Clear Lake, a haven for bass anglers and jetskiers at the foot of a dormant volcano in Lake County, is also a sentinel for climate change in California.
Satellite measurements of the shallow, 68-square-mile lake's surface water temperature show a pronounced warming since 1992, matching the trend at five other lakes in California and Nevada, including Lake Tahoe.
The lakes' warming is "primarily due to climate change," said Geoffrey Schladow, director of the Tahoe Environmental Research Center. "No other factor could produce this degree of warming in all six lakes."
Furthermore, the warming "will impact the biology" of Clear Lake, said Schladow, a UC Davis professor of water resources and environmental engineering.
"The lake is going to be different," he said.
Warming of the six lakes was included in a report by the California Environmental Protection Agency documenting 36 indicators of climate change from the coast to the Central Valley and the Sierra Nevada.
The indicators include rising sea levels, shrinking glaciers, decreasing snowmelt runoff, increasing wildfires and gradual migration of plants and animals to higher elevations, according to the 258-page report.
"Together, these indicators paint a disturbing picture of how climate change is affecting our state and its growing threats to our future," said Dr. George Alexeeff, director of the state Office of Environmental Health Hazard Assessment.
Lakes "serve as good sentinels for climate change," the report said, noting that freshwater is "one of the resources most jeopardized by a changing climate."
Warmer waters at Lake Tahoe, undoubtedly California's favorite lake, may be making the cold, alpine lake more hospitable to algae, the report said.