Preparing for Non-CO₂ EU ETS MRV Compliance Strategies for Airlines

The aviation industry is navigating a major shift in sustainability regulations. A new mandate from the European Union is expanding the scope of its Emissions Trading System (EU ETS) beyond carbon dioxide to include the significant climate impact of non-CO2​ effects. For airlines, this introduces a new layer of complexity and a critical need for a robust compliance strategy.

In a recent webinar, Nexus Lab co-founders Omar Nuruzade and Gular Ismayilova broke down these evolving regulations to help airlines cut through the noise and prepare for what lies ahead. Here’s a summary of the key insights and actionable strategies discussed.

More Than Just CO2: Why Contrails are Now in Focus

For years, the white trails left by aircraft, known as contrails, were seen as little more than temporary clouds. However, scientific understanding has evolved dramatically. The Intergovernmental Panel on Climate Change (IPCC) now estimates that the total climate impact from aviation could be 35% more than the impact of its CO2​ emissions alone.

The main issue is that under certain atmospheric conditions, contrails can spread into contrail-cirrus clouds that act like a blanket, trapping heat in the atmosphere. With the science becoming undeniable, the 2023 revision of the EU ETS formally recognized that non-CO2​ effects could no longer be ignored, setting the stage for the new regulations.

The MRV System: A New Framework for Accountability

To manage this, the EU is implementing a Monitoring, Reporting, and Verification (MRV) system. The core purpose of the MRV is to create a standardized method for airlines to track, report, and validate their non-CO2​ emissions data.

Starting from January 1, 2025, monitoring and reporting are required. The data collected during this initial phase will be the foundation for future policy decisions, making the accuracy and quality of this early data critically important.

The Roadmap: Scope and Key Deadlines

The EU is taking a phased approach to implementation:

Phase 1 (January 2025 – December 2026): Mandatory reporting begins for the “reduced scope”. This includes:

• All flights between airports within the European Economic Area (EEA).
• All flights departing from an EEA airport to the United Kingdom or Switzerland.
• Flights to and from the EU’s “outermost regions” (OMRs) like the Canary Islands and the Azores are also covered under this mandatory scope from the start.

Phase 2 (Starting in 2027): Mandatory reporting will expand to cover all flights, including inbound and outbound international routes from the EEA.

While reporting on non-EEA flights is deferred until 2027, airlines have the option to report this data voluntarily from the beginning.

The Heart of Compliance: Your Data Strategy

At the center of this new requirement is the airline’s Monitoring Plan, a document that now covers both CO2​ and non-CO2​ effects. Within this plan, airlines face a crucial choice that will define their reporting accuracy: using

Primary Data versus Secondary Data.

• Secondary Data: This is the default option provided by the EU’s new IT tool. While it is designed to be easy and reduce administrative burden, it relies on conservative default values for everything from flight paths to fuel burn. This will almost certainly lead to an overestimation of your airline’s actual climate impact.
• Primary Data: This is your airline’s own measured, operational data. While it requires more effort to collect and manage, it provides a far more precise and accurate reflection of your actual impact. Using primary data gives you control and helps avoid the penalties associated with overestimation.

To achieve the highest accuracy, airlines should focus on providing primary data for key parameters such as:

• Flight Trajectory: Your actual 4-dimensional flight path, not a default route.
• Aircraft Properties: Specifics like the unique engine UID, which can dramatically impact results compared to default values for an aircraft type.
• Aircraft Performance: Actual take-off weight and verified fuel flow data instead of relying on generic models.

The EU guidance encourages submitting your own verified fuel flow data if you notice the system is estimating higher fuel usage than what was actually burned.

Beyond Compliance: The Strategic Advantage

Managing the complexities of primary data—from flight trajectories to fuel properties and aircraft mass—can be an overwhelming operational challenge. This is where a centralized data platform becomes essential. By automating data consolidation and reporting, airlines can save significant time—equivalent to about half of a full-time employee’s workload—and redirect that focus toward more strategic initiatives.

More importantly, a smart data strategy leads to vastly improved accuracy. Case studies show that using high-quality primary data can result in reporting that is two to three times more accurate. Furthermore, by using sensitivity analysis, airlines can identify which data points have the biggest influence on their final emissions score, allowing for a more targeted and effective data collection strategy.

Key Takeaways for the Path Forward

As you prepare for these new regulations, keep three core principles in mind:

• This is a Fundamental Shift: These rules are real and here to stay. They form the foundation for future climate policy in aviation.
• Your Data Strategy is Crucial: Opting for high-quality primary data is the most effective way to ensure your reporting is accurate, fair, and avoids the pitfalls of overestimation.
• The Time to Prepare is Now: The airlines that build a smart data strategy today will be in a much stronger and more competitive position as these regulations expand.