A new study has revealed that the severe drought currently affecting California may be caused by natural weather patterns, rather than manmade global warming. A large “blocking ridge” hovering over the Pacific Ocean, just off the coast of California, may be to blame for the lack of rainfall that California has been receiving in recent years. The blocking ridge is a high pressure zone which has been causing storm clouds to be diverted en route to California. The ridge is about four miles high and 2,000 miles in diameter (Rogers). In most years, this high pressure zone builds up during the beginning of the year and dissipates by the winter, which is usually the season during which California receives the most rainfall. However, this ridge has been unusually persistent, leading some researchers to dub it the “Ridiculously Resilient Ridge,” or “Triple R” for short (Rogers).
The ridge works by heating the water beneath it to unusually warm levels, disrupting the natural high-speed air currents that usually carry Pacific storms to the West Coast and causes them to veer farther north (Than). This has been responsible for unusual changes in global weather patterns, such as California’s drought and the snowstorm conditions on the East Coast, as the warm air over the Pacific causes cold, wet air to circulate towards the Atlantic (RT).
According to PhD candidate Daniel Swain of Stanford University, 2013 has “been the driest year on record for California so far.” This has had major implications for California’s agriculture industry and marine wildlife. The reservoirs from which California farmers mainly draw their water have been depleted to the level “where only 10-20 major storms could restore them to where they’re supposed to be,” according to Swain. In addition, due to the influx of warm water less rich in nutrients, fish have been appearing in bizarre places (RT). The lack of nutrients has also depleted the population of crustaceans which sea otters feed on, leading to more than 1,500 starving sea lion pups (Kaplan). The critical state of the drought has led California Jerry Brown to declare a state of drought emergency and all 58 California counties to be designated “natural disaster areas” (Than). Concerns have been expressed that California has only about 12 months of water left, and the severity of the drought has also been felt through rising water bills, soon to be as high as $80-$90 per month.
No one knows why the Triple R has been so persistent, but Stanford scientists believe it may be linked to the atmospheric changes produced by global warming. As more and more greenhouse gases and carbon dioxide enter the atmosphere, an environment is created where high-pressure ridges such as the Triple R are more than three times as likely to occur. Nick Bond of the University of Washington-based Joint Institute for the Study of the Atmosphere and Ocean warns, “This is a taste of what the ocean will be like in future decades. It wasn’t caused by global warming, but it is producing conditions that we think are going to be more common with global warming.”