Modified Roofs, More Green Spaces Among Steps to Cool Las Vegas’ Urban Heat Island
Sourced from the Las Vegas Sun
Climate scientist Ronnen Levinson travels from his home in Berkeley, Calif., to Las Vegas three or four times a year on business, and he says he’s often befuddled when he opens the curtains in his hotel room.
More times than not, he’s in a room that overlooks a roof outfitted with air conditioning equipment, and the material covering the roof is dark-colored.
Levinson leads the Heat Island Group at Lawrence Berkeley National Laboratory, a group that works to cool buildings, cities and the planet by making roofs, pavements and cars cooler in the sun. When he sees a dark roof, he wonders why more resorts — or building owners in Las Vegas in general — don’t repaint them to a lighter color, even if only to save on electricity costs.
Levinson is an expert on urban heat islands, which form when cities are mostly made up of pavement and buildings that retain heat, driving temperatures higher than they’d otherwise reach with no greenery or shade.
Las Vegas is an urban heat island and is one of the fastest-warming cities in the country, second only to Reno, according to the environmental nonprofit Climate Central.
“The thing that drives the difference in the temperatures of the city’s surfaces, its pavements, its walls, its roofs, is sunlight,” Levinson said.
Most painted buildings cast a diffused reflection that only reflects some light that hits it, while a mirrorlike reflection reflects it all. Levinson said roughly speaking, half will be reflected back up at the sky and half will be reflected down.
“The half that goes down will strike other surfaces, like other walls, or the ground, or people,” he said.
He said that’s more reason that buildings should be painted light colors or with paints designed to keep the surfaces cool.
“When you’re on the Strip … you’re trying to make a building that’s attractive, so you don’t want something as unexciting as an off-white wall,” Levinson said. “But there’s also a lot of flat roof areas doing nothing but holding air conditioning equipment, so there’s a certain irony to all of this.”
From the Living Architecture Monitor
