Global warming affecting rice yields

A group of scientists from two universities in the United States, the International Rice Research Institute in the Philippines, and the UN's Food and Agriculture Organization (FAO) recently published the results of a study begun in the 1990s and conducted in over 220 rice farms in China, India, Indonesia, the Philippines, Thailand, and Vietnam.

According to the findings, rising temperatures have caused a decrease in rice yields of between 10 and 20 percent in certain parts of Asia.

"It's not perfectly clear the mechanism which causes this," explained one of the researchers Jarrod Welch.

"One hypothesis is that warmer temperatures increase respiration in the rice plant, which consumes energy. If these warmer temperatures occur at night time, there is no offsetting of the synthesis. So, warmer temperatures mean increased respiration, increased energy consumption in the rice plant. But synthesis is not occurring to replace that energy."

Rice feeds three billion people daily

Rice feeds about three billion people daily across the world and according to FAO figures, over 60 percent of Asia's poor population is dependent on it.

The losses in rice production will lead to food insecurity, experts fear.

David Dawe from the FAO also worked on the study: "If temperatures continue to increase, our research seems to show that rice yields will go down or won't increase as fast as they otherwise would have."

He says this will have an "impact on food prices and make it much more difficult for poor people to afford food. And it's poor people who spend most of their money on rice. So it's they who'll be most affected."

Solutions must be implemented soon

However, Dawe says that there are ways of increasing the rice yields such as creating "better varieties that are more tolerant of higher temperatures, or slow down the increase in temperature, or shift the cropping season, try to plant rice at a different time of year when it's a bit cooler."

Experts have urged politicians to implement these solutions, warning that there could be a serious rice crisis otherwise.

They point out that rising temperatures caused by global warming are one threat to rice yields, but another is rising sea levels which will affect the low-lying rice-growing areas of Asia too.

Author: Pin Manika
Editor: Anne Thomas