2. What is CORSIA and how does it work?

 

• Pilot phase (from 2021 through 2023) and first phase (from 2024 through 2026) would apply to States that have volunteered to participate in the scheme; and
• Second phase (from 2027 through 2035) would apply to all States that have an individual share of international aviation activities in RTKs in year 2018 above 0.5 per cent of total RTKs or whose cumulative share in the list of States from the highest to the lowest amount of RTKs reaches 90 per cent of total RTKs, except Least Developed Countries (LDCs), Small Island Developing States (SIDS) and Landlocked Developing Countries (LLDCs) unless they volunteer to participate in this phase.

States that voluntarily decide to participate the CORSIA may join the scheme from the beginning of a given year, and should notify ICAO of their decision to join by June 30 the preceding year.

In addition to paragraph 9 on the participation of States in the CORSIA, paragraph 10 defines the coverage of the scheme on the basis of routes between States: a route will be covered by the scheme if both States connecting the route are participating in the scheme; similarly, a route will not be covered by the scheme if one or both of States connecting the route are not participating in the scheme.

Once participation of States and routes covered by the CORSIA is defined in a given year from 2021, and offsetting requirements in the given year (i.e. increased emissions beyond the average baseline emissions of 2019 and 2020) are set, the requirements are distributed among aircraft operators participating in the scheme, as per the formula in paragraph 11 of the Assembly Resolution.

Paragraph 11 of the Assembly Resolution includes a concept of “a dynamic approach” for the distribution of offsetting requirements, which moves gradually from the use of 100 per cent sectoral approach (and 0 per cent individual approach) from 2021 to 2029, towards the use of individual approach of at least 20 per cent from 2030 to 2032; and at least 70 per cent from 2033 to 2035. “Sectoral approach” represents the international aviation sector’s global average growth factor of emissions in a given year, while “individual approach” represents an individual operator’s growth factor of emissions in a given year.

• What are the design elements in the CORSIA to address “administrative simplicity”, “environmental integrity” and “cost-effectiveness”?

  Participants in the 2015 Global Aviation Dialogues (GLADs) identified "administrative simplicity", "environmental integrity" and "cost effectiveness" as three most important considerations for the design of a global MBM scheme. Participants in the 2016 GLADs highlighted that paragraphs 9 (phased implementation), 11 (distribution of offsetting requirements) and 13 (technical exemptions) were closely linked to such major considerations.

• What are the design elements in the CORSIA to address “differentiation” in a practical way without impacting non-discrimination?

  Participants in the 2016 GLADs highlighted paragraphs 9 (phased implementation), 10 (route-based exemptions) and 11 (distribution of offsetting requirements) as the design elements to address differentiation in a practical way without impacting the non-discrimination principle.​

• What is the rationale for the phased implementation of the CORSIA?

   

  Paragraph 9 of the Assembly Resolution A39-3 on phased implementation intends to address "special circumstances and respective capabilities of States, in particular developing States, in terms of vulnerability to the impacts of climate change, economic development levels, and contributions to international aviation emissions" (as acknowledged in paragraph 8 of the Assembly Resolution).
  
  Under the phased implementation, States choose to voluntarily participate in the CORSIA at a pilot phase starting in 2021, or at a first phase starting in 2024. Second phase starting in 2027 would apply to all States that have an individual share of international aviation activities in RTKs in year 2018 above 0.5 per cent of total RTKs or whose cumulative share in the list of States from the highest to the lowest amount of RTKs reaches 90 per cent of total RTKs, except the exempted States
  

• What is the difference between the pilot phase (from 2021 through 2023) and the first phase (from 2024 through 2026)?

   

  Participating in the pilot phase and the first phase is voluntary. States participating in the pilot phase have two options to determine the basis of their aircraft operator’s offsetting requirement: they may either apply an aircraft operator’s emissions covered by the CORSIA in a given year (i.e. 2021; 2022 and 2023), or refer back to an aircraft operator’s emissions covered in a single year of 2020, in the calculation of offsetting requirements by paragraph 11.

