Coastal dynamics in a climate change context: Evidence from Demak regency, Indonesia

Climate change contributes to sea-level rise, tidal flooding, and shoreline erosion in many coastal regions worldwide. Demak Regency, located on the northern coast of Central Java, Indonesia, has experienced significant coastal environmental change over the past three decades. This study examines the spatio-temporal dynamics of the Demak coastline over a 30-year period through analyses of shoreline change, coastal vulnerability levels, and tidal inundation. Four multi-temporal Landsat images acquired in 1993, 2003, 2013, and 2023 were analyzed using the Digital Shoreline Analysis System (DSAS) to quantify shoreline change, the Modified Normalized Difference Water Index (MNDWI) to map inundation extent, and a Coastal Vulnerability Index (CVI) based on three physical parameters. The results indicate severe shoreline erosion, particularly in Sayung Subdistrict, where the mean End Point Rate (EPR) reached −32.92 m/year. Approximately 56% of the Demak coastline falls within the very high vulnerability category, particularly in areas experiencing severe shoreline retreat and extensive inundation. Tidal inundation expanded substantially across the coastline, with Sayung recording the largest cumulative increase in inundated area, reaching approximately 3946 ha. These findings demonstrate extensive coastal degradation and ongoing loss of productive coastal land, with important implications for the economic, social, and ecological resilience of coastal communities.