The PARIS project, funded by Horizon Europe, is supporting national efforts of eight European countries to improve greenhouse gas (GHG) reporting by strengthening the link between scientific research and official inventory systems, particularly by developing tools and methodologies for the systematic comparison and reconciliation of combined bottom-up and top-down estimates in a policy-relevant context. A key instrument in this effort is the development of draft annexes designed to complement National Inventory Reports (NIRs). A first set of draft Annexes to National Inventory Reports provides an overview of how this approach is being implemented across participating countries.
Purpose of the Annexes
The annexes are intended to serve as structured, optional supplements to existing NIRs. Their main function is to provide space for incorporating emerging scientific information—particularly from atmospheric observations and inverse modelling studies—into the broader inventory framework. These annexes are not a replacement for nationally determined methodologies; instead, they offer an opportunity to introduce additional context, comparisons, and uncertainty analysis in a format that is aligned with UNFCCC expectations.
By enabling this exchange, the annexes aim to improve transparency, support methodological consistency, and highlight areas where scientific and inventory-based approaches may converge—or diverge—in their estimates of national emissions and removals.
Structure and Content
The draft annexes follow a consistent format across countries and include several core sections. These typically cover:
- Key category analysis, identifying sectors or gases with significant influence on total emissions;
- Uncertainty assessments, using both national and research-derived data sources;
- Comparisons between inventory and reference estimates, including initial insights from top-down (atmospheric) methods;
- Methodological explanations, including recalculations and improvements;
- Quality assurance and control (QA/QC) procedures, and;
- Standardized reporting tables, designed to align with UNFCCC Common Reporting Tables (CRTs).
This structure allows for both comparability across countries and flexibility in addressing country-specific data availability and research collaborations.
Relevance for Researchers and Policymakers
For policymakers, the annexes provide a transparent and organized view of how independent scientific assessments relate to the official inventory. They can help identify areas where improvements or additional research may be warranted, without requiring immediate changes to formal reporting practices.
For researchers, the annexes offer a practical channel for contributing to national reporting in a way that respects institutional roles and legal frameworks. They also promote collaboration between inventory agencies and the scientific community, especially in interpreting results from inverse modelling, atmospheric observations, and other top-down approaches.
Looking Forward
The annexes presented by PARIS are considered drafts and will be refined over time, based on further collaboration with inventory teams and updated scientific data. They are intended to evolve alongside the PARIS project’s measurement and modelling activities, and to be updated annually where possible.
Ultimately, these annexes serve as a testbed for integrating scientific innovation into official climate reporting. By providing a structured and transparent format for this exchange, the PARIS project supports the goals of the Paris Agreement’s Enhanced Transparency Framework and strengthens the overall robustness of GHG reporting systems.
