-national policy-making ~~levels (high confidence)~~. Effective ~~and~~ equitable climate governance builds on engagement with civil society ~~actors~~, political actors, businesses, youth, labour, media, Indigenous Peoples and ~~local~~ communities ~~(medium confidence). {5.4, 5.6, 8.5, 9.9, 13.2, 13.7, 13~~.9}	+	E.3 Climate governance, acting through laws, strategies and institutions, based on national circumstances, supports mitigation by providing frameworks through which diverse actors interact, and a basis for policy development and implementation. Climate governance is most effective when it integrates multiple policy domains, helps realise synergies minimize trade-offs, connecting national and sub-national policy-making. Effective, equitable climate governance builds on engagement with civil society, political actors, businesses, youth, labour, media, Indigenous Peoples and communities.

−	E.4 ~~Many regulatory~~ and economic instruments have already been deployed successfully. Instrument design can help address equity and other objectives. These ~~instruments~~ could support deep emissions reductions and stimulate innovation if scaled up and applied more widely ~~(high confidence)~~. Policy packages that enable innovation and build capacity are better able to support a shift towards equitable low-emission futures than are individual policies ~~(high confidence)~~. Economy-wide packages, consistent with national circumstances, can meet short-term economic goals while reducing emissions ~~and~~ shifting ~~development~~ pathways towards sustainability ~~(medium confidence)~~. ~~{13.6, 13.7, 13.9, 16.3, 16.4, 16.6, Cross-Chapter Box 5 in Chapter 4}~~	+	E.4 Regulatory and economic instruments have already been deployed successfully. Instrument design can help address equity and other objectives. These could support deep emissions reductions and stimulate innovation if scaled up and applied more widely. Policy packages that enable innovation and build capacity are better able to support a shift towards equitable low-emission futures than are individual policies. Economy-wide packages, consistent with national circumstances, can meet short-term economic goals while reducing emissions, shifting pathways towards sustainability.

	E.5 Tracked financial flows fall short of the levels needed to achieve mitigation goals across all sectors and regions. The challenge of closing gaps is largest in developing countries as a whole. Scaling up mitigation financial flows can be supported by clear policy choices and signals from governments and the international community. (high confidence) Accelerated international financial cooperation is a critical enabler of low-GHG and just transitions, and can address inequities in access to finance and the costs of, and vulnerability to, the impacts of climate change		E.5 Tracked financial flows fall short of the levels needed to achieve mitigation goals across all sectors and regions. The challenge of closing gaps is largest in developing countries as a whole. Scaling up mitigation financial flows can be supported by clear policy choices and signals from governments and the international community. (high confidence) Accelerated international financial cooperation is a critical enabler of low-GHG and just transitions, and can address inequities in access to finance and the costs of, and vulnerability to, the impacts of climate change

−	E.6 International cooperation is a critical enabler for achieving ambitious climate change mitigation goals. The UNFCCC, Kyoto Protocol, and Paris Agreement are supporting rising levels of national ambition and encouraging development and implementation of climate policies, although gaps remain. Partnerships, agreements, institutions and initiatives operating at the sub- global and sectoral levels and engaging multiple actors are emerging, with mixed levels of effectiveness. ~~(high confidence) {8.5, 14.2, 14.3, 14.5, 14.6, 15.6, 16.5}~~	+	E.6 International cooperation is a critical enabler for achieving ambitious climate change mitigation goals. The UNFCCC, Kyoto Protocol, and Paris Agreement are supporting rising levels of national ambition and encouraging development and implementation of climate policies, although gaps remain. Partnerships, agreements, institutions and initiatives operating at the sub- global and sectoral levels and engaging multiple actors are emerging, with mixed levels of effectiveness.

	Proposals for mitigation include:		Proposals for mitigation include: