Klimaschutz durch Wiedervernässung von Niedermoorböden: Wohlfahrtseffekte am Beispiel der Eider-Treene-Region in Schleswig-Holstein

Abstract

Greenhouse gas emissions could be mitigated to a large extend and at low costs by high groundwater tables in fen areas. Pars pro toto this is demonstrated via simulation analyses using the Eider-Treene-Niederung as an empirical example located in the state of Schleswig-Holstein in North Germany. In particular, two scenarios of an extensified land management of fen areas, i.e. raising groundwater by 10 cm and 20 cm, respectively, are simulated implying average adaption costs ranging from 12 €/t CO₂-eq/year for the 10 cm scenario to 17 €/t CO₂-eq/year for the 20 cm scenario. Mitigation costs, however, vary significantly across farm types, ranging from 112 to 359 €/ha/year, where especially for dairy farms high costs are found. Since mitigation costs mainly result from changed land use these are significantly determined by assumed milk prices, where capitalization of annual costs imply land value losses ranging from 2240 € to 7018 € per ha. Assuming induced mitigation costs would be fully compensated via global per hectare payments based on average farm losses induces a redistribution of farm profits across individual farms. In particular, our simulation analyses result that especially large dairy farms as well as farms fattening cattle would benefit with farm profits increased by 300€/ha/year corresponding to a land value gain of 6000€/ha. In contrast, small farms would realize a profit loss of up to 220€/ha corresponding to a decrease in land value of 4440 €. As a result, the structural change of farm sizes in this area would ceteris paribus be accelerated by groundwater rise measures. However, in the long-term perspective, public expenses could be further reduced due to the less intensive water pumping in this area. Hence, overall, we conclude, that in comparison to other greenhouse gas mitigation measures, high soil water levels in fen areas can be considered as a low cost option to reduce greenhouse gas emissions. Moreover, the establishment of a seasonal groundwater management providing high groundwater tables during winter and lower soil water tables during summer (average of 30 cm below soil surface) would allow an extensive dairy production while simultaneously reducing greenhouse gas emissions significantly.