In Charlotte, the burning of fossil fuels has raised summer overnight temperatures by nearly two degrees on average, according to research group Climate Central.
Ashley Ward, director of Duke University’s Heat Policy Innovation Hub, says warmer nights can pose real dangers to residents who don’t have access to or can’t afford air conditioning.
“You can’t rely on being able to open up your windows and take advantage of the breeze to cool down your body and your house,” Ward said.
Lauren Siewny, medical director of Duke University’s emergency department, says hot days followed by warm nights can chip away at the body’s ability to self-regulate.
“In medicine, we talk about it’s like you’re a marathon runner and you’re running multiple races, multiple days in a row without letting time for recovery in between,” Siewny said.
Those extra degrees increase the risk of heat-related illnesses, like heat exhaustion and heat stroke.
‘This is not normal’: Climate change is causing overnight lows to creep higher.
It’s fair to say North Carolina has long been hot and humid in the summer, even before global greenhouse gas emissions raised the planet’s average temperature. But even without melting glaciers, there are clear signs that the region’s climate is growing warmer.
“This is not normal,” said Robert Tighe, a pulmonologist and associate professor of medicine at Duke University, “Meaning that there’s a tendency to think it’s always been hot in North Carolina. The summer is always full of temperature and humidity.”
Tighe said that several days with temperatures over 100 degrees in the spring, summer and fall constitute a big change for the state.
Another big change is rising overnight temperatures, which North Carolina assistant state climatologist Corey Davis called a “canary in the coal mine” for climate change. Scientists started seeing this trend about two decades ago during the winter months. Now, it’s nearly a year-round phenomenon
“Historically, it was very unusual to not see those overnight lows dropping below 75 degrees,” Davis said. “This is a trend that we have seen more and more in recent years.”
That difference is compounded by other environmental factors, such as the urban heat island effect. Building materials like concrete retain heat during the day, storing it up like a battery. At night, they release that heat back into the air, keeping temperatures elevated.
Siewny said the prolonged heat doesn’t just threaten outdoor workers.
“While athletes and outdoor workers are certainly at risk, many of the patients we see in the emergency department are just people simply going about their daily lives,” said Siewny.
She said this is especially true for vulnerable populations, such as older adults, young children, pregnant individuals and people with chronic illnesses, like heart disease, lung disease, kidney disease and diabetes. The danger can also follow folks indoors, especially in homes without air conditioning.
“Heat doesn't cause just heat stroke; it really stresses nearly every organ in our body, and so this worsens existing medical conditions, which can push just about anybody over the edge,” Siewny said.
Solving for heat in a warming world
The prolonged heat from this early summer heatwave is forcing many to make difficult choices about when or if they run their air conditioning.
For people who own a window unit, Ashley Ward, director of Duke University’s Heat Policy Innovation Hub, says the placement of the air conditioning matters as well:
“Prioritize cooling your bedroom, because that’s going to be a smaller area to cool, less expensive to cool. You can shut it off. But also, that allows your body to have that important recovery time overnight,” Ward said.
She says getting relief overnight can reduce the health risks associated with consecutive days of hot temperatures. During the day, Charlotte city residents can seek out cooling shelters to give their bodies a break.
Charlotte’s buses can provide free rides to cooling centers during heat emergencies like this week’s heat wave:
- David B. Waymer Recreation Center, 14008 Holbrooks Road, Huntersville.
- How do I get there? Take bus Route 48X.
- Eastway Regional Recreation Center, 3150 Eastway Park Drive, Charlotte.
- How do I get there? Take bus Route 39.
- Ivory/Baker Recreation Center, 1920 Stroud Park Court, Charlotte.
- How do I get there? Take bus Routes 21 or 26.
- Northern Regional Recreation Center, 18121 Old Statesville Road, Cornelius.
- How do I get there? This area is not served by a bus route at this time.
- Revolution Park Sports Academy, 1225 Remount Road, Charlotte.
- How do I get there? Take bus Routes 2 or 10.
- Tyvola Senior Center, 2225 Tyvola Road, Charlotte.
- How do I get there? Better to drive. Most public transit routes involve 10 or more minutes of walking.
Mecklenburg County public libraries are also air-conditioned and open during normal business hours. Visit the county’s website for additional heat resources.
