Bangladesh is one of the most climate-sensitive countries globally, creating significant challenges for future development. Here we apply an integrated assessment model — Delta Dynamic Integrated Emulator Model (ΔDIEM) — to the south-west coastal zone of Bangladesh to explore the outcomes of four contrasting and plausible development trajectories under different climate and socio-economic scenarios: (1) embankment rehabilitation; (2) build elevation via controlled sedimentation; (3) planned migration (managed retreat) and (4) ‘do nothing’ (unplanned migration and abandonment). Embankment rehabilitation reduces flood risk, but at a high economic cost and enhancing waterlogging. Planned and unplanned migration combined with limited infrastructure management and governance both result in significant abandonment. Building elevation through sedimentation has the potential for increased environmental and economic sustainability but raises equity issues. Poverty and inequality persist across all scenarios, and outmigration from the coastal zone continues, although the magnitude is sensitive to assumptions about sea-level rise, socio-economic development and development trajectory. Integrated assessment tools linking the environment, people and policy choices, such as the ΔDIEM used here, highlight the complex interactions occurring in a dynamic delta environment. Such analysis supports informed management, development and adaptation.

中文翻译：

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到本世纪末，孟加拉国沿海地区的发展轨迹截然相反

孟加拉国是全球对气候最敏感的国家之一，对未来的发展提出了重大挑战。在这里，我们将综合评估模型-三角洲动态综合仿真器模型（ΔDIEM）-应用于孟加拉国的西南沿海地区，以探索在不同气候和社会经济情景下四种相反且合理的发展轨迹的结果：（1）路堤复原; （2）通过控制沉降来建立高程；（3）有计划的迁移（管理性撤退）和（4）“什么都不做”（无计划的迁移和放弃）。路堤的修复减少了洪水的风险，但付出了高昂的经济代价并增加了涝灾。计划内和计划外的迁移，再加上有限的基础架构管理和治理，都会导致大量废弃。通过沉降使建筑物高程具有提高环境和经济可持续性的潜力，但会引发公平问题。在所有情况下，贫困和不平等现象依然存在，并且沿海地区的移民活动仍在继续，尽管其程度对有关海平面上升，社会经济发展和发展轨迹的假设很敏感。链接环境，人员和政策选择的集成评估工具（例如此处使用的ΔDIEM）突出显示了动态三角洲环境中发生的复杂相互作用。这种分析支持知情的管理，开发和适应。尽管幅度对海平面上升，社会经济发展和发展轨迹的假设敏感。链接环境，人员和政策选择的集成评估工具（例如此处使用的ΔDIEM）突出显示了动态三角洲环境中发生的复杂相互作用。这种分析支持知情的管理，开发和适应。尽管幅度对海平面上升，社会经济发展和发展轨迹的假设敏感。链接环境，人员和政策选择的集成评估工具（例如此处使用的ΔDIEM）突出显示了动态三角洲环境中发生的复杂相互作用。这种分析支持知情的管理，开发和适应。