Action needed now to prepare for severe drought

Stephen Leahy  in AlertNet via Tierramérica/IPS: Mexico and Central America look like they are covered in dried blood on maps projecting future soil moisture conditions.The results from 19 different state-of-the-art climate models project extreme and persistent drought conditions (colored dark red-brown on the maps) for almost all of Mexico, the midwestern United States and most of Central America.

If climate change pushes the global average temperature to 2.5 degrees Celsius above pre-industrial era levels, as many experts now expect, these regions will be under severe and permanent drought conditions. Future conditions are projected to be worse than Mexico's current drought or the U.S. Dust Bowl era of the 1930s that forced hundreds of thousands of people to migrate.

These are some of the conclusions of the study "Projections of Future Drought in the Continental United States and Mexico", which was published in the December 2011 issue of the American Meteorological Society's Journal of Hydrometeorology and has gone largely unnoticed.

"Drought conditions will prevail no matter what precipitation rates are in the future," said co-author Michael Wehner, a climate scientist at the Lawrence Berkeley National Laboratory, a U.S. government research centre in California. "Even in regions where rainfall increases, the soils will get drier. This is a very robust finding," Wehner told Tierramérica.

...The 19 models used in the study show that the increased heat will dry soils more than any additional rain can replenish soil moisture levels. Ever warmer air temperatures will cause greater evaporation, drying out soils...

The Sonoran Desert in Mexico, shot by Tomascastelazo - Tomas Castelazo, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license