Study confirms climate model predictions of more severe droughts in the U.S.

E&E  • Posted: Thursday, August 16, 2012

A study published in the journal Nature Climate Change confirms what climate models have previously predicted: Drought will become more severe in the United States in the coming decades, and climate change will amplify drought frequency and intensity.

Climate models have predicted more severe and widespread droughts, but these conclusions had been questioned because the models did not use historical data on drought patterns.

Aiguo Dai, the study’s author and a researcher at the National Center for Atmospheric Research, found that the models were accurate by using a statistical method with data about sea surface temperatures.

“We can now be more confident that the models are correct,” Dai said, “but unfortunately, their predictions are dire.”

The main driver of drought in the United States currently is sea surface temperatures in the Pacific Ocean, which in a cold period can decrease precipitation, especially in the western part of the country.

Pacific sea surface temperatures are in a cold phase that may last for another decade or two. While that oscillation between cold and warm sea surface temperatures affects precipitation, global warming will increase evaporation over land.

Additionally, Dai predicts more dryness in South America, southern Europe and Africa (Hristio Boytchev, Washington Post, Aug. 13). — RE