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

==== 7.2.2.2 Food supply instability ====

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Stability of food supply is expected to decrease as the magnitude and frequency of extreme events increase, disrupting food chains in all areas of the world ( ''medium evidence, high agreement'' ) (Wheeler and Von Braun 2013 <sup>[[#fn:r60|60]]</sup> ; Coates 2013 <sup>[[#fn:r61|61]]</sup> ; Puma et al. 2015 <sup>[[#fn:r62|62]]</sup> ; Deryng et al. 2014 <sup>[[#fn:r63|63]]</sup> ; Harvey et al. 2014b <sup>[[#fn:r64|64]]</sup> ; Iizumi et al. 2013 <sup>[[#fn:r65|65]]</sup> ; Seaman et al. 2014 <sup>[[#fn:r66|66]]</sup> ) (Sections 5.3.2, 5.3.3, 5.6.2 and 5.7.1). While international trade in food is assumed to be a key response for alleviating hunger, historical data and economic models suggest that international trade does not adequately redistribute food globally to offset yield declines or other food shortages when weather extremes reduce crop yields ( ''medium confidence'' ) (Schmitz et al. 2012 <sup>[[#fn:r67|67]]</sup> ; Chatzopoulos et al. 2019 <sup>[[#fn:r68|68]]</sup> ; Marchand et al. 2016 <sup>[[#fn:r69|69]]</sup> ; Gilbert 2010 <sup>[[#fn:r70|70]]</sup> ; Wellesley et al. 2017 <sup>[[#fn:r71|71]]</sup> ). When droughts, heat waves, floods or other extremes destroy crops, evidence has shown that exports are constrained in key producing countries contributing to price spikes and social tension in importing countries which reduce access to food ( ''medium evidence, medium agreement'' ) (von Uexkull et al. 2016 <sup>[[#fn:r72|72]]</sup> ; Gleick 2014 <sup>[[#fn:r73|73]]</sup> ; Maystadt and Ecker 2014 <sup>[[#fn:r74|74]]</sup> ; Kelley et al. 2015 <sup>[[#fn:r75|75]]</sup> ; Church et al. 2017 <sup>[[#fn:r76|76]]</sup> ; Götz et al. 2013 <sup>[[#fn:r77|77]]</sup> ; Puma et al. 2015 <sup>[[#fn:r78|78]]</sup> ; Willenbockel 2012 <sup>[[#fn:r79|79]]</sup> ; Headey 2011 <sup>[[#fn:r80|80]]</sup> ; Distefano et al. 2018 <sup>[[#fn:r81|81]]</sup> ; Brooks 2014 <sup>[[#fn:r82|82]]</sup> ). There is little understanding of how food system shocks cascade through a modern interconnected economy. Reliance on global markets may reduce some risks, but the ongoing globalisation of food trade networks exposes the world food system to new impacts that have not been seen in the past (Sections 5.1.2, 5.2.1, 5.5.2.5, 5.6.5 and 5.7.1). The global food system is vulnerable to systemic disruptions and increasingly interconnected inter-country food dependencies, and changes in the frequency and severity of extreme weather events may complicate future responses (Puma et al. 2015 <sup>[[#fn:r83|83]]</sup> ; Jones and Hiller 2017 <sup>[[#fn:r84|84]]</sup> ).

Impacts of climate change are already detectable on food supply and access as price and trade reactions have occurred in response to heatwaves, droughts and other extreme events ( ''high evidence, high agreement'' ) (Noble et al. 2014 <sup>[[#fn:r85|85]]</sup> ; O’Neill et al. 2017b <sup>[[#fn:r86|86]]</sup> ). The impact of climate change on food stability is underexplored (Schleussner et al. 2016 <sup>[[#fn:r87|87]]</sup> ; James et al. 2017 <sup>[[#fn:r88|88]]</sup> ). However, some literature assesses that by about 2035, daily maximum temperatures will exceed the 90th percentile of historical (1961–1990) temperatures on 25–30% of days (O’Neill et al. 2017b <sup>[[#fn:r89|89]]</sup> , Figures 11–17) with negative shocks to food stability and world food prices. O’Neill et al. (2017b) <sup>[[#fn:r90|90]]</sup> remark that in the future, return periods for precipitation events globally (land only) will reduce from one-in-20-year (historical) to about one-in-14- year or less by 2046–2065 in many areas of the world. Domestic efforts to insulate populations from food price spikes associated with climatic stressors in the mid-2000s have been shown to inadequately shield from poverty, and worsen poverty globally (Diffenbaugh et al. 2012 <sup>[[#fn:r91|91]]</sup> ; Meyfroidt et al. 2013 <sup>[[#fn:r92|92]]</sup> ; Hertel et al. 2010 <sup>[[#fn:r93|93]]</sup> ). The transition to high risk is estimated to occur around 1.4°C, possibly by 2035, due to changes in temperature and heavy precipitation events ( ''medium confidence)'' (O’Neill et al. 2017b <sup>[[#fn:r94|94]]</sup> ; Fritsche et al. 2017a <sup>[[#fn:r95|95]]</sup> ; Harvey et al. 2014b <sup>[[#fn:r96|96]]</sup> ). ''Very high risk'' may occur by 2.4°C ( ''medium confidence'' ) and 4°C of warming is considered catastrophic (IPCC 2018c <sup>[[#fn:r97|97]]</sup> ; Noble et al. 2014 <sup>[[#fn:r98|98]]</sup> ) for food stability and access because a combination of extreme events, compounding political and social factors, and shocks to crop yields can heavily constrain options to ensure food security in import- reliant countries.

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