​​​​​​​Climate change drove extreme wildfire seasons across the Americas, making burned areas around 30 times larger

(Press-News.org) Human-driven climate change made wildfires in parts of South America and Southern California many times larger and more destructive, according to an annual assessment by international experts.

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.

However, it is still too early to tell how much climate change contributed to the impacts of the wildfires.

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 Weather Forecasts (ECMWF). 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 Dr 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.”

Summary of extreme fire season

A total of 3.7 million km2 – an area larger than India – was burned by wildfires globally in 2024-25. 100 million people and US $215 billion worth of homes and infrastructure were exposed to wildfire (ie were in the vicinity of fires). Emissions from fires reached over eight billion tonnes of CO2 – around 10% above the average since 2003 – driven by unusually large and intense forest fires in South America and Canada. The wildfires in Los Angeles in January 2025 caused 30 deaths, forced 150,000 evacuations, destroyed at least 11,500 homes and resulted in economic losses totalling $140 billion. Canada saw its second successive year of CO2 emissions over a billion tonnes, with wildfires in Jasper National Park alone causing over US $1 billion in damages. Bolivia had its highest CO2 emissions total this century (700 million tonnes), as did four states of Brazil, three states of Venezuela, and over 20 states across Guyana, Peru, Suriname and Ecuador. In the Brazilian Pantanal, the world’s largest wetland, and the neighbouring Chiquitano dry forests of Bolivia, fires were three times larger than usual and CO2 emissions reached six times the average. Concentrations of particulate matter PM 2.5 were up to 60 times the World Health Organization air quality standards and the Pantanal’s agribusiness sector lost over $200 million. Elsewhere around the world, there were 100 deaths in Nepal, 34 in South Africa, 23 in Côte d’Ivoire, 16 in Portugal, 15 in Turkey, and two in Canada. 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 Dr 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
The report authors warn that 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. “Our climate models show the trend towards more frequent and severe wildfires will continue, especially in a world where there are high greenhouse gas emissions,” said Dr Andrew Hartley of the Met Office, a co-author of the study.

Call for action at COP30
Whatever global action is taken on climate change, there will still be more wildfires across the world in future due to the warming that has already happened. However, large-scale reductions in greenhouse gas emissions will mean the predicted increases in frequency and severity of fire will be at a much-reduced rate.

Report co-lead Dr Matt Jones of the University of East Anglia said: “We urge world leaders at COP30 to make bold commitments to cut greenhouse gas emissions rapidly this decade. This is the single most powerful contribution that most developed nations can make to avoiding the worst impacts of extreme wildfires on living and future generations.”

Land and fire management policies and practices can also help to mitigate damage. Measures to limit the risk of fires spreading include:

Reducing deforestation Managed burning in some areas to reduce the build-up of vegetation that could act as fuel for wildfires Putting buildings away from areas at high risk and having ‘fire breaks’ Protecting and restoring habitats such as wetlands Enhancing early warning systems and fire detection systems Public campaigns to reduce accidental fires.  Dr Maria Barbosa, a wildfire scientist at UKCEH and co-author of the report, added: “It is not too late to act to prevent a dramatic escalation in wildfires in regions across the world, and limit the risks to people, property, infrastructure, economies and biodiversity.”

The team of researchers has already begun investigations into wildfires in the current fire season, including in Southern Europe and the UK this summer.

– Ends –

Media enquiries

An embargoed copy of the report, the Summary for Policymakers and suggested images are available in a dropbox. For an interview with one of the report authors or further information, please contact Simon Williams, Media Relations Officer at UKCEH, via simwil@ceh.ac.uk or +44 (0)7920 295384.

Report information

The State of Wildfires report 2024-25 is published in the journal Earth System Science Data (DOI: 10.5194/essd-17-5377-2025. Open access). It has been compiled by more than 60 researchers and institutes from 20 countries. The first annual report, covering the fire season March 2023-February 2024 was published in August 2024.

As the impacts of wildfires on people and the environment are escalating, the researchers have united to help monitor, explain and predict extreme wildfires, and boost society’s resilience to the increasing risks.

There is more information about the State of Wildfires project at stateofwildfires.com

The next episode of UKCEH’s Counting the Earth podcast series, which focuses on wildfires and the report, will be available on 16 October. It includes interviews with Dr Douglas Kelley as well as Andy Elliott, Wildfire Tactical Adviser from Dorset & Wiltshire Fire and Rescue Service.

END