Jenna Ladd | February 24, 2017

The volume of the Colorado River has decreased by 19 percent since 2000, and recent research shows that climate change is partly to blame.

Two researchers from Colorado State University and University of Arizona compared temperature, precipitation and water volume in the Colorado River basin from 2000-2014 to historical records dating back to 1896. Since 2000, precipitation in region has decreased by 4.6 percent while temperatures have risen 1.6 degrees Fahrenheit above historical averages. Utilizing existing climate models, the scientists found that the river’s flow should have only decreased by roughly 11.6 percent since the drought began in the area in 2000. Instead, the river’s flow decreased by 19.3 percent due to the effects of global warming, they said.

Published last week in the journal Water Resources, the study read,

“Fifteen years into the 21st century, the emerging reality is that climate change is already depleting the Colorado River water supplies at the upper end of the range suggested by previously published projections. Record-setting temperatures are an important and under-appreciated component of the flow reductions now being observed.”

The Colorado River provides drinking water for 40 million people and irrigates 6,300 square miles of agricultural land. Moving forward, the study’s authors said precipitation in the river’s basin would have to increase by 14 percent by the end of the century in order to mitigate the rising temperature’s effects.

Brad Udall of Colorado State University is one of the study’s co-authors. He said, “We can’t say with any certainty that precipitation is going to increase and come to our rescue.”