Scientists have tentatively drawn a link between human-induced climate change and California’s ongoing record drought. The atmospheric patterns behind the severe drought in California are “very likely” due to human-induced climate change, and are more likely to occur in the future with increased greenhouse gases, according to a study by scientists at Stanford University. The report, published in the Bulletin of the American Meteorological Society (BAMS), is one of the most extensive studies to date exploring this link.
California just ended its 2014 “water year”—the season-to-season accounting of the state’s rainfall—with less than 60% of average precipitation, making it one of the driest years on record. This persistent, extreme drought has been caused by high-pressure ridge over the Northeastern Pacific, known as the “ridiculously resilient ridge,” that essentially blocked winter precipitation from making it to land in Northern California. According to the study, this type of formation is far more likely in the presence of increased greenhouse gases.
Drawing direct connections between changes in greenhouse gases and a specific weather event is difficult and the scientists were unable to unambiguously blame the current drought on the increase of greenhouse gases. However, the conclusion of this research is that the conditions that cause such extreme droughts in California will be more likely in the presence of global warming.
The Stanford research is one of three California-specific studies that make up part of a larger, global assessment of extreme weather events published by the American Meteorological Society.