Roadmap for the rewetting of organic soils in Germany

Background and Objective

The majority of peatlands in Germany have been drained for agriculture, among other land uses, and thus contribute strongly to greenhouse gas (GHG) emissions from agricultural land. The GHG emissions correspond to about 7.5% of total German emissions and to 44% of emissions from agriculture and agricultural land (UBA 2022). According to the amendment of the Climate Change Act, the sector Land Use, Land Use Change and Forestry (LULUCF) is expected to provide a GHG sink of 40 million t CO₂-eq. a^-1 by 2045 (Bundesrat 2021). 

This cannot be achieved without considerable efforts in peatland rewetting. As the comprehensive drainage of peatlands was driven by governmental action, a transformation towards rewetting should also be seen as a societal task and not be assigned to individual land users.

Due to the importance of GHG emissions from drained organic soils used for agriculture, land use alternatives in combination with rewetting of organic soils are urgently needed. The GHG mitigation potential will be high if the water level is raised as close to the surface as possible, but conventional cultivation of the land is hardly possible thereafter. Here, wet land use options such as paludiculture (Projekt Niedermoorbiomasse) or "peatland PV" (EEG 2023) offer promising alternatives for farmers under appropriate conditions. Under other circumstances, full rewetting or ditch blocking combined with low-intensity land use or abandonment might be suitable options. However, economic scenarios for land use options such as raising water levels in combination with low-intensity use, full rewetting and abandonment (BEWAMO) :), paludiculture or photovoltaics are largely lacking. For an economic assessment, the costs arising from drainage induced damage to infrastructure need also be considered (see e.g. PBL Netherlands Environmental Assessment Agency 2016, Page et al. 2021). Further, the analyses of the institutional and legal framework conditions are required to formulate rewetting strategies.

The overarching aim of the project is to develop an implementation concept ("roadmap") for the rewetting of organic soils in Germany. For this purpose, site-specific land-use options will be developed and evaluated with regard to their mitigation potentials and economic efficiency. To foster implementation, the extent to which institutional and legal framework conditions need to be adapted and how the transformation could be supported through participation and coordination processes, efficient funding and further incentive mechanisms will be examined. In order to develop this roadmap, the following objectives will be pursued:

• estimation of the technical and economic potentials of rewetting and different land use options,
• improvement of the data basis on rewetting measures and development of methods for integrating the mitigation effects into the roadmap and the GHG inventory,
• economic analysis of new land use options including paludiculture and peatland PV,
• economic assessment of different options for rewetting considering different policy mix scenarios and institutional and legal frameworks,
• identification and improved understanding of success factors for rewetting projects,
• development of efficient policy instruments that ensure sufficient income alternatives for users of rewetted organic soils in the long term.

Approach

The project is organized into several work packages and combines natural science data and models with social science, economic and legal analyses to create an implementation concept for rewetting organic soils in Germany. The updated map of organic soils (Wittnebel et al. 2023), i.e. the entirety of peat and other organic soil, will serve as spatial basis for all analyses. The map has been developed as part of the project "Implementation of the German peatland monitoring programme for climate protection" (MoMoK). The work is being carried out in an interdisciplinary manner at four Thünen Institutes: Climate-Smart Agriculture, Farm Economics, Rural Studies and the Coordination Unit Climate and Soil. All partial results will be combined to form a roadmap for the implementation of rewetting. This roadmap will contain estimates of costs and remuneration options, the impact of different land-use options on GHG emissions and needs for adjustments to the institutional and legal framework as well funding.