USA: How Phoenix is working to beat urban heat
By Keridwen Cornelius
So Phoenix has launched two revolutionary initiatives: HeatReady—the nation’s first program of its kind—treats heat readiness like hurricane readiness and heat waves like temperature tsunamis. It will alert residents with text notifications and offer emergency cooling centers. Another project, Nature’s Cooling Systems (NCS), is redesigning those low-income neighborhoods hit hardest by heat to remove some of the sting. Both programs emphasize close cooperation with residents and could provide a model for other cities. “Phoenix is definitely on the forefront,” says Melissa Guardaro, a research fellow at Arizona State University’s (A.S.U.) School of Sustainability. Heat, she adds, “is a huge public health concern.”
Shade trees are the most natural solution. In a desert city like Phoenix, that might mean planting mostly drought-tolerant native trees that cast light, lacy shadows—and interspersing them with leafier, thirsty trees where people can congregate, says Guardaro, who is part of the NCS team. Phoenix is ramping up efforts to meet a 20-year goal set in 2010 of achieving 25 percent tree canopy coverage, which will reduce temperatures nearly 8 degrees compared with bare areas.
NCS is also considering architectural measures such as shadow-casting art pieces that, without the need for water, could beautify barren neighborhoods, as well as orienting new buildings so they bathe sidewalks and courtyards in blocks of shade. Architects are additionally contemplating a return to traditional materials such as adobe as well as courtyards featuring evaporative cooling towers and trees—which together could cool buildings by up to 30 degrees—says Maggie Messerschmidt, urban conservation program manager at The Conservancy’s Arizona chapter. Solar panels could also be positioned over parking lots, where they would shield sizzling blacktop and prevent cars from turning into mobile furnaces, Guardaro says.
The HeatReady program also engages residents by asking them where cooling centers should be located. “We were able to get a lot of really important data from them,” says Chief Service Officer Michael Hammett; this included the need for cooling centers that allow pets and the idea to install misting systems and rotating blinds at bus shelters.