Winter may be approaching, but everybody knows South Carolina can get really hot in the summer. Climate change is only making the problem worse. This summer, 14 American cities, including Columbia, used grant funding from the National Oceanic and Atmospheric Administration (NOAA) to map the hottest spots, called urban heat islands, in each city, with the goal of using the information to mitigate the increasing heat, and offer people some relief.
Bob Petrulis is chair of the Climate Potection Action Committee, which provides citizen advice to city council. “The heat mapping is really to get an idea of where the hot spots are in town. There are some places in town that are hotter than others,” he said. “What we want to do is be able to identify those places and kinda create some kind of proactive response. And that might be bringing the city arborist to talk about tree cover. It could have to do with opening public schools in the summer to provide some cooling shelter for local people, things like that.”
In discussing the causes and dangers of heat islands, University of South Carolina geography Professor Kirstin Dow said the hottest parts of the city can be as much as 20 degrees higher than other parts. “And that’s caused by having more buildings and asphalt that accumulate heat through the course of the day.
“And more cars and outdoor air conditioning units and big pieces of equipment and trucks and so on” that eliminate waste heat, Dow said. “And you just end up with a hotter environment in urban areas. Lots of people, lots of traffic, lots of buildings. And the concern is, heat’s dangerous.”
Sixteen teams measured the temperatures in pre-determined spots around the capital city in August, as other teams did last year in Charleston. Petrulis outlined how the survey was conducted. “Basically, you’ve got a sensor that goes on your car. It’s like one of those team flags that you put on your window,” he explained. “It contains a temperture sensor and also an air speed sensor.
“then that’s all connected to a GIS system, so the data that’s being collected, they know exactly where it’s being collected from.
“We went out first thing in the morning, about 6:00 as the sun was coming up. And then during the day, we’d go back at 3:00 and do another run on these carefully laid out routes. You know, that’s the hottest time of the day. And then the evening run at 7 at night, to see what it’s like early in the evening.”
The results of the survey were released a few days ago. Dow said addressing the heat islands depends on the causes of the heat and where an island is located.
“So if it’s about lots of asphalt, then there are ways to make the asphalt, the roads, more reflective so they don’t absorb as much heat,” she said. “You can also plant more trees and shade it. And in places where we don’t have shade, there are interesting, beautiful strategies called green walls, where you can use a cable system or trellis system to cover the outside walls of buildings with vines or something that actually cool the building.”
Dow added that an effective way to cool an area is also a natural one: plant lots of trees.
“Trees do an amazing job of cooling areas,” said the professor. “I was involved in the work down in Charleston, and the part of the city that’s done best in retaining its canopy is about 12 degrees cooler than other parts of the city.”
Trees also are good at capturing floodwaters, said Dow, who encourages people to plant trees in their own yards. “Trees are good! Trees are energy savers. They’re one of the ways you can address the problem with the heat.”
Smaller South Carolina cities also have heat islands, Dow said, including Aiken, Florence, Rock Hill and Sumter. She stressed the importance of taking action now, because climate change is not going to cool down in the future.
“The historic record shows that Columbia’s already gotten more days over 90 degrees. We’ve gotten 10 more since the 1980s. And we expect to get another 25 by mid-century,” she warned. It’s a really good idea to start preparing now. Put the trees in, put the surfaces in, don’t build in an investment that’s going to make what’s going to be hot, even hotter.”
Petrulis added that rising temperatures are a large scale challenge, and that being proactive now will make our cities more livable while addressing the climate issues that we know are developing.
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