US could be facing the worst droughts in history - Irish Independent

Darryl Fears

Published 14/02/2015 | 02:30

A man carries drinking water as water wells supplying hundreds of residents remain dry in the fourth year of worsening drought in East Porterville, California.

Long-lasting mega-droughts could occur with increasing frequency in the western United States later this century if no action is taken to rein in climate change by curbing fossil fuel use, according to researchers.

Mega-drought is defined as any drought as bad as the worst already seen in the 20th century, but lasting much longer, for 35 years or more. The study is the first to predict that the coming intense dry spells could exceed the decades-long mega-droughts that occurred centuries ago and are blamed for the demise of certain civilisations in the late 13th century.

"I was honestly surprised at just how dry the future is likely to be," said co-author Toby Ault, an assistant professor in the Department of Earth and Atmospheric Sciences at Cornell University.

Concern

"I look at these future mega-droughts like a slow moving natural disaster. We have to put mega-droughts into the same category as other natural disasters that can be dealt with through risk management."

The risks and dangers are worse today because of the larger population and greater dependence on water resources, scientists warned.

"We are the first to do this kind of quantitative comparison between the projections and the distant past, and the story is a bit bleak," said Jason Smerdon, a co-author and climate scientist at the Lamont-Doherty Earth Observatory, part of the Earth Institute at Columbia University.

"Even when selecting for the worst mega-drought-dominated period, the 21st century projections make the mega-droughts seem like quaint walks through the Garden of Eden."

"The results... are extremely unfavourable for the continuation of agricultural and water resource management as they are currently practiced in the Great Plains and southwestern United States," said David Stahle, professor in the Department of Geosciences at the University of Arkansas, who was not involved in the study.

Currently the western United States has been experiencing a drought for about 11 of the past 14 years.

Irish Independent