Editing IPCC:AR6/WGII/Chapter-7 (section)

==== 7.2.4.4 Observed Impacts on Malnutrition ====

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''Climate variability and change contribute to food insecurity that can lead to malnutrition, including undernutrition, overweight and obesity, and to disease susceptibility, particularly in low- and middle-income countries'' ( ''high confidence'' ) ''.'' Since AR5, analyses of the links between climate change and food expanded beyond undernutrition to include the impacts of climate change on a wider set of diet- and weight-related risk factors and their impacts on NCDs, along with the role of dietary choices for GHG emissions ( [[#IPCC--2019b|IPCC, 2019b]] ) including dietary inadequacy (deficiencies, excesses or imbalances in energy, protein and micronutrients), infections and sociocultural factors (Global Nutrition Report 2020). Undernutrition exists when a combination of insufficient food intake, health, and care conditions results in one or more of the following: underweight for age, short for age (stunted), thin for height (wasted), or functionally deficient in vitamins and/or minerals (micronutrient malnutrition or ‘hidden hunger’). Food insecurity and poor access to nutrient-dense food contribute not only to undernutrition but also to obesity and susceptibility to NCDs in low- and middle-income countries ( [[#FAO--2018|FAO et al., 2018]] ; [[#Swinburn--2019|Swinburn et al., 2019]] ).

Globally, more than 690 million people are undernourished, 144 million children are stunted (chronic undernutrition), 47 million children are wasted (acute undernutrition), and more than 2 billion people have micronutrient deficiencies ( [[#FAO--2020|FAO, 2020]] ). More than 135 million people across 55 countries experienced acute hunger requiring urgent food, nutrition and livelihood assistance in 2019 (FSIN/GNAFC, 2020). The COVID-19 pandemic is projected to increase the number of acutely food insecure people to 270 million people ( [[#FSIN--2020|FSIN, 2020]] ) and worsen malnutrition levels ( [[#FAO--2020|FAO et al., 2020]] ; [[#Rippin--2020|Rippin et al., 2020]] ). The relationships between climate change and obesity vary based on geography, population sub-groups and/or stages of economic growth and population growth (An et al., 2017). Increasing temperatures could contribute to obesity through reduced physical activity, increased prices of produce or shifts in eating patterns of populations towards more processed foods ( [[#An--2018|An et al., 2018]] ). In the largest global study to date exploring the connections between child diet diversity and recent climate, data from 19 countries in six regions (Asia, Central America, South America, north Africa, southeast Africa and west Africa) indicated significant reductions in diet diversity associated with higher temperatures and significant increases in diet diversity associated with higher precipitation ( [[#Niles--2021|Niles et al., 2021]] ).

Climate change can affect the four aspects of food security: food production and availability, stability of food supplies, access to food and food utilisation ( [[#IPCC--2019b|IPCC, 2019b]] ). Access to sufficient food does not guarantee nutrition security. Extreme weather and climate events can result in inadequate or insufficient food consumption, increasing susceptibility to infectious diseases ( [[#Rodriguez-Llanes--2016|Rodriguez-Llanes et al., 2016]] ; [[#Gari--2017|Gari et al., 2017]] ; [[#Kumar--2016|Kumar et al., 2016]] ; [[#Lazzaroni--2016|Lazzaroni and Wagner, 2016]] ) but also to being overweight or obese and increasing susceptibility to non-communicable diseases in low- and middle-income countries (FAO, 2018; [[#Swinburn--2019|Swinburn et al., 2019]] ).

Nearly half of all deaths in children under five years of age are attributable to undernutrition, putting children at greater risk of dying from common infections. Undernutrition in the first 1,000 days of a child’s life can lead to stunted growth, which can result in impaired cognitive ability and reduced future school and work performance and the associated costs of stunting in terms of lost economic growth can be of the order of 10% of GDP yr –1 in Africa (UNICEF/WHO/WBG, 2019).

At the same time, diseases associated with high-calorie, unhealthy diets are increasing globally, with 38.3 million overweight children under five years of age (Global Nutrition Report, 2018), 2.1 billion overweight or obese adults and the global prevalence of diabetes almost doubling in the past 30 years ( [[#Swinburn--2019|Swinburn et al., 2019]] ). Unbalanced diets, such as diets low in fruits and vegetables and high in red and processed meat, are the number one risk factor for mortality globally and in most regions (Gakidou et al., 2018; [[#Afshin--2019|Afshin et al., 2019]] ).

Socioeconomic factors that mediate the influence of climate change on nutrition include cultural and societal norms; governance, institutions, policies and fragility; human capital and potential; and social position and access to healthcare, education and food aid ( [[#Rozenberg--2017|Rozenberg, 2017]] ; Alkerwi et al. 2015; [[#Tirado--2017|Tirado, 2017]] ; [[#FAO--2018|FAO et al., 2018]] ; Global Nutrition Report 2020). Extreme events may affect access to adequate diets, leading to malnutrition and increasing the risk of disease ( [[#Beveridge--2019|Beveridge et al., 2019]] ; [[#Rodriguez-Llanes--2016|Rodriguez-Llanes et al., 2016]] ; [[#Gari--2017|Gari et al., 2017]] ; [[#Kumar--2016|Kumar et al., 2016]] ; [[#Lazzaroni--2016|Lazzaroni and Wagner, 2016]] ; [[#Thiede--2020|Thiede and Gray, 2020]] ).

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