Abstract
Climate change-induced salinization (CCIS) poses a significant public health threat in low-elevation coastal zones like Bangladesh, degrading drinking water quality and contributing to adverse outcomes, including hypertension and reduced productivity. While these risks are increasingly documented, critical evidence gaps persist regarding effective, scalable interventions that foster the sustained adoption of safe water alternatives, particularly given behavioural barriers such as cost sensitivity and taste acclimatization. This project aims to fill this gap through a cluster randomized controlled trial (cRCT) in Khulna, Bangladesh, an area severely impacted by CCIS. We propose to experimentally evaluate an innovative intervention that combines subsidies for desalinated water with targeted information dissemination and behavioural nudges designed to promote habit formation. Key goals are to rigorously assess the intervention's effectiveness in achieving sustained safe water adoption post-subsidy, measure impacts on adult physical and mental health and child health outcomes, and generate actionable, cost-effectiveness evidence to inform policy. Findings will provide tangible evidence for community-level adaptation and health improvements on the ground, directly inform Bangladesh's critical National Adaptation Plan and Nationally Determined Contribution updates, and contribute a scalable, evidence-based model for addressing CCIS challenges in resource-constrained coastal regions throughout the Global South.