In addition to CO₂, aviation affects the climate through other emissions and atmospheric processes, such as the formation of ozone and contrail cirrus. Although these non-CO₂ effects account for about 2/3 of aviation's total climate impact, they have not been regulated in the past.

According to Article 30(4) of the EU ETS Directive, ‘the Commission shall present (before January 2020) an updated analysis of the non-CO₂ effects of aviation, accompanied, where appropriate, by a proposal on how best to address these effects.’ In light of this, the EU Commission commissioned a study to EASA.

In this project, the corresponding EASA report to the European Commission was critically reviewed.