America’s hottest city keeps getting hotter: How Phoenix is battling extreme heat
On a recent weekday afternoon in Phoenix, as the temperature soared to 108 degrees Fahrenheit, David Hondula—the city’s first director of its new Office of Heat Response and Mitigation—headed outside.
“We’re on our way right now to do some heat relief outreach this afternoon,” he said as we talked on the phone. “We try to catch the hottest part of the day, which is coming up here momentarily.” The team was looking for unhoused residents who might not know about local resources like cooling centers and free rides to reach them.
It’s one part of Phoenix’s response to a major challenge: Climate change is making America’s hottest city even hotter. Earlier this month, temperatures rose above 110 degrees for five days in a row; nighttime temperatures also stayed dangerously high. Average temperatures in the city are now 2.5 degrees hotter than they were in the middle of the last century. It isn’t just uncomfortable; it’s deadly. Last year, in Maricopa County, where Phoenix sits, there were 338 deaths associated with extreme heat. One hundred thirty of the people who died were homeless. The problem will get harder to address; by 2050, as climate change progresses, Phoenix could feel more like Baghdad, with some summer days hotter than 120 degrees.
The heat office, launched last fall to focus both on immediate responses to extreme heat and longer-term solutions to help cool the city down, is bringing together work that was previously happening across departments and didn’t have a single point of accountability. “It’s very important to have a citywide look so that we can find solutions, whether it be in the built environment or how we manage open space,” says Mayor Kate Gallego, who was elected in 2019 after campaigning on a sustainability platform. She also sees the opportunity for the city to become testbed for new technology to help with heat. “I want Phoenix to be the place where innovative companies with a solution to climate change come,” she says.
The city now has dozens of miles of “cool pavement,” streets treated with a reflective coating that an Arizona State University study found could lower the temperature of the surface by as much as 12 degrees compared to asphalt, and make the air above the ground cooler at night. Another program adds reflective coatings to roofs, which also helps reduce the need for air conditioning. Phoenix is also beginning to plant more trees in neighborhoods that have the least shade now, using a tree equity tool from the nonprofit American Forests to target the places most in need. “We’re trying to map ‘cool corridors’ in the locations where they’ll benefit the most people,” says Gallego. In April, city workers and volunteers planted 259 trees in the first of these corridors, on a route that students use to walk to school. A $6 million allocation from the American Rescue Plan will be used to plant more trees.
A combination of these changes can have a measurable impact. Climate modeling studies “suggest that with widespread deployment of cooling strategies, like cool roofs, and increasing the urban tree canopy, we can have a Phoenix of the future that is cooler than the one we have today, even as global warming continues,” says Hondula. “So the opportunity is very, very significant.” Some other factors can also help, he says, including a shift to electric cars or bikes, since gas cars generate heat. Everything is interrelated: If streets are shaded and comfortable enough for walking or waiting for public transit, people may also be less likely to drive short distances.
To deal with blistering heat now, the city has a network of cooling centers that open in May and stay open throughout the summer; as the hot season lengthens, some advocates are pushing to keep them open through October. (In other cities, cooling centers typically only open during heat waves.) If someone walks into a public library, they can get a bottle of water and a cooling towel while they sit in the air conditioning. At the Human Services Campus, the site of a group of local homelessness organizations, tents with evaporative cooling offer shade outside during the day.
Finding systemic solutions to homelessness is critical, since someone living on the street or in a car is most at risk from extreme heat. But it’s also important to find ways to help lower-income families who have air conditioning but can’t always afford to use it. “It becomes the choice between two really bad choices,” says Melissa Guardaro, a professor at Arizona State University who studies adaptation to extreme heat. “‘Do I pay for air conditioning, or do I pay for rent? Do I not pay for air conditioning, and then I know my kids going to have an asthma attack, and I’m going to have these medical bills?’ I mean, it’s just a catastrophe.”
In one program, the city worked with the local electric utility to install solar canopies over parking at a public housing complex; the electricity generated from the solar panels helps give residents a $15 discounts on their electric bills, while the panels also offer shade. “When we did our Climate Action Plan, our residents said they think about climate change on a daily basis,” Gallego says. “They also really pushed us to find solutions to reduce greenhouse gas emissions that help people save on their bills.” The city also helps residents make their homes more efficient, which can dramatically cut the amount of energy needed for air conditioning. Low-income residents can also get free trees to help shade their homes.
As climate change makes other cities hotter—and with extreme heat already responsible for more deaths each year than any other type of weather-related disaster in the U.S.—some cities are turning to Phoenix for advice. When an unprecedented heat wave hit the Pacific Northwest in 2021, Gallego got calls from several communities asking how to set up cooling centers. Phoenix can also offer advice about how to build infrastructure that can survive in extreme heat.
More cities are also likely to set up departments focused on heat, but even when that isn’t feasible, Hondula says it’s helpful to make it clear where the primary responsibility lies. Already, in the first months of existence for the new Office of Heat Response and Mitigation, “colleagues of mine have been bringing us ideas that they’ve just never perceived it to be their authority to be working on,” he says. In the past, it wasn’t clear where to go. “Is this the responsibility of public health, first and foremost? Is it really the responsibility of emergency management? Is it a human services problem?” he says. “Nationally, we just have not done a very good job of clarifying that responsibility. And with that ambiguity, I think it’s fair to say that we’ve had a lot of missed opportunities.”
It’s possible to eliminate deaths from extreme heat, says Guardaro. “This is something that is solvable,” she says. “But we just all need to start talking about it.”
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