A new investigation shows heat is even deadlier than we thought

Hot weather isn’t just an inconvenience. It’s killing thousands more Americans than show up in official records. That’s the finding from a new NPR investigation, in partnership with Boston University. And the way they came up with that new, better estimate of the true toll of heat is, of course, with science. This episode, we’ll bring you all the details – and chat about why getting good estimates could save lives. Interested in more science-based investigations? Email us your question at [email protected] mailto:[email protected]. Support public media with NPR+ and enjoy perks for over 25 podcasts like this one. This show’s perks include sponsor-free listening. Learn more at plus.npr.org http://plus.npr.org/. See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

• 0:00Speaker 00

  This message comes from Planet Visionaries. Host Alex Honnold sits down this season with extraordinary doers creating real climate solutions. Listen or watch wherever you get your podcasts. You're listening to Short Wave from NPR.

• 0:17Speaker 01

  Short wavers, Nate Roth here, and I am thrilled to say that it is almost fall. Because I don't know about you, but for me, this summer has felt unbearably hot, like many before it.

• 0:30Speaker 02

  This summer has seen deadly heat waves across the US. Been caused by severe drought and record breaking heat.

• 0:35Speaker 01

  Heat wave continues to make life miserable.

• 0:38Speaker 03

  Excessive heat warnings. Of extreme heat. Or extreme heat.

• 0:42Speaker 01

  My friend and colleague, Alejandra Barunda, lives just up the coast from me here in Southern California. And Alejandra, I know that you've been feeling this heat too, because we've complained about it together.

• 0:50Speaker 04

  Yes, we have, Nate, and I can say that I have never been more grateful to have a heat pump that cools our house.

• 0:57Speaker 01

  I'm grateful that you have that. As a climate correspondent at NPR focused on the intersection between human health and our warming planet, extreme heat is squarely in your beat.

• 1:07Speaker 04

  Yeah, and as I've been reporting on it for the last couple of years, I noticed this problem. We, as a country and as a world, aren't keeping accurate track of how many people are getting sick or dying from heat. And that means that it's been really hard to get people to care in a meaningful way and like, do anything about it.

• 1:29Speaker 01

  Yeah, that makes sense. I'm looking at one of your stories right now, and you say the official number from the Centers for Disease Control, the CDC, is about 1,700. So on average, 1,700 people die each year from heat. That was over the last eight years. But you had an inclination that that number was low?

• 1:46Speaker 04

  Yeah, I really did. And I want to be clear, a low estimate is not really the CDC's fault. The way that we count and track causes of death in this country vary from state to state and even county to county, and CDC is kind of compiling all of those numbers. So the problem stems from somewhere deeper. This is just really hard to do.

• 2:05Speaker 01

  But Alejandra, being the enterprising reporter that you are, you decided to come up with a better estimate.

• 2:12Speaker 04

  Yes. This was a huge, probably slightly over ambitious project, and it took a couple of years. And I really could not have done it without partnering with epidemiologist Quinn Adams at Boston University. And together, we found that we, as a country, are undercounting the number of people that die from heat and heat related issues by a factor of about five.

• 2:37Speaker 01

  Whoa, so meaning the real number is actually five times higher?

• 2:40Speaker 04

  Yeah, our modeling suggests that it's something like 9,000 people that are dying from heat each year. And even that might still be an underestimate.

• 2:52Speaker 01

  So today on the show, why the US is vastly undercounting the deadliness of heat, not just in states like Texas and Florida, but places like even the Northeast.

• 3:01Speaker 04

  And how some of those places are trying to do better to save lives.

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  You're listening to Short Wave, the science podcast from NPR.

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  This message comes from Planet Visionaries, the podcast celebrating the people creating practical, hopeful solutions for the planet's urgent conservation challenges. Hosted by legendary climber and advocate Alex Honnold, each episode goes beyond the headlines to show it's actually working and who's making it happen. In partnership with the Rolex Perpetual Planet Initiative, this is Planet Visionaries. Listen or watch wherever you get your podcasts.

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• 4:34Speaker 01

  Okay, Alejandra, I want to get into the numbers and all the fancy statistics that you did, but just from the outset, I want to highlight that these are actual people we're going to be talking about, right?

• 4:44Speaker 04

  Yeah, and a lot of their stories were just absolutely heartbreaking. And they really stuck with me. And one of the reasons why was because a lot of them were so, so avoidable. Like, one thing I heard over and over was about how someone's AC or swamp cooler would break, and they couldn't afford to fix it. And then that turned into an actual death sentence. And that's what happened to Sherri Petty. She was a woman who lived in Tucson, Arizona, and her daughter Tara Getner told me about it.

• 5:15Speaker 06

  But I woke up covered in sweat.

• 5:20Speaker 06

  I went to the kitchen to get a drink, and my mom's laying there on the floor in front of the swamp cooler that's blowing hot air and a rotating fan that's blowing hot air.

• 5:32Speaker 04

  The house was boiling hot, and Sherri Petty died later that day. Tara is still totally consumed with grief a year later.

• 5:41Speaker 01

  Oh, man.

