Methodological Problems Underlying Voluntary REDD+ Project Baselines Compromise the Environmental Integrity of Carbon Offsets

Abstract

The number of voluntary carbon-offset interventions seeking to reduce deforestation and forest degradation and generate carbon offsets, namely REDD+ projects, increased significantly over the past decade. Offsets are issued based on project performance in comparison to a baseline scenario representing the expected deforestation level in the project area in the absence of REDD+. Baselines from most ongoing REDD+ projects were established following four REDD+ methodologies approved by the largest voluntary market carbon offset certification scheme worldwide, the Verified Carbon Standard (VCS). These methodologies often rely on oversimplified assumptions about deforestation that remain overlooked by project developers, certification bodies, buyers, and the VCS itself. Here, we scrutinize what these methodological assumptions are and their implications for REDD+ project baselines. We adopt these assumptions to construct several alternative baseline scenarios for four VCS-certified projects and examine how they affect baseline deforestation. Overall, we observe large discrepancies among the projects’ baseline deforestation rates driven by the selection of the VCS-REDD+ methodology and their underlying assumptions, suggesting a lack of robustness and consistency across the baseline methods. Our results also call into question the additionality of carbon offsets issued based on these methodologies, compromising the integrity of carbon markets. New baseline methods need to be urgently developed if voluntary REDD+ projects are to reliably offset greenhouse gas emissions and contribute additionally to climate change mitigation.

Keywords: REDD+, Carbon credit, Baseline, Avoided deforestation, Nature-based solutions