Many Western wildfires can be traced to carbon emissions and attributed to energy companies, new study concludes

The Mosquito fire in El Dorado County, Califonia, was the state's
largest wildfire in 2022. (Photo by Noah Berger, The Associated Press)

Fire needs heat, a fuel source, and plenty of oxygen. It's the same recipe for all fires, but climate change has made the Western U.S. hotter and drier--resulting in an over-abundance of two of those elements. "Almost 40% of forest area burned by wildfire in the western United States and southwestern Canada in the last 40 years can be attributed to carbon emissions associated with the world's 88 largest fossil-fuel producers and cement manufacturers, according to new research that seeks to hold oil-and-gas companies accountable for their role in climate change," reports Alex Wigglesworth of the Los Angeles Times. "In findings published in the journal Environmental Research Letters, the authors concluded that the emissions generated in the extraction of fossil fuels and the burning of those fuels have increased the amount of land burned by wildfire by raising global temperatures and amplifying dry conditions across the West. . . . This growing dryness, or aridification, has caused the atmosphere to become 'thirstier' for water, draining moisture from trees and brush and causing them to become more vulnerable to fire."

Study author Kristina Dahl told Wigglesworth, "We hope that people who are in communities that have been affected by wildfires will see this work and think about whether they want to hold these companies accountable." Wigglesworth explains. "To quantify the impact of the fossil fuel industry on wildfires, Dahl and her colleagues built on previous research that has shown that carbon emissions traced to the top 88 fossil fuel producers and cement manufacturers — including Exxon Mobil, BP, Chevron and Shell — have contributed significantly to the average temperature by which the Earth has warmed."

Wigglesworth reports, "The researchers found that changes in global mean temperature are positively linked with changes in the Western North American vapor-pressure deficit, a measure of how effectively the air can dry out plants and vegetation that ultimately become fuel for wildfires, Dahl said . . . . The researchers then estimated that emissions from the major carbon producers contributed to 48% of the increase in the vapor-pressure deficit observed over the last 120 years. Previous research has shown that this rise is strongly associated with increased burned forest lands in the Western U.S. and southwestern Canada."

The research is another landmark in the evolving study of climate change. "Up until relatively recently, the public posture of the climate-science community was that no individual extreme event could be attributed to global warming, said Noah Diffenbaugh, climate scientist at Stanford University, who was not involved in the study," Wigglesworth explains. "That changed in the early 2000s, and extreme-event attribution has since become a robust sub-field of climate science, he said. . . . Although the sub-field does not exist to provide data for legal actions, it in some ways arose from questions of law, he said. . . . Since then, attribution research has served as a foundation for liability lawsuits filed against fossil-fuel companies. . . . Asked to comment on the findings, a spokesman for the Western States Petroleum Association said that 'demonization' of the fossil fuel industry would not bring solutions."

Wigglesworth adds, "Last month, in what was seen as a major victory for plaintiffs, the U.S. Supreme Court declined to hear appeals from oil and gas companies that were seeking to have lawsuits over climate change filed by state and local governments moved to federal courts. The decision cleared a path for dozens of similar lawsuits to be heard in state courts, where communities that are suing are believed to have better chances of winning sizable damages." Diffenbaugh told Wigglesworth, "What this study shows is that using existing peer-reviewed methods, it is possible to rigorously trace the contributions from the source of emissions to the impacts."