Editing IPCC:AR6/WGII/Chapter-16 (section)

===== Limits to adaptation across natural and human systems =====

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'''There is increasing evidence on limits to adaptation which result from the interaction of adaptation constraints and can be differentiated into soft and hard limits (''' '''''high confidence''''' ''').''' Soft limits may change over time as additional adaptation options become available. Hard limits will not change over time as no additional adaptive actions are possible. Evidence focuses on constraints that may lead to limits at some point of the adaptation process, with less information on how limits may be related to different levels of socioeconomic or climatic change ( ''high confidence'' ). {16.4.1, 16.4.2, 16.4.3}

'''Limits to adaptation have been identified for terrestrial and aquatic species and ecosystems, coastal communities, water security, agricultural production, and human health and heat (''' '''''high confidence''''' ''').''' Beginning at 1.5°C, autonomous and evolutionary adaptation responses by terrestrial and aquatic species and ecosystems face hard limits, resulting in biodiversity decline, species extinction and loss of related livelihoods ( ''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'' ). Adaptation to address risks of heat stress, heat mortality and reduced capacities for outdoor work for humans face soft and hard limits across regions beginning at 1.5°C, and are particularly relevant for regions with warm climates ( ''high confidence'' ). {16.4.2, 16.4.3}

'''Soft limits are currently being experienced by individuals and households along the coast and by small-scale farmers (''' '''''medium confidence''''' ''').''' As sea levels rise and extreme events intensify, coastal communities face soft limits due to financial, institutional and socioeconomic constraints reducing the efficacy of coastal protection and accommodation approaches and resulting in loss of life and economic damages ( ''medium confidence'' ). {16.4.2, 16.4.3}

'''Hard limits for coastal communities reliant on nature-based coastal protection will be experienced beginning at 1.5°C (''' '''''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'' ). {16.4.2, 16.4.3}

'''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 overcome these socioeconomic constraints largely influence whether additional adaptation is able to be implemented and prevent soft limits from becoming hard. While the rate, extent and timing of climate hazards largely determine hard limits of biophysical systems, these factors appear to be less influential in determining soft limits for human systems ( ''medium confidence'' ). {16.4.2, 16.4.3}

'''Financial constraints are important determinants of limits to adaptation, particularly in low-to-middle-income countries (''' '''''high confidence''''' ''').''' Impacts of climate change may increase financial constraints ( ''high confidence'' ) and contribute to soft limits to adaptation being reached ( ''medium confidence'' ). 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 damages and thereby increase financial constraints. {16.4.3.2, 16.4.3.3}

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