Editing IPCC:AR6/WGII/Chapter-14 (section)

== Executive Summary ==

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'''Since AR5, climate-change impacts have become more frequent, intense and have affected many millions of people from every region and sector across North America (Canada, USA and Mexico). Accelerating climate-change hazards pose significant risks to the well-being of North American populations and the natural, managed and human systems on which they depend (''' '''''high confidence''''' [[#footnote-020|1]] '''). Addressing these risks has been made more urgent by delays due to misinformation about climate science that has sowed uncertainty and impeded recognition of risk (''' '''''high confidence''''' '''). {14.2, 14.3}'''

'''Without limiting warming to 1.5''' ° '''C, key risks to North America are expected to intensify rapidly by mid-century (''' '''''high confidence''''' '''). These risks will result in irreversible changes to ecosystems, mounting damages to infrastructure and housing, stress on economic sectors, disruption of livelihoods, and issues with mental and physical health, leisure and safety. Immediate, widespread and coordinated implementation of adaptation measures aimed at reducing risks and focused on equity have the greatest potential to maintain and improve the quality of life for North Americans, ensure sustainable livelihoods and protect the long-term biodiversity, and ecological and economic productivity, in North America (''' '''''high confidence''''' '''). Enhanced sharing of resources and tools for adaptation across economic, social, cultural and national entities enables more effective short- and long-term responses to climate change. {14.2, 14.4, 14.5, 14.6, 14.7}'''

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===== Past and Current Impacts and Adaptation =====

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'''Over the past 20 years, climate-change impacts across North America have become more frequent, intense and affect more of the population (''' '''''high confidence''''' ''').''' Despite scientific certainty of the anthropogenic influence on climate change, misinformation and politicisation of climate-change science has created polarisation in public and policy domains in North America, particularly in the USA, limiting climate action ( ''high confidence'' ). Vested interests have generated rhetoric and misinformation that undermines climate science and disregards risk and urgency ( ''medium confidence'' ). Resultant public misperception of climate risks and polarised public support for climate actions is delaying urgent adaptation planning and implementation ( ''high confidence'' ). Drawing upon Indigenous knowledge, enhancing communication and outreach and undertaking collaborations to co-create equitable solutions are critical for successful climate action. {Box 14.1, 14.3, 14.7}

'''Climate change has negatively impacted human health and well-being in North America (''' '''''very high confidence''''' ''').''' High temperatures have increased mortality and morbidity ( ''very high confidence'' ), with impacts that vary by age, gender, location and socioeconomic conditions ( ''very high confidence'' ). Changes in temperature and precipitation have increased risk of vector-borne ( ''very high confidence'' ), water-borne ( ''high confidence'' ) and food-borne diseases ( ''very high confidence'' ). Changes in climate and extreme events have been linked to wide-ranging negative mental health outcomes ( ''high confidence'' ). The loss of access to marine and terrestrial sources of protein has impacted the nutrition of subsistence-dependent communities across North America ( ''high confidence'' ). Climate change has increased the extent of warmer and drier conditions favourable for wildfires ( ''medium confidence'' ) that increase respiratory distress from smoke ( ''very high confidence'' ). {14.5.2, 14.5.6, Box 14.2}

'''North American food production is increasingly affected by climate change (''' '''''high confidence''''' '''), with immediate impacts on the food and nutritional security of Indigenous Peoples.''' Climate change and extreme weather events have impacted North American agroecosystems ( ''high confidence'' ), with crop-specific effects that vary in direction and magnitude by event and location. Climate change has generally reduced agricultural productivity by 12.5% since 1961, with progressively greater losses moving south from Canada to Mexico and in drought-prone rain-fed systems ( ''high confidence'' ) while favourable conditions increased yields of maize, soybeans in regions like the USA Great Plains. Loss of availability and access to marine and terrestrial sources of protein has impaired food security and nutrition of subsistence-dependent Indigenous Peoples across North America ( ''high confidence'' ). Climate change has impacted aquaculture ( ''high confidence'' ) and induced rapid redistribution of species ( ''very high confidence'' ), and population declines of multiple key fisheries ( ''high confidence'' ). {14.5.4, 14.5.6, 14.7}

'''Climate change has impaired North American freshwater resources and reduced supply security (''' '''''high confidence''''' ''').''' Reduced snowpack and earlier runoff ( ''high confidence'' ) have adversely affected aquatic ecosystems and freshwater availability for human uses ( ''medium confidence'' ). Recent severe droughts, floods and harmful algal and pathogen events have caused harm to large populations and key economic sectors ( ''high confidence'' ). Heavy exploitation of limited water supplies, especially in the western USA and northern Mexico, and deteriorating freshwater management infrastructure, have heightened the risks ( ''high confidence'' ). Effective examples of freshwater resource adaptation planning are already underway, but coordinated adaptation implementation across multiple conflicting interests and users is complicated and time-consuming ( ''high confidence'' ). {14.5.1, 14.5.2, 14.5.3}

