Editing IPCC:AR6/WGII/TS (section)

=== Limits to adaptation ===

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'''TS.D.2 There is increasing evidence on limits to adaptation which result from the interaction of adaptation constraints and the speed of change (''' '''''high confidence''''' '''). In some natural systems, hard limits have been reached (''' '''''high confidence''''' ''') and more will be reached beyond 1.5°C (''' '''''medium confidence''''' '''). Surpassing such hard, evolutionary limits causes local species extinctions and displacements if suitable habitats exist (''' '''''high confidence''''' '''). Otherwise, species’ existence is at very high risk (''' '''''high confidence''''' '''). In human, managed and natural systems, soft limits are already being experienced (''' '''''high confidence''''' '''). Financial constraints are key determinants of adaptation limits in human and managed systems, particularly in low-income settings (''' '''''high confidence''''' '''), while in natural systems key determinants for limits are inherent traits of the species or ecosystem (''' '''''very high confidence''''' '''). (''' Figure TS.7 VULNERABILITY) { 2.4.2, 2.6.1, 3.3, 3.4.2, 3.4.3, 15.5.4, [https://www.ipcc.ch/chapter/ts#CCP5.3.2 CCP5.3.2] , [https://www.ipcc.ch/chapter/ts#CCP7.5.2 CCP7.5.2] , CCB EXTREMES }

'''TS.D.2.1 Adaptation limits can be differentiated into hard and soft limits.''' Soft limits are those for which no further adaptation options are feasible currently but might become available in the future. Hard limits are those for which existing adaptation options will cease to be effective and additional options are not possible. Hard limits will increasingly emerge at higher levels of warming ( ''high confidence'' ). Adaptation limits are shaped by constraints that can or cannot be overcome by adaptation actions and by the speed with which climate impacts unfold. Evidence and signals of the thresholds at which constraints result in limits is still sparse and, in human systems, are expected to remain contested even with increasing knowledge ( ''high confidence'' ). { 2.4.2, 2.6.1, 4.7.4, Box 4.2, Box 4.3, 15.3.4, 15.5.4, 16.4.1, 16.4.2, 16.4.3, CCB EXTREMES }

'''TS.D.2.2 Limits to adaptation have been observed for terrestrial and aquatic species and ecosystems and for some human and managed systems in specific geographies such as small island states and mountain regions (''' '''''high confidence''''' ''').''' Beginning at below 1.5°C, autonomous and evolutionary adaptation responses by more terrestrial and aquatic species and ecosystems will face hard limits, resulting in species extinctions, loss of ecosystem integrity and a resulting loss of livelihoods ( ''high confidence'' ). Examples of hard limits being exceeded include observed population losses and species extinctions and loss of whole ecosystems from certain locations (e.g., irrecoverable loss of tropical coral reefs locally). Large local population declines of wild species have already impacted human food sources and livelihoods (e.g., for Indigenous Arctic communities). Soft limits are currently being experienced in particular by individuals, households, cities and settlements along the coast and by small-scale farmers ( ''medium confidence'' ). As sea levels rise and extreme events intensify, coastal communities face limits due to financial, institutional and socioeconomic constraints and a short timeline for adaptation implementation, reducing the efficacy of coastal protection and accommodation approaches and resulting in loss of life and economic damages ( ''medium confidence'' ). { 2.4.2, 2.5.4, 2.6.1, 3.4.2, 3.4.3, CCP1, CCP2, CCP6, 4.7.4, Box 4.2, 6.4.4, 11.3.1, 11.3.2, 11.3.4, 11.3.5, 12.5.1, 13.3.1, 13.4.1, 13.10.2, 15.5.4, 15.5.6, 16.4.2, 16.4.3, [https://www.ipcc.ch/chapter/ts#CCP5.2.7 CCP5.2.7] , [https://www.ipcc.ch/chapter/ts#CCP5.3.2 CCP5.3.2] }

