ESTIMATING ADAPTATION COSTS TO SEA LEVEL RISE USING COASTAL STRUCTURES ON JAPANESE COASTS

Abstract

 Since preparing for anticipated sea-level rises resulting from climate change is a critical issue in coastal areas, this study investigates the costs of protective measures against increasing sea levels using coastal structures, which are assumed to be the construction costs of several coastal revetment types. Specifically, three coastal revetment types were investigated (sloped, upright, and composite), and their relative construction costs were calculated based on cross-sectional views provided in Shibata et al. We also estimated the cost of raising the crown height by replacing some parts. Herein, representative concentration pathway (RCP) 8.5 and RCP 2.6, as promulgated in the 2014 Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), were used as climate change and sea-level rise scenarios. Our investigation showed that the costs for adapting to anticipated sea level rises would be between 668 billion and 2.96 trillion yen (depending on the revetment type, without existing revetment). This result, which assumes that such revetments would be constructed and raised on all Japanese coasts, is expected to provide helpful information that will assist planners in formulating and implementing practical and effective adaptation measures.