How Hot is Too Hot?

Introduction to the episode

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The rising temperature of our world

1:36Let's take the temperature of our warming world. Cities are sizzling, polar ice caps are melting faster, and vegetation is withering on baked farmlands. Weather reports now routinely refer to heat domes and use words like freakish to describe record-breaking temperatures. We've known that climate change brings hotter temperatures,

2:06but to hear that heat itself is a major killer has caught many of us off guard. One of the things that makes heat different than other weather-related extreme events is that it's invisible, and we go out into it, and you can get into trouble very, very quickly. Our bodies evolved with thermoregulation to keep us cool, but they can't respond effectively to this kind of roasting. What does life on a scorched planet look like? And can we get smart about heat and engineer our way to a cooler future?

2:37This is Big Picture Science. I'm Molly Bentley. We'll look at the toll our inflamed world is taking on ice and oceans and how it's rewriting the geography of disease, plus what we can do to bring the temperature down. This episode is How Hot is Too Hot. I've stopped saying it's not the heat, it's the humidity, because the summer of 2023 demonstrated that, nope, it is the heat.

3:11My co-host Seth Shostak is on travel. Joining us to put the new heat in context is science reporter Gordy Slack, who has written extensively about climate change. Hi, Gordy. Hey, Molly. As you said, I've covered climate change for a long time, and rising temperatures are something I think about all the time. But the lethality of heat has really caught a lot of us by surprise, including an author who's covered climate change for two decades. Then he drove through Phoenix on a day when the temperature reached 115 degrees.

3:42Jeff Goodell is a Guggenheim fellow and a senior fellow at the Atlantic Council. A few years ago, we spoke to him about his book, The Water Will Come, that outlines a dire, wetter future, where increased flooding and rising sea level drown coastlines and cities. That interview was haunting. His description of Miami underwater was just so vivid and so scary. Absolutely, it was. And when we did speak with him, again, just a few years ago, rising water seemed like the single most immediate threat posed by climate change.

4:12We weren't thinking yet about heat as a physical force. That's right. We know that heat melts landlocked ice, which contributes to sea level rise, of course. But at that time, we didn't take to heart the toll scorching temperatures take on every other living thing. But now, one story after the next documents a world on fire. Heat records are being smashed not only from one decade to the next, but from one day to the next. Temperatures are so high that it's hard to wrap our heads around them. I've experienced 108 degrees in Arizona, but not that 115 degrees that hit Phoenix,

4:48or the almost unbelievable 134 degree heat index in Kansas. I mean, that's just incredible. And this heat has dire consequences. In a single district in northern India, for example, nearly 100 people died when a heat wave descended in June 2023. The heat will kill you first. Life and Death on a Scorched Planet is Mr. Goodell's compelling new book. He writes that because heat descends quietly, doesn't arrive with the racket of wind or the force of rushing water, a heat event can go unnoticed until it's too late.

5:21There's a lot to say about what heat does to living organisms and why installing more air conditioning is not a long-term fix because more AC means more global warming, and it's a vicious cycle.

What 115 degrees feels like

5:31But Mr. Goodell begins with a description of what 115 degrees feels like. I was staying downtown, and I opened the door from the hotel that I was in, and I walked out into what felt like just a wall of heat. And it was shocking, and it felt solid, and it felt alive, and it felt immediately oppressive. And I had about 15 blocks to walk to get to my meeting, and by the time I got to, I completed those 15 blocks,

6:01my heart was pounding. I was feeling lightheaded. And I realized that if I had to go another 15 or 20 blocks, I could be in real trouble. And it was right then that I decided that most people don't understand how dangerous heat is, and more or less then that I decided to write this book. But it was actually the feeling of 115 degrees, the actual feeling of trying to exist at a level of temperature that is beyond what we humans have evolved to deal with.

6:35You said that the heat felt alive. Can you elaborate on that? Yeah, I mean, it felt like it was, you know, this active presence, that it felt like it was something that my entire body was reacting to in ways that I didn't understand, and which is, I now know to be true, that extreme heat activates our sort of body's cooling system. It doesn't require kind of conscious awareness. We don't tell our brains that it's hot,

7:08and so we should cool down. Our body manages that on its own. It's one of the, you know, very basic kind of almost reptilian functions of our brain is to regulate our metabolism and our body temperatures. But, you know, it felt alive because it felt so predatory. It felt like, you know, I immediately felt vulnerable. It felt like this thing that was surrounding me and that was dangerous. And for me, I connected that with a kind of aliveness.

