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

Abstract

We present the first high-resolution (500 m × 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 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 to 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 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

How does grassland management affect physical and biochemical properties of temperate grassland soils? A review study

“…CH 4 is mainly produced by methanogens-the end point of the anaerobic breakdown of organic matter (Whalen, 2005) -that are found in anaerobic microsites in the soil, water-saturated zones with high C content and the rumen of ruminants (Baldocchi et al, 2012;Hiller et al, 2014 that forages with high digestibility due to increased intake may decrease the amount of produced CH 4 per unit of feed consumed and per unit of animal product (Sollenberger et al, 2019).…”

“…Small part of the digested C is emitted by ruminant enteric fermentation in the form of CH 4 . CH 4 is mainly produced by methanogens—the end point of the anaerobic breakdown of organic matter (Whalen, 2005) – that are found in anaerobic microsites in the soil, water‐saturated zones with high C content and the rumen of ruminants (Baldocchi et al., 2012; Hiller et al., 2014). The high proportion (77%) of CH 4 emissions originates from enteric fermentation and are primarily varied with the stocking rate, although a considerable amount (9%) of CH 4 is released as a result of manure decomposition processes (FAOSTAT, 2017).…”

Source partitioning of atmospheric methane using stable carbon isotope measurements in the Reuss Valley, Switzerland

“…The main CH 4 sink, i.e., atmospheric OH, reacts on a longer timescale and on larger spatial scales [2,13,20,25], and the sink strengths of different soils, which largely depend on the land-use type, are yet to be resolved on shorter timescales [18]. While CH 4 uptake of the nearby grasslands with -0.21 mg CH 4 m −2 d −1 do not contribute significantly to the CH 4 budget [56], forest soil uptake rates were estimated at up to -1.5 mg CH 4 m −2 d −1 [10,11]. This is only 1% of the nocturnal boundary-layer budget flux of 138 ± 27 mg CH 4 m −2 d −1 computed by Stieger et al [57].…”

“…Particularly top-down approaches [e.g., 9] are generally underconstrained, thus CH 4 budgets remain substantially uncertain, since the small-scale variability is often smoothed out [6]. But also for bottom-up approaches [e.g., 10,11], measurements covering the spatio-temporal variability of CH 4 emissions are scarce. In addition, measurements of atmospheric CH 4 over heterogeneous areas always represent a mixture of different sources, which is rarely partitioned into the individual contributions resulting in uncertain emission estimates by source sector [4].…”

A dual tracer ratio method for comparative emission measurements in an experimental dairy housing

“…According to model calculations, 94% of total NH 3 emissions in Switzerland were attributed to farming in 2007, a third of which can be traced to livestock housing (Achermann et al, 2009;Kupper et al, 2013). Similarly, 81% of methane (CH 4 ) and 79% of nitrous oxide (N 2 O) emissions in Switzerland originated from agriculture in 2014 (FOEN, 2016), with CH 4 being primarily produced by enteric fermentation of ruminants (Hiller et al, 2014;Eyer et al, 2016;Röckmann et al, 2016) and N 2 O mainly emitted by microbial activities in natural and fertilized soils (Mohn et al, 2012;Fowler et al, 2013;Mohn et al, 2013;Wolf et al, 2015).…”