Climate change plays a big role in California's epic drought

New study gives California crisis managers something else to worry about: evapotranspiration.

By Katherine Bagley, InsideClimate News
Aug 20, 2015

As California’s four-year drought has drinking and groundwater reserves at dangerously low levels, households rationing water and the agricultural sector struggling to keep its crops alive, the question has been: how much of a culprit is climate change? New research published Thursday now says as much as 27 percent of the drought can be attributed to global warming.

That new research published in the peer-reviewed journal Geophysical Research Letters, by scientists at Columbia University and the University of Idaho, examines how quickly warming temperatures from the buildup of greenhouse gases in the atmosphere is sucking California's soils and plants dry, a process known as evapotranspiration, and how drastically that process is increasing the severity of the current drought, said the study’s lead author, Park Williams, a Columbia bioclimatologist.

"Climate change is like a bully," Williams said. "Warmer temperatures steal moisture from California's water budget like a bully would from a bank account. Every year, as temperatures continue to rise, they take more and more moisture away. In the beginning it isn't really detectable, but after 120 years of warming, it is." And with no rainfall to replace the moisture during periods of drought, he explained, this lack of soil moisture worsens dry conditions.

The drought currently desiccating California has cost the state's economy an estimated $2.7 billion in 2015. The Central Valley is literally sinking 2 inches per month as dwindling groundwater supplies are sucked up to feed agricultural irrigation systems. Giant sequoia forests are showing early signs of dying of thirst. Wildfires are sweeping through dry California woods.

(Continued here.)