Human-Driven Warming Made 2024–25 Wildfires Far Worse — Global Report

Human-driven warming amplified wildfire intensity and scale worldwide

Earth endured one of its most extreme wildfire years on record in 2024–25, and a major international analysis — the State of Wildfires 2024–25 report — attributes that surge largely to human-caused climate change. The report finds that global warming greatly increased the likelihood and severity of extreme fire seasons, in some regions making them 25 to 35 times more likely than in a cooler climate.

How researchers reached this conclusion

The team combined satellite observations, weather reanalysis and land-surface models to trace how heat, drought and vegetation changes converged to drive record fires from the Amazon to California. Researchers ran thousands of simulations of past fire seasons both with and without human-driven climate effects and analyzed vegetation models to understand how plant growth and mortality alter fuel availability.

"Taken together, these methods reveal both how climate change has already altered major fire events and what the future may hold," said Douglas Kelley, a land-surface modeller at the U.K. Centre for Ecology & Hydrology and a co-lead on the report.

Scale and impacts

Between March 2024 and February 2025, wildfires burned roughly 1.4 million square miles (3.7 million km²) — an area larger than India. Several regions experienced extraordinary spikes in emissions and damage:

• Bolivia recorded about 771 million tonnes of CO2, its highest total this century.
• Canada emitted over 1 billion tonnes of CO2 for the second consecutive year.
• Brazil's Pantanal wetland produced roughly six times its typical CO2 emissions for the region.

Those fire emissions feed a dangerous feedback loop: increased CO2 contributes to warming, which can create conditions that favor more extreme fires.

People, health and economic costs

The human and economic toll was severe. Worldwide fatalities exceeded 200 people, including about 100 deaths in Nepal, 34 in South Africa and 30 in the Los Angeles area. Southern California fires forced roughly 150,000 evacuations and produced estimated damages of about US$140 billion. Canada’s Jasper National Park reported over US$1 billion in damages, while Brazil’s Pantanal agribusiness sector suffered losses in excess of US$200 million.

Air quality impacts were widespread: fine particulate (PM2.5) pollution from Brazilian fires reached levels up to 60 times the World Health Organization’s recommended limits, exposing hundreds of millions to hazardous smoke.

Role of satellites and future monitoring

Much of the evidence came from low-Earth-orbit satellites. Instruments aboard NASA’s Terra and Aqua satellites, together with other space-based sensors, were critical for detecting active fires, mapping burned areas and tracking smoke. Those observations validated the fire–weather models used in the analysis. The team says future reports will increasingly use next-generation hyperspectral sensors and Earth-observation satellites to monitor vegetation dryness, fuel loads and early-stage ignitions in near real time.

What comes next

Researchers emphasize that while the climate signal is now clear in extreme fire events, urgent questions remain about practical responses. The report outlines policy considerations — including climate finance and the role of nature-based solutions — but notes that in-depth analysis of local fire-management decisions (what worked, what didn’t) is a priority for future work.

"We have not yet fully explored how local fire-management choices altered outcomes in each event — what succeeded, what failed, and what lessons can be learned," Kelley said. "Advances in methods and further study will let us address that, and it’s a priority for future work."

Bottom line: The State of Wildfires 2024–25 report shows a robust climate signal behind a record fire year, stark human and economic consequences, and an urgent need for better monitoring, preparedness and local management strategies.