A new study by the US Geological Survey finds the river’s flow has shrunk by about seven percent over the past 30 years. As air temperature rises due to increasing emissions of greenhouse gases, more water is sucked into the atmosphere from the snowpack and the river itself instead of flowing downstream. The amount that has evaporated is equal to approximately 24 percent of the total amount of California’s annual Colorado River allocation. “These are pretty significant amounts that are being lost as temperatures have gone up,” said lead author Gregory McCabe, a climate scientist with USGS in Denver.