Study: Shortages likely on Colorado River by 2050

If the West continues to heat up and dry out, odds increase that the mighty Colorado River won't be able to deliver all the water that's been promised to millions who rely on it for their homes, farms and businesses, according to a new study.

Less runoff the snow and rain that fortify the 1,400-mile river caused by human-induced climate change could mean that by 2050 the Colorado won't be able to provide all of its allocated water 60 percent to 90 percent of the time, according to two climate researchers at the Scripps Institution of Oceanography at the University of California at San Diego.

The more parched the landscape, the more difficult the choices will be for those with dibs on the Colorado's water and those in charge of divvying it up, said Tim Barnett, lead author of the study.

''The dry year scenarios in the future are going to be absolutely brutal,'' he said.

Barnett and fellow Scripps scientist David Pierce made waves last year with a study saying there's a 50 percent chance that Lake Mead, the reservoir created by the Hoover Dam, could run dry by 2021.

They teamed up on the latest study to predict when the river under different climate scenarios predicting 10 percent to 30 percent reductions in runoff will be unable to fully meet all of the demands put on it.

The results were published Monday in the journal Proceedings of the National Academy of Sciences.

''Without numbers like this, it's pretty hard for resource managers to know what to do,'' Barnett said.

The Colorado is a lifeline of the southwest, flowing through seven states and into Mexico and quenching the thirsts of some 27 million people who use it to irrigate crops, water lawns, produce drinking water and operate businesses.

Drought has already stressed the river. The problem is being compounded by growing populations demanding more water and the expected effects of climate change, said Brad Udall, director of the University of Colorado's Western Water Assessment.

''We're on a collision course between supply and demand,'' Udall said.

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