Temperature increases could slow rice production, study says

A study published online Monday in Proceedings of the National Academy of Sciences found that anticipated temperature increases "could slow the growth of rice production unless farmers adapt by changing management practices and switch to more heat-tolerant varieties," Reuters reports (Fogarty, 8/10).

"This is the latest in a line of studies to suggest that climate change will make it harder to feed the world's growing population by cutting yields," BBC writes (Black, 8/9).

For the study, researchers "looked at the impact of rising daily minimum and maximum temperatures on irrigated rice production between 1994-1999 in 227 fields in China, India, Indonesia, the Philippines, Thailand and Vietnam," Agence France-Presse writes (8/9). Though increases in daytime temperatures can increase rice yields, "higher nighttime temperatures have a negative effect," the Associated Press notes. The University of California, San Diego's Jarrod Welch, who led the study, said nighttime temperatures are going up faster than daytime temperatures and would result in a net loss in productivity, the news service writes.

"If we cannot change our rice production methods or develop new rice strains that can withstand higher temperatures, there will be a loss in rice production over the next few decades as days and nights get hotter," Welch explains in the study. "This will get increasingly worse as temperatures rise further towards the middle of the century," he added. According to the researchers, slower rice production could increase poverty and hunger (8/9).

The study, which included researchers from the International Rice Research Institute in the Philippines and the U.N.'s Food and Agriculture Organization, also found that "rising temperatures during the past 25 years have already cut the yield growth rate by 10-20 percent in several locations in the study areas," according to Reuters. In some cases, farmers could adapt by shifting the time of the main growing season, Welch said. "There's also the possibility that areas where rice is currently grown becomes too warm and production shifts to cooler areas," he added (8/10).