Fueled by climate change, extreme wildfires have doubled in 20 years

“This is very consistent with the effect of climate change on weather patterns around the world,” said lead author Calum Cunningham, a postdoctoral researcher at the University of Tasmania in Australia. “Climate change is making fires more extreme and more frequent in many parts of the world. »

Although previous research found a decrease in the area burned by wildfires over the century, the new study found that extreme wildfires have increased 2.2 times since 2003. Extreme wildfires have serious ecological and societal impacts, leading to deaths and loss of biomass while emitting high emissions. carbon levels. According to the study, burn severity, which is a measure of these impacts, increased in more regions than it decreased.

Cunningham said the research began in response to climate skeptics who questioned whether there was a growing fire crisis if the area burned globally was declining. Despite the increase in media coverage around wildfires, he said there is not yet scientific literature demonstrating that extreme events are changing.

“We've had this paradox where the number of fires on Earth is decreasing … and yet we have more extreme, more damaging fires,” said Stephen Pyne, a fire historian and professor emeritus at Arizona State University. “How can we reconcile these two?

Cunningham and his team analyzed data from NASA's orbiting satellites, which collected four fire measurements per day for 21 years. The results surprised him.

“I expected increases, but the pace of increases surprised and alarmed me because we are only looking over a fairly short period of time,” he said.

John Abatzoglou, a fire researcher at the University of California, Merced, said it's critical to focus on extreme fires because they tend to supplant local fire mitigation efforts.

“When we have these hot, high-energy fires, those are types of fires that are very difficult to contain and stop for fire suppression,” he said.

According to the study, as nighttime temperatures increases, the intensity of wildfires now continues to remain strong overnight. That poses a problem for firefighters who rely on that window to put out the fire, said Bobbie Scopa, a retired firefighter and author.

“This confirms what we have observed, which is that fire intensity does not decrease at night like we used to,” said Scopa, who began fighting fires in 1974.

“Twenty years ago, we rarely had 100,000-acre fires,” she added. “But now it’s not uncommon.”

Jennifer Balch, a scientist at the University of Colorado at Boulder, said firefighters today carry an excessive burden, with global warming and tens of millions of American homes facing the risk of wildfires.

Although the team is continuing research to study the scientific phenomena behind this trajectory, Cunningham said climate change has made fires hotter and drier, creating the ideal conditions for wildfires to erupt. , even in environments where fires are rare.

Extreme wildfires have increased disproportionately in certain regions: North America, Australia, Oceania and the Mediterranean. Researchers have particularly noted an increase in wildfires in coniferous and boreal forests, mainly in North America and Russia. In temperate coniferous forests, extreme wildfires have increased 11-fold, accompanied by a 7-fold increase in boreal forests.

“Climate change is not something abnormal in the future,” Cunningham said. “This is happening before our eyes. This is the manifestation of the climate overhaul we are carrying out.