The Air Navigation (Carbon Offsetting and Reduction Scheme for International Aviation) Order 2021

Jurisdiction: UK

Commencement: 26th May 2021

Amends: New Legislation

Mini Summary

This Order implements the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) in the UK and contains duties for aeroplane operators, verification bodies and Regulators in the UK.


The International Civil Aviation Organisation (ICAO) adopted the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) in 2016 to address CO2 emissions from international aviation.

The aim of CORSIA is to stabilise net COemissions from international aviation at 2020 levels, by complimenting emissions reduction initiatives with carbon offsetting (i.e. where an organisation or individual compensates for their emissions by financing a reduction in emissions elsewhere).

It is forecast that CORSIA will mitigate 2.5 billion tonnes of CO2 between 2021-2035.


CORSIA only applies to international flights (flights that take off and land in different states), not domestic flights.

As CORSIA only applies to civil aviation, state flights are excluded from CORSIA. This includes military, customs, and police flights. Humanitarian, medical, and firefighting operations are also exempt.

Operators of aeroplanes with a maximum takeoff mass of 5700 kg or less are exempt.

Operators that begin operating international flights after 2019 are exempt from the offsetting requirements for a 3 year grace period. To be considered a ‘new entrant’ the  operator must be in no way associated with any other company operating international flights e.g have a parent company or resulting from the takeover of international flights of another company.


The international standards for the implementation of CORSIA must be applied by all of the ICAO’s member states.

Reporting of emissions

Operators with annual emissions over 10,000 tonnes of CO2 are required to annually report their emissions from 1st January 2019, for international flights only.

In order to do this, operators must track fuel use of individual flights using 1 of the 5 approved fuel use monitoring methods. In certain circumstances operators may be eligible to use simplified monitoring and estimate emissions using the CERT, an ICAO estimation tool.

Operators must develop an emissions monitoring plan which includes information on the operator, its fleet, and operations, detailing the methods used to monitor fuel use, calculate emissions, and associated data management. It must then be submitted to the national authority for approval.

Annual emissions reports must be verified by an independent third party verification body (accredited to ISO 14065 and meeting CORSIA specific requirements) prior to submission to member states. The emissions monitoring plan will help the verifier to check that the approved methods have been applied correctly by the operator during verification.

The member state will then report the aggregated emissions to the ICAO, which will then publish the total emissions reports.

Offsetting requirements

From 2021, at the end of each 3 year compliance period, operators must demonstrate that they have met their offsetting requirements by cancelling the appropriate number of emissions units.

Administering authorities will notify operators of their final offsetting requirements by the 30th November following the end of a 3 year compliance period, with provisional offsetting requirements provided by the 30th November on an annual basis.

CORSIA phases

There will be a phased approach to the introduction of carbon offsetting into CORSIA with the following phases decided:

  • 2019 – 2020 – Monitoring, reporting and verification (sets the baseline, no offsetting requirements).
  • 2021 – 2023 – Pilot phase (voluntary offsetting requirements).
  • 2024 – 2026 – First phase (voluntary offsetting requirements).
  • 2027 – 2035 – Second phase (mandatory offsetting requirements).

From 2021 – 2026 only flights between states that have volunteered to participate will be subject to offsetting requirements.

n.b operators based in an exempt state will still be required to offset and flights between volunteering states.

After this, from 2027 all international flights will be subject to offsetting requirements; however, flights to and from the following states will be exempt, unless the state participates on a voluntary basis:

  • Least Developed Countries (LDCs);
  • Small Island Developing States (SIDS);
  • Landlocked Developing Countries (LLDCs); and
  • states which represent less than 0.5% of international aviation activities.

Cancelation of emissions units

Operators must cancel the required number of units by the 31st January following notification of the final offsetting requirements. Operators may cancel units prior to notification if they wish.

Information on the emissions units cancelled must be compiled into an emissions cancellation report which, once verified, is submitted to the administering authority.

When an emissions unit is cancelled it is taken out of circulation and becomes unavailable for any other uses.

Determination of offsetting requirements

An operator’s offsetting requirements are determined by its administering authority; however, final offsetting requirements will benefit from a reduction where an operator has used CORSIA eligible fuels*.

The emissions reductions will be proportional to the life cycle emissions benefits of the fuel used compared to jet fuel.

*CORSIA eligible fuels are those which meet the sustainability criteria; fuel must achieve net emission reductions of at least 10% compared to conventional jet fuel on a life cycle basis (i.e. all emissions from the full supply chain for production and used, as well as emissions from induced land-use change). They must also not be made from biomass obtained from land with high carbon stocks.

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