Using Satellite-Derived Data to Understand Land Cover Drivers of Fire Ignition and Spread in the Brazilian Amazon

Fire in the Brazilian Amazon biome has been shown to be largely anthropogenic and is linked to a pattern of deforestation and agricultural expansion. Burning has been on the rise in the past decade, with thermal anomalies suggesting that the year 2020 had the second-highest number of fire detections since 1998, followed only by 2019. Although Brazilian national policy has banned human-caused fires in natural vegetation or during specific times of year, it fails to account for fires that escape their intended boundaries, or uncontrolled fires. Studies have shown that burned area from uncontrolled fires, which often start in pastureland and 'leak' into surrounding forest, may even be larger than the area of intentional deforestation. Uncontrolled fires result in damage to crops or grazing land, disturb forest ecosystems, and increase carbon emissions. To better understand the land cover drivers of fire spread, we used fire event data derived from Visible Infrared Imaging Radiometer Suite (VIIRS) imagery and the Global Fire Atlas' algorithm to analyze patterns of fire event ignition and spread across land cover classes in the Brazilian Amazon during the year 2020. Specifically, we investigated the relative frequency and temporal patterns with which fire events are spreading between land use land cover (LULC) classes, which LULC types are associated with fire ignitions, and the land cover types that fires are spreading to and from. We also provide an estimation of potential carbon emissions resulting from 2020 fires. We find a high rate of fire spread between land cover types. This indicates that policy targeting access to and use of containment methods will be beneficial in the face of future climate change. Understanding fire spread dynamics can provide context and guidance for the allocation of fire-fighting or fire-reduction resources on the ground and is essential for effective carbon budgeting by Amazonian countries like Brazil.