In 2009, the International Air Transport Association (IATA), the global trade association for cargo and passenger air carriers, set three goals for the reduction of carbon dioxide (CO2) emissions from aviation:
- An average improvement in fuel efficiency of 1.5% per year from 2009 to 2020.
- A cap on net aviation CO2 emissions from 2020 (carbon-neutral growth).
- A reduction in net aviation CO2 emissions of 50% by 2050, relative to 2005 levels.
These same goals were adopted by Airlines for America (A4A), the trade association for nine U.S. cargo and passenger air carriers. The International Civil Aviation Organization (ICAO) subsequently adopted a 2% efficiency goal for international aviation at its 37th Assembly in 2010.
IATA routinely shows their progress towards the first goal in their semi-annual Airline Industry Economic Performance report. In the 2018 Mid-Year Report, the group projected a global fleet fuel efficiency of approximately 32.5 liters of fuel burned per 100 revenue tonnes of passengers and cargo transported one kilometer (100 RTK) by the end of the year. The rate of improvement has varied over time – from about 3% per year between 2009 and 2014, down to about 1.4% since – but overall the 19% improvement from the 2009 baseline of approximately 40 liters per 100 RTK averages out to a compound average fuel efficiency improvement of 2.3% per year. This exceeds both IATA’s and ICAO’s goal.
While I have no reason not to believe the figures IATA presents in its worldwide airline industry performance reports, “trust, but verify” is always a good policy. I do not have access to IATA’s data, but I do have the fuel burn and revenue ton-miles (RTM) data reported by U.S. air carriers to the U.S. Department of Transportation, as well as operations data reported in annual filings to the U.S. Securities and Exchange Commission. Let’s take a look and see how the U.S. air carriers are faring in reaching an average improvement in fuel efficiency of 1.5% per year.
I calculated fuel burn and RTMs for U.S. cargo and passenger airlines with annual revenue of at least $20 million for every year from 2009 through 2017, including mainline, regional, defunct, and merged carriers. Figure 1 below shows the results. As the red line falls, less fuel is burned to transport the same payload mass over the same distance, so fuel efficiency is improving.
The U.S. airlines are on track to achieve their goal of an average improvement in fuel efficiency of 1.5% per year, based on a compound average annual rate, shown as the dashed gray line in the figure above. They are short of ICAO’s goal of 2% improvement, which as noted above applies to international, not domestic aviation.
The above graphic is for all of the U.S. carriers. The fuel efficiency improvements of the U.S. carriers that are members of Airlines for America are shown in the figure below. Starting in 2014, average fuel efficiency improvements for the nine airlines started tracking above the grey, dashed 1.5% average trend line. After a couple years of stagnation, improvements started to pick up, and the average fuel efficiency edged back towards the goal line.
I’m optimistic that the U.S. carriers will achieve the goal they set out for themselves in 2009 of an average annual increase in fleet fuel efficiency of 1.5%. With air carriers taking deliveries of new, fuel-efficient aircraft beginning at the end of this year – Boeing 737 MAX aircraft to Alaska, American, Southwest, and United; Airbus A220 aircraft to Delta; Airbus A320neo aircraft to Spirit – there’s no reason to believe that the total fuel efficiency improvement since 2009 will be less than 14% by the end of 2019.
As shown in our recent working paper, in the U.S., revenue tonne-kilometers and overall fuel use have increased each year since 2009. The rapid growth in passenger airline demand outstripped fuel efficiency improvements, which caused overall fuel use and CO2 emissions to increase by 16 percent in 2017 versus 2009. So these fuel efficiency improvements have not been enough to reduce absolute fuel use and emissions.
Although absolute fuel use and CO2 emissions haven’t decreased, its positive that U.S. airline efficiency continues to improve despite a lack of leadership from the U.S. government. In 2015, the U.S. submitted to ICAO an action plan to reduce its aviation greenhouse gas emissions. It included an aspirational goal of achieving carbon-neutral growth for U.S. commercial aviation by 2020, using 2005 emissions as a baseline. The action plan also stated the U.S. EPA intended to issue an Advanced Notice of Proposed Rulemaking as a step to implementing a domestic aircraft CO2 emission standard. ICAO established a global aircraft CO2 standard in 2016, and we are still waiting on the U.S. to develop its own.
In 2016, ICAO finalized the details of a market-based measure (Carbon Offsetting and Reduction Scheme for International Aviaition, or CORSIA) to offset most of the growth in aviation CO2 emissions beginning in 2020. While CORSIA excludes domestic aviation activity, which is a majority of the operations of U.S. carriers, it does set up groundwork for the industry to achieve their second goal.
The third goal is going to be the hardest to achieve. A 50% reduction in CO2 emissions from 2005 levels by 2050 is both ambitious and necessary. United Airlines recently reaffirmed their commitment to this goal, although has declined to say whether it intends to meet the goal on an absolute or net (including offsetting) basis. Committing to an absolute goal would be a critical step toward putting aviation on a path to decarbonize, in contrast to its current status as the last real refuge of carbon offsetting.
I have thirty-some-odd years left in my career. I’ll be keeping track of the airlines’ progress towards the last goal, supporting them where I can, and offering a reality check when needed.