An unstoppable force is making California's drought worse

World-renowned for its sunny skies, moderate temperatures, and overall beauty, California's appeal could soon be a thing of the past.

Right now the area's worst drought in the last 1,200 years is consuming the sunny state, and scientists have suspected that climate change from human emissions is the driving force behind some of these extreme conditions.

"This would be a drought no matter what," A. Park Williams, who is a Columbia research professor of biology and environment, told The New York Times. "It would be a fairly bad drought no matter what. But it's definitely made worse by global warming."

Williams is the lead author of a paper published in the journal Geophysical Review Letters this week that is the most detailed study of its kind and is the first to estimate just how much climate change is contributing to California's drought.

Moreover, Williams and his colleagues report that this drought is just one in a series of dry spells that could cripple the state over the coming decades.

The researchers estimate that between 8% and 27% of the drought is likely attributable to climate change. But Williams suspects the most likely estimate is somewhere in the middle, probably between 15% and 20%.

The researchers examined monthly weather data, including rainfall and temperatures, going back 114 years to isolate the proportion of the drought they concluded was due to climate change, as opposed to natural weather variations that have heated up the state, according to Columbia University.

"A lot of people think that the amount of rain that falls out of the sky is the only thing that matters," Williams said in the university's press statement. "But warming changes the baseline amount of water that's available to us, because it sends water back into the sky."

In fact, the researchers did not find climate change altered the amount of rainfall in California, which varies widely from year to year.

Nevertheless, when rainfall declined in California in 2012, moisture evaporated at an unusually intense rate from soil, trees, and crops, the study found.

Though heavy rainfall is expected to return to the state perhaps as soon as this winter, the researchers also estimate that the continued rise in temperatures predicted over the coming decades, and subsequent moisture losses, will bring even more aridity to California in the not-too-distant future.

The ongoing drought, now in its fourth year, will cost the California economy about $2.7 billion in 2015, according to a study released this week by economists at the University of California at Davis.