Ru-oh. The water wars are getting closer. Better make those visits to Southern California sooner than later.
As signals of climate change begin to come into focus in the Sierra Nevada, its melting glaciers spell trouble in bold font. Not only are they in-your-face barometers of global warming, they also reflect what scientists are beginning to uncover: that the Sierra snowpack – the source of 65 percent of California’s water – is dwindling, too.
More of the Sierra’s precipitation is falling as rain instead of snow, studies show, and the snow that blankets the range in winter is running off earlier in the spring. And snow in the Sierra touches everything. Take it away and droughts deepen, ski areas go bust and fire seasons rage longer.
Some glaciers already have melted away, including the first Sierra glacier discovered in Yosemite by John Muir in 1871. Today, the remaining 100 or so are withering, including Lyell, the second-largest, which could be gone inside a century.
“All across the Sierra, glaciers are transitioning into ice patches. Ice patches are transitioning to snow fields. And snow fields are transitioning into bedrock,” said Greg Stock, a geologist with Yosemite National Park who joined Devine last month on an annual survey of the Lyell glacier.
While this is not the first time glaciers have receded across the Sierra Nevada – they last did so about 20,000 years ago – this meltdown is more ominous, Stock said, because scientists increasingly believe it is sparked not by natural forces but by rising carbon dioxide levels from the burning of fossil fuels.
“We have entered new terrain with what’s going on in the atmosphere,” he said. “We haven’t seen anything like this in tens of millions of years.”