Editing IPCC:AR6/WGII/Chapter-7 (section)

== Executive Summary ==

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'''Climate-related illnesses, premature deaths, malnutrition in all its forms, and threats to mental health and well-being are increasing''' '''''(''''' ''very high confidence'' [[#footnote-001|1]] ''''').''''' '''Climate hazards are a growing driver of involuntary migration and displacement (''' ''high confidence'' ''') and are a contributing factor to violent conflict''' '''''(''''' ''high confidence'' ''''').''''' These impacts are often inter-connected, are unevenly distributed across and within societies, and will continue to be experienced inequitably due to differences in exposure and vulnerability ( ''very high confidence'' ). Cascading and compounding risks affecting health due to extreme weather events have been observed in all inhabited regions, and risks are expected to increase with further warming ( ''very high confidence'' ) {7.1.3, 7.1.4; Cross-Chapter Box COVID in Chapter 7; 7.2.1, 7.2.2, 7.2.3, 7.2.4, 7.3.1, 7.3.2, 7.3.3, 7.4.1, 7.4.4; Cross-Chapter Box HEALTH in Chapter 7; Cross-Chapter Box ILLNESS in Chapter 2} .

'''Since AR5, new evidence and awareness of current impacts and projected risks of climate change on health, well-being, migration and conflict have emerged, including greater evidence of the detrimental impacts of climate change on mental health (''' ''very high confidence'' ''').''' New international agreements were reached on climate change (Paris Agreement), disaster risk reduction (DRR) (Sendai Agreement), sustainable development (the Sustainable Development Goals (SDGs)), urbanisation (The New Urban Agenda), migration (Global Compact for Safe, Orderly and Regular Migration) and refugees (Global Compact on Refugees) that, if achieved, would reduce the impacts of climate change on health, well-being, migration and conflict ( ''very high confidence'' ). However, the challenges with implementing these agreements are highlighted by the coronavirus disease 2019 (COVID-19) pandemic, which exposed systemic weaknesses at community, national and international levels in the ability of societies to anticipate and respond to global risks ''(high confidence)'' . Incremental changes in policies and strategies have proven insufficient to reduce climate-related risks to health, well-being, migration and conflict, highlighting the value of more integrated approaches and frameworks for solutions across systems and sectors that are embodied in these new international agreements ''(high confidence)'' {7.1.3, 7.2.1, 7.4.1, 7.4.2, 7.4.3, 7.4.6; Cross-Chapter Box COVID in Chapter 7} .

'''With proactive, timely and effective adaptation, many risks for human health and well-being could be reduced and some potentially avoided (''' ''very high confidence'' ''').''' A significant adaptation gap exists for human health and well-being and for responses to disaster risks ( ''very high confidence'' ). Nationally Determined Contributions (NDCs) to the Paris Agreement from low- and middle-income countries identify health as a priority concern. National planning on health and climate change is advancing, but the comprehensiveness of strategies and plans need to be strengthened, and implementing action on key health and climate change priorities remains challenging ''(high confidence)'' . Multi-sectoral collaboration on health and climate change policy is evident, with uneven progress, and financial support for health adaptation is only 0.5% of dispersed multi-lateral climate finance projects ''(high confidence)'' . This level of investment is insufficient to protect population health and health systems from most climate-sensitive health risks ( ''very high confidence'' ) {7.4.1, 7.4.2, 7.4.3} .

