Bridging Science and National GHG Inventories: Insights from the PARIS Project – Process Attribution of Regional Emissions

Strengthening the link between scientific research and official greenhouse gas (GHG) reporting is an important step under the Paris Agreement’s Enhanced Transparency Framework. The PARIS Project, funded by Horizon Europe, is working with eight European countries to develop practical tools for this purpose.

A central innovation of PARIS is the development of draft annexes to National Inventory Documents (NIDs). These annexes provide a structured and transparent interface between official bottom-up inventories and top-down atmospheric estimates. They do not alter formal reporting rules; instead, they document how independent scientific assessments compare with inventory estimates, identify consistencies and discrepancies, and highlight where further investigation or methodological development is warranted. In this way, the annexes enable inventory compilers, policymakers, and scientists to interpret atmospheric results within the legal and institutional framework of national reporting.

The annexes are underpinned by major advances in PARIS observation and modelling capacity. Expanded and harmonised networks for CH₄, N₂O, F-gases, and aerosols, together with multi-model inverse systems and common data standards publicly available on the ICOS Carbon Portal, provide robust, traceable estimates of regional emissions and their sectoral drivers. These scientific outputs are synthesised in the annexes in a form that is directly usable by inventory agencies.

Through close engagement with national inventory teams in the UK, Switzerland, Germany, Ireland and other focus countries, PARIS has co-developed annex templates and begun populating them with results from multiple inversion systems. This process reduces barriers between the research and inventory communities and supports routine, transparent comparison of bottom-up and top-down estimates.

The poster will present the main outcomes of the PARIS project, demonstrating how the outcomes advance and embed atmospheric science in national GHG reporting to strengthen confidence in emission estimates, improve process attribution of regional emissions, and ultimately support more effective climate policy under the Paris Agreement.