Study Finds Climate Shift Threatens California

A scientific study: " released on Monday presents an alarming view of climate changes in California, finding that by the end of the century rising temperatures could lead to a sevenfold increase in heat-related deaths in Los Angeles and imperil the state's wine and dairy industries.

The study, published in the online version of the Proceedings of the National Academy of Sciences, offers the most detailed projection yet of changes in California as temperatures rise around the world because of building concentrations of heat-trapping gases. Under one of two scenarios, in which fossil fuel use continues at its present pace, the study determined that summertime high temperatures could increase by 15 degrees in some inland cities, putting their climate on par with that of Death Valley now. That scenario also foresaw a reduction of 73 percent to 90 percent in the snow pack in the Sierra Nevada, resulting in disrupted water supplies from the San Francisco Bay Area to the Central Valley.

Even in the second scenario, which assumed significant increases in the use of renewable energy like wind and solar power, the study concluded that fossil fuel emissions could push average high temperatures up by four to six degrees. The study warned that the higher temperatures could have devastating consequences for wine grapes, which could ripen more quickly and be of poorer quality, and for cows, which could produce less milk. In cities like Los Angeles, it found, the number of days of extreme heat could increase by four to eight times. It projected that heat-related deaths in Los Angeles, which it said averaged 165 annually during the 1990's, could double or triple under the moderate scenario and grow as much as seven times under the harsher one.

The scientists said that California was chosen for the study because of its range of climates and the predominance of industries, like agriculture, that are dependent on climatic conditions. The state's economic heft - by some measures it is the fifth largest economy in the world - and its history of environmental activism were also considerations. "California alone can't address the emissions problem, but California is in a position of leadership," one of the study's authors, Peter C. Frumhoff of the Union of Concerned Scientists, said in a teleconference.