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Cool Roofs Studies are in the News

Posted by karen-smith-murphy on July 11, 2014

New reports from GCCA & ACEEE, and the Georgia Institute of Technology find that many cities are developing strategies to reduce excess urban heat, and that states, neighboring jurisdictions, utilities, and building owners are helping to mainstream these practices.

The first study comes from the Global Cool Cities Alliance (GCCA), and the American Council for an Energy Efficient Economy (ACEEE), in which they surveyed the policies of 26 North American cities.   E & E Publishing’s ClimateWire raised a few points we thought were worth noting, in Cities Take Steps to Address Extreme Heat

Several cities across the United States and Canada are now taking steps to mitigate local heat and prevent future warming, according to a new survey by the American Council for an Energy-Efficient Economy (ACEEE) and the Global Cool Cities Alliance (GCCA).  Of 26 medium and large cities, two-thirds cited extreme heat events and an increased number of high-heat days as the trigger for adopting policies to address the heat island effect.

. . .

Installing reflective and light-colored surfaces on walkways, roads and roofs is one of the most effective ways to address the heat island effect.  For instance, U.S. EPA research shows that conventional asphalt can reach 120-150 F in the summer, while reflective pavement stays 50-70 degrees cooler.

. . .

More than half of the 26 cities surveyed said they have requirements in place for reflective and vegetated roofing on private-sector buildings.  And nearly every city had policies to increase tree canopy and improve stormwater management.

ClimateWire also reported on a new study out of the Georgia Institute of Technology in which researchers looked at Phoenix, AZ, Philadelphia, PA and Atlanta, GA, and found that white roofs, reflective pavement and trees can counteract temperature increases in cities and save lives.   From Rising Temperatures Are Deadly, But Urban Cooling Fixes Can Counter Threats

[T]he researchers modeled how the three cities would respond to a minimum green space ratio on land parcels, setting a floor for areas covered with grass, gardens or trees. Vegetation tends to have a cooling effect by circulating moisture in the air that draws away heat during evaporation. Tree canopies also provide cooling shade.

The team also modeled how Phoenix, Philadelphia and Atlanta would behave with more reflective streets, sidewalks, parking lots and rooftops. Higher reflectivity, or albedo, means the area absorbs less sunlight, thereby lowering the temperature.

Stone and his collaborators then overlaid a health impact model. They found that combinations of increased vegetation and albedo could cut into projected increases in heat deaths, reducing them between 40 and 99 percent. “On average, we reduced the rate of increase by about 60 percent,” Stone said.

. . .

Groups like the Global Cool Cities Alliance are now trying to get cities to adopt these adaptation strategies, pitching them as a way to protect public health. However, it’s slow going, given that cities around the country address heat vulnerability differently, if at all.

You can find the full study HERE.

This report parallels a recent GCCA report, which looks at Baltimore MD, New York, NY, and Los Angeles, CA, and shows how reflective roofs and vegetation can cool air temperatures and save lives.

Note: Access to the ClimateWire articles is limited to subscribers.

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