Reviewing and annotating documents at a desk, representing carbon offset project due diligence before purchase
Methodology & Standards

Carbon Offset Due Diligence: A Practical Checklist Before You Buy

Sep 01, 2026
Buyer's Checklist · Due Diligence · Market Integrity · ~12 min read · Published September 2026 · CRBN.CREDIT Intelligence Desk

Most carbon credit disasters that make headlines don't come from fraud. They come from a buyer who skipped questions a five-minute registry lookup would have answered. This is the checklist, in the order that actually matters.

Key Takeaways
  • Registry registration confirms a project met a methodology's paperwork requirements. It is not a quality signal on its own.
  • A large gap between credits issued and credits retired is worth investigating before it's worth dismissing, but it's always worth checking.
  • Additionality and permanence are separate questions. A project can pass one and fail the other.
  • The ICVCM's Core Carbon Principles now give buyers a concrete, checkable label, CCP-Approved, that didn't exist a few years ago.
  • Independent ratings exist precisely because registry approval and a project's own materials aren't sufficient on their own.

Why Registration Alone Isn't Enough

A project appearing in Verra's registry, or Gold Standard's, or any of the other major registries, tells you it met that registry's methodology for the category it's registered under. That's a real bar, but it's a paperwork bar. It says a project followed the correct process to get credited. It doesn't independently confirm the project delivers what it claims, doesn't compare it against other projects in the same category, and doesn't tell you anything about how the credits are actually being used after issuance.

Buyers who treat registration as the finish line are the ones who end up surprised later. Buyers who treat it as the starting filter, the thing that gets a project onto the list worth actually checking, make better decisions.

Step 1: Check Issuance Versus Retirement

This is the fastest, highest-signal check available, and it's the one buyers skip most often because it requires actually looking at the numbers instead of the marketing page.

Issued credits are how many tonnes a registry has credited a project for. Retired credits are how many of those have actually been claimed by a buyer and permanently taken out of circulation. A project can have a large issuance number and a much smaller retirement number, which isn't automatically a problem, some projects issue in large batches and retirements trail behind naturally, but it's a number worth looking at before buying, not after.

You can check any tracked project's real issuance and retirement figures directly in our carbon offset projects database, sourced from registry-reported data rather than a project's own materials.

Step 2: Confirm Additionality

Additionality asks one question: would this emissions reduction have happened anyway, without carbon credit revenue? A solar farm that was already fully financed and under construction before carbon credits entered the picture has a weak additionality case, the reduction was happening regardless. A project that only became financially viable because of carbon credit revenue has a strong one.

This is genuinely hard to verify from outside, which is exactly why it's worth checking rather than assuming. Look for the project's stated baseline scenario, what would have happened without the project, and whether that baseline is specific to the project's actual circumstances or a generic industry assumption.

Survey drone flying above forest canopy, representing independent monitoring and verification of carbon offset projects
Independent monitoring is what separates a verified claim from a stated one. Registry paperwork alone does not confirm delivery.

Step 3: Check for CCP-Approved Status

This is a newer, more concrete signal than it used to be. The Integrity Council for the Voluntary Carbon Market runs an Assessment Framework built around ten Core Carbon Principles, covering additionality, permanence, robust quantification, no double counting, and sustainable development safeguards.

It works as a two-tick system: first the crediting program itself (Verra, Gold Standard, ACR, and others) has to be CCP-Eligible at the program level, then specific methodologies within that program have to separately earn CCP-Approved status. Only credits issued under an approved methodology can carry the CCP label.

This matters practically because approval is granted methodology by methodology, not blanket-applied across an entire registry. Verra's newer landfill gas methodologies are CCP-Approved, for example, while many older REDD+ approaches are still under assessment or have been rejected outright. Checking whether a specific project's specific methodology carries CCP-Approved status is a faster, more concrete signal than trying to assess additionality and permanence entirely from scratch yourself.

Step 4: Assess Permanence Risk

Permanence asks how long the carbon actually stays out of the atmosphere. This varies enormously by project type, and it's a separate question from additionality entirely, a project can be genuinely additional and still carry real permanence risk.

Project typeTypical permanence horizonMain risk
Forestry / REDD+Decades, contractuallyFire, illegal logging, political reversal
Soil carbon / agricultureYears to decadesReversal if farming practices change
Biochar100 to 1,000+ yearsLow, but production quality varies
Direct air capture (geological)10,000+ yearsVery low, but capital cost is high

← Scroll table horizontally on mobile

Mist over dense forest slopes, illustrating permanence and reversal risk in forestry carbon credit projects
Forestry permanence is contractual, not physical. Fire, logging, and political reversal are the risks a buffer pool is designed to absorb.

