Researchers... discovered that a critical surface temperature feedback is twice as strong as what had been projected by earlier studies.Bottom Line: Global warming plus LOCAL topography means less snowpack and bigger runoff. The amount of water stored in snow is absolutely massive. If California (and other places in the West) are going to maintain water supplies, many big (expensive!) dams may be necessary. (I am not very pleased with this idea.) Of course, they may not do the job -- we're talking massive!
The high-resolution climate model used by the team was better able to reproduce the complex topography of the western United States and capture details of the effect of snow cover on the climate system, as well as the historical record of runoff.
"The heat trapping from elevated greenhouse gases triggers the warming, but the additional warming caused by the loss of snow is what really creates the big changes in surface runoff... Scientists have known about this general effect for years. The big surprise here is how much the complex topography plays a role, essentially doubling the threat to water resources in the West."
18 Jul 2008
According to this story,