Delacote, Philippe, Chabé-Ferret, Sylvain, Creti-Bettoni, Anna, Duffy, Katharyn, Lott, Micah, Guizar-Coutiño, Alejandro, Filewod, Ben, Groom, Ben, Kontoleon, Andreas, LeVelly, Gwenole, L’Horty, Lara, Missirian, Anouch and West, Thales A. P. (2025) Restoring credibility in carbon offsets through systematic ex post evaluation. Nature Sustainability.

Abstract

A key factor undermining the credibility of carbon offsets is the evaluation of project baselines and their impact. The ex ante scenarios constructed by project developers in accordance with rules set by certification schemes have been challenged by ex post evaluations from scientists, who frequently document cases of credit allocations that overestimate the actual emission reductions. Increasing credibility requires methodologies that reliably measure project outcomes and prevent overcrediting—an objective that ex post evaluations may be well suited to achieve. We explore how systematic ex post evaluations could restore credibility to certification schemes in the voluntary carbon market.