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Abstract
Independent evaluations have shown substantial over-issuance of REDD+ (Reducing Emissions from Deforestation and Degradation) credits traded on the voluntary carbon market. To improve credit integrity we need to synthesise these evaluations to understand the additional forest conservation achieved by first-generation REDD+ projects, and explore the mechanisms by which over-crediting occurred. We bring together six independent ex-post evaluations of avoided deforestation by 44 REDD+ projects. These consistently show that most projects successfully reduced deforestation, but they also claimed an aggregate of 10.7 times more avoided deforestation than independent evaluations indicate is justified. This discrepancy is not an artefact of which forest cover layer is used but is linked to selection bias in projects’ choices of control areas and modelling approaches. Given the need to close the forest finance gap, there is unwillingness to abandon the potential of the voluntary carbon market because of past failures. Current initiatives which transfer assessment to unconflicted parties and eliminate methodological flexibility is critical but insufficient. Ex post certification against a credible counterfactual is also necessary to ensure sufficient integrity in carbon markets for them to contribute to the vital task of slowing deforestation.
Supplementary materials
Title
Supplementary information for learning lessons from over-crediting to ensure additionality in forest carbon credits
Description
S1. Contrasting methods to assess REDD+ impact
- Certification methods
- Quasi-experimental methods
S2. Projects included in each analysis
S3. Over-crediting ratio labelled with VERRA project ID
S4. Differences in remotely sensed deforestation in project areas when including other forest types in the forest cover definition
S5. Comparing differences in control and project areas in their exposure to drivers of deforestation
S6. Differences in estimates produced by alternative certified modelling approaches
S7. Differences in control area deforestation when including degraded forest in the forest cover definition
S8. Consistency of over-crediting by country
S9. Avoided deforestation area calculations
S10. Compound annual deforestation rates
S11. Above Ground Biomass densities for ACC forest cover
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