Rising Temperatures Reduce Wheat Yields: It Is Not Too Late to Breed New Varieties

If adaptive measures are not taken, for every 1°C rise in temperature in the future, global wheat production could fall by 6%, which would cause a worldwide reduction of 42 million tonnes, equivalent to 1/4 of the current global wheat trade volume.

Wheat plays an important role in feeding the global population. However, global climate change will threaten the wheat harvest. If adaptive measures are not taken, global total wheat production is expected to decline as temperatures rise.

This research result was published in the high-impact journal Nature Climate Change, and the research was completed by an international research team, with the Natural Resources Institute Finland making an outstanding contribution.

The study found that as global climate temperatures rise, grain production in most parts of the world is expected to decline. In 2012, global wheat production was 701 million tonnes, and each 1°C rise in temperature means a worldwide reduction of 42 million tonnes of wheat.

“In 2013, the global wheat trade volume was 147 million tonnes; from another perspective, this figure is equivalent to one quarter of the global wheat trade volume. In addition, the wheat production losses caused by climate change are higher than previously estimated.” pointed out Dr. Reimund R?tter, professor at the Natural Resources Institute Finland. “In fact, predictions should have been made earlier, and should have begun when temperatures rose only slightly.”

When deciding how to take measures to respond to climate change, understanding how different climate factors interact and affect grain production is very crucial.

The researchers conducted field trials and systematically tested 30 different wheat crop growth models. During the growing season, the air temperature in the experimental areas ranged between 15°C and 26°C. Under field experiment conditions, the effect of temperature on yield reduction varied widely. In addition, in some regions, crops increased in years with higher temperatures and decreased in years with lower temperatures, which also increased year-on-year uncertainty.

“From recent years' experience, it can be seen that from an economic perspective, yield variability is very important. It can affect the stability of regional and global wheat supply and food security, and amplify market and price fluctuations.” said Professor Reimund R?tter.

The latest Fifth Assessment Report released by the Intergovernmental Panel on Climate Change predicts that by the end of this century, the global average temperature will rise by 5°C.

“Timely and appropriate response measures, such as breeding more heat-tolerant wheat varieties, may greatly reduce the risk of yield reduction caused by climate change.” Reimund R?tter emphasized.

Researchers from different countries participated in this collaborative study through the Agricultural Model Intercomparison and Improvement Project (AgMIP). AgMIP is integrated and coordinated by Columbia University, the National Aeronautics and Space Administration, and the University of Florida. In this global study, in addition to scientists from Finland, scientists from Germany, France, Denmark, the Netherlands, Spain, the United Kingdom, Colombia, Mexico, India, China, Australia, Canada, and the United States also participated.

In the study setup, the researchers first compared the experimental data of the simulated wheat crop growth models; the experiments included artificial heating and simulated field experiments across multiple regions. The researchers found variations between observations and simulations for individual growth models, and this deviation increased as the growing season temperature rose.

The study's predicted results were obtained through multi-model ensemble calculations. Based on the monitoring results, the scientists then applied multi-model calculations to derive wheat production in the world's major growing regions under conditions of rising temperature.