Columbia: Infamously Hot?

An exploration of climate change and local heat-mapping strategies

by Aaron Falls / Garnet & Black

The city of Columbia is no stranger to heat. Nestled between the Atlantic Coastal Plain and the lower stretches of the Piedmont region, the area is notorious for its hot and humid summers, so much so that the city’s visitor bureau christened the town as “Famously Hot Columbia” in 2008 as a slogan to garner tourism. While this name has historically been a conversation point which sparks laughter and solidarity, there is serious change happening in South Carolina's capital. As climate change accelerates and the planet warms, Famously Hot Columbia is getting hotter. The concerns surrounding these temperature spikes are no laughing matter.

Columbia, and South Carolina as a whole, are located within a humid subtropical climate zone characterized by hot and humid summers and mild winters. However, the city of Columbia is uniquely affected by this climate due to its geography. The Free Times reports that due to its distance from the coast, the city lacks the ability to effectively moderate heat. To compound this further, Columbia’s more urban areas, which have plenty of asphalt or concrete and little shade, absorb and store heat in a process known as the heat island effect. All of these factors combine to create our uniquely blistering air. With record-breaking summers happening in succession, certain institutions like the city government and the University of South Carolina have begun to take action.

Last August, a variety of stakeholders converged to investigate and map heat in the city of Columbia. Led by Dr. Kirstin Dow, a geographer and professor at the University of South Carolina who facilitated a similar process in Charleston, the project involved volunteers from the university as well as support from the Columbia Tree and Appearance Commission (CTAC), the National Oceanic and Atmospheric Administration (NOAA) and Climate Adaptation Planning and Analytics (CAPA) Strategies. The project’s goal was to identify heat disparities within the city to inform counter-measure policies, essentially, to identify which areas were hotter than others. Through a variety of strategies, the project was completed, and a report was published summarizing the findings for use in policy decisions.

Dr. Dow said that she is, “looking to create climate science that’s decision relevant,” with her specialty being, “human-environment interactions around climate change.” She believes that it is crucial to utilize heat mapping and to recognize heat as both an environmental and socioeconomic factor. Emphasizing the urgency of this work, she said, “it’s documented that we’re seeing more hot days than we have in the past decades. It’s not soon, it’s past. It’s here.” While Columbia’s response was recent, she has already seen success through her work in Charleston. When the Medical University of South Carolina approached Dow saying that they wanted to calculate flood risk, she and her colleagues proposed they examine heat impacts as well, leading to a full-fledged study. “There have been a number of successes,” Dow said. “Heat is now in Charleston’s comprehensive planning as a consideration. The Charleston Resilience Office, when they think about their problems, they’re talking about water and heat.” Riding this victory in Charleston, Dow wrote a proposal to NOAA, CAPA Strategies and the Richland County Conservation District to mimic the Charleston research in Columbia. In the past five years or so, NOAA has been utilizing CAPA Strategies technology to conduct heat mapping in a cohort of American cities about 40 to 50 strong. Through Dr. Dow’s proposal, Columbia joined the cohort, and the study was approved.

The study was performed over two days (Aug. 6-7, 2022) utilizing a variety of sensors provided by CAPA Strategies and the university. The main form of data collection involved volunteers using mobile heat sensors as they drove around the city. The routes were determined by Dow and her team, who analyzed satellite imagery to determine routes that would incorporate a wide array of comparative land types (wooded, open field, urban, water features, etc.). Dow remembers it fondly, saying volunteers, “came over, they picked up the sensors which are sort of mounted on some PVC pipe and you stick it out your window, kind of like a game day flag, and drive around slowly with them.” These sensors would collect data about every five seconds, serving to capture, “air temperature and humidity at about six feet, about where we experience it personally.” Some volunteers also used Forward Looking InfraRed (FLIR) cameras, which capture surface temperature as opposed to air temperature. “The FLIR cameras tell you how hot the surfaces of things are,” Dow said. “They say ‘don’t let your dog on the asphalt when it’s really hot’, they’re talking about direct contact to surface.” Finally, there were ten stationary sensors utilized for multiple months. Dow relates that this element of the study was somewhat unique to Columbia and has not been widely replicated in other cities.

