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"The simulations with the multi-crop models showed that warming is already slowing yield gains, despite observed yield increases in the past, at a majority of wheat-growing locations across the globe," says Senthold Asseng. (Credit: Krišjānis Kamradzis/Flickr)

climate change

Hotter climate could ‘wilt’ wheat crops

A new combination computer model more accurately predicts just how much trouble a warming climate could mean for the world’s wheat crop.

For every degree Celsius that the temperature increases, the world stands to lose 6 percent of its wheat crop. That’s one-fourth of the annual global wheat trade, which reached 147 million tons in 2013.

“We started this with wheat, as wheat is one of the world’s most important food crops,” says Senthold Asseng, professor of agricultural and biological engineering at University of Florida.

“The simulations with the multi-crop models showed that warming is already slowing yield gains, despite observed yield increases in the past, at a majority of wheat-growing locations across the globe.”

Wheat predictions

Global food production needs to grow 60 percent by 2050 to meet the projected demand from an anticipated population of more than 9 billion people. That’s a huge agricultural challenge, complicated by temperature increases due to climate change, Asseng says.

For 20 years, scientists have been trying to estimate the effects of temperature increase and climate change on various crops and on wheat production, which accounts for 20 percent of calories consumed globally.

But different research groups came up with different results.

By pooling models, as part of the global Agricultural Model Intercomparison and Improvement Project (AgMIP), scientists found they can better predict the impact of higher temperatures on wheat yield, Asseng says.

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For the study, published in Nature Climate Change, researchers devised an ensemble of computer models to increase the accuracy of their predictions. They worked with 30 wheat crop models and tested them against field experiments. In those experiments, average season temperatures ranged from 15 to 32 degrees Celsius (59 to 89.6 degrees Fahrenheit).

The ensemble of models consistently simulated crop temperature responses more accurately than did any single model.

In the past 100 years, global temperatures have risen by more than 0.6 degrees and are projected to increase by 2 to 4 degrees Celsius by the end of the century, according to the International Panel on Climate Change.

New heat-tolerant wheat cultivars and crop management are needed to counteract the projected yield decline, and crop models will play a major role in developing new research strategies for that, Asseng says.

Researchers from University of Bonn in Germany and the French national research institute INRA contributed to the study.

Source: University of Florida

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