Guidance

CORSIA: how to comply

Guidance to help UK administered aeroplane operators comply with the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA).

From:
Environment Agency
Published
7 June 2021
Last updated
12 April 2024 — See all updates

About this guidance

You will need to comply with CORSIA as soon as you become an aeroplane operator.

This guidance will help aeroplane operators understand and comply with their obligations under CORSIA. These obligations are set out in full in The Air Navigation (Carbon Offsetting and Reduction Scheme for International Aviation) Order 2021 (the air navigation order). A further air navigation order will set out the offsetting obligations.

If you need to comply with CORSIA, you must:

  • monitor and record your CO2 emissions from international flights for each scheme year, which runs from 1 January to 31 December

  • report your verified emissions from international flights by 30 April in the following year

From 2025 and then every 3 years, purchase and cancel eligible emission units equal to your final offsetting obligation. Your final offsetting obligation will be based on your emissions from international flights subject to offsetting requirements, as notified by your regulator.

If you do not comply with a CORSIA requirement you may have to pay a civil penalty.

If you are not sure about your obligations, or any aspect of this guidance, please contact your regulator.

If you are (or expect to be) an aircraft operator under the United Kingdom Emissions Trading Scheme (UK ETS), you can find out what you need to do to comply with that scheme in the guidance UK ETS for aviation: how to comply.

About CORSIA

CORSIA is the International Civil Aviation Organization’s (ICAO) global market-based measure for international aviation emissions. CORSIA consists of the following 3 phases, which are divided into 3-year compliance periods:

  • pilot phase (2021 to 2023)

  • first phase (2024 to 2026)

  • second phase (2027 to 2029, 2030 to 2032, and 2033 to 2035)

CORSIA requires aeroplane operators to offset the growth in international aviation emissions above a baseline. There was a baseline monitoring period during 2019 and 2020. In June 2020 the ICAO Council agreed that the baseline during the pilot phase will be 2019 emissions levels only, to take into account the significant reduction in air traffic and emissions in 2020 due to the coronavirus (COVID-19) pandemic. In October 2022, the 41st ICAO Assembly agreed that the baseline for the first phase onwards will be 85% of 2019 emissions levels.

State participation in the pilot phase and the first phase is voluntary. The UK confirmed to ICAO in June 2020 that it will participate in CORSIA from the start of the pilot phase. The second phase will include all ICAO states, except those subject to exemptions.

Emissions from international flights operated between participating states will be subject to offsetting. ICAO lists the Chapter 3 state pairs that participate in CORSIA.

ICAO will review CORSIA every 3 years.

You can find out more about CORSIA from ICAO.

More CORSIA guidance

This guide provides a summary overview of compliance tasks and deadlines as set out in the air navigation order. You can find more information on how to meet your obligations in the following ICAO pages:

Work out if CORSIA applies to you

You will need to work out whether:

  • you are an aeroplane operator under CORSIA

  • international flights are attributed to you

  • the UK is your administering state

Aeroplane operator

You are an aeroplane operator if your annual CO2 emissions from international flights using aeroplanes with a maximum certificated take-off mass greater than 5,700 kilograms exceed 10,000 tonnes.

International flights

An international flight is the operation of an aircraft from take-off at an aerodrome of a state or its territories, to landing at an aerodrome of another state or its territories. CORSIA does not apply to the following flights, and you do not need to include them when assessing whether you are an aeroplane operator:

  • humanitarian, medical and firefighting flights

  • international flights before or after a humanitarian, medical or firefighting flight – provided they are carried out by the same aeroplane and are either needed for these activities, or to reposition the aeroplane for its next activity

  • flights by state aircraft (aircraft used in the military, customs or police services)

If you are not sure whether your flights should be included, please contact your regulator.

Attributing a flight to an aeroplane operator

Under CORSIA, you will need to monitor and report your CO2 emissions on international flights (other than humanitarian, medical and firefighting flights) attributed to you for every scheme year. International flights are attributed to you if:

  • item 7 of the flight plan contains your ICAO designator, and if not

  • item 7 of the flight plan contains the nationality or common mark, and registration mark of an aeroplane listed in your valid aircraft operator certificate (AOC) (or equivalent)

Where item 7 of the flight plan does not contain this identifying information, the flight will be attributed to the aeroplane owner, unless they can provide information to identify the actual operator of the flight.

Two or more consecutive flights operated under the same flight number are considered to be separate flights.

