Coastal adaptation dynamics under future shoreline changes

Coastal adaptation dynamics under future shoreline changes

Currently 24% of the worlds sandy beaches are eroding with rates exceeding 0.5m/ year, and future climate conditions of increased storm wave action and sea level rise (SLR) are likely to increase the rate of shoreline recession in a large part of the world. The loss of sandy beaches affects coastal communities by degrading natural flood protection and coastal amenities. People experiencing these changes may choose to adapt by implementing flood protection measures, or by migrating towards safer areas. To maintain beach width, a growing number of coastal managers is investing in beach renourishment projects. Beach renourishment restores coastal amenity value and flood protection, allowing further coastal development. Current assessments of coastal adaptation in face of SLR often do not account for the interactions of household adaptation and coastal management decisions on coastal flood risk. In this study we aim provide a better representation of coastal adaptation dynamics by simulating the interactions between coastal management decisions and household adaptation behavior under sea level rise. Therefor we develop an agent-based model grounded in expected utility theory, that simulates household and government agents adapting to shoreline change and increasing coastal flood risk. The model is calibrated using empirical survey data on household adaptation and household characteristics are derived from local census data. We then apply the model in France to simulate coastal adaptation dynamics for 2020-2080 under different Shared Socioeconomic Pathways (SSP) and climate change scenarios. By explicitly simulating coastal adaptation decisions and we provide a more realistic model of coastal adaptation dynamics under future development.