Despite protests from the aviation sector, the European Union is going ahead with plans to make European airlines report the impact of the vapour trails left in the atmosphere by aircraft.
The new rules, discussed in spring 2024 and slated for 2025, were formally adopted by European delegates at the end of August in a closed session. Airlines had argued against the obligation to report, using the idea that not enough is known about so-called “non-CO2” emissions to justify a monitoring or reporting regime. But the EU Commission took this lack of current knowledge as all the more reason to impose the new requirements, saying that more could be learnt about the emissions the more they were reported.
Contrails could cause worse warming than CO2 emissions
The Commission recognised “inherent uncertainties” around the effects of the contrails, which are formed from ice crystals and made up of substances such as nitrogen oxides (NOx) and black carbon that are known to damage the climate by trapping heat in high cloud cover. But the executive body said, “Studies have shown that the uncertainty in these effects is not a sufficient reason to avoid action.”
The studies referred to have already indicated that contrails could be responsible for over half (57%) of global warming effects from aviation, a sector estimated to be the cause of 2% of worldwide CO2 emissions. A 2019 research paper meanwhile, forecasts that radiative effects from contrails could triple by 2050.
Gathering more data thanks to the new regulations could help scientists to understand how better to reduce global warming, Imperial College London has said. For example, this could include pollution reduction of around 60% in some places, if planes were rerouted to avoid the cold and humid conditions and high altitudes that promote contrail formation.
Long-haul flights’ impact won’t be measured until 2027
Though the EU largely dismissed airlines protests about having to estimate and report contrail effects, the carriers did achieve one concession. For next year, airlines will only need to report on contrails on flights between airports in the European Economic Area, which is composed of the EU, Iceland, Norway and Switzerland. The full new reporting regime, covering all flights in and out of the EU, will not come into effect until 2027.
Environmentalists have expressed disappointment about the postponement for long-haul aviation, which Krisztina Hencz, policy manager at Transport & Environment, said amounted to “preferential treatment”, accusing airlines of lobbying to “undermine action and research on non-CO2”.
