Driving Precision in Climate Impact Assessment
In May 2025, the European Commission published a critical document aimed at enhancing the monitoring, reporting, and verification (MRV) of aviation’s non-CO₂ effects. As climate science advances, the aviation sector is under growing pressure to measure its full environmental footprint—not just carbon dioxide. These new high-level guidelines support the integration of new modules and models into the EU’s MRV system, reflecting this ambition to keep pace with evolving knowledge.
NEATS: The Core Framework
At the heart of the updated system is the Non-CO₂ Aviation Effects Tracking System (NEATS), an information technology tool developed to quantify the climate impact of non-CO₂ emissions. The architecture of NEATS is deliberately open and modular, designed to integrate improvements over time as new scientific insights emerge.
The EU now officially supports the use of third-party or custom-built IT tools—referred to as “new IT tools”—by aircraft operators. However, to ensure consistency and reliability, such tools must be formally assessed and approved by the European Commission in accordance with Article 56a of the Monitoring and Reporting Regulation (MRR).
Tool Categories and Assessment Pathways
The guidance outlines four categories of tools based on their similarity to NEATS:
- Tools based on NEATS with minor modifications
- Tools using NEATS with some modules replaced
- Tools incorporating some NEATS elements
- Entirely different tools developed independently
Each category has different evaluation requirements, but all must ultimately meet rigorous scientific and technical standards. Evaluation focuses not just on individual components, but on system-wide integrity, including data format compatibility and consistent climate impact calculations.
Scientific Rigor and Regulatory Compliance
Any new IT tool must model climate-relevant processes—such as contrail-induced cirrus clouds or NOₓ effects on ozone and methane—based on robust scientific evidence. Tools must also handle complex meteorological and fuel-specific data inputs and outputs in alignment with existing NEATS specifications.
If a tool introduces novel processes (like aerosol radiative forcing), developers must submit peer-reviewed publications, demonstrate scientific necessity, and provide detailed model documentation.
Evaluation Process: A Two-Step Approach
Approval of a new tool follows a structured two-phase process:
- Step 1: The applicant tests the tool against a “golden standard” set of flight scenarios covering diverse weather, fuel, and trajectory variables.
- Step 2: The European Commission independently verifies performance using broader datasets to ensure general applicability and avoid bias.
Comparisons with NEATS are essential to determine if the new tool offers equal or improved accuracy in calculating CO₂ equivalents (CO₂e) across different flight types and atmospheric conditions.
Continuous Updating and Open-Source Licensing
The NEATS system and any approved new tools will undergo regular updates. These include bug fixes, module upgrades, new data integrations, and adaptation to future aircraft and engine technologies. To maintain trust and transparency, the Commission strongly advocates for these tools to be open source, ensuring wider access and peer validation.
Conclusion
These guidelines mark a significant step in aligning the aviation industry with Europe’s climate targets. By enabling scientific innovation while maintaining regulatory discipline, the EU ensures that climate accountability in aviation moves forward, driven by data, transparency, and continuous improvement.
Download Document File Here: High-level guidelines for integrating new modules and models to the EU monitoring, reporting and verification (MRV) system