7:39And you write that heat is unlike other natural disasters because it arrives quietly, and you may not realize that you're in trouble before it's too late. Can you talk about how it operates almost by stealth? Yeah, I mean, so one of the things that makes heat different than other weather-related extreme events is that it's invisible. I mean, everyone knows that. But when you think about that, you immediately kind of begin to understand why it's so dangerous and why it's so problematic

8:11and maybe why we don't know that much about it, or many people don't understand the risks very well. You know, if a hurricane is coming and the wind outside is blowing at 75 miles an hour, you know it because the trees are bent in half and you walk outside and you can't stand up, and it's very clear, you know, visually and you can feel that this wind is, you know, dangerous. Heat is very different. I'm looking, I'm in Austin, Texas right now. I'm looking out my window in my office. I can't tell if it's 75 degrees or 125 degrees looking out my window.

8:45I'm lucky to be in an air-conditioned room. I have no sense of that. And so that changes how we register, you know, the risks and dangers of heat. And we go out into it and we often think, oh, this is not so bad. And, you know, you're fine for a little while. And then you begin to feel your body kind of trying to cool off and react into it in the way that it did on my short walk in Phoenix. And from there, you can get into trouble very, very quickly. And, you know, nobody stands on the beach in Miami and dies because of sea level rise, right?

9:20Sea level rise is a giant threat to coastal cities around the world and has enormous economic and other implications. But it's not a mortality event, per se. Heat kills you fast. My book is full of stories of people who, you know, die within hours of being exposed to extreme heat.

The hidden lethality of heat

9:40So it's very different that way. Well, one of the stories you tell is that of the family who recently died from heat stroke while hiking in California. And at the time, it wasn't clear what happened. I remember this. There were many theories. And I was one of the ones who thought that they had been poisoned by the toxic algae bloom in the river. Because, Jeff, living in California, having hiked in the heat, I wasn't thinking that heat was a killer. You bring some water, you pace yourselves. It wasn't one of the suspects. What happened to the family?

10:12This was a family, a man named Richard Garrish and his wife, Ellen Chung, and their daughter, one-and-a-half-year-old daughter and their dog. And Richard had been warned the night before by his brother, who is an experienced outdoorsman, that it was going to be hot the next day. And Richard said, yes, we know. We know. We're going to start early. We'll be okay. And it was only a seven-mile hike, about a mile from their house in Mariposa. They went down a trail to the Merced River, got down there around 10.30, had a nice time, no problems.

10:43And then around 11 o'clock, they headed up back to their car. It was about two-and-a-half miles. But it was two-and-a-half miles up a very steep switchback trail on a southern-facing slope with no shade. And they had not enough water with them, and they were out of cell phone range, so they couldn't call for help. And no one knows exactly what happened on the trail in detail. I speculate a little bit about it in the book. But basically what happened was the next day, friends were concerned they didn't return,

11:17and they were found dead, all of them, including the dog, on the trail. And as you pointed out, there were a lot of other ideas about what this might have been. But after several weeks of investigation, it turned out that it was heat stroke for all of the entire family. And I use it in my book because it's an example of how quickly heat can kill you and how it can kill you, even people who are in good shape, who are youngish,

11:48if you're in the wrong circumstances and you can't get out of it, you die. You say that they did not have enough water, but you also point out that it's a mistaken belief that if you drink enough water, that's sufficient to protect you from the heat. Why is it not sufficient? That's one of the great myths about our understanding about heat risk that I try to explode a little bit in this book. There's this notion that whatever the temperature is, I'll be fine if I just have enough water. And this idea that somehow water works as some kind of cooling mechanism,

12:19that it actually, when you drink water, you're cooling yourself off. But that's just simply not true. Water is really important to have with you because the only way that you cool off, other than getting out of the heat, the only mechanism we have to cool off is sweat. And sweat requires water, as we all know. However, it's very common to get into situations where it's hotter than even with a fully hydrated body, then you can dissipate the heat by sweating.

12:51So, for example, people who fight wildfires and are working in very hot conditions, working hard, they're wearing heavy equipment. There's many studies of them having heat strokes, despite the fact that they have access to gallons of water and as much water as they can possibly drink. What is it that heat does to our bodies? And you describe this in detail. Can you take us through the steps of what hyperthermia is like? And I should say that when I wrote the term hyperthermia into my notes,

13:22my computer wanted to do an autocorrect to hypothermia, which gives us an idea of perhaps how inadequately we are prepared to consider heat a threat. But what happens when you get hyperthermia and what kills you in the end?

How hyperthermia affects the body

13:38So what happens when you're exposed to extreme heat to your body is pretty straightforward. When you go into an environment that is hot, your body begins this process of your heart starts beating faster and your body starts pushing the blood in your body from the internal organs and other places to just below the surface of your skin. So that as you sweat, that sweat dissipates, carries away the heat and cools the blood off just below the skin.

