Extreme weather seems to make the headlines almost every week, as disasters increasingly strike out of season, break records, and hit places they never have before.
Decades of scientific research has proven that human-caused climate change is making some disasters more dangerous and more frequent. The burning of fossil fuels like oil, gas, and coal releases carbon dioxide into the Earth’s atmosphere, where it traps heat, warms the planet, and alters the conditions in which extreme weather forms. These changes are happening more rapidly than at any time in the last 800,000 years, according to climate records.
Below, we break down what experts know — and what they don’t — about the connections between climate change and wildfires.
In a hotter, drier world, wildfires have become more frequent and destructive. Scientists have definitively linked anthropogenic climate change to increased wildfire risks: A 2016 study found that, because of human-caused carbon emissions, the total number of large fires since 1984 had doubled. A 2021 study supported by NOAA similarly concluded that climate change is primarily responsible for wildfire conditions, like hotter and drier summers. Wildfires themselves also release carbon when trees and other vegetation go up in flames. Globally, in 2023, wildfires caused 8.6 billion metric tons of carbon dioxide emissions.
The Western United States is the epicenter of the country’s growing wildfire crisis: Dry, hot conditions are getting more dangerous, snow is melting earlier in the spring, and summer droughts have become more severe. Warming temperatures also encourage outbreaks of pests like bark beetles, weakening or killing wide swaths of forests. This dead and dried out vegetation becomes kindling waiting for a spark — whether that’s trash or debris fires, lightning strikes, or ill-advised fireworks.
But these risky conditions are now more common in other parts of the country as well. On the East Coast, states are experiencing more “fire weather” days per year than they were 50 years ago. In New Jersey’s Pine Barren forest, for example, dry fall and winter conditions mean that deciduous trees shed drier leaves onto the forest floor — essentially, kindling waiting for a spark.
As the conditions that fuel wildfires have worsened, so too has the number of people living in wildfire-prone zones. Between 1990 and 2010, according to the Forest Service, housing developments in the “wildland-urban interface” — a vulnerable ecological area where housing abuts or intermingles with the edges of forest — increased by 41 percent.
Like most climate events, wildfires are an inherent natural process, and plant species have adapted to live alongside lower-intensity, cyclical fires. For thousands of years, Indigenous tribes reduced fire risks by using controlled or cultural burns, strategically clearing areas of dried-up vegetation before nature takes its course. European settlers, and later the federal government, did not have the same relationship to fires and forests. The cultural and ecological practice was banned for centuries in some states, including California. The U.S. Forest Service also had a “10 a.m. policy” for decades that instructed fire agencies to extinguish every blaze the same day it started — even those burning low and slow. Abandoning controlled burns and focusing on fire suppression caused a buildup of dead vegetation that helped fuel larger fires. Only recently have some ecologists and lawmakers reversed course, collaborating with tribes to reintroduce controlled burns to improve forest management.
“There are solutions we have in our knowledge and in our management approaches that can help restore these ecosystems and can also benefit the public,” U.S. Forest Service research ecologist Frank K. Lake, a descendant of the Karuk tribe, told Grist in 2020.