Rothamsted warns of climate change threat to wheat yields

Short, intense periods of heat and drought during wheat flowering could become one of the biggest threats to global wheat production in the coming decades, according to a new study from Rothamsted Research.

Using advanced climate projections and the Sirius wheat model, scientists estimated how brief heatwaves and droughts at flowering may affect future yields.

They found that by 2050, global yield losses linked to extreme heat at flowering could rise by about one-third, and by 2090 by more than three-quarters.

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Dr Mikhail Semenov, mathematical modeller and emeritus fellow at Rothamsted Research, said: “Flowering is one of the most sensitive stages in wheat development.

“It’s when the plant sets grain, which ultimately determines yield.”

He added that even a few days of very high temperatures or severe water stress at flowering can reduce grain numbers and significantly cut final harvests.

From drought to heat risk

Currently, drought during flowering causes more yield loss than heat. However, its overall global impact is expected to decline slightly in the future.

In contrast, heat stress during flowering is expected to become significantly more harmful.

Prof Malcolm Hawkesford, leader of the “Delivering Sustainable Wheat” Institute Strategic Programme at Rothamsted Research, added: “This kind of modelling provides critical information on, and pointers to, the traits we should be breeding for now, ready for predicted future climate conditions.”

Building resilient wheat systems

Preparing for heat stress and drought will be key to maintaining stable wheat production in the decades ahead, helping prevent food insecurity amid rising global demand for wheat.

By understanding when crops are most vulnerable, farmers and researchers can work together to develop more resilient systems, Rothamsted Research said.

It therefore recommends that farmers choose varieties with improved tolerance to heat and drought, adjust sowing dates and management to reduce the chance of flowering during peak heat, and stay informed about local climate trends and seasonal forecasts.

Plant breeders, it suggests, should place greater emphasis on developing wheat varieties that can withstand short bursts of high temperature during flowering.