14:09That cooler blood is then recirculated through your body and that is how you cool down. That's how you keep your inner body temperature within the range of survivability. And that's a very important mechanism. Humans are very unique in their ability to sweat, especially while in motion. And it's given us many evolutionary advantages and it works really well within range. But if you continue to be exposed into hot weather and your body cannot dissipate the heat fast

14:40enough through sweat, your heart starts beating faster and faster and it pulls more and more blood away from your internal organs and importantly, your brain. If your body temperature then is raising up to 102, 103 degrees, your heart starts really kind of pounding ferociously, desperately to get as much blood as possible towards your skin. And often this is the place where people who have any kind of circulatory problems or they have any kind of heart problems immediately get into trouble and in some cases die of a heart attack

15:13right there because it puts tremendous strain on your heart as your heart basically panics, trying to push enough blood out to the surfaces of your skin to cool off. But if you're, if you have a strong heart and you continue on as the temperature rises, what starts to happen is that your actual, the cell membranes in your body begin to, what scientists call denature, basically melt. Your kidneys, the cells in your kidneys are among the first to go. They're very strained by having to process the fluids, the water that you're circulating

15:47through as you're drinking and sweating. It's one of the first organs that gets in trouble. And as your temperature reaches 104 degrees, 105 degrees, 106 degrees, you literally start melting from within. And this is important not just because it sort of sounds like a horror story, which of course it is, but it's also important because the only treatment when you're in these kinds of conditions is to get your body temperature down. So for example, during the Pacific Northwest heat wave in 2021, emergency rooms would fill body

16:19bags full of ice and zip people into ice filled body bags.

16:24And, but there's also this sort of melting process that happens, this denaturing process. You can still have a lot of permanent damage to your body because your body has started to kind of fall apart from inside. And so exposure to extreme heat can be very damaging in the longterm, even if it doesn't kill you. That was gripping. And it is, does sound like a horror story. I wonder if you could put in perspective for us why it is that we, many people, not all people around the world, of course, have been so ignorant about the dangers of heat.

16:57We've known for decades now that our planet has been warming up. I mean, since the NASA scientist James Hansen presented the facts before Congress in 1988, the concept of global warming, the concept of climate change is not new to us. Why is the message of heat as a threat to life on the planet? Why does it feel like a new message? Well, part of it has to do with, I think, the events of this summer, which was particularly extreme, not just in the United States, but throughout the world, because of the warming

17:30that we've created in the atmosphere due to the burning of fossil fuels. It has driven the sort of average temperature of the planet up by more than a degree or so, which has created a kind of higher base level of temperature. And then we've had, you know, this has been an El Nino year. So that's a kind of seven-year planetary atmospheric oscillation pattern that changes the flow of heat through the atmosphere and generally leads to hotter weather, hotter summers

18:05in the Northern Hemisphere, especially. So those two things overlaid together created this really brutal summer this year that really exposed, you know, tens of millions of people just in the United States. I mean, at certain points in the summer, there were more than 100 million people under extreme heat warnings to the dangers of this. And they, I think a lot of people had experiences like the one that I had that I described earlier in Phoenix, where I went out and naively thought that I could, you know, take a 15 block walk in 115 degree temperature and realize all of a sudden it was dangerous.

18:38And so I think that these extreme temperatures have woken up a lot of people to this. Um, many people have commented this summer, this was the hottest summer on record and also the coolest summer that, you know, you're going to experience for the rest of your life. You know, it's going to continue to get hotter and hotter and hotter.

19:00Wow, Molly. Heat is a really big deal. I mean, I'm surprised by how vulnerable the human body is to just a few degrees in heat difference. You know, he gives that vivid description of our cells almost melting under the heat. Yeah, that our bodies begin to disintegrate. Is it a surprise to you as someone who's covered climate change to learn that heat can have a direct assault on the body in this way? Very surprising. Yeah. Why? Why? You've covered climate change for a long time. Well, I think I've paid a lot of attention to the rising temperature of our climate, but

19:36not so much the rising temperature of our weather. I don't think of it as so much an acute problem as a problem for populations and for habitats, but not so much for individuals exposed to extreme heat. Have you ever had heat stroke or have you been in a situation where you thought you had overexposed yourself to extreme temperature? Well, yes and no. So I had heat stroke, but I didn't think that I had overexposed myself. I had a heat stroke when I was sailing as a kid and I'd just been sailing all morning and out in the sun and then I started to throw up and to get dizzy and it turned out I had

20:11heat stroke. I didn't even know I was hot.

Impacts on animals and ecosystems

20:24Other living things are hit hard by rising temperatures too. Find out how desert ants are trying to outrun the heat, how heat changes the metabolism of plants, and the shifting geography of disease-carrying mosquitoes. It's How Hot is Too Hot on Big Picture Science. At Edward Jones, we believe rich is more than caring about the latest and greatest.

20:56It's also taking care of what gives your life meaning. That's why your dedicated financial advisor meets you where you are with personalized financial strategies that help protect what matters. so you can preserve your progress while creating a path forward. The key to being rich is knowing what counts. Let's find your rich together. Edward Jones, member SIPC.

