How Your Refrigerator Changed Human History & The Surprising Purpose of Volcanoes -SYSK Choice

Most arguments seem to be about just one thing: money, chores, politics, parenting, work, or whatever sparked the disagreement. But according to experts in conflict resolution, there is often something deeper happening beneath the surface. In fact, many arguments become difficult to resolve because two separate problems are being confused as one. Understanding the difference can completely change the conversation. Source: Jim Ferrell author of The Anatomy of Peace (https://amzn.to/4erYLUP). Imagine grocery shopping every day because food spoiled almost immediately. Imagine no frozen food, no leftovers, no supermarkets stocked with fresh produce year-round, and no easy way to transport food across long distances. Just 150 years ago, that was normal life. Then refrigeration arrived and quietly transformed almost everything about how humans eat, live, work, and build cities. Yet this remarkable technology has also created unexpected consequences for our health, food systems, the environment, and even our relationship with nature. Nicola Twilley, writer, co-host of the popular Gastropod podcast (https://gastropod.com/category/podcasts/), and author of Frostbite: How Refrigeration Changed Our Food, Our Planet, and Ourselves (https://amzn.to/3VuXNP0), reveals the fascinating story behind one of the most important inventions in human history. Volcanoes are among the most destructive forces on Earth. They bury cities, disrupt climates, and unleash enormous power with little warning. Yet without volcanoes, life on Earth might never have evolved the way it did—and may not exist at all. Where does lava come from? Why do volcanoes erupt where they do? Why do some remain dormant for centuries before suddenly awakening? And what role have volcanoes played in shaping the planet we call home? Tamsin Mather, professor of Earth Sciences at the University of Oxford and author of Adventures in Volcanoland: What Volcanoes Tell Us About the World and Ourselves (https://amzn.to/3xk4DyI), explains why volcanoes are not just geological curiosities but one of the fundamental forces that made Earth what it is today. Most purses travel everywhere their owners do—restaurants, public restrooms, grocery stores, offices, airports, and countless other places. Along the way, they collect far more than receipts, lipstick, and keys. Researchers have found that purses can become surprisingly dirty, and what accumulates on them can be more than just kinda gross—it may pose a legitimate health concern. https://finderskeypurse.com/blogs/finderskeypurse-com-blog/how-dirty-is-your-purse-plus-how-to-keep-it-clean PLEASE SUPPORT OUR SPONSORS POCKET HOSE: For a limited time, when you purchase a new Pocket Hose Ballistic, you'll get a FREE 360 degree rotating pocket pivot and a FREE thumb drive nozzle! Just text SYSK to 64000 AIR DOCTOR: Head to ⁠https://AirDoctorPro.com⁠ and use promo code SYSK to get $250 off select AirDoctor air purifiers, including the 3500, 4000, and 5500 models. Plus, you’ll receive a free 3year warranty! RULA: Thousands of people are already using Rula to get affordable, high-quality therapy that’s actually covered by insurance. Visit ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠https://Rula.com/sysk⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ to get started. QUINCE: Elevate your summer wardrobe. Go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠https://Quince.com/sysk⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ for free shipping on your order and 365-day returns. Now available in Canada, too! DELL: With the Dell Pro laptop powered by Intel Core Ultra with vPro, no matter how many interruptions you have, your laptop won’t be one of them. With battery that’s optimized for the way you work, and built-in intelligence that quiets distractions the moment you’re trying to focus, your tech won’t slow you down. Find out more at ⁠⁠⁠⁠⁠https://Dell.com/Dell-Pro⁠⁠⁠⁠⁠ SHOPIFY: It's time to turn those "what ifs" into CHA CHING with Shopify Today! Sign up for your $1 per month trail and start selling today at ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠https://Shopify.com/sysk⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ Learn more about your ad choices. Visit megaphone.fm/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

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• 0:14Mike Carruthers?

  Today on Something You Should Know, how to stop an argument before things get out of hand. Then, refrigeration. It's revolutionized how we all eat, but it scared people in the beginning.

• 0:30Speaker 02

  People were seriously against it at first. They were afraid of it. People thought this was zombie food, undead, and they didn't trust it. And quite right, because they no longer knew how to know whether it was fresh or not.

• 0:46Mike Carruthers?

  Also, there's something in every woman's purse that probably needs attention. And volcanoes. You know what they are, but you may not know a lot about them. They're really fascinating.

• 0:57Speaker 03

  One of the things that fascinates me about volcanoes is we would not be here, I don't think, as a species if it was not for volcanoes. The gases coming out of volcanoes help to maintain our atmosphere over geological time.

• 1:10Mike Carruthers?

