Implementing an Eu Agreement on Monitoring, Reporting and Verification of Non-CO2 Climate Effects in Aviation

Abstract

The EU Emissions Trading System for aviation (EU ETS) only considers CO2 emissions. Consequently, approximately two-thirds of aviation's climate impact, caused by non-CO2 effects, are not included. The EU trilogue from 2022 has agreed to revise the EU ETS. From January 1, 2025, non-CO2 aviation climate effects shall be covered by a monitoring, reporting and verification (MRV) system as a potential first step towards the full integration into the EU ETS. The non-CO2 MRV is essential to track progress towards climate-neutral aviation, incentivize mitigation actions, and demonstrate compliance with international agreements such as the Paris Agreement. However, the inclusion of non-CO2 effects is controversial. There are several concerns: i) High uncertainties in non-CO2 climate effects might lead to adverse incentives ii) CO2 equivalents (CO2e) can be calculated at various levels of detail by applying different models, climate metrics and time horizons. iii) Administrative and technical challengers, including data requirements, availability and flows, might create an additional effort for the involved parties. We discuss and analyze these issues to identify options for including aviation non-CO2 effects into a political framework. The non-CO2 MRV is designed for continuous development, allowing new scientific knowledge, new technologies and future fuels to be included into the system. This enables a gradua lreduction in uncertainties. We present the scientific inputs for the legal draft of a non-CO2 MRV system, which supports the process towards an EU-wide MRV system and its operationalization. Our findings are derived from research projects on behalf of the German Environmental Agency and current activities at EU commission level as part of an EU-tender. This includes non-CO2 monitoring and reporting by aircraft operators, verification by independent third parties (accredited verification bodies) and emission report approval by the state competent authority. The research involves the analysis of suitable climate metrics and climate models for the CO2e calculation of single flights, the definition of the data requirements for its application and the engagement with relevant stakeholders on provision of this data. We propose a two-fold approach for CO2e calculation, a climatological approach that reduces the MRV effort and a weather-based approach as the full potential solution. The solution on a higher complexity level can increase the accuracy of the results and offers aircraft operators more incentives for climate impact mitigation. However, the increased administrative burden must be taken into account to maintain acceptance among all stakeholders. Our two-fold approach is therefore a trade-off between scientific accuracy and climate mitigation potential on the one hand and administrative effort and operational feasibility on the other. For both options, we define a minimum data set, a possible extended list of data and propose default values for data gaps required for technical issues or confidentiality. Uncertainties are an inherent part of all aspects of CO2e calculation and will remain. But their mere existence should not be a reason to postpone mitigation action or to prevent the implementation of MRV. Rather, the development of an MRV that can be improved based on novel academic insights provides a vehicle to reduce these uncertainties. There is also a need to address uncertainties by appropriate validation and evaluation in order to improve understanding and quantification of their risks and impacts.