Giant waves in the jet stream threaten global food production

Dec. 9 (UPI) — Unique atmospheric wave patterns in the jet stream increase the odds of multiple global heatwaves happening at once, threatening global food security, according to a new study published in the journal Nature Climate Change.

When multiple heatwaves strike different agricultural regions at the same time, global food production can take a hit, increasing the risk of food price hikes. Especially devastating co-occurring heatwaves can trigger widespread crop failures, causing starvation and social unrest.

When scientists studied atmospheric conditions during periods characterized by simultaneous heatwaves, they found a unique wave pattern propagating throughout the jet stream.

“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,” lead study author Kai Kornhuber, a physicist with the University of Oxford and Colombia University’s Earth Institute, said in a news release. “Until now, this was an under-explored vulnerability in the food system.”

Normally, waves in the jet stream look ungoverned by cohesive logic. But researchers were able to locate atmospheric wave patterns linking disparate climate regions.

“We have found that during these events there actually is a global structure in the otherwise quite chaotic circulation,” Kornhuber said. “The bell can ring in multiple regions at once and the impacts of those specific interconnections were not quantified previously.”

The new analysis showed agricultural regions in Western North America, Western Europe and those surrounding the Caspian Sea are especially vulnerable to co-occurring heatwaves. The research also confirmed that the newly identified wave patterns are linked with depressed crop yields.

“During years in which two or more summer weeks featured the amplified wave pattern, cereal crop production was reduced by more than 10 percent in individual regions, and by 4 percent when averaged across all crop regions affected by the pattern,” said study co-author Elisabeth Vogel from Melbourne University.

Researchers aren’t yet sure what causes the jet stream to adopt the unique wave patterns, but hope climate models can updated to account for the phenomena.

“If climate models are unable to reproduce these wave patterns, risk managers such as reinsurers and food security experts may face a blind spot when assessing how simultaneous heat waves and their impacts could change in a warming climate,” said study co-author Radley Horton, researcher with the Lamont-Doherty Earth Observatory at Colombia University.

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