  All this today on Something You Should Know. Now here's something that might be worth a minute of your time. How would you like $1,000 to spend on shopping, especially with the holidays coming? Well, the people behind Shopify have a shopping site called shop.com. And to celebrate the new shop.com, they're giving away $1 million in Shop Cash. But not to one person. A thousand people will each win $1,000 in Shop Cash. And shop.com is actually a really clever idea. It brings lots of different stores together in one place.

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  So instead of bouncing around from website to website, you can search across stores, find what you're looking for, and track your orders all in one place. Clothes, electronics, gifts, things for the house, all kinds of stuff. And whether you win or not, it's worth knowing. But with a thousand chances to win $1,000, I'd certainly take a look. Enter to win the $1 million Shop Cash giveaway from now until November 1st. Just go to shop.com. There are so many ways to win. That's shop.com. Shopping designed around you. No purchase necessary. Restrictions apply. Official rules available at shop.com.

• 2:39Speaker 04

  Something you should know. Fascinating intel. The world's top experts. And practical advice you can use in your life today. Something you should know with Mike Carruthers.

• 2:53Mike Carruthers?

  Hi there. Welcome. I want to start this episode by offering up some really good advice that will make you better at resolving any conflict. And it comes from a gentleman named Jim Ferrell, who wrote a book called The Anatomy of Peace. You see, in any conflict, you've got a couple of things going on that make it difficult. Number one, no one in a conflict thinks they're wrong. So trying to convince someone they are wrong, while that may feel like the right thing to do, rarely moves the conversation towards a resolution. In fact, it often makes things worse.

• 3:32Mike Carruthers?

  Number two, the natural tendency in a conflict is to ask at some point, "So how do we fix this?" The problem with that question is that you're trying to fix something that has already gone wrong. It's already broken. That's not always possible or even desirable. A better question might be, "What can we do to help things go right?" That steers the conversation towards a more permanent solution. Understanding these two concepts and putting them into action can make anyone better at resolving conflict. And that is something you should know.

• 4:12Mike Carruthers?

  There is this invention, this technology that you interact with every day. You probably don't give it much thought, yet it has really changed the world significantly, more than you probably realize. And that invention is refrigeration, artificial cold. And yes, having a refrigerator in your kitchen is wonderful, but like with any technology, there are problems too. Here to help you understand how your refrigerator changed your life is Nicola Twilley. She is a writer, frequent contributor to The New Yorker, host of the podcast Gastropod, and author of the book Frostbite: How Refrigeration Changed Our Food, Our Planet, and Ourselves.

• 4:57Mike Carruthers?

  Hi Nicola, welcome to Something You Should Know.

• 5:00Speaker 02

  Thank you for having me.

• 5:01Mike Carruthers?

  So let's start with just a real quick history lesson here. When did refrigeration become a thing for people?

• 5:09Speaker 02

  Well, so humans have noticed that cold kept food good since humans noticed things. There are examples of Paleolithic people using ice pits to keep their mammoth fresh. The trick was, no one could make cold until really recently. And so, people didn't see cold as a very useful way to preserve food because natural cold was so unreliable and it's not available everywhere and it's only available in the winter, so you just didn't rely on it. You used it. People used ice to make ice cream in summer or to make wine slushies. It was a treat, but they didn't rely on it for, you know, shipping meat across the country.

• 5:52Speaker 02

  When a scientist, a guy at the University of Edinburgh, first figured out how to make artificial cold, it was seen as a party trick. No one knew what to do with it. And it's actually really, really, very recent, 150 years only, that we've actually sort of used cold commercially to ship food around the world.

• 6:18Mike Carruthers?

  Isn't that amazing, that it's only 150 years old and yet it is just part of everybody's life every day in this country? And what about freezing? Are refrigeration and freezing all part of the same development of technology? Or are they two parallel paths of two different things?

• 6:40Speaker 02

  That's a good question. They are obviously similar. In both cases, you're reducing the temperature. And so basically by taking energy out, you're slowing things down. The way refrigeration works, the way cold works is it slows things down. So the bacteria that would be metabolizing and reproducing and turning your food bad, they're just growing more slowly. Everything happens more slowly in the cold. And so that's true of both. But freezing goes a step further by locking up the water. And without water, then all of those processes that would lead to decomposition just basically stop. So they're parallel, but with a slight tweak.

• 7:25Mike Carruthers?

  Same people working on it? Or did they show up in different spots and then sort of get merged together in the refrigerator freezer?

• 7:33Speaker 02

  Oh, yes. Good question. Very different people working on it, actually. So at first, refrigeration came first, just lowering the temperature. And it was actually an Australian printer who was the first to come up with a working refrigeration machine and sell it. And the place he sold it to was actually a brewery, one in London and one in Australia. Beer brewers, lager beer brewers were the pioneers in refrigeration because it's very hard to make lager beer. The yeast doesn't like being too warm. In the summer, you really need refrigeration. So they were the ones who said, hey, this new technology works for us.