'''Extreme events and climate hazards are adversely affecting economic activities across North America and have disrupted supply chain infrastructure and trade (''' '''''high confidence''''' ''')''' '''''.''''' Larger losses and adaptation costs are observed for sectors with high climate exposures, including tourism, fisheries, and agriculture ( ''high confidence'' ) and outdoor labour ( ''medium confidence)'' . Disaster planning and spending, insurance, markets, and individual and household-level adaptation have acted to moderate effects to date ( ''medium confidence)'' . Entrenched socioeconomic vulnerabilities have amplified climate impacts for marginalised groups, including Indigenous Peoples, due to the impact of colonialism and discrimination ( ''medium confidence'' ). {14.5.4, 14.5.5, 14.5.6, 14.5.7, 14.5.9, Box 14.1, Box 14.5, Box 14.6}

'''North American cities and settlements have been affected by increasing severity and frequency of climate hazards and extreme events (''' '''''high confidence''''' '''), which has contributed to infrastructure damage, livelihood losses, damage to heritage resources and safety concerns.''' Impacts are particularly apparent for Indigenous Peoples for whom culture, identity, commerce, health and well-being are closely connected to a resilient environment ( ''very high confidence'' ). Higher temperatures have been associated with violent and property crime in the USA ( ''medium confidence'' ), yet the overall effects of climate change on crime and violence in North America are not well understood. {14.4, 14.5.5, 14.5.6, 14.5.8, 14.5.9, Box 14.1}

'''Terrestrial, marine and freshwater ecosystems are being profoundly altered by climate change across North America (''' '''''very high confidence''''' ''').''' Rising air, water, ocean and ground temperatures have restructured ecosystems and contributed to the redistribution ( ''very high confidence'' ) and mortality ( ''high confidence'' ) of fish, bird and mammal species. Extreme heat and precipitation trends on land have increased vegetation stress and mortality, reduced soil quality and altered ecosystem processes including carbon and freshwater cycling ( ''very high confidence'' ). Warm and dry conditions associated with climate change have led to tree die-offs ( ''high confidence'' ) and increased prevalence of catastrophic wildfire ( ''medium confidence'' ) with an increase in the size of severely burned areas in western North America ( ''medium confidence'' ). Nature-based Solutions (NbS) and ecosystem-based management have been effective adaptation approaches in the past but are increasingly exceeded by climate extremes ''(medium confidence'' ). {14.5.1–3, Box 14.7}

'''Climate-driven changes are particularly pronounced within Arctic ecosystems and are unprecedented based on observations from multiple knowledge systems (''' '''''very high confidence''''' ''').''' Climate change has contributed to cascading environmental and sociocultural impacts in the Arctic ( ''high to very high confidence'' ) that have adversely, and often irreversibly, altered Northern livelihoods, cultural activities, essential services, health, food and nutritional security, community connectivity and well-being ( ''high confidence'' ). {14.5.2, 14.5.4, 14.5.6, 14.5.7, 14.5.8, Box 14.6}

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===== Future Risks and Adaptation =====

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'''Climate hazards are projected to intensify further across North America (''' '''''very high confidence''''' ''').''' Heatwaves over land and in the ocean, as well as wildfire activity, will intensify; subarctic snowpack, glacial mass and sea ice will decline ( ''virtually certain'' ); and sea level rise will increase at geographically differential rates ( ''virtually certain'' ). Humidity-enhanced heat stress, aridification and extreme precipitation events that lead to severe flooding, erosion, debris flows and ultimately loss of ecosystem function, life and property are projected to intensify ( ''high confidence'' ). {14.2}

'''Health risks are projected to increase this century under all future emissions scenarios (''' '''''very high confidence''''' '''), but the magnitude and severity of impacts depends on the implementation and effectiveness of adaptation strategies (''' '''''very high confidence''''' ''').''' Warming is projected to increase heat-related mortality ( ''very high confidence'' ) and morbidity ( ''medium confidence'' ). Vector-borne disease transmission, water-borne disease risks, food safety risks and mental health outcomes are projected to increase this century ( ''high confidence'' ). Available adaptation options will be less effective or unable to protect human health under high-emission scenarios ( ''high confidence'' ). {14.5.6, Box 14.2}