  
  For the first phase, calculation to determine an aircraft operator’s offsetting requirement is based on the emissions in a given year (i.e. 2024; 2025 and 2026).

• Which criteria determine the participation or exemption from offsetting requirements for States under CORSIA in its 2nd phase from 2027? What is the relation of these criteria? How are RTK shares calculated?

   

  Paragraph 9 of the Assembly Resolution A39-3 determines the participation of States in CORSIA. Unlike the voluntary participation of States in the pilot and first phases from 2021 to 2026, the 2nd phase of CORSIA from 2027 applies to all Member States, with two categories of exemptions based on aviation-related criteria, and socio-economic criteria. These criteria for the exemption of States from the CORSIA offsetting requirements in the 2nd phase is defined in A39-3 paragraph 9 e).
  
  For aviation-related criteria, there are two thresholds which are:
  
  

  • States with an individual share of international aviation activities in Revenue Tonne Kilometers (RTKs), in year 2018 below 0.5 per cent of total RTKs; and
  • States that are not part of the list of States that account for 90 per cent of total RTKs when sorted from the highest to the lowest amount of individual RTKs.

  
  
  Revenue Tonne Kilometers or RTKs is the utilized (or sold) capacity for passengers and cargo expressed in metric tonnes, multiplied by the distance flown. In other words the RTK levels correspond to the volume of air transport activity. As an aircraft operator carries more passengers and cargo for a longer distance, the RTK levels of the operator get higher. A State’s RTK represent the total RTK levels of all aircraft operators registered to that State. Annual RTK data is being reported from Member States to ICAO as part of ICAO Statistics Programme, and published in the Annual Report of ICAO Council. RTK data for the year 2018 will be used for the purposes of determining the exemptions of States from offsetting requirements in the 2nd phase of CORSIA.
  
  A State’s individual RTK share is calculated by dividing the State’s RTKs by the total RKTs of all States. Those States who have an individual RTK share below 0.5 percent of the total RTK, will be exempt from offsetting requirements, unless the cumulative RTK share is less than 90 percent.
  
  The cumulative RTK share is calculated by sorting the individual RTK shares from the highest to lowest, then successively increasing the value by summing the RTK shares from highest to lowest until the value reaches 90%. The values of all States are considered for this calculation, regardless if a State might be exempted from offsetting requirements in CORSIA afterwards.
  
  In other words, a State whose individual RTK share is less than 0.5 percent but is part of the 90% cumulative RTK, is included in the 2nd phase. A State whose individual RTK share is less than 0.5 percent and not part of the 90% cumulative RTK, is exempted from offsetting requirements in the 2nd phase. The goal is to cover at least 90% of the international aviation activities in the 2nd phase of CORSIA.
  
  The second set of exemption criteria from offsetting requirements is based on socio-economic criteria. These States are defined as: Least Developed Countries (LDCs); Small Island Developing States (SIDS); and Landlocked Developing Countries (LLDCs). Regardless of the level of international aviation RTK share, these LDCs, SIDS and LLDCs are also exempted from offsetting requirements in the 2nd phase of CORSIA.
  
  Nevertheless, these exempted States from offsetting requirements by aviation-related criteria and socio-economic criteria are still encouraged to voluntarily participate in CORSIA.
  

• What is the rationale for the route-based approach?

   

  Paragraph 10 of the Assembly Resolution A39-3 defines the coverage of the CORSIA on the basis of routes between States, with a view to minimizing market distortions between aircraft operators on the same routes. For this purpose, the design approach is to provide equal treatment of all aircraft operators on a given route: a route is covered by the scheme if both States connecting the route are participating in the scheme, and a route is not included in the scheme if one or both States connecting the route are not participating in the scheme.
  
  By following this approach, when an aircraft operator calculates its CO2 emissions covered by the CORSIA in a given year, the operator needs to take into consideration emissions from its operations on all the routes covered by the scheme as per paragraph 10 of the Assembly Resolution.
  