21:29We share this planet with countless other magnificent forms of life. Hotter temperatures put them under siege too, from ants to oak trees. How they are responding is one of the many consequences of a hotter planet that Jeff Goodell describes in his book, The Heat Will Kill You First, Life and Death on a Scorched Planet. Your previous book, The Water Will Come, made a strong impression on me as well. And when you wrote it, and when we spoke to you, it sounded like you thought that the water would get to us first.

22:01And now it sounds like heat has become the predominant force. And I'm wondering how you think about the two threats now, because of course, they're also linked, aren't they? Rising temperatures and rising water. Yeah. So in this book, I talk about heat in two ways. The reason the book is called The Heat Will Kill You First is because I wanted to talk about heat as, as we talked about earlier, as an active force. That's something that is here now and that can kill you now, just as it killed this family

22:32on the hike. It is a real and present danger in our world right now that we need to understand better and get smarter about. But I also wrote about it as a kind of planetary force, you know, this rising temperature on our planet is what's driving all of these other climate events, including the melting of glaciers. You mentioned that my last book was about, was about sea level rise. And that is driven by the warming planet that is melting the ice sheets and causing seas to

23:07rise and will continue to cause seas to rise as long as this warming continues. And they're both, you know, extreme heat and sea level rise are two different aspects of this larger thing we call the climate crisis. And they're very, you could say on one level, they're, they're driven by the same, obviously they're driven by the same thing, which is the, you know, rising temperatures on the planet related to fossil fuel burning. But as I kind of hinted at a little bit earlier, sea level rise is a very different kind of

23:41threat and kind of danger. It's not a threat to human life in a immediate kind of way. It, yes, it makes storm surges bigger. But what it's really doing is, you know, changing the boundary between land and sea and flooding cities, causing enormous property and infrastructure damage. And it's going to remap our world. And it's really, really an important aspect of thinking about what our future is going to look like.

24:11But heat's very different. Heat is a thing that kills humans, kills living things. It's a threat to mortality. It's not really a threat to property. It's not a threat to how, to the sort of existence of cities per se. It's, it is a threat to our lives and to the lives of all living things. Well, let's talk about some of those other living creatures and the planet itself, because we have a long history with heat. Life evolved on a planet in the Goldilocks zone. And in that way, the distance from our sun, the amount of heat that we receive on this planet,

24:46heat was our friend. Heat is what allowed life, heat and water to take off on this planet. Right. And, you know, I talk about, you know, the Goldilocks zone in the book. And the Goldilocks zone is not a term that I invented. It's a term that, you know, planetary scientists use when they're looking for life on other planets. And they use it to describe the presence of liquid water, which they see as a precursor to any form of life. So the Goldilocks zone, you know, if it's, if it's too cold, the water is ice and they

25:17presume nothing, there'll be no life on the planet. If it's too hot and there's no liquid water and it's all vaporized and they presume it's too hot for any form of life. And that same, you know, idea connects with our moment and our history here on Earth. You know, we evolved in this relatively stable climate with this relatively stable range of temperatures that our bodies can handle and the bodies of other living things can handle. We have all found our ecological niches, whether it's the redwoods, you know, on the coast of

25:52California or the Great Barrier Reef in Australia or the termites in Botswana. We've all thrived in these particular niches that have allowed us to live and to evolve. We're very well suited to those ranges of temperatures. The problems begin when, when the temperatures go out of those ranges. And that's what, in brief, what the climate crisis is doing is, is pushing us out of our Goldilocks zone. Let's look at some of the animals specifically. Now, there are some animals that really do thrive, or at least they survive in desert heat.

26:27And you write about, I believe it's this silver Saharan ant. And the image of this ant running is really stuck in my mind. Can you just tell us how this ant manages to survive these baking temperatures in the desert? Yes, I became very interested in, in creatures, animals that can survive in extreme conditions, such as inside the, you know, the really, really hot springs at Yellowstone and places like that. And the silver Saharan ants that thrive in these really extreme temperatures of 140,

27:00150 degrees surface temperatures in the desert, are great examples of that. They're incredibly well evolved to deal with these extreme temperatures. They are, first of all, silver. So they reflect away light and heat in the same way that a white roof or a white t-shirt makes you cooler than a black t-shirt. They're, they're a light color. They have an ability to run very quickly. And, um, they kind of gallop so that their feet are not on this, the really hot sand for

27:30very long. Unlike other ants, they have a completely different gait and they've specialized in going out in extreme heat and preying on, um, other insects that have died in this heat. So their whole sort of, um, survival is dependent upon the death of other creatures in these hot conditions and they go out and scavenge the bodies of other insects and other animals that have died and drag these carcasses and other things back into their, their cool colonies and eat them.

