VICE News is closely tracking global environmental change. Check out the Tipping Point blog here.

It might be hard to believe, but the parched, dusty American West could get a whole lot drier.

If humanity keeps pouring carbon dioxide and other greenhouse gases into the atmosphere at current rates, the already arid Western states are likely to face a "megadrought" lasting up to 30 years by the end of the century, researchers at Columbia University, Cornell University, and NASA found. Their study, published in the new scientific journal Science Advances, used measurements from tree rings to gauge previous droughts and computer models to project future ones.

NASA scientists used tree rings to understand past droughts and climate models incorporating soil moisture data to estimate future drought risk in the 21st century. (Video via NASA)

"These droughts really represent events that nobody in the history of the United States has ever had to deal with," NASA climate scientist Ben Cook said.

Western states are already grappling with a severe, long-term drought that has shriveled some of their major reservoirs to a fraction of their capacity. This week's study paints a picture of a future that "falls far outside the contemporary experience of natural and human systems in Western North America, conditions that may present a substantial challenge to adaptation," the authors wrote.