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As the aviation industry grapples with its environmental impact, recent research indicates that sustainable aviation fuels (SAFs) may not be the silver bullet required to curb carbon emissions. Despite being considered the most viable alternative to fossil kerosene, experts assert that the production of SAFs cannot keep pace with the anticipated growth in air traffic, raising concerns about the sector’s sustainability efforts.
The Limitations of Sustainable Aviation Fuels
A comprehensive report from Aéro Décarbo, an association comprised of aeronautics professionals, alongside the non-profit think tank The Shift Project, reveals that transitioning to SAFs will demand an astonishing one third of the world’s current electricity output. This staggering figure underscores the enormity of the challenge at hand. The study points out that even under the most optimistic scenarios regarding aircraft efficiency and the adoption of SAFs, significant reductions in aviation emissions are unlikely by 2050.
Current estimates suggest that aviation contributes between 2% and 3% of global CO2 emissions, a figure that is steadily climbing. The industry is noted for its difficulty in achieving decarbonisation, with SAFs derived from either bio-sources or renewable electricity potentially holding the key to a cleaner future. Bio-SAFs are produced from organic materials such as agricultural waste and used cooking oils, while e-SAFs are synthesised from hydrogen and captured carbon dioxide through electricity. However, the report highlights that the core issue is not whether these fuels are effective, but rather whether they can be produced in sufficient quantities to meet rising demand.
The Production Conundrum
The limitations of biofuel production are stark. With finite availability of sustainable biomass, factors such as land use, water resources, and competition with food supply restrict the amount of material that can be allocated for aviation fuel. The report cautions that expanding biofuel production could inadvertently exacerbate pressures on biodiversity and water systems.
Conversely, the challenge for e-SAFs lies in the availability of electricity. According to Loïc Bonifacio, vice-president of Aéro Décarbo and one of the report’s co-authors, meeting the current global kerosene consumption with synthetic fuel would necessitate approximately 10,000 terawatt-hours of electricity annually. This is a staggering demand, and even optimistic projections for SAF deployment suggest that aviation will still rely on fossil kerosene to a significant extent by 2050.
Bonifacio emphasises that even under ambitious deployment scenarios, aviation’s fossil fuel consumption is projected to remain largely unchanged. “The growth of traffic is too high for technology to progress at the necessary pace,” he explained, suggesting that emissions will peak around 2030, only to drop to a level approximately 9% below current figures by mid-century—far from the targets set by the Paris Agreement.
The Path Forward: Rethinking Air Traffic Growth
The report proposes a radical approach to mitigate emissions: a reduction in air traffic while SAF production scales up. Bonifacio asserts that to effectively lower emissions, the consumption of fossil fuels must diminish, which is contingent upon the availability of SAFs in substantial volumes. He advocates for a strategic decline in air traffic until SAF capacity can adequately support future demands.
To align with climate goals that aim to restrict global warming to 1.7 degrees Celsius, air traffic would need to decrease by at least 15% over the next five years—returning to levels seen in the 2010s. A more stringent target of 1.5 degrees would necessitate a drastic 60% reduction by 2035. This underscores the importance of evaluating our collective use of aviation and the regulations needed to manage it.
In 2018, merely 11% of the global population engaged in air travel, with a mere 1% responsible for half of commercial aviation’s emissions. The authors propose that moderating growth does not equate to an end to affordable travel. Instead, it calls for a halt to airport expansions, particularly in affluent nations where air travel is already common, until SAF production can adequately support increased air traffic.
Why it Matters
The findings of this report highlight a critical juncture for the aviation industry. As the world faces mounting pressures from climate change, the challenge of decarbonising air travel must be addressed with urgency and pragmatism. Without a clear strategy to moderate growth in conjunction with enhanced SAF production, the aviation sector risks falling far short of the ambitious climate targets necessary for a sustainable future. The conversation surrounding air travel, its environmental impact, and the feasibility of sustainable alternatives must be prioritised to ensure that we do not jeopardise the planet’s future in our pursuit of connectivity.
