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

=== 5.12.2 Mechanisms for Climate Change Impacts on Food Security ===

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Climate change is increasing the number of people experiencing food insecurity through greater incidence and severity of climatic impact drivers (CIDs), ( [[#Seneviratne--2021|Seneviratne et al., 2021]] ) such as extreme heat, drought and floods. Increasing CO 2 concentrations have positive effects on food and forage crops by enhancing photosynthesis and alleviating drought stresses (5.4.3.1, 5.5.3.1) but have negative effects on nutrient concentrations in food crops. Ocean acidification is also caused by increasing CO 2 , causing negative impacts on aquatic systems. Tropospheric ozone concentrations already hinder crop production ( [[#5.4.1.4|Section 5.4.1.4]] ). Several CIDs increase the number of people experiencing food insecurity ( ''high confidence'' ) (SROCC 2019, [[#FAO--2018|FAO et al., 2018]] ; [[#Mbow--2019|Mbow et al., 2019]] ; [[#Baker--2020|Baker and Anttila-Hughes, 2020]] ; Table 5.12).

Vulnerability to climate impacts on food security and nutrition varies by region and group. Countries that experience CIDs such as extreme heat, severe drought or floods and have a large proportion of the population dependent on rainfed agriculture or livestock for their livelihoods and food supply have experienced rising food insecurity due to climate change impacts ( [[#FAO--2018|FAO et al., 2018]] ; [[#Cooper--2019|Cooper et al., 2019]] ; [[#Mbow--2019|Mbow et al., 2019]] ). Children in Sub-Saharan Africa are particularly at risk of undernutrition and mortality from increasing temperatures ( [[#Belesova--2019|Belesova et al., 2019]] ; [[#Baker--2020|Baker and Anttila-Hughes, 2020]] ). An additional estimated 5.9 million children became underweight because of rising temperatures in 51 countries affected by ENSO intensity in 2015–2016 ( [[#Anttila-Hughes--2021|Anttila-Hughes et al., 2021]] ). Low-income urban households and marginalised groups such as landless and ethnic minorities are at risk of increased food insecurity due in part to climate change extreme events such as extended drought, floods or cyclones that interrupt supply chains and impact livelihoods ( [[#Rodriguez-Llanes--2016|Rodriguez-Llanes et al., 2016]] ; [[#FAO--2018|FAO et al., 2018]] ; [[#Algur--2021|Algur et al., 2021]] ). A systematic review in India found that women often experience greater workloads and stress during drought events ( [[#Algur--2021|Algur et al., 2021]] ).

In the subsequent sections, the four dimensions of food security will be discussed in relation to observed and projected impacts and vulnerabilities (Table 5.14).

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