California Drought Linked to Climate Change

Washington DC - infoZine - Climate scientist Noah Diffenbaugh of Stanford University and colleagues used a novel combination of computer simulations and statistical techniques to show that a persistent region of high atmospheric pressure over the Pacific Ocean--one that diverted storms away from California--was much more likely to form in the presence of modern greenhouse gas concentrations.

The result, published today in 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 emission of greenhouse gases that began during the Industrial Revolution in the 1800s," says Diffenbaugh.

The exceptional drought crippling California is by some measures the worst in state history.

The water shortage could 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 effects have prompted a drought emergency in the state; the federal government has designated all 58 California counties as natural disaster areas.

"In the face of severe drought, decision-makers are facing tough choices about the allocation of water resources for urban, agricultural and other crucial needs," says Anjuli Bamzai, program director in the National Science Foundation's (NSF) Division of Atmospheric and Geospace Sciences, which funded the research.

"This study places the current drought in historical perspective and provides valuable scientific information for dealing with this grave situation. "

Scientists agree that the immediate cause of the drought is a particularly tenacious "blocking ridge" over the northeastern Pacific--popularly known as the Ridiculously Resilient Ridge, or "Triple R"--that prevented winter storms from reaching California during the 2013 and 2014 rainy seasons.

Blocking ridges are regions of high atmospheric pressure that disrupt typical wind patterns in the atmosphere.

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California Drought Linked to Climate Change