Scientists predict US climate collapse with winter wheat

Increasing heatwaves will also hurt Chinese winter wheat producers, researchers warn.

The world is getting hotter, causing shifts in seasonal patterns and an increase in extreme weather events such as severe droughts and heat waves that can affect crop yields and food supplies.

A recent study by a researcher at the School of Nutrition Science and Policy Friedman at Tufts University found that the likelihood of extreme temperatures that could affect yields increased significantly in winter wheat-growing regions of the US and China.

“The findings predict that heatwaves, which used to happen about once every hundred years, are now likely to occur once every 6 years in the US Midwest and once every 16 years in Northeast China. We are already living in a changed climate, although people still tend to underestimate the risks of extreme events,” said lead author Erin Coughlan de Perez.

According to the latest report from the Intergovernmental Panel on Climate Change, global mean surface temperatures over the past decade have been 1.1 degrees Celsius warmer than between 1850 and 1900.

Perez and her colleagues have collected a large amount of seasonal forecast data over the past 40 years to use a method known as the Unprecedented Simulated Extreme Ensemble or UNSEEN approach to estimate the likely frequency of extreme temperatures that exceed critical growth thresholds for winter wheat.

Winter wheat is sown in the fall for harvest the following summer, when the plants resume vegetation in the spring. High temperatures in the spring during the flowering of winter wheat have negative consequences, but in any case, at temperatures above 27.8 degrees Celsius, the crop falls into heat stress, and at temperatures above 32.8 degrees Celsius, important enzymes in wheat begin to break down.

“We used to have seasons in the US Midwest where, on average, we were four or five days above the threshold for enzyme breakdown. In our study, the forecasts showed possible alternative realities of today's climate, when this threshold reaches 15 days with the most devastating consequences. Record heat is forecast to go hand in hand with record drought, a highly dangerous combination especially for winter wheat in the US and China going forward, although both regions have been lucky in recent years. Weather has an aspect of chance, like a game of dice. But if you were lucky once, it does not mean that luck will always be on your side. Climate change is a strong player to be reckoned with. We have identified regional and global atmospheric circulation patterns that could result in very hot and dry events, including a possible worst case scenario where US and Chinese wheat production is severely affected in the same season. The results of the work can help develop plans for climate change adaptation in these regions and ensure that the agro-industrial complex has time to prepare for the upcoming unprecedented events,” concludes Erin Coughlan de Perez.