Anthropogenic and natural methane fluxes in Switzerland synthesized within a spatially-explicit inventory.

We present the first high-resolution (500 m x 500 m) gridded methane (CH₄) emission inventory for Switzerland, which integrates the national emission totals reported to the United Nations Framework Convention on Climate Change (UNFCCC) and recent CH₄ flux studies conducted by research groups across Switzerland. In addition to anthropogenic emissions, we also include natural and semi-natural CH₄ fluxes, i. e., emissions from lakes and reservoirs, wetlands, wild animals as well as uptake by forest soils. National CH₄ emissions were disaggregated using detailed geostatistical information on source locations and their spatial extent and process- or area-specific emission factors. In Switzerland, the highest CH₄ emissions in 2011 originated from the agricultural sector (150 GgCH₄yr^-1), mainly produced by ruminants and manure management, followed by emissions from waste management (15 GgCH₄yr^-1) mainly from landfills and the energy sector (12 GgCH₄yr^-1), which was dominated by emissions from natural gas distribution. Compared to the anthropogenic sources, emissions from natural and semi-natural sources were relatively small (6 GgCH₄yr^-1), making up only 3% of the total emissions in Switzerland. CH₄ fluxes from agricultural soils were estimated to be not significantly different from zero (between -1. 5 and 0 GgCH₄yr^-1), while forest soils are a CH₄ sink (approx. -2. 8 GgCH₄yr^-1), partially offsetting other natural emissions. Estimates of uncertainties are provided for the different sources, including an estimate of spatial disaggregation errors deduced from a comparison with a global (EDGAR v4. 2) and a European CH₄ inventory (TNO/MACC). This new spatially-explicit emission inventory for Switzerland will provide valuable input for regional scale atmospheric modeling and inverse source estimation. [ABSTRACT FROM AUTHOR]