Mitigation of the urban heat island effect from rooftops

Abstract

The intensification of the urban heat island effect is an environmental and health problem that increases air temperature, summer energy demand, and heat stress. This study focuses on mitigation measures involving roofs due to their scalability and high surface availability. An exploratory and critical literature review was conducted, with a systematic search of indexed databases (mainly Scopus and Web of Science, as well as complementary sources), covering the period 2000–January 27, 2026, with eligibility criteria for empirical studies, modeling, and reviews with quantitative results, standardized extraction, and quality/bias risk assessment adapted to the type of evidence. The synthesized findings show that cool roofs consistently reduce surface temperature (typically 8–20 °C in summer) and generate measurable decreases in urban air temperature; at the city scale, a 0.1 increase in average roof albedo is associated with approximate reductions of 0.1–0.33 K, in addition to significant decreases in cooling loads and peak load. Green roofs provide thermal attenuation through evapotranspiration and hydrological co-benefits (retention and runoff delay), but their performance depends on substrate, moisture/irrigation, and maintenance. It is concluded that both strategies are complementary and should be prioritized according to climate, urban morphology, fraction intervened, life cycle costs and co-benefit targets, with an emphasis on maintenance and a focus on “hot spots” and vulnerable populations.