Increasing Drought Seen As Temperatures Rise in U.S., Study Says

A comprehensive study of 99 water sub-basins in the United States shows that rising temperatures, which cause more evaporation and reduce soil moisture, will increase the likelihood of drought in many areas of the U.S. Earlier studies have shown that meteorological drought, based on shifting precipitation patterns in a warming world, was likely to affect regions such as the southwestern U.S. But Gary Yohe of Wesleyan University, along with colleagues from MIT and Industrial Economics Inc., looked at the prospects for hydrological drought, which is based on both precipitation and the effects of rising temperatures. Looking at three different CO2 emissions scenarios, Yohe and his colleagues said they were confident that the impacts of hydrological drought on agriculture and water availability would be increasingly negative and widespread as temperatures increase. The southwestern U.S. and Rocky Mountain states are projected to see the largest increases in drought frequency. The study, published in Environmental Research Letters, said that with good planning, these regions should be able to soften the impact of increasing droughts by exploiting excess water storage capacity.