About 40 million get Colorado River water 1
About 40 million get Colorado River water 2

Ian James

The Republic | azcentral.com
 

PHOENIX – Scientists have documented how climate change is sapping the Colorado River, and new research shows the river is so sensitive to warming that it could lose about one-fourth of its flow by 2050 as temperatures continue to climb.

Scientists with the U.S. Geological Survey found that the loss of snowpack due to higher temperatures plays a major role in driving the trend of the river’s dwindling flow. They estimated that warmer temperatures were behind about half of the 16% decline in the river’s flow during the stretch of drought years from 2000-2017, a drop that has forced Western states to adopt plans to boost the Colorado’s water-starved reservoirs.

Without changes in precipitation, the researchers said, for each additional 1.8 degrees of warming, the Colorado River’s average flow is likely to drop by about 9%.

The USGS scientists considered two scenarios of climate change. In one, warmer temperatures by 2050 would reduce the amount of water flowing in the river by 14-26%. In the other scenario, warming would take away 19-31% of the river’s flow.