Politicians and policymakers are worried about what increasingly extreme weather will mean for the health of communities. To face the problem, some cities have appointed “heat officers” or assigned similar officials to help adapt to the new reality.
Climate change will continue to intensify heat waves and droughts. Heat is known as the silent killer: Without the visual cues of other extreme weather events, such as floods and hurricanes, it can be difficult to recognize the health danger until it is too late.
Heat can be particularly deadly in cities. Dark roofs absorb heat and warm the buildings they cover. Glass from office-building windows reflects sunlight onto the streets below, where hard, dry streets and sidewalks streets bake in the sun. Narrow roads and tall buildings block cooling winds.
All of this contributes to the urban heat island effect, in which densely built urban areas with limited greenery become literal hot spots. In these “islands,” daytime temperatures are about 1 to 7 degrees Fahrenheit higher than those in outlying areas, and nighttime temperatures 2 to 5 degrees higher, according to the U.S. Environmental Protection Agency.
“We just didn’t build for these temperatures,” said Kathy Baughman McLeod, director of the Atlantic Council’s Adrienne Arsht-Rockefeller Foundation Resilience Center, which launched a project three years ago to encourage municipal or regional governments to designate chief heat officers, empowered to come up with innovative, local solutions. The initiative started in Miami-Dade County, where Jane Gilbert was appointed last year to the world’s first such post. Cities including Athens and Santiago followed suit.
Outside of this project, climate-focused officials in other cities are carrying out similar work to build cooler, more resilient metropolises.
Here’s how four world cities are trying to beat the heat.
Ancient architecture in Athens
Summer in Athens has been mild compared with last year, when a record-breaking heat wave brought triple-digit temperatures and wildfire smoke. But the Greek capital still got an opportunity to test a new early-warning system for heat waves.
Extreme heat, which is “totally invisible” and “pernicious,” is the main problem climate change has caused in Athens, said Eleni Myrivili, who was appointed the city’s first chief heat officer last year. (She recently became U.N. Habitat’s Global Chief Heat Officer.)
Working with the Arsht-Rock Center, Myrivili realized “it would be a game changer if we started categorizing heat waves.”
The city worked with a team of meteorologists to develop a model that could forecast heat waves based on past weather patterns. Using this data, Athens created a system that breaks heat waves into four categories according to their risk to human health.
When temperatures pitched the city into Category 1 this summer — the second-lowest, yet still dangerous, tier — city authorities sent out warning messages on social media and directly to residents’ phones, as well as to employees of organizations that work with vulnerable communities. City employees staffed a hotline for residents seeking help.
A separate project looks to the ancient past to try to bring about a cooler future. Built around 140 A.D., the Hadrian Aqueduct, named for the Roman emperor who commissioned it, has transported water through a 12-mile tunnel underneath Athens for nearly 2,000 years. The aqueduct was once a source of drinking water, but waste rendered the water unusable in recent decades, leading to large quantities of water being dumped into the sea.
Now, officials have a plan to use the water to irrigate a new vegetation corridor through the city. New green spaces, which also include mini “pocket parks,” will help lower temperatures by providing shade and moisture.
Heat shelters in Barcelona
Green space is a centerpiece of Barcelona’s efforts to keep people safe in extreme heat. It’s an increasingly pressing need in the bustling city in northeastern Spain, according to Eloi Badia, the deputy mayor for climate issues.
Elderly people, babies and people with respiratory issues are especially vulnerable in high temperatures, Badia said. In 2020, the city began creating a network of shelters to provide relief from the heat. Maps list the roughly 200 points across the city, some of which are indoor centers with air conditioning and staff trained to provide advice on health effects.
Parks and gardens with water fountains and plenty of shade are also on the list. Their number continues to grow as authorities add nearly 100 acres of green space to the city every four years.
Covered markets in Freetown
In Sierra Leone, climate change, including rising heat, is contributing to rapid urbanization. A large portion of the population depends on subsistence agriculture, and with farming conditions deteriorating, many people are relocating to cities.
But that migration is driving deforestation and making the heat problem worse, according to Eugenia Kargbo, the chief heat officer of Freetown, the West African country’s capital.
“You see the impact — it’s really, really visible. The only challenge that we have is that there is not much importance given to the situation,” she said.
Heat does not impact residents equally, and much of Kargbo’s work centers on protecting the most vulnerable. Thirty-five percent of Freetown’s population of 1.2 million lives in informal settlements that are ill-equipped for high temperatures. In newly urbanized areas, many women engage in informal trade, selling vegetables and fruits at one of Freetown’s 42 markets. More than a dozen of these markets are in open air, where women stand in the sun all day and “suffer immense loss” as their fresh produce perishes in the heat.
Kargbo is working with the Arsht-Rock Center to add shade cover to these markets, in a project that launched Friday. About 11,000 women — shoppers as well as vendors — will benefit, she said.
“The model makes use of a simple heat-resistant material to provide the shade, but also incorporates the installation of solar light,” Kargbo said.
Urban forests, green roofs in Santiago
With more than 8 million residents, Chile’s capital region is home to 40 percent of the country’s population. “Anything that happens here impacts a lot of people,” said Cristina Huidobro, the metropolitan area’s first chief heat officer, who is planning for the season to come as winter winds down.
The city, which has grappled with drought for more than a decade, is dotted with urban heat islands, many in low-income areas.
Poorer communities are also “more vulnerable to heat and all its impacts,” Huidobro said. “That’s why we are working to address that problem with a massive tree forest program next year.”
In addition to the $2 million urban forest program, the Santiago region is rolling out a green roof pilot project. Green roofs, which consist of a layer of vegetation planted on top of a flat or nearly-flat roof, absorb less heat than traditional dark roofing surfaces and provide insulation that reduces the amount of heat that seeps into the building.
First up in Santiago: 10,700 square feet of green roofing to be installed on top of a hospital.
Authorities chose the site partly as a gesture to health workers, who have been working extra hard during the pandemic, Huidobro said. But patients will also benefit, she added, because “it’s been proved that having green environs helps with the healing process.”