28:04And they're, they're a great example of how life, given enough time, can adapt to really extreme circumstances. And there's a certain kind of beauty and poetry in that. Not all animals, of course, are adapted to these hot temperatures. And you report on some of the migratory patterns that are happening now among terrestrial animals. They're moving to colder climates. And I think there is a common misunderstanding about this, that people will say, well, okay,

28:37well, so if it's getting warmer, species will just move by adapting. They'll just go to more northern climes. So we'll have the same species. They'll just be at different latitudes. Animals and humans have always adapted to changing environments, but there's a fundamental misunderstanding about that. Yeah, there's a fundamental misunderstanding, which is, first of all, that many animals and living things can't move. You know, if you're a redwood tree, it's not easy to just like uproot yourself and trot up to Canada where it's cooler, right? That doesn't work so well. If you're coral, you know, you're part of a colony in a coral reef.

29:11You can't just like float up to somewhere else and, you know, you're stuck there and you're not mobile. And so there's a lot of living things that cannot migrate, first of all. They just, or they don't have space to migrate to. The last chapter of my book is about an encounter I had with a polar bear on Baffin Island, which is in the Arctic Circle. And, you know, there's no cooler place for a polar bear to migrate to, right? So this whole notion of migration, first of all, depends on mobility and having a cooler

29:44spot to go to. And for a lot of creatures, including plant life and animal life, you know, it's just not a simple narrative where some creatures are very good at it. Birds, bats are very mobile and can easily move to new places. Since I've published this book, I've heard endless stories about sharks appearing in new places, more northerly places because of the cooler waters. And they're seeking out these, you know, more comfortable ocean zones for themselves.

30:18And of course, terrifying people who are used to swimming in shark-free waters. And all of a sudden, a great white shows up. It caught me by surprise that one of the most vivid descriptions in your book was the one that you gave to the 150-year-old oak tree in Melbourne that you described lying on its side like a fallen idol. And what was so sad about this is that the oak tree that had withstood a century and a

30:48half collapsed under the heat. I mean, collapsing is something that humans do, you know, that animals do. But you don't expect trees to collapse under the heat. What had happened to this tree?

31:04Well, you know, this tree, first of all, no one knows the exact sequence of events that caused this tree to collapse. It had to do with age. It had to do with drought. It had to do with extreme heat. It had to do with, you know, one of the things that these changes in temperatures do that impacts things like this oak tree and has a big impact in the United States and in the Rocky Mountains and other forests is accelerates the life cycles and range of insects that are, you know,

31:39that prey on them. So pine bark beetles are a great example of this in the United States, but especially in the Rocky Mountains, where huge swaths of forests have been decimated by pine bark beetles, which love the heat and thrive. And their metabolism is actually accelerated by the heat. So they become ever more active. And then one of the other fascinating things that I learned in my reporting about heat and drought's impact, and heat and drought are, of course, linked, impacts on trees especially,

32:12is that there are some scientists who have developed microphones that can listen to essentially the veins in trees that carries water up and down the trees and are essential to their lives, they can actually hear what they describe as the trees screaming as these veins and capillaries in the tree crack and break under this extreme stress. I find the complexity of these kinds of responses from trees and plants to be completely fascinating.

32:47We talked about the silver Saharan ant before. There's so much we don't understand about how heat impacts other living things. And I think, you know, the story of this oak tree was a great example of that. You write that heat rearranges the natural world.

Pathogens and ticks on the move

33:02And one of my favorite quotes in your book about rising temperatures is that they are turning pathogens into microscopic versions of Ferdinand Magellan, expanding boundaries of the known world. And that would be kind of exciting, Jeff, if it weren't so terrifying. So what's happening is that diseases that are passed by, say, ticks and mosquitoes, for example, that were endemic to one part of the world are now moving to other parts of the world. What's happening?

33:32Well, you know, like mosquitoes and ticks are great examples of this. You know, they're just like every other creature from, you know, as I mentioned before, from humans to redwoods to polar bears who, you know, when the temperature changes, they seek out new environments that is more comfortable for them. And as it gets hotter, their range expands and they're very mobile. And when they move, when they travel, they carry things with them. They carry, in mosquitoes case, you know, things like dengue fever and Zika and malaria.

34:07Which still kills 400,000 people or so in sub-Saharan Africa every year. And the range of these malaria-carrying mosquitoes are expanding and exposing new populations to these mosquitoes and to these diseases that have never had to deal with it before. I mean, here in the United States, in the last couple of months, there's been a number of new, of cases of malaria in the Southeast. And it's a disease that was wiped out here for decades.

34:40That no one, there was no cases of malaria. And now it's resurging. And one of the reasons it's resurging is because the mosquitoes that carry it have found new range and are moving into new terrain. They're the Ferdinand Magellans that you mentioned in the beginning of your question. If we can talk about ticks for a moment, because in some ways, they're appearing as the new vectors of disease. We're familiar with mosquitoes. Mosquitoes and what they can carry are very scary. But ticks now are extending their range.