'''Climate resilient development has a strong potential to generate substantial co-benefits for health and well-being and to reduce risks of involuntary displacement and conflict (''' ''very high confidence'' ''').''' Sustainable and climate resilient development that decreases exposure, vulnerability and societal inequity and that increases timely and effective adaptation and mitigation more broadly, has the potential to reduce but not necessarily eliminate climate change impacts on health, well-being, involuntary migration and conflict ''(high confidence)'' . This development includes greenhouse gas (GHG) emission reductions through clean energy and transport; climate-resilient urban planning; sustainable food systems that lead to healthier diets; universal access to healthcare and social protection systems; wide-scale, proactive adaptive capacity building for climate change; and achievement of the SDGs ''(very high confidence)'' . Meeting the objectives of the Global Compact for Safe, Orderly, and Regular Migration and building inclusive and integrative approaches to climate-resilient peace would help prevent health risks related to migration and conflict ( ''high agreement, medium evidence'' ). The net global financial gains from these co-benefits to health and well-being, including avoided hospitalisations, morbidity and premature deaths, exceed the financial costs of mitigation ( ''high confidence'' ). As an example of co-benefits, the financial value of health benefits from improved air quality alone is projected to be greater than the costs of meeting the goals of the Paris Agreement ''(high confidence)'' . All pathways to climate resilient development, including those for the health and healthcare systems, involve balancing complex synergies and trade-offs between development pathways and the options that underpin climate mitigation and adaptation pathways ( ''very high confidence'' ) {7.4.6; Cross-Chapter Box HEALTH in Chapter 7; Cross-Chapter Box MIGRATE in Chapter 7} .

'''Key transformations are needed to facilitate climate resilient development pathways (CRDPs) for health, well-being, migration and conflict avoidance''' '''''(''''' ''high confidence'' ''''').''''' '''The transformational changes will be more effective if they are responsive to regional, local and Indigenous knowledge and consider the many dimensions of vulnerability, including those that are gender- and age-specific''' '''''(''''' ''high confidence'' ''''')''''' '''.''' A key pathway towards climate resilience in the health sector is universal access to primary healthcare, including mental healthcare ( ''high confidence'' ). Investments in other sectors and systems that improve upon the social determinants of health have the potential to reduce vulnerability to climate-related health risks ( ''high confidence'' ). Links between climate risks, adaptation, migration and labour markets highlight the value of providing better mobility options as part of transformative change ''(medium confidence)'' . Strong governance and gender-sensitive approaches to natural resource management can reduce the risk of inter-group conflict in climate-disrupted areas ''(medium confidence)'' {7.4.6; Cross-Chapter Box COVID in Chapter 7; Cross-Chapter Box HEALTH in Chapter 7; Cross-Chapter Box GENDER in Chapter 18; Cross-Chapter Box INDIG in Chapter 18; Cross-Chapter Box MIGRATE in Chapter 7} .

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===== Observed Impacts =====

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'''Climate hazards are increasingly contributing to a growing number of adverse health outcomes (including communicable and non-communicable diseases (NCDs)) in multiple geographical areas''' '''''(''''' ''very high confidence'' ''''')''''' '''. The net impacts are largely negative at all scales''' '''''(''''' ''very high confidence'' '''''),''''' '''and there are very few examples of beneficial outcomes from climate change at any scale''' '''''(''''' ''high confidence)'' . While malaria incidence has declined globally due to non-climatic socioeconomic factors and health system responses, a shift to higher altitudes has been observed as the climate warms ''(very high confidence)'' . Climate variability and change (including temperature, relative humidity and rainfall) and population mobility are significantly and positively associated with observed increases in dengue globally; chikungunya virus in Asia, Latin America, North America and Europe ''(high confidence)'' ; Lyme disease vector ''Ixodes scapularis'' in North America ''(high confidence)'' ; and Lyme disease and tick-borne encephalitis vector ''Ixodes ricinus'' in Europe ''(medium confidence)'' . Higher temperatures ( ''very high confidence'' ), heavy rainfall events ''(high confidence)'' and flooding ''(medium confidence)'' are associated with an increase of diarrhoeal diseases in affected regions, including cholera ''(very high confidence)'' , other gastrointestinal infections ''(high confidence)'' and food-borne diseases due to ''Salmonella'' and ''Campylobacter (medium confidence).'' Floods have led to increases in vector- and waterborne diseases and to disturbances of public health services ''(high confidence)'' . Climate extremes increase the risks of several types of respiratory tract infections ''(high confidence)'' . Climate-related extreme events such as wildfires, storms and floods are followed by increased rates of mental illness in exposed populations ( ''very high confidence'' ) {7.2.1, 7.2.2, 7.2.3, 7.2.4, 7.2.5, 7.2.6} .