'''Climate-induced redistribution and declines in North American food production are a risk to future food and nutritional security (''' '''''very high confidence''''' ''')''' '''''.''''' Climate change will continue to shift North American agricultural and fishery suitability ranges ( ''high confidence'' ) and intensify production losses of key crops ( ''high confidence'' ), livestock ( ''medium confidence'' ), fisheries ( ''high confidence'' ) and aquaculture products ( ''medium confidence'' ). In the absence of mitigation, incremental adaptation measures may not be sufficient to address rapidly changing conditions and extreme events, increasing the need for cross-sectoral coordination in implementation of mitigation and adaptation measures ( ''high confidence'' ). Combining sustainable intensification, approaches based on Indigenous knowledge and local knowledge, and ecosystem-based methods with inclusive and self-determined decision making, will result in more equitable food and nutritional security ( ''high confidence'' ). {14.5.1–4, 14.5.6, 14.7, Cross-Chapter Box INDIG in Chapter 18, Cross-Chapter Box MOVING PLATE in Chapter 5}

'''Escalating climate-change impacts on marine, freshwater and terrestrial ecosystems (''' '''''high confidence''''' ''') will alter ecological processes (''' '''''high confidence''''' ''') and amplify other anthropogenic threats to protected and iconic species and habitats (''' '''''high confidence''''' ''').''' Hotter droughts and progressive loss of seasonal water storage in snow and ice will tend to reduce summer season stream flows in much of western North America, while population growth, extensive irrigated agriculture and the needs of threatened and endangered aquatic species will continue to place high demands on those flows ( ''high confidence'' ). {14.2.2, 14.5.1, 14.5.2, 14.5.3, 14.5.4, 14.5.6, Box 14.7.1}

'''Market and non-market economic damages are projected to increase to the end of the century from climate impacts (''' '''''high confidence''''' ''').''' Estimates for the costs of climate inaction are substantial across economic sectors, infrastructure, human health and disaster management. Hard limits to adaptation may be reached for outdoor labour ( ''medium confidence'' ) and nature-based winter tourism activities ( ''very high confidence'' ). At higher levels of warming, climate impacts may pose systemic risks to financial markets through impacts on transportation systems, supply chains and major infrastructure, as well as global-scale challenges to trade ( ''medium confidence'' ) ''.'' {14.2.2, 14.5.4, 14.5.8, 14.5.7, 14.5.9, 14.5.5, Box 14.5, Box 14.6}

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===== Solution Space and Governance =====

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'''Self-determination for Indigenous Peoples is critical for effective adaptation in Indigenous communities (''' '''''very high confidence''''' ''').''' Throughout North America, Indigenous Peoples are actively addressing the compound impacts of climate change, and historical and ongoing forms of colonialism ( ''very high confidence'' ). Indigenous knowledge underpins successful understanding of, responses to, and governance of climate-change risks. Western scientific practices and technology may not be sufficient in addressing future natural resource management challenges. Supporting Indigenous self-determination, recognising Indigenous Peoples’ Rights, and supporting adaptation underpinned by Indigenous knowledge are critical to reducing climate-change risks to achieve adaptation success ( ''very high confidence'' ). {14.7.3, Box 14.1}

'''Equitable, inclusive and participatory approaches that integrate climate-impact projections into near- and long-term decision making reduce future risks (''' '''''high confidence''''' ''').''' Government and private investment are increasingly focusing on early warning and rapid response systems, climate and ecological forecasting tools, and integrated climate scenario planning methods. Widespread adoption of these practices and tools for infrastructure planning, disaster risk reduction, ecosystem management, budgeting practices, insurance, and climate risk reporting supports planning for a future with more climate risks ( ''high confidence'' ). Increased capacity to support the equitable resolution of existing and emerging resource disputes (local to international) will reduce climate impacts on livelihoods and improve the effectiveness of resource management ( ''high confidence'' ). {14.5.5, 14.5.10, 14.7}

'''Near- and long-term adaptation planning, implementation and coordination across sectors and jurisdictions supports equitable and effective climate solutions (''' '''''high confidence''''' ''').''' Recognition of the need for adaptation across North America is increasing, but action has been mostly gradual, incremental and reactive ( ''high confidence'' ). Current practices will be increasingly insufficient without coordination and integration of efforts through equitable policy focused on modifying land-use impacts, consumption patterns, economic activities and emphasising NbS ( ''high confidence'' ). Transformational, long-term adaptation action that reduces risk and increases resilience can address rapidly escalating impacts in the long-term, especially if coupled with moderate to high mitigation measures ( ''high confidence'' ). {14.7}

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