Articles | Volume 17, issue 14
Research article
27 Jul 2017
Research article |  | 27 Jul 2017

A wedge strategy for mitigation of urban warming in future climate scenarios

Lei Zhao, Xuhui Lee, and Natalie M. Schultz

Abstract. Heat stress is one of the most severe climate threats to human society in a future warmer world. The situation is further exacerbated in urban areas by urban heat islands (UHIs). Because the majority of world's population is projected to live in cities, there is a pressing need to find effective solutions for the heat stress problem. We use a climate model to investigate the effectiveness of various urban heat mitigation strategies: cool roofs, street vegetation, green roofs, and reflective pavement. Our results show that by adopting highly reflective roofs, almost all the cities in the United States and southern Canada are transformed into white oases – cold islands caused by cool roofs at midday, with an average oasis effect of −3.4 K in the summer for the period 2071–2100, which offsets approximately 80 % of the greenhouse gas (GHG) warming projected for the same period under the RCP4.5 scenario. A UHI mitigation wedge consisting of cool roofs, street vegetation, and reflective pavement has the potential to eliminate the daytime UHI plus the GHG warming.

Short summary
Heat stress associated with climate change is one of most severe threats to human society. The problem is further compounded in urban areas by urban heat islands (UHIs). We use an urban climate model to evaluate the cooling benefits of active urban heat mitigation strategies both individually and collectively. We show that by forming UHI mitigation wedges, these strategies have the potential to significantly reduce the UHI effect plus warming induced by greenhouse gases.
Final-revised paper