For some time, the Clean Development Mechanisms (CDM) served as an international standard for offsets in the international carbon market. This market is now splintering. New emissions trading systems see the CDM only tepidly, are developing their own offset systems and the standard setting function of the CDM is in danger of being lost. On behalf of the German Emissions Trading Authority (DEHSt) at the Federal Environment Agency, adelphi researchers Aki Kachi and Dennis Tänzler, together with Wolfgang Sterk from the Wuppertal Institute, have examined these developments and the emerging alternative offset systems and suggest issues to be addressed if the CDM is to be reformed to continue to play its “glue” function in the international carbon market.