2026-07-06 オックスフォード大学
＜関連情報＞
- https://www.ox.ac.uk/news/2026-07-06-new-study-reveals-the-worlds-cities-most-at-risk-from-extreme-heat
- https://www.sciencedirect.com/science/article/pii/S2210670726004221
曝露を超えて：都市における熱リスク評価のための世界的に比較可能な枠組み Moving beyond exposure: a globally comparable framework for heat risk assessment in cities
Nethmi Jayaratne Kariyawasam, Jesus Lizana, Radhika Khosla
Sustainable Cities and Society Available online: 21 May 2026
DOI:https://doi.org/10.1016/j.scs.2026.107535
Highlights
- Exposure-only views of heat risk are systematically misleading.
- Over 95% of the highest-risk cities are concentrated in the Global South.
- UTCI-based Cooling Degree Days capture cumulative heat stress beyond air temperature alone.
- Component-resolved analysis reveals diverse urban heat-risk pathways, highlighting the need for spatially and socio-economically targeted adaptation strategies.
Abstract
Most global heat assessments rely on exposure-only indicators. However, heat risk in cities extends beyond climatic extremes and is mediated by social vulnerabilities and infrastructural capacities that determine how populations experience and respond to heat. Here, we map heat risk globally in cities with populations over one million using a harmonised composite index disaggregated into hazard exposure, vulnerability, and coping capacity. Hazard exposure is characterised using the population-weighted Universal Thermal Climate Index (UTCI)-based Cooling Degree Days, which capture cumulative heat stress. Vulnerability and coping capacity are characterised by economic capacity, demographic structure, and infrastructural factors. The results show that over 95% of the highest-risk cities are concentrated in South and Southeast Asia and Sub-Saharan Africa. They also demonstrate that exposure alone is insufficient to predict risk. Several highly exposed cities (e.g., Bangkok, Jeddah) rank lower due to strong coping capacity, while others (e.g., Karachi, Faisalabad, Kaduna) face severe risk under moderate exposure. Our component-resolved risk analysis also reveals within-region heterogeneity, highlighting the need for spatially resolved, socio-economically contextualised approaches to heat adaptation by reducing exposure, addressing socioeconomic vulnerability, and investing in infrastructure to advance urban heat resilience in a rapidly warming world.
