On the evening of August 22, 2024, Jeff Howard was preparing dinner at his home in northeast San Antonio, with local TV news playing quietly in the background.
“The story is developing now. Police found a homeless woman dead on the sidewalk,” the news anchor said.
When Howard saw this, he put down what he was doing and quickly approached the TV.
“The cause is believed to be extreme heat.”
Howard knew this was most likely because a high-pressure system called a heat dome had recently moved into south Texas. This meteorological phenomenon acts like a closed oven door, trapping billowing hot air underneath. The official temperature that day reached 106 degrees Fahrenheit (41°C) – 12 degrees above the average temperature for the day. The deceased was later identified as 46-year-old Jennifer Witzel.
Even though Howard didn't know her, Witzel's death hit him hard.
“Right here in San Antonio,” he said. “A specific person gave these numbers names and faces.”
Tragic example of growing trend
Howard is a professional digital expert. Howard, an associate professor of public health at the University of Texas at San Antonio, a 15-minute drive from where Wetzel died, specializes in using big data sets to understand the acute and long-term health consequences of various traumas.
That night, heat-related deaths were at the forefront of his mind. He is the lead author of a study to be published in JAMA. “Trends in Heat-Related Deaths in the United States, 1999-2023” is the first scientific paper to document a sudden and dramatic increase in heat-related deaths nationwide, which may be related to climate change.
The study found that heat-related mortality (deaths per 100,000 people) increased by 63% between 1999 and 2023. But the data show something more disturbing: The trend is rapidly accelerating.
“The death rate has increased by 117 per cent in the last seven years,” Howard said.
Sara Meerow is an urban thermal energy specialist at Arizona State University in Tempe, east of Phoenix in Maricopa County. Last year, 645 people died from heat in the county. Milo said hot deaths have long been considered a problem largely limited to the Phoenix metro area.
But Howard's study “suggests that the increase in heat-related deaths in Phoenix, Arizona, over the past few years is part of a national trend,” she said.
Miro, an associate professor in Arizona State University's College of Geographical Sciences and Urban Planning, was herself the lead author of a journal article published days before Howard's paper. Her report looks at what officials are doing — and not doing — to reduce heat-related deaths in the U.S.
Heatwave exposes gaps in protecting vulnerable communities
Although heat kills more U.S. residents than any other form of extreme weather, Milo noted, “heat is less visible and largely unregulated than other hazards, such as flooding.”
For example, Miró noted in the paper that the federal government maps flood zones, builds levees, subsidizes flood insurance, and provides financial and other assistance to people affected by flooding. But there are currently no similar measures to help U.S. residents who may suffer from deadly heat waves.
Jessica Wetzel’s death is a tragic and classic example of the failure of government officials at all levels to protect Americans from the sweltering heat.
Wetzel was homeless and diagnosed with a severe mental disorder. Living on the streets without access to cool shelter, people are more likely to suffer from heat-related illnesses, from temporary heat cramps to potentially fatal heat stroke. Mental disorders can interfere with a person's ability to recognize when their body temperature rises to dangerous levels. Across rural and urban America, there is a chronic lack of shelter beds for the homeless, air-conditioned spaces open to the public when needed, and mental health care for vulnerable populations who cannot afford health insurance.
READ: For homeless people in America’s hottest cities, heat waves are a relentless killer
Wetzel died at “ground zero” of San Antonio's urban heat island, where vast expanses of concrete combined with a lack of vegetation and shade cause already-high temperatures to spike. Waste heat from gas-powered vehicles is a significant contributor to urban heat islands, and Interstate 10 is less than 1,000 feet south of where Wetzel was found. To the north, even closer, is a massive concrete parking lot that serves the city's 500-bus transit system.
How hot it was when and where Wetzel was discovered is unclear, but Greg Harman has a pretty good idea. Harman is the founder of Deceleration, a nonprofit online journal based in San Antonio that describes its beats as “the intersection of environment and justice.” During the hot summer months in San Antonio, Harman traveled to different neighborhoods, documenting and writing about the different effects of hot weather on residents in different locations.
The day before Wetzel died, Harman used extremely precise tools to measure the temperature and humidity in downtown San Antonio. The official high temperature for the day was 108 degrees (42°C), but the reading was taken at the airport, a few miles from the city's hottest city centre.
“The temperature in the city center is as high as 119 degrees [48°C],” Haman said. “The heat index, which combines heat and humidity to determine how hot the human body feels, is 129 degrees [54°C]”.
Heat-related deaths underestimated
Witzel's death also highlights what experts agree is a fundamental problem in reducing heat-related deaths.
“We’ve known for decades that official heat-related deaths are grossly underestimated,” said Kristie Ebi, a professor of global health at the University of Washington. She added that without understanding the true scale of the problem and other Without details, it is difficult to prioritize actions.
Abby points to several factors that contribute to these undercounts, starting with the lack of national standards for reporting heat deaths. For example, Bexar County, Texas, which includes the city of San Antonio, does not track heat-related deaths, which means Wetzel is unlikely to be included in state or national heat mortality statistics regardless of the cause of death on her death certificate. .
This points to another problem: Death certificates are not necessarily reliable indicators of heat death.
“Extreme heat can cause heart attacks,” Abby explains. “If someone comes into the emergency room with a heart condition, the staff there may not know if that person was exposed to extreme heat.”
If the patient died, the cause of death was recorded simply as heart attack.
Another reason a death certificate may not mention heat is that there are no state or federal standards for who can issue a death certificate.
Read: Climate change could kill tens of thousands in 2023
In Texas, professional medical examiners may be available in large urban areas. “But in smaller cities and rural areas,” Howard said, “the person filling out the death certificate might be a justice of the peace who has no medical training at all.”
This may partially explain why the Phoenix metro area has such a high percentage of reported heat deaths (plus it's a sprawling, car-centric desert city).
“The Phoenix Medical Examiner's Office has rigorous protocols in place to identify heat-related deaths,” Howard said.
In short, if you're actively looking for heat-related deaths, you're likely to get a more accurate count than if you're not looking. Given the sharp rise in heat deaths recorded nationwide in Howard's study, he believes getting a more accurate count is critical to taking action to save lives.
“Going forward, there should be a more concerted national effort to develop more standardized protocols and processes for assessing heat-related deaths,” Howard said.
At a vigil held days after Jessica Weitzel's death, one of her childhood friends put it succinctly. Marisol Cortez stood under an umbrella in the strong Texas sun and spoke to a small group of family and friends gathered near the site of Witzel's death.
She said these words to government officials.
“Count the bodies!” asked Wetzel's friend.
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