To keep the Paris Agreement 1.5˚C temperature goal within reach, it is imperative that global CO2 emissions reach net zero around 2050. The Paris Agreement requires developed countries to set economy-wide emission reduction targets and developing nations to work towards those (UNFCCC, 2015). This implies that governments must include international aviation in their NDC targets.
Just four countries are responsible for a quarter of international aviation emissions. These are the EU27 (10.4% in 2019), the United States (7.9% in 2019), China (4.4% in 2019) and the United Kingdom (3.9% in 2019) (Graver, Rutherford and Zheng, 2020). Japan, the United Arab Emirates and India are other important players – all responsible for 2–3% of global CO2 emissions from international aviation in 2019. Within the European Union, Germany, France and Spain have the highest emissions from international aviation (Graver, Rutherford and Zheng, 2020).
While some countries have started addressing emissions from international aviation, there is wide variation in how governments define ‘international aviation’. The United Kingdom, for instance, covers emissions from all outgoing flights in its sixth carbon budget, but does not include emissions from incoming flights. The US net zero GHG aviation goal does not cover all outgoing and/or incoming flights, but rather covers emissions from flights operated by American airlines between two countries. For instance, if American Airlines flies between London and Paris, the emissions from that flight are covered, but if Air France flies from New York to Paris, the emissions from that flight are not included in the US goal.
The EU and its 27 member states include emissions from outgoing flights in their NDC (Germany and the European Commission, 2020). The EU is currently in the process of revising its climate, energy, and transport-related legislation. As part of the ‘ Fit for 55’ package, the Commission proposed a revision of the EU ETS, the implementation of a kerosene tax, and quota for the use of SAF in July 2021 (European Commission, 2021a, 2021c, 2021d, 2021b).
EU ETS Directive
The EU Emission Trading Scheme (EU ETS) originally covered flights to and from the European Economic Area (EEA) – which covers all 27 EU member states, Norway, Liechtenstein and Iceland until 2012 when involvement was suspended pending developments in the ICAO context (European Parliament and Council, 2013). Since January 2020, the EU ETS and the Swiss are linked and flights between the EEA and Switzerland are covered by these schemes. Flights from the EEA to the UK are covered by the EU ETS, while flights from the UK to the EEA are subject to the UK ETS.
To allow the continuation of developing a global approach to limiting emissions from international aviation through ICAO, the EU “stopped the clock” in April 2013, limiting EU ETS coverage to flights taking off and landing within the EEA (European Parliament and Council, 2013). The EU later extended this suspension to the end of 2023 (European Parliament and the Council of the European Union, 2017).
Key elements of the legislative proposal for revision of the EU ETS are (European Commission, 2021c, 2021b):
1) The EU ETS will continue to cover flights within the EEA and flights to Switzerland and the United Kingdom continue to be covered;
2) The EU ETS will cover flights between the EU’s outermost regions, and between the EEA and outermost regions;
3) To ensure equal treatment on routes, flights to and from countries that are not implementing CORSIA would be exempt from EU ETS or CORSIA obligations. To incentivise the full implementation of CORSIA, starting in 2027, this exemption applies until 31 December 2026.
4) The number of free allowances to aircraft operators will be gradually phased out to reach full auctioning by 2027; and
5) The EU ETS’s cap will be reduced.
The Commission proposes to apply CORSIA on flights between the EEA and countries that participate in CORSIA. Eligible offset credits need to originate from countries that participate in the Paris Agreement and CORSIA and double counting must be avoided.
While the Council of the EU agreed to this proposal, the European Parliament adopted various amendments to the Commission’s draft revisions to the EU ETS Directive (Council of the EU, 2022a; European Parliament, 2022b). Notably, the Parliament proposed an amendment calling on the Commission to submit a legislative proposal extending the EU ETS to cover non-CO2 emissions from aviation by the end of 2026 at the latest (Amendment 11). Until the adoption of such a legislative proposal, the CO2 emissions factor for international aviation should be multiplied by 1.8 by 31 December 2027, by 1.9 from 31 December 2028 and by 2.0 from 31 December 2029.
The Parliament also proposed amending the EU ETS to cover all departing flights from airports within the EEA, regardless of whether these flights are covered by CORSIA (Amendment 17). To avoid a double application of CORSIA and the EU ETS, the Parliament proposed that on flights between the EEA to countries applying CORSIA, airlines can deduct the financial value of CORSIA credits from their obligations under the EU ETS.
The Commission proposes implementing a tax on kerosene used on intra-EU private and commercial flights, which will be gradually implemented at a rate of zero EUR/GJ in 2023 to reach the minimum rate of 10.75 EUR/GJ in 2033 (European Commission, 2021a).
Quota for the use of SAF
The Commission proposed requiring fuel suppliers and aircraft operators to blend a minimum rate of sustainable aviation fuel with kerosene, starting at 2% in 2025 to 32% in 2040 and 63% in 2050. By 2050, at least 28% of the SAF must be synthetic aviation fuels (European Commission, 2021e). The European Parliament wants to increase these minimum shares to 37% by 2040 and 85% by 2040. It also proposed creating a Sustainable Aviation Fund from 2023 to 2050 to support investments in SAFs, new technologies and research into new engines (European Parliament, 2022a). The Council of the EU proposed minimum shares of 32% and 63% SAF by 2040 and 2050, respectively (Council of the EU, 2022b).
