As the aviation industry grapples with rising environmental concerns, a new report underscores the stark limitations of sustainable aviation fuels (SAFs) in meeting future demand. While these alternative fuels present a promising avenue for reducing aviation’s carbon footprint, experts caution that their production cannot keep pace with the projected growth in air traffic.
The Limitations of Sustainable Aviation Fuels
Sustainable aviation fuels are touted as a key technology for replacing traditional fossil kerosene in aviation. However, a recent analysis led by Aéro Décarbo, alongside the non-profit think tank The Shift Project, reveals significant hurdles. The report asserts that the production of SAFs—particularly e-SAFs—will not be sufficient to curb the industry’s carbon emissions in the near to medium term. “SAFs are crucial for reducing aviation’s carbon output,” the report states, “but their deployment will lag behind demand, preventing a substantial decrease in CO2 emissions by 2050.” Currently, aviation is responsible for approximately 2 to 3 percent of global carbon emissions, a figure that continues to rise with increasing travel.
Production Challenges: BioSAF and e-SAF
SAFs can be derived from two main sources: biological materials, such as agricultural waste and used cooking oils (known as bioSAF), and synthetic fuels created from hydrogen and captured CO2 (e-SAF). However, the report highlights that the limitations of bioSAF stem from the finite availability of sustainable biomass. Competition for land and water resources, along with the need for food production, significantly restricts the amount of biomass that can be diverted to aviation fuel. “Increasing biofuel production could also exacerbate pressures on biodiversity and water resources,” the report warns.
Conversely, e-SAF production faces challenges related to the availability of electricity. To replace the current global consumption of kerosene with synthetic fuel, it would require an astonishing 10,000 terawatt-hours of electricity per year—around one-third of the total global electricity output. To illustrate, a single transatlantic flight would necessitate approximately 720 kg of dry biomass per passenger to generate the equivalent bioSAF.
Future Projections and Necessary Adjustments
According to projections from the Air Transport Action Group, even with ambitious SAF deployment, aviation could still be consuming a similar volume of fossil kerosene by 2050 as it does today. “Even in the most optimistic scenarios, we do not see a significant reduction in emissions,” stated Loïc Bonifacio, vice-president of Aéro Décarbo and co-author of the report. Emissions are expected to peak around 2030, tapering off to only a 9 percent reduction from current levels by mid-century—far from the targets set by the Paris Agreement.
The authors of the report assert that a viable path forward necessitates a reduction in air travel as SAF production ramps up. “To mitigate emissions, we need to decrease fossil fuel consumption,” Bonifacio explained. “While we await the large-scale adoption of SAFs, air traffic must contract.” The report suggests that achieving a trajectory compatible with limiting global warming to 1.7 degrees Celsius would require at least a 15 percent reduction in air travel within the next five years, reverting to levels seen in the 2010s. A more ambitious target of 1.5 degrees would necessitate a drastic 60 percent cut by 2035.
Rethinking Aviation’s Role in a Sustainable Future
The implications of these findings are profound. The report posits that discussions around the future of aviation must consider sustainable usage, with a suggested global cap of about 1,000 km of air travel per person annually. In 2018, only 11 percent of the global population engaged in air travel, with a mere 1 percent contributing to half of aviation’s emissions.
Moderating growth does not inherently spell the end of affordable air travel; however, it calls for a reevaluation of airport expansions, particularly in affluent nations where flying is already commonplace. “We do not dictate specific measures, but it is reasonable to scrutinise airport expansion projects and promotions for air travel in light of climate change and geopolitical issues surrounding fossil fuel supplies,” Bonifacio asserted.
Why it Matters
The urgency of addressing aviation emissions cannot be overstated. As global air traffic continues to rise, the aviation sector must urgently confront its reliance on fossil fuels. The findings of this analysis emphasise that without a concerted effort to reduce consumption and innovate sustainable technologies at scale, the industry risks jeopardising the planet’s climate goals. A shift towards sustainable aviation is possible, but it will require a radical rethinking of both our travel habits and the policies that govern them.