• 5:42Speaker 04

  And I want to be clear here, Sherri's death actually was counted because it was so obviously affected by heat. But there were a lot of other people I talked to who went through something similar and whose loved ones' deaths weren't counted.

• 5:55Speaker 01

  So most of the 9,000 heat related deaths in your analysis, they're not Sherri's. Like, they're not people that were counted, right?

• 6:01Speaker 04

  Right, exactly.

• 6:02Speaker 01

  Okay, so were you surprised that that number came back as 9,000?

• 6:07Speaker 04

  Yeah, it's a really good question, and it's been interesting to wrap my head around because it's sort of a small number and a big number at the same time. Like, compared to the death toll of something like cardiovascular disease, which is the leading cause of death in the country, it's not huge. But it's a big number because, well, like we said before, it's way more than we knew, five times higher. And it's way, way more than is officially reported for other kinds of natural disasters like hurricanes or wildfire. Though I will say that there's also a lot of new research showing that those are also likely way undercounted.

• 6:42Speaker 01

  So what I'm hearing here is that we have an undercounting problem in this country?

• 6:45Speaker 04

  Yeah.

• 6:46Speaker 01

  When we were talking about heat, though, like, why, why is that?

• 6:49Speaker 04

  Yeah, I mean, I think it's because it's genuinely hard to count well. It's really easy to miss and hard to count, heat deaths. And that's mostly because heat isn't usually the only thing that kills someone.

• 7:05Speaker 01

  Yeah.

• 7:06Speaker 04

  A lot of times, heat is a part of the story, not all of it. It's the trigger for something like a heart attack or a kidney failure. But if you're not looking for it, it's really easy to miss. This one doctor in Arizona, Brian Drummond, kind of explained it to me like this. He's, he's super aware of the problem. And he's still like, it is hard for me to determine for sure that heat played a role in someone's death. And he'd need to be absolutely sure heat played a role in order to put it on a death record. And that means that he has to do the kind of like investigative interviews before someone dies, and that's not always possible.

• 7:41Speaker 07

  So if I never ask a patient, were you exposed to extreme heat, or do you have the ability to cool where you live? If I'm not asking those questions, I would never diagnose them with heat related illness unless their temperature came in at 105.

• 7:54Speaker 01

  Oh, that is so tricky.

• 7:56Speaker 04

  And the other part is that, you know, there's a lot of different people in this country who end up certifying deaths. Doctors do some of them, medical examiners do some, coroners do others. But all of those people are trained really differently. And for example, some coroners are elected and don't actually need any experience or credentials.

• 8:14Speaker 01

  Oh, wow.

• 8:14Speaker 04

  And there's also not really a standard way to do a heat investigation. And all that means that I honestly, I don't think we're ever going to have a perfectly accurate number. And that, to me, is why these sorts of statistical estimates, like the ones that we did here, are so important. They help us see kind of a truth that is not simply the fact written down or not on a death certificate.

• 8:39Speaker 01

  Okay, so let's get into this actual analysis. What was the process you used to figure out a number that's closer to reality?

• 8:47Speaker 04

  Great question, Nate. So basically, what we did was some fancy modeling to calculate something called excess mortality. And you might remember that term because it was similar to what public health officials were doing to estimate COVID deaths back in the middle of the pandemic.

• 9:03Speaker 01

  Oh, yeah.

• 9:03Speaker 04

  And how that works is basically you figure out an estimate of how many people are expected to die in a place in any given week. And then you see how many people actually died. And then our modeling figured out how much of that difference was attributable to heat. Here's Quinn Adams. She's our lead partner at this, and she's explaining the process a bit more.

• 9:22Speaker 08

  This is maybe a little bit jargon-y, but we essentially did this like county specific model in which we Basically come up with an exposure response function where we can say like, at these temperatures, this is your risk of death at each temperature.

• 9:40Speaker 04

  So basically, we took into account things like where the deaths were because heat hits differently for someone in like Massachusetts than it does for a Texan, based on what their bodies are used to.

• 9:51Speaker 01

  Yeah, that makes sense.

• 9:53Speaker 04

  Yeah, and people do acclimate to the heat in the place they live, like up to a point at least. But I also really want to point out that like, I think a lot of times we think that it has to be like extremely hot to hurt people, like 100, 110. And that's not true. There's a lot of cases in which, you know, it can be 85 out and someone is going to have the same impacts. For example, there's a lot of common medications that make you more sensitive to heat or not able to sweat effectively. And all kinds of stuff that makes your thresholds a lot lower.

• 10:26Speaker 01

  Whoa, I had no idea about that. I mean, and I get it. Like, I've complained about our temperatures here on the coast all summer, but the humidity and heat index that we have been having is like a normal summer day in a place like New Orleans or something.

• 10:40Speaker 04

  Yeah, and different places have different relationships with heat because of that. And also, preparedness is different.

• 10:46Speaker 01

  Yeah.

• 10:47Speaker 04

  We also looked at something called a lag. Say you have a heart condition and it gets really hot and your body can handle that for a few days, but it's getting more and more stressed over time. It might not be until a few days later that something happens and lands you in the emergency department or even worse, dead.

