Water source for 40 million Americans could be drying up. Here’s why

A source of water for 40 million people in the U.S. could dry up because of climate change, scientists say.

The Colorado River provides water to about 40 million people from Denver to Phoenix and Las Vegas, Science News reported, and it irrigates farmlands across the southwest. The river also supports $1 trillion in economic activity each year, according to The Washington Post.

Scientists from the U.S. Geological Survey in Princeton, New Jersey, found that climate change is threatening the river, which could have “catastrophic consequences,” Newsweek reported.

“In the Colorado River Basin, when you touch water, you touch everything — our economy, our culture, our environment,” Brad Udall, a senior water and climate research scientist at Colorado State University who has studied the river, said in Newsweek. “Flow losses will impact U.S. agriculture, all aspects of our economy including world-class Rocky Mountain tourism and our way of life.”

The river’s annual flow has decreased by nearly 20 percent over the past century, according to The Washington Post.

Scientists say it’s because climate change is making mountain snowpacks disappear, which increases evaporation, The Washington Post reported.

“The Colorado River Basin loses progressively more water to evaporation, as its sunlight-reflecting snow mantle disappears,” USGS scientists Chris Milly and Krista A. Dunne wrote.

Milly and Dunne used simulations and climate models to predict temperature increases in hypothetical emissions scenarios, Science News reported. If nothing is done to curb fossil fuel emissions, the river flow could drop 19 to 31 percent by mid-century.

“And this number is worrying,” Udall told The Washington Post. “I would say eye-popping.”

This story was originally published February 21, 2020 at 12:55 PM with the headline "Water source for 40 million Americans could be drying up. Here’s why."