Last week was hot. Very hot. Heat readings taken with an infrared sensor in NoDa clocked surface temperatures at 140 degrees Thursday afternoon. A heat dome settled over the Southeast, causing near-record-setting temperatures over the Fourth of July weekend.
But how you experienced those high temperatures depended on where you live. For example, the neighborhood NoDa is a known hotspot, and the sidewalk reached over 130 degrees on Thursday. Grassy areas fared much better. In Cordelia Park, the lawn measured 84 degrees, with shaded areas a few degrees cooler.
But the most insidious climate impact is when the sun goes down and overnight low temperatures stay high.
The sun goes down, temperatures stay up
“I'd say those overnight lows have been the canary in the coal mine in terms of climate change in North Carolina,” said Corey Davis, North Carolina’s assistant state climatologist.
This is compounded by the urban heat island effect. Roads, roofs and other hardened surfaces store heat during the day and slowly radiate it at night, raising local temperatures. Wednesday night, surface temperatures on North Brevard Street, which runs parallel to the light rail, stayed warm well past sundown. The following morning, the road still measured 87.1 degrees.
But whether you live near uptown Charlotte or next to Latta Nature Preserve, you’re still feeling the effects of climate change during this heatwave.
“We have seen one to two degrees of warming in our nighttime temperatures, so in some ways that's irrespective of that land use change and development,” Davis said.
When the human body can’t get a break from the heat overnight, stress builds up. That cumulative stress wears down the body, compounding the risk of heat exhaustion and other illnesses.
“Not dropping below 75 degrees sets off alarm bells, because whether you're a plant or a pet or a person, if you're outside overnight, you need some cooler temperatures to help your body rest and recover,” Davis said.
This week, overnight temperatures are hovering around 75 degrees. That means it’s important to know the signs of heat stress: Cramps are a sign that your body is struggling, even if you’re still sweating and your fever remains normal. Other signs include difficulty thinking or moving.
Climate enemy No. 1: the heat
Last year, the Charlotte Office of Sustainability and Resilience ranked the city's climate-related threats.
“Extreme heat was the highest risk. But it was also the one that the public had shared with us was the biggest concern they had,” said Robyn Byers, the assistant director of Charlotte’s sustainability office.
Her department partnered with the Charlotte Heat Mappers to survey around 400 Mecklenburg County residents. More than three-quarters of respondents said heat had a moderate-to-major impact on their lives.
The state Department of Environmental Quality predicts that by the 2060s, Charlotte will experience nearly 40 additional days with a heat index exceeding 95 degrees. And that’s the best-case scenario.
One respondent wrote, “The heat… raises my electric bill due to using air conditioning more frequently. This affects my financial health.”
Another said, “I can’t afford a gym membership and AC is expensive, so working out indoors is also not a great option.”
Respondents also ranked solutions. Expanding Charlotte’s tree canopy in public spaces was the most popular. Others included weatherization programs, adding more public swimming pools and making green spaces more accessible.
Byers said the city is already taking steps to mitigate heat stress in parts of Charlotte.
“We have adopted what we’re calling road sunscreen,” Byers said. “So, blacktop, asphalt is one of those hardscapes that a lot of people can feel the heat coming off of because it absorbs the sunlight.”
So far, the city has treated just over 11 miles with the white pigment titanium oxide, or road sunscreen. But it’ll take more than that to keep Charlotte cool in the future. Braden Drive in west Charlotte had already received treatment, but surface temperatures still exceeded 120 degrees last Thursday. Meanwhile, an unsheltered bus stop for route 13 sat in the sun, its thin shadow falling upon the treated road.
The Office of Sustainability and Resilience is also partnering with Duke University to inventory climate actions and identify the gaps the city still needs to address.
