Sea level rise along the coast of Bangladesh under different climate scenarios

The low-lying coastal plain of Bangladesh is highly vulnerable to flooding, sea level rise (SLR), and vertical land motion. Tounderstand SLR dynamics, IWM, in collaboration with the UK Met Office, conducted a comprehensive study analyzing zonal and seasonal variations under different climate change scenarios. The research also examines the influence of freshwater inflows from the Ganges, Brahmaputra, and Meghna basins on local SLR. Using the MIKE modeling system - comprising the Basin Model, National River Model, and Bay of Bengal Model - the study simulated basin flows and seasonal variations under various greenhouse gas emission scenarios. The National River Model generated boundary flows and water levels for the Bay of Bengal Model, which estimated SLR along the coastline. Results show that future precipitation and temperature changes will significantly affect river flows, especially during winter when increased precipitation drives higher runoff. Under medium and high emission scenarios, projected SLRs are approximately 0.19 m and 0.32 m by 2045 and 2061, and 0.46 m and 0.61 m by 2093 and 2090, respectively, compared to 2006. Regional projections for three Bangladeshi coastal locations range between 0.14 m and 0.74 m, slightly lower than the global range of 0.17 m to 0.84 m. The findings align with Bangladesh Delta Plan estimates (0.2-1.0 m by 2100) but indicate less variability in the northern Bay of Bengal compared to global projections. This study underscores the critical need for integrating localized SLR dynamics into coastal management and adaptation planning for Bangladesh.