Editing IPCC:AR6/WGII/Chapter-9 (section)

==== 9.10.2.3 Temperature-related Impacts ====

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===== 9.10.2.3.1 Mortality and morbidity =====

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Observed impacts

Emergency department visits and hospital admissions have been shown to increase at moderate-to-high temperatures ( [[#Bishop-Williams--2018|Bishop-Williams et al., 2018]] ; [[#van%20der%20Linden--2019|van der Linden et al., 2019]] ), with increased levels of mortality recorded on days with raised temperatures in Burkina Faso ( [[#Kynast-Wolf--2010|Kynast-Wolf et al., 2010]] ; [[#Diboulo--2012|Diboulo et al., 2012]] ; [[#Bunker--2017|Bunker et al., 2017]] ), Ghana ( [[#Azongo--2012|Azongo et al., 2012]] ), Kenya ( [[#Egondi--2012|Egondi et al., 2012]] ; [[#Egondi--2015|Egondi et al., 2015]] ), South Africa ( [[#Wichmann--2017|Wichmann, 2017]] ; [[#Scovronick--2018|Scovronick et al., 2018]] ), Tanzania ( [[#Mrema--2012|Mrema et al., 2012]] ) and Tunisia ( [[#Bettaieb--2010|Bettaieb et al., 2010]] ; [[#Leone--2013|Leone et al., 2013]] ). Cause of death most commonly involves cardiovascular diseases ( [[#Kynast-Wolf--2010|Kynast-Wolf et al., 2010]] ; [[#Scovronick--2018|Scovronick et al., 2018]] ), but increased incidences of respiratory ( [[#Scovronick--2018|Scovronick et al., 2018]] ), stroke ( [[#Longo-Mbenza--1999|Longo-Mbenza et al., 1999]] ) and non-communicable diseases ( [[#Bunker--2017|Bunker et al., 2017]] ) have also been linked with heat.

Excess death rates from non-optimal temperature in sub-Saharan Africa are estimated to be nearly double the global average, with 24% of the more than 5 million annual deaths globally associated with non-optimal temperature occurring in Africa ( [[#Zhao--2021|Zhao et al., 2021]] ). The region had the world’s highest cold-related excess death ratio and lowest heat-related excess death ratio over the period 2000–2019. However, during this time, cold-related excess deaths declined more rapidly than the increase in heat-related excess deaths, resulting in a net decrease in the excess death ratio from temperature.

Recent estimates of the burden of mortality associated with the additional heat exposure from recent human-caused global warming suggest approximately 43.8% of heat-related mortality in South Africa was attributable to human-caused climate change from 1991–2018 ( [[#Vicedo-Cabrera--2021|Vicedo-Cabrera et al., 2021]] ). In many of South Africa’s 52 districts, this equates to dozens of deaths per year. The elderly and children under 5 years are most vulnerable to heat exposure ( [[#Sewe--2015|Sewe et al., 2015]] ; [[#Scovronick--2018|Scovronick et al., 2018]] ).

Projected risks

Globally, Africa is predicted to suffer disproportionately from higher temperature-related all-cause mortality from global warming, compared to temperate northern hemisphere countries ( [[#Carleton--2018|Carleton et al., 2018]] ). The number of days projected to exceed potentially lethal heat thresholds per year reaches 50–150 days in west Africa at 1.6°C global warming, up to 200 days in west Africa and 100–150 days in central Africa and parts of coastal east Africa at 2.5°C, and over 200 days for parts of west, central and east Africa for &gt;4°C global warming ( [[#Mora--2017|Mora et al., 2017]] ; see Sections 9.5.3–7; Figure 9.15). Projected rates of heat-related mortality among people in the Middle East and north Africa who are older than 65 years increase by 8–20 fold in 2070–2099, compared with 1951–2005, based on RCP4.5 and RCP8.5 (both at &gt;2°C global warming) ( [[#Ahmadalipour--2018|Ahmadalipour and Moradkhani, 2018]] ).

Temperature-related mortality across Africa is projected to escalate with global warming. Above 1.5°C the risk of heat-related deaths rises sharply, with at least 15 additional deaths per 100,000 annually across large parts of Africa, reaching 50–180 additional deaths per 100,000 people annually in regions of north, west, and east Africa for 2.5°C global warming, and increasing to 200–600 per 100,000 people annually for 4.4°C global warming (Figure 9.35; [[#Carleton--2018|Carleton et al., 2018]] ). However, some regions that currently experience cold-related mortality (e.g., Lesotho and Ethiopian Highlands) are projected to have reduced temperature-related mortality risk from warming. GHG mitigation is projected to save tens of thousands of lives: limiting warming to RCP4.5 (2.5°C) rather than RCP8.5 (4.4°C) at the end of the century is projected to avoid on average 71 deaths per 100,000 people annually across Africa with larger reductions in risk in north, west, central and parts of east Africa (Figure 9.35). The cost of mitigating heat stress using energy-intensive cooling methods is expected to be unachievable for many African countries ( [[#Parkes--2019|Parkes et al., 2019]] ; see [[#9.9.4|Section 9.9.4]] ).

