- U.S. Forest Service
"The climate has become more conducive to wildfires over the past 30 years," said associate geography professor John Abatzoglou.
A megafire, according to the study, is the kind of fire that garners media attention and major resources to suppress, usually burning more than 12,000 acres. They're the top 1 percent of fires across the country in a fire season. According to Abatzoglou, both slow moving climate features like drought and more temporary conditions like heat waves, times of low humidity and wind events are responsible for the dangerous change.
After examining historical data and creating model projections, the study found a 50 percent increase in conditions conducive to wildfires moving into the mid-21st century. That doesn't mean there will be 50 percent more wildfires. It just means every opportunity for a fire to start—whether it's from a lightening strike or a rogue campfire—is another spin of the revolver in a fiery game of Russian Roulette. With climate change, it's like playing the game with more than one bullet in the revolver.
"Climate change dries things out and provides more opportunities for the bullet in the middle of the season," Abatzoglou said. "It also extends the fire season out, so there's potential for a fire to start earlier in the year or later. It's just that many extra spins of the revolver."
Abatzoglou said he was surprised that the chance of megafires increases almost everywhere in the lower 48 states, especially in the northwest, northern California, Florida and the northern Great Lakes. He said usually climate change brings with it variable changes in precipitation and temperatures, but with wildfires, "the projections are almost unanimously an increase."
The goal of the study was ultimately to identify what areas are most at risk of megafires.
"Though we can't slow down the effects of climate change, there are ways that we can mitigate against these large fires," Abatzoglou said.
The study provides land management suggestions to keep megafires at bay, such as conducting more fuel reduction programs and letting some fires burn during years with relatively benign conditions. Letting some smaller fires create a patchwork across the land will ultimately limit very large fires that can occur during extreme weather conditions. Abatzoglou said the fires simply run out of fuel.
"Now we want to know what cities across the United States are expected to see the largest smoke impacts from fires," he said. That research hasn't been fully compiled yet.