9 December 2020: The European Commission has requested that the European Union Aviation Safety Agency (EASA) conduct an updated analysis of the non-CO₂ effects of aviation on climate change to fulfil the requirement of the EU Emissions Trading System Directive (Art. 30.4).

The report builds on the latest scientific knowledge and confirms that the impacts of non-CO2 emissions are just as significant as CO2 emissions although it is more complicated to measure these non-CO2 effects.

The study first reviews and updates the status of science on topic and associated uncertainties in regards to climate impacts. The analysis confirmed that non-CO2 impacts arise from NOx, soot, particulate matter and water vapor. Scientific understanding has evolved over the last decade, since the last studies on the topic were published in 2006 and 2008 which only focussed on NOx. The impacts are linked to net-NOx effects and contrail cirrus – but there are still significant uncertainties on the magnitude of these.

The study then looks at existing technological options that are already in place to reduce non-CO2 impacts and also analyses the tradeoffs. Finally, the study proposes policy options that help address the issue. It identifies different policy options. The first is financial: there could be a possible NOx emission charge and the inclusion on non-CO2 within the EU ETS, but for this to happen it is necessary to reduce the uncertainty on NOx and select appropriate CO2 emission metrics to select the appropriate level of the charge. This could also be applied within the SES charges scheme and is applicable for the long-term. On the fuel option, it could be accounted for via a blending mandate, but again, it is important to reduce the uncertainty and make sure that an initiative that leads to the uptake of SAF is facilitated. This could be applied to the short and mid-term. Finally, there could be a charge association to the flight trajectory as an optimisation of flights could lead to environmental benefits including a reduction of contrail formation. However, there is limited feasibility in the congested European airspace.

You can find more information here [1].