New York City and Los Angeles — America’s two biggest cities — have both burned in the past four months.
Though the Pacific Palisades and Altadena fires were far more destructive, turning nearly 40,000 acres of homes, schools, parks, and businesses to ash, the New York fire was in many ways just as startling. A record dry fall in the Northeast led to 600 blazes across the East Coast in October and November, including one in Prospect Park in the heart of Brooklyn, the city’s most populous borough. The FDNY later reported that it fought more than 370 brush fires in the five boroughs in 2024 — a rate of more than one a day in a place not traditionally associated with wildfires.
According to new research by Long Shi and his colleagues at the University of Science and Technology of China, published today in Nature Cities, these kinds of urban fires are becoming increasingly common due to climate change. “The impacts of climate change on vegetation fire have been well explored” by other researchers, Shi told me via email. Until now, however, the impact of anthropogenic warming on urban fires was “still unknown.”
Shi and his colleagues created a global fire incident database covering 2,847 cities across 20 countries. They found that for every 1 degree Celsius increase in air temperature (that’s just shy of 2 degrees Fahrenheit), the frequency of vehicle and outdoor fires increased by about 2.5% and 4.7%, respectively. That means that under a scenario with no new climate mitigation policies, under which greenhouse gas emissions roughly double from current levels by 2100, vehicle fires would increase by 11.6% and outdoor fires by as much as 22.2% by the end of the century.
Fire incidents typically fall into one of four categories: building, vehicle, and outdoor fires, which are usually urban, and vegetation fires, which include forest and grassland fires. Historically, fire research has tended to focus on vegetation fires, but the vast majority of the 50,000 fire-related deaths and 170,000 fire-related injuries sustained each year around the world are in urban fires. Part of that is because urban fires are much more difficult to study. “Some fire ignitions, such as inside buildings, cannot be directly detected by satellites,” Shi and his colleagues write in their report. There was also no preexisting global fire incident databases for Shi’s team to rely on, so they spent years just assembling the fire incident data before they could begin their analysis.
The final 2,847 cities considered for the report account for 20.6% of the global population — “the most comprehensive and biggest city-based fire incident database so far,” Shi said. The researchers then looked at the changes in the frequency of urban fire incidents between 2011 and 2020, focusing on building, vehicle, and outdoor fires, including garbage and landfill fires.
Perhaps surprisingly, Shi’s team found that building fires could decrease by 4.6% under a high greenhouse gas emission scenario. Their research showed that building fire frequency drops when the outdoor air temperature is “comfortable,” from 20 to 26 degrees Celsius (68 degrees Fahrenheit to about 79 degrees Fahrenheit). “This may be because people tend to stay indoors during uncomfortable weather, elevating the likelihood of accessing fire sources or devices that provide ignition sources for fires, such as fireplace heating and electrical cooling appliances,” the authors wrote. (Canada, Estonia, and Finland showed an opposite trend, which the authors hypothesized was because “people in northern countries spend more time outside in winter as they enjoy winter sports” — or just because of the relatively short period of available fire data.)
The increase in vehicle fires is a more interesting case, as the authors note. “Although we cannot separate human factors from vehicle fires, their tendencies differ from those of building fires,” they write, noting that approximately 81% of vehicle fires ensue “without human intervention.” Around two-thirds of those “befall as a result of equipment or heat source failure,” while collisions are responsible for just 5%. The rise reflected in the research may be due to “the increased failure rates of … vehicle components under rising air temperature,” though the authors also note that this finding could change as more people adopt electric vehicles, which catch fire at a lower rate than their gasoline-powered counterparts.
Though Shi is still seeking fire incident data from the countries not included in this study, the research published in Nature could have significant implications for urban planners today, Sara McTarnaghan, a principal research associate at the Urban Institute who was not involved in the study, told me.
“A lot of our capacity and infrastructure for planning around climate change in the United States really started out focused on sea-level rise and other flood-related risks,” McTarnaghan said. But fires are “a huge piece of that equation, and there’s certainly linkages with climate change that need to be better understood.”
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