Editing IPCC:AR6/WGII/Chapter-4 (section)

=== 4.3.3 Observed Impacts on Water, Sanitation and Hygiene (WaSH) ===

<div id="h2-13-siblings" class="h2-siblings"></div>

AR5 showed that local changes in temperature and rainfall had altered the distribution of some water-related diseases ( ''medium confidence'' ), and extreme weather events disrupt water supplies, impacting morbidity, mortality and mental health ( ''very high confidence'' ) ( [[#Field--2014b|Field et al., 2014b]] ). In addition, melting and thawing of snow, ice and permafrost ( [[#4.2.2|Section 4.2.2]] ) have also adversely impacted water quality, security and health ( ''high confidence'' ) ( [[#IPCC--2019a|IPCC, 2019a]] ) ( [[#4.2.7|Section 4.2.7]] ).

Literature since AR5 confirms that temperature, precipitation and extreme weather events are linked to increased incidence and outbreaks of water-related and neglected tropical diseases ( [[#Colón-González--2016|Colón-González et al., 2016]] ; [[#Levy--2016|Levy et al., 2016]] ; [[#Azage--2017|Azage et al., 2017]] ; [[#Harp--2021|Harp et al., 2021]] ) ( ''high confidence'' ). For example, the rainy season in Senegal has been associated with an 84% increase in relative risk of childhood diarrhoea, and an additional wet day per week was associated with up to 2% increases in diarrhoeal disease in Mozambique ( [[#Thiam--2017|Thiam et al., 2017]] ; [[#Horn--2018|Horn et al., 2018]] ). In Ecuador, increases of 1.5 cases of diarrhoea per 1000 were associated with heavy rainfall after dry periods, while a decrease of one case per 1000 was associated with heavy rain after wet periods ( [[#Carlton--2014|Carlton et al., 2014]] ). Floods have been associated with 22% increases in relative risk of diarrhoea in China ( [[#Liu--2018c|Liu et al., 2018c]] ). In addition, higher levels of faecal contamination of drinking water and hands (i.e., lack of WaSH) has been statistically significantly associated with increased child diarrhoea ( [[#Goddard--2020|Goddard et al., 2020]] ).

In 2020, 2 billion people lacked access to uncontaminated water, while 771 million lacked basic sanitation services, primarily in sub-Saharan Africa and rural areas ( [[#WHO%20and%20UNICEF--2021|WHO and UNICEF, 2021]] ). Even in high-income countries, poor-quality drinking water can be a health issue ( [[#Murphy--2014|Murphy et al., 2014]] ). For example, in a sampled population in Canada, reported exposure to exposure routes for waterborne illness included 7% from private wells and 71.8% from municipal water ( [[#David--2014|David et al., 2014]] ). Drinking water treatment can be compromised by degraded source water quality and extreme weather events, including droughts, storms, ice storms and wildfires that overwhelm or cause infrastructure damage ( [[#Sherpa--2014|Sherpa et al., 2014]] ; [[#Khan--2015|Khan et al., 2015]] ; [[#Howard--2016|Howard et al., 2016]] ; [[#White--2017|White et al., 2017]] ) ( ''high confidence'' ). Adverse health effects are exacerbated due to the absence of adequate WaSH, particularly in poorer households ( [[#Khan--2015|Khan et al., 2015]] ; [[#Kostyla--2015|Kostyla et al., 2015]] ; [[#Cissé--2016|Cissé et al., 2016]] ), WaSH infrastructure failure ( [[#Khan--2015|Khan et al., 2015]] ; [[#Wanda--2017|Wanda et al., 2017]] ) or inadequate WaSH facilities in emergency shelters ( [[#Alam--2014|Alam and Rahman, 2014]] ). For example, WaSH coverage decreased from 65% to 51% due to damage from floods and earthquakes in Malawi ( [[#Wanda--2017|Wanda et al., 2017]] ). Loss of electricity also impacts WaSH service delivery ( [[#Cashman--2014|Cashman, 2014]] ), and infrastructure damage caused by climate hazards may reverse progress on universal access to WaSH ( [[#Kohlitz--2017|Kohlitz et al., 2017]] ) ( ''limited evidence, high agreement'' ). In addition, wastewater outflows have been associated with a 13% increased relative risk of gastrointestinal illness through contaminated drinking water sources ( [[#Jagai--2015|Jagai et al., 2015]] ) ( ''limited evidence, high agreement'' ). Harmful algal blooms represent an emerging health risk, but lack of monitoring and reporting prevent risk exposure assessments ( [[#Carmichael--2016|Carmichael and Boyer, 2016]] ; [[#Nichols--2018|Nichols et al., 2018]] ) ( ''limited evidence, high agreement'' ). Chemical contaminants (e.g., nitrates, arsenic) have been linked to non-communicable diseases, including neurological disorders, liver and kidney damage, and cancers ( [[#Jones%20Rena--2016|Jones Rena et al., 2016]] ), and to some water-related diseases (e.g., schistosomiasis) ( ''low evidence, medium agreement'' ).

