September 26, 2023

The world’s wheat supply is at risk of a dangerous shock from heat and drought, study warns

Extreme heatwaves and droughts caused by climate change could shock global food supplies and drive up prices, according to a new study.

The research, published Friday in the journal npj Climate and Atmospheric Science, assesses a worst-case scenario in which extreme weather hits two granary regions in the same year, affecting winter wheat crops in both the U.S. Midwest and northeast China.

Winter wheat is planted in the fall, dormant in the winter cold, and then harvested in early summer. The study found that the extreme weather conditions that would push those wheat crops beyond their physiological tolerances are increasingly likely. If such weather were to hit multiple regions at once — a scenario possible in today’s climate — the global food system could be strained in dangerous ways.

Erin Coughlan de Perez, the study’s lead author and a climate scientist and associate professor at Tufts University, said the study was designed to show political leaders and disaster response professionals the extent to which a critical crop is threatened so they can prepare for it. such a crisis situation.

“We suffer from a lack of imagination in terms of what this could look like,” Coughlan de Perez said. “The whole point of imagining these dire impacts — we could take action to prevent them and build a more resilient system.”

Already, climate change is disrupting food production around the world. The Horn of Africa, for example, suffered several years of drought from 2020, killing livestock and wiping out crops. The World Weather Attribution Network determined that climate change was responsible for that drought, leaving more than 4 million people in need of humanitarian assistance.

This year, latter rain in China’s largest wheat-producing province, Henan, is complicating efforts to harvest grain already damaged by wet weather, Reuters reported.

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

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

In the new study, Coughlan de Perez and her collaborators ran climate models for the Midwest and Northeast of China, then compared the results to known physiological tolerances of the winter wheat grown in those regions.

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

The climate models showed that heat waves that were expected to hit the Midwest in just 1 in 100 years in 1981 are now likely to hit every six years. Northeast China is now expected to experience a heat wave of 1 in 100 years every 16 years.

Such intense heat can cause crop failures.

“Physiologically, if we get heat waves that are unprecedented and bigger than anything we’ve seen in the past, it could be devastating to wheat crops,” Coughlan de Perez said. She added that these two major agricultural areas have never experienced temperatures as high — or damaging — as the climate models allow.

“Places that have not experienced an extreme event or disaster recently are places that are probably not preparing for it,” she said.

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

The new research provides “a solid and sound way to evaluate threats to our food system that are beyond the scope of the historical record,” said Anderson, who was not involved in the study.

While the climate models used in the study didn’t find a strong connection between heat wave patterns in the Midwest and northeast China, Coughlan de Perez said it’s possible that such events could overlap in the same year.

That would increase the supply of wheat to the crater and raise prices. According to the Ministry of Agriculture, China produced about 17% of the world’s wheat by 2022. The US produced about 6%, mostly from the Midwest.

Wheat imports are critical to the diet in many countries. That reality became particularly apparent during the Russian invasion of Ukraine early last year, which disrupted wheat exports from both countries. Together they were responsible for about a third of global wheat exports. Prices soared, prompting fears of impending hunger and famine in many African and Middle Eastern countries that depend on those wheat supplies. However, the worst effects of the wheat crisis were averted 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 synthesis of climate impacts, the sixth report of its kind, predicts that the risk of hunger will increase over time. The diverse effects of climate change could hamper the production of staple crops such as rice, wheat, soybeans and corn, and the likelihood of simultaneous crop failures will increase, the report said.

However, other recent studies suggest that certain levels of global warming could actually increase overall global wheat yields, Anderson said. That’s because climate change could shift the regions where wheat can be grown, and an increase in carbon dioxide could increase photosynthesis and production. But bus years are also becoming more likely, the same studies suggest.

Still other research suggests that some growers’ efforts to improve wheat breeding may not be keeping up with the rate at which the climate is warming.

“We need to consider these kinds of threats and t
he possibility that extreme climate events will lead to more frequent shocks on a global scale, even for these crops where we expect average yields to increase,” Anderson said.

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