A four-year drought has ravaged the state of California, but future dry spells could be even worse. What’s more, it’s humans who are exacerbating the problem.
Scientists assert that climate change, caused by human emissions, has intensified the current drought out west, adding that global warming will almost certainly cause conditions in the future that are worse in the future.
“This would be a drought no matter what,” said A. Park Williams, a climate scientist at the Columbia University. He is the lead author of the paper published by the journal Geophysical Research Letters. “It would be a fairly bad drought no matter what. But it’s definitely made worse by global warming.”
The research, which according to Stanford University climate scientist David B. Lobell is “probably the best I’ve ever seen,” comprehensively analyzes all potential combinations of temperature, rainfall, wind, and other variables that influence the drought. As many have thought in the past, human emissions are enhancing the frequency and intensity of weather events, says the study.
Specifically, the group of scientists concluded initially that somewhere between 8 and 27 percent of the lack of soil moisture over the duration of the drought was a result of human-caused climate change. However, incorporating the speed of global warming over the last few decades, that estimate is likely closer to 20 to 25 percent.
In 120 years, California has warmed by just over 2 degrees Fahrenheit. Scientists speculate that if current ineffective efforts to control the situation continue, the state could rise another five degrees in the next century.
The paper, coincidentally enough, comes just as the National Oceanic and Atmospheric Administration reported Thursday that this past July was the hottest month on record. The first seven months of 2015 have been he hottest such period; records have been kept since 1880.