35:12And they're really good at moving, you write, but also resisting the heat. Because I guess they don't need a lot of water. Now, our family is familiar with Lyme and babesiosis. We've had members of our family have both. But you mentioned other diseases that are appearing on the East Coast that I wasn't familiar with. I wonder if you could talk a little bit about how heat is changing the ticks appetite in particular, and the kind of new diseases these animals are bringing. So, I mean, ticks are very, I lived on the East Coast for a long time.

35:45I'm very familiar with, you know, the concerns about ticks and the trajectory of Lyme disease, you know, starting out on, you know, basically in Long Island and Connecticut region and moving all the way up now to the Canadian border. And that is completely a consequence of warming. Ticks are particularly good at moving with temperature changes. You know, they're particularly resilient to drought. They can bury under the ground and sort of survive for a long time.

36:19They're very difficult to track. They're very difficult to study. As someone who has done regular tick checks on my family, they're tough to spot sometimes. They are. And there's, you know, new species of ticks that carry new kinds of diseases. So we're very, most people in the United States are aware of Lyme disease and the risks and dangers of that. But in my book, I went to a national lab in Galveston, Texas, which is one of the epicenters of the studies of ticks and new diseases. And the scientists that I spoke with down there was talking about a disease called Crimean-Congo

36:55hemorrhagic fever, which is a really terrifying disease. Well, if it's hemorrhagic fever, it's in the family of fevers that includes Ebola. Right. And it's, you know, similar to that in that it causes, it injects an anti kind of coagulant into your bloodstream that causes massive bleeding. And, you know, mortality is, depending on how you calculate it, you know, 30, 40, 50 percent of people who get this die.

37:25There still hasn't been any presence of it in the United States yet, but it's spreading in Europe and they're seeing more and more evidence of it. And, you know, I don't want to like overstate it. You know, it's one of these things that is completely terrifying to think about having a disease like that injected into our world, especially in something like ticks, which are so, so kind of terrifying in their own way and so difficult to deal with.

37:57But this is really the kinds of risks that we're talking about as we heat up our planet. We are, you know, causing this sort of great rearrangement where creatures are finding new places to live. And a lot of those creatures are bringing things with them that we don't want to be around. And that's a great example of it.

38:21So, Molly, thinking of ourselves as people who get hot, that is something that we're used to. Extraordinarily hot, maybe not so much. But thinking of other animals and plants as overheating isn't something we really think that much about. And the profound assault that these extreme heat events will have on populations of plants and animals is just something it looks like we haven't really calculated. We don't know how to prepare for or to think about.

38:53And it's heartbreaking. There's something just very beautiful about how life evolved in the Goldilocks zone at a certain temperature range and that everything is exquisitely tuned to that temperature. And we are just blowing through it. You know, we have this planet. It's perfect for life. It's the only planet we know where there's life on it. And what we fear is that we've been taking that for granted, that temperature zone. Yeah. And the temperature, as you said, it's a zone.

39:25It's not a particular temperature. And it's changed over time. And it will continue to change. But it changes historically. It's changed very, very slowly. And what we're experiencing now is the zone moving way beyond our own comfort zone. And it's already proving catastrophic. Well, as they say, despite that everybody's always talking about it, we can't do much about

39:59the weather. But we can tackle the problem of a warming planet. It is not too late. It's not even close to too late. There's a lot we can do that can change the trajectory of all of this. Next, find out why turning up the A.C. or moving north are not long-term solutions, but what might be. This episode is How Hot is Too Hot on Big Picture Science.

40:31Your heart can tell you a lot about your health. Apple Watch Series 12 measures your heart rate every five seconds with the most accurate heart rate sensing in a wearable. So your vitals app, now with heart rate variability, can tell you when something is off. And your readiness score can let you know when to rest and when to push. Hear the story in every heartbeat with Apple Watch Series 12. The features described are for wellness purposes only and not for medical use. iPhone 11 or later required. Based on Apple conducted study of heart rate accuracy, August 2026. Visit apple.com slash Apple Watch Series 12.

The vicious cycle of air conditioning

41:09We started this episode with stories about how hotter temperatures are affecting nearly every inch of this planet. There's just so much at stake. And if you've been listening to this while sweating under sweltering temperatures, I hope you stay hydrated. But as Jeff Goodell said, it's not enough to drink a lot of water. Sometimes you have to get out of the heat altogether. And many of you are keeping cool heads by cranking up the AC. And that cool air definitely brings relief. But growing dependence on air conditioning contributes to vicious cycles that imperil our

41:40planet in other ways. Author Jeff Goodell describes sustainable, effective responses to our new heat and what it will look like if we don't do anything, but instead continue to push our planet beyond its Goldilocks zone. Well, Jeff, I wonder if you could help us out here then, because this is all very scary. I mean, the stories are getting scarier as we go on. This is reality. These are the facts we need to face.