• What does it mean by “participation of States and the route-based approach” and do those exempted States and operators need to do anything under CORSIA?

   

  According to paragraph 20 of the Assembly Resolution A39-3, all States whose aircraft operator undertakes international flights need to undertake a monitoring, reporting and verification (MRV) of CO2 emissions from international flights starting from 1 January 2019. The data is used for the calculation of the CORSIA baseline, which is the average of 2019 and 2020 emissions. On the other hand, States are encouraged to participate as part of the CORSIA offsetting requirements in all Phases. Due to the route-based approach, only flights between participating States will be included in the offsetting requirements under CORSIA.
  

• According to the route-based approach, can the characterization of a route as “covered” or “not covered” by the CORSIA change over time?

   

  Paragraph 10 of the Assembly Resolution A39-3 allows for the characterization of a route as “covered” or “not covered” by the CORSIA, on the basis of whether the States connecting the route are participating or not in the CORSIA.
  
  For example, in line with paragraph 9 of the Assembly Resolution, some States could voluntarily participate in the scheme in the pilot or first phases, while other States participate in from the second phase. Therefore, any additional participation by a State in the scheme could add the routes to and from that State into the scheme, depending on the status of the other States connecting to the routes.
  
  To give certainty of all the routes to be covered by the scheme, the Assembly Resolution sets a deadline of 30 June every year for States to notify ICAO of their intention to voluntarily participate in the scheme, or discontinue their participation, from 1 January of the following year.
  

• What would happen to the emissions coverage by CORSIA if an operator of a non-participating State flies on the routes between participating States (e.g. fifth-freedom traffic right)

   

  Because CORSIA is a route-based approach, these routes between participating States would be subject to the coverage of emissions offsetting requirements under CORSIA.
  

• What would happen to the emissions coverage by CORSIA if a State without an operator undertaking international flights decides to participate in CORSIA?

   

  States without an operator flying international flights are encouraged to participate in all phases of the CORSIA. If such a State decides to participate, flights to and from that State to other participating States are additionally included for CORSIA’s offsetting requirements, due to the route-based approach. The total international emissions coverage would ultimately increase, as more flights would require an emissions offsetting.
  

• How will the CORSIA apply to aircraft operators that will initiate activities after the entry into force of the scheme (so called “new entrant”)?

   

  Paragraph 12 of the Assembly Resolution A39-3 refers to “new entrants” as aircraft operators that commence an aviation activity falling within the scope of the CORSIA on or after its entry into force. This paragraph outlines criteria to determine when “new entrants” should start participating in the scheme, with the entry date being the earliest out of the following two:
  
  

  • after three years from commencing aviation activities; or
  • the year in which new entrant’s annual emissions exceed 0.1 per cent of total emissions in 2020.

  
  
  In other words, new entrants are exempted from the application of the CORSIA offsetting requirements for the first 3 years, or until its annual emissions exceed 0.1% of total 2020 emissions from the international aviation sector. The condition that applies first will determine when a new entrant’s emissions are subject to the offsetting requirements if it operates on the routes covered by CORSIA.
  
  It is important to note that emissions of a new entrant are still to be reported from the beginning, regardless of the exemptions from the CORSIA’s offsetting requirements.
  

• Does the CORSIA include provisions for very low international aviation activities?

   

  Paragraph 13 of the Assembly Resolution A39-3 provides the provisions to exempt low levels of international aviation activity from the application of the CORSIA, such as humanitarian, medical and firefighting operations. Aircraft operators using aircraft for such operations will not take into considerations emissions from these operations for the purpose of the scheme.
  
  This paragraph also defines exemptions for aircraft operators with a low level of annual emissions from their international aviation operations (10,000 metric tonnes of CO2 emissions per year), as well as for aircraft with less than 5,700 kg of Maximum Take Off Mass (MTOM), with a view to avoiding administrative burden from the application of the CORSIA for low international aviation activities.
  
