Bye-Bye, Blacktop—Why White Streets Will Chill Our Boiling Cities

And you thought white roofs were cool?

Two researchers take the temperature of painted pavement in Berkeley, California. (Photo: Berkeley Media)
Sal holds a political science degree from the George Washington University. He's written about all things environment since 2007.

Move over, white roofs. There’s a new, chill player in urbanity: so-called cool pavement.

Researchers in California have engineered a reflective coating that, when applied to blacktop, can lower the surface temperature of a city boulevard or a parking lot by a whopping 40 degrees Fahrenheit on a sweltering summer day.

“Because dark pavements absorb almost all of the sun’s energy, the pavement surface heats up, which in turn also warms up the local air,” said Haley Gilbert, of Cal Berkeley’s Heat Island Group, to The Daily Mail.

Because they reflect light, and therefore heat, back into the lower atmosphere, light-colored surfaces have been shown in studies to reduce smog and, more importantly, lower energy costs in big cities.

Think of cool pavement as a very close cousin to white roofs, a movement that’s slowly—too slowly, if you ask me—sweeping the country.

As detailed in an op-ed for TakePart last month, Juan Carlos of the White Roof Project writes that “a roof covered with solar reflective white paint reflects up to 90 percent of sunlight as opposed to the 20 percent reflected by a traditional black roof.”

And, implementing a white roof program in just 11 large cities could save the U.S. 7 gigawatts in energy usage, or “the equivalent of turning off 14 power plants.”

Because the cool pavement movement is in its infancy, it really isn’t known exactly how much a painted avenue, say in Manhattan, would lower a city’s long-term temperature.

And the folks in Berkeley are still working out which light color will prove coolest. “Some likely perform better under vehicle traffic on city roads. Others may maintain solar reflectance better over time,” said Ben Mandel, a research assistant on the project.

If I had a vote, I’d paint cities green. Actually, that’s a white lie, since if I really had my way, I wouldn’t be advocating for urban painting but for urban planting instead.

You see, if we’re truly interested in sending urban heat islands to a permanent icy grave, mayors up and down and across the country should be greenlighting the planting of millions of city trees, opening more and more city parks, and planting more and more rooftop gardens and farms.

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