'''Several chronic, non-communicable respiratory diseases are climate-sensitive based on their exposure pathways (e.g., heat, cold, dust, small particulates, ozone, fire smoke and allergens)''' '''''(''''' ''high confidence'' '''''),''''' '''although climate change is not the dominant driver in all cases.''' Worldwide, rates of adverse health impacts associated with small particulate matter (PM) exposure have decreased steadily due to decreasing primary emissions ''(very high confidence)'' , while rates of adverse health impacts from ozone air pollution exposure have increased ''(very high confidence).'' Exposure to wildland fires and associated smoke has increased in several regions ( ''very high confidence'' ). Spring pollen season start dates in northern mid-latitudes are occurring earlier due to climate change, increasing the risks of allergic respiratory diseases ''(high confidence)'' {7.2.3.2} .

'''Heat is a growing health risk due to burgeoning urbanisation, an increase in high temperature extremes and demographic changes in countries with aging populations''' '''''(''''' ''very high confidence'' ''''')''''' . Potential hours of work lost due to heat has increased significantly over the past two decades ( ''high confidence'' ). Some regions are already experiencing heat stress conditions at or approaching the upper limits of labour productivity ''(high confidence).'' A significant proportion of warm-season heat-related mortality in temperate regions is linked to observed anthropogenic climate change ( ''medium confidence'' ) but greater evidence is required for tropical regions. For some heatwave events over the last two decades, associated health impacts can be at least partially attributed to observed climate change ( ''high confidence'' ). Extreme heat has negative impacts on mental health, well-being, life satisfaction, happiness, cognitive performance and aggression ( ''medium confidence'' ) {7.2.4.1, 7.2.4.5} .

'''Climate variability and change contribute to food insecurity, which can lead to malnutrition, including undernutrition, overweight and obesity, and to disease susceptibility in low- and middle-income countries (''' ''high confidence'' ''').''' Populations exposed to extreme weather and climate events may consume inadequate or insufficient food, leading to malnutrition and increasing the risk of disease ( ''high confidence'' ). Children and pregnant women experience disproportionately greater adverse nutrition and health impacts ''(high confidence)'' . Climatic influences on nutrition are strongly mediated by socioeconomic factors ( ''very high confidence'' ) {7.2.4.4, 7.3.1} .

'''Extreme climate events act as both direct drivers (e.g., destruction of homes by tropical cyclones) and as indirect drivers (e.g., rural income losses during prolonged droughts) of involuntary migration and displacement''' '''''(''''' ''very high confidence'' ''''').''''' Most documented examples of climate-related displacement occur within national boundaries, with international movements occurring primarily within regions, particularly between countries with contiguous borders ''(high confidence)'' . Global statistics collected since 2008 by the Internal Displacement Monitoring Centre (IDMC) show an annual average of over 20 million people internally displaced by weather-related extreme events, with storms and floods the most common drivers ''(high confidence).'' The largest absolute number of people displaced by extreme weather each year occurs in Asia (South, Southeast and East), followed by sub-Saharan Africa, but small island states in the Caribbean and South Pacific are disproportionately affected relative to their small population size ( ''high confidence'' ). Immobility in the context of climate risks can reflect vulnerability and lack of agency but can also be a deliberate choice of people to maintain livelihoods, economic considerations and social and cultural attachments to place ( ''high confidence'' ) {7.2.6; Cross-Chapter Box MIGRATE in Chapter 7} .

'''Climate hazards have affected armed conflict within countries (''' ''medium confidence'' '''), but the influence of climate is small compared to socioeconomic, political and cultural factors''' '''''(''''' ''high confidence'' ''''').''''' Climate increases conflict risk by undermining food and water security, income and livelihoods in situations where there are large populations, weather-sensitive economic activities, weak institutions and high levels of poverty and inequality ''(high confidence).'' In urban areas, food and water insecurity and inequitable access to services has been associated with civil unrest where there are weak institutions ''(medium confidence)'' . Climate hazards are associated with increased violence against women, girls and vulnerable groups, and the experience of armed conflict is gendered ''(medium confidence)'' . Adaptation and mitigation projects implemented without consideration of local social dynamics have exacerbated non-violent conflict ''(medium confidence)'' {7.2.7} .

