On 6 December 2024, the International Civil Aviation Organization (ICAO) released a series of documents detailing eligibility and exclusion criteria for crediting programs as part of Phase 1 for the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). The update establishes detailed eligibility requirements for carbon credits supplied by six approved registries and introduces stricter exclusions and attestation requirements. These changes significantly impact the Voluntary Carbon Market (VCM), where CORSIA is expected to drive substantial demand for high-integrity credits.
CORSIA, established by ICAO in 2016, is a market-based measure designed to curb international aviation emissions. Under CORSIA, airlines with flights between participating states must offset emissions above a set baseline by purchasing Eligible Emissions Units (EEUs). Further information regarding the scheme can be found in ClearBlue’s CORSIA Primer.
Offsetting under CORSIA began in 2021, and participants under the scheme must demonstrate, upon completing every 3-year compliance period, that they have met their offsetting requirements. Due to the COVID-19 pandemic and its impacts on the aviation industry, there were no compliance obligations for the Pilot Phase. The pandemic also led to 2020 being excluded from baseline calculations, and the current baselines are expected to be reviewed in September 2025.
ICAO’s phases, as well as the current status of crediting programs for CORSIA, are summarized in the following tables:
|
Phase |
Timeline |
Baseline Emissions |
Participation |
|
Pilot Phase |
2021–23 |
2019 |
|
|
First Phase |
2024–26 |
85% of 2019 |
|
|
Second Phase |
2027–35 |
85% of 2019 |
|
Source: CORSIA Summary Table from ICAO
The documents published by ICAO include:
- A detailed Technical Advisory Body (TAB) Recommendations Report
- CORSIA EEUs Summary for the approved crediting programs
- Public Comments on CORSIA Updates
After approving four standards in late October, six crediting programs have been approved so far to provide EEUs for Phase 1 of CORSIA. A summary of the current status of the six programs providing EEUs is shown below:
|
Registry |
Eligibility Period |
Key Exclusions |
Special Exceptions |
Additional Measures |
|
American Carbon Registry (ACR) |
2016 start; reductions 2021–2026 |
California & Washington ROCs; REDD+ >7,000 ERTs/year |
N/A |
Leakage and reversal risk protocols must be met |
|
Architecture for REDD+ Transactions (ART) |
2016 start; reductions 2021–2026 |
REDD+ >7,000 credits/year |
N/A |
Strong jurisdictional frameworks required |
|
Climate Action Reserve (CAR) |
2016 start; reductions 2021–2026 |
Nature-based in non-REDD countries (except Mexico Forest Protocol); REDD+ >7,000 CRTs/year |
Mexico Forest Protocol for certain projects |
Leakage and double-claiming mitigation required |
|
Global Carbon Council (GCC) |
2016 start; reductions 2021–2026 |
Nuclear, HFC-23, afforestation, reforestation (A/R), REDD, CCS |
Buffer deduction applied for all credits |
Requires a 15% buffer pool (C+ credits) |
|
Gold Standard (GS) |
2016 start; reductions 2021–2026 |
Nature-based in non-REDD countries (except soil carbon, agriculture, and livestock methodologies) |
Soil carbon, agriculture, and livestock methodologies allowed |
Shared reversal risk pool required |
|
Verified Carbon Standard (VCS) |
2016 start; reductions 2021–2026 |
Cookstoves (AMS-II.G, VMR0006); REDD+ >7,000 VCUs/year; renewable projects >15 MW |
JNR scenarios (2a, 3); specific forest, soil, and grassland methodologies |
Enhanced leakage/reversal protocols |
The updated CORSIA guidelines significantly constrain supply by excluding project types like large-scale REDD+ credits (>7,000 per year), afforestation/reforestation, and renewable energy projects above 15 MW. These exclusions particularly impact high-volume credits in REDD+ countries and older methodologies like AMS-II.G and VMR0006, further narrowing the pool of eligible credits. Airlines’ growing demand for compliance credits, coupled with competition from voluntary buyers, is expected to push prices higher, with premiums likely for high-integrity credits like jurisdictional REDD+ and soil carbon projects.
Operationally, requirements such as host-country attestation to prevent double-claiming and transitioning to compliant methodologies (e.g., Verra’s VM0050) add complexity, especially for smaller developers in non-Annex I nations. Despite these challenges, the stricter criteria align with the Paris Agreement and emphasize transparency and accountability, positioning CORSIA as a driver of integrity in the carbon market.
The revised CORSIA criteria set a high bar for compliance, pushing the aviation sector toward higher-integrity carbon credits while creating supply bottlenecks. These changes will reshape credit pricing, demand, and supply dynamics in the VCM. For project developers, transitioning methodologies and aligning with ICAO’s rules will be critical.
For detailed insights or support in navigating these updates, please contact our Market Intelligence team.