How to work out if the UK is your administering state

An aeroplane operator is administered by the UK under CORSIA if:

  • it has an ICAO designator which identifies the UK as the ‘notifying state’, and if not

  • it has a valid AOC (or equivalent) issued by the UK Civil Aviation Authority, and if not

  • it either has its registered office in the UK, or is an individual resident there

If a change in circumstances results in a change to your administering state, you would be transferred to the new administering state from the start of the next compliance period.

If you are a UK administered aeroplane operator with a wholly owned subsidiary aeroplane operator with a registered office in the UK, you may seek approval from your regulator, to be treated as a single consolidated aeroplane operator for compliance with CORSIA.

CORSIA regulators

There are 4 regulators in the UK for aeroplane operators regulated under CORSIA. You are assigned a regulator based on the location of your registered office or place of residence. For:

You must notify your regulator within 3 months if you change the location of your registered office, or place of residence.

If you think you may be an UK administered aeroplane operator with obligations under CORSIA, you must contact your regulator as soon as possible.

When you contact your regulator, you will need to provide the aeroplane operator name (full name of the legal entity, or individual).

You will also need to provide the following details for your primary contact responsible for CORSIA compliance:

  • first name and surname

  • telephone number

  • email address

Your METS online account

Once you have provided the information your regulator needs, they will set up your account in the ‘Manage your UK Emissions Trading Scheme reporting’ service (known as METS). When this is done, METS will provide you with login instructions.

Your regulator manages applications, variations and report submissions through METS.

METS:

  • allows you to send notifications to and receive them from your regulator

  • sends you reminders of actions you must or may need to take

  • allows you to submit your annual emissions report, and your verification report

  • allows you to submit your improvement report (if required)

  • allows you to submit your verified emissions unit cancellation report

  • allows you to make applications to modify (change) your emissions monitoring plan

The forms in METS are designed to help aeroplane operators provide the required information. They include guidance on how to complete specific fields within the forms. Where available, the forms also provide references to additional guidance documents or legislation.

Apply for an emissions monitoring plan

If you do need to apply for an emissions monitoring plan, access your account in METS using the login details provided by your regulator. The task to complete your emissions monitoring plan application will appear in your work queue. You must use the online form to complete and submit your emissions monitoring plan. There is guidance in the form to help you provide the right information.

You must submit an emissions monitoring plan application within 3 months of becoming an aeroplane operator. If you cannot meet or have missed this deadline, you must contact your regulator.

New entrant

A new entrant is any aeroplane operator that commenced an aviation activity falling within the scope of the air navigation order on or after its entry into force 26 May 2021. As a new entrant, you must monitor and record your fuel use, and report emissions from international flights from the scheme year after becoming an aeroplane operator. Different rules will also apply to your offsetting obligations. If you are a new entrant, your regulator will help you understand your obligations.

Eligible monitoring methods

The amount of annual emissions from your international flights with offsetting obligations will affect which monitoring method you can use. International flights with offsetting obligations are flights between Chapter 3 state pairs.

An aeroplane operator with annual CO2 emissions from international flights between Chapter 3 state pairs of greater than or equal to 50,000 tonnes, must use a fuel use monitoring method described in Schedule 2 of the air navigation order for these flights. For its other international flights (not between Chapter 3 state pairs), the aeroplane operator may use either:

An aeroplane operator, with annual CO2 emissions from international flights between Chapter 3 state pairs of less than 50,000 tonnes, may use either a Schedule 2 fuel monitoring method or the CERT.

Whichever method or methods you choose, you must set these out in your emissions monitoring plan. And where you do not exceed or drop below the annual 50,000 CO2 threshold during a compliance period, you must use the same method for the entire compliance period.

You can find more detailed guidance about the information required in an emissions monitoring plan in the Environmental Technical Manual (Doc 9501).

Submitting applications to your regulator

You must submit any application to your regulator:

  • through METS – this will ensure you provide the information needed

  • with payment for any fee required

Any application you submit to your regulator is not ‘duly made’ until you have:

  • provided all the information required

  • submitted the application form

  • paid any fee required

You can find the fees for each CORSIA regulator on their website:

Your regulator must usually ‘determine’ an application within 2 months of the date it was duly made, unless you agree to a longer period.

After submitting your application

Once you have submitted your application, METS tells you about the application fee and how to pay.

Your regulator will assess your application and contact you if they need more information.

