Study Links Climate Change to Changes in Crop Yields

16 May 2011

Kashmiri farmers cut the harvest in Shariefabad near Srinagar, India

This is the VOA Special English Agriculture Report.

A new study says climate change has reduced the world's wheat and maize production. The study says rice and soybean yields have also decreased in some places -- but increased in others. In the words of the researchers: "For soybeans and rice, winners and losers largely balanced out."

The researchers studied climate trends and global crop production from between nineteen eighty and two thousand eight. They found that climate changes "are already exerting a considerable drag on yield growth" and may have affected food prices.

The study used computer models linking crop yields to weather. Yield is the amount produced for each hectare or acre. The researchers compared the results to what the yields might have been without climate changes. They found that corn production decreased by almost four percent and wheat production decreased by five and a half percent.

Warming temperatures were reported in almost all of Europe, much of Asia and some of South America and Africa. During the study period most countries had greater temperature changes from year to year than they have had historically. But the study says the United States was an important exception -- at least so far.

Corn and wheat yields in most of North America remained about the same. Russia's wheat yields decreased the most. The largest loss in corn yields were in China and Brazil.