Editing IPCC:AR6/WGII/Chapter-5 (section)

=== 5.12.3 Observed Impacts ===

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==== 5.12.3.1 Impacts on food availability ====

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All food production systems (crops, livestock, marine, fish, mixed, aquaculture) have been undermined by climate change and are expected to experience larger impacts in the future as described in earlier sections (see Sections 5.4.1, 5.5, 5.8, 5.9, 5.10). In addition, sudden production losses from extreme climate events can reduce food security ( [[#FAO--2018|FAO et al., 2018]] ; [[#Cottrell--2019|Cottrell et al., 2019]] ; [[#FAO--2020|FAO et al., 2020]] ; [[#Anttila-Hughes--2021|Anttila-Hughes et al., 2021]] ). For example, a 2007 drought-induced crop failure in southern Africa led to severe food insecurity in Lesotho because of the land-locked country’s dependence on imports from South Africa that aggravated food availability and access under conditions of declining food production and land degradation ( [[#Verschuur--2021|Verschuur et al., 2021]] ). Pest and disease outbreaks in both crops and livestock due to climate change (Sections 5.4.1, 5.5.1) have also impacted food availability and access (see Box 5.8 Desert Locust case study). Loss in labour productivity from climate-change-related heat stress is a growing problem.

Climate change affects agricultural labour productivity through increased intensity and frequency of heat stress events, with those performing physical labour in high humidity and ambient temperatures most vulnerable to heat stress ( ''high confidence'' ) (Hsiang et al.; [[#FAO--2018|FAO et al., 2018]] ; [[#Kjellström--2019|Kjellström et al., 2019]] ; [[#Antonelli--2020|Antonelli et al., 2020]] ; [[#Shayegh--2020|Shayegh et al., 2020]] ). Labour capacity, supply and productivity loss in moderate outdoor work due to heat stress is estimated between 2% and 14%, depending on the location and indicator ( [[#Ioannou--2017|Ioannou et al., 2017]] ; [[#Kjellstrom--2018|Kjellstrom et al., 2018]] ), with an overall estimate of 5.3% loss in productivity for outdoor work between 2000 and 2015 ( ''medium confidence'' ) ( [[#Watts--2018|Watts et al., 2018]] ) but as high as 14% in low-income tropical countries ( [[#Antonelli--2020|Antonelli et al., 2020]] ; [[#Shayegh--2020|Shayegh et al., 2020]] ). Highly vulnerable occupation groups affected by heat stress include farmers, farmworkers and livestock keepers working outdoors in low-income tropical countries ( ''high confidence'' ) ( [[#Zander--2015|Zander et al., 2015]] ; [[#Kjellstrom--2016|Kjellstrom et al., 2016]] ; [[#Flouris--2018|Flouris et al., 2018]] ; [[#Kjellstrom--2018|Kjellstrom et al., 2018]] ; [[#Levi--2018|Levi et al., 2018]] ). Farmworkers and small-scale food producers in high- and middle-income countries involved in outdoor labour are also affected by heat stress ( [[#Zander--2015|Zander et al., 2015]] ; [[#Gosling--2018|Gosling et al., 2018]] ; [[#Szewczyk--2018|Szewczyk et al., 2018]] ; [[#Watts--2021|Watts et al., 2021]] ). There is also evidence that heat stress is affecting labour supply through variation in nutrition intake ( [[#Antonelli--2020|Antonelli et al., 2020]] ).

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==== 5.12.3.2 Impacts on food access (physical, economic and socio-cultural) and vulnerabilities ====

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Increased extreme events (e.g., droughts, floods and tropical storms; [[#Seneviratne--2021|Seneviratne et al., 2021]] ) due to climate change are key drivers of recent rises in food insecurity rates and severe food crises in some regions ( ''high confidence'' ) ( [[#5.4.1|Section 5.4.1]] , [[#Yeni--2017|Yeni and Alpas, 2017]] ; [[#FAO--2018|FAO et al., 2018]] ; [[#Cooper--2019|Cooper et al., 2019]] ; [[#Baker--2020|Baker and Anttila-Hughes, 2020]] ; [[#Bogdanova--2021|Bogdanova et al., 2021]] ; [[#Ilboudo%20Nébié--2021|Ilboudo Nébié et al., 2021]] ). Extreme weather events reduce physical and economic access to food, increase food prices, and compound underlying conditions of food insecurity and malnutrition such as low access to diverse healthy foods and safe water ( [[#FAO--2018|FAO et al., 2018]] ; [[#Niles--2021|Niles et al., 2021]] ). Increased incidence of severe drought conditions since 2005 is contributing to food insecurity in affected regions, including Africa, Asia and the Pacific (Chapter 7, [[#Phalkey--2015|Phalkey et al., 2015]] ; [[#FAO--2018|FAO et al., 2018]] ; [[#Cooper--2019|Cooper et al., 2019]] ; [[#Ilboudo%20Nébié--2021|Ilboudo Nébié et al., 2021]] ; [[#Verschuur--2021|Verschuur et al., 2021]] ;). In Arctic western Siberia, high temperatures, melting ice and forest and tundra fires have degraded reindeer pastures; Indigenous Peoples have reduced traditional diets and increased purchased food with increases in hypertension and related health impacts ( [[#Bogdanova--2021|Bogdanova et al., 2021]] ).

