Climate: Fighting Extreme Heat In 2026

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0:24Extreme heat isn't just an inconvenience, it's a growing public health threat. More than 40 million people across the U.S. have remained under heat alerts this month. Heat remains the deadliest extreme weather event in the United States. And in Europe, heat waves killed more than 10 ,000 people in June. That's according to just published health data published from 27 countries. Climate change is making heat waves hotter and more frequent, and high temps aren't just being reported in the daytime. Nighttime temperatures are higher than ever. And scientists say that's raising the risk of heat exhaustion and heat stroke and taking away crucial time for you and the planet to recover.

1:05So what do you need to know about the effects of heat on your health and how you can stay safe? And what are cities and states doing to fight the heat? I'm Nyla Boodoo in for Jen White, and you're listening to the 1A podcast. We'll get into all of that today, starting with one county that's focusing on fighting extreme heat from the top. That's after this.

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2:08So listen to the Fresh Air podcast from NPR and WHYY. Let's jump into the conversation with our first guest. Mayor Daniela Levine-Cava is Democratic mayor of Miami-Dade County with a population of almost 3 million. Mayor Levine-Cava, welcome to 1A. Thank you so much, Naila. Let's start with a chief heat officer role that you created a few years ago. How did that position come to be? Why did you see a need for this? It's the first one ever created. I have to give credit to Adrienne Arsch, who is a philanthropist and very involved in climate change issues. And she actually brought it to our attention.

2:47And we said, absolutely, we need to do that because, after all, we are the heat capital in so many ways. So we did appoint the first in the world, and we have been a national leader and an international leader since then. I co-chair the Climate Mayor's Extreme Heat Cohort. We've created an Extreme Heat Action Plan that has made incredible progress and is modeled across the city and the country and the world. and we are moving forward and making great progress in reducing heat-related effects. So I know that position was launched in 2021, although it doesn't exist anymore. It was eliminated as part of budget cuts last year.

3:32How is that work being done now? Yeah, so in actual fact, our chief resilience officer is also our chief heat officer. So we haven't eliminated it, but the founder, Jane Gilbert, did retire. She, again, global leader. And we also have a dedicated staff person who is our coordinator and who is maintaining our focus on this work. What does it mean from a government spending level in Miami-Dade County to focus on heat resistance? What does that look like? Yeah, so we are doing so many things. We created a heat season. We have cooling centers, 60 around the county, so we leave buildings open during the heat season.

4:21We give our staff access to not just water and breaks and shade, but those who are exposed. We give them electrolytes so that they can maintain their body healthy while working outdoors. So all of those things do cost money. We also have the staffing, as has been described, and we reduce our energy through all kinds of resilience measures. We've done so much to make our buildings more efficient, and that is good for the environment, and it's good for the budget as well. Mayor, I wanted to play this voicemail we got from Alex. I believe trees are some of the best ways we can adapt cities to climate change and mitigate the negative effects of heat.

5:08My concern is as we try to make more room for trees, we're still competing with cars that seem to dominate our cities and have ample parking. I would like to see cities reduce parking and narrow streets to allow more connected green space while reducing the impervious pavements that hold heat well into the night. Mayor Levin Kava, I wonder how you would respond to Alex's message there. I would say as a native Miami and I know how much people love cars across the city, How are you thinking about city infrastructure when it comes to fighting heat in Miami-Dade? Well, first let's talk about trees because trees absolutely are essential.

5:43They can reduce ambient temperature by as much as 10 degrees. So we have been very aggressively planting trees. Last year alone, we gave away 25 ,000 trees. So we have regular tree giveaways and particularly in the neighborhoods with lower tree canopy. So that is a critical part of it. We also, of course, are pushing transit. Transit is much more efficient. It has lower emissions, so it's overall helping climate as well as traffic. So those are a few of the ways that we're addressing it. I mentioned nearly 3 million people live across the county. We've all probably heard of the idea of extreme heat islands.

6:25Can you explain how in Miami some neighborhoods are more unequal than others when it comes to how people are experiencing extreme heat? Yeah, as I said, you've got lower income communities, sadly, are often those with the lower tree canopy. So we've been targeting our tree giveaway and our tree maintenance in those neighborhoods and actually providing support for how to take care of those trees. Also, removal of large trees is very much discouraged. And we've also started relocating large trees. If infrastructure projects require their removal, we are working hard and have been working with some fantastic vendors to move them so that we do not lose the overall benefit of that.

