Operating the perfect cooling center is harder than it looks
In rural Ajo, Arizona, temperatures topped 100F (38C) every single day in June and July. For most of that time, the only spot within roughly 40 miles offering a free air-conditioned refuge was the local library — and that was only Monday through Friday. But on Aug. 3, Ajo celebrated the grand opening of its first “COOLtainer,” a repurposed shipping container outfitted with solar panels, a battery, AC, and seating. Arizona’s COOLtainer program has deployed 15 such containers since launching this year, with another three on the way. The one in Ajo brings Pima County’s tally of cooling centers to 39, and will help fill gaps in cooling capacity: It’s open on weekends and during power outages. In the face of rising temperatures, cities from Athens to Miami to Tokyo are increasingly embracing cooling centers — often indoor, air-conditioned public spaces that are activated during extreme heat. The need has never been greater: Thanks in large part to human-caused climate change, this year is on track to be the hottest ever. But crafting the perfect cooling center isn’t as simple as cranking the AC. Leaders like Arizona are learning that success often depends on tapping into community networks, making cool spaces as accessible as possible, and location, location, location. year,” says David Hondula, director of heat response and mitigation for the city of Phoenix. “We believe — and we think the data supports the notion — that access to cool space and water is life-saving.” On paper, Chicago in July 1995 seemed like the perfect cooling center use case. During a five-day heat wave, temperatures hit 106F and the heat index — how hot it actually feels — hit a staggering 125F. More than 700 people died. But while Chicago opened a handful of cooling centers, “very few people used them,” says Eric Klinenberg, a sociology professor at New York University and author of Heat Wave, about the 1995 event. “The population that needs them most — the elderly, the isolated, the poor — is also least likely to know they exist, and they are often hard to reach for that population on dangerously hot days.” A few decades later, getting people to show up remains a challenge. When Los Angeles experienced a deadly heat wave in September 2020 — admittedly, during a global pandemic — fewer than 300 people used the city’s six cooling centers. When heat emergencies hit New York City and Washington, D.C. this month, Bloomberg Green reporters visited a dozen cooling centers across both cities and found that some hadn’t seen a single visitor all day. The main exception were libraries, where several people confirmed they’d stopped by to escape high temperatures. Among the hurdles is a simple lack of awareness. Up until a few years ago, many people “didn’t know what a cooling center was or that it was available to them,” says Quinn Adams, a PhD student working on environmental health at Boston University. Location is another challenge. Because they often use existing infrastructure, “many cooling centers aren’t strategically placed,” says Michael Allen, an associate professor of geography at Towson University. Last year, Allen and his colleagues mapped 1,433 cooling centers across the US Southeast. They found that only 36% of the region’s population — and fewer than 10% of the most vulnerable groups in most states — lived within a 15-minute drive of one. As temperatures rise, many government officials are launching or revisiting their cooling center strategies. Chicago put more resources into its centers following the 1995 heat wave. Pima County has added cooling centers and expanded access to them in recent years, including by launching an interactive map that helped the county identify Ajo’s need for one. Japan is pushing local governments to set up cooling centers to reduce incidents of heat stroke, the most serious type of heat illness. As of July 30, at least 740 governments had done so — up from 139 in 2023 — according to the nation’s environment ministry In India, where 1.4 billion people face increasingly dangerous heat, several local governments have published heat action plans that call for cooling centers. But “no such dedicated facilities have been built on the ground,” says Avikal Somvanshi, head of the Urban Lab at India’s Centre for Science and Environment. Earlier this year, nonprofits Mahila Housing Trust and NRDC India took matters in their own hands, debuting a cooling station in the north Indian city of Jodhpur that’s powered by solar panels. Fans and misters provide the cooling, along with a special roof designed to maximize air flow. Abhiyant Tiwari, health and climate resilience lead at NRDC India, calls it “the first of its kind.” There is no one-size-fits-all cooling center. Some, like the COOLtainers, are movable. Many make use of existing facilities, including senior centers in Tokyo, libraries in London and mosques in Delhi. Some are only open on the hottest days, while others are accessible all summer. Some simply offer fans or AC, while others have water, snacks, towels, seating or places to lay down. Arizona’s Maricopa County, home to Phoenix, is arguably the world leader in cooling center strategy. The region has been expanding its network of them for roughly 20 years, and Hondula says there is now more funding, staffing and data collection than “anything I can remember over about 10 years of involvement.” The county offers three tiers of cooling facility: hydration stations with free water, cooling centers for a short rest, and “respite centers” for longer and sometimes overnight stays. Phoenix alone has more than 100 private- and governmentrun cooling facilities, including five city-owned sites with extended hours. As of this year, Hondula says the locations with extended hours all have dedicated staff and security, and by Aug. 7 had received more than 20,000 visits during their extended hours alone. “It’s a really large investment that we’re making that I know the city hasn’t made for this purpose in the past,” he says. Still, research on how effective cooling centers are at protecting people from heat is sparse. The Biden administration highlighted this knowledge gap in its new National Heat Strategy, which lists research on cooling shelters as a priority. In one study published in 2022, Adams and other academics found that “an unfeasibly large number of people would have to visit these centers in order to actually reduce the number of observed heat-related deaths.” Hondula and his colleagues used the same methodology to show that, in Maricopa County at least, cooling centers are more effective at saving lives when it comes to people experiencing homelessness. “I’m never going to say cooling centers shouldn’t happen — they absolutely should,” says Sarah Henderson, scientific director of environment health services at the British Columbia Centre for Disease Control. “But it can’t be what we’re hanging our hat on to protect people during extreme heat events.” Glen Kenny, a physiology professor at the University of Ottawa, is also among those seeking more intel. Kenny studies heat impacts on the body, and used heat wave simulations to determine that a few hours in a cooling centers can reduce core body temperature and heart strain among elderly people exposed to extreme heat. But he also found that their body temperature spiked to pre-cooling levels within two hours of leaving air conditioning, putting people at risk of overexerting themselves just when they think they’re in the clear. “What would be the natural tendency of somebody coming out of a cooling center? ‘I feel great,’” Kenny says. “‘I’m maybe going to do my groceries, go for a walk, maybe do stuff around the home and clean up.’ I’m going to do things that I really shouldn’t do.