Humans responsible for Western water woes

LIVERMORE, Calif., Feb. 1 (UPI) -- California scientists said humans are to blame for diminishing water flow in the western United States.

Researchers from Lawrence Livermore National Laboratory and Scripps Institution of Oceanography said the Rocky Mountains have warmed by 2 degrees Fahrenheit and the snowpack in the Sierras has dwindled by 20 percent over the past 20 to 30 years due to human-caused climate change.

The research, published in the online edition of Science Express, looked at air temperatures, river flow and snowpack over the last 50 years, the Livermore lab said Friday in a release.

"It's pretty much the same throughout all of the western United States," said so-author Tim Barnett of Scripps. "The results are being driven by temperature change. And that temperature change is caused by us."

By 2040, most of the snowpack in the Sierras and Colorado Rockies would melt by April 1 of each year because of rising air temperatures, the report said. The earlier snow melt would lead to a shift in river flows that could lead to flooding in California's Central Valley.