EurekAlert!: The atmospheric conditions associated with the unprecedented drought currently afflicting California are “very likely” linked to human-caused climate change, Stanford scientists say.

In a new study, a team led by Stanford climate scientist Noah Diffenbaugh used a novel combination of computer simulations and statistical techniques to show that a persistent region of high atmospheric pressure hovering over the Pacific Ocean that diverted storms away from California was much more likely to form in the presence of modern greenhouse gas concentrations.

The research, published on Sept. 29 as a supplement to this month’s issue of the Bulletin of the American Meteorological Society, is one of the most comprehensive studies to investigate the link between climate change and California’s ongoing drought.

“Our research finds that extreme atmospheric high pressure in this region—which is strongly linked to unusually low precipitation in California—is much more likely to occur today than prior to the human emission of greenhouse gases that began during the Industrial Revolution in the 1800s,” said Diffenbaugh, associate professor of Environmental Earth System Science at Stanford and a senior fellow at the Stanford Woods Institute for the Environment.

The exceptional drought currently crippling California is by some metrics the worst in state history. Combined with unusually warm temperatures and stagnant air conditions, the lack of precipitation has triggered a dangerous increase in wildfires and incidents of air pollution across the state. A recent report estimated that the water shortage would result in direct and indirect agricultural losses of at least $2.2 billion, and lead to the loss of more than 17,000 seasonal and part-time jobs in 2014 alone. Such impacts prompted California Governor Jerry Brown to declare a drought emergency, and the federal government to designate all 58 California counties as “natural disaster areas.” [Continue reading…]