Editing IPCC:AR6/WGII/Chapter-15 (section)

==== 15.3.4.2 Human Health and Well-Being ====

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Small islands face disproportionate health risks associated with changes in temperature and precipitation, climate variability, and extremes (Cross-Chapter Box INTERREG in Chapter 16; KR4 in [[#15.3|Section 15.3.9]] , Figure 15.5). Climate change is projected to increase the current burden of climate-related health risks ( [[#Weatherdon--2016|Weatherdon et al., 2016]] ; [[#Ebi--2018|Ebi et al., 2018]] ; [[#Schnitter--2019|Schnitter et al., 2019]] ). Health risks can arise from exposures to extreme weather and climate events, including heatwaves; changes in ecological systems associated with changing weather patterns that can result, for example, in more disease vectors, or in compromised safety and security of water and food; and exposures related to disruption of health systems, migration, and other factors (see Cross-Chapter Box ILLNESS in Chapter 2; [[#McIver--2016|McIver et al., 2016]] ; [[#Mycoo--2018a|Mycoo, 2018a]] ; [[#WHO--2018|WHO, 2018]] ).

Extreme weather and climate events, particularly TCs, floods, drought, and heatwaves can cause injuries, infectious diseases, and deaths (Box 15.1; [[#Schütte--2018|Schütte et al., 2018]] ). For example, Category 5 TC Winston hit Fiji on 20 February 2016. During the national state of emergency (7 March and 29 May 2016), the World Health Organization portable toolkit for an early warning alert and response system (EWARS in a Box) was deployed within 24 h; it recorded 34,113 cases of the nine syndromes among 326,861 consultations in a population of about 900,000; 48% of cases were influenza-like illnesses, 30% were acute watery diarrhoea, and 13% were suspected cases of dengue. There also were 583 cases of Zika-like illness (1.7% of all cases) and two large outbreaks of viral conjunctivitis (total of 880 cases). During TC Maria in Puerto Rico, there were more deaths per 100,000 among individuals living in municipalities with the lowest socioeconomic development and for men 65 years of age or older ( [[#Santos-Burgoa--2018|Santos-Burgoa et al., 2018]] ); this excess risk persisted for at least 1 year after the event. The first human cases of leptospirosis in the U.S. Virgin Islands occurred in 2017 after TC Irma and Maria. TCs also can affect treatment and care for people with non-communicable diseases, including exacerbation or complications of illness and premature death ( [[#Ryan--2015|Ryan et al., 2015]] ).

Heat-related mortality and risks of occupational heat stress in small island states are projected to increase with higher temperatures ( [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ; [[#Mendez-Lazaro--2018|Mendez-Lazaro et al., 2018]] ). Higher temperatures can also affect the productivity of outdoor workers ( [[#Taylor--2021|Taylor et al., 2021]] ). Climate change, urbanisation, and air pollution are risk factors for the rise of allergic diseases in Asia Pacific ( [[#Pawankar--2020|Pawankar et al., 2020]] ).

Tropical and subtropical islands face risks from vector-borne diseases, such as malaria, dengue fever, and the Zika virus. El Niño events can increase the risk of diseases such as Zika virus by increasing biting rates, decreasing mosquito mortality rates and shortening the time required for the virus to replicate within the mosquito ( [[#Caminade--2017|Caminade et al., 2017]] ). By combining disease prediction models with climate indicators that are routinely monitored, alongside evaluation tools, it is possible to generate probabilistic dengue outlooks in the Caribbean and early warning systems ( [[#Oritz--2015|Oritz et al., 2015]] ; [[#Lowe--2018|Lowe et al., 2018]] ). Projections suggest that more individuals will become at risk of dengue fever by the 2030s and beyond because of an increasing abundance of mosquitos and larger geographic range ( [[#Ebi--2018|Ebi et al., 2018]] ). Projected increases in mean temperature could double the dengue burden in New Caledonia by 2100 ( [[#Teurlai--2015|Teurlai et al., 2015]] ). In the Caribbean, Saharan dust transported across the Atlantic can interact with Caribbean seasonal climatic conditions to become respirable and contribute to asthma presentations at the emergency department (See Table 15.5; [[#Akpinar-Elci--2015|Akpinar-Elci et al., 2015]] ).

