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Carbon Offsetting Scheme for International Aviation (CORSIA)


What is CORSIA?

Under the Carbon Offsetting Scheme for International Aviation (CORSIA), aircraft operators will be required to purchase offsets, or “emission units”, for the growth in CO2 emissions covered by the scheme. CORSIA aims to address any annual increase in total CO2 emissions from international civil aviation above 2020 levels.

In order to address the concerns of developing States and to take into account the special circumstances and respective capabilities of States, CORSIA will be implemented in phases.

From 2021 until 2026 the scheme will only apply to international flights between States that volunteer to participate in the pilot and/or first phase. All other international flights will be exempt.

From 2027, participation is mandatory for States meeting certain criteria related to their level of aviation activities, except Least Developed Countries (LDCs), Small Island Developing States (SIDs) and Landlocked Developing Countries (LLDCs) which are exempt, unless they volunteer to participate.

How CORSIA was adopted

At the 39th session of the ICAO Assembly in 2016, ICAO’s Member States adopted a global carbon offsetting scheme for international aviation. ICAO’s Carbon Offset and Reduction Scheme for International Aviation (CORSIA) is set to commence with a voluntary period (2021-2026) after which it will become mandatory.

By the end of the ICAO Assembly, 65 states had already volunteered to implement the scheme from its outset, covering approximately 80% of CO2 growth in 2021-2035. The historic significance of this agreement cannot be overestimated. CORSIA is the first global scheme covering an entire industrial sector. The CORSIA agreement has turned years of preparation into an effective solution for airlines to manage their carbon footprint.

By itself, CORSIA will not lead to a sustainable future for aviation. Along with this global market-based measure, the industry will continue to drive its four-pillar strategy on climate change, comprising improvements in technology, operations and infrastructure.

Watch what airlines are doing in preparation for the adoption of CORSIA


Why is a single global market-based measure necessary?

Many airlines fly into dozens of different countries on a daily basis, with some large airlines serving over a hundred different countries each day; they need to have a single point of accountability. If airlines are subject to a patchwork of national or regional CO2 taxes, offsetting mechanisms, emissions trading schemes and other carbon pricing instruments, compliance would be unnecessarily complex and costly.

This is why the industry favors a single, global market-based measure to address CO2 emissions from international aviation. Having a single measure not only reduces complexity, but also reduces the risk of market distortions as all airlines are subject to similar requirements.

While the costs of CORSIA will be significant, a global system will be more cost-effective for the airline industry to adjust to in comparison with increases in costs applied through national or regional schemes, which would create differing compliance requirements and the risk of market distortions.

CORSIA and the Paris Agreement

In the industry’s view, the agreement reached in ICAO does reflect the spirit of the Paris Agreement and the Principle of equity and common but differentiated responsibilities and respective capabilities, in the light of different national circumstances, through the phased implementation and the inclusion of a sectoral component in the calculation of the emissions to be offset by individual aircraft operators.

Furthermore, whilst under the Paris Agreement each State is to decide its own level of ambition and the measures it wants to implement to achieve its own goals (“nationally determined contributions”), such a voluntary, bottom-up approach would not be suitable for international air transport. For the air transport sector, one of the main benefits of a global MBM is to avoid a patchwork of national measures. This is why a single global market-based measure for international aviation is important.


The implementation of CORSIA from 1 January 2021 should obviate the need for existing and new economic measures to be applied to international aviation emissions on a regional or national basis. Therefore, as from 1 January 2021, all international flights to/from airports in Europe should be subject exclusively to CORSIA and removed from the scope of the EU ETS.

While domestic flights are beyond the scope of CORSIA, any market-based measures applicable to domestic flights should be aligned and made compatible with CORSIA to avoid regulatory fragmentation and to reduce the administrative burden for operators and Governments and minimize potential market distortions.

In the interim period (2017-2020), we welcome the European Commission’s proposal to prolong the exemption for flights between Europe and third countries from EU ETS. Read our paper on CORSIA and the application EU ETS to aviation (pdf).

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