A report in the upcoming issue of Science warns that global warming could create a permanent drought in the southwest. The study reports that projections of anthropogenic (man-made) climate change conducted by nineteen different climate modeling groups show widespread agreement that Southwestern North America,and the subtropics in general, are heading toward a climate like that of the 1950’s droughts. From the abstract:
How anthropogenic climate change will impact hydroclimate in the arid regions of Southwestern North America has implications for the allocation of water resources and the course of regional development. Here we show that there is a broad consensus amongst climate models that this region will dry significantly in the 21st century and that the transition to a more arid climate should already be underway. If these models are correct, the levels of aridity of the recent multiyear drought, or the Dust Bowl and 1950s droughts, will, within the coming years to decades,become the new climatology of the American Southwest.
“Our study emphasizes the fact that global warming not only causes water shortage through early snow melt, which leads to significant water shortage in the summer over the Southwest, but it also aggregates the problem by reducing precipitation,” according to Mingfang Ting, Doherty Senior Research Scientist at Lamont-Doherty and one of the study’s co-authors.
Other regions to be affected by this subtropical drying include southern Europe, North Africa and the Middle East, and parts of South America.