Rice Yields Fall As Temperatures Rise

WASHINGTON, Aug. 10 (UPI) — Rice yields in many parts of Asia have been falling with global warming, and more declines are to come, U.S. researchers say.

Scientists studying records from 227 farms in six important rice-producing countries including Thailand, Vietnam, India and China say yields have fallen 10 percent to 20 percent in the last 25 years in some locations, the BBC reported.

In another study researchers found that rice yields in the Philippines were dropping by 10 percent for every 2-degree F increase in nighttime temperatures.

The latest data comes from rice-growing lands of Asia from the Indian state of Tamil Nadu to the outskirts of Shanghai.

“We found that as the daily minimum temperature increases, or as nights get hotter, rice yields drop,” lead researcher Jarrod Welch said.

The exact reason is not clear, scientists say, but may involve rice plants having to respire more during warm nights, expending more energy without being able to photosynthesize.

A report by the Intergovernmental Panel on Climate Change concluded that for “temperature increases more than 3 C (5 degrees F), average impacts are stressful to all crops assessed and to all regions.”

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