As the atmosphere warms, climate scientists predict, forest fires will become more severe, sea levels may rise, and California's $45 billion wine industry could be imperiled by the end of the century.

Michael Hanemann, a professor of agricultural and resource economics who heads the Climate Change Center at Berkeley, is one of those experts trying to quantify the economic effects that climate change may impose. He has examined, for instance, what might happen if, as a result of global warming, more of Northern California's precipitation falls as rain rather than as snow. This sounds at first like a trivial change, but Hanemann notes that the deep snowpack that accumulates in the Sierra Nevada each winter supplies one-third of California's water supply. In addition, though 75 percent of the state's precipitation falls in the rainy season between December and March, 75 percent of the water supply is actually used in the summer months between April and September, when the fields of the Central Valley are irrigated to grow fruits and vegetables, and suburban lawns in Southern California need to be watered.

Some economists had argued that global warming might actually increase the fertility of the nation's fields, but Hanemann soon realized that these calculations-sensible for parts of the Midwest, perhaps-didn't take into account how crucial a stable supply of water was to creating profitable agriculture. In California, agriculture is not possible without irrigation systems, and if the snowpack starts melting in January, and disappears by April, this would create chaos in the state's highly designed system of dams, irrigation channels, and canals built, like the Central Valley Water Project, to funnel water 400 miles from the rainy North to the drier South. The system itself could stop functioning, Hanemann says, not because there would be a fall-off in precipitation, but because the state would have no capacity to store the excess water from winter rains until they are actually needed in August and September. He calculates the state would need to spend an additional $11 billion just to build extra storage capacity.

Hanemann also believes that rising sea levels from global warming also would prove costly to California because so many people live near the ocean or use the state's beaches for recreation. He estimates that rising sea levels would force the state to build an estimated $3.8 billion of coastal protection in Southern California alone.

Berkeley researchers aren't simply measuring the effects of climate change; they also hope to help reverse the trends. Dr. Fung is among a group of the nation's leading climatologists who have signed an amicus brief to the U.S. Supreme Court in support of the 11 states, including California, Connecticut, Illinois, and Massachusetts, that have sued the Environmental Protection Agency for failing to regulate greenhouse gases, primarily the high levels of carbon dioxide in the atmosphere. They argue that the agency is mandated to protect citizens against harmful pollutants. The EPA has questioned the severity of the global warming problem, arguing it didn't have authority to regulate carbon dioxide because it is not a pollutant, and said that the Bush administration already was taking steps to deal with climate change. In late June, the U.S. Supreme Court agreed to hear the case this fall.

Because their evidence points to the growing threat that carbon emissions are causing to the climate, Berkeley researchers also are helping California lead the way in terms of "decarbonizing" the state's economy, reducing the amount of greenhouse gases being put into the atmosphere, and increasing the efficiency of its electrical industry. Already, the state has told Detroit's automakers to reduce greenhouse gases their cars emit by 30 percent by model year 2009, in hopes that by setting a standard in the nation's most populous and car-addicted state, some form of nationwide momentum will be generated. Another legislative initiative would cut the state's greenhouse gases by 25 percent by the year 2020.

	page 4	|	5