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COVID-19 impacts and 2022 CORSIA periodic review

The COVID-19 pandemic has posed unprecedented challenges to the world, including the international air transport sector. This web page aims to provide up-to-date information on various impacts of the ongoing situation on the implementation of the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), as well as the remedial measures and decisions being taken by ICAO.

Impact of COVID-19 on CORSIA implementation in 2020

2020 CORSIA reporting timelines

CORSIA implementation is undertaken as per the Standards and Recommended Practices (SARPs) contained in Annex 16, Volume IV, the First Edition of which became applicable on 1 January 2019. Appendix 1 of Annex 16, Volume IV includes timelines for the 2020 reporting of CO2 emissions from international aviation activity in 2019, namely:

  • 31 May 2020 for an aeroplane operator and a verification body to submit the Emissions Report for the operator’s 2019 CO2 emissions, together with the associated Verification Report. Both reports are to be submitted to the State to which the aeroplane operator is attributed.
  • 31 August 2020 for a State to submit to ICAO, through the CORSIA Central Registry (CCR), the State’s Emissions Report for the aggregated 2019 CO2 emissions of the aeroplane operators attributed to the State, based on the operators' verified Emissions Reports.

Identified challenges for verification and site visit

Since the outset of the COVID-19 pandemic, several States and aeroplane operators alike have expressed concerns regarding their capacity to meet the 2020 CORSIA reporting timelines above. A frequent cause of the concern is the difficulty to conduct the verification of the aeroplane operators’ Emissions Reports, due to the fact that mobility restrictions pose a challenge to the organization of verification bodies’ site visits to the operators’ facilities.


In the context of the verification of aeroplane operators’ Emissions Reports, site visits are not a requirement as per the SARPs in Annex 16, Volume IV, although they are recommended in the guidance provided in the Second Edition of the Environmental Technical Manual (Doc 9501), Volume IV.


ETM, Volume IV describes the site visit as an essential part of the verification activities, in order for the verification body to collect sufficient and appropriate evidence to confirm whether the Emissions Report is free from material misstatements and material non-conformities. The decision to undertake a site visit as part of the verification of the aeroplane operator’s Emissions Report is to be taken by the verification body on the basis of a risk analysis during the preparatory stage of the verification.

Alternative approach (e.g. remote verification) with risk analysis and coordination

ETM, Volume IV provides additional information on the procedure to be followed in the event of a verification body’s decision to not conduct site visits in the context of the verification of an aeroplane operator’s Emissions Report:


If the verification body decides to replace a site visit(s) with other means, this has to be clearly indicated in the Verification Report. This includes the reasoning for the decision on the basis of the risk analysis as well as a detailed explanation of the technical systems used. The verification body should coordinate with the State of the aeroplane operator before replacing the site visit with an alternative approach.

— ETM, Volume IV,


In line with this, several States may need to consider flexibility to replace a site visit with remote verification techniques as part of the verification process, in coordination with their national accreditation bodies, aeroplane operators and verification bodies. Some States are already taking steps to provide a certain degree of flexibility to their operators regarding the date of submission of the verified Emissions Reports, while at the same time still considering 31 August 2020 as a plausible date for the submission of aggregated information from States to ICAO.

ICAO response

Mindful of the concerns from States and aeroplane operators in terms of their capacity to meet the 2020 CORSIA reporting requirements and timelines in light of the COVID-19 pandemic, ICAO adjusted the planned CORSIA capacity building activities, including the deployment of additional activities, to allow for a continuous support to States.


Thus far, the following activities have been undertaken:

The ICAO Council, at its 220th Session (June 2020), recognized the various measures taken by the Secretariat during the COVID-19 pandemic, to ensure the continued support to States for CORSIA implementation. The Council encouraged States to make all the efforts to meet the deadline of 31 August 2020 to report on their respective CO2 emissions data corresponding to year 2019, as per the timeline reflected in Annex 16, Volume IV, Appendix 1.

At the same time, the Council, cognizant of the challenges posed by the current situation, invited those States that have difficulty in meeting this deadline of 31 August 2020 to inform the Secretariat (for example, by communicating through email, sending a letter, or filing a difference to the relevant provisions in Annex 16, Volume IV under Article 38 of the Convention on International Civil Aviation). The Council also requested the Secretariat to work flexibly to accommodate late submissions by States, as appropriate.