• 8:15Speaker 02

  So that was happening in the mid 1800s. Freezing was a whole different set of problems because the thing about locking up that water is it forms ice crystals. And those ice crystals can damage cell walls. Everyone's experienced this. Try and freeze a strawberry. It's very hard to do. It's sort of mushy when it comes out. That's the effect of those ice crystals breaking down the cell walls. And it took Clarence Birdseye to figure out that if you froze things super quickly, you could get around a lot of that breakdown and keep the texture relatively intact. So yeah, they operated separately and for a long time, people didn't have freezers.

• 9:00Speaker 02

  And then for a long time, they didn't have combined fridge freezers. And so they, although they work roughly in the same way, they only kind of met in our kitchens relatively recently, post-war.

• 9:13Mike Carruthers?

  Isn't that interesting that the two things happened differently? And Clarence Birdseye, I mean, he's kind of a legend and his name is still on, I think, a lot of frozen food. And he was kind of the big pioneer in, in freezing food that the way you just described that made it work.

• 9:30Speaker 02

  He was, but you know what he did? He froze a load of food and then he realized, oh, wait, no, I have no way to distribute this. Stores have no way to sell it and customers have no way, no way to store it at home. So that's one of the interesting things about this whole technological development too, is that everything has to come along at once. If you, if you don't have anywhere to keep your frozen fish stick at home, then there's no point having a fish stick.

• 10:01Mike Carruthers?

  Well, right. Well, you know, it's also kind of like, you know, who's going to buy the first telephone? There's no one to call, but, but

• 10:07Speaker 02

  Exactly.

• 10:08Mike Carruthers?

  Somebody has to go first. Somebody has to be, and then it kind of stumbles along until it finally clicks.

• 10:15Speaker 02

  And then we're all, now you get to the stage where we're all locked into this and it seems completely weird to imagine even living without a fridge or a freezer.

• 10:26Mike Carruthers?

  So I have heard that a lot of the food we buy at the store, that's, you know, fresh produce, actually sits in refrigeration for weeks, months, maybe years before it gets to the store? Is that possible?

• 10:42Speaker 02

  It is indeed possible. If you go to the store in June or July and you buy an American apple, it's probably coming up on its first birthday. And the reason for that is really simple. Apple harvest is starts in late August and runs maybe through November. So think about it. That apple has to be getting on a bit if you're buying it in the store in June. I just, most people don't think about it, but produce has seasons, yet we can buy it all year round. And apples are one of the most interesting. Actually, they were really one of the first pieces of produce to be successfully refrigerated in this

• 11:22Speaker 02

  way. And the life extension technology we use for apples is, well, to mix my metaphors, bananas, because it relies on not just making them cold and slowing down their death that way. And by the way, the apple is still breathing all the way up until you eat it. The apple is still breathing and burning through its own internal resources. And the trick with slowing that down is just to sort of sedate it and have it take as few breaths as possible on its way to you. Now, cold will do that. The other thing they do is also just reduce

• 12:02Speaker 02

  the oxygen levels. So the apple is sitting in very, very reduced oxygen levels in the most sophisticated warehouses. It's actually controlling the oxygen levels itself. It's a dynamic system that adjusts to how fast the apples are breathing in and out and controls the levels with it. And they just sit there in the dark in these oxygen-starved cold environments, breathing very, very, very, very slowly. And then you buy them nine, 10, 11 months later.

• 12:33Mike Carruthers?

  See, I've always thought that

• 12:37Mike Carruthers?

  The reason you could buy apples in the springtime was because probably somewhere else in the world, they grow apples in the springtime and they grow it. So, you know, it's like, it's five o'clock somewhere, like it's harvest season somewhere. And so that's where the produce comes from.

• 12:57Speaker 02

  Well, that's also true. I mean, so if you, you can buy an American apple in the stores right now, and it will have been stored under refrigeration since last harvest season. It's also harvest season somewhere right now. And guess how those apples are getting to you in a refrigerated shipping container. So either way, it's refrigerated.

• 13:17Mike Carruthers?

  Our topic is refrigeration, artificial cold, and how it has changed your life. My guest is Nicola Twilley, author of the book Frostbite, How Refrigeration Changed Our Food, Our Planet, and Ourselves.

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• 13:47Mike Carruthers?

  So Nicola, when refrigeration first came out, I'm wondering, did people think, you know, it was evil, or that there was something wrong with the food and, and that, you know, we were all going to die if we ate refrigerated food?

