Urban Heat Resilience: Bridging Science, Policy, and Sustainable Design, Flagship Report

Bangkok, like many rapidly urbanizing cities in Southeast Asia, faces an escalating threat from extreme urban heat, exacerbated by the urban heat effect and global climate change. This challenge disproportionately affects vulnerable communities, including women, children, the elderly, persons with disabilities, low-income households, and informal settlement residents, who often lack adequate adaptive capacity and resources. This report, drawing from the "Urban Heat Resilience: Bridging Science, Policy, and Sustainable Design" project, presents a comprehensive analysis of urban heat risks in Bangkok and the potential of Nature-Based Solutions (NBS) as a key mitigation strategy. Building on this, the report also incorporates specific findings and policy insights from the Vietnam Urban Heat Status report, detailing observed temperature shifts, urban heat island effects, health impacts, and policy landscapes within Vietnamese cities, offering learnings applicable to second-tier Mekong cities in Vietnam. Utilizing the TARGET urban climate model, simulations for both present-day (1985-2014) and projected mid-century conditions (2036–2065) demonstrate that central and western districts with high imperviousness experience the greatest heatwave burden, with up to 100 heatwave days per season, lasting weeks at a time, and with significant thermal intensity. Without intervention, many districts could see an additional 40–60 heatwave days per year by mid-century. Nature-Based Solutions (NBS), which involve widespread increases in pervious, green, and irrigated surfaces, particularly in highly impervious areas, are projected to significantly mitigate these impacts. The NBS scenario suggests a reduction of up to 24 heatwave days in hotspots, shorter heatwave events (over 30 days reduction in duration in some areas), and meaningful reductions in heatwave severity (up to 0.4°C during extreme events). These benefits are spatially consistent with intervention areas, highlighting the strong local cooling effects and spillover benefits of NBS. Crucially, the project emphasizes a Gender Equality, Disability, and Social Inclusion (GEDSI) Action Plan to ensure that heat resilience efforts are inclusive and equitable. This plan integrates GEDSI principles into all project phases, from data collection and policy design to implementation and monitoring, prioritizing the needs of vulnerable populations. While NBS offers a substantial buffer against climate-driven urban heat, it is not a standalone solution. A comprehensive, multi-layered adaptation strategy is required, combining NBS with broader systemic measures such as inclusive heat alert systems, cooling centers, hydration points, and integrated urban planning and policy that accounts for social equity. This project aims to bridge the gap between scientific understanding, policy frameworks, and practical implementation to build a more heat-resilient, equitable, and livable Bangkok, with learnings applicable to other Mekong cities in Vietnam.