The 50%+ gap in fuel efficiency suggests there is a large and underestimated potential for in-sector CO₂ emission reductions. This highlights the role for additional policies to limit aviation emissions, notably the CO₂ standard being developed by the international civil aviation organization (ICAO) and a global market-based measure (MBM) to price aviation carbon.

—“Transatlantic Airline Fuel Efficiency Ranking, 2014”

The new ICCT report compared the top 20 airlines on transatlantic routes in terms of fuel efficiency (i.e., carbon intensity) in 2014. Among the highlights of the report:

• The three least-efficient airlines (Lufthansa, SAS, and British Airways) were collectively responsible for one-fifth of transatlantic available seat kilometers and burned 44%-51% more fuel per passenger kilometer than the most efficient.

• A nonstop round-trip transatlantic flight averaged about one tonne of CO₂ emissions per passenger, equivalent to emissions from a 35-kilometer daily commute in a Toyota Prius over a work year.

• Seating configuration and aircraft fuel burn (i.e., fuel economy of the aircraft operated) are the two most important factors influencing airline fuel efficiency; together they explain about 80% of the variation in fuel efficiency among the airlines studied.

• Passenger load factor (i.e., percentage of seats filled) and freight carriage are relatively less important drivers of fuel efficiency.

• Airlines that have invested in new, advanced aircraft are significantly more fuel-efficient than airlines flying older planes, highlighting the crucial role of technology (and thus performance standards) in driving down fuel consumption and associated carbon emissions.

• The impact of premium seating on emissions is substantial: first class and business seats accounted for only 14% of available seat kilometers flown on transatlantic routes but approximately one-third of total carbon emissions. For carriers such as British Airways and Swiss, premium seating was responsible for almost one-half of their total emissions from passenger travel.

Aircraft emitted about 700 million metric tons of CO₂ in 2013. Absent policy interventions, aviation emissions are on pace to triple by 2050—a period in which many developed countries hope to reduce their emissions by up to 80%.

Fuel efficiency of the top 20 airlines on transatlantic routes, 2014. Source: ICCT. Click to enlarge.

Delegates to the 21^st session of the Conference of the Parties to the UNFCCC (COP 21) will be meeting in early December at Le Bourget Airport in Paris to discuss, among other issues, how to incorporate greenhouse gas emissions from international aviation into a global climate protection framework.

The International Civil Aviation Organization (ICAO) has committed to develop a global framework—an aircraft CO₂ standard and a framework for market-based measures—for controlling CO₂ emissions from aviation by 2016. However, the process has been hampered by disagreements over how to equitably distribute reduction targets by country or carrier.

The European Union in 2012 suspended its action requiring foreign air carriers flying to or from EU airports to participate in the EU Emissions Trading System. The US Environmental Protection Agency in 2015 published a draft “endangerment finding”—the first formal step toward regulating aviation greenhouse gases under the Clean Air Act. The eventual outcome will be a rule to limit emissions—either US domestic enforcement of ICAO’s CO₂ emission standard for new aircraft or a more stringent US–only aircraft standard.