World wheat supply at risk of dangerous shock from heat and drought, study warns

Extreme heat waves and drought due to climate change have the potential to shock global food supplies and send prices soaring, according to a new study.

The research, published on Friday in the npj journal Climate and Atmospheric Science, assesses the worst-case scenario in which extreme weather hits two bread-producing regions in the same year, hurting winter wheat crops in the U.S. Midwest and the United States. northeast China.

Winter wheat is planted in the fall, lies dormant in the winter cold, and then harvested in early summer. The study found that extreme weather conditions that would push these wheat crops beyond their physiological tolerances are becoming more likely. If this weather were to affect multiple regions at the same time – a possible scenario in the current climate – it could stress the global food system in dangerous ways.

Erin Coughlan de Perez, lead author of the study, a climate scientist and associate professor at Tufts University, said the research aims to show political leaders and disaster response teams the degree to which a critical culture is threatened, so they can adequately prepare for such a crisis.

“We are suffering from a lack of imagination in terms of what this could look like,” said Coughlan de Perez. “The goal of imagining these serious consequences – we could take steps to avoid them and build a more resilient system.”

Climate change is already disrupting food production around the world. The Horn of Africa, for example, has suffered several years of drought starting in 2020, which has killed livestock and destroyed crops. The World Weather Attribution Network determined that climate change was responsible for this drought, which left more than 4 million people in need of humanitarian assistance.

This year, late rains in China’s biggest wheat-producing province, Henan, are complicating efforts to harvest grain already damaged by wet weather, Reuters reported.

Harvesting Wheat in Sihong County SIHONG, CHINA - JUNE 01: Aerial view of combine harvesters working in a field during wheat harvest season on June 1, 2021 in Sihong County, Suqian City, Jiangsu Province, China China.  (Zhang Lianhua/VCG via Getty Images archive)

Harvesting Wheat in Sihong County SIHONG, CHINA – JUNE 01: Aerial view of combine harvesters working in a field during wheat harvest season on June 1, 2021 in Sihong County, Suqian City, Jiangsu Province, China China. (Zhang Lianhua/VCG via Getty Images archive)

In the new study, Coughlan de Perez and his collaborators ran climate models for the midwest and northeast of China and compared the results with the known physiological tolerances of winter wheat grown in those regions.

High spring temperatures can slow wheat growth and also cause important enzymes in the plant to break down.

Climate models have shown that heat waves that in 1981 were expected to affect the Midwest in just 1 in 100 years are now likely every six years. In northeast China, a 1-in-100-year heat wave is expected to occur every 16 years.

Such severe heat can cause crop failures.

“Physiologically, if we have unprecedented and larger heat waves than we’ve seen in the past, that could be devastating for wheat crops,” said Coughlan de Perez. She added that these two main agricultural areas have never experienced temperatures as high – or harmful – as climate models say is possible.

“Places that haven’t recently experienced an extreme event or disaster are likely to be places that aren’t preparing for one,” she said.

Weston Anderson, an assistant research scientist at the University of Maryland and NASA who specializes in climate impacts on food security, said risks to crucial crops are increasing as the world continues to warm.

The new research offers “a solid, solid way to assess threats to our food system that are beyond the reach of the historical record,” said Anderson, who was not involved in the study.

While climate models used in the research did not find a strong connection between heat wave patterns in the midwest and northeast China, Coughlan de Perez said it’s possible such events could overlap in the same year.

This would cause the wheat supply to decrease and prices to rise. China produced about 17% of the world’s wheat in 2022. The US produced about 6%, much of it from the Midwest, according to the Department of Agriculture.

Wheat imports are essential for nutrition in many countries. That reality was especially clear during the Russian invasion of Ukraine early last year, which disrupted wheat exports from both countries. Together they accounted for about a third of global wheat exports. Prices soared, giving rise to fears of impending famine and starvation in many African and Middle Eastern countries that depend on these wheat supplies. The worst consequences of the wheat crisis were averted, however, when the warring countries reached an agreement allowing Ukraine to export grain.

The new study is far from the first to warn of the threat of climate change to our food supply. The UN Intergovernmental Panel on Climate Change’s recent summary of climate impacts, its sixth report, predicts that the risk of famine will increase over time. The various impacts of climate change could harm the production of staple crops such as rice, wheat, soybeans and corn, and the chance of simultaneous crop failures will increase, says the report.

However, other recent studies suggest that certain levels of global warming may actually increase global wheat yields, according to Anderson. That’s because climate change can change the regions where wheat can be grown, and increased carbon dioxide can increase photosynthesis and production. But bankruptcy years are also becoming more likely, the same studies suggest.

Still other research suggests that some farmers’ efforts to improve wheat breeding may not keep up with how quickly the climate is warming.

“We must consider this type of threat and the possibility that extreme weather events are leading to more frequent shocks on a global scale, even for those crops where we expect average yields to be increasing,” Anderson said.

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