How could the concept of an "overall mitigation in global emissions" (OMGE) be operationalized under the Paris Agreement?

The Paris Agreement’s Article 6 establishes a new framework for using international car-bon market mechanisms. The primary objective of the approaches under Article 6 is to facilitate voluntary cooperation between Parties, to allow for higher ambition and to pro-mote sustainable development and environmental integrity. Moreover, Article 6.4 establishes the concept of delivering an “overall mitigation in global emissions” (OMGE).