Carbon Credit Due Diligence: A Checklist Built on the Registry Documents

1. Before you start: three identifiers

1. The registry ID, for example VCS-2455 on the Verra registry. Everything else is looked up from it. If an offer gives no registry ID, ask for it before anything else.
2. The standard, for example Verra's VCS, Gold Standard, the CDM, the Climate Action Reserve or ACR. Each one publishes its project documents on its own registry: Verra registry, Gold Standard Impact Registry, CDM project search.
3. The methodology and its version, for example ACM0001 v19.0. The methodology sets how the baseline, additionality and monitoring must be done. The version matters because rules change between versions, and labels such as the CCP label are approved for given versions.

How many documents CarbonMeld holds. Before you rely on the documents, check how many there are. As of 7 November 2026, in CarbonMeld's document data:

A low share can mean documents CarbonMeld has not collected yet, not documents the registry withholds. A project with few or no public documents is not necessarily a bad project, but you will have less to check, and you should ask the seller for what is missing.

2. The checklist, one document at a time

Step 1 — The project design document

(called the project description on the Verra registry)

• What it proves: what the project is, where, and how its reductions will be counted: the baseline, the additionality argument and the monitoring plan.
• What to check: the methodology and version it applies; the crediting period; how the baseline is set; how additionality is argued (an investment analysis with figures, or a barrier argument); the estimated annual reductions.
• Look twice if: the design document is not public; the project applied a methodology version that was no longer valid on the date it was registered or renewed its crediting period; the baseline assumptions are not explained; the additionality section has no figures where it claims a financial barrier.

Step 2 — The validation report

• What it proves: that an independent validation and verification body (VVB; a designated operational entity, DOE, under the CDM) checked the design against the methodology before the project was registered.
• What to check: who validated it and when; whether the findings raised during validation were closed; whether the report's conclusion is positive and unqualified.
• Look twice if: findings are left open; the conclusion is qualified; the report is missing although the project is registered (some programmes, such as the Climate Action Reserve, check eligibility at the first verification instead of in a separate validation report).

Step 3 — The monitoring reports

• What they prove: what the project actually did in each monitoring period, and how many reductions it claims for it.
• What to check: the period's dates; measured data against estimates; the reductions claimed against the design document's estimate; whether the monitoring periods are continuous.
• Look twice if: the claimed reductions jump far above the estimate without explanation; there are gaps between periods; the latest monitoring period is several years old.

Step 4 — The verification reports

• What they prove: that an independent body checked each monitoring report and confirmed the amount of reductions.
• What to check: the verified amount and the period it covers; the findings and how they were closed; whether a site visit took place; the verifier's opinion.
• Look twice if: the opinion is qualified; the verified amount differs from the monitoring report's claim and the verification report does not explain why; findings are left open. Our guide How to read a verification report goes through one real report page by page.

Step 5 — The registry's issuance and retirement records

• What they prove: how many credits were issued, for which vintages, and how many are already retired.
• What to check: that the credits issued for a period match the verified amount, less any deduction the programme makes (for example credits set aside in a buffer pool for non-permanence risk); the vintages on offer; how many credits of those vintages are still available; the serial numbers of the block you are offered.
• Look twice if: more credits were issued than were verified; the vintage on offer shows nothing available on the registry; the seller cannot give serial numbers.

3. The label checks

Labels are attached by registries and programmes, and they apply to specific credits, not to a project as a whole.

• ICVCM Core Carbon Principles (CCP) label. The ICVCM publishes which crediting programmes and methodology categories it has approved (ICVCM assessment status). An approved methodology is not enough: the registry attaches the CCP label to the credits themselves, so check that the units you are offered carry it.
• CORSIA eligibility, for airlines. ICAO lists the programmes whose units can be used, and for which compliance periods. Within each programme, ICAO's list sets the eligible unit dates and excludes some types of units, and units from 2021 onward need the host country's authorization (ICAO, CORSIA Eligible Emissions Units; ICAO summary table, April 2026). On the Verra registry, credits of vintages from 2021 onward need an Article 6 authorization label to be eligible for CORSIA (Verra, 9 April 2026).
• Article 6 authorization and corresponding adjustment. If you need a credit that the host country will not also count towards its own target, check the registry for an Article 6 authorization and, where shown, a corresponding adjustment.

4. After you buy

• Retirement in your name. A credit counts for your claim only once it is retired, and the public retirement record should name your organisation as the beneficiary.
• Serial numbers. Keep the serial numbers of the retired block, and check them on the registry's public retirement record.
• The claim you make. Check that the claim matches what the credits are (a reduction or a removal, labelled or not) and the rules of the claim you want to make.

5. How CarbonMeld's project pages show these documents

A CarbonMeld project page with a current analysis says how many of the project's registry documents CarbonMeld holds and how many of them the analysis read, for example «24/24 registry documents read» on the Haicheng Landfill Gas Power Generation Project (VCS-2455), as read on 7 November 2026. Where the data exist, the page also shows:

• the registry's labels (CCP, CORSIA, Article 6), with their source and the date they were read;
• the methodology version that each monitoring, verification and issuance document states, by period;
• the credits issued, retired and available, by vintage.

Pages of projects with a current assessment also show CarbonMeld's overall score, with its confidence, method version and date. The score is CarbonMeld's own document-based assessment, for information only: it is not investment advice, and it is not a rating from the registry or from the standard. Our guide Carbon credit ratings explained shows how to read it. To start from a project, use the project search.

• Search a project
• How to read a verification report
• Carbon credit ratings explained
• How to sell carbon credits
• Our methodology