Efficiency in the design of coastal erosion adaptation strategies: An environmental-economic modelling approach

Coastal zones host between 15% and 40% of the world population, important residential, tourism and port infrastructures, and a wide variety of terrestrial, aquatic and coastal ecosystems. These built and natural capitals, corresponding services and associated values may be lost due to coastal erosion. Coastal erosion adaptation strategies are frequently based on the adoption of adaptation measures at the local scale (i.e. 'best practices') - we argue that the factual costs, impacts and benefits of coastal erosion adaptation strategies are determined by the suit of adaptation measures at the landscape scale. Sustainable economic development of coastal regions requires balancing of the marginal costs and associated marginal benefits from coastal erosion adaptation strategies. In this paper, we develop and apply the Coastal Erosion Adaptation Strategies (CEAS) approach, a spatially explicit environmental-economic modelling approach that allows for the identification of efficient (welfare maximizing) coastal erosion adaptation strategies in coastal socio-ecological systems. Results for the case of groin systems along the Central Portuguese coast show that while the protection of urban as well as natural areas may be optimal from an environmental-economic perspective, budget constraints provoke the loss of natural areas in favour of the protection of urban areas.