Bloomberg-Businessweek

By Karen Weise
September 04, 2014

The drought in California has already devastated the environment and upended the state’s economy. Imagine if it were to last for a decade. Or four decades. Or longer. So-called megadroughts are increasingly likely as the earth warms, according to a new scientific paper that paired historic drought patterns with climate change models.

Toby Ault, an assistant professor at Cornell University and lead author of the study, said he and co-authors from the University of Arizona and the U.S. Geological Survey suspected that climate change would “load the dice” and make megadroughts more common, but they didn’t know by how much. So they took past drought patterns, documented through tree rings and other assessments, and then simulated the impact of global warming based on three scenarios for each of the 27 predictive models of climate change compiled by the Lawrence Livermore National Laboratory. The results will be published in the American Meteorological Society’s Journal of Climate.

Once or twice a century, the U.S. has seen a roughly decade-long drought, such as the one that created the Dust Bowl in the 1930s and another in the 1950s that severely parched the Midwest and Texas. Historically, there has been less than a 50 percent likelihood of a prolonged drought occurring in any given 10-year period. But when the researchers factored in the changes in precipitation that are anticipated by the climate change models, the likelihood of a decade-long drought jumped more than 90 percent in some areas.

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