Neither end of this table is automatically "better." A forestry project's shorter permanence horizon comes with a much lower price per tonne and often stronger co-benefits. A DAC project's near-permanent storage comes at a substantially higher cost. The right choice depends on what the credits are actually for. For a category-by-category breakdown of what each type costs and delivers, see our ranking of the 13 carbon credit types by price and permanence.

Worth knowing too: the ICVCM's framework requires at least a 40-year monitoring period and a buffer pool contribution of at least 20% of total credits issued for categories with high reversal risk, a concrete backstop against exactly this concern.

Step 5: Check for Independent Ratings

Registries approve methodology compliance. They don't rate project quality against each other. That's what independent rating agencies exist to do. BeZero Carbon, Sylvera, and Calyx Global all publish project-level ratings built specifically to answer the question a registry listing doesn't: how does this project actually compare to others in its category?

A project with no independent rating isn't automatically bad, plenty of solid projects haven't been rated simply because rating agencies haven't covered every project in the market yet. But a project actively avoided by every major rating agency, or rated and scoring poorly, is worth a second look before buying.

Step 6: Verify Location-Specific Risk

Country and region matter more than buyers often assume. A forestry project's fire risk, a jurisdiction's political stability, and a region's history of land tenure disputes all affect the real-world durability of a credit, independent of the project's own methodology or paperwork. Check where a project is actually located, not just what category it falls under.

Red Flags That Should Stop a Purchase

  • Issuance without retirement. Issuance numbers with no corresponding retirement activity over a long period, and no explanation available for the gap.
  • A template baseline. A baseline scenario that reads as a generic industry template rather than something specific to the actual project site.
  • No CCP status and no rating. No CCP-Approved status and no independent rating available, combined with vague or promotional-only project documentation.
  • Unaddressed location risk. A project location with known, documented permanence risk that isn't addressed anywhere in the project's own materials.
  • Urgency as a sales tactic. Pressure to buy quickly, "before the price rises" urgency has no bearing on whether a project is actually sound.

The pattern behind most bad purchases is not a sophisticated deception. It is a buyer who accepted a registry listing as the answer to a question the registry was never designed to answer. For documented examples of how this plays out, see our analysis of carbon credit fraud case studies.

Running due diligence on a specific project?
The CRBN.CREDIT projects database carries registry-reported issuance and retirement figures across 11,659 tracked projects and seven registries.

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Frequently Asked Questions

What's the single most important thing to check before buying a carbon credit?

Whether issued credits have actually been retired, not just issued. A project can be credited for millions of tonnes on paper while very little has been claimed and taken out of circulation. Issuance shows a registry approved the methodology, retirement shows credits are actually being used.

Does a project being registered with Verra or Gold Standard mean it's high quality?

No. Registration means a project met that registry's methodology requirements, it isn't a quality or integrity score. Two Verra-registered projects can have very different real-world outcomes. Registration is a starting filter, not an endpoint.

What is CCP-Approved status?

A label from the Integrity Council for the Voluntary Carbon Market confirming a specific methodology, not just a registry as a whole, meets its Core Carbon Principles for additionality, permanence, and quantification. It's granted methodology by methodology, so two projects on the same registry can differ.

What's the difference between additionality and permanence?

Additionality asks whether the emissions reduction would have happened anyway without carbon credit funding. Permanence asks how long the carbon actually stays out of the atmosphere. A project can be additional but not permanent, or permanent but not additional, both matter separately.

Should I trust a project's own sustainability claims?

Treat them as a starting point, not a conclusion. Independent rating agencies such as BeZero Carbon, Sylvera, and Calyx Global exist specifically because registry approval and a project's own marketing aren't sufficient signals on their own.

How do I check a specific project's actual issuance and retirement numbers?

Registry data is public. CRBN.credit's project database lets you look up any tracked project's registry-reported issuance and retirement figures directly, without digging through individual registry portals one at a time.

A note on this article. This checklist reflects general due diligence practice and doesn't substitute for a full independent rating or legal review on any specific transaction. It is for informational purposes and is not investment advice. Registry-reported figures referenced here come from public registry data, not from CRBN.credit's own assessment of project quality.