Partnership JournalismJuly 9, 2020

Warming Brings Muggier Weather to Jacksonville, Threatening Most Vulnerable

By Ayurella Horn-Muller, Climate Central, and Brendan Rivers, WJCT

An airman assigned to the 557th Expeditionary RED HORSE drinks water while working on a construction site.

Hear this story airing on 89.9 FM WJCT.

Diallo-Sekou Seabrooks was working a job as a concrete finisher last summer when he started feeling dizzy and lay down in the bed of a truck before heading home. The next day, the same thing happened.

In the muggy conditions that August afternoon, “it felt like 100 to me,” said the 48-year old, who was still recovering from kidney surgery at the time. Weather records show it only reached 92, with high humidity giving that heat its extra punch.

Without talking to a doctor, Seabrooks resolved not to put himself in that situation again.

“That was it,” he said. After working outdoors most of his life, Seabrooks left the construction industry. “I’m done.”

Diallo-Sekou Seabrooks

Seabrooks isn’t alone — as muggy weather has descended upon Jacksonville, residents have been retreating indoors for refuge and avoiding exerting themselves outside. Even before the summer, Jacksonville’s average temperature between Jan. 1 and April 30 was 65.1 degrees, the city’s warmest start to the year since 1971, putting outdoor workers and other vulnerable groups at risk of heat stroke.

Some of those most at risk include the elderly, people with schizophrenia and other diseases that make it difficult to regulate body temperature, and those living in formerly ‘redlined’ neighborhoods — a 1930’s segregationist practice by the federal government of rating neighborhoods, which research has linked to ongoing inequities, including more intense heat.

The Climate Change Threat

This particularly muggy summer fits with a broader trend — the combination of high levels of heat and humidity, which can be deadly, is getting worse in Florida and beyond.


'Humid heat' is another name given to an index for measuring heat that’s important for human health — the wet bulb temperature. Like the heat index, wet bulb temperature measures how heat, moisture and other elements affect the body. If humidity levels get too high when temperature is also extreme, sweating becomes physiologically impossible, which can lead to deadly heat stroke.

Scientists at Columbia University, Loughborough University and NASA published a paper in May revealing the rapid pace with which extreme wet bulb temperatures have been worsening globally, concluding it won’t be long before humans can no longer survive in some parts of the Middle East and South Asia.

In Florida, the frequency with which the muggiest days occurred each year was found to have increased by 75% over a 20-year period, adding to health risks in an already-muggy state.

NASA postdoctoral researcher Colin Raymond — one of two authors of the study, published in the journal ScienceAdvances — said one of the most surprising findings was the severity with which the combination of heat and humidity impacts coastal regions like Florida.

“It was always sort of assumed on some level that the lower temperatures along the coast and the higher humidity was sort of offset when it came to heat stress,” said Raymond. “But just looking at the most extreme events in the last 40 years, there are certain coastline areas [like much of Florida] where that is not the case.”

Cranking Up the Heat in the Sunshine State

For the ScienceAdvances study, the scientists used earth modeling to examine humid heat data from 1979 to 2017 around the world. Then, working with Climate Central analysts, the team calculated state-by-state changes in the Lower 48, analyzing the frequency of the most extreme wet bulb temperature days by U.S. location. They discovered humid heat in Florida — on the hottest and most humid day of every year — has become substantially more intense.

A professor of meteorology at Florida State University, Vasu Misra has been studying humid heat along Florida’s coast. He said the findings are in line with other research, and work is under way to project future conditions as intensifying heat and humidity collide.

“It may come as somewhat of a surprise to some of us that in a coastal region like Florida, heat stress could still be a threat, because people think of sea breezes,” Misra said. “But the humidity is so high that the body is unable to cool down.”

A year after his brush with extreme heat, Seabrooks is working in real estate. But he also describes himself as an urban farmer, which means he still exerts himself outside. When he does, he said, he’s working for himself and on his own terms.

An atmospheric and marine scientist at the University of Miami, Amy Clement suspects what people are experiencing may be even more extreme than what Raymond’s study is suggesting, because of potential problems with weather station data across urban areas.

“This entire year in South Florida has been record-breaking in incredible ways, by a large margin. And that includes heat and humidity,” Clement said, pointing to the effects of climate change caused by pollution from fossil fuels and other industrial activities.

“The issue of heat in Florida has been dismissed by experts for a long time,” Clement said. “I think it's because they think that we're adapted to high heat. But two things — one, the study is arguing that there are limits to that adaptability, and two, we're adapted to high heat because of air conditioning.”

The Injustice of Climate Change

Air conditioning isn’t an affordable cost for many. With a poverty rate of 16%, tens of thousands of Jacksonville residents struggle to pay the bills. In recent years, homeless shelters like Sulzbacher have opened cooling stations to help desperate residents escape the heat.

Now COVID-19 precautions and regulations have forced shelters and businesses to modify the ways in which they operate. Chief Development Officer Eileen Briggs said Sulzbacher opened a second cooling center to help ensure social distancing and is screening residents' health before they can enter.

“It’s had a huge impact,” Briggs said. “We work with a population that congregate — they have to stand in line for meals, they live in group living situations where they don’t have a private space of their own.”

Experts say the pandemic underscores the importance of ensuring more equitable access to air conditioning, street trees, public transportation, and food — the types of things for which Jacksonville local and architectural designer Ashantae Green has pushed.

Green spends much of her time advocating for community-based solutions to hunger and food insecurity, and is running for a supervisor seat on Duval's soil and water district.

Ashantae Green in a community garden she manages.

As WJCT News partner The Florida Times-Union reported in February, summertime temperatures in Jacksonville neighborhoods that were discriminated against under redlining policies roughly a century ago are nearly 10 degrees hotter than in tree-heavy, historic neighborhoods like Avondale, Ortega Terrace, Venetia, San Marco and Granada.

Based on race and ethnicity, banks declined to provide mortgages and other financing tools in redlined neighborhoods, meaning little could be spent maintaining or improving those areas. Green grew up in a redlined area on Jacksonville’s Eastside and says people’s having heat strokes, fainting, and getting dehydrated were all so commonplace that she didn’t recognize the connections to climate change and racial disparities until recently.

“Although redlining was outlawed many, many years ago, the effects are still prevalent,” Green said. “Especially when we’re talking about climate issues and increased heat.”

This story was produced through a partnership between Climate Central and WJCT News, from NPR member station WJCT in Jacksonville, Florida.

Read the original story at WJCT here, or listen to the radio broadcast here.

Brendan Rivers can be reached at, 904-358-6396 or on Twitter at @BrendanRivers.