Researchers knew California’s drought was a record-breaker when they set out to find its exact place in history, but they were surprised by what they discovered: It has been 500 years since what is now the Golden State has been this dry.
California is in a fourth year of a severe drought, with temperatures so high and precipitation so low that rain and snow evaporate almost as soon as they hit the ground.
A research paper released Monday said an analysis of blue oak tree rings in the state’s Central Valley showed that the amount of mountain snow California relies on for moisture hasn’t been so low since the 1500s.
That was around the time when European explorers landed in what became San Diego, when Columbus set off on a final voyage to the Caribbean, when King Henry VIII was alive.
A team of researchers embarked on the study in April when state officials announced they had found “no snow whatsoever” in the Sierra Nevada for the first time in 75 years of measuring.
The research showed the level of snowpack is actually the lowest it has been in five centuries. Mountain snowpack provides 30 percent of California’s annual water supply when it melts and flows to rivers, streams, lakes and reservoirs. Across the state, the levels of water in those bodies are nearing historic lows.
“The results were astonishing,” Valerie Trouet, an associate professor at the University of Arizona who was a senior author for the study published in the journal Nature, told the Washington Post. “We knew it was an all-time low over a historical period, but to see this as a low for the last 500 years, we didn’t expect that. There’s very little doubt about it.”
California has experienced about a thousand more wildfires this fire season, compared with the previous one, including two that are raging in the northern part of the state.
A study by scientists at NASA and Columbia University said California was one of several states in the Southwest facing a mega-drought that could last as long as 30 years if greenhouse gas emissions are not dramatically curtailed by 2050.
A study by scientists at Stanford University said a future of more-frequent drought in California is a near certainty because temperatures are increasing at a time when precipitation rates are steady, allowing heat to overwhelm the moisture. And another Columbia study said California’s current drought is part of a natural pattern, but human-caused climate change has made it significantly worse.
The Columbia study analyzed month-to-month climate data between 1901 and 2014 to find fluctuations in precipitation, wind, temperature and humidity. It said average temperatures in California have increased by 2.5 degrees F over 113 years. And, starting in the 1960s, heat increased with the introduction of more greenhouse gases from automobiles and other sources.