Carbon loss from forest degradation exceeds that from deforestation in the Brazilian Amazon

TL;DR

This study reveals that in the Brazilian Amazon, forest degradation causes more carbon loss than deforestation, emphasizing the need for policy focus on degradation processes.

Contribution

It quantifies the relative impacts of forest degradation and deforestation on carbon loss using satellite data, highlighting degradation as the primary driver.

Findings

Forest degradation accounts for 73% of gross AGB loss.

Net AGB loss was significantly smaller in 2019 compared to 2015.

Gross forest area loss was higher in 2019, possibly due to policy changes.

Abstract

Spatial-temporal dynamics of aboveground biomass (AGB) and forest area affect the carbon cycle, climate, and biodiversity in the Brazilian Amazon. Here we investigate inter-annual changes of AGB and forest area by analyzing satellite-based annual AGB and forest area datasets. We found the gross forest area loss was larger in 2019 than in 2015, possibly due to recent loosening of forest protection policies. However, net AGB loss was three times smaller in 2019 than in 2015. During 2010-2019, the Brazilian Amazon had a cumulative gross loss of 4.45 Pg C against a gross gain of 3.78 Pg C, resulting in net AGB loss of 0.67 Pg C. Forest degradation (73%) contributed three times more to the gross AGB loss than deforestation (27%), given that the areal extent of degradation exceeds deforestation. This indicates that forest degradation has become the largest process driving carbon loss and should become a higher policy priority.