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.