• 14:01Speaker 02

  This is the part I found actually the most surprising, along with how recent refrigeration is, is that people were seriously against it at first. They were afraid of it. And if you think about it, it makes sense. Before, if, if you saw a fresh chicken, you knew it had to have been slaughtered a day ago or that day. Now here was this new technology where the chicken could look fresh, but it could have been slaughtered a year ago, 10 years ago. I mean, what is, and people thought this was zombie food, undead, and they didn't trust it. And quite right, because they no longer knew how to know whether it was fresh

• 14:46Speaker 02

  Or not, you know, fresh used to mean something. And if, if, if your food was older than a day or two, you had to have preserved it in some way that would have changed its physical appearance. You had to have dried it, smoked it, you know, canned it, um, done something that would let people know how old it was. And suddenly the fridge comes along and changes all of that. One of my favorite moments is the cold, the, you know, the, the egg, um, Warehousman's Association was really afraid, uh, that Congress was gonna sort of step in and set really short limits for how long food could stay in cold storage warehouses because the public

• 15:24Speaker 02

  was agitating for that. And so they ran a big PR campaign, refrigerated food is safe. Um, and they held these banquets. The first one was in Chicago where everything on the menu had been refrigerated. And you know, today you'll go to a restaurant and you'll see, oh, this is grown by this farmer at this place. On that menu at the cold storage banquet in Chicago, it said, this chicken has been stored for six months at Booth's Cold Storage at, you know, 53rd West 22nd Street. It listed the cold storage warehouses and it was a giant PR attempt to try to prove to Americans that refrigerated food was safe.

• 16:06Mike Carruthers?

  Must have worked.

• 16:07Speaker 02

  Slowly but surely. I mean, even after that first meal, there was a headline in the Journal of the American Medical Association the next day, this means nothing, you know? What happened, honestly, was a woman called Polly Pennington, uh, made refrigeration scientific. She did the research. She was hired by the federal government to figure out how food could be refrigerated safely, what temperature things had to be stored at, for how long to be safe. And she was an absolute pioneer. She was hired at a time when women weren't hired into the civil service and especially not as a scientist. So she was a total rock

• 16:49Speaker 02

  star. And she is the woman who basically got Americans to trust refrigeration wouldn't kill them.

• 16:55Mike Carruthers?

  And it doesn't seem like it kills anybody.

• 16:58Speaker 02

  It doesn't. But does it do them a lot of good? Um, this is the, this is the question I sort of tackled when I looked at, you know, has refrigeration been good for our health? And it's a harder question to answer than you would think. People straight off the bat are like, of course, now we can have fruits in winter. How can it be bad for us? Well, it turns out that, for example, those fruits are much lower in nutrients, vitamins and minerals and phytonutrients than they were in our grandparents' day, in part because of the breeding for shelf life, to be able to be refrigerated. So there's that. There's

• 17:40Speaker 02

  also the fact that we can buy a lot of fruit and vegetables, but we don't necessarily eat them. There's also the fact that, you know, when refrigeration was introduced, everyone was like, oh, this is terrific. We can eat more red meat and be strong. Well, our ideas of what is healthy to eat have changed. Another thing that is increasingly emerging is that it's our gut microbes, the little microbes that live in our gut and outnumber us by trillions to one. They have a huge impact on everything from our health and our immune system to our mental health. And they are profoundly altered by refrigeration because

• 18:23Speaker 02

  prior to refrigeration, we consumed much more fermented food. So, and fermented food full of beneficial microbes that are gut microbes like, that end up having a huge effect on our health. So yeah, pros and cons. On the other hand, salt consumption reduced when refrigeration was introduced. And that's been a huge benefit for public health. So it's a harder question to answer than you think.

• 18:47Mike Carruthers?

  Well, one of the things, one of my pet peeves is, you know, food waste. I hate that so much food gets wasted. And so you would think, well, refrigeration prevents that. But I've always thought that people buy more food than they probably should because they think it'll stay in the refrigerator. And then it sits in the back and goes bad. And then it gets thrown away anyway.

• 19:08Speaker 02

  You've totally nailed it. That is exactly it. So one of the reasons people thought refrigeration would be a great blessing at first is because so much food was lost getting from farms into the city to feed people. A third of all food was was thrown away. And people thought this was just an unbearable waste. And it was.

• 19:32Speaker 02

  Refrigeration did stop that. The problem is that we now throw away a third of the food we buy. So that waste is just sort of transferred where it happens. It doesn't happen on the way to us. It happens once we bought it and we just let it pile up in our oversized fridges. And the fridge, it's like a, I mean, food waste researchers described it to me as a clean, cold waste, waste bin because you put stuff in there. It seems like it's going to be good. Then your plans change and you think, well, it's in the fridge. It's fine. I'll have it tomorrow. Oh, wait, now it's the end of the week. Now it's the end of the next week. It's gone bad. I'll throw it away. People don't even know what's in their fridge.