Water insecurity and inadequate WaSH have been associated with increased disease risk ( ''high confidence'' ), stress and adverse mental health ( ''limited evidence, medium agreement'' ), food insecurity and adverse nutritional outcomes, and poor cognitive and birth outcomes ( ''limited evidence, medium agreement'' ) ( [[#Workman--2017|Workman and Ureksoy, 2017]] ; [[#Sclar--2018|Sclar et al., 2018]] ; [[#Boateng--2020|Boateng et al., 2020]] ; [[#Rosinger--2020|Rosinger and Young, 2020]] ; [[#Wutich--2020|Wutich et al., 2020]] ). Climate-induced water scarcity and supply disruptions disproportionately impact women and girls. The necessity of water collection takes away time from income-generating activities, child care and education ( [[#Yadav--2018|Yadav and Lal, 2018]] ; [[#Schuster--2020|Schuster et al., 2020]] ) ( ''medium evidence, medium agreement'' ). Consumption of larger volumes of water is essential for healthy women during pregnancy, lactation and caregiving, which increases the amount of water that has to be fetched. Fetching of water is associated with increased risk of sexual abuse, demand for sexual favours at controlled water collection points, physical injuries (e.g., musculoskeletal or from animal attacks), domestic violence for not completing daily water-related domestic tasks ( ''limited evidence, high agreement'' ), and poorer maternal and child health (Mercer and [[#Hanrahan--2017|Hanrahan, 2017]] ; [[#Pommells--2018|Pommells et al., 2018]] ; [[#Anwar--2019|Anwar et al., 2019]] ; [[#Collins--2019a|Collins et al., 2019a]] ; [[#Geere--2020|Geere and Hunter, 2020]] ; [[#Venkataramanan--2020|Venkataramanan et al., 2020]] ) ( ''medium evidence, high agreement'' ). Menstrual hygiene management is a public health issue but poorly linked to climate change, despite relationships between lack of adequate WaSH, poor menstrual hygiene, and urinary tract infections ( [[#Ellis--2016|Ellis et al., 2016]] ; [[#Pouramin--2020|Pouramin et al., 2020]] ). Water insecurity also affects emotional, spiritual and cultural relationships that are often critical to Indigenous health ( [[#Wilson--2019|Wilson et al., 2019]] ) ( ''limited evidence, high agreement'' ).

There are gaps in data on climate-driven water-related disease burden for both infectious and non-communicable diseases. Increased demands for water and WaSH services for infectious diseases, such as HIV/AIDS and COVID-19 (Box 4.4) exacerbate existing vulnerabilities and inequities ( [[#Stanley--2017|Stanley et al., 2017]] ; [[#Armitage--2020a|Armitage and Nellums, 2020a]] ; [[#Rodriguez-Lonebear--2020|Rodriguez-Lonebear et al., 2020]] ). Additionally, limited research has been undertaken to quantify the effects of climate-compromised WaSH on health and well-being.

In summary, WaSH-related household water insecurity and disease incidence are products of geography, politics, social and environmental determinants, vulnerability and climate change ( [[#Bardosh--2017|Bardosh et al., 2017]] ; [[#Stoler--2021|Stoler et al., 2021]] ).

<div id="4.3.4" class="h2-container"></div>

<span id="observed-impacts-on-urban-and-peri-urban-sectors"></span>