European Union Emissions Trading System (EU ETS)
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Beyond CO₂: Preparing for Aviation’s Next EU ETS Challenge
As of 1 January 2025, aircraft operators subject to the EU ETS must comply with the monitoring, reporting, and verification (MRV) of their non-CO2 effects. These effects refer to climate impacts and atmospheric changes caused by substances other than carbon dioxide, including nitrogen oxides (NOₓ), water vapour, soot particles, sulphur oxides (SOₓ), contrails and induced cirrus clouds. The requirements are set in the Monitoring and Reporting Regulation (MRR) and the EU ETS Directive. The first non-CO2 aviation effects report and its verification report are to be submitted for the first time by 31 March 2026.
According to the MRR, aircraft operators shall submit for approval a monitoring plan at the latest 4 months before they start the activities within the MRV scope, and if not possible, no later than 6 weeks after performing such activities. In other words, by mid-February 2025, operators should have already submitted a revised monitoring plan to account for non-CO2 aviation effects. In reality, the updated template for the Annual Emissions Monitoring Plan (AEMP), provided by the Commission, that includes these provisions was published on 26/02/2025, making it impossible to comply with the MRR requirement. However, operators are still required to submit a revised AEMP as soon as possible. Competent Authorities have set deadlines to ensure smooth compliance, for example, the German Emissions Trading Authority (DEHSt) has required the submission of AEMPs by 06/06/2025.
If an aircraft operator has not submitted a revised AEMP, it is recommended that they contact their Competent Authority to ensure common understanding on an acceptable timeframe to do so.
When updating the AEMP, aircraft operators will need to add the following information:
-If not, the aircraft operator has no MRV obligation for non-CO2 aviation effects.
-For 2025 and 2026, operators can choose the reporting scope among:
-Reduced geographical scope aligned with the EU ETS reduced scope (intra-EEA flights, flights from the EEA to Switzerland and the United Kingdom)
-Full geographical scope (all flights departing from or arriving in the EEA)
-In-between geographical scope (reduced geographical scope + other defined routes).
The selected option must remain consistent throughout the reporting year. If a different scope is chosen for the following year, the AEMP must be updated accordingly. From 2027 onwards, however, all operators will be required to report using the full geographical scope.
For 2025 MRV, the only approved IT tool that can be used is the Non-CO2 Aviation Effects Tracking System (NEATS), provided by the Commission.
For upcoming years, the operator can choose between NEATS, their own, a third-party IT tool, or a combination of NEATS and these other tools. However, conditions apply, for example, if a tool other than NEATS is used, the Numerical Weather Prediction (NWP) model and weather data used must be at a minimum the same as in NEATS. In addition, the IT tool must be approved by the Commission before it can be included in the monitoring plan.
–Method D: available only for small emitters as defined in Article 55(1) of the MRR, and whose status must be reassessed annually, i.e., considering the EU ETS full scope, aircraft operators operating:
fewer than 243 flights per period for 3 consecutive 4-month periods, or
flights with total annual emissions lower than 25 000 tCO2 per year.
-Method C: mandatory for all aircraft operators which are not small emitters.
-Combination of both methods: available only for small emitters, who can use different methods for different aircraft types.
-Aircraft operators can opt to provide only flight information (call sign, UTC flight date and time, origin and destination airport codes) as primary data, and hence, the non-CO2 effects will be calculated automatically using secondary data (available in NEATS).
This selection is not linked to the methodology used; all aircraft operators can opt to provide only flight information as primary data.
-If the aircraft operator opts to provide more than just flight information as primary data, they must indicate which parameters and a description of the source and procedures for determining each of them, along with data uncertainty assessments.
In April 2025, the European Commission (DG CLIMA) published the Reference Set of Technical Specifications for the non-CO₂ aviation effects MRV system. This document outlines the architecture of NEATS and its integration into the MRV process, detailing the key modules involved: the weather data integration module, fuel flow module, emissions calculation module, and climate effects module (weather-based approach). It also presents the path to addressing uncertainties in NEATS, which involves identifying key sources, integrating flight-specific and general uncertainty ranges, accounting for weather variability, and refining the system over time to ensure accurate CO₂e reporting.
The NEATS aims to simplify the MRV process for aircraft operators and verifiers; however, the tool is not yet publicly available. For this reason, the Commission has anticipated that until NEATS becomes available, the aircraft operator shall monitor at a minimum the flight information and aircraft type per flight, regardless of the method the operator has opted for (Method C or D); in other words, there is no difference in terms of data to be collected for small emitters and for other aircraft operators in the pre-NEATS environment. With this information from aircraft operators, the calculations will be performed at a later stage, once NEATS is made available.
