‘Shade deserts’ a health problem as cities face extreme heat from climate change

TAMPA — If it weren’t for the traffic along South MacDill Avenue in Tampa, Javonne Mansfield swears you could hear the sizzle of a frying pan.

The sun is scorching with such violent intensity that even weathered Floridians can’t help but take note.

In a hard hat, Mansfield pushes a shovel into the earth. Heat radiates from the road, the concrete parking lots. It’s around 10:30 a.m., and his crew is starting a 10-hour shift fixing traffic lights in West Tampa. Cloud coverage is thin and wispy. There’s no greenery or trees to shield them, no refuge from the sun.

“I can feel it,” Mansfield says, “like I’m cooking.”

A mile south, near Palma Ceia Golf and Country Club in South Tampa, Kiki Mercier walks a poodle mix along a row of stately homes. It’s the same city on the same July day, but here the heat feels different.

Plush lawns spotted with children’s toys help absorb the sun’s rays. But it’s the dozens of live oak trees with sprawling branches that make the biggest difference to Mercier, who walks dogs for a living.

Here, it feels possible to be outside, protected by natural tunnels of shade.

As the climate warms, people’s health and quality of life hinge in part on where they live or work. Green space and shade can be the difference between a child playing outside or being stuck inside on hot summer days, between an elderly person fainting while waiting for a bus or boarding safely, between a construction worker suffering heatstroke or going home safe.

Neighborhoods with more trees and green space stay cooler, while those covered in asphalt swelter. Lower-income neighborhoods tend to be hottest, a city of Tampa report found, and have the least tree canopy.

The same is true in cities across the country, with poor and minority neighborhoods disproportionately suffering the consequences of rising temperatures. Research has found the temperatures in a single city, from Portland, Oregon, to Baltimore, can vary by up to 20 degrees.

Summer in the city is hot, but some neighborhoods suffer more

In a leafy suburb, a steamy summer day might feel uncomfortable. But a few neighborhoods over, it might be dangerous.

As Americans brace for an increasing number of hot days and extreme weather linked to climate change, medical professionals say rising heat will make health inequities worse.

“Heat affects quality of life,” said Cheryl Holder, co-founder and interim director of Florida Clinicians for Climate Action, a coalition of medical professionals that advocates for solutions to climate change. “It’s poor and vulnerable patients who are suffering.”

Tampa and other cities are trying to build heat resiliency into their infrastructure — taking steps such as boosting their tree canopy.

Benjamin Brown heads indoors after taking out his recycling in Tampa. His street has very few large, shady trees.

Several large, shady trees create a canopy on West Prospect Road near South Marti Street in Tampa.

Unrelenting heat

As a human body warms, sweat gathers and evaporates, transferring heat into the air. In Florida, though, the humidity makes it harder for that cooling system to work.

“The sweat just doesn’t evaporate, so you don’t lose heat as effectively,” said Dr. Patrick Mularoni, a sports medicine physician at Johns Hopkins All Children’s Hospital in St. Petersburg, Fla.

In unrelenting summer months, doctors like Mularoni have seen the toll heat can take. Muscle cramps and headaches. Fatigue. Heatstroke — which can be fatal.

Daily temperatures are one benchmark of heat’s impact, but factors like humidity, wind speed and sun angle also affect the toll on the body.

The heat index, often called the “feels like” temperature, takes into account temperature plus humidity. The thermometer might read 91 degrees, but the heat index could mean it feels like 110 degrees. The National Weather Service defines any heat index of 105 degrees or higher as dangerous.

Between 1971 and 2000, Tampa saw about four days a year with a heat index above degrees. By 2036, that number is projected to rise to as many as 80 days a year.

Without extreme steps to reduce global temperatures, scientists predict, Tampa residents will experience 127 “dangerous” days annually by 2099 — more than one-third of the year.

When the body temperature goes up to 104 as a result of overheating, the body begins shutting down. Decreased blood flow to organs can cause multisystem organ failure.

Without prompt intervention to lower body temperature, heatstroke can be fatal.