The results of the study are striking. Dow relates that, “we’ve found that as early as six o’clock in the morning, there’s a nine-degree difference around town depending on where you live,” which translate into, “temperatures as high as eighteen degrees different in the middle of the day.” According to Dow, this significant heat discrepancy is primarily due to the heat island effect, as the areas, “where there’s asphalt and the room for tree canopy is limited are the much hotter areas of the city. The Harbison Mall stands out. Sandhills Mall. The downtown area. Even the quarry, over in Cayce.”  This discrepancy could translate into mass inequality when it comes to heat stress, as neighborhoods without cooling strategies absorb more heat stress into the landscape and into their residents. Dow believes that our responses should include three steps: cooling down, assisting those affected by heat stress and striking at our combined greenhouse gas emissions, the root cause of the heat. And, she’s not alone.

Scott Holder is a Land Development Planner that works for the city of Columbia’s Landscape and Tree Ordinance as well as, “one of two staff liaisons to the Columbia Tree and Appearance Commission (CTAC).” Holder assisted the study through CTAC, “by coordinating City departmental involvement,” and cites Dr. Dow’s presence as essential, saying that, “she spearheaded the entire effort and without her, it wouldn’t have been possible.” Holder’s concerns when it comes to the study’s results are not directed at the heat itself but at our diminishing countermeasures. “We are removing canopy more than we are replacing. It’s no secret that trees provide many benefits like reducing stormwater runoff, oxygen regeneration, wildlife habitat, but possibly most importantly, they reduce cooling costs through evaporative cooling and providing shade,” Holder said. While many participants in continued canopy loss are compensating by planting an equal number of tree saplings as they consume mature trees, “canopy trees take many years to reach their mature size," Holder said, "we need to consider conserving more mature trees in lieu of removal and replanting.” Holder believes that strategies like, “undergrounding utility lines and installing suspending paving systems,” are advantageous for increasing the urban canopy, though these strategies take time in a bureaucratic system like ours. Holder provides some insight, “As the Chinese proverb says, ‘The best time to plant a tree was 20 years ago. The second best time is now.’”

Dow has no shortage of ideas to counter the growing heat either. “We have a lot of options locally to think about how to do this,” Dow said. She believes reducing the urban heat island effect in Columbia is possible, “if you can create more shade, if you can put vertical green walls up on the sides of buildings that cool them down and prevents them from becoming these heat magnets that dissipate heat all day long.” She cites other cities’ urban design plans, saying that there are strategies where buildings are oriented to create a canyon for cool airflow and increased walkability. She also emphasizes that we need to think about strategies other than adding water features, as the humidity of the locale makes adding more moisture into the air a relatively obsolete practice. "We know," Dow said, "on a humid day here, it's much much worse." When cooling strategies aren’t enough, however, she emphasizes the importance of looking after those affected by heat stress. “Diabetes, respiratory conditions, cardiac conditions, obesity. Many of these things are stresses. And, it’s not just during heat waves. This weather can be hot enough in the summer that it’s a serious stress on people’s bodies,” Dow said. She makes sure to emphasize the socioeconomic significance of this response pattern as well. “We have a large number of people who live in rental properties here. 50 percent of the population of Columbia is in rentals,” Dow said. This is important because renters, “don’t have opportunities to make modifications to their home, to make them more energy efficient. And, for low-income people, many of whom are renters, energy poverty is a real issue. The amount that you spend on your heating bill can be a substantial portion of a limited paycheck.” 

Ultimately, due to climate change’s gradual progress, albeit at a somewhat alarming pace, the city is getting warmer. But, all is not lost. Dow relates that, “we still have choices to make on how much change we’re going to experience.” She emphasizes the importance of engagement on a local government level, saying, “we don’t have a heat mitigation plan. We don’t have a cooling center plan. Those are things we could think about going forward.” Holder echoes her concerns. “If we keep losing more canopy than we replace, our summers will become even more unbearable to walk,” Holder said. In terms of what ordinary people should do heading forward, Holder encourages people to, “get involved and make your voices heard.” Dow recommends that people look after themselves as these spikes are increasing, emphasizing the importance of, “finding places to be cool in the famously hot city”. 

Click the link below if you’re interested in looking through the heat-mapping study’s summary report!