Issue your emissions monitoring plan

Once your regulator has approved your application, they will issue your emissions monitoring plan. It details how you must monitor and report emissions from your international flights in line with the requirements of the air navigation order. You must comply with the conditions of your emissions monitoring plan.

It is important that you read and understand your emissions monitoring plan. The introductory note and conditions will help you comply with CORSIA requirements.

Changes to your emissions monitoring plan

You must tell your regulator about any non-significant changes to your emissions monitoring plan through METS.

Some changes to your emissions monitoring plan are regarded as significant and will require you to modify your emissions monitoring plan. To make these modifications you must apply to your regulator through METS. See also the section on making changes.

Complete your compliance tasks

You must complete your CORSIA compliance obligations by any deadlines specified in the air navigation order or your emissions monitoring plan. If you do not, you may have to pay a civil penalty.

Not an aeroplane operator in a scheme year

If you are not an aeroplane operator during a scheme year, then you will have no monitoring, reporting or offsetting obligations for that scheme year.

Your regulator will change the status of your reporting requirements in your METS account to ‘exempt’ if:

  • you inform your regulator that you are not an aeroplane operator during a scheme year

  • your regulator identifies this using independent data

If you think that the change to your account status is incorrect, you must tell your regulator as soon as possible.

Annual monitoring and reporting tasks and compliance deadlines

  • 1 January – start monitoring your international flights for the current scheme year

  • 30 April – submit your verified annual emissions report for the previous scheme year using METS

  • 30 June – submit an improvement report (if applicable)

  • July – start the process of  appointing your verifier for the current scheme year

  • 31 December – notify your regulator of any non-significant changes to your emissions monitoring plan

  • 31 December – complete your monitoring for that scheme year

Offsetting tasks and compliance deadlines

  • 30 November – your regulator will notify you what your offsetting obligation for the previous scheme year is

  • 30 November (from 2024 and then every 3 years) your regulator will notify you what your final offsetting obligation for the previous 3-year compliance period is

  • 31 January (from 2025 and then every 3 years) – offset your emissions from international flights with offsetting obligations for the previous compliance period in line with the figure notified by your regulator

  • 7 February – (from 2025 and then every 3 years) – request that the eligible emissions units programme registry (or registries) communicates your cancellation information on a public website(s)

  • 30 April (from 2025 and then every 3 years) – submit your verified, emissions unit cancellation report for the previous compliance period using METS

Monitor your emissions

You must monitor your international flights from 1 January to 31 December for each scheme year in which you are an aeroplane operator.

Your monitoring requirements are set out in your approved emissions monitoring plan (including any supporting written procedures).

You will use the data collected during monitoring to calculate your emissions and produce your verified annual emissions report. You must submit this report by 30 April in the following scheme year.

Prepare your annual emissions report

You should start to prepare for the reporting process during the final quarter of the scheme year. You must submit your report by 30 April in the following year.

Preparing early should:

  • give you enough time to choose and appoint an independent verifier

  • allow your verifier enough time to carry out the verification

  • enable you and your verifier to address any errors or misstatements

  • submit your report and verification report to your regulator by the 30 April deadline

The task to compile your annual emissions report will appear in your METS work queue on 1 January the following year. This task contains the emissions report form.

The emissions report form will specify the rounding requirements to use for all variables when calculating and reporting emissions.

CORSIA eligible fuels

A CORSIA eligible fuel is a sustainable aviation fuel or a CORSIA lower carbon aviation fuel, which an aeroplane operator may use to reduce their offsetting requirements.

You can only claim a reduction in your offsetting requirements using a CORSIA eligible fuel that both:

  • meets CORSIA sustainability criteria

  • was produced by a fuel producer certified by a CORSIA approved sustainable certification scheme

Any claim for an offsetting reduction from a CORSIA eligible fuel must be made using the ICAO template found by following the link provided in the emissions report form in METS. The completed ICAO template must be uploaded into this METS form.

Record keeping and audits

Your regulator must perform order of magnitude checks on annual emissions reports and may also carry out periodic audits. You must keep records of all relevant data and information for at least 10 years. For example, you must keep the information used to compile a report for 10 years from the date you submitted it to your regulator.

You should keep records relevant to your CO2 emissions by state pair for 2019. This is so you can cross-check your offsetting requirements your regulator has calculated during the 2033 to 2035 compliance period.

Appointing an independent verifier

You must appoint an independent CORSIA accredited verifier to verify your emissions from international flights.

