A new study analyzing satellite data focused on extreme wildfires, which have severe consequences for humans and the planet.
The frequency and magnitude of extreme wildfires around the globe has doubled in the past two decades due to climate change, according to a study released Monday.
The analysis, published in the journal “Nature Ecology & Evolution,” focused on massive blazes that release vast amounts of energy from the volume of organic matter burned. Researchers pointed to the historic Australia fires of 2019 and 2020 as an example of blazes that were “unprecedented in their scale and intensity.” The six most extreme fire years have occurred since 2017, the study found.
“It’s absolutely in keeping with what climate change is doing to fire weather around the world,” said lead author Calum Cunningham, a postdoctoral research fellow at the University of Tasmania in Australia. “Climate change is making fire weather more extreme and more frequent in a lot of the world.”
Though previous research found a decrease in the area burned globally by wildfires this century, the new study found that extreme wildfire events have increased 2.2-fold since 2003. Extreme wildfires have severe ecological and societal impacts, leading to deaths and biomass loss while emitting high levels of carbon. According to the study, burn severity, which is a measure of these impacts, has increased in more regions than it has decreased.
Cunningham said the research began as a response to climate skeptics who challenged whether there is a growing fire crisis if area burned globally is in decline. Despite the uptick in media coverage surrounding wildfires, he said there was not yet scientific literature to demonstrate that extreme events are changing.
“We’ve had this paradox where the amount of burning on Earth is declining … and yet we are having fires that are more extreme, more damaging,” said Stephen Pyne, fire historian and emeritus professor at Arizona State University. “How do we reconcile these two?”
Cunningham and his team analyzed data from orbiting NASA satellites, which collected four fire measurements per day over 21 years. The results astounded him.
“I was expecting to see increases, but the rate of the increases surprised and alarmed me because we’re only looking at quite a short period of time,” he said.
John Abatzoglou, a fire researcher at the University of California at Merced, said the focus on extreme fires is critical because they tend to supersede local fire mitigation efforts.
“When we have these hot, highly energetic fires, those are the sort of fires that are very difficult for fire suppression to have the ability to control and stop,” he said.
According to the study, as nighttime temperatures increase, wildfire intensity now continues to stay strong through overnight hours. This poses a problem for firefighters who rely on that window for a break in the blaze, retired firefighter and author Bobbie Scopa said.
“This kind of confirms what we’ve been observing, that the fire intensity is not dying down at night like we used to depend on,” said Scopa, who began firefighting in 1974.
“Rarely did we have 100,000-acre fires 20 years ago,” she added. “But now, it’s not uncommon.”
University of Colorado at Boulder scientist Jennifer Balch said firefighters today bear an undue burden, with a warming climate and tens of millions of U.S. homes facing wildfire risk.
Though the team will continue their research to investigate the scientific phenomena behind this trajectory, Cunningham said climate change has made fire weather hotter and drier, lending the right conditions for wildfires to erupt — even in environments where fires are infrequent.
Extreme wildfires have disproportionately increased in certain regions: North America, Australia, Oceania and the Mediterranean. Researchers especially saw wildfires increase in conifer and boreal forests, which are primarily in North America and Russia. In temperate conifer forests, extreme wildfires have increased 11-fold, accompanied by a sevenfold increase in boreal forests.
“Climate change is not something off in the future,” Cunningham said. “It’s happening before our very eyes. This is the manifestation of the reshaping of the climate we are doing.”