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

==== 14.5.6.1 Heat-Related Mortality and Morbidity ====

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High temperatures currently increase mortality and morbidity in North America ( ''very high confidence'' ), with impacts that vary by age, gender, location and socioeconomic factors ( ''very high confidence'' ). Observed increases in heat-related mortality have been attributed to climate change in North America ( [[#Vicedo-Cabrera--2021|Vicedo-Cabrera et al., 2021]] ). Temperature effects on health vary based on how unusual the temperature is for that time and location ( ''medium evidence, high agreement'' ), highlighting the important role that temperature extremes and variability play in mortality and morbidity ( [[#Li--2013|Li et al., 2013]] ; [[#Lee--2014|Lee et al., 2014]] ; [[#Barreca--2016|Barreca et al., 2016]] ; [[#Allen--2018|Allen and Sheridan, 2018]] ). Adaptation has played an important role in reducing observed heat-related deaths ( [[#Vicedo-Cabrera--2018b|Vicedo-Cabrera et al., 2018b]] ).

Rising temperatures are projected to increase heat-related mortality across emission scenarios this century in North America ( ''very high confidence'' ), although the magnitude of increase varies geographically ( [[#Isaksen--2014|Isaksen et al., 2014]] ; [[#Petkova--2014|Petkova et al., 2014]] ; [[#Wu--2014|Wu et al., 2014]] ; [[#Weinberger--2017|Weinberger et al., 2017]] ; [[#Anderson--2018a|Anderson et al., 2018a]] ; [[#Limaye--2018|Limaye et al., 2018]] ; [[#Marsha--2018|Marsha et al., 2018]] ; [[#Morefield--2018|Morefield et al., 2018]] ). Elderly people ( [[#Isaksen--2014|Isaksen et al., 2014]] ; [[#Limaye--2018|Limaye et al., 2018]] ) and urban areas ( [[#Limaye--2018|Limaye et al., 2018]] ) are projected to experience the greatest increase in heat-related mortality this century. Warming temperatures are also projected to increase heat-related morbidity ( ''medium confidence'' ). For instance, the incidence and treatment costs of asthma attributed to warmer temperatures are projected to increase in Texas by 2040–2050 (A1B) ( [[#McDonald--2015|McDonald et al., 2015]] ).

While heat-related mortality is projected to increase across emissions scenarios and shared socioeconomic pathways, fewer deaths are projected under both lower-emissions scenarios and higher-adaptation scenarios in North America ( ''very high confidence'' ). Heat-related mortality was projected to be 50% less under RCP4.5 compared with RCP8.5 in the USA for SSP3 and SSP5 (Table 14.5; [[#Wu--2014|Wu et al., 2014]] ; [[#Marsha--2018|Marsha et al., 2018]] ).

'''Table 14.5 |''' A summary of adaptation options for different health outcomes in North America

{| class="wikitable"
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! Health outcome

! Adaptation options

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| Heat-related mortality and morbidity

| Future temperature-related health impacts can be reduced by adaptation measures ( [[#Petkova--2014|Petkova et al., 2014]] ; [[#Wu--2014|Wu et al., 2014]] ; [[#Mills--2015b|Mills et al., 2015b]] ; [[#Kingsley--2016|Kingsley et al., 2016]] ; [[#Anderson--2018b|Anderson et al., 2018b]] ; [[#Marsha--2018|Marsha et al., 2018]] ; [[#Morefield--2018|Morefield et al., 2018]] ), including more effective warning and response systems and building designs, enhanced pollution controls, urban planning strategies and resilient health infrastructure ( ''very high confidence'' ) (Figure Box 14.7.1).

|-
| Wildfire-related mortality

| Air quality indices are correlated with many respiratory conditions ( [[#Yao--2013|Yao et al., 2013]] ; [[#Hutchinson--2018|Hutchinson et al., 2018]] ), suggesting that providing air quality information to the public could reduce smoke-related health impacts ( [[#Yao--2013|Yao et al., 2013]] ; [[#Rappold--2017|Rappold et al., 2017]] ). Enhanced coordination between the health sector and fire suppression agencies can also reduce the health impacts of wildfire smoke via improving communication, weather forecasting, mapping, fire shelters and coordinated decision making ( [[#Withen--2015|Withen, 2015]] ), including transnational and cross-jurisdictional actions.

|-
| Vector-borne disease

| Prevention of vector-borne disease currently involves surveillance, reducing environmental risks and promoting individual behaviours to reduce human–vector contact. Top-ranked Canadian West Nile interventions include individual protection (i.e., window screens, wearing lightly coloured clothing), and regional management and mosquito-targeting interventions (i.e., larvicides, vaccination of animal reservoirs, modification of human-made larval sites) ( [[#Hongoh--2016|Hongoh et al., 2016]] ).

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| Water-borne disease

| Climate change is projected to increase water-borne disease risks ( ''medium confidence'' ), particularly in areas with ageing water and wastewater infrastructure in North America ( ''high confidence'' ). In Wisconsin, USA, precipitation changes are projected to increase gastrointestinal illness in children this century (A1B, A2, B1) ( [[#Uejio--2017|Uejio et al., 2017]] ). Slight reductions in precipitation-associated gastrointestinal illness is projected if water treatment infrastructure is upgraded slowly over time; however, if water treatment infrastructure is installed more rapidly, large decreases in precipitation-associated gastrointestinal illness incidence are projected ( [[#Uejio--2017|Uejio et al., 2017]] ), highlighting the benefits of rapidly implementing adaptation actions.

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| Food-borne disease

| Food safety programmes play important roles in reducing the risk of climate-related food-borne disease ( ''high confidence'' ). Integrated health surveillance, more stringent refrigeration temperature controls to limit pathogen growth, targeted communication to the public and food sector, and enhanced coordination between the health and food sectors can reduce risk ( [[#Hueffer--2013|Hueffer et al., 2013]] ; [[#Jones--2013|Jones et al., 2013]] ; [[#Fillion--2014|Fillion et al., 2014]] ; [[#Doyle--2015|Doyle et al., 2015]] ). In Mexico, the projected risk of ''Vibrio parahaemolyticus'' in oysters was 11 times higher in a high-emissions scenario compared with a low-emissions scenario by the end of the century; however, this risk could be substantially lowered with adaptation measures, including improving temperature control ( [[#Ortiz-Jiménez--2018|Ortiz-Jiménez, 2018]] ).

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| Mental health

| Effectiveness of individual and/or group therapy, and place-specific mental health infrastructure, to treat mental health challenges is well proven; yet, there is limited evidence evaluating these interventions within the context of climate change (e.g., [[#Tschakert--2017|Tschakert et al., 2017]] ; [[#Young--2017b|Young et al., 2017b]] ; [[#Cunsolo--2018|Cunsolo and Ellis, 2018]] ).

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