Cool Policies for Cool Cities: Best Practices for Mitigating Urban Heat Islands in North American Cities

This survey by the American Council for an Energy Efficient Economy (ACEEE) and the Global Cool Cities Alliance (GCCA) reviews the urban heat mitigation activities of 26 cities in the U.S. and Canada – representing all of the major climate zones, geographies, and city sizes across North America. They found that heat waves along with other natural disasters and extreme weather has motivated nearly two thirds of the cities surveyed to initiate urban heat island mitigation strategies.

The urban heat island effect is a global phenomenon in which dark, impermeable surfaces and concentrated human activity cause urban temperatures to be several degrees hotter than those in surrounding areas. Urban heat islands impose negative effects on local and global public health, air quality, energy consumption, resilience, quality of life, stormwater management, and environmental justice.

Several best practices across diverse localities were found from the survey. A number of local governments are requiring the use of “cool roof” technologies, lining city streets with shade trees, and raising public awareness. Almost every city had policies to increase tree canopy and manage storm water. The report includes case studies on how several cities are managing urban heat, demonstrating a variety of response strategies.