Although carbon offset programs generally have effective measures in place to assure that the emission reductions are not double counted, there are still some steps that credit buyers should take to make sure they have an exclusive claim to emission reductions. Key questions to ask include:
- When offset credits are retired, is the purpose of the retirement clearly indicated in a carbon offset program registry? Buyers should ask to see proof of offset credit retirement on the relevant registry – including certificate numbers or a transaction ID that match the quantity purchased – along with a clearly identified purpose and the beneficiary of the retirement.
- Were the offset credits issued for indirect emission reductions? Ownership claims are harder to police where they involve indirect emission reductions (i.e., reductions that occur at sources not owned or controlled by the project owners). Claims to these emission reductions are inherently riskier because there is always a chance that the entities who do own or control the sources may claim the reductions as well. Major carbon offset programs generally try to prevent conflicting claims by having project owners legally attest to having an exclusive claim to credited reductions. However, it can be difficult (if not impossible) to determine exactly where indirect reductions occur, making the truth of such attestations difficult to verify. Where risks of double claiming seem significant (for example, if GHG reductions occur in sectors with significant voluntary commitments or regulatory obligations), buyers should avoid offset credits associated with indirect reductions (e.g., from projects that displace fossil fuel emissions on an electricity grid).