Guest essay by Eric Worrall

UCLA thinks that by the end of the century, Climate will reduce the Sierra Nevada snowpack by 85%.

Climate change puts California’s snowpack in jeopardy in future droughts

UCLA research shows how warming trends affect the Sierra Nevada now and in the future

Belinda Waymouth | March 09, 2017

Skiing in July? It could happen this year, but California’s days of bountiful snow are numbered.

After five years of drought and water restrictions, the state is reeling from its wettest winter in two decades. Moisture-laden storms have turned brown hillsides a lush green and state reservoirs are overflowing. There’s so much snow, Mammoth Mountain resort plans to be open for business on Fourth of July weekend.

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The Sierra Nevada snowpack, which provides 60 percent of the state’s water via a vast network of dams and reservoirs, has already been diminished by human-induced climate change and if emissions levels aren’t reduced, the snowpack could largely disappear during droughts, according to findings in the study published today in the journal Geophysical Research Letters.

“The cryosphere — frozen parts of the planet — has shown the earliest and largest signs of change,” said UCLA climate scientist Alex Hall, who along with study co-author Neil Berg modeled what future California droughts will look like in terms of snowpack loss. “The Sierra Nevada are the little piece of the cryosphere that sits right here in California.”

During a drought we see less overall precipitation. Adding in warmer air caused by climate change a greater share of precipitation falls as rain, and snow melts more rapidly. So a frozen resource that gradually melts and recharges reservoirs is particularly vulnerable to a warming climate and droughts that are expected to become increasingly severe.

To protect California’s future from the threat of warming temperatures California needs to rapidly reconfigure its water storage systems and management practices.

“I think there are serious questions about the suitability of the current water storage infrastructure as we go forward,” said Hall, a professor of atmospheric and oceanic sciences said.

Besides offering a window into the future, the UCLA study revealed some climate effects that are already happening. Hall and Berg found that the Sierra Nevada snowpack during the 2011 to 2015 drought was 25 percent below what it would have been without human-induced warming. The effect was even worse at elevations below 8,000 feet, where snow decreased by up to 43 percent.

“Seeing a reduction of a quarter of the entire snowpack right now — not 20, 30 or 40 years from now — was really surprising. It was almost as if 2015 was the new 2050 in terms of the impacts we were expecting to see,” said Berg, who is a scientist at RAND Corp.

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