There is growing evidence that anthropogenic climate warming has already intensified climate extreme events induced by large-scale SST oscillations such as ENSO ( [[#Herring--2018|Herring et al., 2018]] ; [[#Seneviratne--2021|Seneviratne et al., 2021]] ). For example, the 2015–2016 El Niño, the strongest in the past 145 years, induced severe droughts in Southeast Asia and eastern and southern Africa, some intensified by anthropogenic warming ( [[#Funk--2018|Funk et al., 2018]] ). As a result, 20.5 million people faced acute food insecurity in 2016 ( [[#FSIN--2017|FSIN, 2017]] ) and an estimated additional 5.9 million children became underweight ( [[#Anttila-Hughes--2021|Anttila-Hughes et al., 2021]] ).

Weather extreme events increased food prices and food price volatility ( [[#Peri--2017|Peri, 2017]] ), thereby worsening food insecurity ( [[#Shiferaw--2014|Shiferaw et al., 2014]] ; [[#Bene--2015|Bene et al., 2015]] ; [[#Miyan--2015|Miyan, 2015]] ; [[#FAO--2018|FAO et al., 2018]] ; [[#Ilboudo%20Nébié--2021|Ilboudo Nébié et al., 2021]] ). Rising food prices can affect conflict, political instability and migration ( [[#Bush--2017|Bush and Martiniello, 2017]] ), but the relationship between climate change, political instability and conflict is often mediated by other underlying factors such as poor governance (Chapter 7.2.7, [[#Mach--2019|Mach et al., 2019]] ; [[#Selby--2019|Selby, 2019]] ).

Low-income urban and rural households who are net food buyers are particularly affected by food price increases, with reduction in consumption of diverse food groups ( ''high confidence'' ) ( [[#Green--2013|Green et al., 2013]] ; [[#Villasante--2015|Villasante et al., 2015]] ; [[#FAO--2018|FAO et al., 2018]] ). Depending on the context, particular groups, including women, ethnic and religious minorities, will be more vulnerable to worsening food insecurity from climate change impacts ( [[#Clay--2018|Clay et al., 2018]] ; [[#Jantarasami--2018|Jantarasami et al., 2018]] ; [[#Nature%20climate%20change%20Editorials--2019|Nature climate change Editorials, 2019]] ; [[#Algur--2021|Algur et al., 2021]] and see Cross-Chapter Box GENDER in Chapter 18). Indigenous Peoples are often more vulnerable to climate change, due to conditions of poverty, limited resources, discrimination and marginalisation ( ''high confidence'' ) ( [[#Smith--2016|Smith and Rhiney, 2016]] ; [[#Vinyeta--2016|Vinyeta et al., 2016]] ; [[#Jantarasami--2018|Jantarasami et al., 2018]] ). Indigenous Peoples may experience loss of culturally significant foods and declining traditional ecological knowledge ( [[#Dounias--2017|Dounias and Ichikawa, 2017]] ; [[#Ross--2020|Ross and Mason, 2020]] ; 5.7).

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==== 5.12.3.3 Impacts on food utilisation and vulnerabilities ====

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Food utilisation refers to the way the body most effectively uses food, and includes food preparation, food quality and intra-household distribution. Food utilisation is affected by climate change in several ways: food safety, dietary diversity and food quality ( [[#Aberman--2014|Aberman and Tirado, 2014]] ).

Climate change have increased food safety risks ( ''high confidence'' ), including foodborne zoonotic animal diseases (5.5), and marine toxins from HABs (Sections 5.8, 5.9) and mycotoxins ( [[#5.11|Section 5.11]] ). Other foodborne and waterborne infectious diseases such as cholera are further covered in Chapter 7.

Weather variability and extreme events ( [[#Seneviratne--2021|Seneviratne et al., 2021]] ) have reduced availability and access to diverse foods to sell and to purchase in rural markets, thereby reducing access to affordable, diverse foods for both rural small-scale producers and net consumers, particularly for landlocked and low-income countries ( ''high confidence'' ) ( [[#Pant--2014|Pant et al., 2014]] ; [[#Villasante--2015|Villasante et al., 2015]] ; [[#Alston--2016|Alston and Akhter, 2016]] ; [[#FAO--2018|FAO et al., 2018]] ; [[#Park--2019|Park et al., 2019]] ; [[#Niles--2021|Niles et al., 2021]] ) and otherwise marginalised communities ( [[#Algur--2021|Algur et al., 2021]] ). One study of 87 countries and 150 extreme events estimated that low-income food deficit and landlocked countries had reduced nutrient supply ranging from −1.6 to −7.6% of average supply, a significant portion of a healthy child’s average dietary intake ( [[#Park--2019|Park et al., 2019]] ).

