Assessment of erosion-accretion patterns, land dynamics, and climate change impacts on the islands of the south-central coastal zone of Bangladesh using remote sensing techniques

This study investigates morphological changes, erosion-accretion patterns, and climate change impacts on Bangladesh's dynamic coastal regions focusing on the Meghna Estuary and islands like Sandwip, Urir Char, and Swarna Dweep. Using remote sensing and GIS techniques, the research analyzes short-term (5-year) and long-term (30-year) changes from 1991 to 2021. Satellite imagery reveals significant erosion and accretion rates. Sandwip experienced high erosion (up to 29.48 km2 every 5 years) until 2006 but recent stability. Urir Char faced substantial erosion (up to 22.73 km2 every 5 years) until 2001 in the southeast and accretion in the north. Swarna Dweep showed minimal erosion but significant accretion. The islands exhibited migration tendencies: Swarna Dweep southeast, Sandwip northeast, and Urir Char northwest. Cyclones, including the 1991 event, Sidr, and Aila, significantly reshaped coastal morphology. Climate change impacts include increasing rainfall trends (up to 0.8572 mm/year on Sandwip), rising temperatures (up to 0.005 degrees C/year on Urir Char), and accelerated sea-level rise (up to 11.93 mm/year on Sandwip). The study emphasizes the importance of monitoring, coastal management, and adaptation strategies for Bangladesh's dynamic coastline in the face of ongoing environmental changes.