Carbon crediting programs apply several methods to ensure that credits convey an exclusive claim to avoided GHG emissions or enhanced removals.
Double issuance is addressed primarily by:
- Ensuring that carbon credits are only issued after program approval of verification reports and other supporting documentation.
- Checking that the accounting boundaries used to quantify avoided GHG emissions or enhanced removals do not overlap with other projects.[1]
Double use is addressed primarily through registry systems that assign unique serial numbers to individual carbon credits, track their transfer and ownership, and record the purpose of their use and on whose behalf they were retired.[2]
Double claiming is addressed through:
- Restricting the eligibility of project types (e.g., excluding those that are known to be subject to GHG reduction mandates or competing claims); and/or
- In some cases, project developers are required to sign legal attestations asserting exclusive claims to credited avoided emissions or enhanced removals and agreeing to legally convey such claims to the buyers of carbon credits (programs may differ in their specific legal requirements).
[1] Procedures may include requiring project developers to sign legal attestations stipulating that they will not request issuance of carbon credits for avoided emissions or enhanced removals from more than one program (unless they are effectively “transferring” credits from one program to another).
[2] Some third-party programs, like Green-e Climate, provide checks on credit retirement steps for retail credit buyers. However, in most cases, this adds little value in terms of assurance beyond what carbon crediting programs already make available to any buyer in terms of retirement certification. In practice, programs do not always clearly indicate the purpose and beneficiaries of credit retirements.