Study shows role of land use in global warming; turning U.S. forests into farms has cooling effect

Most changes in land use in the U.S. raise regional surface temperatures by reducing vegetative cover, but "Conversion of any land to agricultural use results in cooling, even land that was previously forested," Newswise reports on a study by scientists at the University of Maryland, the University of Colorado and Purdue University.

The study, which will appear in the Royal Meteorological Society’s International Journal of Climatology, is based on "observation minus re-analysis," an approach co-developed by Maryland Professor Eugenia Kalnay. It adds "significant weight to a growing recognition among climate scientists for the need to more fully incorporate land-use change into computer models that are designed to forecast future changes in climate conditions," says Newswise, a research-reporting service. (Map shows variances in degrees Celsius from 1979 to 2003)

"Until recently, human-induced changes (warming) in climate have been viewed by most scientists as primarily the result of increasing concentrations of carbon dioxide and other greenhouse gases," Newswise notes. Now, says Dev Niyogi, a Purdue earth and atmospheric sciences professor and the Indiana state climatologist, "a significant trend, particularly the warming trend in terms of temperatures, can also be partially explained by land-use change." For the Newswise report, go here. For the study, here.