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

===== 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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