Two of the biggest weather impacts in Southeastern cities like Charleston are flooding and heat.
“In the jargon of the resilience world: Floods have more impact. Heat kills more people,” said City of Charleston Chief Resilience Officer Dale Morris.
Extreme heat, which is a sustained 105-degree heat index, causes more weather-related deaths in the United States than any other hazard, according to the National Weather Service. But not everyone’s risks are the same.
Morris calls himself “more of a water expert” who deals with flood risk mitigation. But lately, he’s focused on heat mitigation thanks to the city’s partnership with academic and governmental stakeholders who are researching heat-related health solutions.
“One of the cultural challenges that you find in the Southeast is, ‘Well, it’s hot. What’s new about that?’” Morris said. “In fact, overall temperatures are up [worldwide],” he said. “So yes, it’s actually hotter. There’s a belief that there are tipping points for the beginning of health impacts, even for people who are acclimated to heat.”
There’s an income-related aspect to heat vulnerability, such as air conditioning affordability, said Morris. Lower-income populations may have the same exposure to heat as people with higher incomes, but the heat impact may be greater without equal access to air conditioning.
There’s also occupational implications related to heat for those who work outdoors frequently. It’s not about being exposed to two or three hours of heat in a day — the health impacts from heat come from exposure over long periods of time without any relief.
It takes a village
The City of Charleston is part of the North American Climate Resilience Program, a subprogram of the global Resilient Cities Network. The network includes Boston, Chicago, New Orleans and Houston.
A Medical University of South Carolina (MUSC) research group, Health Outcomes from Temperature (HOT), is investigating the health consequences of heat in Charleston and throughout South Carolina.
Morris believes the HOT studies will provide a greater understanding of urban landform microclimates where the area’s tree canopy and home density affect whether wind or shade can reach those homes.
To him, the heat-health research at MUSC will bolster Charleston’s partnership with other cities and governmental efforts.
“Many hands make light work,” Morris said. “Within the Resilient Cities Network effort, we can share what we learned with other cities, and we can understand what they’re learning. We’re part of a larger set of processes.
“There’s a great opportunity for us to learn more, and this [HOT studies] information can eventually inform city policy or city investments or city actions,” he said.
Behind the scenes
MUSC’s HOT research team is gathering and analyzing data to determine if the number of deaths increase when the temperature increases and which sections of the city are more vulnerable to heat than others, said Dr. Jerry Reves, dean emeritus of MUSC’s College of Medicine. Ideally, the data gathering will be completed this summer.
The research group is led by principal investigator Dr. John Pearce, assistant professor of environmental health and leader of the MUSC Air Quality Lab. MUSC’s HOT team is part of a research consortium that includes The Citadel, the City of Charleston, National Oceanic and Atmospheric Administration (NOAA) and New York-based Climate Adaptation Partners.
One of HOT’s efforts is a retrospective study that will measure the effect of temperature on death incidence by analyzing mortality data from 1999-2021 from S.C. Revenue and Fiscal Affairs Office (SCRF) and statewide meteorological data, according to a HOT study plan written by Pearce and Reves. The goal is to predict which heat events are particularly dangerous for Charleston and S.C., Reves said.
Another HOT effort is a prospective study that will identify two populated areas on the Charleston peninsula that historically experienced different levels of heat during the same high temperature, Reves said.
“One will be an area where heat is not as intense and the other where it is more intense due to such things as minimal tree canopy, crowded housing, poor building materials and inconsistent air-conditioning.”
The City’s Geographic Information System (GIS) Department mapped historically hot and cool spots in the city to contribute to the study. A map of tree canopy coverage within city limits can also be viewed on the city’s website.
HOT will compare temperature and air quality with morbidity and mortality in Charleston based on clinical data gathered from MUSC, Roper Hospital, regional EMS, the weather department and the consortium’s own temperature sensors.
The research team will analyze two areas that are tied to heat-related medical problems to uncover differential factors and eventually improve the area that suffers most.
“For example, if tree canopy is a factor in heat mitigation, more trees can be planted,” Reves said.
Ultimately, the study will compare health outcomes in the vulnerable area after performing heat mitigation to determine which measure protects the most people.
“If health improves with mitigation strategies, then city-wide mitigation will be employed where the benefit is the greatest,” he said. “Global warming is forcing us to be better prepared for heat. And what has been under appreciated is the fact that heat is life threatening.”
The Citadel volunteered to participate in three heat-related projects last year under Dr. Scott Curtis, director of the Near Center for Climate Studies at The Citadel.
The projects gathered heat data across the city to learn where, when and why it was hot. The studies focused on microclimates in areas such as the city’s medical district, to identify characteristics like tree canopy, urban design and heat index.
Curtis is currently looking to participate in HOT’s efforts in 2022 and beyond.