Calculating the damage from a hurricane or wildfire is straightforward: simply add up the cost of destroyed buildings, disrupted business and livelihoods lost.
For extreme heat 鈥� the kind that has gripped South Florida and much of the nation for months now 鈥� the toll is harder to tally, because the real danger of heat isn鈥檛 to homes and power lines, it鈥檚 to human health. And, experts say, the official numbers likely don鈥檛 capture the whole picture.
This summer鈥檚 record-breaking, unrelenting heat has already claimed at least one life, according to friends and advocates of a 29-year-old farm worker who collapsed on a Homestead fruit farm in July. Fire rescue in Miami-Dade also has noticed an uptick in 911 calls for heat exhaustion and heat stroke compared to last summer, which was less hot. June through mid-July of last year, the department received 86 calls. This year, they got 99.
But more complete official records, including a daily count of heat hospitalizations and deaths in South Florida, are harder to come by. Local hospitals declined to provide to the Miami Herald their own count of heat hospitalizations and deaths. The state does track it for some counties, including Miami-Dade, but the Department of Health did not immediately respond to a request for data.
However, several doctors at hospitals around the county say they haven鈥檛 seen more patients struggling with the heat, despite a near-daily drumbeat of high-temperature records being shattered.
鈥淚 haven鈥檛 heard about a whole lot more deaths,鈥� said Dr. Cheryl Holder, interim executive director of Florida Clinicians for Climate Action. 鈥淭his is a good thing.鈥�
Heat is hard to measure
But many experts, including Holder, believe heat-related illnesses and deaths are almost certainly under-counted both in Florida and nationwide. One major reason is the way the medical industry keeps records.
Heat affects the body in a number of ways, including some that scientists are still discovering. Besides the obvious direct links, like heat stress and heat stroke, high temperatures can worsen heart and lung conditions, chronic illnesses like Lupus, diabetes and asthma.
But when someone is hospitalized for one of the conditions that are worsened by heat, their provider typically records only the chronic illness, not heat.
鈥淲hat you end up with is a correlation that never proves causality, or you end up with not the strongest numbers,鈥� said Holder. 鈥淎nd it seems like it is not an important number because it鈥檚 low.鈥�
Perhaps the best example of how yawning the gap is between the official number of illnesses and deaths reported and what researchers project as a more likely impact can be found in a health report Miami-Dade commissioned last year. Miami-Dade鈥檚 medical examiner鈥檚 office has officially recorded only two deaths directly linked to heat in the last five years. But researchers reviewed all excess deaths in the county during that time and concluded the real annual average could be much higher: 34 deaths 鈥� every year.
Long-term trends of hospitalizations, emergency room visits and even deaths due to heat have varied wildly in Florida in recent years, with no clear trend upward or down through at least 2021, the most recent year data is publicly available. They鈥檙e also heavily affected by storms. After hurricanes, when power is out and people are stuck in the heat, hospitalizations and deaths tend to rise.
Miami-Dade鈥檚 heat vulnerability study found an average of 58 hospitalizations and 301 emergency department visits a year for heat-related illnesses specifically. But that kind of information is not reported by every county, making it even harder to calculate the impact heat has on Floridians鈥� health.
But even by the state鈥檚 measure, there鈥檚 a connection between high temps and more sick residents.
A found that as the temperature and heat index rose, more people visited the emergency room for heat-related illnesses like heat stress and heat stroke.
鈥淎s both measures of exposure increased, rates of heat-related illness increased significantly,鈥� the state report said.
And nationally, heat-related deaths have been increasing since 1990, according to Centers for Disease Control data reported by the Guardian. Average annual heat-related deaths rose 95% from 2010 to 2022, .
Another complicating factor for Florida: Unlike other places, which usually experience extreme heat in the form of a clearly defined heat wave, the Sunshine State is hot year round.
