A new International Council on Clean Transportation (ICCT) report finds that aviation emissions are increasing 70% faster than UN projections that already point to a tripling of CO₂ by 2050. In other words, the climate challenge for aviation is worse than expected.

The report was issued in advance of the UN Secretary-General Climate Summit starting next week, and also ICAO’s triennial assembly starting 26 September, which will discuss market-based measures for international aviation (CORSIA vs. EU ETS), the need for a 2050 climate goal for aviation, and also supersonic emissions.

The ICCT paper, “CO₂ emissions from commercial aviation, 2018,” summarizes the first detailed, global CO₂ inventory for aviation in 15 years, with emissions and traffic by country (domestic vs. international) summarized for 100+ countries plus route-based carbon intensities.

Other key findings from the report are:

• Total CO₂ emissions from all commercial operations—passenger movement, belly freight, and dedicated freight—totaled 918 MMT in 2018. That equals 2.4% of global CO₂ emissions from global fossil fuel use and a 32% increase over the past five years.

• Passenger transport accounted for 747 MMT, or 81%, of those emissions in 2018. The largest single regional market for aviation was Intra-Asia, accounting for one-quarter of total emissions, following by Intra-North America (18%), and Intra-Europe (14%).

• The least efficient route groups—flights within the Middle East and within Africa—emitted more than 30% more CO₂ to transport one passenger one kilometer than the worldwide average.

• Flights departing airports in the United States and its territories emitted about one-quarter (24%) of global passenger transport-related CO₂. Two-thirds of those emissions came from domestic flights. The top 5 countries for passenger aviation-related carbon emissions were rounded out by China, the United Kingdom, Japan, and Germany.

• 43% of aviation CO₂ was linked to passenger movement in narrowbody aircraft, followed by widebody jets (33%) and regional aircraft (5%). The remaining aviation emissions were driven by freight carriage and divided between “belly” freight carriage on passenger jets (11%) and dedicated freighter operations (8%).

• Passenger emissions were roughly equally divided between short-, medium-, and long-haul operations. The carbon intensity of flights averaged between 75 and 95 grams CO₂ per revenue passenger kilometer (RPK), rising to almost 160 g CO₂/RPK for regional flights less than 500 km.

  
  

  Share of passenger CO₂ emissions and carbon intensity in 2018, by stage length. Source: The ICCT.

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This data set is provided at a time when the climate impact of air transport is coming under increasing scrutiny. Airlines and governments are beginning to take heed, but existing policies such the ICAO’s CO₂ standard for new aircraft and its Carbon Offsetting and Reduction Scheme for International Aviation are not expected to reduce aircraft emissions significantly. Additionally, the ICAO has yet to codify a 2050 climate goal in the way the International Maritime Organization (IMO), its sister agency governing international shipping, already has for oceangoing vessels. Further action, supported by the best available science on aviation emissions’ impacts and data about where those emissions are originating from, is needed.

—Graver et al.

Resources

• Brandon Graver, Kevin Zhang, Dan Rutherford (2019) “CO₂ emissions from commercial aviation, 2018” Working Paper 2019-16