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The aviation industry stands at a crossroads, grappling with the urgent need for decarbonisation amid escalating traffic growth. While sustainable aviation fuels (SAFs) are heralded as a promising alternative to traditional fossil kerosene, a recent report unveils a stark reality: the pace and scale of SAF production may fall woefully short of what is required to mitigate rising carbon emissions in the coming decades.
The Challenge of Sustainable Aviation Fuels
Sustainable aviation fuels, including bioSAF derived from organic materials and e-SAF produced using renewable electricity, have been enthusiastically embraced by airlines and manufacturers. However, experts warn that the production of these fuels cannot keep pace with the soaring demand for air travel. According to a study released by Aéro Décarbo, an association of aerospace professionals, in collaboration with the non-profit think tank The Shift Project, even under the most optimistic scenarios, aviation emissions are unlikely to see a significant decline by 2050.
The report highlights that aviation currently contributes approximately 2 to 3 per cent of global CO2 emissions, a figure that continues to rise in tandem with increasing air traffic. The anticipated growth of the industry raises pressing questions about the sustainability of current practices and the feasibility of transitioning to greener alternatives.
BioSAF and e-SAF: Potential and Limitations
The promise of bioSAF lies in its derivation from non-fossil sources, such as agricultural waste and used cooking oil. Unfortunately, the availability of sustainable biomass is limited by factors like land use, water resources, and competition with food production, as highlighted in the report. The potential expansion of biofuel production might also exacerbate challenges related to biodiversity and water scarcity.
On the other hand, e-SAF faces an equally formidable hurdle: the sheer volume of electricity required for its production. To replace the current global consumption of kerosene with synthetic fuel, approximately 10,000 terawatt-hours of electricity per year would be necessary. This staggering figure represents about one-third of the world’s current electricity output. For context, a single transatlantic flight demands a significant amount of biomass—around 720kg per passenger—just to produce the equivalent bioSAF.
The Path Forward: A Call for Reduced Air Traffic
The Aéro Décarbo report concludes that the only viable route towards genuine emissions reduction involves a decrease in air traffic until SAF production capacity can catch up. Loïc Bonifacio, vice-president of Aéro Décarbo and co-author of the study, stated, “To reduce emissions, we need to reduce fossil fuel consumption. However, as long as SAFs aren’t available in sufficient quantities, air traffic must decrease.”
To align with the goals of the Paris Agreement, a reduction in air traffic of at least 15 per cent over the next five years is necessary to adhere to a 1.7-degree warming limit, with an even steeper 60 per cent reduction required to meet a 1.5-degree trajectory by 2035. This would effectively return global air travel to levels seen in the 2010s.
Rethinking Aviation Growth
The authors of the report argue that moderating growth in air travel need not eliminate affordable access to flying. However, it necessitates a critical reevaluation of airport expansions, particularly in affluent nations where air travel is already prevalent. Bonifacio suggests that discussions around sustainable aviation must consider the extent of global air travel and the regulations that should govern it.
In a more sustainable future, the ideal scenario might involve limiting individual air travel to around 1,000 kilometres per year per person globally. Notably, in 2018, only 11 per cent of the world’s population took a flight, with a mere 1 per cent responsible for half of all aviation emissions.
Why it Matters
As the aviation industry seeks to balance growth with environmental responsibility, the findings of this report underscore a fundamental challenge: the transition to sustainable aviation fuels is fraught with obstacles that require immediate and concerted action. With climate change escalating, a collective commitment to reducing air traffic and rethinking our aviation practices has never been more pressing. Without significant changes, the industry’s reliance on fossil fuels may persist, jeopardising global climate goals and our planet’s future.
