"Lake Tahoe is getting warmer and the likely cause is global warming, making it the largest lake in North America where rising temperatures have been linked to climate change, according to a study by UC Davis researchers. Although the water temperature has increased by less than 1 degree Fahrenheit in three decades, scientists said, it was enough to significantly affect lake currents and to complicate the billion-dollar effort to preserve the clarity of the lake's cobalt-blue waters.
The findings suggest that by altering the currents, the warming trend may promote algae formation near Tahoe's surface and help make those waters more opaque — a condition long blamed on a combination of air and water pollution from runoff, chimney smoke and auto emissions.
Analyzing 33 years of monitoring data, a team of UC Davis scientists found that the warming trend was evident in surface-level water as well as more than 400 meters beneath the surface. They determined that the change probably is stemming from a slight uptick in temperatures around the world, ruling out other factors such as increased geothermal heat from the earth beneath the lakebed.
"Tahoe is so large, it takes a lot to change it," said Geoffrey Schladow, the director of the UC Davis Tahoe Environmental Research Center and one of the authors of the study, which has been submitted for publication in the scientific journal Climatic Change. "The temperature at the bottom has changed by nearly 1 degree Fahrenheit, and that is greater than at any other time in recorded history."
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http://www.latimes.com/news/local/la-me-tahoe21dec21,1,4563309.story?coll=la-headlines-california