A study reveals that fire emissions in the Amazon and Cerrado are largely driven by the smoldering combustion of woody debris. This crucial discovery highlights the significant influence of fuel characteristics on fire emissions, with wide-ranging implications for global carbon cycles, air quality and biodiversity.

The research tackles key uncertainties in fire emission inventories by integrating advanced Earth observation techniques with innovative modeling approaches.

By leveraging satellite data and fire models, scientists analyzed the intense 2020 fire season in the Amazon and Cerrado regions of South America. Their analysis also incorporated detailed information on fuel types, moisture conditions and burning behavior.

Their findings, published today in Nature Geoscience, are thanks to the international Sense4Fire project led by the Dresden University of Technology (TUD) in collaboration with the Royal Netherlands Meteorological Institute (KNMI), BeZero Ltd., and other institutes.

According to the research, woody debris accounts for up to 75% of the total burned live and dead biomass in these biomes, contributing to disproportionately high emissions of carbon monoxide and other air pollutants.

In addition, the study estimates that during 2020, wildfires in the Amazon consumed approximately 372 million tons of dry biomass, resulting in carbon monoxide emissions of about 40 million tons.

Matthias Forkel, from TUD and lead author, said, “We’ve demonstrated how the burning of dead wood, especially in tropical forest areas, results in smoldering combustion that produces significantly more carbon monoxide than fires in savannah ecosystems.

“This understanding is crucial for improving fire emission inventories and global climate models.”

The study also incorporates observations from the Copernicus Sentinel-5P mission, analyzed by KNMI, to validate and refine emission estimates.

Stephen Plummer, ESA Earth Observation Applications Scientist, noted, “The findings highlight the significant impact of woody debris in intensifying fire emissions and hence air pollution in fire-prone areas like the Amazon rainforest and Cerrado savannas, where deforestation and human-caused fires are becoming more frequent.”

The data are publicly available at TUD’s OPARA data repository.