Impact of COVID-19 on CORSIA design

Identified issues

While more information is needed to accurately quantify the impact of the COVID-19 pandemic on the aviation sector's CO2 emissions in 2020 and subsequent years, this impact has resulted so far in a sharp decline in aviation activity, with an expected related decrease in the sector's CO2 emissions in 2020, compared to the forecasted 2020 CO2 emissions prior to the pandemic.


CORSIA's sectoral baseline is defined as the average of total CO2 emissions for the years 2019 and 2020 on the routes covered by CORSIA offsetting in a given year from 2021 onwards (Assembly Resolution A40-19, paragraph 11). Therefore, the expected reduction of the 2020 CO2 emissions from international aviation due to the COVID-19 pandemic will lead to a decrease of the CORSIA baseline, compared to the non-COVID-19 scenario.


It is important to note that the COVID-19 pandemic is expected to affect not only the global aviation sector's 2020 activity, but also that of subsequent years. The impact on the sector's CO2 emissions in years to come is being assessed by the development of possible recovery scenarios from 2021 onwards, which are subject to a high level of uncertainty.


The impact of the COVID-19 pandemic on the CO2 emissions from international aviation in 2020 and subsequent years could affect the following three CORSIA's design features, defined in Assembly Resolution A40-19, as follows:

  • CORSIA calculates annual offsetting requirements for individual aeroplane operators every year from 2022 based on an annualSector's Growth Factor (SGF), which represents the CO2 emissions growth of international aviation in a given year from 2021, compared to CORSIA's sectoral baseline (average of 2019 and 2020). The impact of COVID-19 on a given year's SGF will be reflected through: the impact on CORSIA's sectoral baseline; and the impact on the given year's CO2 emissions from international aviation, which will depend on the aviation sector's recovery pattern from 2021 onwards. All things considered, a given year's SGF could be higher or lower than that year's SGF under a non-COVID-19 scenario. The compounded effect on the year's SGF will determine the magnitude and nature of the impact on the total CORSIA offsetting requirements for that year, as well as the associated costs for the industry.
  • The calculation of an aeroplane operator's annual offsetting requirements during CORSIA's pilot phase (2021 to 2023) requires multiplying the corresponding year's SGF with an emissions value of the operator. For the latter, States can choose, for their attributed operators, between two options: an operator's emissions in a given year (i.e. 2021, 2022 and 2023 emissions); or the operator's 2020 emissions for each of the three years during the pilot phase. Therefore, the impact of COVID-19 on the annual offsetting requirements during CORSIA's pilot phase is not only through the impact on a given year's SGF (as described above), but also through a State's choice of reference emissions.
  • CORSIA refers to a certain percentage (0.1%) of global CO2 emissions in 2020 as a threshold for a new entrant operator to be covered by the CORSIA offsetting requirements. Therefore, any impact on the 2020 emissions due to COVID-19 may create the need to review this provision.


Considerations on the need and timing to adjust the CORSIA baseline and other design features above, if appropriate, need to be based on proper technical data and assessment. On the matter of timing, for potential adjustments, due consideration has to be given to the timeline for CORSIA implementation, as described in Appendix 1 of Annex 16, Volume IV, and to the related milestones, as follows:

  • 31 October 2022: the SGF value corresponding to year 2021 CO2 emissions will be provided by ICAO in order for States to calculate the 2021 offsetting requirements of individual aeroplane operators attributed to them; this will be the first instance in which information on CORSIA's sectoral baseline will be applied.
  • 31 January 2025: deadline for aeroplane operators to cancel eligible emissions units to comply with their total offsetting requirements for CORSIA's pilot phase (2021 to 2023). Annex 16, Volume IV does not specify any date for the purchase of units by operators

ICAO response

Any adjustment to CORSIA's design features is a matter that requires careful consideration by the relevant ICAO bodies. The ICAO Council, at the 220th Session in June 2020, considered an analysis by the Committee on Aviation Environmental Protection (CAEP) on the COVID-19 impact on CORSIA's design features. 

