The city of Jacksonville and the University of North Florida are partnering on a heat mapping study that officials hope will reveal which parts of town are most threatened by extreme heat, which scientists say is being exacerbated by climate change.
Conversations about climate change in Florida tend to focus on things like hurricanes, flooding and sea level rise, but extreme heat is actually the deadliest form of hazardous weather, according to the National Weather Service. Between 1999 and 2010, extreme heat was linked to 7,415 deaths in the U.S., an average of more than 600 per year.
“I think often we focus on flooding because it's the most financially damaging threat that we have. It can really impact property and have a high price tag, but ultimately urban heat is the deadliest natural hazard that we face,” said Jacksonville Chief Resilience Officer Anne Coglianese, who has been tasked with preparing the city for the effects of climate change. “It [extreme heat] takes more lives every year than hurricanes, wildfires or tornadoes. So it's really kind of a slow-moving hazard but one that I'm very focused on.”
Climate change is pushing temperatures up across the country, including in Jacksonville, where the average summertime temperature has already risen by more than 1 degree Fahrenheit since 1970. Summer night temperatures have increased by about 1.6 degrees Fahrenheit in the River City during that time. By 2050 Jacksonville is expected to see as many as 80 days a year where heat index values (what temperature it feels like) exceed 100 degrees.
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Hotter summer temperatures can cause potentially deadly health issues, like heat stroke. This is even more prevalent in vulnerable and historically marginalized populations, like seniors, young children, those living in formerly redlined neighborhoods and low-income people who can’t afford air conditioning.
In homes without air conditioning, warmer nights mean people will have more trouble cooling off and recovering after intense heat events. One study finds that warmer nights can also make it harder to get a good night’s sleep. Summer heat can also contribute to poor air quality by trapping pollutants close to the surface, which can make respiratory issues worse for people with asthma and other lung diseases.
Urban areas like downtown Jacksonville tend to be hotter than nearby suburban and rural areas due to what’s known as the urban heat island effect, which is caused by a lack of trees and green space and a higher prevalence of heat-absorbing surfaces and materials like roads and buildings.
Studies have found that this urban heat island effect disproportionately affects minority and low-income communities, which tend to have less shade-covering trees than whiter, wealthier neighborhoods. As WJCT News partner The Florida Times-Union reported in 2020, summertime temperatures in Jacksonville neighborhoods that were discriminated against under redlining policies are nearly 10 degrees hotter than in tree-heavy, historic neighborhoods like Avondale, Ortega Terrace, Venetia, San Marco and Granada.
The city of Jacksonville and UNF plan to gather data for the heat mapping project during the hottest week of summer 2022.
“There's sensors that will be attached to cars, and they will run predesigned routes throughout the city multiple times a day, every day for a week. And then at the end of that week, we're able to aggregate that data and get a base layer in GIS that shows where air temperatures are hottest throughout the city,” Coglianese explained.
Coglianese says this heat mapping study, along with an ongoing vulnerability study looking at flooding and sea level rise, will help officials figure out what needs to be done to protect the city from the many impacts of climate change and where those efforts need to be implemented first.
Funding for the project comes from the National Integrated Heat Health Information System in partnership with Climate Adaptation Planning and Analytics Strategies.
