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Cities+Nature

Every city needs a ‘chief heat officer’

Global warming often takes a back seat to other crises. In Sierra Leone, it's one woman’s full-time job.

By Ryan Lenora Brown

The new buildings sprouted like weeds, clinging to hillsides and rising in the cracks between houses. In many neighborhoods, tin roofs on shacks were so densely packed, they resembled a game of Tetris. Everywhere Eugenia Kargbo looked, Sierra Leone’s capital, Freetown, seemed to be devouring itself.  

For years, Kargbo had watched her hometown grow denser and denser, hotter and hotter. Freetown, situated on a peninsula that juts into the Atlantic Ocean, had always been balmy. But in recent years, migrants — many fleeing failing crops and other effects of climate change — have flooded into Freetown. The city, home to just over 1 million people in 2015, has an estimated 1.27 million today. And as the population swelled, trees came down to make room for houses, average temperatures ticked upward, and residents began complaining that the heat had become unbearable.

Now, as Freetown’s first-ever “chief heat officer,” Kargbo has a chance to be part of the solution. “The problem is quite invisible,” she says. “People say, ‘Oh, it’s Africa, oh, it’s the tropics,’ but that hides how much of a problem heat has become.”

When people think of extreme weather, they often think of singular catastrophes: hurricanes, tornadoes, blizzards. But based on death rates, heat waves are the single most dangerous weather events — and because of climate change, they’re rapidly getting worse. Globally, deaths caused by high temperatures have risen 74% since 1980, according to a 2021 study published in the medical journal Lancet. Earth recorded its hottest-ever average month in July 2021. And in June of this year, heat waves were already breaking temperature records across the U.S., leading meteorologists to predict another sweltering summer.  People in cities, where temperatures are routinely several degrees hotter than surrounding areas, are at particular risk.

But because heat is far less visible than other kinds of extreme weather, it has long been difficult to drum up resources to fight.

“In a lot of governments, you have an agency for natural disasters. We name storms. We have seasons for hurricanes, fires, and monsoons. But there are rarely people working specifically on extreme heat,” says Kathy Baughman McLeod, director of the Adrienne Arsht-Rockefeller Foundation Resilience Center at the Atlantic Council in Washington, D.C.

Extreme heat, McLeod and her colleagues decided, needed a dedicated PR team. So last year, the organization asked cities to appoint officials whose jobs focus solely on blunting the effects of extreme heat — a position it catchily titled the “chief heat officer.

“In a lot of governments, you have an agency for natural disasters. We name storms. We have seasons for hurricanes, fires, and monsoons. But there are rarely people working specifically on extreme heat.”

Kathy Baughman McLeod, the Atlantic Council

McLeod says the organization came up with the program in collaboration with Miami-Dade County Mayor Daniella Levine Cava, a longtime advocate for cities on the forefront of climate change. Arsht-Rockefeller pledged initially to sponsor one so-called “CHO” on each continent — providing what it terms “modest” startup capital for the positions (the center wouldn’t provide exact figures) and technical support.

Today, Miami-Dade County, Athens, Santiago, and Monterrey, Mexico, also have so-called CHOs through Arsht-Rockefeller. Phoenix and Los Angeles have appointed similar officials of their own accord. Since November, Kargbo, a former banker, has been Freetown’s.

What CHOs do depends largely on where they are. In sweltering Western cities like Miami — whose professional basketball team is aptly called the Heat — the job might entail improving access to air-conditioning, retrofitting buildings to be cooler, and advocating for heat waves to be given names, as hurricanes are. (Seville, Spain, recently announced it would begin doing so, and Miami-Dade is piloting a program to categorize heat waves by severity.)

But in a coastal African city like Freetown, where heat is already tearing through the lives of some of the world’s poorest people, the work has an added urgency.

“Countries like [ours] do not have the resources we need to really drive the change,” says Kargbo. “But we’re the ones already suffering.”

Because places like Freetown were warm to begin with, a rise of a few degrees can be the difference between merely hot and completely unlivable. In Freetown’s dry season — October through March or April — temperatures can regularly rise above 100 degrees Fahrenheit. But in the lives of Freetown residents, hot weather competes for attention with a host of other needs: food, shelter, clean water, sewers. That, experts say, is why a public servant singularly devoted to heat can channel resources to a problem that is both insidious and silent.

“What’s happening here is becoming unbearable, but it’s also invisible,” Kargbo says. “We have to convince people to make this a priority before it’s too late.”


To understand why extreme heat is so dangerous in a city like Freetown, you have to travel to one of its informal settlements. These crowded shack communities — huddled on hillsides or balanced on strips of exposed coastline — take up a third of the city and are home to about three-fifths of its residents.

In Portee, a shack settlement that runs along a spine of coastline in the eastern part of Freetown, most of the area’s trees have been leveled to create more housing. The effect, in the dry season, is a relentless heat that seems to pulse both down from the sky and up from the concrete. Residents complain of heat rash and children coming home with singed feet from playing on the concrete. Families ration water from communal wells to throw across the dirt floors of their homes, or dip blankets in, to cool them down.

