In a new study published today in Nature Climate Change, scientists show how specific wave patterns in the jet stream strongly increase the chance of co-occurring heatwaves in major food producing regions of Northern America, Western Europe and Asia. Their research finds that these simultaneous heatwaves significantly reduce crop production across those regions, creating the risk of multiple harvest failures and other far-reaching societal consequences, including social unrest.

Lead author, Dr Kai Kornhuber from the University of Oxford’s Department of Physics and Colombia University’s Earth Institute, said: “Co-occurring heatwaves will become more severe in the coming decades if greenhouse gases are not mitigated. In an interconnected world, this can lead to food price spikes and have impacts on food availability even in remote regions not directly affected by heatwaves.

“We found a 20-fold increase in the risk of simultaneous heatwaves in major crop producing regions when these global scale wind patterns are in place. Until now this was an underexplored vulnerability in the food system. We have found that during these events there actually is a global structure in the otherwise quite chaotic circulation. The bell can ring in multiple regions at once and the impacts of those specific interconnections were not quantified previously.”

Western North America, Western Europe and the Caspian Sea region are particularly susceptible to these atmospheric patterns that get heat and drought locked into one place simultaneously where they then affect crops production yields.

Read more at University of Oxford