A holistic approach to assessing REDD+ forest loss baselines through ex post analysis

The implementation of REDD+ (Reducing Emissions from Deforestation and Forest Degradation) projects has become a key Nature Based Solutions strategy to protect at-risk forests using the sale of verified emission reductions (carbon credits) as financing, generated by reducing forest loss against counterfactual baseline scenarios. Controversy over the reasonableness of such baseline scenarios has thrown this nascent market mechanism into disarray. While new technical approaches to baseline-setting that promise wider market acceptance are set to roll out in the coming years, existing projects are becoming unviable, as carbon credit buyers reduce investment due to lost confidence in the integrity of emissions reduction claims. Transparent, reproducible methods to assess existing REDD+ project baselines are needed in order to provide a clearer picture of the real impact of projects, and provide an objective basis on which investment decisions can be made today. Here we introduce such a method. In contrast to existing studies which utilize only one method to create a single ‘control,’ we integrate actual forest loss rates from a variety of control sites to establish a ‘zone of reasonable accuracy (or ZORA)’. Application of our method in Cambodia, using two geospatial datasets (one global and one locally calibrated), shows that all three project baselines fall within or below ZORA. This approach is fully reproducible, and provides a transparent way for analysts to assess REDD+ baselines during this critical time when investment in forest protection must increase dramatically and without delay.