Kadiatu Kargbo (no relation to Eugenia) says the heat also poses a security risk. Because her small tin-roofed shack is so hot and she has no electricity to run a fan, she rarely sleeps inside. But outdoors, she’s exposed to criminals who roam the dark streets nearby. Even if she is inside, the windows and doors are flung open, leaving her family vulnerable.

“Sometimes thieves are coming around our house because they know we can’t close our windows,” she says.

Similar complaints are common in Freetown, but the trend hadn’t been well-studied. “We lacked the evidence to understand the scale of the problem,” Eugenia Kargbo says.

Kargbo says rising temperatures turn up the volume on many of the more obvious problems residents face. Heat saps the limited water resources needed for sanitation, as well as an already-creaking public health care system. Poverty propels people to cut down the very trees that would help make their neighborhoods cooler and more livable, to sell as charcoal or to make space to build more shacks.

And because Sierra Leone has contributed little to global emissions, its residents sometimes resist the idea that they need to change their behavior. “There was an old lady in a slum who said to me, ‘We are not the ones causing the pollution in the sky. You should go to the U.S. and China and tell them to change, not us,’” says Freetown climate activist Hawa Yokie, who works on tree-planting initiatives in the city. “It’s hard for us to explain that, yes, it’s people in those countries who are creating those effects, but we are still the ones who have to live with them.”

That is a paradox at the heart of much heat mitigation work, in Freetown and elsewhere.

“Most people who have the power to change how much humans are contributing to the climate crisis are not the people suffering from extreme heat,” says Jennie Stephens, a professor of sustainability science and policy at Northeastern University. Jobs like Kargbo’s, she says, could help draw resources to the problem before it’s too late.

“Having a temperature where your body can function is something we need to consider as a human right, like having access to food or water,” Stephens says.

Public policy experts also argue that extreme heat inhibits economic development. “Heat is a very insidious form of inequality,” says Amir Jina, an environmental and development economist at the University of Chicago and a founding member of the Climate Impact Lab, which tracks the socioeconomic effects of climate change globally. The group estimates that rising temperatures will cost African countries as much as 7 percent of their gross domestic product over the next 20 years, as high temperatures drive down productivity and increase deaths.

In Portee, though, heat is often seen as less acute than some of the settlement’s other problems. Open sewers, running between the tin-roofed shacks, are clogged with garbage and belch putrid black water onto nearby beaches. Pigs and children play in the runoff, and a rancid smell hangs over the houses. Floods, mudslides, and fires are common. People struggle to afford health care, to send their children to school.

And across Freetown, many residents’ lives are still shaped by the memories of Sierra Leone’s brutal civil war of 1991 to 2002, then the country’s 2014 Ebola epidemic. As a child during the civil war, Kargbo sometimes hid under her bed in Freetown for days at a time, eating her meals in the dark cocoon between her floor and mattress as she waited for the sounds of bombs and bullets outside her window to fall silent. “When I went back to school, some of my friends weren’t there,” she says.


Kargbo grew up to become a banker, but she has spent the last several years working in the administration of Freetown mayor Yvonne Aki-Sawyerr, a noted climate activist. Before becoming the city’s chief heat officer, she headed up the city’s sanitation department.

“I’ve always been a problem-solver,” she says. Now, with help from the U.S. National Oceanic and Atmospheric Administration (NOAA), she’s creating Freetown’s first “heat map,” which will measure air and surface temperatures across the city. Recently, her office completed the first part of the project, surveying 1,000 households to find out how they were coping with extreme heat. Soon, with technical assistance from NOAA, they plan to complete the map itself.

Kargbo’s work also involves finding ways to blunt the most immediate effects of extreme heat. When she and others noticed that the women who sold the city’s staple goods in open-air markets were spending many hours in furious, uncovered sunlight, they devised cloth coverings, designed to repel water and block heat, that could be strung over their vendor stalls.

Kargbo is also working on the Freetown The Tree Town project, which aims to plant 1 million trees by the end of this year, and on setting up a task force on heat health.

A year into the CHO experiment, the results have not been dramatic, in Freetown or in many other cities — though that is perhaps exactly the point. Heat kills in ways that are often anticlimactic, and the solutions can be anticlimactic, too. Athens’ heat officer has developed guidelines for heat management that she hopes to distribute to other Greek cities. Miami-Dade’s CHO launched a public awareness campaign on how people can protect themselves from heat and developed a three-year plan to reduce deaths and illnesses from extreme heat.

McLeod also hopes that having government officials dedicated to heat means that there are always eyes on the problem, even when the world’s focus turns elsewhere. In February, for instance, the U.N. released a detailed report on the effects of climate change. But the same week, Russia invaded Ukraine, and the report sank into the background. Kargbo says her work is to keep climate change on the agenda, however many other things are tugging the world’s attention away.

“People are experiencing climate change, and I’m in a position of power now to do something about how they experience it,” she says. “That wakes me up every single day.”

Hassan Bangura contributed reporting in Freetown.

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Ryan Lenora Brown is a writer based in Johannesburg, South Africa. She has been published in the Washington Post, the New York Times MagazineRunner's WorldThe Christian Science Monitor, and others.

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