Every claim a company makes about carbon credits rests on one entry in a database most buyers never open. That entry, in the registry of the standard that issued the credit, shows whether the tonne exists, who owns it and whether it has been used. A PDF certificate is a summary of it, not the evidence itself.
A carbon credit registry is the public database in which a standard records every credit it issues, with its project, vintage, serial number, holder and status. Retirement is the registry entry that takes a credit out of circulation permanently and names the company it was used for. This article explains what registries record, how transfers and retirements work, and how to check a retirement yourself in five minutes.
What a carbon credit registry records
A registry has two jobs: keep a public record of each project, and keep an exact record of each credit so the same tonne cannot be sold or claimed twice.
For each project it shows the registration documents: the project design, the validation report, monitoring and verification reports, and the methodology. For each credit it records:
a serial number, usually issued in blocks, that encodes the project, the vintage and the position of the credit in the block,
the vintage, the year in which the reduction or removal took place,
the account that holds it, from the developer’s issuance account to a trader’s or buyer’s account,
its status: active, retired or cancelled, sometimes with labels such as the ICVCM’s CCP label or eligibility for CORSIA.
The step-by-step life of a credit, from project design to issuance, is covered in how carbon credits work. This article picks up at issuance.
The main registries
Most standards run their own registry. The ones a European buyer meets most often:
Standard | Registry | Typical credits |
|---|---|---|
Verra (VCS) | Verra Registry | forest protection, reforestation, cookstoves, renewables, blue carbon |
Gold Standard | Gold Standard Impact Registry | cookstoves, water, renewables, reforestation |
Puro.earth | Puro Registry | biochar, enhanced rock weathering, geological storage (best Puro.earth projects) |
Isometric | Isometric Registry | biochar, enhanced rock weathering, direct air capture (best Isometric projects) |
ACR and Climate Action Reserve | their own registries | mainly North American projects |
Plan Vivo | Plan Vivo registry | community forestry and agroforestry |
Credits stay in the registry of the standard that issued them; they do not move between registries. How the standards themselves differ is covered in carbon credit standards compared.
Transfer, retirement and cancellation
Three registry actions are easy to confuse:
Transfer moves a credit from one account to another. The credit stays active and can be sold again. Most credits change hands several times before anyone uses them.
Retirement permanently takes a credit out of circulation for a stated beneficiary and purpose. A retired credit can never be transferred or sold again. This is the only action that lets a company claim the tonne.
Cancellation also removes a credit from circulation, but for other reasons: to correct an error, to cover a reversal from a buffer pool, or under some compliance schemes.
Many buyers never hold a registry account. Their supplier retires the credits on their behalf, which is normal practice, as long as the retirement names the buyer as beneficiary.
What a good retirement record shows
A retirement record should let a third party, such as your auditor, a journalist or a customer, confirm your claim without asking you. Look for:
Project name and ID, matching the project you were offered.
Serial number range, so the exact credits are identified.
Vintage, matching the quote.
Beneficiary: your company’s legal name, not the supplier’s.
Purpose or reporting year, for example “retired on behalf of [company] for 2025 emissions”.
Retirement date, ideally within the reporting period you claim for.
If one of these is missing, ask for it to be corrected before you publish anything. Under SBTi’s Corporate Net-Zero Standard V2.0, removals used for its requirements have to be retired in the company’s name and not claimed by anyone else (SBTi carbon removal requirements), and the same logic applies to any claim.
Tip from Bernard de Wit, Founder of Regreener: “Before you sign, ask how the credits will be retired and in whose name. 'We retire them in our general account and send you a certificate' is the answer to avoid. You want a registry link with your company’s name on it, so that anyone can check the claim without calling us.”
How to check a retirement yourself
Every major registry has a public search. Checking a retirement takes a few minutes:
Open the registry of the standard named on your certificate.
Search for the project ID and open the project page.
Go to the list of retirements (sometimes called retired or cancelled units) and filter on your company name or the serial numbers on your certificate.
Check that the serial range, vintage, quantity and beneficiary match what you paid for.
Save the link or a screenshot with the date, and file it with your sustainability report.
If you cannot find the retirement, or it sits under another name, raise it with your supplier straight away. A certificate that cannot be matched to a registry entry does not prove anything.
Registry risks a buyer should know
Credits held by intermediaries. Until retirement, credits sit in whoever’s account bought them last. If a supplier sells you credits it has not yet bought, there is nothing in the registry to check. Ask which account the credits are in before you pay (carbon credit trading explained).
Buffer credits are not for sale. Projects with reversal risk deposit part of their credits in a pooled buffer account. Buffer credits are not regular credits and cannot be sold or retired by buyers (permanence and buffer pools).
Tokenised credits. Some platforms sell digital tokens that represent credits. Verra banned tokens based on retired credits in 2022, because a retired credit must stay out of circulation. If you buy a token, check which registry credits sit behind it and who retires them.
Double counting across systems. A tonne can be recorded in a standard’s registry and, for Article 6 transfers, in national registries too. The Climate Action Data Trust, set up by IETA, the World Bank and Singapore, links registry data across systems to make double counting visible; it was moving registries onto a new data model in the first half of 2026.
What to ask your supplier
Which registry and project ID will my credits come from?
Can you share the serial number range before I pay?
Will you retire them in my company’s name, with the purpose and year?
When will I receive the registry link?
Are any of the credits held by another party until delivery?
Our full list of questions to ask a carbon credit supplier covers quality and pricing as well. At Regreener, every retirement is made in the client’s name and shared as a registry link.
“A registry entry is the one piece of carbon credit evidence nobody can argue with. Projects, methodologies and ratings are all open to debate. Whether a specific tonne was retired for your company on a specific date is a fact anyone can check.”
Bernard de Wit, Founder of Regreener
Want registry proof for every tonne?
We retire every credit in our clients' names and share the registry link, so your claims can be checked by anyone.
