Global warming potential and abatement costs of different peatland management options: A case study for the Pre-alpine Hill and Moorland in Germany

Abstract

Natural peatlands are the world's most area-effective carbon sinks. However, over 90% of German, 40% of European and 10–20% of global peatlands have been degraded and converted into carbon sources, primarily because of agricultural drainage. Against this background, rewetting and more sensible uses of peat soils for agriculture are internationally recognized as effective potential options to mitigate greenhouse gas (GHG) emissions. This paper presents estimates of the GHG mitigation potential and abatement costs of different peatland management options by using the example of farm models that represent typical farm types in an intensive grassland-use peatland region in southern Germany. Therefore, an optimization model at the farm level that includes the emissions from all relevant sources in the production process is used.The current net GHG emissions of the farm models range from 10 to 12.9tCO2eha−1a−1, of which the peat soil-borne emissions make up a noticeable share. The rewetting and conversion of medium-drained grassland into wet grassland lead to considerable reductions of GHG emissions. However, in intensively managed dairy farms, the full emission mitigation potential of these peatland management options is not realized, because necessary adaptations increase emissions from other sources. Because of its low GHG mitigation potential, the conversion of arable land into medium drained intensive grassland leads to high abatement costs of up to 92 €/tCO2e, while the abatement costs of the rewetting and conversion into wet grassland range from 5 to 57 €/tCO2e. The results vary by farm type, intensity of agricultural peatland use to date and the share of peatland area on a farm. This stresses the need for individual farm approaches and impact analyses for planned peatland renaturations. The findings also show that the overall costs to compensate farmer income loss from planned peatland renaturations will be as high as they are for more intensively managed dairy farms, which will be located in and affected in the respective area. The modelling approach presented has the potential to be adapted to the needs of peatland farm systems in other countries of the temperate zone.