Modelling soil erosion by water under future climate change: Addressing methodological gaps

Soil erosion by water from arable land poses a serious threat to on-field agricultural productivity and the wider environment through off-site damage. Multiple studies show that climate change will worsen the impacts of soil erosion in various regions. However, these studies are limited by (1) the lack of any thorough evaluation process in applying climate scenarios to drive soil erosion models, and (2) the failure to consider the role of changing land use under future climate change, despite the evidence that it is more important than rainfall changes in driving increased erosion. Using the WEPP soil erosion model, these methodological gaps are addressed in this study for a small catchment in Belgium that is both heavily impacted by soil erosion and boasting an extensive array of mitigation measures. We develop a novel and comprehensive methodology to rigorously and efficiently select suitable climate models specifically for simulating soil erosion by water, and examine the impact of a range of environmentally and economically viable land use choices on soil erosion. The main findings reveal that our climate model selection methodology is successful in generating the widest range of likely future scenarios from a small number of models, compared with other selection methods. Our novel methodology reveals that the magnitude and frequency of soil erosion events will increase considerably under the mean of all scenarios between 2041 and 2100 with existing land management. Winter wheat represents the most economically and environmentally viable land use choice to effectively mitigate future soil erosion when compared to other land use alternatives under the full range of likely future climate scenarios. This research illuminates the importance of carefully tuned climate model selection and land use changes for modelling future soil erosion by water so the best- and worst-case scenarios can be adequately prepared for under a changing climate.