The European Commission published new findings on Tuesday (24 November) that confirm aviation’s non-CO2 climate impact is substantial, as the EU executive mulls how to regulate plane travel in the decades to come.
Carbon dioxide has the most quantifiable warming effect on our planet but other greenhouse gases, although less abundant, play a role. In aviation, the altitude planes fly at has complicated research into what impact nitrogen oxide (NOx), soot and more can have.
A new comprehensive study conducted by the European Aviation Safety Agency (EASA) for the Commission looks at how gases like NOx can be tackled by EU policies, although the authors insist “several uncertainties remain and new ones have emerged”.
EASA’s experts say that new climate modelling techniques suggest that “aviation emissions are currently warming the climate at approximately three times the rate of that associated with aviation CO2 emissions alone.”
That means that non-CO2 is up to two times worse for the climate than carbon dioxide alone.
How all these various emissions interact in the atmosphere, especially at altitude, requires more research, according to the Commission. But it is against that backdrop that new policies are already starting to be designed.
Currently, only carbon dioxide emissions from planes that fly intra-EU routes are included under the bloc’s carbon market, the emissions trading system (ETS). Next year the Commission will update the legislation that underpins it.
The study suggests that a monetary charge could be levied on NOx emissions and that they could be folded into the ETS in order to “incentivise manufacturers and airlines to reduce these emissions”.
However, the Commission insists that more time is needed for research and to establish what the right price would need to be. That is why the study estimates that it would take between five and eight years to implement a charge.
Jo Dardenne, aviation manager with clean mobility group Transport & Environment said that “the EU should lead by ensuring air traffic doesn’t bounce back to pre-COVID levels while getting planes to fly smarter routes and use e-fuels from renewable sources.”
She added that “the European Commission was first tasked with addressing the non-CO2 emissions of flying in 2008. It shouldn’t waste any more time in implementing the solutions that are available today.”
An additional “climate charge” could also be deployed, although EASA’s experts warn it would likely be more complicated to implement, given the lack of common international standards for pricing the full climate cost of a flight and the “significant research” needed.
To cut non-CO2 emissions at source, the EU executive’s experts support a fuel-blending target, which would increase the use of sustainable aviation fuels (SAFs). SAFs are greener and contain less particulate matter and sulphur emissions than regular kerosene.
Green MEP Ciarán Cuffe told EURACTIV that “the fuels must be truly sustainable and we cannot repeat the mistakes of the past as was the case with land-based biofuels”, adding that the timeframes suggested by the study are unrealistic.
“These measures are needed urgently to address the environmental cost of aviation, but also to further incentivise modal shift,” the Irish lawmaker said, adding that the “climate charge” will be required if energy taxation rules are not revised sufficiently.
Early next year, the Commission is expected to publish its ‘ReFuelEU’ initiative, which is aimed at boosting SAF’s current meagre share of fuel demand and which could, reportedly, already include a blending mandate.
Another emissions-busting measure under consideration would involve tweaks to air traffic management (ATM) so that flight paths “avoid ice-supersaturated areas and other regions considered climate-sensitive”. There is currently no obligation or incentive for airlines to avoid them.
Aircraft contrails can reflect radiated heat back towards Earth, increasing surface warming. The study insists that “an enhanced capability to predict accurately the formation of persistent contrails” is needed for the idea to work well.
According to the EASA study, Japanese ATM diverted just 1.7% of flights and recorded a reduction in contrail impact of nearly 60%. However, it added that “the findings may not transfer to the European context”.
The Commission recently unveiled its updated Single European Sky proposal, which promises to update decades-old flight paths and a 10% emissions cut, provided by reduced fuel burn.
Transport Commissioner Adina Vălean confirmed in a written answer to MEPs last month that the “up to 10%” cut includes all greenhouse gases, after Green lawmakers raised doubts about the accuracy of the emissions reductions on offer.
[Edited by Benjamin Fox]