Greenhouse gas emissions from air traffic even worse than expected – new EU report

Earlier this year, we calculated different ways of calculating CO₂ emissions from air transport (link), and in these news we also discussed the so-called condensation trails effect, which is additional impacts (radiative forcing) on global warming to a greater extent than just the CO₂ emitted from aircraft engines. The climate impact is exacerbated by the fact that emissions occur at high altitudes, by the formation and impact of condensation streaks, water vapor, NOx emissions, soot particles and sulfur dioxide. All these factors contribute (although some of them counteract each other) to CO₂ emissions being multiplied by at least a factor of two in order to capture the full effect… and that seemed like a reasonable assumption until now (as it was about a factor of two most of our sources in the aforementioned article). The UN’s climate panel IPCC has so far assumed that one should multiply by a factor of two or three, which also testifies to uncertainty about the subject.

But in September 2020, the EU aviation agency EASA finally released an alarming update to these additional impacts, and it now turns out that we should actually multiply emissions by a factor of three – and not just two. EASA points out that it has become wiser in the field over the last ten years.

And we listen to institutions that become wiser; we listen to the IPCC and the EU, and this means that we have to raise our estimate for aircraft compensation, from approx. 300 to 600 g CO₂ emitted per flight kilometer in economy class (See calculations in the original news on the subject (link).

On the positive side, this report means that the European Commission now recommends introducing stricter tariffs on emissions of not only CO2 in the ETS but also on other emissions, e.g. NOx. But as action in this area takes time, we continue to plant trees today!