The United Kingdom included emissions from international aviation and shipping in its sixth carbon budget for the period 2033–2037 (BEIS, 2021). Emissions from international aviation cover outgoing flights only. While the 2019 Climate Change Act does not specifically mention emissions from international bunkers, the UK Government stated that these emissions are included in the net zero target for 2050, which was set on an economy-wide basis (BEIS, 2021).
In July 2022, the UK Government presented its Jet Zero strategy, which is to bring the UK aviation sector to ‘net zero’ by 2050. However, in this context, ‘net zero’ does not mean net zero, and eliminating the negative climate impacts of aviation by 2050, but rather allowing for an increase in emissions that need to be offset through the UK ETS, CORSIA and other offsetting mechanisms outside the aviation sector. Although non-CO2 emissions and impacts contribute to an estimated two-thirds of aviation’s radiative forcing (Lee et al., 2021), the Jet Zero strategy does not set clear targets for their elimination.
The UK Government states that it can achieve “Jet Zero” without government interventions to limit growth in aviation demand (Department for Transport, 2022). It envisages that demand could grow by 70% between 2021 and 2050. This runs counter to the advice of the UK Climate Change Committee, which stated that no net expansion in airport capacity should be permitted, and passenger growth should be 25% maximum from 2018 levels (CCC, 2020).
The Government expects that the UK ETS and CORSIA will reduce emissions by around 25% - however, as explained under CORSIA, the scheme is highly unlikely to drive any significant CO2 reductions from aviation. The UK Government further plans to offset emissions through Greenhouse Gas Removals, including Direct Air Capture, a technology that is not yet mature, and has a highly uncertain abatement potential (Fuss et al., 2018; Jeffery et al., 2020).
There is limited global potential for capturing CO2 from the atmosphere and permanently storing it (Fuss et al., 2018; Jeffery et al., 2020). This limited potential, if used at all, should be reserved to balance out residual emissions to achieve net zero global emissions, rather than to facilitate a stark increase in aviation sector emissions in one of the world’s wealthiest countries.
The UK Government also expects SAF to play an important role and commits to have at least 10% SAF in the UK fuel mix by 2030 (Department for Transport, 2022). While SAFs will be key in decarbonising the aviation sector, countries should be careful to over rely on this technology as its production is still in its infancy stage and SAFs are 2-8 times as expensive as standard jet fuel (Pavlenko, Searle and Christensen, 2019). SAFs account for less than 0.1% of global aviation fuel supply today (Boehm et al., 2021) and massive investments in renewable energy are needed to upscale production. As other sectors also rely on renewable energy to decarbonise, there will likely be competing demand for existing and new renewable energy capacity.
The United States committed to net-zero GHG emissions from the US aviation sector by 2050 (FAA, 2021). This goal covers CO2, N2O and CH4 emissions but not other climate impacts from aviation such as cirrus trails.
The ‘US aviation sector’ is defined as (1) domestic aviation (i.e. flights departing and arriving in the US and its overseas territories); (2) flights operated by US airlines between two countries (e.g. a flight between the UK and EU operated by American Airlines would be covered, but a flight from the US to the UK operated by British Airways would not); and (3) emissions from US airports.
Proposed actions include operational improvements, new aircraft technologies and sustainable aviation fuels. The US government recognises that offsetting may be needed to bring the aviation sector to net zero, but provides no further details (FAA, 2021).
We have not identified any commitments or policies related to international aviation.
In the United Kingdom, the aviation industry committed to net zero CO2 emissions by 2050, in line with the UK Government targets (Sustainable Aviation, 2019). The industry, like the UK government, does not see any need for demand measures.
According to the industry’s Decarbonisation Roadmap, the UK can accommodate an increase in passenger numbers of 70% in the next three decades but acknowledges that new technologies, operational improvements and SAFs will not be able to keep up with this increase in demand. Rather, the EU ETS, CORSIA and carbon removal measures will be key in bringing British aviation emissions to net zero.
The industry commits to make use of natural and technology-based carbon removals, but neither of these are solutions to count on. Natural carbon removals, such as sequestration in forests, bring a high risk of impermanence: the sequestered carbon will be released back into the atmosphere within years to centuries, negating any benefits of sequestering it in the first place. The potential for natural carbon removals is limited and needed to balance out residual global emissions – again, it is questionable as to whether this solution should be used to ‘neutralise’ a stark increase in emissions growth in the world’s wealthiest nations.
The European aviation industry has drafted a pathway to net zero CO2 emissions from aviation by 2050 (NLR - Royal Netherlands Aerospace Centre and SEO Amsterdam Economics, 2021). It foresees a major role for sustainable aviation fuels and hydrogen (by 2050, these two technologies would reduce BAU emissions by 54%) and a small role for economic measures ( a contribution of 8% below BAU by 2050) (NLR - Royal Netherlands Aerospace Centre and SEO Amsterdam Economics, 2021).
In February 2022, European countries and aviation industry groups signed the Toulouse Declaration, reaffirming their commitment to net zero carbon from international aviation by 2050 (ACI Europe, 2022).