our results suggest the need for practical evaluations of mangrove-based carbon offsets, including rigorous local assessments of offsets as well as developing their robust verification and monitoring. Current policy programs, such as the Indonesia-Norway REDD partnership and the offset provision under California’s Assembly Bill 32, may already provide the necessary framework. For example, California has signed an agreement with Chiapas, Mexico, to provide forest offsets starting in 2015 (35). Our data suggest that carbon offsets from mangrove conservation in Chiapas could be competitive relative to the predicted permit price in California, but further study is needed.