New Tahoe analysis adds 'when' and 'how much' to climate change forecasts

The Lake Tahoe Basin could look considerably different at the end of this century due to the effects of climate change, according to a scientific report released that combines past data trends with advanced computer models.

Tahoe scientists issued the study late Monday that contains the most detailed forecast to date of plausible climate-change effects specific to Lake Tahoe, according to a spokeswoman with the University of California, Davis.

The 208-page study - entitled "The Effects of Climate Change on Lake Tahoe in the 21st Century: Meteorology, Hydrology, Loading and Lake Response" - claims the average snowpack in the Lake Tahoe Basin will decline by 40 percent to 60 percent by the year 2100, floods will increase in the middle of the century and prolonged droughts will become more common toward the end of the century, said Sylvia Wright, a spokeswoman for UC Davis.

"Public dollars are funding restoration programs in the Tahoe region, which is a special place for millions of people," said Geoff Schladow, director of the UC Davis Tahoe Environmental Research Center. "For these programs to succeed, resource managers need to know what to expect in the coming decades."

Schladow collaborated with John Reuter, associate director of TERC, and Robert Coats, a UC Davis researcher and consulting hydrologist, in authoring the study.

In compiling the study, UC Davis researchers drew on 100 years of data that demonstrate changes in temperature and precipitation that have historically occurred in the basin, Wright said.

The report combines past trends with computer models to produce detailed projections particular to Tahoe.

The scientists considered two possible future carbon emission scenarios: one which factors no changes in world-wide population growth and no alterations in national and international policies affecting global climate change, and the other, more "optimistic" scenario, which assumes slower growth and aggressive climate regulatory action, Wright said.

"While there is always some uncertainty when projecting this far into the future, the results appear reasonable," Reuter said. "They provide environmental managers and scientists with our first detailed glimpse of the potential impact of climate change on precipitation runoff, water quality and plant and animal resources in Lake Tahoe."

The report has value to water resource managers beyond the Lake Tahoe Basin, officials said, since many other lakes and reservoirs are likely to be affected by climate change.

"Our team came away convinced of the value of early collaboration between the science community and regional resource managers," Reuter said.

The $230,000 study was funded by the U.S. Forest Service and the U.S. Bureau of Land Management, through the Southern Nevada Public Lands Management Act, Wright said.