Soil moisture 30 cm below ground projected through 2100 for two emissions scenarios. Brown is drier and blue is wetter than the 20th c. average. RCP 4.5 assumes reduced CO2 emissions. RCP 8.5 is "business as usual."
The study, published Thursday in the journal Science Advances, is based on projections from several climate models, including one sponsored by NASA. The research found continued increases in human-produced greenhouse gas emissions drives up the risk of severe droughts in these regions.
"Natural droughts like the 1930s Dust Bowl and the current drought in the Southwest have historically lasted maybe a decade or a little less," said Ben Cook, climate scientist at NASA's Goddard Institute for Space Studies and the Lamont-Doherty Earth Observatory at Columbia University in New York City, and lead author of the study. "What these results are saying is we're going to get a drought similar to those events, but it is probably going to last at least 30 to 35 years."
According to Cook, the current likelihood of a megadrought, a drought lasting more than three decades, is 12 percent. If greenhouse gas emissions stop increasing in the mid-21st century, Cook and his colleagues project the likelihood of megadrought to reach more than 60 percent....