Through state-of-the art ecosystem modelling supported by ecological experimental data, the COMTESS Project (funding: German Federal Ministry of Education and Research) investigates potential synergies and trade offs in ecosystem service provision under different land-use scenarios in two German coastal areas till 2100. Overall goal is to explore alternative sustainable land-use strategies to best adapt to climate change. Two science-based land- use scenarios were developed for two study regions on the Baltic and North Sea coasts to contrast a business-as-usual scenario. We focus here on the Baltic Se case region. The underlying premise of these alternatives is managed realignment of current dikes inland for: 1) climate mitigation through wetland re-naturation or 2) multiple land use, including biomass harvesting for energetic purposes (Baltic Sea). Managed realignment is increasingly considered as a valid coastal defence strategy to lower long-term costs of hard coastal defence and restore critical coastal and experiments have been initiated since the 1990s in a number of northwest European countries. Though politically highly controversial and facing much public antagonism, managed realignment is effectively embedded in the current coastal management policy of the state of Mecklenburg Vorpommern on the German Baltic coast. Implementation, nevertheless, faces many obstacles. Project-based scenarios for the Baltic Sea were first evaluated by key regional and local policy, management and land use practitioners, each expert in their field of activity. Their evaluation and recommendations were subsequently used to develop a fourth land-use scenario. Using qualitative empirical social research methods we analyse divergences and convergences between expert views on the projects scenarios. We argue that managed realignment is currently being mainstreamed in science, policy and resource management arenas although representatives of local land users and inhabitants do not endorse this strategy and still foster a hard defence approach to coastal zone management. This is best illustrated in recurrent social mobilisation and resistance to managed realignment proposals. This points at important perception and preference gaps between science, policy and land users / inhabitants, which need to be resolved to formulate and implement sustainable and socially acceptable land use strategies.