Analysts warn green air transport is impossible without cutting flight numbers

Brussels – Sustainable air transport is not feasible in the conditions and within the timeframe envisaged by the European Commission, because, as things stand, alternative or non-fossil fuels for aviation “will not be available in sufficient quantities, or quickly enough, to fully replace fossil kerosene, even under very optimistic assumptions about aircraft efficiency and technological progress.” This is according to The Shift Project, a French think tank that promotes the transition to a post-carbon economy. In a report dedicated to air transport, one thing is certain: “Commercial aviation will not be able to decarbonise in time without reducing its traffic.”

The study’s conclusion is clear: synthetic fuels for civil aviation represent the most promising technological option, but “they cannot support continued traffic growth.” Even in ambitious scenarios, production “would not scale up fast enough or in sufficient volumes.” As a result, aviation emissions “would not fall at a rate compatible with the goals of the Paris Agreement (which the EU committed to upholding, ed) unless demand for flights is reduced in the short and medium term.”

Considerations that necessarily call for a rethink and a change of course in the policies of the European Union, which, when it comes to aircraft fuels capable of meeting climate targets, is committing itself through both legislation and financial support. However, these efforts are insufficient to support a truly “green” sector. The Shift Project warns: “If global air traffic continues to grow following the current industry projections, aviation emissions would not decline by 2050.”

The unsustainability of sustainable measures

Air travel risks the paradox of unsustainable sustainable fuel sources. The French think tank’s report highlights how both bio and synthetic fuels present significant challenges. BioSAF is based on sustainable biomass: a “limited and highly contested” resource. Land availability, environmental protection, and competing uses, such as food production and material production, “all restrict how much biomass can be dedicated to aviation.” Therefore, The Shift Project warns that the expansion of biofuel production “risks creating additional pressure on biodiversity and water resources.”

As for so-called e-SAFs, fuels produced from hydrogen and captured carbon, these are not limited by land use, but require “enormous amounts of low-carbon electricity.” Therefore, “replacing all current global kerosene consumption with e-SAF would require around 10,000 TWh of electricity per year, roughly one-third of today’s global electricity production.”

Fly less, experience more

There are not many alternatives to address these challenges: either the sustainability calendar for air transport is revised, granting the sector exemptions from the 2050 targets, or incentives for alternative aircraft fuels are provided. From this point of view, the report is clear: “If airlines cannot access enough sustainable fuel to meet those targets, then overall fuel use, and therefore flight numbers, must decline.” In other words, the less alternative fuel there is, the less we can fly. 

Building on this, policy tools should “include experimentation with demand-management measures, incentive reform, supply-side regulation, and accelerated investment in sustainable transport alternatives.”