While global aircraft emissions do not fall under the purview of the Paris Agreement, the International Civil Aviation Organization (ICAO) has nevertheless been making strides toward regulating aviation carbon dioxide emissions.
Last week at the conclusion of its 39th Assembly Meeting, ICAO members recommended for adoption “the first-ever global market-based measure adopted by an entire industry sector.” The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) standards are designed as market-based measures to work alongside the airline industry’s whole “basket of measures,” with the goal of achieving “carbon neutral growth from 2020.” Other tools in the basket include technology improvements, alternative fuels, and operational changes.
The airline industry is among the fastest growing sources of carbon dioxide emissions, currently responsible for more than 3% of the world’s GHG emissions and projected to “increase seven times by 2050 compared to 1990 levels.” While aircraft manufacturers have already made significant progress on the technology front, ICAO claims that those developments alone would not achieve carbon neutral growth.
CORSIA will complement other developments in aircraft emissions regulation. Earlier this year, ICAO proposed the first global carbon dioxide emissions standards for aircraft. These standards call on aircraft manufacturers to use certain technologies in new models of aircraft starting in 2020 in order to improve fuel efficiency. Together with the other items in the basket of measures, these carbon dioxide emissions standards and the CORSIA program will help mitigate the aviation industry’s impact on climate change.
According to ICAO’s 2016 Environmental Report and Appendix B of the draft resolution, the CORSIA scheme requires airlines to purchase offsets to compensate for their portions of carbon dioxide emissions that exceed the country’s baseline. This baseline is calculated based on airline market shares and the country’s projected 2020 aviation emissions levels. The program will apply in a series of phases. The pilot phase (2021–2023) and first phase (2024–2026) will both be voluntary for any country that would like to begin participating in the program before 2027. Indeed, a surprising number of countries have already signed up to do so. In the pilot phase, countries will have flexibility to choose the basis for offsets whereas the first phase will require a specific calculation for determining the offsets. CORSIA goes live in 2027, when all countries except LDCs, SIDS, LLDCs, and “states with very low levels of international aviation activity,” will be required to implement the scheme. However, if one or both countries on the route is exempt and not participating in the program, CORSIA offsets will not apply to that route.
Some claim that ICAO’s CORSIA scheme does not go far enough to reduce carbon dioxide emissions. Groups like Transport and Environment question the effectiveness of offsets and argue that the standards are not rigid enough to achieve carbon neutral growth. However, others such as Boeing are supportive of these new measures, applauding ICAO for helping industry curb aviation emissions.
In addition to these developments at ICAO, the United States has also been constructing the framework to regulate aviation GHG emissions. In August, EPA issued an endangerment finding, which concluded that six greenhouse gas emissions (carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride) “endanger public health and welfare” under the Clean Air Act. This conclusion paves the way for EPA to regulate aircraft emissions domestically.