Unintended Consequences and Trade-Offs of Heat Mitigation Strategies

Globally, more people will be vulnerable to heat in the future considering the current trend of urbanization and climate change. Infrastructural heat mitigation strategies such as additional trees and vegetation, green roofs, cool roofs, cool pavements, and climate-sensitive urban form intend to cool the built environment and reduce heat morbidity and mortality, especially during heat waves. This review shows that heat mitigation strategies achieve the desired cooling effect, but unintended consequences and trade-offs of interventions, e.g. reduced air quality, have received less attention. These side effects might be detrimental, creating a negative long-term health impact for the local population. Combining strengths and weaknesses of different strategies needs more attention to reduce stressors and understand the meteorological/physical interactions to prevent unintended consequences. In addition, social and behavioral heat mitigation strategies should be considered to widen the spectrum of possible combinations. A more holistic approach of combined heat mitigation strategies will minimize unintended detrimental side effects on air quality and achieve the best improvements for urban dwellers during the hot season.