The Heat Is Online

Study: U.S. Agriculture At Risk From Changing Climate

Study: Climate Change Threatens U.S. Farms

Discover,Com, Oct. 29, 2003

The closest look yet at climate change in the United States predicts trouble for many U.S. farmers.

A new study by a broad group of researchers breaks the geography of the United States into smaller pieces to see a finer scale of changes that would likely occur if carbon dioxide -- a global warming gas -- continues on its course toward doubling by the year 2060. The picture isn't entirely rosy.

"We're finding that (the finer model) certainly made a bigger difference than expected," said Linda Mearns, lead investigator on the project at the National Center for Atmospheric Research.

"Agriculture didn't do as well."

Among the predictions of the closer look are better than expected increases in corn production in the Northern Plains, but worse than expected in productivity through the Midwest's Corn Belt and Southeast. The study appears in the current issue of the journal Climatic Change.

In the Southeast the model shows a whopping one-third loss to the agricultural economy if farmers don't prepare for climate change  and a one-fifth loss even if they do change crops to reflect warmer conditions. Cotton will thrive under the warmer climate, but other crops will have a harder time of it in that part of the United States.

In all, five out of the ten agricultural regions in the United States came out worse when the climate changes were fed into an economic model. That drops a $3 billion benefit previously predicted by coarser models just a tenth as much: $300 million.

Earlier coarse models of climate change in the United States typically divide the planet up into grid with squares 186 miles across. The new model divided just the contiguous 48 U.S. states into grids 31 miles across -- and so it takes into account local features like coastlines and mountain ranges like the Appalachians that are often glossed over by the coarser models, said Ruby Leung, a climate modeler at the Pacific Northwest National Laboratory.

The finer model depended on a coarser model to connect it to ongoing land, air and ocean changes over the rest of the planet over the same six decades.

"What we want to study are the effects of climate change on crops, water, forests. Fish and now the EPA wants to look at air quality," Leung said. That even finer picture, she explained, takes a lot of expertise in a lot of areas as well as a lot of computer power to chug through all the information and create a meaningful picture.