Airlines and airports have opposed measures to combat global warming caused by contrails from aircraft that evidence suggests account for more than half of the aviation industry’s climate impact, new documents reveal.
Industry argued in government submissions that the science was not “robust” enough to justify reduction targets for these non-CO2 emissions Scientists say the climate impact of vapor trails, or contrails, has been known for more than two decades, with one accusing the industry of a “typical climate denial strategy.”
While carbon emissions from jet engines contribute to global warming, research suggests that contrails formed when water vapor and soot particles transform into ice crystals have an even bigger impact. These man-made clouds trap heat in the atmosphere that would otherwise escape into space.
The contrail lobbying in the documents obtained by openDemocracy highlights the lack of consensus among airline executives, scientists, and carbon offsetting websites about the exact climate impact of flying. It means that people who want to offset the environmental impact of their flights get significantly different prices.
The Intergovernmental Panel on Climate Change estimated in a 1999 special report that aviation’s historical impact on climate was two to four times greater than that of its CO2 emissions alone. A 2020 study conducted by the EU also reported no CO2 Aircraft emissions, made up mostly of contrails, warm the planet about twice as much as the carbon dioxide released by planes, but he acknowledged there were “significant uncertainties.”
Photograph: Rob Matthews/Alamy
Piers Forster, professor of climate physics at the University of Leeds and a member of the Committee on Climate Change, which advises the government on emissions targets, said: “Industry must not hide behind uncertainty and must act to rapidly reduce both its CO2 and not CO2 effects.”
Milan Klöwer, a climate scientist at the Massachusetts Institute of Technology, said airlines were adopting a “typical climate denial strategy” by exaggerating the level of uncertainty about non-CO gases.2 effects. He said: “Even in the best of cases, they almost double the effect of CO2 emissions on the climate.
The aviation industry said in submissions to the 2021 government consultation for its “jet zero” strategy of achieving net zero carbon emissions that more research was required into the impact of non-CO gases.2 impacts
Airlines UK, the trade body for UK-registered airlines, said: “The science around [non-CO2 impacts] it is not yet robust enough to form reduction targets.” Ryanair and Wizz Air said it was too soon to formulate and implement policies to mitigate the impact of contrails.
Sustainable Aviation, which brings together airlines, airports and other industry players, said there were projects looking at ways to reduce non-CO gases.2 emissions, but it was too early for regulation.
It said: “Given the complexity of operations without CO2 impacts, developing science, and a wide range of impacts, we don’t think no CO2 emissions must be included in the information directed to the consumer”.
Introducing the Jet Zero strategy last year, the government said sustainable aviation fuel was expected to mitigate the climate impact of contrails.
Airlines tend to ignore non-CO2 effects on schemes to offset flight emissions. The official tool of the International Civil Aviation Organization to calculate emissions also does not include contrails in its methodology.
BA’s emissions calculator says that a one-way flight from London Heathrow to New York emits 348kg of CO2E (carbon dioxide equivalent) and charges £3.97 for compensation.
But Atmosfair, a German non-profit organization that supports decarbonising flights, estimates that the same trip on a Boeing 777-200, a type of aircraft used by BA, emits 896kg and charges £18.37 for the compensation. Atmosfair emissions include CO equivalent2 emissions of 587 kg, which is largely for contrails.
A Sustainable Aviation spokesperson said: “UK aviation recognizes that no CO2 the impacts need to be better understood and addressed, and supports future research. That’s why we welcomed the inclusion of non-CO2 monitoring solutions in the EU Emissions Trading Scheme [and] why testing of aircraft powered by sustainable aviation fuels will include non-CO monitoring2 benefits.”
Rob Bryher, aviation campaigner at climate charity Possible, said: “These documents show that airlines cannot be trusted to decarbonise on their own. Demand management solutions, such as a frequent flyer tax, the introduction of fuel taxes, carbon pricing or airport capacity management, will be crucial”.
The Department for Transport said: “Our jet zero strategy confirmed our goal of tackling the problem of no CO2 impacts of aviation, by developing our understanding of its impact and potential solutions, and the UK is one of the leading countries working to address this issue.”