A new report says global warming means major changes in the Sierra Nevada snow pack that supplies much of the water for California and northern Nevada.
The Sierra Nevada Alliance says the snow pack will shrink and melt earlier in the year, reducing runoff in the dry spring and summer. The snow line will climb 500 feet within decades as temperatures rise.
Besides a smaller, shorter-lived snow pack, scientists fear climate change could bring more extremes of flooding and drought to the 400-mile-long range.
Coupled with global warming, the environmental coalition´s report projects population increases in some Sierra counties from double to as much as five times their current level. And that means increased pollution into the state´s water supply.