• 20:15Speaker 02

  Your crisper drawer gets so full that you can't see what's in there. People also don't know what freshness is anymore and they have to look at a sell by date rather than trusting their nose or giving it a quick squeeze. And so that also contributes to waste because they'll throw things out that are perfectly good. So a lot of, and those are all directly connected to, to refrigeration and to the size of US refrigerators and this sort of artificial abundance mindset that they encourage.

• 20:47Mike Carruthers?

  So what do people do? Because there is some food like milk, butter, things that seemingly, well, no, butter doesn't have to be refrigerated. People just do. We don't actually put our butter in the, I mean, we always have some out because it doesn't have to be refrigerated.

• 21:02Speaker 02

  Yeah. And you can spread it that way, right?

• 21:04Mike Carruthers?

  Exactly. But milk does, or it'll, I mean, it'll go bad faster if it doesn't. It'll go bad pretty fast if it's not in the refrigerator. So what did people do before that?

• 21:13Speaker 02

  They made buttermilk. They made yogurt. They turned their perishable products into non-perishable ones. It just so happened that those were different. They had, they had benefits. I mean, I love, there's a famous quote, cheese is milk's bid for immortality. I mean, cheese is a great thing. I personally think cheese is a bit of an improvement on milk. So many of humanity's most delicious foods come out of trying to turn something that's very perishable into something that has a little, little more legs on it.

• 21:45Mike Carruthers?

  You know, I hadn't really thought about this, but if you look at pictures of older refrigerators, like from the 40s and 50s, even the 60s. They were a lot smaller. And today, we have these big refrigerators. And when you have a big fridge, you feel compelled to fill it up. And you fill it up with food. You can't possibly eat all of it before it goes bad.

• 22:06Speaker 02

  U.S. refrigerators are the largest in the world by far and away. You know, they're, they're the nearest equivalent even in Europe are two thirds the size. And most of the world is dealing with something half the size. And that's before you get to the huge percentage of American households that actually have a second fridge in their garage or even a third. There's a lot of fridge space to be filled. And no one wants an empty fridge that feels like you don't have enough. So anxiety provoking. But yeah, you're absolutely right. And I think, you know, fridge designers have tried to solve this. They've tried to give us smart fridges that will tell us what's in there.

• 22:51Speaker 02

  Really, we would waste a lot less if we had smaller fridges and shopped more frequently in, you know, walkable cities. That's possible, but we haven't chosen that route.

• 23:03Mike Carruthers?

  Are there any advances in or on the drawing boards that, that, or is you just make it cold? You, you take your box and you make it cold. And that's the beginning and end of refrigeration.

• 23:16Speaker 02

  I love this question. Preserving food is one of the primary concerns if you're a human. It's up there with, you know, reproduction and, and surviving, you know, and attacks from other animals. This is a, you know, keeping food good so that you can continue to eat it is one of our primary evolutionary drives. And yet, when refrigeration was introduced, most people thought it wasn't going to be the winning solution. There were a lot of people who thought maybe, you know, some kind of coatings or fumigation or there were, there were a whole range of technologies being developed in the 1700s that looked more promising than refrigeration. And frankly, that research is now happening as we understand.

• 24:03Speaker 02

  The downsides of refrigeration, especially in terms of climate, people are picking that back up. And you know, you want your beer cold, you want your ice cream frozen, but your produce doesn't actually need to be cold. It just needs to be fresh. So if you can achieve that with a coating, which company in Santa Barbara is working on, they have a coating that will keep food, produce as fresh, just with that coating, at room temperature as refrigeration would do. You can get four weeks with a bell pepper sitting on the countertop at room temperature, using their, their coating, which is entirely made out of food, food molecules. Now people are working on that. It might be that we don't need refrigeration

• 24:48Speaker 02

  for all of our food. We'll still want a cold beer, but maybe our produce doesn't have to be refrigerated, and that would be incredible.

• 24:57Mike Carruthers?

  Well, it's really, this whole story is really interesting in, in a couple of ways. One, that it is so new, that refrigeration is only 150 years old. And secondly, it just, it affects our lives in so many ways, and it, and yet it's still somewhat invisible. We don't think about it much, but man, imagine life without refrigeration. I've been talking to Nicola Twilley. She is a writer, frequent contributor to The New Yorker, and author of the book Frostbite: How Refrigeration Changed Our Food, Our Planet, and Ourselves. And there's a link to that book in the show notes. Thank you for coming on today, Nicola.

• 25:37Speaker 02

  Thanks, Mike. It's been great.

• 25:43Mike Carruthers?

