California lakes warming twice as fast as regional air

By Matt Weiser
mweiser@sacbee.com
Published: Sunday, Dec. 27, 2009 – 12:00 am | Page 1B
Last Modified: Sunday, Dec. 27, 2009 – 1:31 am Lake Tahoe, Clear Lake and four other large lakes in Northern California and Nevada are warming faster than the surrounding atmosphere, suggesting climate change may affect aquatic environments faster and sooner. The findings are reported in a new study led by researchers at NASA’s Jet Propulsion Laboratory in Pasadena. They used 18 years of temperature data from satellite sensors. It is believed to be the first time data have been dissected to reveal lake surface temperature over a period that long. The other lakes in the study are Lake Almanor and Mono Lake in California, and Pyramid Lake and Walker Lake in Nevada. Results show that the surface water temperature of the lakes rose two times faster, on average, than the regional air temperature. “It was a big surprise to see that,” said Philipp Schneider, the study’s lead author and a post-doctoral research scientist at the NASA lab. “If it turns out they’re actually changing faster than the air temperature, then there’s a whole new phenomenon going on here,” he said. “The lake ecosystems are going to be very much affected, especially because the trend we observed seems to be quite rapid.” The study was published in the November issue of Geophysical Research Letters, a peer-reviewed science journal. … For this study, that comparison was done at Lake Tahoe. For the rest of the lakes, results were compared with regional air temperatures across the California-Nevada study area. Tahoe’s surface waters warmed 3.7 degrees Fahrenheit from 1992 to 2008 – a mean annual increase of 0.23 degrees. During the same period, air temperature recorded at Tahoe City increased 0.10 degrees annually. …

Regional lake study points to faster warming