Colorado River water alert! The loss of the reflective snowpack drives evaporation. As well as reduces the flow of water, the study found. BY BOB BERWYN, INSIDECLIMATE NEWS, Feb 20, 2020
In 2018, snowpack in the Rocky Mountains was much lower than usual. Credit: Joshua Stevens/NASA Earth Observatory
The 40 million people who rely on Colorado River water. They need to prepare for a drier future.
Global warming is shrinking the Rocky Mountain snowpack that feeds the Colorado River. Moreover flows are declining at a rate of about 9.3 percent for every 1.8 degrees Fahrenheit increase in temperature. That’s according to a new that “identifies a growing potential for severe water shortages in this major basin.”
The decline is “mainly driven by snow loss and consequent decrease of reflection of solar radiation.” That’s what a pair of scientists with the U.S. Geological Survey wrote in a new paper. It was published in the journal Science. The study helps resolve a “longstanding disagreement in previous estimates of the river’s sensitivity to rising temperatures.”
The study links dwindling flow of water with the loss of albedo. This is a measure of the snowpack’s reflective quality. It’s like ice in the Arctic. Because white snow reflects solar radiation back to space. But as the snowpack in the Colorado River declines, the ground and, crucially, the air directly above the ground, warm up. Water from the melting snow or from rain evaporates from the soil. That’s rather than trickling into the streams that feed the Colorado River.
In conclusion, the scientists also finally found the link. All by measuring the relationship between the amount of water in the snow, to the amount of the sun’s incoming radiation. Plus how much of that was reflected back by the snowpack’s albedo. Thereby and finally showing that, as the snowpack dwindled, the Colorado River’s flow declined.