This summer, heat waves have killed at least 13 people in Texas and one in Louisiana, where the heat index reached 115 degrees. In Arizona, at least 18 people have died, and 69 other deaths were being investigated for potential links to heat illness. Other Arizonans have been hospitalized for serious burn injuries after touching scalding concrete.

As far north as Maryland, a 52-year-old man died in July — the state’s first recorded heat-related death of the year.

In Parkland, Florida, a 28-year-old farm worker died of heat exposure in January after hespent hours pulling weeds and propping up pepper plants. Investigators said his death was preventable. He’d recently moved from Mexico, Uit was his first day on the job.

In Tampa, a shrinking canopy

Last year was Tampa’s hottest ever. The city’s average annual temperature has risen by 2.5 degrees since record-keeping began in 1891, according to the city’s Climate Action and Equity Plan.

Meanwhile, a natural tool for reducing heat has slowly been disappearing. According to a 2021 study, tree canopy coverage in Tampa is at its lowest in 26 years.

Experts say vanishing tree cover coupled with hotter summers is a lethal combination.

The uneven distribution of trees — and therefore shade — means lower-income and Hispanic neighborhoods are more affected by heat, Tampa’s city report found.

MacFarlane Park, east of Tampa International Airport, ranks among the city’s least shady areas, according to the report, with 21% canopy coverage — nearly one-third less than the city average.

Only 15% of East Ybor City and 18% of North Hyde Park benefit from tree cover. These neighborhoods have gradually lost trees the past few decades.

Many factors influence the shrinking canopy, including the loss of old and dying trees and the removal of trees for construction. In some lower-income neighborhoods, residents have chosen to cut trees down because they can’t afford the upkeep or because dangling branches pose a threat.

Some wealthier areas are seeing faster and more recent canopy loss as old trees die or are cut down, but their tree cover is still double that of poorer neighborhoods.

On the upper end, the canopy of mansion-lined Bayshore Boulevard isn’t far behind those of a series of housing developments along Flatwoods Park in New Tampa, one which hovers around 73% coverage.

Gray Gables, a neighborhood bordering West Kennedy Boulevard, lost the highest proportion of trees from 2016 to 2021, but canopy still covers 38% of its area.

It’s not just shade the city is losing. Trees release water vapor, which helps cool people. Each year, according to the city’s 2021 canopy study, Tampa’s trees remove 1,000 tons of air pollutants, capture the potential carbon dioxide emissions of 847 tanker trucks’ worth of gasoline and reduce stormwater runoff equal to 850 Olympic swimming pools.

Natural shade also determines the paths people walk — or whether they walk at all — and how often their kids can play outdoors.

On a summer’s day in West Tampa, a girl on a bike pedals, sweat dripping from her brow. A woman pushing a stroller contorts her body while waiting for a bus, trying to make use of a strip of shade no wider than six inches, cast from a traffic pole.

Angela Morris stands in her sun-drenched driveway and rinses sandy beach toys with a hose. She’s layered in sunscreen, but, in the blazing heat, her skin is already burning.

“It’s almost unbearable,” Morris says.

Her kids — ages 2 and 5 — are inside. Do they ever play outside in the summer?

“Never,” Morris says. “It’s a lot of younger families with kids who would benefit from some shade and a sidewalk.”

Angela Morris hoses off her children’s sandy beach toys in her driveway in Tampa. Her newly built home lacks large trees, there’s no shade on her street.

Hard to track impact

Heat-related deaths are difficult to track. A doctor might code a fatal heart attack on an extremely hot day as a cardiovascular event without noting that heat likely worsened the condition.

“What often gets lost are the circumstances surrounding deaths and illness,” said Christopher Uejio, a Florida State University researcher who studies the effects of climate on health and has led projects for cities around the country.

Extreme heat in the United States kills more people than hurricanes, floods and tornadoes put together, according to the National Weather Service. It’s the country’s No. 1 weather-related cause of death.

About 67,500 emergency room visits and just over 9,000 hospitalizations across the United States each year are tied to heat, according to the federal Centers for Disease Control and Prevention.

