Climate change and urban landscapes are colliding to amplify heat and cooling demand.
This report can also be found on Climate Central.
Patricia Murray sat in her home office toward the end of a weeklong heat wave, the third for the year with temperatures exceeding 90 degrees, describing how she keeps cool without air conditioning even as Durham’s summers get progressively hotter.
“When I know I’m going out in the afternoon, I’ll wring out [a towel] and put it around my neck,” said the spry 68-year-old, who also uses box fans and ceiling fans to push cooling breezes through her home. “I suggest if you don’t have air conditioning, that’s a lifesaver — got to have a ceiling fan.”
As heat-trapping pollution increases temperatures globally, and concrete and hardtop landscapes intensify heat in Durham and other cities, Murray’s strategies provide a snapshot of what it might take to survive for people who live on fixed incomes and can’t afford cooling.
Such urban heat islands occur in cities and describe conditions where asphalt, concrete and other materials used to pave streets, parking lots and sidewalks and to erect buildings contribute to hotter temperatures by absorbing the sun’s heat before releasing it into the atmosphere.
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Temperatures on Murray’s block can be 6 to 7 degrees warmer than those in a rural setting with less development, Climate Central modeling shows. Other parts of the city are even hotter. About 1,700 Durham residents live in areas with temperatures elevated by at least 9 degrees. In Charlotte, which is home to more than 900,000 people, an estimated 6,000 people live with those extreme levels of urban heat.
These heat islands are a particular problem for people of color, according to a study published in Nature. The researchers found that, on average, people of color live in census tracts with higher summer “daytime surface urban heat island intensity” than white people.
That was the case in 96 percent of the 175 largest urbanized areas in the continental U.S.
Those same authors found that people living in poverty have the highest chance of living in these intensely hot areas.
“Before I had gotten on Social Security, I went through some pretty hard financial times,” Murray said. “I’ve had my water and electricity cut off, and I’ve had to rely on solar lights.”
Murray arrived in Durham more than 20 years ago to care for her aunt, whose health was failing. Her current home once had air conditioning, but when the system broke, Murray decided not to have it repaired.
Since then, average summer temperatures in Durham have risen 1 degree on average, analysis of weather station data shows. This rise is part of a longer-term warming trend caused by atmospheric pollution that’s driving up the costs of cooling homes and other buildings. Since 1970, estimated demand for air conditioning in Durham has increased more than 40 percent, analysis of weather data shows.
On a Thursday in late August when North Carolina Health News visited Murray in her home, Durham’s temperature topped out at nearly 95 degrees, which was nine degrees warmer than the historical average. Climate Central’s Climate Shift Index shows the uncomfortable average temperature on that day has become at least four times more likely because of climate change.
“We know our summers are hot, and they’ve always been hot,” said Kathie Dello, state climatologist and director of the North Carolina State Climate Office. “But this isn’t our parents’ heat. […] It’s a new kind of heat, and it’s relentless.”
Extreme heat describes temperatures that exceed historic averages for a given area. Rising temperatures are also worsening humidity in places like Durham, exacerbating health risks.
Annually, more than 1,200 Americans die from extreme heat, according to a report by the Centers for Disease Control and Prevention. Globally, between 2000 and 2019, approximately 489,000 people died yearly from heat-related causes, according to data provided by the World Health Organization.
Dello said there was a time when North Carolinians could get a break from the heat of the day after the sun went down, but even that is changing. In the 1970s, on average, the Raleigh-Durham area had only one occasion per year where the days and nights were both too hot. But data from Climate Central shows that the weather now stays hot all day and all night for an average of eight days each year.
Dello said it’s really apparent in the nighttime temperatures.
“So much of our Southern living is kind of based around, ‘Okay, well, it’s a really hot day, but it’s going to cool down overnight. We’ll turn on the fans and open up the windows.’ That’s just not happening anymore.”
Not being able to cool down after a long hot day can lead to potentially fatal heat-related illnesses such as heat exhaustion or heat stroke. Exposure to extreme heat may also contribute to other adverse health conditions, including heart attacks and strokes. Older adults, young children, the mentally ill and people with chronic diseases are among those most affected by extreme heat, according to the CDC.
Ground Zero
Murray’s modest one-story home is roughly two miles southeast of Hayti, Durham’s historic Black community.
More than five decades have passed since the urban renewal movement swept across the country, displacing businesses and homes in primarily Black communities. Established by the 1949 Housing Act, the goal of the program was to provide standardized housing in low-income Black neighborhoods nationwide.
