Climate projections of sea level rise and associated coastal inundation in atoll islands: Case of Lakshadweep Islands in the Arabian Sea

Abstract

Rising global sea levels have been touted as the major threat that is going to affect small islands in the coming years. In this study, potential inundation that can occur in the small archipelago of Lakshadweep in the Arabian Sea was modelled using the climate model projections. The methodology involved evaluating the performance of CMIP5 Global Climate Models (GCMs) in simulating the sea level rise in the Arabian Sea using various statistical methods. GFDL-ESM2G and MIROC5 were found to be the best performing models in predicting the sea level rise ranging from 0.4 mm year−1 to 0.9 mm year−1 under various RCP scenarios. Although the maximum sea surface height values for the period of 2080–2100 predicted by the models i.e., 0.78 m is less than the global sea level rise projected by the IPCC (0.8–2.0 m), it does not imply that the islands are safe from rising sea levels. The projections obtained from the best performing models were then used to map the potential inundation that may occur under RCP 2.6, 4.5, and 8.5 scenarios. The study signifies that all the islands within the archipelago may be vulnerable to the effects of sea level rise, with the capital Kavaratti projected to experience inundation along much of its coastline under all forcing scenarios.