A Systematic Review on Synergistic Ecosystem-Based Adaptation for Sustainable Coastal Zone Management in Bangladesh

The coastal region of Bangladesh is among the most climate-vulnerable landscapes in the world where accelerating sea level rise, more frequent cyclone disasters and salinity intrusion are threatening millions of livelihoods and important ecosystems. Conventional gray infrastructures have performed inadequately as the only adaptation tool for coastal management in Bangladesh. This paper provides a critical synthesis of ecosystem based adaptation (EbA) for sustainable coastal zone management in Bangladesh highlighting the essence of a paradigm shift toward integrated approaches balancing human needs with ecological integrity. It explicitly quantifies performance trade offs across the green gray infrastructure continuum, analyzes uncertainty ranges in blue carbon uptake and proposes a spatially explicit decision framework linked to coastal hazard exposure zones. The prospects of multifunctional green-gray hybrid infrastructure in Bangladesh are critically reviewed through systematic review of empirical studies, geospatial analyses and project evaluations. A systematic literature search of academic databases was followed by thematic synthesis of forty four selected articles. Existing evidence indicates that mangroves can achieve up to sixty six percent wave attenuation within one hundred meter wide belts. Macroalgal beds show the highest per area carbon uptake (200 gCm⁻²yr⁻¹) but with the highest uncertainty estimates (±50%). Potential green gray infrastructure development opportunities in Bangladesh must therefore prioritize mangrove restoration and tidal marsh conservation as the reliable blue carbon pathways in the near term, while treating macroalgal systems as research pilots. Strategically designed hybrid approaches combining reinforced embankments with vegetated foreshores, low profile permeable breakwaters and community-based management can ensure better cost-effectiveness and resilience if implemented with context specific institutional coordination. However, implementation barriers include institutional fragmentation, monoculture plantation practices, insufficient long term monitoring and quantification of co-benefits. Therefore, an evidence-based and context-sensitive framework is recommended for integrating ecosystem-based adaptation with engineering interventions based on revised technical standards, function-based payment for ecosystem services and multiscalar governance mechanisms.