However, from the 1950s to the 1970s, homes and significant community landmarks, including churches and businesses, were destroyed or relocated to make room for highway projects.
Such was the case in Durham’s Hayti community.
In the 1970s, the Durham Freeway/Highway 147 was built to connect downtown Durham to the Research Triangle Park. The freeway tore through Hayti, replacing houses and community landmarks with miles of concrete and asphalt and limited green spaces with shade.
Hayti is now considered an urban heat island because of its dearth of trees, which are necessary for mitigating temperatures. It also has an abundance of asphalt and concrete surfaces, which absorb heat during the day and release it at night. This process prevents certain parts of the city from cooling down after sunset.
The average temperature on a hot day in an urban zone can be 1 to 7 degrees hotter during the day than that in a rural setting. After the sun sets, heat absorbed by sidewalks, concrete and bricks is released through transpiration, increasing nighttime temperatures between 2 and 5 degrees, CDC data states.
Max Cawley, a climate researcher at Durham’s Museum of Life and Science, described what happens when urban communities have more impervious surfaces than they do tree canopy.
“Sometimes people living just blocks apart from one another experience different heat levels depending on the built environment around them,” Cawley said in a radio interview. He added, “Our communities did not assemble themselves, they are based on decisions that people have made in the past.”
Very often in the southeastern United States, those systems have turned out to be exclusionary.
“Because of the way we plan our communities today, some people who live in areas that have lots of impervious, hard, dark surfaces experience more heat and are more in danger and peril,” Cawley said.
He noted that these communities “are more vulnerable to that heat than people who are living in, for example, communities that are planned to have more shade trees, more green space and more infrastructure. [Which] today acts as a kind of service and protects them during very high heat days.”
Angela Lee is executive director of the Hayti Heritage Center, a local cornerstone for arts and culture. She reflected on how the community is still recovering from changes brought on by the freeway.
“When you drive along Fayetteville Street, particularly along the corridor where we are […] This is a street that was created by (Highway) 147 and did not exist before the [highway] came through,” Lee said. “The backside of our building, now called Old Fayetteville Street, was the main street. It was full of trees and shrubs, and it was beautiful. It didn’t have this wide street where people drive too fast, and it’s not safe.”
Phoenix Crossing Shopping Center is a strip mall across the street from the heritage center. The shopping center’s large asphalt parking lot has room for nearly 150 vehicles. The ornamental crape myrtles planted in grassy medians resemble tiny green islands afloat in a black sea. On a particular day in August, when the temperature reached the mid 90s, the trees offered no relief from the heat.
About a 10-minute walk south from the Hayti Heritage Center and Phoenix Crossing Shopping Center sits Lincoln Community Health Center. The one-story medical facility, which has served low-income residents since the 1970s, has a tree-less 2.6-acre asphalt parking lot.
“Everyone knows that, yes, when the Hayti community was dismantled because of the freeway, a lot of structures were destroyed—homes and businesses, and a few thousand folks were displaced,” Lee said. “But what you didn’t hear a lot about [is] the environmental impact.”
She added: “When it’s [hot], and you don’t have nice shaded paths or access to shaded sidewalks or even stops where you can get something cool to drink, you’re not encouraged to be outdoors. You don’t want to move around; your children don’t want to move around. That also leads to health disparities because you’re not active, [or] living active, healthy lives in your communities.”
Easing the impacts
Cawley is participating in a national heat monitoring project with the National Oceanic and Atmospheric Association, and he has conducted heat research on Durham. He points out that living in an urban heat zone can be expensive.
“We know that heat has tremendous and inequitable health impacts, but also hits Americans in their budgets in a disproportionate way,” Cawley said. “People who live in heat islands tend to pay a higher percentage of their wages on cooling their homes. If they’re not able to, then they are more at risk, particularly at nighttime.”
A national analysis by Noah Kittner, an assistant professor in the Gillings School of Global Public Health at UNC Chapel Hill found that 16 percent of U.S. households live in energy poverty: They spend more than 6 percent of their household income on energy bills.
Residents in these heat islands may have to choose between running the heat and air conditioning or paying for other essential expenses.
Aside from ongoing tree planting efforts, Durham is trying to reduce the energy burden that presents a barrier to low-wealth residents who don’t have air conditioning — or can’t afford to run it. Through possible federal grants, the city is exploring ways to equip the homes of low-wealth residents with solar panels that could lower the cost of running an air conditioning unit.
This is an idea that Murray supports.
“I would jump all over that if they [offered solar] for lower-income people,” she said. “I would, because I have the perfect roof for it.”