Southwest may face 'megadrought' within century

Due to global warming, scientists say, the chances of the southwestern United States experiencing a decadelong drought is at least 50 percent, and the chances of a "megadrought" - one that lasts up to 35 years - ranges from 20 to 50 percent over the next century. The study by Cornell, University of Arizona and U.S. Geological Survey researchers will be published in a forthcoming issue of the American Meteorological Society's Journal of Climate. "For the southwestern U.S. I'm not optimistic about avoiding real megadroughts," said Toby Ault, Cornell assistant professor of earth and atmospheric sciences and lead author of the paper. "As we add greenhouse gases into the atmosphere - and we haven't put the brakes on stopping this - we are weighting the dice for megadrought." As of Aug. 12, most of California sits in a D4 "exceptional drought," which is in the most severe category. Oregon, Arizona, New Mexico, Oklahoma and Texas loiter in a substantially less severe D1 moderate drought. Ault says climatologists don't know whether the severe western and southwestern drought will continue, but "with ongoing climate change, this is a glimpse of things to come.