Projected Climate Change Impact on Soil Erosion and Sediment Yield in the River Elbe Catchment

The scope of this paper is to analyse the impact and the uncertainty of climate change on soil erosion and consequent sediment yield in the River Elbe catchment by ensemble modelling techniques. The model ensemble comprises five bias-corrected and gridded climate data-sets that origin from coupled runs of global circulation models (GCM) and regional circulation models (RCM) that were driven by both the C20 and the A1B emission scenarios. The data-sets were aggregated for climate normals that are referred to as C20 (1961–1990), ‘near future’ (2021–2050) and ‘far future’ (2071–2100). Furthermore, the HYRAS data-set that covers the period 1961–1990 of gridded station data was used as the actual climate data. First, the PESERA-model was chosen as a climate impact model to simulate soil erosion on a 500 × 500 m grid within the entire River Elbe catchment based on relief-data, land cover, soil, crop and the aforementioned climate data. Second, the simulated annual average soil erosion for the actual climate and each projected climate was used to calculate sediment delivery with the approach of spatially distributed sediment delivery ratios (SDR-approach). The actual simulated soil erosion using the actual climate data is in good agreement with other published soil erosion maps for this scale. Furthermore, averaged soil erosion per land use class meets reported data in literature well. Highest soil erosion rates are simulated in the South-East of the catchment and in the range of hills in the central part of the River Elbe catchment. Simulated sediment yield was over predict by a factor of two, that can be attributed because of the methods sensitivity of the underlying river network map and the temporal shift between both periods of actual climate data and reference data on suspended solids load. Sediment delivery slightly drops in the ‘near future’ and ‘far future’, which coincidences with decreasing summer rainfalls. However, results of sediment delivery are largely dominated by the chosen GCM-RCM models. It is concluded that the impact of climate change on soil erosion is lower than the impact of potential land cover change.