Big Changes Ahead
For Climate - California
In For Major Shift
By Jane Kay
Examiner Environmental Writer

Warmer, wetter winters. Hotter, drier summers. Species disappearing and fish stocks in flux. More floods, landslides, wildfires, pests and pestilence.
Signs of the apocalypse?
Actually, those changes are likely in California's future, according to a two-year study released Thursday.
The prestigious panel of the nonprofit Union of Concerned Scientists and the Ecological Society of America concludes that shifts in temperature and rainfall over the next century will probably reduce the already scarce supply of fresh water.
"There's good evidence that the climate will change globally, and it will change in California," said Christopher B. Field, lead author and faculty member of Carnegie Institution of Washington's Department of Plant Biology on the Stanford University campus.
"The best available evidence indicates warming over the next century of 5 to 6 degrees Fahrenheit in the winter and 1 to 2 degrees in the summer," Field said. "The evidence also indicates wetter winters and probably drier summers. All the changes acting together will have a profound effect on water resources in California."
Some of the predictions of "Confronting Climate Change in California: Ecological Impacts on the Golden State," the 62-page study:
Summer water shortages could intensify competition for water among cities, farms, businesses and ecosystems that depend on rivers and runoff. Grapes, cotton, alfalfa and other crops that use lots of water may reap smaller profits. Droughts could intensify economic and environmental loss from wildfires and damage to forests from pine bark beetles.
Less fresh water entering the Bay would change water salinity, quality and circulation, disrupting the food chain. This could threaten the commercial supplies of anchovies and herring and endangered salmon and steelhead trout.
More winter rain could cause flooding " including along 1,100 miles of Delta waterways " landslides, erosion and risks of waterborne and pest-borne diseases. A one-foot rise in sea level from melting icecaps by 2100 means that reaching high-tide peak on the lower San Joaquin River would change from an event that occurs every 100 years on average to every 10 years.
El Nios, which have had a particularly dramatic effect on California's weather and economy, may increase in intensity and frequency as the climate changes. These turbulent weather patterns would amplify the impact of the rise in sea level on coastal wetlands, agriculture and housing.
Even though winters may be wetter, warmer weather means more of the precipitation would be rain that would fill rivers, the study found, instead of snow that
would build a Sierra snowpack.
"That means we'll have much more winter runoff," said Field. "By the time you get into the summer, the stream flow may be less. Warmer summers increase evaporation, which will further increase water shortage."
The Intergovernmental Panel on Climate Change, a group of more than 500 scientists, concluded in 1995 that warming would increase between 2 and 6 degrees Fahrenheit in the next 100 years, the fastest pace in human history.
Most of the climate change is driven by human activities, it said, as carbon dioxide is released by burning fossil fuels, and, to a lesser degree, its removal from the atmosphere is decreased by the cutting of forests. The gas traps solar heat within Earth's atmosphere in a greenhouse effect.
Except for a few dissenting voices, scientists agree the
sea level in California will rise by 8 to 12 inches in the next 100 years, two to three times the increase seen in the Pacific Ocean at San Francisco over the past 150 years.
California already affected
The effects of climate change already have begun in California, some studies show.
For example, a warming of the currents off California in recent decades has been linked to population declines of zooplankton, tiny creatures at the base of the food chain, and of seabirds called sooty shearwaters.
In kelp forests off the Southern California coast, the proportion of northern cold-water fish species has dropped by half since the 1970s. The proportion of southern warm-water fish species has increased nearly 50 percent.
At least one California butterfly species, Edith's checkerspot, is shifting from the southern to the northern limits of its range, a likely consequence of rising temperatures.
Only in the last decade, with more precise models, could scientists predict the regional effects of global climate change. The predictions are still sketchy, but the scientists agree that the changes are likely to vary
widely across the state.
One scenario predicts much more rain over California with dry areas to the east of the Cascades and Sierra Nevada. Winter precipitation over the coast and Sierra could rise by 25 percent or more, it showed.
Another shows the strongest warming in the northern Sierra and Central Valley, with increased drought in the southeastern corner of the state.
Major shifts in ecosystems
The state's changing climate could result in major shifts in ecosystems, the study predicts. Grassy savannahs would likely encroach on the arid foothill chaparral of the coastal ranges and the Sierra Nevada. At higher elevations, shrubs could replace forests. Off the north coast, changing current temperatures could influence the fog, which is favorable for redwood forests.
California's ecosystems are already vulnerable, sometimes whittled down to small patches harboring imperiled species.
The panel of scientists recommended limiting fossil fuel
emissions. In addition, it advised limiting development to provide more breathing room for ecosystems to deal with climate changes.
"It's not all bad news, and there are some things that can be done," said Field. "We hope the study will help to consider the environmental consequence of future change, and take steps to protect these environmental values."
The Union of Concerned Scientists is a 30-year-old nonprofit dedicated to advancing responsible science and technology public policies, and the Ecological Society of America is an association of 7,000 professional members. Both are based in Washington D.C.