In addition to the impact assessment, the Council also considered the legal and reputational aspects related to the various options, as well as the importance of maintaining the originally-agreed balance between the scheme's economic impacts and environmental benefits together with its simplicity and practicality, whilst responding to this unprecedented crisis.

The Council agreed that, in order to safeguard against inappropriate economic burden on aeroplane operators, 2020 emissions should not be used for the three CORSIA design features listed above. In this regard, the Council decided that during the pilot phase, 2019 emissions shall be used for 2020 emissions and published in all relevant ICAO documents referenced in Annex 16, Volume IV. There was no change for the provisions of Annex 16, Volume IV or Assembly Resolution A40-19 text.

2022 CORSIA periodic review

Paragraph 17 of Assembly Resolution A40-19 includes a provision that the ICAO Council will conduct a periodic review of the CORSIA every three years from 2022. In this regard, the Council, in June2020, highlighted the importance of undertaking the 2022 periodic review, with technical contribution of the Committee on Aviation Environmental Protection (CAEP), which will offer an opportunity to examine the impact of COVID-19 on CORSIA on various issues, including the impact on the baseline beyond the pilot phase. 

In March 2021, the ICAO Council agreed on the process and methodology for the CORSIA periodic review toward 2022, and on the framework for the consideration of inputs from its subsidiary bodies (such as the CAEP and the TAB). Any recommendations by the Council will be forwarded for consideration by the 41st ICAO Assembly scheduled for 2022.

In June 2021, the updated CAEP scenario-based analyses on potential impacts of COVID-19 on CORSIA and its executive summary were presented to the 223rd session of the ICAO Council (C-WP/15209).

In November 2021, CAEP’s analyses in support of the 2022 CORSIA periodic review and its Executive  Summary were presented to the 224th Session of the ICAO Council (C-WP/15261), including an update of the CAEP analyses of COVID-19 impacts on CORSIA and CAEP’s initial assessment on the implementation of CORSIA, in particular the functioning of MRV provisions.

In March 2022, CAEP provided further inputs to the 225th Session of the ICAO Council regarding the 2022 CORSIA periodic review, including further assessment of COVID-19 impacts on CORSIA (C-WP/15326). In order to facilitate the Council's consideration of these inputs, CAEP structured such inputs in three components, namely:

Key takeaway messages contained in the CAEP inputs listed above were provided to the Council as an Executive Summary.

CAEP also provided, during the 225th Session of the Council, an informal briefing in relation to the CAEP inputs to the 2022 CORSIA periodic review.


In June 2022, the 226th Session of the ICAO Council requested CAEP to undertake further analysis on the impacts of COVID-19 on CORSIA and its baseline, building upon the analyses delivered by CAEP during the 225th Council Session in March 2022. The objective of the requested analysis was to estimate the CORSIA offsetting requirements and the regional breakdown, using the average of 2019 and 2020 emissions as the agreed baseline in Assembly Resolution A40-19, as well as the following scenarios for the CORSIA baseline after the pilot phase (2024 to 2035)

i. 2019 emissions only;
ii. a percentage of 2019 emissions, which reflects an equivalent level to the average of 2019 and 2020        emissions; and
iii. the mid-point between the baseline scenarios i) and ii) above;

This additional CAEP analysis, completed in late June, was presented to the ICAO Council on 24 August 2022 and is now available in the ICAO website here.

The ICAO Council, following consideration of the additional CAEP analysis and other design elements of CORSIA, agreed on a series of proposals for consideration by the 41st Session of the ICAO Assembly, namely: 
    • Use of 2019 emissions as the CORSIA baseline for the pilot phase (2021 – 2023);
    • Use of 85% of 2019 emissions as the CORSIA baseline after the pilot phase (2024 – 2035); and
    • Changes to the percentage use of the sectoral and individual operator's growth factors for the calculation of offsetting requirements under CORSIA, as follows: 
      • 2030 - 2032: 100% sectoral, and 0 % individual; and
      • 2033 - 2035: 85 % sectoral and 15% individual
The 41st Session of the ICAO Assembly considered the Council proposals and adopted the Resolution A41-22 on CORSIA including the design adjustments above, as reflected in Assembly Working Paper A41-WP/659, available at the ICAO A41 website. 


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