Above and Beyond: Integrating Building Height and Protection Standards in Global Flood Risk Assessment

Floods pose a significant global threat, causing widespread human and economic losses. However, current flood risk assessments frequently rely on simplified assumptions–such as uniform flood depth-damage relationships and country-level protection standards–that neglect crucial factors like building height and the spatial variability of flood defenses. These assumptions limit the accurate estimation of structural damage and local adaptive capacity, especially in densely built or poorly protected areas. Moreover, most assessments operate at course spatial resolutions, overlooking the fine-grain variability and heterogeneity that drive vulnerability at city and neighborhood scales. To address these limitations, this study introduces a comprehensive framework that integrates flood depth, building height, and protection standards across multiple scales—aggregating analyses from individual pixels to urban areas, countries, and world regions. Our new framework reveals that Southeast Asia accounts for the largest share of global flood-damage (42%), after considering building height and protection standards, rather than just the 3rd largest share (15%) when only flood-depth is considered. The findings, accessible through Google Earth Engine, provide actionable insights for guiding targeted interventions, enhancing resilience, and mitigating flood impacts in vulnerable areas.