Within 10 years: rising average temperatures bring worrisome reductions in crop yields

A Warming Climate Could Cause Dramatic Reduction in U.S. Crop Yields, Expert Says
Ryan Rexroth, 6 April 2011

"The current global trend of rising average temperatures could bring worrisome reductions in crop yields within a decade, a leading agricultural economist told a Capitol Hill briefing co-sponsored by AAAS.

Michael J. Roberts, assistant professor of agricultural and resource economics at North Carolina State University, said computer models suggest that average global temperatures will rise enough to cause severe weather extremes that could cut yields by 20% for major crops such as corn and soybeans for the period 2020-2049.

That could happen even with marked reductions in emissions of heat-trapping carbon dioxide (CO2), he said. If those emissions remain on a "business as usual" path, Roberts said, the yield reductions could be as much as 80% for the period 2070-2099."

http://www.aaas.org/news/releases/2011/0406food_and_climate.shtml

"Cereal Killer: Climate Change Stunts Growth of Global Crop Yields

A crop-yield analysis reveals that warming temperatures have already diminished the rate of production growth for major cereal crop harvests during the past three decades
By David Biello | May 5, 2011

The people of the world get 75 percent of their sustenance—either directly, or indirectly as meat—from four crops: maize (corn), wheat, rice and soybeans. The world's rising population—now predicted by the United Nations to reach 10.1 billion by century's end—has been fed thanks to rising yields of all four of these crops during the past century. Humanity's predilection for burning fossil fuels, however, is now contributing to the slowing of such rising yields, cutting harvests of wheat 5.5 percent and maize 3.8 percent from what they could have been since 1980, according to a new analysis of yields."

http://www.scientificamerican.com/article.cfm?id=climate-change-impacts-staple-crop-yields