Wildfires across the Americas have been supercharged by climate change
Wildfires across South America and Southern California were up to 30 times larger due to human-driven climate change, according to a major new international report.
A new scientific assessment reveals that climate change significantly intensified wildfire seasons across the Americas, with devastating consequences for people, ecosystems, and economies. The State of Wildfires 2025 report, led by experts from the UK Centre for Ecology & Hydrology (UKCEH), the UK Met Office, the National Centre for Earth Observation headquartered at the University of Leicester’s science and innovation park Space Park Leicester, the University of East Anglia (UEA), and the European Centre for Medium-Range Weather Forecasts (ECMWF), highlights the growing threat of extreme fires in a warming world.
Wildfires scorched 3.7 million km² of land globally between March 2024 and February 2025—an area larger than India. Over 100 million people were affected, with damages to homes and infrastructure estimated at $215 billion. Fires released over 8 billion tonnes of CO₂, about 10% above the long-term average, driven by intense burning in South America and Canada. January wildfires in Los Angeles were 25 times larger and twice as likely due to climate change, resulting in 30 deaths, 150,000 evacuations, and $140 billion in economic losses. Fires in the Pantanal-Chiquitano region were 35 times larger than in a pre-industrial climate, with Bolivia and several Brazilian states recording their highest CO₂ emissions this century.
The report’s authors used satellite data and advanced climate models to assess the role of global warming and land use change in driving fire activity. Dr Zhongwei Liu, National Centre for Earth Observation scientist at the University of Leicester, is a co-author of the paper. She was involved in the attribution analysis of the extremes in fire weather for four major wildfire events during 2024-25. Her findings show that climate change has increased the likelihood of extreme fire events across all focal regions studied.
Dr Douglas Kelley of UKCEH 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 would not have been on an extreme scale.”
In Los Angeles, unusually wet conditions over the past 30 months led to dense vegetation growth, which then fueled fires when hot, dry weather struck in January. Similar dynamics were observed in the Amazon and Congo, where dry forests and wetlands allowed fires to spread rapidly.
If global emissions continue unchecked, regions like the Pantanal-Chiquitano could face extreme fire seasons every 15–20 years by the end of the century—events that were once considered once-in-a-lifetime. In the Congo Basin, the frequency of extreme fires could increase five-fold, though strong climate action could limit this rise to just 11%.
The report urges world leaders gathering at COP30 to commit to rapid emissions reductions this decade.
Dr Zhongwei Liu, NCEO Scientist at the University of Leicester emphasised: “Where future increases in extreme fire risk are unavoidable, early adaptation - through ecosystem management, improved fire governance, and investment in community resilience and recovery support - will be critical to reducing the human and ecological toll of tomorrow’s extreme wildfires.”
In addition to cutting emissions, the report highlights the importance of land and fire management strategies. These include reducing deforestation, controlled burning to manage vegetation, strategic urban planning with fire breaks, wetland restoration, improved early warning and fire detection systems, and public education to prevent accidental fires.
The research team has already begun analysing wildfires from the current season, including those in Southern Europe and the UK during summer 2025. Their findings will continue to inform global efforts to understand and mitigate the growing wildfire crisis.