As Deadly Wildfires Rage in California, a Look at How Global Warming Fuels Decades of Forest Fires

In California, powerful winds and bone-dry conditions are fueling massive wildfires. A state of emergency has been declared in northern areas as the fires have left at least 17 people dead, destroying whole neighborhoods and forcing 20,000 people to evacuate their homes. The wildfires come after the U.S. Forest Service warned last year that an unprecedented 5-year drought led to the deaths of more than 100 million trees in California, setting the stage for massive fires. Climate scientists believe human-caused global warming played a major role in the drought. We speak with Park Williams, bioclimatologist at Columbia University's Lamont-Doherty Earth Observatory and co-author of a 2016 report showing that global warming is responsible for nearly half of the forest area burned in the western United States over the past three decades.