Recent trends in the fire dynamics in Brazilian Legal Amazon: Interaction between the ENSO phenomenon, climate and land use

Abstract

The Brazilian Legal Amazon is an extensive territory (5,088,668.25 km2) in which different factors (environmental and social) influence the fire dynamics of the region. This study aims to explain the seasonal patterns of meteorological variables, fire, land use, and carbon emissions and their inter-relationships, focusing on years of El Niño–Southern Oscillation (ENSO) occurrence. For this purpose, we used data from fire foci and burned area obtained by the Moderate Resolution Imaging Spectroradiometer sensor and meteorological variables from Reanalysis 2. The kernel density was applied to the fire foci, and Spearman correlation coefficient between the foci and the other variables (fire foci, burned area, carbon emissions, evapotranspiration, wind speed, relative air humidity, rainfall, soil moisture, maximum temperature, minimum temperature, and mean air temperature) and Mann Kendall test for soybean, corn and sugarcane crops were performed. The years considered as La Niña were those with the highest fire foci, burned area, and carbon emissions. Our results show that even in periods considered as low fire risk, forests may be vulnerable to fires due to interaction with other variables. Furthermore, we found a tendency to increase the area planted with soybean, maize, and sugarcane, which may lead to more deforested areas in the region if there is no support from public policies. The uncertainty of the Legal Amazon's behavior towards climate change, combined with possible setbacks in Brazilian environmental policy due to the current government, highlights the importance of studies that encompass several factors such as this one.