In the REDD: a third of the Amazon degraded by human activities

A new study co-authored by BeZero scientist Dr Camila Silva reveals that the extent of forest degradation in the Amazon may exceed that of deforestation, bringing about as much biodiversity and carbon loss as deforestation itself.

The review, featured this week on the cover of Science Magazine, synthesizes the causes and impacts of forest degradation across the entire Amazon rainforest. Projections to 2050 indicate that degradation by disturbances, such as fire and extreme drought, will remain major sources of carbon releases to the atmosphere, independent of deforestation trajectories.

To evaluate changes in forest carbon stocks, deforestation and degradation must be differentiated. Deforestation is defined as the complete, or near-complete, removal of trees and conversion to another land use. In other words, forest to non-forest. Forest degradation is more subtle and complex, defined as a transitory or long-term deleterious change in forest condition that impacts forest functions, properties or services.

While the clearance of dense, evergreen forest can be reliably detected by Earth observation systems, forest degradation is more difficult to monitor remotely, and is frequently omitted from carbon accounting. For participants in the Voluntary Carbon Market (VCM), this has important implications for over-crediting risk, non-permanence and unquantified leakage. You can learn more about how forest degradation informs our carbon ratings in our webinar with Dr Kirti Ramesh and Dr Niels Andela.

REDD+ activities aim to Reduce Emissions from Deforestation and forest Degradation. There are currently at least 38 REDD+ projects registered in the Amazon region, the majority in Brazil and Peru, with another 13 in the registry pipeline. Only a small minority of these projects adequately address the second ‘D’.

For example, among 17 Amazonian REDD+ projects with a BeZero Carbon Rating, only four account for carbon emissions from forest degradation in their credit issuance.

The Science review focuses on four key human-induced disturbances that cause forest degradation: fire, timber extraction, edge effects, and extreme drought. To understand the impact of these disturbance mechanisms on carbon and biodiversity, both the extent and severity were investigated.

Between 2001 and 2018, over 5% of the Amazon rainforest was degraded by fire, timber extraction and edge effects combined. The total area affected is around 1.5 times the size of the United Kingdom (36 million hectares), more than the total deforested area over the same period. When drought is included, the area affected increases to ten United Kindoms (250 million hectares), or 38% of the remaining forest area.

The severity of these disturbances varies. A single understory fire can reduce aboveground carbon stocks by 13% to 50%. Edge effects are second in terms of severity, reducing carbon stocks by 23% to 35%, followed by timber extraction (4% to 35%) and extreme drought (1% to 8%). Biomass recovery times vary, but are significant on the decadal timescales of REDD+ crediting periods and permanence commitments.

At BeZero, we consider each of these disturbance mechanisms in our approach to carbon ratings, as well as the underlying drivers: demand for land and resources, governance, demography, and climate change. 

We are controlling for edge effects in our statistically-matched dynamic baselines and monitoring fire and drought across all nature-based carbon projects. We are also working through international partnerships to advance scientific understanding of how carbon and biodiversity are impacted by disturbance.

Across the VCM, we find large differences in risk from both deforestation and forest degradation. The scale and severity of degradation in the Amazon highlights opportunities for carbon projects to improve land management, for the benefit of climate, biodiversity and people. Like deforestation, however, curbing degradation requires that it be seen, understood, and effectively monitored.