7:15We also have done a lot to bring more cooling to those neighborhoods. So the cooling centers, I mentioned 60 that are across the county. We also, for example, in our public housing, installed 1 ,700 high-efficiency cooling units through dollars from the infrastructure bill in the previous administration. So we also have shaded now bus stops. That's critically important. We want people to use transit, but they're exposed to the elements, including heat. So we have launched an aggressive campaign to provide shade for those who have to wait in the elements for their buses. Mayor, you mentioned the previous administration.

7:59Are you getting the support from the federal government as well as from Tallahassee and state government for these different implementations that you would like to have across the county? Well, I will say, sadly, the state legislature preempted us from heat standards, standards for workers, other than our own county employees who we do protect. But fortunately, we've been able to raise awareness with our public education campaigns. And we have hundreds of companies that have come to us for training and education and utilizing our tools how to protect their workers with shade, water and rest. We got this text message.

8:39I work outdoors at parks in Miami-Dade County. Some parks have put out big barrels of cool water with cups for the attendees. Other hosts have made sure lots of coolers full of bottles of water were available. In the past few years, I've been at events and patrons have passed out. EMS has to be called. I passed out once at home. I believe I was experiencing dehydration. I now make a simple concoction of water, a tablespoon of lemon juice and orange juice and salt and sip on that throughout the event. Mayor Levine Cava, when you think about the culture, particularly around workers and what employers need to do, you mentioned that you have tried to set a standard with county workers.

9:19What other conversations do you have with major employers, especially as people are working outside to protect them? Yeah, so definitely we've been very successful with a lot of our employers adopting voluntarily, because we're preempted from mandating, the kinds of protections that this person has mentioned. But as well, we're very aggressive with our hydration stations. So water is life is our theme for our water and sewer department. We go with dispensers of water from the tap, right? We're avoiding water bottles. We don't need those. We want people to bring their own containers. And of course, if they're using bottles to recycle.

9:59But I'll give you an example. World Cup, we just had seven games. And during that time, most of the games were on days of extreme heat. In fact, the first extreme heat day was on the first day of World Cup, June 15th. We have been so successful in preventing serious illness from heat. We distributed about enough water in cups to about 20 % of the game attendees across the games the whole season. And that, unfortunately, they were not allowed to bring more than a small water bottle. And, of course, it costs money at those stadiums to purchase. So we were very pleased. We had cooling stations and people availed themselves of that.

10:43And we were able to greatly reduce any injury both at the games and at our Fan Fest. You know, when you think about South Florida, I think hurricanes are sort of the natural disaster that gets encoded into people's DNA. Tropical storm Bertha is making its way across the Gulf as we speak. How do you think about heat waves as part of your overall natural disaster strategy? And how are you trying to help people recognize this can be a serious problem? Yeah, we added heat to our trifecta, hurricanes, floods, and heat. So what used to be our annual hurricane season is now all three. And we use that for public education, awareness, prevention, just as you say.

11:24We also worked with the National Weather Service to signal extreme heat at a lower temperature, given the extreme humid conditions in our environment. So all of this is designed around increasing awareness. Look, when we started this with the first extreme heat officer, people laughed. They thought it was a joke, but they're not laughing anymore. That was Daniela Levine-Cava, Democratic Mayor of Miami-Dade County, Florida. Mayor Levine-Cava, thank you for being with us. We appreciate it. Thank you. We got this from another listener in Florida. I plant native trees and bushes here in South Florida, and my property stays about 15 degrees cooler most days.

12:07I find it pleasant to garden any time of day. If people did not remove trees and did not let developers remove trees, then the land will take care of itself. Coming up, the effects of heat on your health. What do you need to know and how can you stay safe? Stay with us.

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13:07Listen to NPR News Now on the NPR app or wherever you get your podcasts. Now, let's turn to the effects of extreme heat on our bodies and what you can do to stay safe with some new guests. Joining us now is Amruta Norisarma. She's an environmental epidemiologist studying climate change and health and an assistant professor at the Harvard T.H. Chan School of Public Health. Amruta, welcome. Thank you for having me. And Jeeva Lang is also with us. She's a staff writer at Heatmap News. Jeeva, it's nice to have you as well. Hi, excited to be here. Jeeva, I was just mentioning we just spoke with the mayor of Miami-Dade County.

13:47I just wondered your thoughts about what she said about cities, climate resilience, the idea of having someone actually at the county level focusing on this. Yeah, I think this is really important work. And Miami is such a leader in this area. And I think there's other cities, too, that are doing great work in this area as well. The two that come to mind are Spokane and Portland have been pursuing temperature maximums for renters. Renters tend to have the lowest AC access compared to homeowners. And that's been a really exciting method of pursuit for those cities to protect people from the extreme heat.

