MEIG Highlights, Latest News 23 mai 2022

Highlight 34/2022 – Will CORSIA lead to a carbon-neutral aviation sector?

Samuel Duelli, 23 May 2022

Source: ICAO

Aviation was responsible for around 2.4% of anthropogenic greenhouse gas (GHG) emissions in 2019. The aviation sector needs to reduce its emissions and achieve carbon neutrality, just like any other sector, to reach the goal of less than 1.5°C global warming. [1] As decarbonizing the aviation sector is quite challenging, different strategies may be used to reach net-zero carbon emissions. In 2009, the International Civil Aviation Organization (ICAO) agreed on three targets:

  1. Annual fuel efficiency improvement by 1.5%.
  2. CO2 neutral annual industry growth from 2020 onwards.
  3. Halving CO2 emissions by 2050 compared to 2005 levels (International Air Transport Association (IATA) has dedicated itself to reaching net-zero CO2 emissions by 2050).

In 2016, ICAO agreed to implement a market-based measure to address and achieve those goals (especially goals 2 and 3) called Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). It is the first market-based measure that has been implemented at international level for an industry.

The primary purpose of CORSIA is to facilitate carbon offsetting for airlines. It has a phased implementation with a Pilot Phase (2021-2023), Phase 1 (2024-2026) and Phase 2 (2027-2035). In the first two phases, only flights on routes with two states that volunteered are subject to offsetting requirements. From 2027 onwards, all states have to offset emissions that exceed the baseline emissions. States with low aviation activity and least developed countries, small island developing countries and landlocked developing countries are exempted from these rules. However, they can voluntarily participate in the offsetting scheme. The scheme also allows for emission reductions by CORSIA-permitted alternative fuels with lower emissions than Jet-A fuel, leading to in-sector CO2 emission reductions. If an airline uses such fuels and blends them with Jet-A fuel, it can claim in-sector CO2 reductions and may reduce its costs for offsetting.[2],[3]

Currently, the price for one offsetting certificate (equal to one tonne of CO2) is much lower than for one tonne of CORSIA allegeable alternative fuel (e.g., sustainable aviation fuel (SAF)). Therefore, with the current price, in-sector reductions are not very feasible. Nevertheless, the price for offsetting certificates has increased in the last year and may further increase in the coming months and years. Further increases in the price might incentivize airlines to invest in sustainable aviation fuels, leading to in-sector CO2 emission reductions. If the current high prices for kerosene persist, airlines also have more incentives to invest in SAF. Since the beginning of 2022, 107 states have been volunteering in CORSIA. With that, over 77% of international aviation activity is captured. However, CORSIA only includes international flights while excluding domestic flights, which also have an essential role in global CO2 emissions by aviation. Excluding these may not lead to reaching net-zero for the whole industry. Nevertheless, CORSIA is an important starting point in achieving net-zero CO2 emissions in the aviation sector.[4],[5] Hence, CORSIA alone will not lead to a carbon-neutral aviation sector, but it is a good first step into the right direction.

Samuel Duelli, Highlight 34/2022 – Will CORSIA lead to a carbon-neutral aviation sector?, 23 May 2022, available at

[1] Jaramillo, P. et al., 2022, Transport in IPCC, 2022: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (Chapter 10), p. 58

[2] Jaramillo, P. et al., 2022, Transport in IPCC (Chapter 10), p. 63

[3] Maertens et al., 2020, ICAO’s new CORSIA scheme at a glance – a milestone towards greener aviation?”, Aviation and Climate Change, Chapter 7

[4] Maertens et al., 2020

[5] Sharma et al., Would CORSIA implementation bring carbon neutral growth in aviation? A case of US full service carriers, Transportation Research Part D: Transport and Environment, Volume 97, August 2021, 102839

The views expressed in the MEIG Highlights are personal to the author and neither reflect the positions of the MEIG Programme nor those of the University of Geneva.


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