International Aviation

Critically Insufficient4°C+ World

This rating indicates that the target is consistent with warming of greater than 4°C if all other sectors were to follow the same approach.

Highly insufficient< 4°C World

This rating indicates that the target is consistent with warming between 3°C and 4°C if all other sectors were to follow the same approach.

Insufficient< 3°C World

This rating indicates that the target is consistent with warming over 2°C and up to 3°C if all other sectors were to follow the same approach.

2°C Compatible< 2°C World

This rating indicates that the target is consistent with holding warming below, but not well below, 2°C if all other sectors were to follow the same approach.

1.5°C Paris Agreement Compatible< 1.5°C World

This rating indicates that the target is consistent with the Paris Agreement’s 1.5°C limit.

In 2013, the ICAO Assembly set an aspirational goal of carbon neutral growth for international aviation from 2020 levels (ICAO, 2013). Carbon neutral growth means that net CO₂ emissions from international aviation remain constant compared to the baseline – which is was set at the average of emissions in 2019-2020 (paragraph 11, ICAO Assembly, 2016). Due to COVID-19, aviation emissions in 2020 were substantially lower than anticipated. This meant that the baseline for carbon neutral growth would have been lower than anticipated and the target more ambitious.

However, in June 2020, following a request from the trade organisation for airlines, the International Air Transport Association (IATA), the ICAO Council decided to change the reference year for CORSIA’s pilot phase to 2019, missing the opportunity to commit to a more ambitious target (IATA, 2020; ICAO, 2020d).

The ICAO Assembly will decide in 2022 on the rules for the first and second phase starting in 2024. Because the baseline for 2024 and beyond is currently uncertain, we use a range for the baseline. Emissions in 2019 form the upper bound and average emissions in 2019 and 2020 the lower bound – with 2020 emissions 54% lower than 2019 emissions (based on (CAEP, 2021))For the period, 2021-2023, we use the 2019 baseline. We calculated 2019 emissions to be 609 MtCO₂ and average 2019-2020 emissions to be 445 MtCO₂.

We rate the target of carbon neutral growth from 2020 as ‘critically insufficient’. Under the CAT’s rating methodology, the upper end of the target range in 2030 alone would be rated ‘highly insufficient’. Because the international aviation sector plans to rely on emission units and alternative fuels that are unlikely to deliver sufficient real emission reductions, we downgrade the rating to ‘critically insufficient’. If the baseline were to be the average of emissions in 2019 and 2020, with 2020 emissions 54% lower than in 2019, the 2030 target emission levels would fall in the ‘insufficient range'. The CAT would downgrade this rating to ‘highly insufficient’ for the reasons mentioned above.

Further, a significant shortcoming of ICAO’s approach is that the target of carbon neutral growth covers only CO₂ and not non-CO₂ emissions – such as NOX and contrail cirrus – and their climate impact. Researchers have estimated that overall emissions from aviation warm the climate at three times the rate of CO₂ emissions from aviation alone (Lee et al., 2021). Efforts to reduce the climate impact from international aviation must include the full scope of climate effects and aim to bring all emissions to zero.

To be Paris-Agreement compatible, carbon emissions from international aviation should be below 300 MtCO₂ in 2030 and decrease to zero by 2060. The sector should also take measures to substantially reduce non-CO₂ climate impacts. The carbon neutral growth goal is insufficient to reach these required emission levels.

Impact of COVID-19 on the CORSIA baseline

The baseline for CORSIA was originally set at the average 2019-2020 emissions level. However, because of the impact of COVID-19 and after a request from IATA (IATA, 2020), the ICAO Council decided that 2019 alone will be taken as the reference year for CORSIA’s baseline until at least 2023. In 2022, the ICAO Assembly will take a decision on the baseline for CORSIA’s first and second phase (i.e. 2024-2035) (ICAO, 2020d).

Researchers found that with 2019 emissions as the baseline for carbon neutral growth, aircraft operators face limited to no offsetting obligations in CORSIA’s pilot phrase from 2021 to 2023 (Schneider and Graichen, 2020). If the rules had remained unchanged and average 2019-2020 emissions had been taken as the baseline, COVID-19 would not have substantially changed the offsetting requirements that airlines face under the scheme because the lower baseline and lower future emissions would have cancelled each other out (Schneider and Graichen, 2020).

Impact of the COVID-19 pandemic on future emissions from international aviation is highly uncertain. Estimates for full recovery range from three to fifteen years (CAEP, 2021; Czerny et al., 2021; Grewe et al., 2021). Given the uncertainties around the trajectory recovery, we have determined two scenarios to cover a wide range of possible future emissions. First, we assume a fast recovery scenario, in which emissions from international aviation will remain below 2019 emissions until 2023. Second, we assume a slow recovery scenario, in which it takes until 2029 before international aviation emissions are back at pre-COVID levels. As can be inferred from the graph, under these scenarios, airlines will face little to no offsetting obligations under CORSIA in the pilot and first phase (as CORSIA applies on a route-basis, it is possible that airlines will face some offsetting obligations on specific routes).

Country targets: NDCs and net zero

To keep the Paris Agreement 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 national governments must include international aviation in their NDC targets.

CAT provides an overview analysis of international aviation coverage in governments’ updated and second NDCs and evaluates government net zero targets on the individual country pages. None of the 196 NDCs include a specific target for emissions from international aviation. The EU and its 27 member states include emissions from outgoing flights in its NDC (Germany and the European Commission, 2020). The United States, the United Kingdom and Panama state in their NDCs that they will work through ICAO to reduce emissions from international aviation (Government of Panama, 2020; UK Government, 2020; US Government, 2021).

The United Kingdom included emissions from international aviation and shipping in its sixth carbon budget for the period 2033-2037 (BEIS, 2021). While the 2019 Climate Change Act does not specifically mention emissions from international bunkers, the UK Government stated that these emissions are included in its 2050 net zero target, which was set on an economy-wide basis (BEIS, 2021).