C40 Good Practice Guide: Cool Cities

C40 Cities Climate Leadership Group has developed a series of eleven Good Practice Guides for reducing greenhouse gas emissions and climate vulnerabilities. The purpose of the Cool Cities guide is to summarize the key elements of launching and implementing successful cool surface programs. The success of C40 cities in planning and delivering cool surface solutions are highlighted in case studies.  

The good practices reviewed in the report include:

  • Make the cool surface business case to property owners
  • Incorporate cool options with other larger/long-term infrastructure projects
  • Undertake public outreach and awareness raising
  • Identify cooling co-benefits and pair with related projects
  • Offer incentives to implement cool solutions
  • Develop legislation requiring cool components

C40 is focusing on surface solutions to cool cities for many reasons including: 

Roofs and pavements cover about 60% of urban surfaces (with roofing covering 20–25% and paving covering about 40%), and absorb more than 80% of the sunlight that contacts them and is then converted to heat.

Depending on the city, a substantial portion of the remaining surface area of the city often presents an opportunity for parkland or other green landscaping.

Surface solutions are often readily deployable, simple, and cost-effective technologies available throughout the world.

The report provides detail on many strategies for addressing the urban heat index and cooling cities, along with case studies of successful implementation.  

For example, according to the report, incorporating cool infrastructure options with other larger or long-term infrastructure projects can provide easy opportunities to develop cool solutions. This can simplify the process of making a business case for cool solutions and securing funding. A related case study from Tokyo is provided on “Thermal-barrier Coating and Water-retentive Pavement.”

C40 also suggests that offering incentives (financial or non-financial) works well when the business case is not strong or otherwise financing cool surfaces is a barrier. Financial incentives can be direct, such as a subsidy or a grant, or indirect, such as a rebate. The Eco-Roof Incentive Program in Toronto is profiled as a case study for this strategy.



Publication Date: March 2016

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  • Best practice
  • Case study
  • Planning guides

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