42:07How do we solve this problem?

Engineering solutions for hot cities

42:10Do we engineer our way out of it? I mean, what is to be done? I know that's a big question, but we need to hear what we can do. Or is it too late? No, it's certainly not too late. I mean, I, you know, my book is full of horror stories and full of scary things, but it is not a doomer book in the least. It is alarming and it should be alarming. And people are not alarmed enough about what's happening in our world. But it is not too late.

42:40It's not even close to too late. There's a lot we can do that can change the trajectory of all of this. I am a big believer in the reason I've been able to write about climate change for the last 25 years now is because of all of the people that I've met who are so actively engaged in solving these problems and trying to build a better world and all these incredible creative solutions. To me, it's a very inspiring in its own kind of strange way, kind of beat to be covering as a writer.

43:11But to point to things that we can do specifically about heat, number one is like, get smart about it. Understand what the risk is. You know, whether you read by reading my book or reading somebody else's book or talking to public health officials or Googling or whatever it is your method of education is, most heat deaths can be prevented. If people understand the risks, if they check in on their neighbors and loved ones who might

43:42be at risk, if we could pass laws, for example, that require water and shade breaks for outdoor workers, you know, there's a lot of very simple things that we can do to keep people from dying of extreme heat. We should interject, as you point out, that air conditioning is not the solution everywhere. Of course, air conditioning has made living in places where you are right now, living in deserts, possible. You know, you shouldn't actually be sitting there in Austin, Texas, talking to me, and

44:15you wouldn't be if we didn't have air conditioning. And that goes for many places around the world. But not everybody has air conditioning. And yet you write about how we are addicted to it. I wonder if you could just speak to how air conditioning is not the solution. And in fact, sometimes it can get us into a vicious cycle. So air conditioning, you know, one of my fears in writing this book, and one of the things that I wanted to dispel is this notion that air conditioning is sort of a magic fix for extreme

44:46heat, that we don't need to worry about a hotter planet because we've got air conditioning. And all we got to do is get more air conditioning to more people and everything will be fine. And that's the solution. And so why are you spending your time writing a book about it and worrying about it? Well, there's a lot of problems with that, starting with the fact that there are billions of literally billions of people on the planet right now who do not have air conditioning. And for all intents and purposes, we'll never have air conditioning. Not just, you know, in faraway places in the Middle East or in sub-Saharan Africa, but, you know,

45:21here in Austin, Texas, three blocks from where I live, in Phoenix, where I spent a lot of time reporting this book, in New Orleans, in all kinds of really hot places in our world, there are people who are living without air conditioning because they can't afford to have air conditioning, or they're living in structures that don't allow air conditioning, or they're outdoor workers who are outdoors. You know, there's some guys right now down my street who are putting in a new water main and are working out in the middle of the day in Texas, you know, on black, hot black

45:52asphalt. They don't have air conditioning and they're never going to have air conditioning. I wrote about an agricultural worker in my book who died in the fields working. Agricultural workers are not going to have air conditioning. So air conditioning is part of this line in my book that I talk about between the cooled and the dammed. And, you know, one of the things that heat is doing is bringing up all these justice and equity questions. So the notion, then beyond that, the notion that we're, you know, going to air condition, we're not going to air condition the oceans. We're not going to air condition the forests. And moreover, we're not going to air

46:26condition the wheat fields and corn fields that grow the food that we eat. So the consequences of rising temperatures to our food supply is something we really haven't even touched on. But again, is outside this air conditioning bubble. Part of my attempt in this book is to break out of that and to show that air conditioning is a comfort, but it is not a solution. Well, you talked about how individuals can get smart about the heat. Have you seen a case in which a city has gotten smart about the heat? And you write a lot about the role of planting trees,

46:59which I loved reading about. I'm sure it's not the whole solution, but trees seem to be playing a role in cooling off cities. What's one project that you found really encouraging? Well, there's a number. One, I would point to Paris. Paris has done an amazing job of trying to reintroduce nature, not just trees. Trees are a big part of it, but reintroduce nature back into the central city. They've done that by doing a number of things like, you know, restricting vehicle access

47:32cars into the inner city, cleaning up the Seine. The Seine is now, you know, clean enough to swim in, tearing up a lot of roads and planting trees and other greenery, really trying to reintroduce nature into the heart of an iconic city like Paris. I think that they're doing an amazing job of that. You know, cities, even, you know, heat stressed cities like Phoenix are working hard to create shade structures, different kinds of bus stops, for example, cooling centers where people can go who

48:09don't have air conditioning, can have access to cooling on hot days. I mean, even simple things like, you know, extending library hours and things like that so that people have places to go. I mean, a lot of this stuff is like not that hard, you know, and a lot of it has so many co-benefits, like, you know, the introducing greenery and nature back into cities and rethinking urban areas as not just asphalt and concrete, but as this sort of meeting point with nature. So I think there's a lot

48:39of reimagining of cities that is going on that I think is really inspiring and will make cities better places, you know, and I feel it very strongly here in Texas, where it's all these like 18 lane highways and asphalt and concrete everywhere. And that idea is changing, you know, we can't continue to live in a hotter and hotter world if we're going to continue to build cities this way. And I think there's a lot of inspiring change.

