According to climate models, the Los Angeles wildfires in January were twice as likely and 25 times larger, in terms of burned area, in the current climate than they would have been in a world with no human-caused global warming. It also made last year’s burning in the Pantanal-Chiquitano region in South America 35 times larger, while also driving record-breaking fires in the Amazon and Congo.
The new report warns that more severe heatwaves and droughts are making extreme wildfires more frequent and intense worldwide, resulting in increasing threats to people’s lives, through fire and polluting smoke, as well as property, economies, and the environment.
The second annual State of Wildfires report has been co-led by the UK Centre for Ecology & Hydrology (UKCEH), the UK Met Office, the University of East Anglia (UEA), and the European Centre for Medium-Range Forecasts (ECMWF), with participation from Vrije Universiteit Amsterdam (VU).
The scientists used satellite observations as well as advanced modelling to identify and investigate the causes of wildfires from the last fire season (March 2024-February 2025) and the role that climate and land use change played.
UKCEH land surface modeller Douglas Kelley, who co-led this year’s report, said: “Our annual reports are building unequivocal evidence of how climate change is increasing the frequency and severity of extreme wildfires. Without human-driven warming, many of these wildfires, in Pantanal and Southern California, for example, would not have been on an extreme scale.”
Intensifying wildfires
A new analysis of satellite-derived fire intensity was introduced by VU researchers in this year's report.
“In Canada, we found that even though the burned area in 2024–25 was smaller than record year 2023, fires in several Canadian provinces burned more intensely and spread faster,” said Yuquan Qu of the Vrije Universiteit Amsterdam, a co-author of the report. “This shows that fires are becoming more dangerous and harder to control, a worrying trend as climate change continues to fuel more extreme fire behavior.”
Creating dangerous conditions
The scientists’ advanced modelling identified the respective roles of weather, vegetation density and ignition sources in determining the most extreme events.
Report co-lead Francesca Di Giuseppe of ECMWF explained: “Climate change is not only creating more dangerous fire-prone weather conditions, but it is also influencing the rates at which vegetation grows and provides fuel for the fires to spread.
“Our analyses detected the critical role of both extreme weather and fuel in the Los Angeles fires, with unusually wet weather in the preceding 30 months contributing to strong vegetation growth and laying the perfect foundations for wildfires to occur when unusually hot and dry conditions arrived in January.”
The amount and dryness of vegetation also played a critical role during the extreme wildfires in Amazonia and Congo, where abnormally dry forests and wetlands allowed fires to spread faster and further.
Future projections
In the Pantanal-Chiquitano region, extreme fire seasons like 2024-25, which once might have occurred only once or twice in a lifetime, could happen every 15-20 years by the end of the century if global greenhouse gas emissions continue on their current path. However, strong global climate action consistent with achieving net zero emissions by around 2070 would keep these events much rarer, limiting the increase in frequency to around one additional extreme season per century.
Meanwhile, there could be a five-fold increase in the extreme fires seen in the hardest-hit areas of the Congo Basin in July 2024. Strong climate action could limit the rise to 11%.
The annual reports of global wildfires provide important evidence about wildfires, their extent, causes and impacts in different parts of the world, and how this is changing over time.
Report information
The State of Wildfires report 2024-25 will be published in the journal Earth System Science Data. It has been compiled by more than 60 researchers and institutes from 20 countries. There is more information about the State of Wildfires project at stateofwildfires.com.