California, the most populous state in the United States, will have less water, experience a loss of cropland and see soaring wildfire rates due to climate warming, according to a newly released report.

The draft Climate Action Team Report, an update of a 2006 assessment, concludes that some climate change effects could be more serious than previously thought.

Without actions to limit greenhouse gas emissions, "severe and costly climate impacts are possible and likely across California," state environmental protection secretary Linda Adams said in the report carried by the Los Angeles Times on Thursday.

The document, which officials called the "the ultimate picture to date" of global warming's likely effect on California, consists of 37 research papers that examine an array of issues including water supply, air pollution and property losses.

By mid-century, annual precipitation in Southern California could decline by 10 percent, and by 5 percent farther north, in a band near the state's midpoint, according to the report. Little change is projected in the most northern reaches of California.

Global warming is expected to increase weather swings, from years of flooding to severe drought, the report noted.

In other areas, hydropower production is expected to decline along with the snowpack, while statewide electricity use could shoot up 55 percent by the end of the century and ozone pollution will increase, the report said.

By the final decades of the century, acreage burned across much of the state's northern forests could easily double and under some scenarios quadruple, said Anthony Westerling, an assistant professor of geography and environmental engineering at University of California in Merced.

The reason is simple: As the temperature rises, the fire season lengthens and woodlands get drier, burning more readily, he said.

Richard Howitt, an agricultural economics professor at the University of California in Davis, estimates that the Central Valley's farm acreage will shrink by roughly 1.5 million acres, or 20 percent, by 2050.

The state's Sierra Nevada snowpack, which stores water and then slowly releases it to the river systems that feed the state's major reservoirs, will shrink by at least a quarter over the next four decades, previous studies have concluded.

(Xinhua News Agency April 3, 2009)