Effects of planned relocation on communities’ future coastal inundation risk

Abstract

The planned, permanent relocation of entire communities away from areas facing sea level rise (SLR) and coastal floods is an increasingly recognized strategy for climate change adaptation. Yet, planned relocations may or may not reduce risk. We assess projections of future coastal flooding in all the completed or underway relocations that met our criteria for inclusion from a global dataset. Most of the 17 cases achieved exposure reduction with less future inundation in destinations than origin sites, but the extent varies across time and emissions scenario. In all cases, origin sites are projected to be exposed to SLR combined with a once-per-year flooding event. In nine cases, even destination sites are projected to be exposed to SLR plus a once-a-year flooding event under some scenarios. Small island-to-small island relocations had more projected inundation in destinations than moves from a small island-to-mainland, or from mainland-to-mainland.