By Jordan Davidson | EcoWatch
Millions of people rely on the Colorado River, but the climate crisis is causing the river to dry up, putting many at risk of “severe water shortages,” according to new research, as The Guardian reported.
Longer periods of drought and rising temperatures have decreased the river's annual flow by 20 percent compared to the last century. The researchers, who published their study in Science, say that global heating has caused mountain snowpacks that feed the river to disappear, which leads to increased evaporation, as The Washington Post reported.
“That's the thing I found most fascinating about this study,” lead author Chris Milly of the U.S. Geological Survey said to KNAU. “As the snow cover dwindles due to warming, it's reflecting less sunlight back to the atmosphere. So the basin's absorbing more sunlight. That sunlight is powering evaporation out of the basin. Now when that evaporation—the water is taken out of the basin due to the evaporation, there's less water flowing down the river to the 40 million people that are waiting for it.”
Snow and ice reflect sunlight back away from the Earth's surface, a phenomenon known as the albedo effect. The loss of snow and ice means the Earth absorbs more heat.
Milly and his research partner, Krista A. Dunne, found that for every degree Celsius of warming, the river's flow decreases 9.3 percent. Recent studies have confirmed that the river's steady decreased flow since 2000 is due to rising temperatures. The decline has amounted to 1.5 billion tons of missing water, equal to the annual water consumption of 10 million Americans, as The Washington Post reported.
