Year: 2026 | Month: April | Volume: 13 | Issue: 4 | Pages: 623-645
DOI: https://doi.org/10.52403/ijrr.20260465
Urban Heat Islands and Heat Waves as Compound Urban Warming: Mechanisms, Observation, Modelling, Health Risk, and Equitable Adaptation
Marcellino Christofel Mambu1, Weny J.A. Musa2, Marike Mahmud3
1,2,3Doctoral Program in Environmental Science, Gorontalo State University, Gorontalo, Indonesia.
Corresponding Author: Marcellino Christofel Mambu
ABSTRACT
Urban heat islands (UHIs) and heat waves (HWs) are no longer best understood as parallel hazards. Across diverse climates, urban forms, and development trajectories, they increasingly operate as a compound urban warming regime that intensifies thermal exposure, modifies boundary-layer processes, amplifies health risk, strains energy and water systems, and challenges urban governance. Building on the earlier systematic review of UHI–HW research and incorporating more recent literature from the supplied Scopus corpus, this review synthesizes advances in mechanisms, observations, modelling, vulnerability analysis, and adaptation. The evidence base shows that research has shifted from documenting whether UHI–HW synergy exists toward asking when, where, and why the synergy strengthens, weakens, or reorganizes across scales. Recent studies highlight the importance of urban morphology, anthropogenic heat, soil moisture, wind, humidity, vegetation structure, and background synoptic forcing in conditioning compound heat. Methodologically, the field has moved toward multi-source integration, including dense in situ measurements, citizen weather networks, geostationary and polar-orbiting satellites, local climate zone classification, high-resolution urban canopy parameterization, and coupled mesoscale–biometeorological modelling. The literature also demonstrates that compound urban warming is fundamentally unequal: exposure, sensitivity, and adaptive capacity vary sharply within and across cities, making equity-sensitive interventions essential. Mitigation studies confirm the potential of cool roofs, green roofs, trees, irrigation, and urban blue–green infrastructure, but they also reveal context-specific trade-offs involving humidity, ventilation, nighttime performance, and air quality. This review argues that the next frontier lies in integrated urban heat intelligence: city-scale systems that link urban climate science, health surveillance, fine-scale forecasting, and targeted adaptation. A future-ready research agenda therefore requires higher-resolution observations, better urban parameterization, stronger coupling of physical and social risk models, and implementation frameworks that prioritize both effectiveness and justice.
Keywords: urban heat island; heat waves; compound urban warming; heat-health risk; urban climate modelling; thermal remote sensing; equitable adaptation
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