In the southwest….

“The last 19 years have been equivalent to the worst 19 years of the worst mega-droughts on record,” said Park Williams, a professor of bioclimatology at Columbia University, at a presentation of the work. Only three recent mega-droughts—in the late 800s, the mid-1100s, and the late 1500s—were worse than the current period, he added.

Climate change seems to be driving a good chunk of the problem. “The current drought is substantially worse than it would have been without global warming,” Williams said. The drought was 62 percent more severe than it would have been, he said, due to human-caused climate change.

Robinson Meyer on new work by Lamont-Doherty’s Park Williams