  Like you, I imagine, I know what a volcano is. I've seen them on TV and in the movies. I know that smoke and lava comes out when they erupt. And that's about all I know. And yet, according to people who do know more, volcanoes are fascinating. They're all over the world, and we should probably know a little more about them. Here to reveal the amazing world of volcanoes is Tamsin Mather. She is a professor of earth sciences at the University of Oxford and author of the book, Adventures in Volcanoland: What Volcanoes Tell Us About the World and Ourselves. Hi, Tamsin, welcome to Something You Should Know.

• 26:23Speaker 03

  Hi, it's great to be here.

• 26:25Mike Carruthers?

  So first, I guess we need to understand what a volcano is. So what is a volcano?

• 26:32Speaker 03

  So volcanoes are places on our planet where molten rock, that we call magma, when it's inside the planet, and lava, when it gets to the surface, comes to the surface. And volcanoes are the structures that are built. So we often refer to volcanoes, they look like mountains, but they can actually also be big depressions in the ground as well. So think about big craters or big calderas, like Yellowstone or Santorini in Greece.

• 27:02Mike Carruthers?

  So my image of a volcano, and I think for most people, is it's a mountain. It's a mountain with smoke and lava coming out, like Mount St. Helens. Do volcanoes create that mountain? Or do volcanoes use a mountain that already exists to erupt? You know, which is the chicken and which is the egg?

• 27:24Speaker 03

  Yes, so in the case of Mount St. Helens, it's what we call a strata volcano. It's been made up of layers of lava and ash and other volcanic products that have been erupted. So yes, in the case of Mount St. Helens and many other volcanoes, the mountains have been built by the volcanic activity.

• 27:45Mike Carruthers?

  What causes a volcano to basically, at some point, they all stop doing what they're doing? Why do they stop?

• 27:53Speaker 03

  That's an excellent question. It's not something we fully understand. So in some cases, we do have a really good understanding. So Hawaii, for example, is fed by a hotspot underneath the volcanoes. So again, it's down in the in the earth's mantle. And as the rigid Pacific Plate rides over that hotspot, it actually takes the volcanoes away from that source of magma. So Kilauea and Mauna Loa are the active volcanoes at the moment. But as you go over to the west along the Hawaiian chain, the volcanoes become extinct. And that's because they've actually moved away from the source of the of the molten rock that fed them.

• 28:38Mike Carruthers?

  Ever since I was a child, my theory, or my understanding of what volcanoes are, and I think a lot of people grow up thinking this, is that, you know, somewhere in the center of the earth is this fire, that the earth has got fire in the middle of it, and the volcano is that fire coming up. How accurate, how accurate is my childhood theory?

• 29:04Speaker 03

  Well, that turns out not to be quite correct. But, but actually, in a funny way, it's where we started, where the science started. So hundreds of years ago, people thought basically that's what volcanoes were. They thought that that was where earth's internal fires found their way to the surface, very much like your, your idea there. People had these ideas of the bigs of chimneys for earth, earths in a fire. And then even when when Christianity took a hold, people thought of them as being gateways to hell, even. There's there's, you know, incredible stories of the conquistadors erecting crosses over Messiah volcano in Nicaragua to to to guard the escape of evil spirits from its mouth.

• 29:51Speaker 03

  But since the modern era of science, we've been able to understand much more about our planet's internal structure. And using seismic waves, which are basically the vibrations that we feel coming through the earth when there are big earthquakes, for example, we can record those and we can learn a lot more about the internal structure of the earth. And what we find is that most of the earth is solid, rather than having any pockets of melt that stay there all the time. The very inside of the earth, there's a liquid outer core, but the mantle, which is the bulk of the earth, this is about sixty-five percent of earth's mass, is actually, most of the time, solid.

• 30:35Speaker 03

  And it's only in these very special circumstances where it melts and you get magmas generated that feed volcanoes.

• 30:43Mike Carruthers?

  So my theory, at least I share my theory with a lot of other people, at least centuries ago, they believe what I believe.

• 30:50Speaker 03

  Yes, absolutely. You're doing well, just a few centuries out of date.

• 30:54Mike Carruthers?

  That's okay. And then, so then we moved to science class, and I remember in science class, that for there to be fire, you need oxygen. If this is going on underneath the surface of the earth where there is no oxygen, how can there be fire?

• 31:11Speaker 03

  Exactly. So this is not fire in the same way as a bonfire or a fire that we might have in, you know, the greater Christmas time or something like that. This, nothing is burning with volcanic heat. The rock is red hot when it comes up to the surface. So many of the things that we refer to as fire in a volcanic sense actually aren't fire at all. Nothing is burning. There's nothing you can put out. Things just cool down. So it's a very different type of process.

• 31:46Mike Carruthers?

  How good is science at predicting volcano eruptions?

