Mike McMillan/ USFS, Public domain, via Wikimedia Commons.
Record-breaking 2024 Amazon fires caused unprecedented carbon emissions and ecosystem degradation.
A new study by researchers at the European Commission’s Joint Research Centre has revealed that the Amazon rainforest has just undergone its most devastating forest fire season in over two decades, which triggered record-breaking carbon emissions and exposed the region’s growing ecological fragility despite a slowing trend in deforestation.
The 2024 fires released an estimated 791 million tons of carbon dioxide into the atmosphere, which roughly equates to the annual emissions of Germany.
This marks a sevenfold increase from the average of the previous two years.
According to the study, 3.3 million hectares of Amazon forest were impacted by fires last year alone.
This extraordinary surge in fire activity is likely driven by a combination of extreme drought stress exacerbated by climate change, forest fragmentation, and land-use mismanagement (eg, escape fires or criminal fires by land grabbers), leading to significant forest degradation.
For the first time in the analysis covering 2022–2024, fire-induced degradation has overtaken deforestation as the primary driver of carbon emissions in the Amazon.
Pan-Amazon map showing newly detected large-scale forest degradation in 2024, primarily driven by fires, along with country-level trends in deforestation, forest degradation, and forest fires from 2022 to 2024 (source: Bourgoin et al., 2025). Credit: Bourgoin et al.
New level of precision
This research draws on a sophisticated satellite-based methodology that overcomes many of the limitations of previous global fire datasets.
By combining data from the Tropical Moist Forest monitoring system with the Global Wildfire Information System and filtering out false signals caused by agricultural fires or cloud cover, scientists were able to detect and verify fire-driven forest degradation with a novel level of precision.
The geographical spread of the fires was equally alarming.
In Brazil, 2024 marked the highest level of emissions from forest degradation on record. In Bolivia, fires affected over 9% of the country’s remaining intact forest cover, which is a dramatic blow to a region that has historically served as a vital biodiversity reservoir and carbon sink.
To ensure scientific rigor and transparency, the researchers used a Monte Carlo simulation framework to estimate carbon emissions and their uncertainties across variables such as above-ground biomass density, combustion completeness, and the percentage of forest cover affected by fire.
The resulting confidence intervals adhere to Intergovernmental Panel on Climate Change (IPCC) best practices and offer a robust benchmark for tracking the carbon consequences of forest fires in tropical regions.
Insidious threat
While past reports have highlighted the dangers of deforestation, this study spotlights a more insidious threat: fire-driven degradation that erodes forest integrity without necessarily clearing it.
Degraded forests may look intact from above, but they lose a significant portion of their biomass and ecological function.
Unlike clear-cut areas, these degraded forests often fall through the cracks of national accounting systems and international policy frameworks.
The study calls for immediate and coordinated action to reduce fire use, strengthen forest protection policies, and support local and Indigenous stewardship efforts.
It also highlights the need for enhanced international climate finance mechanisms that recognise and address forest degradation, not just deforestation.
The study is published in Biogeosciences.