A more chaotic planetary future

49:09Well, Jeff, now that we've gone from positive, we want to end perhaps on a somber, more somber note, because your last chapter looks at where we're headed if we don't do anything. And it raises the question of what it looks like if we push the planet beyond the Goldilocks zone. And what would that look like?

49:31You know, it would look like a radically different place than the world that we live in now. And, you know, there is no kind of one Goldilocks zone that what will happen, and is already happening is certain niches for certain ecosystems will vanish. And, you know, it will, for example, places in northern India and Pakistan are already on the verge of being too hot for people to survive in who do not have, you know, full access to air conditioning, we're starting to see, you know, more and more crop

50:03failures. We're starting to see more and more species extinctions of species who cannot migrate to cooler places. And in my book, I talk about extreme heat as the engine of planetary chaos. And I think that that's the best and most accurate description that I can paint of a hotter world, of a world where we do not take seriously the urgency of cutting fossil fuel emissions and stopping this temperature rise. It's going to be a more chaotic world, more migration, more people moving across

50:38borders, more conflict as a result of that, more food shortages, more diseases breaking out in new places that we don't, that we don't expect. It's going to be a more chaotic, more dangerous world for millions of people. Well, Jeff, I hope the next time that we talk to you, it won't be about rising waters or extreme heat, but it'll be a review of all the wonderful solutions that humanity has come up with. Jeff Goodell, what a pleasure it is to speak with you. Thank you very much.

51:10Thank you for having me. It was a great conversation.

51:14Jeff Goodell is the author of The Heat Will Kill You First, Life and Death on a Scorched Planet. I'm really struck by how at the same time Jeff is so acutely aware of the dangers posed by extreme heat. He's also really hopeful about the future and about the human ability to awaken to this danger and to respond to it creatively and quickly and effectively. And I don't know if I could sustain that same hopefulness. One thing we didn't have a chance to get to was the vicious cycle that the use

51:48of air conditioning can put us in. Can you explain it? On the one hand, air conditioning protects people from the extreme heat. On the other hand, it contributes to the extreme heat by requiring more carbon emissions to generate the electricity for the air conditioning. Air conditioning makes it cool inside the house, but it also pumps hot air outside the house. So it creates hot zones in cities. It actually increases the temperature of cities. And it also makes people really vulnerable because when there are extreme heat

52:18events, air conditioning along with the rest of the power grid can go down, leaving people who thought they were safe extremely vulnerable and are sealed in homes become death traps.

Summary of climate reporting

52:30Well, Gordy, what is the big picture here? Are you willing to give a summary to what you heard as someone who has covered climate change for a long time, but also as a subject that has been covered for a long time? In this case, we focused specifically on the role of heat. What is the big picture in your mind? Yeah. Well, Molly, I think his expression that extreme heat is the engine of planetary chaos is one that I will bring home with me from this interview. And also the fact that

53:01although this was the hottest summer on record, it will probably be one of the coolest summers that we remember because it's just getting hotter and hotter. And we need to take to heart the threat that temperature poses along with the other effects of climate change, climate catastrophe, and that there is time to make a difference. And that time is now. Gordy Slack is a science reporter and a longtime climate reporter. Gordy, thank you so much for joining us on this episode.

53:33It was my pleasure, Molly. Thank you for having me.

53:37This show would not be possible without the hot talents and cool heads of senior producer Gary Niederhoff and assistant producers Brian Edwards and Shannon Rose Geary. A special thanks to science reporter Gordy Slack for joining us on this episode. I am the executive producer of Big Picture Science, Molly Bentley. Original music in the show by Dewey DeLay and June Miyake. This episode of Big Picture

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55:48Your heart can tell you a lot about your health. Apple Watch Series 12 measures your heart rate every five seconds with the most accurate heart rate sensing in a wearable. So your Vitals app, now with heart rate variability, can tell you when something is off. And your readiness score can let you know when to rest and when to push. Hear the story in every heartbeat with Apple Watch Series 12. The features described are for wellness purposes only and not for medical use. iPhone 11 or later required. Based on Apple conducted study of heart rate accuracy, August 2026. Visit apple.com slash Apple Watch Series 12.