• 31:51Speaker 03

  We're getting better and better, but it's still really, really challenging. So we have lots of well monitored volcanoes. You get a lot of really useful data. So seismic data, which is the very small tremors and very small earthquakes that you get when magma or gas move in the earth's crust, gives us lots of really useful information. And then the changing shape of volcanoes is also really important for us. So just an example, in 1980, before the Mount St. Helens eruption, it kind of blistered up like a boil on the side of the volcano.

• 32:30Speaker 03

  And then there was a small earthquake and it was from that swelling that the eruption initiated. So we can pull all these different strands together in order to make a prediction that a volcano is very likely to erupt. But it's only generally a forecast. It's a bit like weather. We can't be sure. And the other challenge that we have is that we might be able to say, it looks like it's going to erupt in the next month. But actually saying it's going to erupt in two days' time, which is a really helpful piece of information if you want to evacuate a big city, is much more difficult to do.

• 33:07Mike Carruthers?

  And even when you do predict that a volcano is going to erupt, can you predict with any kind of certainty how much it's going to erupt, how big an eruption it's going to be?

• 33:22Speaker 03

  That's another big challenge. And often we go back and study its past behaviour in order to try and understand its future behaviour. And sometimes we can use things like how much it's deformed, how much it's swollen up, to give us some clues about how much magma has arrived in the system.

• 33:41Mike Carruthers?

  Are volcanoes monitored actively? Are there people over there going, let's keep our eye on this one every day?

• 33:48Speaker 03

  Well, in some places, yes. So the USGS do a great job monitoring the US volcanoes. And they have a lot of resources and a lot of expertise and people are monitoring that. In some parts of the world where there are fewer resources, volcanoes are not as well monitored. And in some places, they're very remote from populations. So again, maybe it's a little less important to keep them well monitored at all. But a really powerful tool we have now actually are satellites. So we can use satellite remote sensing, basically satellites that send radar beams down to the the surface to map the shape of the surface.

• 34:31Speaker 03

  We could actually use these types of satellite to monitor volcanoes globally without needing there to be infrastructure on the ground.

• 34:40Mike Carruthers?

  Have you ever seen one?

• 34:42Speaker 03

  An erupting volcano?

• 34:43Mike Carruthers?

  Yeah.

• 34:44Speaker 03

  Yes, absolutely. It's it's one of the, well, I think one of the most astonishing, awe striking things that you can experience as a human.

• 34:55Mike Carruthers?

  And maybe a little frightening?

• 34:58Speaker 03

  A little bit. I think I think it's important that one is a little bit frightened. I mean, these are enormously powerful forces and they need the, you need to show them due respect.

• 35:09Mike Carruthers?

  Yeah, I guess it depends on how far away you are as you're observing it.

• 35:12Speaker 03

  And the type of eruption as well.

• 35:16Mike Carruthers?

  And so when a volcano erupts and when I imagine the images of Mount St. Helens and, you know, it all, in addition to the lava, which is very dramatic, you, there's also a huge amount of smoke or whatever that is. And how dangerous is that? Is that a real concern?

• 35:36Speaker 03

  Yes, so the gases that come out are a cocktail of different components. So there's a lot of steam in the gases, a lot of, a lot of water. And that doesn't tend to cause so many problems. There's a lot of water vapor in our atmosphere anyway. We see it every day as clouds. But there's also a lot of sulfur dioxide, which is an acidic gas and other acidic gases like hydrogen chloride and hydrogen fluoride.

• 36:06Speaker 03

  So in the local vicinity, places like Hawaii, where you have gas coming out of these volcanoes all the time, you can get quite substantial drops in air quality and acid rain problems, damage to vegetation.

• 36:19Mike Carruthers?

  Can volcanoes ever be so big and it's and the eruption so big that they alter the climate in some way, that they change something that or is it a dramatic yes, but it's temporary and things eventually go back to normal?

• 36:38Speaker 03

  Well, this is a app. This is a really fascinating question. So volcanoes actually alter our climate and environment in huge number of different ways. But just to give you an example, if we have a really big eruption, which punches up material up into the upper atmosphere, so the layer of the atmosphere known as the stratosphere, which you might know about because it's where the ozone layer is, which is obviously very important to our existence. If it punches up into that layer, basically, the sulfur dioxide can can oxidize to fill to form a haze, a kind of veil of aerosol that can make the atmosphere really hazy high up. And that can reflect some of the sunlight back off into space

• 37:20Speaker 03

  and actually cool the planet lower down. So a really good example of this was in 1815, there was an enormous eruption of Mount Tambora in Indonesia. And this altered global climate patterns really profoundly. So the year 1816 was known in Europe and North America as the year without a summer. We had things like snow in New England in June, we had crop failures, we had been famine in various parts of the world. People were forced to eat their their cats rather tragically in Switzerland. There were riots in France. There was a great push of migration from from New England to the Western States in the US.

