A new study published in Science recently combined tree ring measurements and model output for the US West to show that the recent string of 18 years of drought were the worst experienced in the region since at least the 1500s and the second driest since the 800s. The scientists attribute about half the dryness to rising temperatures caused by greenhouse warming. As you can imagine, this has caused quite a flurry of stories on the topic. You can read the original paper abstract at https://science.sciencemag.org/content/368/6488/314 or articles on the topic at Yahoo News here, KPBS here, and KQED here.

Photo: M. Simmonson, USFS via Commons Wikimedia