Keywords
Abstract
The Indian Sundarbans, where the Ganges–Brahmaputra delta meets the Bay of Bengal, ranks among the most ecologically fragile and socially exposed coastal landscapes in the world. This study presents an integrated coastal vulnerability assessment of the South 24 Parganas district of West Bengal, combining remote sensing, GIS, pre-classified land use/land cover (LULC) data, and elevation-based flood modelling across three reference years — 2017, 2021 and 2025. Three linked objectives guided the work: building a Coastal Vulnerability Index (CVI) from elevation, slope and land-cover inputs through a weighted overlay in Google Earth Engine; tracking land-cover change across the three years using the Dynamic World product; and simulating flood extent and depth under three sea-level scenarios (S0: 2.8 m, S1: 3.3 m, S2: 3.8 m) using a digital elevation model. By 2025, Low (27.67%) and Moderate (24.02%) classes dominated the CVI map, while Very High vulnerability still covered 12.50 percent of the area (960.82 km²). LULC change detection found that 17.95 percent of the district (1,376.95 km²) shifted category at least once between 2017 and 2025. Flood modelling placed 21.09 percent of the district (1,617.02 km²) within reach of extreme high tides today, rising to 36.23 percent (2,778.01 km²) once 0.5–1.0 m of additional sea-level rise is factored in. Together, these results offer a practical evidence base for coastal adaptation planning and disaster risk reduction in one of the world's most climate-exposed deltas.
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