TIME climate change

Southwestern U.S. Faces ‘Mega-Drought’ by End of Century

mega-drought california drought
Kristian Bell—Getty Images/RooM RF

A mega-drought would make the ongoing California drought look small

The U.S. Southwest could face destructive mega-droughts unless dramatic action is taken to curb emissions of the greenhouse gases that cause climate change, according to new research.

Researchers behind the study, published in the journal Science Advances, found that expected temperature increases will lead to a 70% chance of a mega-drought assuming a moderate increase in precipitation. If rainfall remains constant or falls, the chance of a mega-drought soars above 90%, according to the study.

Mega-droughts have the intensity of the worst droughts of the 20th century but last for decades. A mega-drought in the American Southwest would strain water resources in a highly populated region. The ongoing California drought has led to unprecedented water restrictions after only six years.

Researchers say their findings have a silver lining: ongoing efforts to reduce greenhouse gas emissions could significantly limit the chances of such a drought. If temperature rise in the region remains below 2°C (3.6°F), the risk of a mega-drought will drop below 66% in most cases of precipitation, according to the study. The stated goal of the Paris Agreement on climate change is to keep global temperature rise below 2°C (3.6°F) by 2100.

Tap to read full story

Your browser is out of date. Please update your browser at http://update.microsoft.com


Dear TIME Reader,

As a regular visitor to TIME.com, we are sure you enjoy all the great journalism created by our editors and reporters. Great journalism has great value, and it costs money to make it. One of the main ways we cover our costs is through advertising.

The use of software that blocks ads limits our ability to provide you with the journalism you enjoy. Consider turning your Ad Blocker off so that we can continue to provide the world class journalism you have become accustomed to.

The TIME Team