Due to global warming, a megadrought is likely in store for the southwestern United States in the future, researchers say.

According to a new study, the chances that this region will experience a decade-long drought is at least 50 percent, and the odds of a "megadrought" - one that lasts over 30 years - ranges from 20 to 50 percent over the next century.

"For the southwestern US, I'm not optimistic about avoiding real megadroughts," lead author Toby Ault of Cornell University said in a statement. "As we add greenhouse gases into the atmosphere - and we haven't put the brakes on stopping this - we are weighting the dice for megadrought conditions."

And according to a newly leaked UN climate report, the world isn't much closer to reaching its goal of reducing global warming to 2 degrees Fahrenheit and cutting its dependence on fossil fuels.

Droughts have left California water-deprived for almost four years now, classifying the state as D4, meaning "exceptional drought." Oregon, Arizona, New Mexico, Oklahoma and Texas are also experiencing lack of rain, and are teetering on the edge between moderate and exceptional drought - the most severe category.

Ault and fellow climatologists don't know for sure when the severe western and southwestern drought will end, if it indeed does end soon, but Ault says, "With ongoing climate change, this is a glimpse of things to come. It's a preview of our future."

Using computer modeling, researchers tried to figure out our country's future in terms of drought. They found that while California, Arizona and New Mexico will likely continue to deal with drought, the researchers show the chances for drought in parts of Washington, Montana and Idaho may luckily decrease.

Beyond the United States, southern Africa, Australia and the Amazon basin are also vulnerable to the possibility of a megadrought. With increases in temperatures, drought severity will likely worsen, "implying that our results should be viewed as conservative," the study reports.

"These results help us take the long view of future drought risk in the Southwest -- and the picture is not pretty. We hope this opens up new discussions about how to best use and conserve the precious water that we have," added researcher Julia Cole.

The findings were published in the Journal of Climate.