By Lisa M. Krieger Posted: 09/29/2014 10:51:27 AM PDT
Updated: 09/30/2014 08:41:52 AM PDT
The stubborn high-pressure systems that block California rains are linked to the abundance of human-caused greenhouse gases that heat the oceans, according to a major paper released Monday by Stanford scientists. But two other new studies disagree — saying there’s no evidence that warming ocean waters are to blame for our drought. The dispute comes at the end of the state’s official “water year,” which closes Tuesday with less than 60 percent of average precipitation. California’s major reservoirs are collectively holding just one-third of their capacity. The three teams of scientists contributing to an annual analysis of extreme weather events agree that there is a region of exceptionally high, record-breaking ocean temperatures in the North Pacific, nicknamed “The Blob.” It’s big enough to cover the United States 300 feet deep. And they agree that warm Pacific waters — which may be linked to persistent high-pressure systems — can trigger changes in how the atmosphere sweeps across our landscape. But did we inflict this devastating drought upon ourselves?
The evidence isn’t there, conclude the editors of the report — an anthology of more than 20 climate studies published in the Bulletin of the American Meteorological Society.
“The comparison of the three studies for the same extreme event, each using different methods and metrics, revealed sources of uncertainty,” it asserts.
Leading off the three California reports, the Stanford team concluded that high-pressure systems like our current “Ridiculously Resilient Ridge,” diverting storms away from California, are much more likely to form in the presence of concentrations of greenhouse gases, responsible for climate change. “We find that it is very likely that global warming has tripled the probability of this atmospheric configuration occurring,” said Stanford climate scientist Noah Diffenbaugh, associate professor of environmental earth system science, who led the research….