An alternative way to mitigate non-additionality risks of carbon offsets

The market for carbon credits is riddled with problems. Despite lengthy and costly case-by-case approval processes, often too many credits are awarded per project (over-crediting), and many projects would have happened anyway (non-additionality). Here we investigate a novel additionality regime based on: (i) dynamic positive lists that define automatic eligibility criteria, specified by host country and by project type; and (ii) partial credit issuance to reflect context-specific non-additionality risks. We carry out simulation analysis, conducted on a synthetic project pool calibrated on historical data, to demonstrate that this approach performs better than current practice under most scenarios in terms of emissions reductions, cost efficiency, and resilience against systematic over-crediting. The findings support a standardised assessment approach over project-specific evaluation, and they call for more disaggregated analysis across heterogeneous contexts to mitigate regulatory biases and deliver a simpler certification process with better climate outcomes.