CER

CERs (Certified Emission Reduction) are carbon credits ratified in the Kyoto Protocol and certificates issued by the United Nations to member countries. CERs are created due to projects that reduce greenhouse gas emissions using CDM (Clean Development Mechanism). Emission offsets through CERs can be counted toward meeting emission reduction targets by countries that are members of the EU ETS market. CERs can be purchased on the primary or secondary market (resold).

Sources:

1. https://en.wikipedia.org/wiki/Certified_Emission_Reduction
2. https://tergo.io/blog/carbon-offsetting/comparison-of-carbon-credits-cer-ver-ter/