But those numbers account only for instances in which doctors specifically code the visit as a heat-related event.

Similarly, between 2004 and 2018, an average of only 702 heat-related deaths across the country were reported to the CDC.

“We know that’s a pretty gross underestimate,” Uejio said. “Our best scientific estimates are anywhere between 5,000 to 12,000 deaths in the United States due to conditions exacerbated by heat each year.”

Low reporting continues today, experts say.

Despite patchy reporting, it appears heat-related deaths are on the rise. Last year’s number of estimated deaths was more than double the number from a decade ago.

Medical schools must teach doctors to look for and document heat-related illness, said Holder, whose Florida Clinicians for Climate Action has held lectures for students and doctors on topics like the effects of climate change on patients.

Holder said she has seen how heat exposure over time harms the predominantly low-income and minority patients she served at her community clinic in South Florida.

There was an elderly man who had signs of worsening kidney function on days he worked long shifts selling fruit on hot Miami streets.

A mother whose asthma worsened as temperatures rose.

A Fort Lauderdale woman with chronic lung disease who was arrested for fighting with her daughter over a fan. She died three days after returning to her broiling apartment.

Making a city more resilient

In April, Tampa Mayor Jane Castor set a goal of planting 30,000 trees by 2030.

But Whit Remer, Tampa’s sustainability and resilience officer, said that target might be difficult to nail. Remer said trees are competing for space in the public right of way with sidewalks and utilities. Limited open land also poses a challenge. Tampa has no room for new parks, he said. So it’s about maximizing that finite green space.

“Planting trees has been the hardest thing that I have done as the city’s resilience officer,” Remer said.

He’s looking to other cities for solutions. In Phoenix, a “cool pavement” pilot program uses a water-based asphalt layer to reflect heat off roads. Last year, Miami-Dade County appointed the world’s first chief heat officer. Washington and Oregon have begun distributing thousands of air conditioning units to vulnerable residents and barred utility companies from cutting power to homes during heat waves.

Remer said Tampa is in its “learning and listening” phase. Last year, the city was awarded $300,000 by the National Academies of Sciences, Engineering, and Medicine to develop a guide for understanding and fighting the effects of heat in East Tampa, a predominantly Black neighborhood, in which at least one-third of children live below the poverty line.

Planting trees is helpful, according to project director Taryn Sabia, an urban designer and associate dean at the University of South Florida who focuses on climate resiliency work, which spans hurricane preparedness, flooding and increasingly extreme heat.

But it takes time for trees to grow and effort to maintain them. Quicker actions could include erecting better shade structures at bus stops or implementing rules for construction to encourage the use of materials that generate less heat in the sun. For example, some cities in the Northeast — including New York and Philadelphia — provide financial incentives for “green roofs,” in which the top of a building is covered with plants.

Another easy step: painting everything white. Light colors reflect sunlight, while dark colors absorb heat.

And while Florida codes require homes to have a mechanism to provide heat in the winter, they don’t require landlords to provide air conditioning.

“You can no longer be here and not have it,” Sabia said.

Tampa could better tailor weather advisories for specific needs and neighborhoods, she said. Heat becomes more dangerous more quickly on upper floors of older apartments, for example, because heat rises. Expanding access to cooling shelters is also key.

Under brutal sun amid little shade, Benjamin Brown walks home from an eye doctor’s appointment — about a 30-minute walk — along West Kennedy Boulevard in Tampa.

During the hottest week of the year in Tampa, Benjamin Brown, 75, was walking home from an eye doctor’s appointment — about a 30-minute walk.

There were few trees in sight, but Brown, who doesn’t have a car, makes a similar trek every day, running errands, visiting friends.

“It’s very oppressive. It does get to me,” Brown said, wiping his forehead as he continued down the street in the blistering sun.

Shade — any shade — would be a lifesaver, he said.

The Tampa Bay Times produced this story in partnership with KFF Health News, a national newsroom that produces in-depth journalism on health issues.