EYE-CLIMA: A Horizon Europe project to support national inventories for emissions of climate forcers

National greenhouse gas inventories (NGHGIs) and Biennial Transparency Reports (BTRs) on emissions and removals are crucial elements of the Paris Agreement and its Global Stocktake. However, NGHGIs are subject to significant uncertainties, owing to uncertain emission factors and/or insufficient activity data, thus there is a need for their independent verification. One method to do this is through atmospheric inversions, which use atmospheric observations in a statistical optimization framework to estimate surface-to-atmosphere fluxes. This method of verification is referred to in the 2006 IPCC Guidelines on national reporting and in their 2019 refinement. However, atmospheric inversions have been hitherto considered too complex and inaccurate at national scales to be widely used for this purpose.

EYE-CLIMA is a Horizon Europe project that aims to develop the atmospheric inversion methodology to a level of readiness where it can be used to support the verification of NGHGIs. The overarching goals are to: i) develop a best practice in atmospheric inverse modelling for estimating emissions at national scale, including a full assessment of the uncertainties, ii) develop the methodology on how to prepare sectorial emission estimates from atmospheric inversions and make these comparable to what is reported in NGHGIs, iii) work together with NGHGI agencies on projects piloting the EYE-CLIMA methodology of emissions verification and iv) develop international best practices for the quality control of NGHGIs. EYE-CLIMA covers CH₄, N₂O, 5 HFC species, SF₆, and the black carbon (BC) aerosol. This presentation will focus on the set-up of the EYE-CLIMA project and provide an overview of the first results in support of NGHGI verification.