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===== Projected Risks and Vulnerabilities =====

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'''A significant increase in ill health and premature deaths from climate-sensitive diseases and conditions is projected due to climate change''' '''''(''''' ''high confidence'' ''''')''''' '''.''' An excess of 250,000 deaths yr –1 by 2050 attributable to climate change is projected due to heat, undernutrition, malaria and diarrhoeal disease, with more than half of this excess mortality projected for Africa (compared to a 1961–1991 baseline period for a mid-range emissions scenario) ''(high confidence)'' . Risks for heat-related morbidity and mortality, ozone-related mortality, malaria, diseases carried by ''Aedes'' sp. mosquitoes, Lyme disease and West Nile fever, as well as the temperatures at which risk transitions occur (i.e. from moderate to high to very high), are contingent on future development pathways ''(high confidence)'' {7.3.1} .

'''Climate change is projected to significantly increase population exposure to heatwaves (''' ''very high confidence'' ''') and heat-related morbidity and mortality''' '''''(''''' ''high confidence'' ''''').''''' Models suggest exposure increases 16 times under Representative Concentration Pathway (RCP)4.5 and 36 times under RCP8.5, with the impact of warming amplified under development pathways that do not foster sustainable development ''.'' Globally, the impact of projected climate change on temperature-related mortality is expected to be a net increase under RCP4.5 to RCP8.5, even with adaptation ( ''high confidence).'' Heat related cardiovascular disease mortality is projected to increase by the end of this century ''(high confidence).'' Strong geographical differences in heat-related mortality are projected to emerge later this century, mainly driven by population growth and aging in regions with tropical and subtropical climates ''(very high confidence)'' {7.3.1} .

'''The burdens of several climate-sensitive food-borne, waterborne, and vector-borne diseases (VBDs) are projected to increase under climate change, assuming no additional adaptation''' '''''(''''' ''very high confidence'' ''''')''''' . The distribution and intensity of transmission of malaria is expected to decrease in some areas and increase in others, with increases projected mainly along the current edges of its geographic distribution in endemic areas of sub-Saharan Africa, Asia and South America ''(high confidence)'' . Dengue risk will increase, with a larger spatio-temporal distribution in Asia, Europe and sub-Saharan Africa under RCP6.0 and RCP8.5, potentially putting another 2.25 billion people at risk ''(high confidence).'' Higher incidence rates are projected for Lyme disease in the Northern Hemisphere ''(high confidence)'' and for transmission of ''Schistosoma mansoni'' in eastern Africa ''(high confidence)'' {7.3.1; Cross-Chapter Box ILLNESS in Chapter 2} .

'''Increasing atmospheric concentrations of carbon dioxide and climate change are projected to increase diet-related risk factors and related non-communicable diseasess globally and increase undernutrition, stunting and related childhood mortality particularly in Africa and Asia, with outcomes depending on the extent of mitigation and adaptation''' '''''(''''' ''high confidence'' ''''')''''' '''.''' These projected changes are expected to slow progress towards eradication of child undernutrition and malnutrition ''(high confidence)'' . Higher atmospheric concentrations of carbon dioxide reduce the nutritional quality of wheat, rice and other major crops, potentially affecting millions of people at a doubling of carbon dioxide ''(very high confidence)'' {7.3.1} .

'''Climate change is expected to have adverse impacts on well-being and to further threaten mental health (''' ''very high confidence'' ''').''' Children and adolescents, particularly girls, elderly people, and people with existing mental, physical and medical challenges are particularly at risk. Mental health impacts are expected to arise from exposure to high temperatures, extreme weather events, displacement, malnutrition, conflict, climate-related economic and social losses, and anxiety and distress associated with worry about climate change ( ''very high confidence'' ) {7.3.1.11} .