• 11:05Speaker 01

  Or the morgue, yeah.

• 11:06Speaker 04

  Right, exactly. But it was still the heat that led to something happening. And so our model takes that lag between the heat and kind of the incident into account.

• 11:17Speaker 01

  Do you feel good about this number? Like, is it possible that this is also an undercounting of the true scale of what's happening?

• 11:23Speaker 04

  This is definitely a solid first step. But Quinn and I agree.

• 11:28Speaker 08

  This is the best possible estimate that we have, given the most up to date methods and the best publicly available data. But it's still an expected underestimate.

• 11:41Speaker 04

  We were actually in the process of getting access to some finer scale national death data that would help us get an even better estimate. And we think that using that even finer scale data set would probably end up giving us a higher estimate. But we have not yet gotten access to that. We are still trying.

• 12:00Speaker 01

  OK, so stay tuned.

• 12:01Speaker 04

  Yeah.

• 12:01Speaker 01

  So, Alejandra, I know we're both journalists. Like, we don't make policies or decisions for people. You know, we, we report the news and we give the public information. But I feel like after spending so much time on this, like, you have to have some hope that something comes from this, right? Like, what would that be?

• 12:20Speaker 04

  Oh, man, Nate, that's such a good question. Thought about this a lot. Um, and I think the first thing is honestly just awareness. You know, like, I truly think oftentimes people think heat is just a nuisance or like an inconvenience.

• 12:36Speaker 08

  Most people do not see themselves as vulnerable to heat. They're like, oh, that's someone else. It's not me. But then, you know, push comes to shove, and it actually is you.

• 12:47Speaker 04

  And we're learning all kinds of stuff about what heat does to your body. Like, it can age you, like smoking does. And these kinds of physiological impacts really make it clear that it can hasten deaths in a meaningful way. And that's for people everywhere. And that leads me to something else that came up when I was talking to this scientist, Patricia Solis, from Arizona State University. She said, we treat heat as a, quote, "me" problem, when really, it's a, quote, "we" problem.

• 13:20Speaker 01

  I mean, yeah, that, that tracks.

• 13:22Speaker 04

  Yeah, exactly. Like, we tell people, oh, man, like, take care of yourself. Go inside, like, make sure your AC is running. Make sure you cool down. But like, this is a policy problem, right? And I hope policymakers hear this and agree that it's a "we" problem. There's so many structural things that we could address that might help keep people safer. And it's sort of shocking how many cities or counties or states don't have, like, real, solid action plans to address heat just yet.

• 13:54Speaker 01

  Are there places that are doing a better job than others, though?

• 13:57Speaker 04

  Oh, yeah, definitely. And at the top of that list are places in Arizona, like Maricopa County or Pima County. And that makes sense, right? Because Arizona is like in the epicenter of the heat crisis. Yeah. And so they're putting a ton of effort into better tracking heat deaths. In fact, those counties both counted more heat-related deaths than our model predicted.

• 14:16Speaker 01

  Oh, man.

• 14:17Speaker 04

  But I will say, my reporting also found many people who weren't included in those official counts. So to me, that says both the model and the medical examiners are probably still undercounting. But I will say that Arizona and like the counties and cities within Arizona are doing a lot to experiment with ways to keep people safer. For example, there was this rule that was keeping people from having outward-facing air conditioners sometimes when their landlords didn't want them to because of like aesthetics. And the state was like, no, no. If you need an air conditioner, you can have one, even if it like, you know, affects how.

• 14:52Speaker 01

  Doesn't look great.

• 14:53Speaker 04

  Yeah, exactly.

• 14:53Speaker 01

  Yeah.

• 14:54Speaker 04

  And I will say, like, places like New York State and City are experimenting, for example, with moratoria, where utilities aren't allowed to shut off people's power for non-payment during heat waves.

• 15:05Speaker 01

  Same thing that we have in winter to keep people from dying from cold.

• 15:08Speaker 04

  Yeah, exactly. And so like, now it's clear that we need to figure something out like that for the summer as well. But it's still a pretty new approach in many parts of the country.

• 15:18Speaker 01

  Hearing this list of all the places that are trying to address heat, I feel like it's just like an almost overwhelming problem. It's a really hard thing to fix.

• 15:25Speaker 04

  Yeah, and you can't fix a problem until you know about it. And you don't know if your solutions are working unless you're keeping track of them. And so I just really hope this work can help with both of those things.

• 15:38Speaker 01

  Alejandra, I hope so, too. Thank you so much for bringing us all of this work and for doing it.

• 15:45Speaker 04

  Yeah, thanks for talking about it. And just for anyone who wants to look deeper at the model, we made it open source. You can take a look. We'll drop a URL in somewhere.

• 15:54Speaker 01

  This episode was produced by Burley McCoy. It was edited by Rebecca Ramirez. Tyler Jones checked the facts. The audio engineer was Jimmy Keely. I'm Nate Rot. Thanks for listening to Short Wave from NPR.

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