The coastal environment is impacted by various extreme cyclonic and human activities, whereas the Sundarban Biosphere Reserve (SBR) region is largely affected by tidal activities, cyclones, saltwater intrusion and factors associated with deforestation. The mangrove ecology, sea level rise (SLR) and shoreline change are all impacted by global climate change. The four blocks that were chosen for this study were Sagar Island, Namkhana, Kakdwip and Pathar Pratima. With the use of Earth’s observational remote sensing data, physical, biological and anthropological activities were produced. The main erosion affected and changes areas are located at 5.42 km2 (1991–2001), 5.48 km2 (2001–2011), 9.77 km2 (2001–2021) and overall, 20.67 km2 (1991–2021), where the accretion was high in Lothian Island, Half-fish Island and some parts of Sagar Island but the erosion located in many parts of this study area. The regions impacted by sediment deposition increased by 51.32 km2 (1991–2021), with the Diamond Harbour area being the most affected by SLR at a rate of 4.67 + 0.68 mm/year. In light of the aforementioned problems, the annual average chlorophyll concentration at the 0.623 leaf area declined by 0.298. The coastal areas, which are most impacted by biodiversity loss, were impacted by the extreme ecological disruption and population pressure. Researchers, scientists, planners and policymakers can also benefit from these study results for the sustainable development of this region.