  It should be clarified that the exemptions of States from the 2nd phase (A39-3 paragraph 9), route-based approach (paragraph 10) and exemptions of new entrants (paragraph 12) are related to the coverage of emissions for offsetting requirements and those exempted emissions still need to be part of reporting requirements.
  
  However, technical exemptions under the paragraph 13 apply both to offsetting requirements and reporting requirements. In other words, these low levels of international activity are outside the scope of CORSIA.
  

• How are aircraft operator’s offsetting requirements calculated?

   

  According to paragraphs 9, 10, 12 and 13 of A39-3, the coverage of emissions for CORSIA offsetting requirements is based on the participation of States in different phases and the route-based approach, together with the exemptions for new entrants and for very low international aviation activities. As the total emissions covered by CORSIA are expected to increase year by year, the emissions increase above the baseline levels would be the total amount of CO2 emissions to be offset in a given year. Paragraph 11 of the Assembly Resolution A39-3 addresses the distribution of the total amount of CO2 emissions to be offset in a given year among individual aircraft operators participating in the scheme. A dynamic approach for the distribution of offsetting requirements is introduced in this paragraph, starting from the use of 100 per cent sectoral approach (and 0 per cent individual approach) and moving gradually to higher percentages of individual approach in accordance with the following steps:
  
  a) for the pilot and first phases as well as the first compliance cycle of the second phase (from 2021 through 2029), 100 per cent sectoral approach (and 0 per cent individual approach) would be applied. “Sectoral approach” represents the international aviation sector’s global average growth factor of emissions in a given year, which will be solely used as a single factor to all individual operators participating in the scheme for their calculation of offsetting requirements; and
  
  b) from the second compliance cycle of the second phase (2030 through 2032), at least 20 per cent individual approach would be applied; and at least 70 per cent individual approach would be applied from 2033 to 2035, with the Council recommending to the Assembly in 2028 whether and to what extent to adjust the individual percentage. “Individual” represents an individual operator’s growth factor of emissions in a given year, which will start to be used from 2030 together with the sectoral percentage, gradually to higher percentages of the individual percentage, in order to calculate the offsetting requirements of individual operators participating in the scheme.
  
  In the Assembly Resolution, dynamic approach is applied from 2030, rather than from the start of the second implementation phase (2027), which provides equal treatment between aircraft operators participating in the first and second phase of the CORSIA in terms of calculation offsetting requirements.
  
  
  
  

• Please explain the details of the formula used to distribute offsetting requirements to individual operators.

   

  Paragraph 11 of the Assembly Resolution A39-3 addresses a formula used to distribute offsetting requirements to individual operators. The formula is defined as the “operator’s annual emissions” multiplied by a growth factor, which gives you the CO2 offset requirements of the operator.
  
  The concept behind the formula is based on the fact that there are different sizes of operators and that operators’ emissions will grow at different levels, yet a sector-wide growth factor calculated every year should be commonly used for all operators for the first 9 years of CORSIA, or from 2021 through 2029. During this period, a sectoral growth factor in a given year is multiplied by the operator’s emissions covered by CORSIA in that year, which will give the operator’s offsetting requirement in that year. This is defined as using a 100 percent sectoral approach.
  
  Every year from 2021 to 2029, based on the reporting of emissions data from aircraft operators to States, and from States to ICAO, a single sectoral growth factor will be calculated by ICAO and the single number will be universally used to calculate individual operator’s offsetting requirements.
  
  It should be noted that Resolution A39-3 provides flexibility to States in the first 3 years of CORSIA, or the pilot phase, where each State can choose to use in the formula either:
  
  

  • the operator’s emissions in year 2021, 2022 or 2023; or
  • the operator’s emissions referring back to a single year of 2020.

