Assessment of methane emissions from European countries using satellite and surface observations

Abstract. Europe is a global leader in mitigating methane emissions through comprehensive policies, including the EU Methane Strategy and commitments under the Global Methane Pledge. National bottom-up inventories are widely regarded as high quality; however, atmospheric observations remain essential for independent verification and tracking emission reductions. Here, we present a multi-year (2019–2023) top-down assessment of European methane emissions using a Bayesian inversion of satellite observations from TROPOMI and surface measurements from ICOS. Analysis of observational constraints shows that surface measurements provide the dominant information, while satellite observations offer complementary coverage in regions not covered by the surface network. The inversion estimates total European methane emissions at 24.7 Tg yr⁻¹, including 22.1 Tg yr⁻¹ from anthropogenic sources, which is 1.0 Tg yr⁻¹ higher than the prior inventory. The upward revision is mainly attributed to livestock and waste emissions in central and western Europe, partly offset by lower fossil fuel emissions in the North Sea. National emissions for the Netherlands, Germany, and Italy are 27–62 % higher than reported to the UNFCCC. The inversion also reveals an overall decline in anthropogenic emissions (–0.27 Tg yr⁻²). While consistent in magnitude with the prior estimate, the inversion shows a distinct spatial pattern: increases in livestock and waste emissions in western Europe contrast with decreases in fossil fuel production regions such as the North Sea and Poland. These findings highlight the value of atmospheric observations for evaluating methane inventories and informing climate policy.