Wildfires larger and more destructive due to climate change

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.

Climate models show 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 without human-caused global warming. Last year's burning in the Pantanal-Chiquitano region in South America was 35 times larger, while record-breaking fires also hit the Amazon and Congo.

The second annual State of Wildfires report warns that more severe heatwaves and droughts are making extreme wildfires more frequent and intense worldwide, threatening lives through fire and polluting smoke, as well as property, economies and the environment.

The report has been co-led by the UK Centre for Ecology & Hydrology, the UK Met Office, the University of East Anglia, and the European Centre for Medium-Range Forecasts (ECMWF) in Reading, with an international list of co-authors, including wildfire experts at the University of Reading.

Fire shift

A total of 3.7 million km², an area larger than India, was burned globally in 2024-25, affecting 100 million people and US $215 billion worth of homes and infrastructure. Emissions from fires reached over eight billion tonnes of CO2.

The Los Angeles wildfires killed 30 people, forced 150,000 evacuations, destroyed at least 11,500 homes and resulted in $140 billion in damage. In the Brazilian Pantanal and neighbouring Chiquitano dry forests, fires were three times larger than usual with CO2 emissions reaching six times the average.

Fiona Spuler of the University of Reading's Department of Meteorology, a co-author of the study, created the open-source software package ibicus used to evaluate and correct biases in vegetation and climate models in order to investigate fire behaviour under future climate conditions.

Spuler said: "We are witnessing a fundamental shift in fire behaviour worldwide. Extreme fire seasons that were previously only seen once in a generation could become routine within a few decades, unless urgent action is taken to prevent future global temperature rises by curbing global greenhouse gas emissions. The combination of prolonged droughts, extreme heat and abundant fuel is perfect conditions for megafires, the consequences of which many frontline communities are already facing today.”

The report projects that extreme fire seasons in Pantanal-Chiquitano could occur every 15-20 years by century's end if emissions continue on their current path, compared to once or twice in a lifetime previously.

The report's authors have urged world leaders at COP30 to make bold commitments to cut greenhouse gas emissions rapidly this decade, while also improving land and fire management policies, such as reducing deforestation, carrying out managed burning, and improving early warning systems.