  
  
  From 2030 through 2032, a more dynamic approach will be implemented where an individual operator’s emissions growth will be used at least 20 percent in calculating offsetting requirements, meaning that the use of the sectoral approach is up to 80 percent. From 2033 through 2035, the percent for the use of the individual approach will be raised to at least 70 percent in calculating offsetting requirements, meaning that the use of the sectoral approach is up to 30 percent. According to the Assembly Resolution A39-3, paragraph 11, the exact percent shares of sectoral approach and individual approach for these periods will be determined by the Assembly in 2028.
  

• Why does the baseline of 2019-2020 average emissions need to change over time?

   

  From 2021, CORSIA is to offset the increase of emissions beyond the sectoral baseline, and the sectoral baseline is the average of total CO2 emissions between 2019 and 2020, with the route coverage by CORSIA in a given year from 2021.
  
  Emissions data for ALL international flights, regardless of being covered or not by CORSIA offsetting requirements, will be reported to ICAO from 2019. The baseline emissions for years 2019 and 2020 depend on the routes covered by CORSIA in a given year from 2021, and the baseline will change when the number of States participating in CORSIA changes.
  
  Paragraph 11(g) of the Assembly Resolution A39-3, notes that sectoral baseline will be re-calculated when the routes included in CORSIA change, for example, when new States volunteer to participate. This is done at the start of each year.
  

• How does a new entrant (or operator) affect the baseline?

   

  The sectoral baseline calculation will not be affected since the baseline for CORSIA includes the flights in 2019 to 2020 only.
  

• What is the difference between the “growth factor” used by the formula under CORSIA and the generally-used term “growth rate”?

   

  The growth factor is the percent increase in the amount of emissions from the baseline to a given year from 2021, compared to the emissions in that given year. Generally, the term growth rate refers to the percent increase in the amount of emissions from the baseline to a given year from 2021, compared to the emissions in the baseline.
  
  The growth factor as defined above is used by CORSIA, as the growth factor is multiplied with the individual operator’s emissions in that given year (not the individual operator’s emissions in the baseline) to calculate the individual offsetting requirements; thus total offsetting requirements would match with the increase of total emissions covered by CORSIA in that given year.
  

• Why do we need to know total emissions from international aviation? Why aren’t the total emissions covered by CORSIA sufficient?

   

  Knowing the total emissions from international aviation is important, due to several reasons:
  
  1) To assess the overall emissions coverage of CORSIA and track progress in achievement of the aspirational goal of carbon neutral growth from 2020.
  
  2) As States voluntarily participate in CORSIA and the route-based approach affects the emissions coverage of CORSIA, the baseline of average 2019 – 2020 emissions will be changed to reflect the route-based coverage by CORSIA in a given year from 2021. Total emissions from all international flights/routes need to be reported from 2019 to reflect the route-based coverage by CORSIA in a given year from 2021, into the calculation of the baseline emissions.
  
  3) The total emissions from international aviation in 2020 is a reference value, for which the exemptions are given for a new entrant whose annual emissions do not exceed 0.1% of the total 2020 emissions.
  

• Does the CORSIA include provisions to review its implementation and make adjustments if needed?

   

  Paragraph 9 g) of the Assembly Resolution A39-3 includes a provision that the Council will conduct a review of the implementation of the CORSIA every three years, starting in 2022. This review will include an assessment of the impact of the CORSIA on the growth of international aviation, and the results of this assessment will serve as an important basis for the Council to consider adjustments to the next implementation phase or compliance cycle, and as appropriate, to recommend such adjustments to the Assembly for decision.
  
  In addition, the purpose of the periodic review, as elaborated in paragraph 18 of the Assembly Resolution is to contribute to the sustainable development of the international aviation sector and to the effectiveness of the scheme. Review will assess, inter alia, the progress towards achieving ICAO’s global aspirational goal; the scheme’s market and cost impact on States and aircraft operators and on international aviation; and the functioning of the scheme’s design elements. Review will also involve consideration of the scheme’s improvements that would support the purpose of the Paris Agreement; and update the scheme’s design elements.
  
  A special review will be performed by the end of 2032 on termination of the scheme, its extension or any other improvements of the scheme beyond 2035.