Wind waves in the Adriatic Sea under a severe climate change scenario and implications for the coasts

Wave climate projections at global scales are often of little direct use for local or regional coastal applications, where bathymetric gradients and coastal geometry dominate onshore wave propagation and transformation. In such systems, and even more in the case of semi-enclosed basins where coastal orography can play a major role in wind modulation, wave climate assessments require a specific effort, with particularly strict prescriptions in terms of model resolution and quality of the wind forcing. In this work, we provide a numerical modelling estimate of the expected variations of wave regime in the Adriatic Sea (a semi-enclosed basin of the Mediterranean Sea) under an IPCC RCP 8.5 climate change scenario at the end of the current century, focusing on the implications for energy modulation in the coastal regions. Results tend to confirm the evolution towards an overall decrease of wave storminess in the basin, as suggested by previous studies, but show that some regions might experience a local increase in the severity of the sea states impacting the coast. The model resolution and the unprecedented directional skills of the climatological wind forcings allow to ascribe this behaviour to a shift in the directional wind regime that can be related to a northward translation of the Mediterranean cyclones trajectory. Although in the absence of a quantitative assessment of the uncertainty associated with the choice of the climate model, our results give an account of the possible extent of the spatial variability of the response of coastal dynamics to mid-latitude storm tracks modification induced by climate change.