A study suggests that climate change might result in increased grain price volatility and reduced food security. Volatility in the global grain market creates uncertainty for farmers and agribusinesses and can lead to price spikes that reduce access to food. Climate-induced production shocks are a major contributor to market volatility. Michelle Tigchelaar and colleagues estimated the probability of such shocks in maize production under future climate warming using empirical models of the relationship between climate and crop yields. Under 2 °C of global warming, estimated mean yields declined, whereas yield variability increased worldwide, particularly in the United States, eastern Europe, and southern Africa. The top four maize-exporting countries--the United States, Brazil, Argentina, and Ukraine--collectively account for 87% of global maize exports. At present, the probability of all four of these countries experiencing simultaneous yield losses greater than 10% of the present-day mean yield is negligible. However, the authors estimate that the probability of such simultaneous losses might increase to 7% under 2 °C warming and to 86% under 4 °C warming, leading to a higher frequency of international price spikes. According to the authors, the results emphasize the importance of both aggressive carbon dioxide emissions mitigation and breeding crops for improved heat tolerance.
Article #17-18031: "Future warming increases probability of globally synchronized maize production shocks," by Michelle Tigchelaar, David S. Battisti, Rosamond L. Naylor, and Deepak K. Ray.
MEDIA CONTACT: Michelle Tigchelaar, University of Washington, Seattle, WA; tel: 808-724-1392; e-mail: < tigchelaar@atmos.uw.edu >
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Proceedings of the National Academy of Sciences