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

• Main Authors: R. V. Hiller, D. Bretscher, T. DelSontro, T. Diem, W. Eugster, R. Henneberger, S. Hobi, E. Hodson, D. Imer, M. Kreuzer, T. Künzle, L. Merbold, P. A. Niklaus, B. Rihm, A. Schellenberger, M. H. Schroth, C. J. Schubert, H. Siegrist, J. Stieger, N. Buchmann, D. Brunner
• Format: Article
• Language: English
• Published: Copernicus Publications 2014-04-01
• Series: Biogeosciences
• Online Access: http://www.biogeosciences.net/11/1941/2014/bg-11-1941-2014.pdf
• ISSN: 1726-4170; 1726-4189

We present the first high-resolution (500 m × 500 m) gridded methane (CH₄) emission inventory for Switzerland, which integrates 90 % of 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 Gg CH₄ yr^−1), mainly produced by ruminants and manure management, followed by emissions from waste management (15 Gg CH₄ yr^−1) mainly from landfills and the energy sector (12 Gg CH₄ yr^−1), which was dominated by emissions from natural gas distribution. Compared with the anthropogenic sources, emissions from natural and semi-natural sources were relatively small (6 Gg CH₄ yr^−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 Gg CH₄ yr^−1), while forest soils are a CH₄ sink (approx. −2.8 Gg CH₄ yr^−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 an European (TNO/MACC) CH₄ inventory. This new spatially explicit emission inventory for Switzerland will provide valuable input for regional-scale atmospheric modeling and inverse source estimation.