As the state of California faces emergency-level droughts, scientists are scrambling to figure out exactly how climate change will affect the ongoing water shortage. According to a report from the New York Times, a new study from climate scientists at Columbia University warns that global warming has intensified California’s drought by as much as 20 percent.

The study says that the drought would have occurred anyway due to natural variations in the climate. Climate change, however, is making the dry period at the end of the spectrum much more pronounced. The chances of the state weathering extreme drought conditions have almost doubled over the past 100 years, and rain has become increasingly scarce.

According to A. Park Williams, a climate scientist from the Lamont-Doherty Earth Observatory at Columbia University, “It would be a fairly bad drought no matter what. But it’s definitely been made worse by global warming.”

The National Oceanic and Atmospheric Administration also revealed in a report on Thursday that July was the hottest month on record throughout the entire world since 1880. So far, heat waves on multiple continents have taken the lives of thousands of people this summer.

The recent study on how climate change is affecting the drought is one of the most detailed explanations published yet. Researchers combined data on temperature, precipitation, wind, and humidity to analyze trends and model how rising temperatures are making the drought worse.

California governor Jerry Brown is a vocal supporter of climate action, and plans to use the new study as ammunition to go after climate deniers and people with a vested interest in polluting.

“To say you’re going to ignore that there’s a huge risk here, the way we’re filling the atmosphere with heat-trapping gases, is folly, ignorance, and totally irresponsible,” the governor said.