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The CORSIA emissions unit eligibility criteria that the TAB will apply for its 2026 assessments show much stricter and more specific requirements for host party attestation than for the first phase and, along with the tightening of other carbon credit integrity assessment criteria, will likely add further restrictions to supply in CORSIA’s second phase.
The TAB is no longer considering applications from emissions unit programs for eligibility under the first phase (2024-2026 compliance period), but successful applicants under the 2026 assessment cycle may be recommended to supply eligible units for the first phase.
In its last report to the council in August 2025, the TAB recommended four programs with approval to supply CORSIA-eligible units for the second phase: ACR, Architecture for REDD+ Transactions (ART), Gold Standard (GS) and Verified Carbon Standard (VCS). In addition to this, the TAB had given a nod to Isometric and Premium Thailand Voluntary Emission Reduction Program (Premium T-VER) under the first phase.
Additionally, the Forest Carbon Partnership Facility (FCPF) and the BioCarbon Fund Initiative for Sustainable Forest Landscapes (ISFL) remain under TAB’s consideration for the first phase and will receive a decision in TAB’s next recommendation to the ICAO council in March 2026. In its most recent recommendation report, TAB also invited Cercarbono to reapply for assessment directly under the second phase with a possibility of also providing supply under the first phase if successful.
TAB also held a webinar, “Understanding CORSIA Eligible Emissions Units,” on Wednesday February 18, wherein it explained operational procedures for the 2026 assessment cycle and said that the results of the assessment can be expected in the 239th Session of the Council, which will be held in October or November. Additionally, currently eligible programs have two deadlines to report material changes – April 25 and August 14.
The TAB, along with the call for applications, also released detailed CORSIA Emissions Unit Eligibility Criteria, which it will apply for its 2026 assessments. Juxtaposing these recent eligibility criteria with the criteria that were used to approve programs under the first phase (2024-2026 compliance period) will provide insights into the additional requirements for the issuing programs and potential supply barriers for the second phase (2027-2029 compliance period).
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TAB has further fleshed out requirements for the host party attestation and the procedures that the emission units program needs to have in place to ensure robust monitoring at each step of adjustment being applied by the jurisdiction, in accordance with the guidance for Article 6.2 that was agreed during Conference of Parties 28 (COP 28), 2023.
According to market participants, Letters of Authorization (LoA) and their insurability have been the biggest bottlenecks to supply in CORSIA phase one (2024-2026 compliance period). These additional LoA requirements, on one hand, will mean greater coordination and administrative efforts from the host country, which could draw out an already time-consuming process but could also help fast track insurance as the required additional details and monitoring will boost insurability.
The TAB requires emissions unit programs to have procedures in place that guide the host country’s attestation (also known as LoA) to specify and describe the steps taken by the host country to avoid double-claiming of the eligible mitigation unit under CORSIA as well as the host country’s NDC. Additionally, the host country attestation/ LoA should include not only the national point of contact, vintages and project activity type but also the CORSIA compliance cycle for which the units are authorized, the expected timelines for when the host country will apply and report the adjustments, the host country’s definition for “first transfer” and its chosen accounting method, consistent with the treatment of cooperative approaches under guidance for Article 6.2.
The program should also ensure that the host party attestations confirm that units used for CORSIA will appropriately be accounted for and not used toward any claims by the host country in achieving their NDCs or other targets/pledges.
The program should moreover put in place procedures to compare a country’s national accounting for emissions units with the volume of attested CORSIA-eligible units. Such procedures should specify the national reports that contain the country’s emission unit accounting details and other reports that the host country will have to submit in accordance with the Article 6.2 guidance. The procedures additionally should describe the expected timing and process by which the program will compare the host country’s reported information on authorization in its national reports with the information provided by country attestations/LoA.
Although the above process puts in place a defined procedure to monitor the application of corresponding adjustments by the host countries until they submit the corresponding Biennial Transparency Report (BTR), TAB, in its August 2024 report, acknowledged that there is a possibility that host countries could alter their corresponding adjustments in BTRs that are submitted in the end year of the NDC implementation period. But as these ‘final’ BTRs are not due until 2032 and will be subject to technical expert review, TAB concluded that any inconsistencies flagged at such a time will be addressed on a case-to-case basis.
For a program to be considered for assessment, it should have been continuously governed for at least the last two years and should have finalized methodologies available for issuances of carbon credits. The criteria clarify that the methodology itself need not to be approved for two years before the program applies, however.
TAB has yet to assess PACM for its eligibility – given its first methodology was only finalized in late 2024 and the first issuance request was approved last week, it is not clear whether it currently meets the assessment criteria. TAB has stated that it will continue to follow PACM’s progress and will undertake its assessment once the program is operational, however.
Programs will have to identify the specific sustainable development contribution or co-benefits that a project will need to adhere to in order to be deemed CORSIA-eligible units. These should be specified by the program as a list or a menu of indicators that the project will have to demonstrate effectiveness against. These criteria could also align with indicators specified by host countries.
Legal or regulatory additionality is now a foundational measure of how additionality is defined by the TAB. TAB allows for demonstration of additionality through either barrier analysis, common practice analysis or performance benchmarks – if a program provides for use of another method to demonstrate additionality, it will have to be explicitly evaluated by the TAB. Previously, a third-party evaluation of such an approach was acceptable by TAB, but this is no longer applicable.
In line with the guidance of Article 6.4 for PACM, programs should require activities to set conservative baselines that are below business-as-usual projections. The program should also require activities to demonstrate how the set baselines are more conservative than the business-as-usual scenario.
The programs are required to have in place procedures that ensure reversal monitoring and full compensation for any material reversal for at least 20 years after the start of the first crediting period. This requirement is increased to at least 40 years for projects where the first crediting period is after December 31 2026. For jurisdictional activities, the program guidelines should ensure that the reversal risk pool is equipped to fully compensate for any reversal risk for the same timeframe.
Where the activity involves replacing equipment that impacts the baseline, the program should ensure that the emissions from the disposal or continued use (in case it is resold or reused elsewhere) of such decommissioned equipment be assessed wherever possible and removed from the verified emissions.
The program’s assigned registry should provide, within 1-3 business days of receiving a retirement request, all identifiable details for the cancellation of CORSIA-eligible emissions units that the operator would require to comply with ICAO’s Standards and Recommended Practices (SARPs). This information should also be made available on the registry’s public-facing website at no cost or credential requirement.