Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA): –

is a Global Market Based Measure (GMBM) and the first of its kind for any industry sector.  There is global Monitoring, Reporting and Verification (MRV) system which forms one of a basket of measures being considered by the International Civil Aviation Organization (ICAO) in order to achieve its global aspiration of carbon neutral growth.

Other measures which form the ‘basket of measures’ include:

aircraft technology, operational improvements and sustainable alternative fuels.


Contribution of Measures for Reducing International Aviation Net CO2 Emissions

© ICAO 2017


October 2016 – ICAO’s 39th triannual assembly passed a resolution for a global market based measure ‘CORSIA’. During the baseline years of 2019 and 2020 the average level of CO2 emissions from international aviation will be calculated from commercial aircraft operators submitting an ICAO ‘Form A’ to their UN member state of registration either on a monthly or annual basis.

* Note:

ICAO’s Form A Instructions [PDF]

ICAO’s Form A Template [Excel]  

Our MRV software portal will allow all operators to quickly import their flight data and it will automatically populate a ‘Form A’ for that carrier ready to submit to their UN state.


Information collected during the baseline years will form a basis for carbon neutral growth from 2020 onward.  The emissions calculated in future years will be comparable to this baseline.

Therefore from 2021 and any year thereafter emissions will be monitored, reported and verified and submitted to the UN member state. If the average baseline emissions of 2019 and 2020 are exceeded by those international aviation emissions reported then the difference will represent the sector’s offsetting requirements for that year.


2019-2020 – Baseline reporting years

2021-2023 – Pilot phase (Voluntary phase – Applicable to UN states that have volunteered to participate)

2024-2026 – First Phase (Voluntary phase – Applicable to UN states that have volunteered to participate)

2027-2035 – Second Phase (Mandatory phase – Applicable to all UN states that have an individual share of international aviation activities in Revenue Tonne-Kilometres (RTKs) in year 2018 above 0.5 percent of total RTKs)

Some UN states are exempt from the scheme unless they have volunteered to participate. These are:

Least Developed Countries (LDCs), Small Island Developing States (SIDS) and Landlocked Developing Countries (LLDCs).

* Note:

A list of these can be found here http://www.unohrlls.org/


September 2017 – Global Market based measure Technical task Force (GMTF) which has been assigned by ICAO’s Committee on Aviation Environmental Protection (CAEP) is expected to produce a final draft of the Standards and recommended Practices (SARP’s) and associated guidance notes

October – December 2017 – Following an approval at the 212th ICAO council meetings the CORSIA guidance will be published for circulation

End of 2018 – Final review and approval of CORSIA SARPs

January 2019 – Implementation of Baseline years.

As of the 27th August 2017, 72 UN states intend to voluntarily participate in CORSIA, representing 87.7% of international aviation activity.

* Note:

A list of these can be found here https://www.icao.int/environmental-protection/Pages/market-based-measures.aspx


Who’s Affected and What’s Covered

All international flights and all international commercial aircraft operators are affected including airlines, commercial business aviation, air taxis and other on-demand services.

  • International flights between two UN states where both states opted into the scheme voluntarily are affected by the National regulations under CORSIA
  • International flights between two UN states where only one state opted into the scheme voluntarily are exempt however the flight still needs to be reported to the national authority.
  • International flights between two UN states where both states did not opt into the scheme voluntarily are exempt.


The voluntary application is only applicable from 2021 to 2026.

The regulation will become mandatory for all states by 2027.


* Note:

Our MRV software automatically distinguishes between UN states and automatically produces Verified Annual Emission Reports for those international flights ready to submit to the national authorities.


Route Based Approach in CORSIA


  • Aircraft operators emitting less than 10,000 metric tonnes of CO2 emissions from international aviation per year.
  • Aircraft with Maximum Take-Off Mass (MTOM) less than 5,700 kgs
  • Humanitarian, medical and firefighting operations


Baselines and Offsetting requirements

The calculation of emissions from any given year ‘y’ will be compared to the baseline average from 2019 & 2020. The difference will provide the offsetting total required.

