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In the Amazon, deforestation and climate change lead to increased vulnerability to forest degradation, threatening its existing carbon stocks and its capacity as a carbon sink. We use satellite L-Band Vegetation Optical Depth (L-VOD) data that provide an integrated (top-down) estimate of biomass carbon to track changes over 2011–2019. Because the spatial resolution of L-VOD is coarse (0.25°), it allows limited attribution of the observed changes. We therefore combined high-resolution annual maps of forest cover and disturbances with biomass maps to model carbon losses (bottom- up) from deforestation and degradation, and gains from regrowing secondary forests. We show an increase of deforestation and associated degradation losses since 2012 which greatly outweigh secondary forest gains. Degradation accounted for 40% of gross losses. After an increase in 2011, old-growth forests show a net loss of above-ground carbon between 2012 and 2019. The sum of component carbon fluxes in our model is consistent with the total biomass change from L-VOD of 1.3 Pg C over 2012-2019. Across nine Amazon countries, we found that while Brazil contains the majority of biomass stocks (64%), its losses from disturbances were disproportionately high (79% of gross losses). Our multi-source analysis provides a pessimistic assessment of the Amazon carbon balance and highlights the urgent need to stop the recent rise of deforestation and degradation, particularly in the Brazilian Amazon. [ABSTRACT FROM AUTHOR]

Aim: The aim was to evaluate fire activity for the entire Amazon and Amazon regions within each country/department from 2003 to 2020, assessing the potential contributions of drought and deforestation and contrasting 2020 with the previous years. Location: Amazonia sensu lato. Time period: Annually from 2003 to 2020. Major taxa studied: Terrestrial plants. Methods: We collected time series of MODIS active fire detections and burned area and assessed the yearly burned area of several land‐use/land‐cover types. We also divided the Amazon territory into 10 km × 10 km grid cells to identify annual anomalies in active fire occurrence, rainfall, maximum cumulative water deficit (MCWD) and deforestation. Rainfall and MCWD anomalies for a given cell each year consisted of annual values at least one standard deviation below average for that cell from 2003 to 2020, whereas fire and deforestation anomalies had annual values at least one standard deviation above the average for that cell. Results: Brazil and Bolivia have contributed, on average, >70% and about 15%, respectively, of annual active fire detections in the Amazon, in addition to more than half and about one‐third of annual burned areas in the region. On average, 32% of annual burned areas in the Amazon have consisted of agricultural lands, 29% of natural grasslands and 16% of old‐growth forests. The annual extent of areas with fire anomalies was significantly associated with the annual extent of areas with deforestation anomalies, but not significantly associated with the annual extent of areas experiencing water deficit anomalies. In 2020, the total burned area in the Amazon was the greatest since 2010, and the ratio of burned area per active fire was the second greatest of the time series, despite a much lower extent of areas with anomalously high water deficit in comparison to the 2015–2016 megadrought. Main conclusions Our findings suggest that the majority of anomalously high fire occurrences in the Amazon since 2003 did not occur in anomalous drought conditions. The intensification of agricultural fires and deforestation aggravated the burning of Amazonian ecosystems in 2020. [ABSTRACT FROM AUTHOR]