Southwestern states in the U.S. are at risk of severe long-term droughts driven by climate change.

According to a recent study published in Science Advances, there is a 99 percent chance that a "megadrought" lasting for decades could hit the southwest this century.

Researchers from Cornell University, the Lamont-Doherty Earth Observatory of Columbia University and the NASA Goddard Institute of Space Studies said that rising temperatures combined with decreased rainfall in the region will create droughts that could be worse than the American Dust Bowl--a decade-long drought and decline in agricultural production that happened during the 1930s and affected 100 million acres of land in Texas and Oklahoma, as well as adjacent states Kansas, Colorado and New Mexico. During this time, dust storms also swept the farmlands and spread dust to eastern states Chicago, New York and Washington.

According to the study, staying within the 2-degrees Celsius level of global warming--the upper-limit goal of the Paris agreement--could bring about a 30 to 60 percent chance of megadrought. At the level of 4 degrees Celsius, which is the rate the planet is currently going, megadroughts are certain to occur.

"Historically, megadroughts were extremely rare phenomena occurring only once or twice per millennium," the report said. "A megadrought occurring again in the Southwest in the coming decades would impose unprecedented stresses on water resources of the region, and recent studies have shown that they are far more likely to occur this century because of climate change compared to past centuries."

California alone is currently plagued by severe drought conditions. About 62 percent of the state is affected and it is already entering its sixth consecutive year of drought, with the lowest record of rain so far, EcoWatch reports. Under the 4-degree scenario of the study, California is 90 to 100 percent at risk of megadrought.

The researchers call for reduced demand, water efficiency, shifts to groundwater, and a further decrease in greenhouse gas emissions to solve the looming crisis.