<p>Climate change poses existential dangers to sustainable development of Bangladesh with risks of erosion, a deltaic nation with unusual vulnerability in view of population density, agricultural economy, and low-lying terrain. So, the pressing need to address climate-related issues that pose serious risks to sustainability and jeopardize lives, ecosystems, and food security drive this research. While there is prior literature that specifically focuses on certain climate impacts, this study addresses the environmental degradation, socioeconomic vulnerability, and policy lag by system-dynamic causal model under mixed-method approach. The semi-structured interviews with policymakers and local inhabitants and stratified random household survey were used to collect data from climate-vulnerable coastal areas in the southeast region. The inferential statistics like, time series, regression and chi-square test were utilized to identify the impacts and climate change vulnerability. Furthermore, this study advises resilience planning and adaptation measures with lessons from the other South Asian coastal regions and other climate–vulnerable countries. Undoubtedly, these findings offer a replicable model for situating SDGs with localized adaptation to climate change, enabling policymakers to decrease transgenerational poverty while safeguarding ecosystems in terms of effectual strategies for a climate-resilient future in these deltaic regions.</p>