Severe and worsening drought awaits the continental United States and other middle-latitude regions as global warming tightens its grip on the 21st Century, a new study warns.

While public and political attention focuses on temperature change, this new analysis of 22 computer climate models by drought specialist Aiguo Dai at the National Center for Atmospheric Research in Boulder, Colo., suggests that the more dire consequences of our changing climate may be sharp changes in regional precipitation patterns.

“We are facing the possibility of widespread drought in the coming decades, but this has yet to be fully recognized by both the public and the climate change research community,” Dai said in a statement released by NCAR. “If the projections in this study come even close to being realized, the consequences for society worldwide will be enormous.”

As these model-generated maps graphically illustrate, the drying trend already is underway across much of the Western Hemisphere, southern Europe, the Mediterranean, Africa, Eurasia, Southwest Asia and Australia. The maps show a widely recognized indicator known as the Palmer Drought Severity Index. (Click on the image to get a full view of the relentless drying trend the climate models depict for these regions throughout the 21st century.)

Dai is the first to bring regional details and specific numbers to the general observation of the 2007 assessment of the United Nations Intergovernmental Panel on Climate Change that mid-latitude regions will become drier in the years ahead as precipitation zones migrate to higher latitudes.

Another noted climate specialist, Richard Seager, of Columbia University’s Lamont Doherty Earth Observatory, observed: “The term ‘global warming’ does not do justice to the climatic changes the world will experience in the coming decades. Some of the worst disruptions we face will involve water, not just temperature.”

Image credit: Courtesy of University Corporation for Atmospheric Research