The European Commission 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 study builds on the latest scientific knowledge and presents a fresh analysis of the main climate impacts associated with air traffic, beyond carbon dioxide (CO2) emissions. CO2 emissions from aviation have been addressed under the EU Emission Trading System since 2012, but non-CO2 impacts have not been specifically addressed by EU policies so far. However, the report acknowledges that a number of measures already in place also contribute to reducing the climate impacts of non-CO2 aviation emissions.
The work was conducted by a project team assembled by EASA, comprising the most renowned experts in the field from the EU, Norway and UK. The study reflects the views of its scientific authors and does not constitute an official opinion of the Commission. A short Staff Working Document from the Commission services accompanies the study.
The significance of combined non-CO2 climate impacts from aviation activities, previously estimated to be at least as important as those of CO2 alone, is fully confirmed by the report.
The report calls for further reflection on how to best address non-CO2 climate impacts, which could inform the possible development of future policies on the full impact of aviation on the climate. Doing so would contribute to the EU's climate objectives and the Paris Agreement, alongside existing actions to reduce CO2 emissions. Such measures would also result in improvements to local air quality.
The report examines additional policy options to address the non-CO2 climate impacts of aviation. These are divided into three categories: financial/market-related, fuel and air traffic management (ATM).
Unlike CO2 impacts, which directly correlate to the amount of fuel burned, the complexity of measuring non-CO2 climate impacts - and the uncertainty regarding trade-offs between the various impacts - makes targeted policy development in this area more challenging.
The policy options assessed in the study are divided into three categories: financial/market-related, fuel and air traffic management (ATM). The options could co-exist.
1) - The financial measures consist of a levy on aircraft NOx emissions and/or the inclusion of such emissions under the EU ETS. This would incentivise manufacturers and airlines to reduce these emissions, while taking account of associated trade-offs.
Outstanding research obstacles to making the policies implementable include:
Given these outstanding research issues, the study concludes that these measures could be implemented in the mid-term, i.e. 5 to 8 years.
2) - The fuel-related measures are about the reduction of aromatics in fuel (leading to cleaner fuel burn and reduced non-volatile Particulate Matter [nvPM] emissions) and the mandatory use of Sustainable Aviation Fuels (SAF). Both measures target the emission of soot particulates and contrail cirrus clouds. Reducing aromatics content would require fuel producers to adapt their production processes and a system to monitor the aromatics content of fuels. Given the set of research issues to be addressed according to the experts, the measure could potentially be implemented in the mid- (i.e. 5 to 8 years) to long- term (i.e. 8+ years). The mandatory use of SAFs, could be implemented through an EU blending mandate specifying that a certain percentage of the total jet fuel sold over a set time period would have to be SAF. If well designed, this should lead to simultaneous reductions in CO2, nvPM and sulphur emissions (though not NOx emissions).
The experts consider that if related outstanding research issues linked to this measure are resolved, the measure could potentially be implemented in the short- (i.e. 2 to 5 years) to mid-term (i.e. 5 to 8 years).
The Commission is already assessing options to boost the production and uptake of Sustainable Aviation Fuels (SAF) and plans to propose a policy initiative on this shortly. The IA will duly address the non-CO2 dimension of SAFs.
3) - The measures in the ATM category are avoidance of ice-supersaturated areas and a climate charge. Optimizing flight trajectories to avoid climate-sensitive regions would reduce the formation of contrail-cirrus clouds, while the climate charge would address all non-CO2 effects (NOx, water vapour, soot, sulphates, contrails).
As there is a series of research issues that would first need to be addressed, the avoidance of ice-supersaturated areas measure could, according to experts, potentially be implemented in the midterm, i.e. 5-8 years. Regarding the climate charge, the experts deem that given the broader nature of the measure and the associated research needed, it could potentially be implemented in the long-term, i.e. 8+ years.