Climate change increases possibility of megadrought in Southwestern U.S.
NEW YORK – “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 conditions.”
As of mid-August, most of California sits in a D4 “exceptional drought,” which is in the most severe category. Oregon, Arizona, New Mexico, Oklahoma and Texas also loiter between moderate and exceptional drought. Ault says climatologists don’t know whether the severe western and southwestern drought will continue, but he said, “With ongoing climate change, this is a glimpse of things to come. It’s a preview of our future.”
Ault said that the West and Southwest must look for mitigation strategies to cope with looming long-drought scenarios. “This will be worse than anything seen during the last 2,000 years and would pose unprecedented challenges to water resources in the region,” he said.
In computer models, while California, Arizona and New Mexico will likely face drought, the researchers show the chances for drought in parts of Washington, Montana and Idaho may decrease.
Beyond the United States, southern Africa, Australia and the Amazon basin are also vulnerable to the possibility of a megadrought. With increases in temperatures, drought severity will likely worsen, “implying that our results should be viewed as conservative,” the study reports.
“These results help us take the long view of future drought risk in the Southwest – and the picture is not pretty. We hope this opens up new discussions about how to best use and conserve the precious water that we have,” said Julia Cole, UA professor of geosciences and of atmospheric sciences.
The study, “Assessing the Risk of Persistent Drought Using Climate Model Simulations and Paleoclimate Data,” was also co-authored by Julia E. Cole, David M. Meko and Jonathan T. Overpeck of University of Arizona; and Gregory T. Pederson of the U.S. Geological Survey.
The Southwestern United States could face a decade long drought according to a new study by Cornell, University of Arizona and U.S. Geological Survey researchers. According to lead author and Cornell assistant professor of earth and atmospheric sciences Toby Ault, climate change is increasing the possibility of a “megadrought” – a drought that could last over thirty years.
Toby Ault, Assistant Professor of Earth and Atmospheric Sciences at Cornell University states, “The risk of a decade long drought is normally about 50 per cent but with climate change it goes up to about 80 or 90 per cent according to our results. And for a multiple decade long drought, a megadrought, the risk is usually in the order of 5 to 15 per cent but with climate change it goes up to between 20 and 50 percent for a lot of the Southwest.”
The study is based on historical data of previous droughts and uses current changes in precipitation patterns caused by global warming.