Climate change has inexorably stacked the deck in favor of bigger and more intense fires across the American West over the past few decades, science has incontrovertibly shown. Increasing heat, changing rain and snow patterns, shifts in plant communities, and other climate-related changes have vastly increased the likelihood that fires will start more often and burn more intensely and widely than they have in the past.
The scale and intensity of the wildfires burning across the western U.S. right now is “staggering,” says Philip Higuera, a wildfire scientist and paleoecologist at the University of Montana. More than five million acres have already burned this year—and much more may be yet to come.
Noah Diffenbaugh, a climate scientist at Stanford University, makes a baseball analogy to describe increase in risk. “If there’s a three-run home run in baseball, it’s the home run that definitely caused the runners to round the bases and score. The home run is the proximal cause of the event. But people being on base matters," he says, and global warming is putting people on base.
Other factors also hike fire risk, like forest management decisions that have allowed for the buildup of vast amounts of vegetation that can quickly turn into fuel, as well as more problematic issues like the slow creep of houses and other infrastructure into risky areas. But for fires near that so-called wildland-urban interface, as well as more remote, forest-centered burns, climate change has significantly heightened the baseline risks.