Southwest Drought Linked to Climate Change

The decreasing rainfall in the southwest is caused by human-driven climate change, according to a new report.

The Colorado River Basin, and much of the southwestern US, is experiencing a historic drought-it started in 1999-so severe it’s called a megadrought.This drought in the basin, which provides water to seven states and Mexico, is a result of warming temperatures and less precipitation, especially winter snow.

Scientists have already linked warming temperatures to human activities that cause climate change. Now, Jonathan Overpeck of the University of Michigan and Brad Udall of the Colorado Water Center at Colorado State University believe that climate change is also responsible for the reduced rainfall.

“The drought has lasted over 25 years, and precipitation has steadily decreased. But recently, we thought this might just be natural variation-we expected rainfall to increase again,” says Overpeck, the dean of the UM School for Environment and Sustainability.

“Recent research shows this isn’t true. In the long term, we’ll likely have more dry winters than wet winters, and that’s as of climate change.”