In the coming decades at least one-quarter of the world's wheat production will be lost to extreme weather from climate change if no adaptive measures are taken, according to a recent study.

Researchers at Kansas State University found that wheat yields are projected to decrease by 6 percent for each degree Celsius the temperature rises if no measures to adapt to extreme weather fluctuations are taken.

"It's pretty severe," researcher Vara Prasad said in a statement. "The projected effect of climate change on wheat is more than what has been forecast. That's challenging because the world will have to at least double our food supply in the next 30 years if we're going to feed 9.6 billion people."

Based on the 2012-2013 wheat harvest of 701 million tons worldwide, the resulting temperature increase would result in 42 million tons less produced wheat -- or a loss of nearly one-quarter of the current wheat production.

For the study, researchers systematically tested 30 wheat crop models against field experiments from around the world that were conducted in areas where the average temperature of the growing season ranged from 15 to 32 degrees Celsius.

They found that the effects from climate change and its increasing temperatures on wheat will be more severe than once projected and are happening sooner than expected. While Prasad said increases in the average temperature are problematic, a bigger challenge is the extreme temperatures that are resulting from climate change.

"Extreme temperature doesn't only mean heat; it also means cold," Prasad said. "Simply looking at the average temperature doesn't really show us anything because it's the extremities that are more detrimental to crops. Plants can handle gradual changes because they have time to adapt, but an extreme heat wave or cold snap can kill a plant because that adjustment period is often nonexistent."

Researchers also found that increasing temperatures are shortening the time frame that wheat plants have to mature and produce full heads for harvest, resulting in less grain produced from each plant.

Currently, Prasad and colleagues at Kansas State University, in collaboration with the university's Wheat Genetics Resource Center, are using growth chambers and heats tents to quantify the effects of temperature. The data will help in refining the crop models so that they can be more accurate in predicting wheat responses.

The findings are detailed in the scientific journal Nature Climate Change.