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Droughts in California are nothing new, expert says

Tim Hearden

Capital Press

While California is enduring one of the worst droughts in its history, drought in the Golden State isn't new, an expert says. The state has endured dry periods that lasted longer than a century, and the past 150 years have actually been wetter than normal.

DAVIS, Calif. — While California is enduring one of its worst droughts in the last 500 years, drought in the Golden State is certainly nothing new, a climate expert observes.

Such natural evidence as submerged tree stumps, sediment patterns and archaeological remains of abandoned towns suggest periods when California was much warmer and droughts lasted a century or longer, said B. Lynn Ingram of the University of California-Berkeley.

The past 150 years have been unusually wet when looking at California’s history as a whole, Ingram said during a recent workshop.

“The 20th Century was a wetter century, but this is when all our water development, population growth and agricultural industry took place,” said Ingram, an earth science and geography professor who runs Berkeley’s Laboratory for Environmental and Sedimentary Isotope Geochemistry.

“It’s possible we’re shifting into a drier regime,” she said.

The future could bring reduced snowpack, drier soils, more frequent wildfires, increased dust levels and more extreme weather, requiring adjustments on the part of water planners and users, she suggested.

Ingram has co-authored a book titled “The West Without Water: What Past Floods, Droughts and Other Climatic Clues Tell Us About Tomorrow.”

Her message is in one of more than 20 videos offered by the UC’s Division of Agriculture and Natural Resources to give farmers advice on weathering the dry conditions. Other university experts are shown giving talks on such topics as groundwater, crop stress detection, surface irrigation management, salinity control and water-use efficiency.

The UC wanted to get information out to farmers without requiring them to take mornings out of their schedule to attend workshops, spokeswoman Jeannette Warnert explained.

“Farmers this time of year are so busy, and it’s tough to take time away from their farms to sit and listen (at workshops), but there’s intense interest in anything related to the drought,” she said.

The UC’s website offers opportunities for farmers to submit questions and have experts get back to them, Warnert said.

Ingram, a more than 20-year researcher who earned a doctorate in geology at Stanford University, has been involved in the cutting-edge science of paleoclimatology — the study of changes in climate taken on the scale of thousands of years.

One of her primary field areas is the San Francisco Bay and its massive watershed, which encompasses virtually the entire Sacramento Valley and part of the San Joaquin Valley.

To conclude that California has seen lengthy droughts and warm periods that persisted throughout the Medieval era, Ingram and other scientists looked at such evidence as sedimentation on the shores of Mono Lake, which shows an extended period in which lake levels were low.

The scientists counted rings on tree stumps submerged in lakes and rivers to surmise that dry periods lasted more than a century — long enough for a tree to grow. Ingram said scientists believe a current warming trend will continue.

“As the climate warms, you’re adding more energy and water vapor in the atmosphere,” she said. “That will produce larger floods and deeper droughts.”

Online

UCANR online drought seminar series:

http://ciwr.ucanr.edu/California_Drought_Expertise/Insights__Water_and_Drought_Online_Seminar_Series/



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