Deforestation and agricultural fires: how land management in South-West Pará, Brazil, responded to political changes from 2014 to 2020

Abstract

Agricultural expansion and fires cause substantial losses of the Amazons biodiversity and are responsible for severe greenhouse gases emissions. In particular the increase of deforestation and fires since 2019 raised the concerns about an irreversible destruction of the Brazilian Amazon. Nevertheless, it often remains unclear how different stakeholders contribute to the observed changes in deforestation and burning. Our goal was therefore to better understand these changes across different land tenure- and farm systems and between the terms of President Rousseff, Temer and Bolsonaro. We assessed the occurrence of deforestation and burnt areas in south-west Pará, a region that is known for its high deforestation rates and raised media attention in 2019, when agricultural producers promoted a “Day of Fire” in response to President Bolsonaro’s call to use the Amazon more economically.

The spatial resolution of many fire- or burned area products is often very coarse and makes it difficult to distinguish between fires for deforestation and fires for agricultural land management. We therefore used the Framework for Operational Radiometric Correction for Environmental monitoring (FORCE) to create an analysis-ready time series of Landsat and Sentinel-2 observations with 30m spatial resolution from 2014 to 2020. From this time series we derived and classified clear observation sequences using a Random Forest and translated the class probabilities into annual COS scores (COS), from which we derived annual maps of burnt areas and land-cover. This reconstruction of the deforestation and fire history was then evaluated using quasi-experimental methods to determine the average treatment effect of the presidencies of Dilma Rousseff, Michel Temer and Jair Bolsonaro across all tenure systems and farm sizes.

Deforestation nearly quadrupled to 1,201 km², particularly during Bolsonaro in undesignated areas and conservation units, and on medium-sized farms (p < 0.001). Burning increased to 4,805 km² and in all tenure types (p < 0.001), and mostly occurred in already deforested land ( > 80%). The increase was strongest in agrarian settlements and conservation units, and on medium and large farms. Our observations show the importance to clarify land-tenure and re-strengthen disincentives of environmental infractions, which have been weakened specifically under President Bolsonaro. More broadly, our approach shows the suitability of combining maps of land-use changes and burnt areas with medium to high spatial resolution with quasi-experimental methods for improving our understanding of how political changes influence the land-use of different agricultural stakeholders.