ASP postdoc Jian Lu contributes to research
Aridity has always been the defining feature of the American Southwest, even as large-scale hydraulic engineering has allowed cities such as Phoenix and Las Vegas to burst from the desert floor.
But according to a sobering new study, the Southwest’s aridity is about to get worse. Published in the April 9 issue of Science, “Model Projections of an Imminent Transition to a More Arid Climate in Southwestern North America” predicts that climate change will permanently alter the landscape of the Southwest so severely that conditions reminiscent of the Dust Bowl days of the 1930s could become the norm within a few decades.
“Our study suggests a perpetual arid condition over the American Southwest,” says Jian Lu, a postdoctoral researcher in ASP/CGD who is an author of the study.
Of the 19 different computer models that the research team used for the study, all but one showed a drying trend in the swath of North America between Kansas, California, and northern Mexico. The models predicted an average 15% decline in runoff for the Southwest between 2021 and 2040, compared to the average surface moisture between 1950 and 2000.
The Southwest’s future droughts are expected to be of a different nature than those that have afflicted the region in the past. Scientists attribute past droughts to variations in sea surface temperatures caused by El Niño and La Niña events in the Pacific Ocean. La Niña is especially influential as it tends to shift precipitation belts north, leaving the Southwest thirsty.
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