Boris Johnson’s “jet zero” goal of a commercial transatlantic flight producing no carbon emissions by 2025 is a “gimmick”, according to experts, who say technology alone cannot solve the impact of global aviation on the climate crisis. Such a flight would not be impossible, the experts said, but could only be a one-off and would encourage the view that other measures such as taxing jet fuel and frequent fliers were not needed to tackle aviation’s carbon problem. The jet zero technology idea was part of Johnson’s 10-point “green industrial revolution” plan launched last week. But experts called jet zero “severely underfunded”, and pointed out that the government would not begin consulting on a strategy to decarbonise aviation until next year. The UK has also not demanded green action from airlines in return for coronavirus bailouts, unlike France. The pandemic has halved passenger numbers but the industry expects them to recover by 2024. However, the experts also praised the UK for taking some action, given that only a few countries are even beginning to tackle an issue seen as one of the most difficult climate challenges. The aviation industry says more efficient planes and buying millions of tonnes of carbon offsets can compensate for big future increases in passenger numbers. Independent experts say new taxes to deter flying are vital, and agree with the aviation industry that green jet fuels are needed too. These exist and could power long-haul flights, but are currently expensive. Long-haul electric or hydrogen planes are unlikely before the middle of the century, if ever, by which time emissions should already have been cut to zero. “We will position the UK at the forefront of aviation,” says Johnson’s green plan. “British innovation will unlock the world of sustainable fuels [to] allow the opportunity of global travel whilst also safeguarding our planet.” The jet zero council, which brings together ministers and industry chief executives, has met once, in July. The prime minister told the group he wanted “ambitious goals for aviation, such as the first zero-emission commercial transatlantic passenger flight by 2025”, according to published minutes. Johnson’s green plan said a £15m competition to support the production of sustainable aviation fuels (SAF) in the UK would be held in 2021, alongside a consultation on introducing a requirement to blend green fuels into kerosene, “possibly starting in 2025”. Another £15m is to be spent on a 12-month “fly zero” study examining zero-emission aircraft that could fly from 2030. “I guess enough [SAF] could be produced to fuel a single, one-off operation in 2025 but that would of course just be a gimmick – anything beyond that would be very much unrealistic,” said Chris Lyle, the chief executive of the Air Transport Economics consultancy and a former official at the International Civil Aviation Organization, a UN agency. Regulations would also have to be changed to allow 100% SAF to be used. Dan Rutherford, a programme director the International Council on Clean Transportation, said: “It would be like a crash space programme to plant a flag on the moon, without knowing when you’d go back again.” Stefan Gössling, a professor at Linnaeus University in Sweden, said such a flight might even be technically feasible by 2022, but would reinforce the industry’s suggestion that “we will resolve the problem [with technology] – keep flying”. Lyle said: “Technology alone can in no way get close to solving aviation’s emissions problems.” The omission from the UK plans of other measures such as taxes was “emphatically a mistake”, he said. The lack of tax on jet fuel gives aviation an unfair advantage against train and coach travel, Lyle added. Gössling said: “The challenge of greening aviation is massive. I cannot see any other option than non-biogenic synthetic fuels.” These are fuels made using green electricity to combine CO2 and hydrogen. Biofuels made from crops can have large carbon footprints and compete with food production. Producing jet fuel from non-recyclable waste is another possibility. Gössling said a carbon tax on kerosene was needed to pay for the climate damage it caused and deter the growth in air travel, adding that such a tax would also make green synthetic fuels more cost-competitive. He said a frequent flyer tax was unlikely to curb demand among the wealthy “super-emitters” who cause half of all emissions, but could help fund synthetic fuel development and other research. According to Rutherford, the UK’s jet zero goals are “aggressive” but also “severely underfunded”. He said the latest research estimated commercial SAF plants were likely to cost £600m–£700m while new conventional aircraft cost at least $10bn (£7.5bn) to develop. “Fifteen-million-pound investments are something that could excite academics but aren’t going to move the needle in any significant way on electric or hydrogen aircraft, for example,” Rutherford said. Tim Johnson, the director of the Aviation Environment Federation, who sits on the jet zero council, said: “A few funding initiatives plus lots of ambition won’t get the industry anywhere near net zero.” He said regulation and taxes were needed, as well as the inclusion of international aviation emissions in the national carbon plans submitted to the UN. Currently they are exempt. Removing the exemption, said Lyle, “would give individual countries more incentive to do something about them”. Lyle was dismissive of the UN aviation body’s efforts to cut emissions, saying: “The ICAO is still studying the ‘feasibility’ of an aspirational long-term emissions goal for aviation, which it was given a mandate for by its assembly in 2010.” Gössling said the UK’s aviation goals placed it among the leading nations, but only because ambition was absent in most countries. A spokesman for the IATA, which represents the airlines industry, said: “The UK is a leading country when it comes to action on emissions.” Gössling said rather than a single transatlantic zero-emissions flight in 2025, a better UK goal would be to ensure that by 2025, 10% of all fuels used will come from renewable sources, or even better, will be non-biogenic synthetic fuels. A few other nations including France already have such fuel mandates. Norway’s is the most ambitious, requiring 30% from renewable sources by 2030. But airlines, such as those in the US, oppose SAF mandate proposals. “The timing needs to be realistic,” said the IATA spokesman. “It will take time to scale up production. It usually takes three to four years to build a plant, so I think a five-year window [to 2025] to get supply up and running is necessary.” He added: “We believe we can solve the problem of CO2 emissions with technology. There is a growing body of research that says we have clear pathways to achieving our 2050 goals of a 50% reduction in emissions from 2005 levels and quite possibly zero emissions from 2060-65, through the scaling up of SAF, and future technology like electric and hydrogen-powered flight, from 2035. Offsetting is also available but we currently see this as a short-term measure while technology is scaled up.” Sustainable Aviation, a UK industry group, has set out a road map to net zero emissions that allows for a 70% growth in passengers by 2050 and relies heavily on buying carbon offsets elsewhere. Andy Jefferson, the group’s programme director, said there was no “silver bullet” for dealing with aviation carbon emissions but there was clear evidence that taxes had no environmental benefits and were the least effective way to reduce emissions. “With the right [government] support, we do not see the need to impose additional demand reduction measures,” he said. Tim Johnson said any financial assistance to aviation from taxpayers should come with the requirement of action: “Talk of incentives and funding is misplaced when the industry is only offering voluntary commitments in return. Technology aspirations shouldn’t provide continued cover for the industry to get away with no effective accountability, tax or regulation on its emissions.” “Jet zero isn’t a substitute for the government setting out the policies required to set the UK aviation sector on a trajectory to net zero emissions,” said Johnson. “A cleaner and leaner air travel sector will mean we need to fly less, and we shouldn’t be expanding our airports.”