As known to all and sundry by now, CORSIA stands for Carbon Offsetting and Reduction Scheme for International Aviation.

It is a global market-based mechanism developed by the International Civil Aviation Organization (ICAO). Its primary goal is to achieve carbon-neutral growth for international aviation from 2020 onward, addressing emissions not covered by the Paris Agreement. CORSIA applies to international flights between participating countries and does not cover domestic aviation emissions.

CORSIA is being implemented in phases, which are -

• Pilot Phase (2021–2023): Voluntary participation by States.

• First Phase (2024–2026): Voluntary participation continues.

• Second Phase (2027–2035): Mandatory for all states, except for least-developed countries (LDCs), small island developing states (SIDS), and landlocked developing countries (LLDCs).

Now, India is not part of it, but how can Offsetting projects in India match up to the CORSIA needs? Actually, what kind of offset projects make the cut for CORSIA?

Literature says that CORSIA allows airlines to offset their emissions using CORSIA Eligible Emission Units (CEUs), which are derived from verified carbon offset projects. These projects must adhere to strict quality criteria set by the International Civil Aviation Organization (ICAO).

Now the types of carbon credit projects that are typically approved under CORSIA are the usual ones which I have summarised below. Also, CORSIA specifically encourages the use of SAFs, which must demonstrate lifecycle greenhouse gas reductions compared to conventional jet fuel. Approved SAFs include fuels made from waste biomass, used cooking oil, and agricultural residues, advanced biofuels like Fischer-Tropsch or Hydroprocessed Esters and Fatty Acids (HEFA).

Now, the projects -

• NbS - ARR, REDD+ & Wetland and Peatland Conservation and Restoration

• Renewable energy - While renewable energy is more controversial in voluntary markets today due to additionality concerns, CORSIA considers certain projects if they adhere to rigorous baselines - Solar, wind, and geothermal energy projects, & Small-scale hydropower projects (subject to sustainability criteria).

• Methane Capture and Utilisation - Landfill Gas & Livestock Waste Management

• Energy Efficiency Projects- Mostly Retrofitting or upgrading industrial and residential facilities to reduce energy consumption, & Waste heat recovery systems in industrial operations.

• Industrial Gas Destruction - Projects targeting the destruction of potent greenhouse gases like hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and nitrous oxide (N2O) from industrial processes.

• Waste Management & Circular Economy Projects

Literature also says that the key quality for approval remains the good old Additionality, Permanence, Transparency, No double Counting, Social & Environmental Safeguards and Verification.

To be noted - Eligible credits must come from projects generating emission reductions after January 1, 2016, to ensure alignment with CORSIA’s timeline.

Projects must also follow detailed MRV protocols to track emissions and reductions, CORSIA only accepts credits from offset projects that are verified and issued under standards approved by ICAO < examples - Verra, Gold Standard, CAR, ACR >

While it might seem that there are no extremely different parameters, I am pointing out some striking differences -

1. Baseline for Carbon Neutral Growth - CORSIA sets the baseline for emissions at the average of 2019 and 2020 levels, and airlines must offset emissions above this baseline.

2. CORSIA excludes certain types of projects which are mostly large scale renewable energy projects due to additionality concerns.

3. CORSIA focuses more on high-integrity nature-based solutions (NbS) and emissions avoidance or reduction projects with clear additionality.

4. CORSIA integrates Life-Cycle Emissions Accounting as a mandatory evaluation for Sustainable Aviation Fuels (SAFs). This goes beyond standard VCM projects by requiring that emissions from feedstock cultivation, processing, transportation, and combustion to be fully quantified, and a minimum 10% GHG savings threshold compared to conventional jet fuel.

5. Unlike regular carbon projects, which may calculate leakage broadly, CORSIA has strict rules to quantify and address leakage for land-based projects, particularly those involving REDD+, Peatland and wetland conservation.

6. To manage risks of reversal in carbon storage (due to wildfires or deforestation or any Act of God), CORSIA-approved standards require use of buffer pools and insurance mechanisms.

7. No double counting across NDCs - CORSIA mandates that emission reductions cannot be double-counted toward both a country’s NDC and the airline’s offset obligations. This often requires a "corresponding adjustment" to ensure credits are uniquely accounted for in international frameworks.

8. While VCM projects are usually tailored to regional or sector-specific goals, CORSIA operates under a uniform global framework for the aviation industry.

9. As mentioned before, eligible credits must come from projects generating emission reductions after January 1, 2016, to ensure alignment with CORSIA’s timeline.

10. Unlike VCM, where carbon removal (e.g., direct air capture, biochar) is increasingly dominant, CORSIA emphasizes emission avoidance projects, including REDD+.

11. CORSIA credits are listed in an ICAO-managed Central Registry, ensuring full transparency and traceability. This centralization differs from fragmented registries in voluntary markets, enhancing trust and accountability.

12. CORSIA credits are designed exclusively for the aviation industry and cannot be freely traded or used by other sectors, unlike regular carbon credits.

This brings forth a handful of new trends in the carbon market and potential for more. Thoughts?