According to a new collaborative study released this week by a group of international scientists, the production of rice will be hindered as temperatures increase in rice-growing areas from global warming.

According to the Food and Agriculture Organization of the United Nations, the research team found evidence that the net impact of projected temperature increases will be to slow the growth of rice production in Asia. Rising temperatures during the past 25 years have already cut the yield growth rate by 10-20 percent in several locations.

The study was published in the Proceedings of the National Academy of Sciences (PNAS), a peer-reviewed, scientific journal circulated in the United States.

“We found that as the daily minimum temperature increases, or as nights get hotter, rice yields drop,” said lead author of the report and graduate student of economics at the University of California at San Diego, Jarrod Welch.

Scientistis analyzed 6 years of data taken from 227 irrigated rice farms in six major rice-growing countries on the Asian continent, which produces more than 90 percent of the world’s rice.

The study marks the first time scientists have investigated the impact of temperature change in both tropical and subtropical regions on irrigated rice production in farmer-managed rice fields in Asia.

“Up to a point, higher day-time temperatures can increase rice yield, but future yield losses caused by higher night-time temperatures will likely outweigh any such gains because temperatures are rising faster at night,” said Welch. “And if day-time temperatures get too high, they too start to restrict rice yields, causing an additional loss in production.”

According to Welch, the study is unique as it uses data collected in real-world circumstances.  All data was collected from functioning farmers’ fields, which makes results potentially different than those found in controlled experimental settings.

“Farmers can be expected to adapt to changing conditions, so real-world circumstances, and therefore outcomes, might differ from those in controlled experimental settings,” said Welch.

According to researchers, a decline in rice production would quickly lead to more people living under the poverty line.  Rice is consumed by around three billion people each day.  Almost 60 percnt of the world’s one billion poorest and malnourished people living in Asia depend on rice as their staple food.

“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. This will get increasingly worse as temperatures rise further towards the middle of the century,” Welch said.

Photo:  Rice fields, Sapa, Vietnam.  Photo by Suzanne Schreck