鈥淲e are always hot, to a certain degree. So how much is acclimatization going to confound the data?鈥� asked Holder. 鈥淣o one has ever really studied chronic heat exposure. When it comes to heat like that, you don鈥檛 have a sizable data set in the past.鈥�
And unlike other places, Florida has been hot for a while. So most people have homes, cars and even workplaces with air conditioning and have easy ways to stay safe when it gets unbearable outside.
These pre-existing protections, and the fact that human bodies can 鈥� and do 鈥� acclimate to the heat, is why some doctors think hospitalization and deaths are relatively low, despite record heat.
鈥淲e don鈥檛 tend to see as much as one might think,鈥� said Dr. Hany Atallah, chief medical officer at Jackson Memorial Hospital. 鈥淥ur population here, they know fairly well what to do.鈥�
Counting Deaths
Tallying the worst case of extreme heat 鈥� death 鈥� is just as difficult, if not more so, experts say.
Chris Uejio, an associate professor at Florida State University and lead author of Miami-Dade鈥檚 heat vulnerability study, said a coroner can only classify a death as heat-related if the core body temperature of the deceased person is elevated. That rules out bodies discovered a while after death.
Classifying heat deaths also runs into the same problem as classifying heat-related illnesses: if someone dies of a disease or condition exacerbated by heat, the disease is what鈥檚 listed on the death certificate.
That鈥檚 why Uejio and other heat action advocates in Miami-Dade partnered with Baptist Hospital to hold training sessions for local clinicians to explain the connections between heat and health issues, as well as train them to better record heat-related illnesses and deaths.
鈥淚 think it鈥檚 underappreciated to some extent how widespread and common heat is as a public health problem,鈥� Uejio said. 鈥淲e know this is going to be a continual threat and a bigger one going forward.鈥�
Uejio was the researcher behind Miami-Dade鈥檚 new annual average heat deaths estimate 鈥� 34. He used a statistical analysis that took into account all deaths in the last five years and came up with a much higher number that he said better reflects the real toll of extreme heat in Miami-Dade.
To illustrate how heat deaths get under-counted, consider the case of Efra铆n L贸pez Garc铆a, a 29-year-old farmworker who collapsed and died while working on a farm in Homestead on July 6, when the heat index hit 106 degrees.
L贸pez Garc铆a鈥檚 death was quickly and widely reported 鈥� but only because of the efforts of the Florida Farmworker Association. A day after L贸pez Garc铆a鈥檚 death, a Farmworker Association staffer saw a post about it on Facebook. Another staff member, Claudia Gonzalez, searched through the Farmworker Association鈥檚 member rolls to find people with matching last names and cold-called them until she found L贸pez Garc铆a鈥檚 cousin, who told her his brother had been with L贸pez Garc铆a when he died.
鈥淭he same day that we found out about [L贸pez Garc铆a鈥檚] death, we found his family and we made a report to OSHA,鈥� Gonzalez said. 鈥淚t鈥檚 about knowing the community. All of that would have been impossible if the community didn鈥檛 come to us.鈥�
Had the Farmworker Association not investigated, the story may not have been widely known. 鈥淭hese are deaths that we don鈥檛 hear about,鈥� said Yvette Cruz, a spokesperson for the Florida Farmworker Association.
鈥淚 think it鈥檚 grossly under-reported,鈥� said Doug Casa, who heads research on heat illness at the University of Connecticut鈥檚 Korey Stringer Institute. 鈥淟aboring in the heat is one of the main reasons to have cardiac events鈥hen a worker dies in the heat of a cardiac event, it鈥檚 getting recorded as a cardiac event, it鈥檚 not going down as the heat that caused it.鈥�
鈥淚f a person鈥檚 not a U.S. citizen or they鈥檙e working here illegally, we鈥檒l basically never hear about those cases,鈥� Casa added.
This climate report is funded by Florida International University and the David and Christina Martin Family Foundation in partnership with Journalism Funding Partners. The Miami Herald retains editorial control of all content.
