Extreme wildfires have doubled in 20 years, study finds
The hottest year on record, 2023, was also the most extreme in terms of forest fires, according to new research.
Both the frequency and intensity of extreme wildfires have more than doubled in the past two decades, the study found. And when the ecological, social and economic impacts of wildfires are taken into account, six of the past seven years were the most “energetically intense.”
“The fact that we found such a large increase in such a short time makes the findings even more shocking,” said Calum Cunningham, a postdoctoral researcher in pyrogeography at the University of Tasmania and lead author of the book study published Monday in the journal Nature Ecology & Evolution“We are seeing the manifestations of a warming and drying climate before our eyes in these extreme fires.”
Last week, wildfires in New Mexico killed two people and burned more than 60,000 acres; in Southern California, more than 35,000 acres burned near Los Angeles; and in TurkeyAt least 12 people have died and many more were injured in fires started by burning crop residues on Thursday, Turkish health authorities and ministers said.
Even though forest fires can be deadly and cost the United States a lot of money to $893 billion per yearWhen rebuilding costs and the economic impacts of pollution and injuries are included, most fires are “relatively harmless and in most cases ecologically beneficial,” Dr. Cunningham said.
The new study looked at the total power emitted by clusters of fire events, defined as fires that raged nearby or in the same location at multiple times in a single day. The researchers analyzed 21 years of data collected by two NASA satellites between January 2003 and November 2023 to quantify how fire activity has changed over time.
They identified 2,913 extreme events from more than 30 million fires around the world. Such extreme fire events were also defined by the enormous amount of smoke they emit, their high levels of greenhouse gas emissions, which could further accelerate global warming, and the environmental, social and economic consequences of the fire.
“This has been the holy grail for me,” said David Bowman, lead author of the study and a professor of pyrogeography and fire science at the University of Tasmania. While he’s seen fires getting worse, particularly in Australia after the 2019 bushfires killed 33 people and nearly three billion vertebrates, he said he needed the study’s data to show a trend and that something huge is happening.
“When you get these signals that are so frightening, that’s also very motivating,” Dr. Bowman said. “It’s absolutely imperative that we do something about it.”
The global increase in fire frequency and intensity was driven almost exclusively by changes in two regions. In the temperate coniferous forests of the western United States and Canada, extreme wildfires have increased more than 11-fold, from six in 2003 to 67 in 2023. In the northern regions of North America and Russia, the number of extreme fires has increased by a factor of 7.3. energetic extreme fires.
The scientists want to investigate why the fires in these biomes were so extreme, but Dr. Cunningham said their findings are consistent with the effects of climate change, which is making conditions in these forests warmer and drier and making it easier for extreme events to occur.
Wildfires of this magnitude not only threaten nearby communities, but also people living far away, as dense smoke can significantly impact air quality and travel great distances.
“The biggest smoke events come from the most intense fire events,” said Jeffrey Pierce, a professor of atmospheric sciences at Colorado State University. “If you don’t have the ability to clean the air in your home or find places that have air purification systems,” wildfire smoke can have serious health effects.
Jennifer R. Marlon, a research scientist and lecturer at the Yale School of the Environment and the Yale Program on Climate Change Communication, said the study showed that humans are changing patterns of forest and grassland burning far beyond anything we have done in the world in the past.
“Larger and more severe wildfires are one of the most obvious manifestations of a warming planet,” said Dr. Marlon in an email. “If we can help people better understand that connection, we may be able to build support to work faster to reduce the root causes of the problem: burning fossil fuels.”