You must give your verifier all the information needed to perform the verification. Your verifier will be able to explain what is needed.

When verifying your annual emissions report, your verifier will assess your:

  • monitoring methods

  • information, data and calculations

  • internal procedures and systems

They are checking to make sure that:

  • you have complied with your emissions monitoring plan and the requirements of the air navigation order

  • the data in your annual emissions report accurately represents what you are required to monitor

To help make sure you are ready to report your emissions by 30 April, you should appoint a verifier by July in the scheme year. This means your verifier can start the verification process as soon as possible. They can start to check the data you will need for compliance from the first 6 to 9 months of the scheme year. This avoids a heavy workload in January or February the following year and possible delays in completing the verification process.

METS contains a list of CORSIA accredited verifiers that have accounts in METS, but you may use any CORSIA accredited verifier. The complete list of CORSIA accredited verifiers can be found at the ICAO CORSIA Central Registry in the document ‘CORSIA Central Registry: Information and Data for Transparency’.

If you are using a verifier that already has an account in METS, you can assign them to your METS account under the ‘Users and contacts’ section and from the ‘Select verification body’ drop-down list. If you are using a verifier that does not have an account in METS, please notify your regulator so they can be added to the system and you can assign them to your account.

Site visits by your appointed verifier

The Environmental Technical Manual (Doc 9501) specifies that the verification body shall conduct a site visit if their risk assessment and evidence-gathering plan requires a site visit to reduce the verification risk to an acceptable level. Site visits can only be waived upon approval by the regulator. The verification body should co-ordinate with the regulator before replacing the required site visit with a remote verification approach.

Submit your verified annual emissions report

By 30 April, you must submit your verified annual emissions report for the previous scheme year to your regulator using METS.

Your independent verifier must also submit their verification report containing their ‘verification opinion statement’ to you using METS by 30 April.

Both the annual emissions report and the verification report must meet the requirements of the air navigation order.

You need to follow these steps to submit your annual emissions report to your regulator.

  1. Complete the annual emissions report in METS.

  2. You must then submit your annual emissions report to your chosen verifier for verification.

  3. Once the verification process is complete, your verifier will return the verified annual emissions report and their verification report to you using METS.

  4. You must then submit your annual emissions report and the verification report to your regulator using METS. If you need to amend the emissions report after it has been verified, you will need to re-submit it to your verifier for re-verification before submitting it to your regulator.

Your report is not formally submitted until you have completed step 4.

METS will provide you with step-by-step guidance to help you complete and submit your emissions report.

If you do not submit a verified annual emissions report by 30 April that meets all the requirements of the air navigation order, you may receive a civil penalty.

Submit your verified emissions unit cancellation report

If you had offsetting obligations in a compliance period, you must submit a verified emissions unit cancellation report by 30 April 2025 and then every 3 years. You must appoint an independent accredited verifier to verify your emissions unit cancellation report.

You must submit your verified emissions unit cancellation report using the form in METS.

If you need to amend the verified emissions unit cancellation report (or the verification report) you must re-submit it to your independent verifier for re-verification.

Civil penalties

You may receive a civil penalty if you fail to comply with your CORSIA obligations. We impose penalties in accordance with the approach set out in our enforcement and sanctions policy.

Improvement reports

You must submit a ‘verifier recommended improvement report’ if your verification report:

  • recommends improvements

  • identifies non-conformities with your emissions monitoring plan

METS will automatically generate an improvement report task if this is the case.

You must submit your improvement report by 30 June in the year you submitted your annual emissions report.

The improvement report must describe how and when you will:

  • address the non-conformities

  • implement the recommended improvements

It may be necessary for you to modify your emissions monitoring plan to address the findings in the improvement report.

If you think the recommended improvements would not improve the monitoring methodology, or would be unreasonably expensive, you must explain why and provide supporting evidence in your improvement report.

Making changes

This section explains when you need to apply to modify your emissions monitoring plan because of changes you have made or are going to make to your aviation operation, and the steps you need to take.

