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

Rebecca Hiller ,D Imer,J Stieger,H Siegrist,Nina Buchmann ,Thomas Künzle ,Silas Hobi ,Ruth Henneberger ,Beat Rihm ,Carsten J Schubert ,Tonya Delsontro ,Lutz Merbold ,Michael Kreuzer ,Martin H Schroth ,Werner Eugster ,E L Hodson ,Pascal A Niklaus ,Andreas Schellenberger ,Torsten Diem ,Daniel Bretscher ,Dominik Brunner

doi:10.5194/bg-11-1941-2014

Abstract

Abstract. 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.

Highlights

Most of the atmospheric methane (CH4) produced in Switzerland results from anthropogenic activities
Part of the livestock is moved to Alpine pastures for grazing to save the resources in the valley for the winter. This practice is part of the traditional Swiss three-stage farming system (Bätzing, 2003) and CH4 emissions can be found in relatively remote areas of the Alps
A spatially explicit high-resolution CH4 inventory was developed for Switzerland for the year 2011. This is the first comprehensive inventory at national level synthesizing most of the available Swiss data sets on anthropogenic as well as on natural and semi-natural fluxes

Summary

Introduction

Most of the atmospheric methane (CH4) produced in Switzerland results from anthropogenic activities. These emissions are well documented in the Swiss Greenhouse Gas Inventory (SGHGI, FOEN, 2013) that is updated and communicated to the UNFCCC on an annual basis. Disposal of combustible waste in landfills has been prohibited since 2000 in Switzerland and emissions from this source are decreasing (FOEN, 2013). Counteracting this trend, emissions from biogas production have more than doubled since 1990 and are projected to rise even further (FOEN, 2013). A reliable baseline inventory for CH4 emissions from anthropogenic activities and natural processes is urgently needed

Objectives

Methods

Results

Conclusion