The drought that is currently plaguing California is one of the nation’s most severe in over 1,200 years, researchers say. The California drought, a study published in the Geophysical Research Letters says, is only the first wake-up call and a preview of what’s about to come.
The lack of rain connected to the 2012 to 2014 isn’t the only surprising thing. In fact, it’s completely unremarkable on its own. It’s the combination of lack of rain with extreme heat that is so alarming. Specialists explain that these extreme temperatures have caused a drought exacerbation that ended up in the driest soil conditions that California has faced since the 9th century.
Daniel Griffin and Kevin Anchukaitis, the authors of the study, inspected tree-ring samples they collected from blue-oak trees in California. According to the two authors, this particular tree species is sensitive to rainfall so that wet periods caused wider rings while dry spells resulted in pinched rings. After collecting data from over 278 blue oak trees, Griffin and Anchukaitis compared their results with the North American Drought Atlas records. These records include tree ring data collected from giant sequoias and California bristlecone trees, all of which are also sensitive to rainfall.
“When we factor in temperature, this drought really stands out as an extreme and unprecedented case for the past 1,200 years.”
The two scientists didn’t stop here: they also estimated the soil’s moisture levels by using the Palmer Drought Severity Index. This index evaluates precipitation and evaporation levels and addresses soil moisture, essential to growing half the nation’s vegetables, worth approximately $10 billion).
Although there have been droughts that came with even less rainfall than the current one, the scientists came to the conclusion that, in terms of soil moisture, no drought that took place in the previous 1,200 years was worse. Anchukaitis said that both he and Griffin were surprised at their results. Neither of them had expected the situation to be so severe.
“California’s old blue oaks are as close to nature’s rain gauges as we get. They thrive in some of California’s driest environments.”
And although California has been soaking wet from rainfall this past week, more than 50 percent of the state is still in out-of-the-ordinary drought. To end it, both Northern and Central California require up to 21 inches of rain.