14:33But I think the big takeaway here is just that we need to be taking heat more seriously. whether that's protections for people at home or protections like you were discussing, the urban heat effect and the tree canopies protecting people in that way. Amrita, do we know yet as we see cities taking more action if there's a way to determine if that is leading to fewer heat-related emergency room visits? Yeah, this is a great question. And I think that it's a little bit challenging because there's obviously some lag between when the heat wave happens and when we get back information. So we might have to wait for a couple of weeks to know whether or not the strategies were effective.

15:16But we are starting to get information quicker and quicker regarding emergency department visits and hospitalizations associated with heat. We're also starting to see signals in some of the more nontraditional health outcomes that are associated with extreme heat. So you might think of heat stress or heat stroke as some of the more obvious directly related pathways. But we're starting to see things like dehydration illnesses, renal insufficiency. We're seeing some patterns in terms of changes in the ways that people respond for those health outcomes as well. So I think looking beyond just the traditional health outcomes is a good way that we can start to see those signals sooner as well.

15:56Jeeva, it's been a few weeks since the July 4th weekend, which we saw record-breaking heat waves throughout the country. More than 20 cities broke heat records this month. We know temperatures are rising year after year as a result of climate change. What factors are behind this summer's extreme heat that we need to know about? Yeah, great question. June 2026 was the second warmest globally, and it was the hottest ever for Western Europe. I think when you look at the headline number for the United States, it's the 18th warmest June in the contiguous United States. It doesn't sound very extreme.

16:32But what we're seeing is these prolonged severe heat domes. So those highs are really, really high. Like you were saying, there were, I think, 1 ,300 heat records matched or broken over that Fourth of July weekend. And that's just, again, because of greenhouse gas emissions and also likely a strong El Nino. We're still figuring out exactly what mechanism is at play for the heat here. But the greenhouse gas emissions make the entire atmosphere warmer. That means we're starting at a warmer baseline. So these highs can get really, really high as a result of that. Jeeva, I wonder if you can just help us understand, we've used the term extreme heat a few times now.

17:09Can you define that for us precisely in how it's categorized? Yeah, it's a hard question to answer because extreme heat is so contextual. Extreme heat for people in the South is very different than extreme heat for people in, say, the Pacific Northwest or people in Northern Europe, these places that haven't seen extreme temperatures before. So there isn't really like a number or a threshold that you have to break in order to have extreme heat or not. It's really about how much does this diverge from the historic norms in this area. So, Amrita, you talked about heat-related emergency room visits.

17:46Around 120 ,000 were recorded across the U.S. in 2023. That's according to the CDC. At what temperature and under what temperature conditions does the heat become particularly dangerous for our bodies? And I imagine, of course, there are caveats to people who are much more vulnerable than others. Yeah, that's a really good question. And I think going back to one of the things that Jeeva was saying a few minutes ago, it's so contextual because extreme heat, it means something different if you're in the northern part of the U.S. compared with the southern part of the U.S. Some of that is also about adaptation that's already been implemented in different communities.

18:25So, you know, homes in the southern United States might have air conditioning, for example. So the ambient temperatures might have less of an impact until the temperature gets much more extreme. But generally speaking, once we see a combination of heat and humidity that's above about the 95th percentile of whatever is normal for that area, that's when we start to see these really sharp increases. And we think of that as a more extreme heat period. And we start to look at comparing increases in some of those severe cases of heat-related illness around that threshold. What does the 95th percentile mean?

19:03Again, it means something different if you're in the southern U.S. compared with New York or Boston, for example. What are some signs people should look out for that might signal heat exhaustion or heat stroke? And what's the difference between those two, Amrita? Yeah, so heat exhaustion is maybe I could call it a little bit of a less extreme version of heat-related illness. It's where people start to feel tired. Your body is no longer able to sweat, which is one of the primary ways that we kind of cool off when it's very hot outside. By comparison, heat stroke looks very similar to a regular stroke.

19:44It's dizziness, it's a kind of loss of speech patterns, it's, you know, changes in your ability to speak, it's changes in your ability, in your cognitive function, and it is generally something that requires more severe treatment. So if you have heat exhaustion, you can generally treat that at home with hydration. One of the things that the mayor was mentioning earlier is that water is life. That's very important. If you're having a heat stroke, that should be, you know, you should be looking out for some of those more severe symptoms. And that should be a good reason to visit an emergency room or an urgent care facility to get your core body temperature cooled down.

