The GHG emissions of air and maritime transportation have been outside the regulatory reach of the UNFCCC and its Kyoto Protocol since the get go.  Protocol Article 2.2 leaves it to developed country parties (listed on Annex I) to work toward industry self-regulation via the International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO). Early drafts of the Paris Agreement included proposals to bring these “bunkers” fuels under the new agreement, but they did not make the final cut.

So it is noteworthy that this week, ICAO proposed its first emissions standards for aircraft. The proposed rules are aimed at large aircraft – those weighing over 60 tons – which account for more than 90% of international aviation emissions.  The rules require all new aircraft to reduce fuel use and increase efficiency, with new designs as of 2020 and new deliveries of current in-production designs as of 2023. Production of aircraft designs that do not comply with these standards would stop by 2028.

Aviation emissions currently account for 2% of global CO2 emissions, which is equivalent to those of Germany or the UK. But the number of flights is expected to double by 2030.

Given that the United States accounts for half of global CO2 emissions from aviation, and that airplane travel accounts for 11% of all transportation emissions in the U.S., last year the EPA moved toward regulating US aviation emissions under the Clean Air Act by making an endangerment finding.   In this way, the U.S. would regulate its aviation transportation emissions akin to how it currently regulates domestic car and truck emissions through fuel efficiency standards that spur new, lower emitting designs.  But the EPA held off drafting its own rules, awaiting ICAO’s action that would bind the aviation industry worldwide and thus not put U.S. airlines at a disadvantage.