China food security: wheat crops face ‘unprecedented’ risks as world heats up, study finds

Wheat-producing countries like China must prepare for extreme weather with more heat-tolerant crops to avoid ‘the unimaginable’, researcher says
Underestimating potential for disasters will lead to food shortages, higher prices

Science

Holly Chik

Published: 8:00pm, 2 Jun 2023

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Heatwaves will become more frequent across the globe – a trend that a new climate analysis suggests will have serious implications for countries that produce wheat, including China and the United States.

The shifting seasonal patterns, extreme temperatures and drought that will result from a hotter world will diminish crop yields, an international team of scientists predicts, adding that the world should prepare for food insecurity induced by climate change.

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To mitigate the impact, the research team from Britain, the Netherlands, the US and Zimbabwe has advised that agricultural producers begin planting more heat-tolerant varieties of wheat, while expanding food systems to reduce the possibilities that failures in one region could devastate the world’s food supply.

For comparison, the researchers used data from 1981 to get an accurate picture of the climate changes under way. The analysis showed that heatwaves that were only likely to happen once in around 100 years back then, were now likely to happen once every six years in the US Midwest, and once every 16 years in northeastern China.

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In a worst-case scenario, although unlikely, when wheat production in both China and the US failed in the same season, or at the same time as other staple crops, food prices and availability were likely to be affected globally.

The findings were published in the peer-reviewed research journal npj Climate and Atmospheric Science on Friday.

The growing season for winter wheat crops starts in autumn – they flower in spring and are harvested in the summer. When temperatures exceed 27.8 degrees Celsius (82 Fahrenheit), the plants start to suffer from heat stress. If the temperature rises to 32.8 degrees Celsius, key enzymes start to break down.

In northeastern China, a record-breaking drought event has a 63 per cent chance of also being a record-breaking heat event, where much of the world’s wheat is produced, the study found.

China is the world’s largest consumer and producer of wheat. Last year, the country produced nearly 140 million tonnes of the crop, government data showed.

In recent years, Chinese authorities have stepped up efforts to ensure there is enough food to feed the country’s 1.4 billion people, particularly in the face of global turmoil and events like the war in Ukraine, which affect imports and supply chains.

This week, unusually heavy rain in China prompted local authorities to speed up the harvesting and drying of damaged wheat in a bid to save the crops.

Continuous rain and high humidity across northern China – home to the country’s wheat-production bases in Anhui, Hubei and parts of Shaanxi – have caused sprout damage, known as pre-harvest germination. The wheat has also been infected by plant diseases that can result in higher risks of toxins, thereby limiting end-use applications, such as baking.

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“Collaboration between China and the US can help inspire climate change adaptations and build resilient food systems,” said Erin Coughlan de Perez, an associate professor at the Friedman School of Nutrition Science and Policy at Tufts University in Boston, and lead author of the study.

Coughlan de Perez said the world should prepare to face the risks of food insecurity.

“In the agricultural sector, this means resilient strategies to reduce the impacts of heat and drought on crops, for example, by planting new heat-tolerant wheat varieties,” she said.

“In terms of the wider food system, this means diversification so that a failure in one region is not devastating to the world.”

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She said the effects of climate change were happening in addition to factors like changes to exports that could spark price increases in wheat and potentially lead to food shortages – food insecurity – in the developing world.

“If we only look at the past to understand possible future disasters, we will drastically underestimate current and future risks,” she said.

“We need to use climate science to update our risk perception and to be able to imagine the unimaginable, revealing unprecedented climate events that are possible today which would have dire consequences for agriculture.”

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