20:27Jeeva, there are as many as 12 ,000 recorded heat deaths in the U.S. each year. How do we account for that? How do we know that people have died because of extreme heat? It's a complicated question. There's about three different ways you can calculate heat deaths. One is direct and indirect. These are two different categories of looking at deaths. So direct deaths from heat. There's a diagnostic code. It's X30. It's a medical classification for a death due to excessive natural heat. This is distinct from excessive unnatural heat, such as a tanning bed death, a bit of morbid trivia. But direct deaths are exactly what we're talking about in terms of heat exhaustion or heat stroke.

21:09The classic, what you think of as somebody dying from heat. Then there are excess deaths or indirect deaths from heat. That's cardiovascular events, stroke, complications from diabetes, respiratory illness, all the other ways that heat can kill you that may be a little bit more invisible. So if somebody comes into a hospital with a heart attack, the physicians are treating that heart attack. They're not sitting there being like, is this heart attack from the heat outside right now? So it might not be coded as a direct heat death, but it's still somebody who died from the heat. And there's two different ways you can count these excess heat deaths.

21:43So one is to look at how many more people died compared to what you would have expected for that period of time. um and so for an example of this is um in france there were uh 21 600 all-cause deaths between june 17th and july 2nd that was their heat wave in europe um statistical modeling would have expected about 15 910 deaths based on the previous year so that gives us an excess of about seven or 5 700 and then the third way of doing this is basically a predictive model so saying we know when the temperature rises by X amount, this number of people will die, and kind of using that model to fit with the temperatures that were recorded.

22:24So there's a bunch of different ways to record exos deaths, a bunch of different models that need to be peer-reviewed. And so this work is still ongoing for heat events, both in Europe and in North America. But this is why you can see many different numbers for how many people died in a given heat wave. We're getting texts and emails from you all. We got this text from one of you. I am medically unable to deal well with heat. Anytime the temps start hitting the upper 80s, I am strictly inside or headed for another air conditioned space. Of course, that means I miss out on all the nice outdoor activities, including the beach.

22:59Amrita, can I ask you, we also got this text. Is there any data on how COVID is impacting people's heat tolerances or exacerbating heat effects? I've been getting more frequent migraines from the heat. Friends of mine with high blood pressure are reporting suffering. It seems like I'm less able to tolerate it now than I was a couple of years ago. Yeah, that's a great question. And I think that there are potentially two things that are happening here. The first one is that obviously COVID changed a lot of people's ability to be in public spaces. And I think for a long time, people were kind of isolating and staying indoors, avoiding close contact with other people.

23:41And as a result, I think there have been some long-term impacts on immune systems across the board. And so I think people have definitely suffered from that long lack of exposure to the outdoors and to other people. And I think that has some immunological implications for the long term. I think the other thing is that people who have experienced COVID illness, and at this point we've gone through multiple waves of COVID, that might also have an individual level impact, as this person mentioned in their note. So people who have experienced maybe some of the symptoms of long COVID, we do talk about often how one of the most vulnerable groups to extreme heat is people with pre-existing medical conditions.

24:26So we do know that people who have underlying, for example, cardiovascular diseases or illnesses, people who have respiratory illnesses, people who have pre-existing mental health conditions may be particularly susceptible when it's very hot outside. And I would say the same is likely true for people who are experiencing the symptoms of long COVID. There might be some individual level vulnerability because of the long-term medical impacts that you're facing after having a period of COVID infection as well. I wanted to, Jeeva, talk to you about wildfire smoke. This year, along with the heat, we've seen wildfire smoke from Canada blanketing the Midwest and East Coast, affecting 115 million Americans.

25:08What's the relationship between extreme heat and wildfires? What's made this year's wildfire smoke especially bad? Yeah, so there's a lot of relationships between wildfire smoke and heat. In particular, this year, the smoke was directed over the most populated areas of the United States by the heat dome, which was raising all of those temperatures. So the temperatures got really hot in northern Minnesota and Ontario. There were lightning fires and that smoke then rotated around this heat dome that was making extreme temperatures and blew the smoke into some of the most populated areas of the country.

25:47and this is um when we talk about like compounding climate crises this is kind of the classic example of you want to run your air conditioning you want to have your windows open because it's so hot out but at the same time you need to protect yourself from the wildfire smoke um so these two crises really go hand in hand and make a kind of a perfect storm of like terrible conditions that you want to avoid. Yeah, Amrita, a study published in February by the journal Scientific Advance shows that wildfire smoke inhalation caused 24 ,000 deaths each year from 2006 to 2020. What effect does wildfire smoke have on our bodies?