Ciguatera fish poisoning (CFP) is a foodborne illness caused by toxic dinoflagellate algae that proliferate on degraded coral reefs and that can contaminate reef fish; symptoms can remain for a few weeks to months. CFP occurs in tropical and subtropical regions, primarily in the South Pacific and Caribbean, but wherever reef fish are consumed ( [[#Traylor--2020|Traylor and Singhal, 2020]] ). In the Caribbean Sea, increasing ocean temperatures are expected to stabilise or slightly decrease the incidence of CFP because of shifts in species distribution of dinoflagellates associated with CFP ( [[#Kibler--2015|Kibler et al., 2015]] ). CFP is endemic in the Cook Islands and French Polynesia, where incidence is associated with SST anomalies ( [[#Zheng--2020|Zheng et al., 2020]] ). In the Canary Islands, tropicalisation trends due to climate change are expected to increase CFP occurrence in the future ( [[#Rodriguez--2017|Rodriguez et al., 2017]] ). In addition, in the Caribbean, increased density of ''Sargassum'' algae, possibly due to ocean temperature impacts on ocean currents compounded by agricultural pollution, may lead to increased respiratory illnesses ( [[#Resiere--2018|Resiere et al., 2018]] ; 2019; 2020).

Climate-driven changes in the ability to access locally grown or harvested food, either through environmental degradation or changes in extreme event magnitude and/or frequency, can increase dependence on imported food and increase rates of malnutrition and non-communicable diseases ( [[#Springmann--2016|Springmann et al., 2016]] ; [[#WHO--2018|WHO, 2018]] ; [[#Savage--2019|Savage et al., 2019]] ; [[#Lieber--2020|Lieber et al., 2020]] ). Projections suggest that local food accessibility could be reduced by 3.2% in the low- and middle-income countries of the Western Pacific (including the Philippines, Fiji, Papua New Guinea, Solomon Islands, and other Pacific islands) by 2050, with approximately 300,000 associated deaths possible ( [[#Springmann--2016|Springmann et al., 2016]] ). A climate change-related 20% decline in coral reef fish production in some Pacific Island countries by 2050 could exacerbate the population growth-driven gap between volume of fish needed for nutritional security and fish available through sustained harvest ( [[#Bell--2013|Bell et al., 2013]] ; [[#Cauchi--2019|Cauchi et al., 2019]] ; [[#Savage--2019|Savage et al., 2019]] )).

Heavy reliance on aquifers and rainwater harvesting in small islands, particularly atolls, coupled with overcrowding, population growth and contamination increase the risk of waterborne disease ( [[#McIver--2014|McIver et al., 2014]] ; 2016; [[#Strauch--2014|Strauch et al., 2014]] ). For example, seasonal rainfall in Kiribati is associated with waterborne disease (such as diarrhoea, cholera, and typhoid fever). Future projections indicate increases in the number of days of heavy rainfall by 2050, suggesting future increases in risk in heavily populated areas ( [[#McIver--2014|McIver et al., 2014]] ). Damage to water and sanitation services can cause infectious disease outbreaks, such as the cholera outbreak that occurred in Haiti following TC Matthew ( [[#Raila--2017|Raila and Anderson, 2017]] ; [[#Hulland--2019|Hulland et al., 2019]] ).

Evidence is emerging of the mental health impacts of climate change (limited evidence). Tuvaluans are experiencing distress because of the local environmental impacts caused or exacerbated by climate change, and by hearing about the potential future consequences of climate change ( [[#Gibson--2020|Gibson et al., 2020]] ).

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