Rural children in low-income countries are at particular risk of undernutrition from climate change impacts, due to a combination of factors: potential reduction in food quantity and quality from heat impacts; greater exposure from outdoor play and agricultural activities; and increased likelihood of heat exhaustion and vector-borne and diarrheal diseases ( [[#Oppenheimer--2016|Oppenheimer and Anttila-Hughes, 2016]] ). A study of child growth data in 30 countries in Africa between 1993 and 2012 found that increased temperature was significantly related to children’s wasting ( [[#Baker--2020|Baker and Anttila-Hughes, 2020]] ). Another study examined 30 years of climate data and child dietary diversity outcomes in 19 countries, and found that higher-than-average annual temperatures correlated with declines in child diet diversity at levels equal to or greater than other factors which often are the focus of policy, such as market access or education ( [[#Niles--2021|Niles et al., 2021]] ).

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==== 5.12.3.4 Impacts on food stability ====

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Climate change has already changed the start and duration of the growing season and increased variability of rainfall in some places, with impacts on food intake and nutritional status and income for low-income and small-scale producers ( ''medium evidence'' , ''high agreement'' , ( [[#FAO--2018|FAO et al., 2018]] ; [[#Cooper--2019|Cooper et al., 2019]] ). Evidence to date suggests that climate change has negative impacts on the stability of food supply over the medium to long term, thereby affecting food stability ( [[#Myers--2017b|Myers et al., 2017b]] ). Increasing number and intensity of adverse weather events, driven by climate change ( [[#Seneviratne--2021|Seneviratne et al., 2021]] ), are important factors decreasing food stability, through reduced availability, increased local price volatility, reduced livelihoods for food producers and disruption to food transport ( [[#Toufique--2014|Toufique and Belton, 2014]] ; [[#Verma--2014|Verma et al., 2014]] ; [[#Ruiz%20Meza--2015|Ruiz Meza, 2015]] ; [[#Clay--2018|Clay et al., 2018]] ; [[#FAO--2018|FAO et al., 2018]] ; [[#Mbow--2019|Mbow et al., 2019]] ).

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'''Box 5.9: Desert Locust Case Study: Climate as Compounding Effect on Food Security'''
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At the end of 2019, desert locust swarms infested Eastern Africa and caused widespread damage to crops and pastures, threatening food security and livelihoods ( [[#Kimathi--2020|Kimathi et al., 2020]] ; [[#Salih--2020|Salih et al., 2020]] ). The FAO estimates that over 200,000 ha of crop and pastureland were damaged, rendering 2 million people in the region acutely food insecure ( [[#IGAD--2020|IGAD, 2020]] ). The desert locust infestation was facilitated by two tropical cyclones that created desert lakes in a usually dry region of Saudi Arabia. Moist soils, warm temperatures and ample vegetation provided a suitable environment for desert locust breeding and migration to Yemen and Somalia, where the pest remained uncontrolled due to conflict and spread to neighbouring countries. A series of political and socioeconomic weaknesses such as armed conflict, limited financial resources and lack of early actions compounded the impact of the current invasion and made it the most damaging in 70 years ( [[#Meynard--2020|Meynard et al., 2020]] ; [[#Salih--2020|Salih et al., 2020]] ).

Although desert locusts have been here for centuries, this recent outbreak can be linked to a unique feature of the positive IOD event, in part caused by long-term trends in SSTs ( [[#Wang--2020a|Wang et al., 2020a]] ). The warming of the western Indian Ocean has increased frequency and intensity of severe weather, including tropical cyclones ( [[#Roxy--2014|Roxy et al., 2014]] ; Murakami H, 2017; [[#Roxy--2017|Roxy et al., 2017]] ). Under a 1.5°C warmer climate, extreme positive IODs are anticipated to occur twice as often, which could also increase the occurrence of pest outbreaks ( [[#Cai--2018|Cai et al., 2018]] ).

Climate change increases the need for robust adaptation measures, such as transnational early-warning systems, biological control mechanisms, crop diversification and further technological innovations in areas of sound and light stimulants, remote sensing, and modelling for tracking and forecasting of movement ( [[#Maeno--2018|Maeno and Ould Babah Ebbe, 2018]] ; [[#Peng--2020|Peng et al., 2020]] ). The desert locust outbreak and the role of the Indian Ocean warming show that the impacts of climate change can increase unpredictable events. Extreme weather events act as a compounding effect, exacerbated further by weak governance systems, political instability, limited financial resources and poor early-warning systems ( [[#Meynard--2020|Meynard et al., 2020]] ).

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