The American Southwest and Central Plains could face super-droughts, even worse than the mega-droughts during the 12th and 13th Centuries that persisted for 20, 30, 40, 50 years at a time. Regions like California are already facing dry condition, which however, are milder than those during the 12th and 13th Centuries.
Ben Cook from Nasa’s Goddard Institute for Space Studies said that the droughts during 12th and 13th Centuries were the one that on-one in the history of the U.S. has ever experienced. In recent history people might only be aware of the droughts in 1930s or 1950s or the ongoing conditions in California and the Southwest today. These are naturally occurring droughts, lasting only for few years or may be a decade. Instead just imagine the current dry conditions in California going on for about two decades.
Cook and his team compared the earlier drought conditions based on tree ring data with climate simulations for the coming years. The scientists looked at regions like Arizona, western Arkansas, California, Colorado, South Dakota, most of Iowa, northwestern Louisiana, Kansas, southern Minnesota, western Missouri, Nebraska, Nevada, New Mexico, Oklahoma, northern Texas and Utah. They compared the reconstructions of past climate conditions with 17 climate models, together with indices used to denote the amount of moisture held in the soils.
This new study is published in the journal Science Advances, and the findings were also discussed at the American Association for the Advancement of Science’s Annual Meeting.
The scientists attribute the cause of drying to reduced precipitation and increased evaporation, which is driven by higher temperatures. Reductions in rainfall and snowfall, together with higher evaporation could lead to more dry soils.
Toby Ault, a study co-author from Cornell University, said that if climate change goes unattended, the Southwest and Central Plains are at risk of 80% of a 35-year-long drought somewhere around the end of this century.