'''TS.D.2.3 Limits to adaptation will be reached in more systems, including, for example, coastal communities, water security, agricultural production and human health, as global warming increases (''' '''''medium confidence''''' ''').''' Hard limits beginning at 1.5°C are also projected for coastal communities reliant on nature-based coastal protection ( ''medium confidence'' ). Adaptation to address the risks of heat stress, heat mortality and reduced capacities for outdoor work for humans face soft and hard limits across regions that become significantly more severe at 1.5°C and are particularly relevant for regions with warm climates ( ''high confidence'' ). Beginning at 3°C, hard limits are projected for water management measures, leading to decreased water quality and availability, negative impacts on health and well-being, economic losses in water and energy-dependent sectors and potential migration of communities ( ''medium confidence'' ). Soft and hard limits for agricultural production are related to water availability and the uptake and effectiveness of climate resilient crops, which are constrained by socioeconomic and political challenges ( ''medium confidence'' ). In terms of settlements, limits to adaptation are often most pronounced in smaller and rapidly growing towns and cities, including those without dedicated local government ( ''medium confidence'' ). At the same time, legacy infrastructure in large and mega cities, designed without taking climate change risk into account, constrains innovation, leading to stranded assets and with increasing numbers of people unable to avoid harm, including heat stress and flooding, without transformative adaptation ( ''medium confidence'' ). { 2.4.2, 3.4.2, 3.5.5, 3.6.3, 4.7.4, Box 4.2, Box 4.3, 4.7.2, 4.7.3, 6.4.3, 6.4.5, 6.4.5, 6.4.5, Figure 6.4, 16.4.2, 16.4.3, 3.4.3, 11.3.1, 11.3.2 11.3.4, 11.3.5, 11.3.6, 12.5.1, 12.5.2, 12.5.3, 13.10.2, Box 11.6, Table 14.6, 15.3.3, 15.3.4, 15.5.4, 16.4.2, 16.4.3, CCP2, CCB ILLNESS, CCB SLR }

'''TS.D.2.4 Across regions and sectors, the most significant determinants of soft limits are financial, governance, institutional and policy constraints (''' '''''high confidence''''' ''').''' The ability of actors to address these socioeconomic constraints largely influences whether additional adaptation can be implemented and prevent soft limits from becoming hard limits. Global and regional evidence shows that climate impacts may limit the availability of financial resources, stunt national economic growth, result in higher levels of losses and damage and thereby increase financial constraints ( ''medium evidence'' ). Information, awareness and technological constraints are also high in multiple regions ( ''high confidence'' ). For example, awareness of anthropogenic climate change ranges between 23% and 66% of people across 33 African countries, with low climate literacy limiting potential for transformative adaptation ( ''medium confidence'' ). '''(''' Figure TS.7 VULNERABILITY) { 2.3.1, 2.3.2, 2.5.1, 2.6.8, 3.6.3, 4.7.4, 6.4.4, 9.3.1, 9.4.1, 9.4.5, 12.8, 13.11.1, 14.7.2, 15.6.1, 15.6.3, 16.4.2, 16.4.3, CCP2, [https://www.ipcc.ch/chapter/ts#CCP5.4.1 CCP5.4.1] , [https://www.ipcc.ch/chapter/ts#CCP7.5 CCP7.5] , [https://www.ipcc.ch/chapter/ts#CCP7.6 CCP7.6] , CCB EXTREMES }

'''TS.D.2.5 The potential for reaching adaptation limits fundamentally depends on emissions reductions and mitigating global warming (''' '''''high confidence''''' ''')''' . Under all emissions scenarios, climate change reduces capacity for adaptive responses and limits choices and opportunities for sustainable development. The ability of actors to overcome socioeconomic constraints determines whether additional adaptation can be implemented and prevent soft limits from becoming hard limits ( ''medium confidence'' ). Above 1.5°C of warming, limits to adaptation are reported for human and natural systems, including coral reefs ( ''high confidence'' ), regional water availability ( ''medium'' ''evidence'' '', high agreement'' ) and outdoor labour and existing tourism-related activities . { 1.1.3, 1.5.1, 2.6.0, 2.6.1, 2.6.2, 2.6.3, 2.6.4, 2.6.5, 2.6.8, 3.6.3, 3.6.5, 4.7.1, 4.7.2, Box 4.3, 3.5.2, 3.6.2, 3.6.2, 13.10.2, 14.5.7, 14.5.8, 15.3.3, 15.3.4, Box 15.1, 16.4, 16.5, 16.6, [https://www.ipcc.ch/chapter/ts#CCP5.3.2 CCP5.3.2] }

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