Climate change affects future sea-bed mobility via storms and sea level rise

Abstract How will climate change affect the composition of the seabed? Using three-dimensional hydrodynamic and wave models combined with climate projections from the Coupled Model Intercomparison Project phase 5, we investigate and quantify the drivers of seafloor stresses, using a North Western European Shelf case study. This study maps the potential for grain size mobilisation in present-day and future conditions, highlighting areas where transport capacity is likely to change. Sea level rise alters both absolute water depth and tidal dynamics, changing the magnitude and timing of seabed stresses while simultaneously reducing exposure to waves and currents. In contrast, increasing storm intensity in a warming climate is expected to cause more frequent episodic disturbance of an otherwise increasingly stable seabed. These predicted changes and their potential impacts on the benthic environment are discussed in the context of growing anthropogenic pressures and the associated challenges for marine spatial management.