Cloud formation by aircraft also contributes to climate change. This is not taken into account enough (Photo: Fr. Daniel Ciucci on Unsplash).
Cloud formation by aircraft also contributes to climate change. (Photo: Fr. Daniel Ciucci / Unsplash).

The UN’s plan to reduce aviation’s impact on the climate is virtually meaningless, asserts TU Delft aviation expert Joris Melkert and his colleagues in Nature Communications.

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The climate impact of aviation must be reined in. The ICAO (International Civil Aviation Organization), the aviation agency of the United Nations, does not pull its punches. In the accord that it drew up in 2016 in the wake of the Paris Climate Agreement, the amount of CO2 that is emitted by the aviation industry from 2020 onwards may not increase. In conjunction with this target, a special mechanism was established: CORSIA, Carbon Offsetting and Reduction Scheme for International Aviation.

‘It is is a poor compromise’

“The 2016 accord is a poor compromise,” says aviation expert Joris Melkert of the Faculty of Aerospace Engineering. “We need to reduce emissions, not continue at the same level.”

The aviation industry will thus not help limit global warming to 2 degrees by 2100, let alone the desired 1.5 degrees, says Melkert. He and his German, British and Swedish colleagues expressed their concerns in the scientific journal Nature Communications this week.

In their article, Evaluating the climate impact of aviation emission scenarios towards the Paris Agreement including COVID-19 effects the researchers calculated CORSIA’s impact of and that of a whole range of other plans brought forward over the last few years to limit global warming. They took the expected increase in air traffic after the corona pandemic into account. None of the current plans is in line with the Paris Agreement.

One of the reasons is the fact that the effects of the aviation industry on the climate is far more wide-ranging than only carbon dioxide. Aeroplanes stimulate cloud formation and emit nitrogen dioxide, sulphur dioxide and methane. These are all effects that exacerbate global warming and the ICAO and the think tanks that advise on aviation and the climate do not sufficiently take these into account. The effect of all these additional factors on the climate may still be uncertain, but that is not a reason to push it aside, says Melkert.

‘Our article is a call to action’

“Our article is a call to action,” says Melkert. He believes that the aviation industry needs to adopt many more methods to reduce its impact on the climate. “This problem can be solved, but then we need to move hard and fast.” Among the actions that should be taken, the researchers cite the need to put more effort into the development of sustainable fuels. “But it would also help if aeroplanes fly more slowly and lower,” adds the aviation expert. “Low flying aircraft create less cloud formation.”

ACARE (Advisory Council for Aviation Research and innovation in Europe), the European think tank, will come up with updated advice on reducing the impact on the climate by the end of the year. This think tank presented the Flightpath 2050 Europe’s Vision for Aviation report in 2011. Melkert says that “It is the most cited of the scientific articles about aviation and climate change. It is a benchmark arcticle.” Nevertheless, some of the scenarios do not go far enough, assert Melkert and his colleagues. “We hope that they take our recommendations seriously.”