If heat waves are the “new normal”, how can we cool down our cities?

While this may not come as a surprise to many people, official records now show that July was the hottest month ever recorded on Earth.

The annual mean temperature in the United States has already warmed over the past few decades and is expected to rise by 5°F to 8.7°F by the end of this century.

In July, the Biden administration launched Heat.gov, a new website providing clear information on understanding and reducing the health risks of extreme heat.

Extreme heat has been the number one weather-related cause of death in the US for the past 30 years – killing over 700 people a year.

Additionally, mortality from extreme heat disproportionately affects Native American and Black communities.

As policymakers grapple with how to deal with this “new normal,” several projects are underway to cool down cities and towns, which are often hotter than rural areas.

Some focus on nature-based solutions like living walls and green roofs, but one innovative project is being led by roofing and waterproofing manufacturer GAF, which is producing solar-reflective road and sidewalk coatings on a 10-square-block area in the Los Angeles neighborhood of Pacoima

The project covers roads, basketball courts, playgrounds and other surfaces with the coating, which reflects the sun’s infrared radiation that would normally be absorbed by asphalt.

Traditional forms of black asphalt absorb and retain more heat than natural surfaces.

At night, the asphalt releases heat back into the atmosphere. This can help keep temperatures high in built-up areas — sometimes referred to as the UHI (Urban Heat Island) phenomenon.

Jeff Terry, vice president of sustainability at GAF and project leader for the GAF Cool Community project, said the solar reflective coating can help lower surface temperatures, sometimes by between 10 and 12 degrees in the heat of the day, which ultimately helps to reduce the environment temperature also in the neighborhood.

Terry added that they chose the Pacoima block because it has a lot of hard surfaces and regularly records high temperatures throughout the year.

“It’s also a community that hasn’t invested a lot in cooling solutions compared to more affluent communities,” Terry said.

“This is a community where one in five people lives below or at the poverty line. So we also wanted to focus on awareness and education in a neighborhood that hasn’t received much attention to the effects of climate change and the city’s heat.”

Terry said installation of all new surfaces and coatings should be complete by early August and they will spend the next 12 months monitoring air and surface temperatures and the heat absorption rate of the new surfaces – often referred to as albedo.

Additional phases of the project may also include cool roofs and solar.

As part of this research, GAF has installed two rooftop weather stations in the neighborhood that will monitor a variety of factors including humidity, wind direction and incoming solar radiation.

To monitor street-level heat, a specially adapted golf cart with sensors will drive around the block, and satellite technology and drones will also be used to test how effective the new surface coatings are.

He added that the project worked closely with the community at every stage of the project.

“We have organized a whole series of community meetings where we have invited residents to come together and help them understand that we are not invaders. We want to be a part of their community with them throughout the year plus of this project,” he told Terry.

“We had an entire team that coated the local basketball court and created a really cool blue court in LA Dodger because that’s what the community wanted.

“When it was done we were having a community celebration and there was a little guy walking around the basketball court barefoot just about noon. There was no way he could have done that before. His feet would have been burned off,” he added.

“Our hope is not just to really help this one community, but that doing so will help create a model that will help city planners. This could give them an example of what works and show them why we need to invest in tackling urban warming.”

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