The International Carbon Registry (ICR) put its 2026 program update into effect on October 9, revising five core documents and shifting the program's methodology foundation from the Clean Development Mechanism (CDM) to the Paris Agreement Crediting Mechanism (PACM).

The update covers the registry's main requirements, methodology rules, the methodology approval process, definitions, and validation and verification specifications. ICR released updated project, methodology and reporting templates alongside the documents.

The ICR board approved the final version on October 1, after a month-long public consultation that closed on August 12 and a separate technical consultation with approved validation and verification bodies.

The headline change is structural: active CDM methodologies will now serve as good-practice guidance rather than the program's primary methodology basis, with PACM taking that role.

What changes for project developers?

The revisions tighten several areas that have long been pressure points in carbon markets:

• Leakage: clearer definitions and requirements for activity-shifting, market, and ecological or biophysical leakage.
• Baselines: new requirements for reassessing baselines and making downward adjustments.
• Credit ownership and double counting: revised provisions governing who owns credits and how double counting is prevented.
• International transfers: rules now extend beyond the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA).

In plain terms: projects will face harder tests on whether their claimed reductions hold up when activity simply moves elsewhere or baselines drift.

What does the update demand from verifiers?

The verification specifications raise the bar for auditors. Validation and verification bodies must now hold ISO 14065 accreditation from an accreditation body belonging to the International Accreditation Forum or the Greenhouse Gas Accreditation Consortium. They must also identify which accreditation they used for each engagement.

The rules add more detailed criteria for materiality, sampling, site visits, findings, opinions, impartiality and competence. Scientific integrity assessment remains within the scope of validation and verification bodies, but with additional reporting requirements attached.

For verification firms, the message is blunt: accreditation alone isn't enough — engagement-level disclosure and tighter audit discipline are now written into the specs.

Which deadline applies to which project?

ICR has staggered the transition:

• New validation engagements beginning on or after November 1 must use version 6.2 of the main requirements.
• Earlier engagements may continue under version 6.1 until February 28, 2027.
• Registered projects using version 6.0 or later must adopt version 6.2 at their next verification.

That gives existing projects a runway, but not an open-ended one — the next verification cycle is the trigger point.

What about CORSIA eligibility?

ICR said its application for CORSIA eligibility for the 2027–2029 period remains under consideration and has not been determined. The outcome matters for airline-sector demand, and the registry's alignment with PACM — the Paris-era framework — signals where it expects eligibility decisions to land.

The milestone to watch: whether ICR secures CORSIA eligibility for 2027–2029, a decision that will shape demand for credits issued under the new rules.