'''Future climate-related migration is expected to vary by region and over time, according to future climatic drivers, patterns of population growth, adaptive capacity of exposed populations and international development and migration policies (''' ''high confidence'' ''').''' The wide range of potential outcomes is reflected in model projections of population displacements by 2050 in Latin America, sub-Saharan Africa and south Asia due to climate change, which vary from 31 million to 143 million people, depending on assumptions about future GHG emissions and socioeconomic development trajectories ''(high confidence)'' . With every additional one degree Celsius of warming, the global risks of involuntary displacement due to flood events are projected to rise by approximately 50% ''(high confidence)'' . High emissions/low development scenarios raise the potential for higher levels of migration and involuntary displacement ''(high confidence)'' and increase the need for planned relocations and support for people exposed to climate extremes but lacking the means to move ( ''high confidence'' ) {7.3.2; Cross-Chapter Box MIGRATE in Chapter 7} .

'''Climate change may increase susceptibility to violent conflict, primarily intra-state conflicts, by strengthening climate-sensitive drivers of conflict''' ''(medium confidence)'' . Future violent conflict risk is highly mediated by socioeconomic development trajectories ( ''high confidence'' ) and so trajectories that prioritise economic growth, political rights and sustainability are associated with lower conflict risk ''(medium confidence)'' . Future climate change may exceed adaptation limits and generate new causal pathways not observed under current climate variability ''(medium confidence).'' Economic shocks are not included in many models of conflict risks currently used, and some projections do not incorporate known socioeconomic predictors of conflict ''(medium confidence)'' . As such, future increases in conflict-related deaths with climate change have been estimated, but results are inconclusive ''(medium confidence)'' .

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===== Solutions =====

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'''Since AR5, the value of cross-sectoral collaboration to advance sustainable development has been more widely recognised, but despite acknowledgement of the importance of health adaptation as a key component, action has been slow''' '''''(''''' ''high confidence).'' Building climate-resilient health systems will require multi-sectoral, multi-system and collaborative efforts at all governance scales ( ''very high confidence'' ) (Sections 7.4.1, 7.4.2). Globally, health systems are poorly resourced in general, and their capacity to respond to climate change is weak, with mental health support being particularly inadequate ( ''very high confidence'' ). The health sectors of some countries have focused on implementing incremental changes to policies and measures to fill the adaptation gap ( ''very high confidence'' ). As the likelihood of dangerous risks to human health continue to increase, there is greater need for transformational changes to health and other systems ( ''very high confidence'' ). This highlights an urgent and immediate need to address the wider interactions between environmental change, socioeconomic development and human health and well-being ''(high confidence)'' {7.4.1, 7.4.2, 7.4.3} .

'''Targeted investments in health and other systems, including multi-sectoral, integrated approaches to protect against key health risks can effectively increase resilience (''' ''high confidence'' ''').''' Increased investment in strengthening general health systems, along with targeted investments to enhance protection against specific climate-sensitive exposures (e.g., hazard early warning and response systems, and integrated vector control programmes for VBDs) will increase resilience if implemented to at least keep pace with climate change ''(high confidence).''

* The future effects of climate change on VBDs can be significantly offset through enhanced commitment to and implementation of integrated vector control management approaches, disease surveillance, early warning systems and vaccine development ''(very high confidence)'' (Sections 7.4.1, 7.4.2).
* Adaptation options for future climate risks associated with waterborne and food-borne diseasess include improving access to potable water, reducing exposure of water and sanitation systems to flooding and extreme weather events, and improved (including expanded) early warning systems ''(very high confidence)'' (Sections 7.4.1, 7.4.2).
* Adaptation options for future extreme heat risks include heat action plans (HAPs) that incorporate early warning and response systems for urban and non-urban settings; tried, tested and iteratively updated response strategies targeting both the general population and vulnerable groups such as older adults or outside workers; and effective stakeholder communication plans ( ''high confidence'' ). These short-term responses can be complemented by longer-term urban planning and design, including nature-based solutions (NbS) that mitigate urban heat island (UHI) effects ''(high confidence)'' (Sections 7.4.1, 7.4.2, 7.4.3).
* Adaptation options to reduce the future risks of malnutrition include access to healthy, affordable, diverse diets from sustainable food systems ''(high confidence)'' ; health services including maternal, child and reproductive health ( ''high confidence'' ); nutrition services, nutrition and shock sensitive social protection ( ''high confidence'' ); water, sanitation and early warning systems ''(high confidence)'' ; and risk reduction schemes such as insurance ''(medium confidence)'' ( [[#7.4.2.1|Section 7.4.2.1.3]] ).

