HOT ENOUGH FOR YA? SCORCHING SPELL A PREVIEW OF FUTURE, STUDY FORECASTS.

Byline: Dana Bartholomew Staff Writer

Think it's hot? Get used to it. In 50 years, the 100-degree bake will become the Death Valley broil as global warming cooks California and withers its water supply, researchers said Wednesday.

Average temperatures could rise 3 to 7 degrees the next century while springtime snowpack melts into history, according to a study of global warming and the Golden State.

``We weren't going for gloom,'' said Lisa Sloan, a University of California, Santa Cruz, earth sciences professor who authored the study. ``We were going for how the climate would change with the increase of carbon dioxide in our atmosphere.''

Sloan's research group, which included the Lawrence Livermore National Laboratory, used a sophisticated computer model to study how a doubling of ``greenhouse gases'' from preindustrial levels could affect climate change.

Their prediction, if true, portends a cataclysmic upheaval that would affect California wildlife, farmers and tens of millions of new urban residents.

The study, to be published this week in the journal Geophysical Research Letters, follows on the heels of a Bush administration nod to the inevitability of human-caused climate change.

Among the report's findings:

--Average temperatures across the state will increase between 2.52 and 6.84 degrees between 2050 and 2100.

--Warming will occur greatest in the high Sierra Nevada and Cascade Mountains ranges, with temperatures rising up to 11 degrees in April and 16 degrees in May.

--Snowpack will decrease by more than 80 percent in February, drop 13 feet in March and be nearly gone by April.

--While precipitation will remain steady in the south, Northern California can expect a 23 percent increase in rain.

``With less precipitation falling as snow and more as rain, plus higher temperatures creating increased demand for water, the impacts on our water storage system will be enormous,'' Sloan said.

Other climatologists agree.

With mountain water storage diminished, they say, the state faces hard choices on how to allocate its water supply as the state adds millions to its towns and cities.

``I don't dispute the numbers,'' said Larry Riddle, a climatologist at the UC San Diego Scripps Institute of Oceanography Climate Research Division.

``I foresee that, in the not too distant future, California is going to have to make a decision: whether to shut down the cities; whether to shut down agriculture; or build more dams.''

State water experts, however, labeled the UC study pessimistic.

While snowpack levels have diminished in the past 50 years between April and July, California's variable weather patterns make such predictions difficult, said Gary Bardin, a hydrologist with the state Department of Water Resources, who hadn't seen the UC study.

``The Santa Cruz study is one of many to look at changes we could expect,'' he said. ``This sounds like a worst-case scenario.''

Los Angeles currently gets 50 percent of its water from the eastern Sierra snowpack via its Los Angeles Aqueduct and roughly 17 percent from the western Sierra water via the State Water Project.

With less snow, Los Angeles Department of Water and Power officials said, they will have to adjust the timing of Sierra water deliveries.

``It doesn't make us press the panic button, but it does change our operations,'' said Jerry Gewe, assistant general manager for water for the DWP. ``It would have a modest impact on the Los Angeles Aqueduct system.''

Instead of shuttling water to Los Angeles during the late spring melt, the city would have to transport winter rainfall for storage in the San Fernando Valley aquifer, he said.

The UC research team said its climate report for the next century was statistically significant and the most detailed to date.

Weather forecasters, meanwhile, said the San Fernando and surrounding valleys can expect 100-degree temperatures today with a gradual cooling toward Sunday.

``It's definitely hot,'' said National Weather Service specialist Stewart Seto. ``It's the same condition as the Santa Anas, except we don't have any wind.''

Temperatures reached 102 degrees in Chatsworth on Wednesday, breaking a June 5 record of 98 degrees set in 1987. Woodland Hills, at 104 degrees, tied a record set in 1957, while Lancaster at 102 tied a record set in 1981.

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Photo:

Ted Mensakian, 8, of Glendale frolics in the surf at Will Rogers State Beach while Robert Khajetorian introduces his 14-month-old daughter, Anika, to the Pacific. By the time these children are grown, scientists predict, California will be up to 7 degrees hotter.

Charlotte Schmid-Maybach/Staff Photographer