What are ex-ante carbon credits and why are they risky?

08 November 2026

Ex-ante carbon credits represent emissions reductions that a project expects to deliver in the future, not reductions it has already achieved and verified. Buying one means you are funding a promise, not paying for a tonne of CO₂ that has already been kept out of the atmosphere. That promise may or may not be kept. The risk is that the reductions never happen, the project fails, or the actual outcome falls far short of what was forecast.

How an ex-ante credit differs from a regular (ex-post) credit

A standard carbon credit is issued after a project has completed a monitoring period and a third-party verifier has confirmed the actual emissions reductions. That credit is ex-post - it refers to real, measured, and verified tonnes. It exists on a registry with a serial number, and its vintage year tells you when the reductions occurred.

An ex-ante credit is issued before any verification takes place, based on projected reductions over the project's lifetime. The project developer estimates how much CO₂ will be avoided or removed, then sells credits against that estimate years before the reductions happen.

Some ex-ante credits later become ex-post credits: if the project achieves its planned reductions and passes verification, forward-sold credits may be swapped for verified ones. Many do not complete that transition.

Why ex-ante credits exist

Projects - especially forestry, renewable energy, and clean cookstove projects - require upfront capital. A developer might need millions of dollars to plant trees, install solar panels, or distribute stoves before any emission reductions occur. Selling ex-ante credits provides that early funding.

Carbon credit buyers have used ex-ante credits to pre-purchase credits at a discount, betting the project succeeds and the credits appreciate. Others buy them as a form of donation with a potential environmental return. Neither approach guarantees the claimed emissions impact.

The specific risks

1. Non-delivery

The project may never generate the promised credits. Common failure modes:

• Reversal: Trees planted for a forestry project burn, die from drought, or are illegally logged. The stored carbon returns to the atmosphere.
• Overestimation: The initial projections were optimistic. Actual reductions after several years turn out to be 30 - 50% lower than forecast.
• Abandonment: The developer runs out of money, leaves the area, or ceases operations. No monitoring, no verification, no credits.

A buffer pool can cover some reversal risk for certain ex-post credits. Ex-ante credits generally lack that protection because there is nothing yet to buffer.

2. Credibility gaps in projections

Ex-ante calculations rely on assumptions about future conditions: weather, economic growth, local cooperation, regulatory stability. Small errors in the baseline or leakage assumptions compound over years. A 5% overestimate each year can become a 40% gap over an eight-year crediting period.

Many ex-ante project documents include phrases such as "expected to reduce," "projected to avoid," or "estimated to remove." None of these is a guarantee.

3. Registry and market risks

Most major carbon registries (Verra, Gold Standard) do not issue ex-ante credits with the same serial numbers they use for verified credits. Some registries do not issue them at all. This means:

• Tracking an ex-ante credit back to a specific verified tonne is often impossible until conversion happens.
• If the project never converts, the ex-ante token on a blockchain may remain permanently unbacked by any real emissions reduction.
• Double counting becomes harder to detect because the ex-ante token exists before the registry has a verified serial number to anchor it.

4. Tokenisation makes the risks harder to see

When an ex-ante credit is tokenised, the blockchain record shows a token that looks like a carbon credit. Its metadata may describe the project and the projected reductions, but it will lack a retirement date or a verified serial number. Buyers who do not check the registry may mistake it for a real verified credit.

How to identify an ex-ante carbon credit token

Three checks can tell you whether a token represents future, unverified reductions:

1. Look for a verified serial number. If the token metadata lists a registry serial number, verify that number on the registry's public interface. Ex-ante credits often have project numbers but no individual credit serials.
2. Check the vintage year. A token whose vintage year is later than the current year is almost certainly ex-ante. Verified credits are issued after the reductions occur, so their vintage year is in the past.
3. Find the project's verification status. Use the project ID (not the token contract) to search the registry. If the registry shows "under development," "not yet verified," or no monitoring reports, the credit is ex-ante.

When an ex-ante credit might be acceptable

Some large institutional buyers with long-term relationships and deep due diligence capacity purchase ex-ante credits from developers they have worked with for years. They treat the purchase as a conditional pre-financing arrangement, not a final offset. Those buyers verify conversion performance annually and have contractual recourse if delivery fails.

For a retail buyer or a company making a public emissions claim, ex-ante credits carry unacceptable reputational risk. A claim based on unverified future reductions can be challenged as misleading or greenwashing. The voluntary carbon market's integrity guidance - from groups such as the Integrity Council for the Voluntary Carbon Market (ICVCM) - strongly discourages using ex-ante credits for offsetting claims.

Bottom line

An ex-ante carbon credit is a bet on a project's future success, not a receipt for past action. The token may look real, but what it represents is uncertain until verification happens. Treat any carbon credit token without a verified registry serial number and a past vintage year as unconfirmed - and unsuitable for any claim that you have already offset emissions.

Back to carbon credits