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[[File:3befb6fd3a7817461be84909a3b23a3c IPCC_AR6_WGII_Figure_9_035.png]]

'''Figure 9.35 |''' '''Projected temperature-related mortality risk in Africa with increasing global warming.''' Maps show changes in mortality rates in deaths per 100,000 for global warming in the years 2020–2039, 2040–2059 and 2080–2099 for

'''(a)''' intermediate emissions scenario (RCP 4.5);

'''(b)''' a high emissions scenario (RCP 8.5); and

'''(c)''' showing avoidable deaths due to increased emissions mitigation efforts to achieve a lower global warming level (RCP4.5 rather than RCP8.5). These estimates of climate change impacts on mortality rates include temperature-related impacts only. They account for the benefits of income growth and incremental adaptation to climate change, both of which reduce mortality sensitivity to extreme temperatures. Projections were based on income and demographics from Shared Socioeconomic Pathway 3 (SSP3), with future adaptation based on adaptation actions observed in the global historical record. The estimates do not include the costs of the behaviours and investments required to achieve such adaptation ( [[#Carleton--2018|Carleton et al., 2018]] ). Areas shown in burgundy in (c) have fewer deaths due to temperature under RCP8.5 than RCP4.5. This is because cold is currently the greatest driver of temperature-related deaths in these areas, which is projected to be alleviated with increasing levels of global warming ( [[#Zhao--2021|Zhao et al., 2021]] ).

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===== 9.10.2.3.2 Heat stress in specific settings =====

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Heat stress symptoms are prevalent among people in buildings that are poorly ventilated or insulated, or constructed with unsuitable materials (e.g., corrugated metal sheeting). These features are common to many structures in Africa, including slums, informal and low-income settlements, as well as schools and healthcare facilities ( [[#Bidassey-Manilal--2016|Bidassey-Manilal et al., 2016]] ; [[#Naicker--2017|Naicker et al., 2017]] ; [[#Wright--2019|Wright et al., 2019]] ). Temperatures inside these structures can exceed outdoor temperatures by 4°C or more and have large diurnal fluctuations ( [[#Mabuya--2020|Mabuya and Scholes, 2020]] ). Daily wage labourers and residents of urban informal settlements are among the most vulnerable to heat stress because of the urban heat island effect, with congestion, and inadequate ventilation, shade, open space and vegetation ( [[#Bartlett--2008|Bartlett, 2008]] ) being associated with impacts of both hot and cold conditions on public health ( [[#Ramin--2009|Ramin, 2009]] ). Temperature extremes are ''expected'' to result in relatively more deaths in informal settlements than in other settlement types ( [[#Scovronick--2012|Scovronick and Armstrong, 2012]] ).

The urban heat island effect exacerbates current and projected heat stress in Africa’s rapidly growing cities ( [[#Mitchell--2016|Mitchell, 2016]] ) and is discussed in more detail in [[#9.9.3|Section 9.9.3]] .

Escalating temperatures and longer-duration heatwaves are ''expected'' to heavily affect workers already exposed to extreme temperatures, for example, outdoor workers ( [[#Kjellstrom--2018|Kjellstrom et al., 2018]] ) and miners ( [[#El-Shafei--2018|El-Shafei et al., 2018]] ; [[#Nunfam--2019a|Nunfam et al., 2019a]] ; [[#Nunfam--2019b|Nunfam et al., 2019b]] ). Vulnerability may also be high for women who cook food for a living, and children who accompany them, due to prolonged exposure to high temperatures ( [[#Parmar--2019|Parmar et al., 2019]] ). Prisons, commonly poorly ventilated and overcrowded, are also high-risk settings ( [[#Van%20Hout--2019|Van Hout and Mhlanga-Gunda, 2019]] ).

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===== 9.10.2.3.3 Maternal and child health =====

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Exposure to high temperatures during pregnancy has been linked with adverse birth outcomes, including stillbirths or miscarriages ( [[#Asamoah--2018|Asamoah et al., 2018]] ) and long-term behavioural and developmental deficiencies ( [[#Duchoslav--2017|Duchoslav, 2017]] ; [[#MacVicar--2017|MacVicar et al., 2017]] ).

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