The spring is getting hotter and drier in the already hot-and-dry U.S. Southwest, and the changes are due to global warming and ozone depletion, according to new University of Arizona research.
The westerly path of storms across the western United States has shifted dramatically to the north over 20 years between the late 1970s and late 1990s, and as a result the spring rainy season has decreased by a month in Southern California, Arizona, Nevada, Utah, western Colorado and western New Mexico.
"We used to have this season from October to April where we had a chance for a storm," said lead researcher Stephanie A. McAfee, who will publish her findings in Geophysical Research Letters. "Now it's from October to March."
Climate models have predicted the region, already a desert made habitable only by the intense diversion of water from the Colorado River, will grow hotter and drier due to climate change. This study claims to be the first to link the poleward movement of westerly winds to the changes observed in the West's winter storm pattern.
The findings also support the notion that wildfire risk will increase in the region. Already, scientists have linked increased fire activity to global warming, which has reduced snowpack, increased evaporation and led to more hot, dry days when fires can start.
"We're used to thinking about climate change as happening sometime in the future to someone else, but this is right here and affects us now," said study co-author Joellen L. Russell. "The future is here."
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