Certified emission reduction
Certified emission reductions (CERs) are a type of emission unit (or carbon credits) issued by the Clean Development Mechanism (CDM) Executive Board for emission reductions achieved by CDM projects and verified by a DOE (Designated Operational Entity) under the rules of the Kyoto Protocol. CERs can be used by Annex 1 countries in order to comply with their emission limitation targets order to comply with their obligations to surrender CERs or emission reduction units (ERUs) for the CO2 emissions of their installations.
Source: Wikipedia — Certified emission reduction (CC BY-SA 4.0)