Coastal settlement patterns and exposure to sea-level rise in the Jaffna Peninsula, Sri Lanka

The Jaffna Peninsula in Sri Lanka has a generally flat topography with a median elevation of 2.72 m, and thus faces a high risk from sea-level rise that has the potential to have adverse impacts on the livelihoods of coastal communities. Understanding these risks and identifying the regions that could be adversely impacted is critical for planning future settlements and developing preventative protocols where possible. The aim of this study was to analyze the exposure of coastal settlements of the Jaffna Peninsula to climate risks, particularly to sea-level rise, and to identify the areas that are likely to be impacted under different sea-level rise scenarios. Raster-based sea-level rise modeling was performed with a digital elevation model produced with topographic contours and spot heights. The spatial distribution of individual residential houses for the entire Jaffna Peninsula was obtained through manual digitization using virtual globe platforms and high-resolution satellite images, and the houses exposed to inundation under various Representative Concentration Pathways from 2025 to 2100 were identified. The results showed that a majority (55.5%) of the residential buildings in the Jaffna Peninsula are located within 3 m above sea level. Approximately 5554 (5.6%) of the houses were projected to be inundated by 2100, and this projection increased to approximately 25,074 (25.4%) under high tide scenarios. This study highlights the coastal communities with a high level of exposure to coastal inundation where adaptation planning is essential. These results provide insights for coastal managers and policy makers for future planning of new settlements and urban expansion.