Article 6 used to be a topic for climate negotiators. It now shows up in carbon credit quotes as “authorised”, “corresponding adjustment” or “Article 6-eligible”, usually with a higher price attached. Buyers need to know what those words mean, and whether they need to pay for them.
Article 6 of the Paris Agreement lets countries cooperate on emission reductions, including by transferring them across borders, with a corresponding adjustment so each tonne is counted once. It has two market tracks, bilateral cooperation under Article 6.2 and a UN-supervised crediting mechanism under Article 6.4, plus a non-market track under 6.8. This article explains how they work, where they meet the voluntary market, and when a company actually needs an authorised credit.
Why Article 6 exists: counting each tonne once
Under the Paris Agreement every country has a climate target, its nationally determined contribution (NDC). That creates a counting problem. If a forest project in country A sells a credit to a company or government in country B, and country A also counts the same reduction towards its own target, the tonne is claimed twice.
Article 6 solves that for international transfers. A host country can authorise a reduction for use outside its own target. When the authorised reduction is transferred, the host country applies a corresponding adjustment in its emissions accounting, adding the tonne back to its balance, so only the buyer counts it.
The Article 6 Observatory describes a corresponding adjustment as “an accounting safeguard, not a quality label” (Article 6 101). An authorised credit from a weak project is still a weak credit.
Article 6.2: bilateral deals and ITMOs
Article 6.2 allows countries to set up cooperative approaches, usually bilateral agreements between a buying and a host country. The Paris Agreement leaves the design to the countries; they agree which project types qualify, how units are authorised and how they are tracked.
A mitigation outcome that has been authorised and first transferred under such an approach is an ITMO (internationally transferred mitigation outcome). The first ITMO transfer took place in December 2023, from Thailand to Switzerland. By a UNFCCC update of June 2026, 40 countries were linked to cooperative approaches. Switzerland, Japan, Singapore and Sweden are among the most active buyer countries, and new arrangements keep being announced; Brazil and China, for example, were reported in September 2026 to be preparing an Article 6.2 agreement for COP31.
For a company, Article 6.2 matters mainly through the projects that sit in these agreements. Some voluntary-market projects are being authorised so their credits can be sold to governments or to compliance buyers, which takes supply away from voluntary buyers and supports prices for that kind of credit.
Article 6.4: the Paris Agreement Crediting Mechanism
Article 6.4 creates a single, UN-supervised crediting system, the Paris Agreement Crediting Mechanism (PACM), overseen by the Article 6.4 Supervisory Body. It is the successor to the Kyoto Protocol’s Clean Development Mechanism (CDM), and CDM projects can transition to it under stricter rules.
The PACM approved its first issuance in February 2026, for a transitioned clean-cooking activity in Myanmar. The Supervisory Body reported that the credited reductions were about 40% lower than older rules would have produced, mainly because of more conservative baselines (UNFCCC Article 6.4 news).
The PACM issues A6.4ERs, which come in two kinds:
Authorised A6.4ERs that the host country has approved for international use. They become ITMOs at first transfer and carry a corresponding adjustment.
Mitigation contribution units (MCUs), which are not authorised. They count towards the host country’s own target and can support results-based finance or contribution claims, but another country cannot use them for its NDC.
The PACM also builds in contributions most voluntary standards do not: a share of proceeds for adaptation, and a cancellation of part of the credits as an overall mitigation contribution, so not every tonne is used to compensate someone else’s emissions.
Article 6.8: non-market cooperation
Article 6.8 covers cooperation without trading: finance, technology transfer and capacity building. It does not create units and has no direct role in carbon credit purchasing.
Where Article 6 meets the voluntary carbon market
Most voluntary credits are not authorised and do not need to be. A credit issued by Verra or Gold Standard for a reduction in Kenya stays in Kenya’s national accounting, and the buyer makes a contribution claim: “we financed this reduction”. Nobody counts it twice towards a national target, because the buyer does not use it towards one.
Authorisation matters in four situations:
CORSIA. Airlines can only use units with host-country authorisation and a corresponding adjustment for their first-phase obligations (buying CORSIA credits).
Government buyers and carbon taxes. Countries buying ITMOs for their NDCs, and tax systems such as Singapore’s, which lets companies use eligible international credits from partner countries for up to 5% of their taxable emissions.
The EU after 2035. The EU’s 2040 climate law allows up to 5 percentage points of the 2040 target to come from high-quality international credits from 2036. The Commission’s July 2026 ETS proposal would set aside up to 260 million allowances to buy them (EU ETS explained).
Corporate claims that rely on exclusive ownership of the tonne, where a buyer wants to be sure no country counts the same reduction. Some companies ask for authorised credits for this reason, especially in long-term contracts.
For a European company making a contribution claim, which is what EU consumer rules steer towards from 27 September 2026, an authorised credit is not required (contribution claims).
Tip from Bernard de Wit, Founder of Regreener: “If a quote includes an Article 6 premium, ask what you will do with the authorisation. For CORSIA or a government buyer it is essential. For a contribution claim it mostly buys you a slower delivery and a higher price. Pay for it when your use needs it, and put the money into a better project when it does not.”
What authorisation changes in a contract
Authorised credits introduce risks that ordinary voluntary credits do not have, because they depend on a government act:
Authorisation risk. The letter of authorisation may be delayed, conditional or withdrawn. Check what the contract says if it does not arrive.
Corresponding adjustment timing. The adjustment appears in the host country’s reporting, often later than the credit is delivered. Ask how and when it will be evidenced.
Policy risk. Host countries can change which project types they authorise, or reserve them for their own target.
Price. Authorised credits generally trade at a premium over the same project’s unauthorised credits.
These terms matter most in multi-year deals. Our guides to carbon offtake agreements and offtake contract terms cover how to allocate them.
“Article 6 makes the carbon market more credible, because it closes the double-counting gap for international transfers. It does not make every credit better. We assess an authorised credit with exactly the same quality framework as any other credit, and only then look at what the authorisation adds.”
Bernard de Wit, Founder of Regreener
A quick reference
Term | What it means | Do you need it? |
|---|---|---|
Article 6.2 | Bilateral cooperation between countries | Only via projects in such deals |
Article 6.4 / PACM | UN-supervised crediting mechanism | Optional source of credits |
ITMO | Authorised mitigation outcome after first transfer | For NDC or CORSIA use |
Corresponding adjustment | Host country removes the tonne from its own accounting | When the use requires exclusive counting |
Authorised A6.4ER | PACM credit approved for international use | For compliance uses |
Mitigation contribution unit | PACM credit not authorised for international use | Suitable for contribution claims |
Offered credits with an Article 6 premium?
We assess the project behind the authorisation and tell you whether your intended use needs it.