You should regularly check your emissions monitoring plan to:

  • make sure it reflects the nature of your aviation operation

  • assess whether you can improve the monitoring methodology

You should also regularly review your internal risk assessment processes to check whether:

  • the risks that you initially identified have changed

  • the control measures you have put in place are still effective

If you are intending to make one of the following significant or material changes, you must apply to modify your emissions monitoring plan to your regulator in METS. You must do this at least 14 days before you make the change or, where this is not practicable, as soon as possible afterwards. The changes are:

  • changing the emission factor values

  • changing between the calculation methods referred to in Schedule 2 of the air navigation order

  • introducing a new standard fuel type

  • changing the status of the aeroplane operator related to one of the thresholds in article 5 or 22(7) to (12) of the air navigation order

  • changing your parent-subsidiary relationship where you are to be considered a single aeroplane operator for the purposes of the air navigation order

Other changes that require a modification to your emissions monitoring plan are:

  • changing the availability of your data, due to the use of new types of measuring instrument, sampling methods or analysis methods, or other reasons, which leads to higher accuracy in the determination of emissions

  • you have found that data resulting from the previously applied monitoring methodology is incorrect

  • you have to respond to suggestions contained in a verification report to improve your emissions monitoring plan

  • the emissions monitoring plan does not meet the requirements of the air navigation order and your regulator asks you to change it

Changes that are not material, but would affect our regulatory oversight and where you should inform your regulator either before, or within 14 days of making any change are:

  • changing to the name of the aeroplane operator

  • changes to your registered or contact address

Material changes that would require your emissions monitoring plan to be modified are explained in more detail in the Environmental Technical Manual (Doc 9501).

In your application to modify your emissions monitoring plan, you must:

  • describe the proposed change

  • explain whether and how the change affects the information in the emissions monitoring plan

You may need to pay a fee for making a significant or material change.

When notifying non-significant changes to your emissions monitoring plan, you must:

  • describe the change

  • set out (if appropriate) how it affects the information in your emissions monitoring plan

You can monitor and report using the proposed modified emissions monitoring plan before it is approved by your regulator if:

  • the proposed change is not significant

  • following your current emissions monitoring plan would lead to incomplete emissions data

If you are concerned that following your current emissions monitoring plan would lead to incomplete emissions data, you must monitor and report based on both:

  • your current emissions monitoring plan

  • an emissions monitoring plan containing the proposed variations

You must document all your emissions monitoring until your regulator has approved the proposed modification to your emissions monitoring plan.

Offsetting obligations

A further air navigation order will set out the offsetting obligation from 2025 that will be consistent with the Standards and Recommended Practices (SARPs), Annex 16 Volume IV. Your regulator will calculate any offsetting obligation that you may have using both:

Your regulator will notify you of:

  • your offsetting obligation for a scheme year by 30 November in the following year

  • your total final offsetting requirements for each compliance period by 30 November in the year following the end of the compliance period

The final offsetting requirements will take in to account any CORSIA eligible fuel claims made during the compliance period.

Offsetting obligations do not apply to a new entrant for 3 years starting in the year it became an aeroplane operator, or until its annual CO2 emissions exceed 0.1% of the total CO2 emissions from international flights in 2019, whichever occurs earlier.

Eligible emissions units

Offsetting involves purchasing and then cancelling eligible emission units equal to your final offsetting obligation in a programme registry (or registries) approved by ICAO by 31 January 2025 and then every 3 years.

Find out more about eligible emissions units and programme registries.

It is your responsibility to request the programme registry (or registries) communicates the relevant unit cancellation information on a public website. You must do this by 7 February 2025, and then every 3 years.

Unhappy with a decision

If you are unhappy with a decision your regulator has made, please discuss it with them first. Where you have a right of appeal against the regulator’s decision, this will be set out in the notice containing the decision. The notice will also provide information about how to appeal.

In the case of an appeal against a decision of:

  • the Scottish Environment Protection Agency – the appeal body is the Scottish Land Court

  • the Chief Inspector (Northern Ireland) – the appeal body is the Planning Appeals Commission

  • all other regulators – the appeal body is the first-tier tribunal

If you are unhappy with the performance or any decision of your verifier, please discuss it with them first. If having discussed your concerns with your verifier you are still not satisfied, you should contact their accreditation body and also inform your regulator.

You can find a list of CORSIA accredited verifiers and their respective national accreditation bodies at the ICAO CORSIA Central Registry in the document ‘CORSIA Central Registry: Information and Data for Transparency’.

Updates to this page

Published 7 June 2021
Last updated 12 April 2024 + show all updates

  1. Updated the guidance to reflect the introduction of a new online system (METS) and processes to replace ETSWAP. Included guidance for offsetting and CORSIA eligible fuels.

  2. First published.

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