'''The COVID-19 pandemic has demonstrated the value of coordinated and multi-sectoral planning, social protection systems, safety nets and other capacities in societies to cope with a range of shocks and stresses''' '''''(''''' ''high confidence'' ''''')''''' '''.''' The pandemic has posed a severe shock to many socioeconomic systems, resulting in substantial changes in vulnerability and exposure of people to climate risks ( ''high confidence'' ). The pandemic emphasises the inter-connected and compound nature of risks, vulnerabilities, and responses to emergencies that are simultaneously local and global ''(high confidence).'' Pathways to climate resilient development can be pursued simultaneously with recovering from the COVID-19 pandemic ''(high confidence).'' The COVID-19 pandemic has aggravated climate risks, demonstrated the global and local vulnerability to cascading shocks and illustrated the importance of integrated solutions that tackle ecosystem degradation and structural vulnerabilities in human societies ''(high confidence)'' {Cross-Chapter Box COVID in Chapter 7} .

'''Transitioning towards equitable, low-carbon societies has multiple benefits for health and well-being''' '''''(''''' ''very high confidence'' ''''')''''' '''.''' Benefits for health and well-being can be gained from wide-spread, equitable access to affordable renewable energy ( ''high confidence'' ); active transport (e.g., walking and cycling) ( ''high confidence'' ); green buildings and nature-based solutions, such as green and blue urban infrastructure ( ''high confidence'' ) '';'' and by transitioning to a low-carbon, well-being-oriented and equity-oriented economy consistent with the aims of the SDGs ''(high confidence)'' . Plant-rich diets consistent with international recommendations for healthy diets could contribute to lower GHG emissions while also generating health co-benefits, such as reducing ill health related to over-consumption of animal-based products ''(high confidence)'' {7.4.2; Cross-Chapter Box HEALTH in Chapter 7; 7.4.4} .

'''Reducing future risks of involuntary migration and displacement due to climate change is possible through cooperative international efforts to enhance institutional adaptive capacity and sustainable development''' '''''(''''' ''high confidence'' ''''').''''' Institutional and cross-sectoral efforts to build adaptive capacity, coupled with policies aimed at ensuring safe and orderly movements of people within and between states, can form part of the CRDPs that reduce future risks of climate-related involuntary migration, displacement and immobility ''(medium confidence)'' . In locations where permanent, government-assisted relocation becomes unavoidable, active involvement of local populations in planning and decision-making increases the likelihood of successful outcomes ''(medium confidence)'' . People who live on small island states do not view relocation as an appropriate or desirable means of adapting to the impacts of climate change ''(high confidence)'' {7.4.3; Cross-Chapter Box MIGRATE in Chapter 7} .

'''Adaptation and sustainable development build peace in conflict-prone regions by addressing the drivers of grievances that lead to conflict and vulnerability to climate change (''' ''high confidence'' ''').''' Environmental peacebuilding (EP) through natural resource sharing, conflict-sensitive adaptation and climate-resilient peacebuilding offer promising avenues for addressing conflict risk, but their efficacy is still to be demonstrated through effective monitoring and evaluation ''(high confidence)'' . Formal institutional arrangements for natural resource management contribute to wider cooperation and peacebuilding ''(high confidence)'' and gender-based approaches provide under-utilised pathways to achieving sustainable peace ''(medium confidence)'' . Inclusion, cross-issue and cross-sectoral integration in policy and programming, and approaches that incorporate different geographical scales and work across national boundaries can support climate-resilient peace ''(high confidence)'' {7.4.5, 7.4.6} .

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