Sector Wide Offsetting Requirements


Monitoring, Reporting, Verification (MRV) Procedures


1st January 2019 – All aircraft operators are advised that the implementation of MRV is a mandatory requirement for all international flights.

In order to calculate the sector growth factor and offsetting requirement from the year 2021 and onward, an annual MRV is required to collect the CO2 emissions to form baseline data for the years of 2019 and 2020 from international aviation operations.

* Note:

ICAO’s Form A Instructions [PDF]

ICAO’s Form A Template [Excel]  

Our MRV software portal will allow all operators to quickly import their flight data and it will automatically populate a ‘Form A’ for that carrier ready to submit to their UN state.


  • Following a fuel monitoring method the fuel burn and CO2 emissions are calculated on each flight. This is based on 1 tonne of fuel burnt to produce 3.16 tonnes of CO2. (emissions factor 3.16)
  • Accredited verifiers are used to verify the data is correct therefore meeting compliance obligations.
  • The calculated fuel burn and emissions are reported using an Annual Emissions Report (AER) which is in turn verified by an accredited verifier and submitted to the UN state authority. The data is then submitted to the ICAO to consolidate and publish the total number of CO2 emissions emitted and the annual sector growth factor.

Overview – MRV Flow Diagram

Carbon Emission Offset Credits


Aircraft operators will have to purchase carbon offset credits for those emissions calculated over the average baseline data from 2019 and 2020.

Projects around the world that generate carbon offset credits must meet an Emission Unit Criteria (EUC) which must include:

  • Clear methodologies and protocols and their development process
  • Scope considerations
  • Offset credit issuance and retirement procedures
  • Identification and tracking
  • Legal nature and transfer of units
  • Validation and verification procedures
  • Program governance
  • Transparency and public participation provisions
  • Safeguarding systems to address environmental and social risks
  • Sustainable development criteria
  • Avoidance of double counting, issuance and claiming


Further to the above requirements the offsetting programs should deliver credits that they:

  • Are additional
  • Are based on a realistic and credible baseline
  • Are quantified, monitored, reported and verified
  • Have a clear transparent chain of custody
  • Represent permanent emission reductions
  • Assess and mitigate against potential increase in emissions elsewhere
  • Are only counted once towards a mitigation obligation
  • Do no net harm



CORSIA Registries


To be able to securely monitor credit activity a central repository has to be established in the form of an ICAO consolidated central registry.  Member states, groups of states, will have to independently establish their own registry or participate in other state registries.  The information held in the registry will be of the following nature:

  • Purchase of emission units
  • Ownership and transfer of emission units from one account to another
  • Surrender of emission units towards offsetting requirements
  • Track operators compliance with offsetting requirements


Work in Progress

CORSIA is work in progress and the development of the global market based measure is evolving. However as we get closer to a working product there remains questions surrounding the development and how best to deal with certain aspects. Some of these questions that still remain unanswered are:

  • Double Counting / Claiming:

CORSIA intends to offset emissions against projects around the world which produce carbon credits.  However Emission Reductions (ERs) produced by a project would reflect against the country’s Intended Nationally Determined Contributions (INDCs) where the project is implemented.  Airline operators offsetting their emissions on the same project under CORSIA would lead to a double counting scenario and the claiming of the same ER.


  • ITMOs: The expected process for the transfer of ERs between countries meeting their compliance obligations is International Transferred Mitigation Outcomes (ITMOs) under Article 6 of the Paris agreement. If CORSIA is to use the same ITMOs procedure then it would need to be setup as a country in terms of creating an accounting process for the net purchase of ERs. However a solution is required if the ITMOs are transferred from an ER project to an aircraft operator under CORSIA who all reside in the same country.


* Note:

More information about CORSIA will be available as the development progresses.  Our team are on hand to answer any questions surrounding the new GMBM and our MRV software portal is ready to help calculate your emissions.