• 38:04Speaker 03

  And that was all caused by the volcano changing the global weather patterns.

• 38:09Mike Carruthers?

  Wow, I never knew that. That's fascinating. That I never heard that before. That that's that's pretty big. That's big news.

• 38:18Speaker 03

  Yes. And one of the really interesting things was at the time, people didn't connect these phenomenon up.

• 38:24Mike Carruthers?

  Yeah, imagine.

• 38:25Speaker 03

  It's only subsequently that we've really learnt this.

• 38:27Mike Carruthers?

  Right, yeah, I would imagine the science wouldn't have been available to say, well, the reason for that is this, and this is why it's happening. And people must have been very confused and wondered, well, what's going on, you know, the end of the earth?

• 38:40Speaker 03

  Yeah, totally.

• 38:41Mike Carruthers?

  Yeah.

• 38:42Speaker 03

  Yeah. So really, the eruption that people really became aware of was in 1883, which is the Krakatau eruption, again in Indonesia. And this was, this did not have such a profound effect on global climate. But because we had the undersea telegraph cables in place, news could travel around our planet much more quickly. So people were aware of this eruption within hours of it happening, and started looking for phenomenon, looking for changes, so looking for amazing sunsets, which they saw, and evidence of the pressure wave traveling around the planet in terms of barometers and things like that. So actually, it was the communications technology at the time really changed the way that we

• 39:26Speaker 03

  experience and understand volcanoes.

• 39:29Mike Carruthers?

  Once a volcano has erupted, is there always the potential that it can erupt again? Or are you able to identify some volcanoes, these are dead, and we'll never hear from them again?

• 39:43Speaker 03

  So, some volcanoes, the tectonic plates have rearranged themselves, since they've been moved away from the source of, the source of their magma. Other volcanoes do seem to have gone, gone dead, just because they haven't erupted for a very long time. And often, we can't exactly work out why. It's just that the focus of the, the way that the magma finds its way to the surface seems to have shifted. So, so we, we can, we can definitely make, again, a very good forecast, a very good sort of, a very good prediction that that volcano is unlikely to erupt again. But the, these are unpredictable mountains, so they often have the last words, and sometimes they still can take people by surprise.

• 40:28Mike Carruthers?

  Is there any sense of the last volcano that erupted for the first time? Like, this was the first time this mountain spewed out that stuff? Or do most volcanoes that we see for the last, I don't know, couple hundred years, they've erupted before?

• 40:47Speaker 03

  Oh, there's plenty of examples of new volcanoes. So in some ways, the activity that's going on in Iceland at the moment on the Reykjavik Peninsula, these are new fissures that are opening up all the time. We don't really have a central volcano there. This is, these are more like fissures that open up and spew forth lava flows. But another, another famous example is the Paracutin volcano, which was, it was basically sprung up one otherwise normal day in a farmer's field in, in Mexico.

• 41:24Mike Carruthers?

  Do volcanoes ever erupt or does volcanic activity ever occur in places where it wasn't expected? Or do you pretty much know where it's going to happen, generally speaking?

• 41:37Speaker 03

  Generally, they come up in places that we expect volcanism. So in, in areas that have had other volcanoes going off in the past or other similar types of fissure eruptions in the past, they don't normally come up and, they don't normally come up in completely unexpected zones away from other volcanic activity.

• 41:57Mike Carruthers?

  When lava flows out of a volcano, how hot is it? How hot can it get?

• 42:04Speaker 03

  So the basaltic lavas that come out of volcanoes like Kilauea in Hawaii or the volcanism on Iceland are getting on for about 1,800 degrees Fahrenheit.

• 42:16Mike Carruthers?

  Is there anything about volcanoes that you've seen in the research that would surprise people?

• 42:22Speaker 03

  One of the things that fascinates me about volcanoes is we would not be here, I don't think, as a species if it was not for volcanoes.

• 42:30Mike Carruthers?

  How so?

• 42:32Speaker 03

  Although we think of volcanoes probably most often as forces for destruction, they've also been really important forces in terms of building our planet's continents, which we're obviously land-based mammals, so really important. The gases coming out of volcanoes help to maintain our atmosphere over geological time. So they've, they've kept us within certain bounds of temperature by our atmosphere helping for that and protected us, the atmosphere protects us from lots of external forces. And then there's even some thinking that volcanic lightning or the hot vents on the ocean floor might have been some of the first places that the molecules for life

• 43:16Speaker 03

  were put together that laid the foundation for all of life on this planet. And I think that's incredible.

• 43:23Mike Carruthers?

  Well, that puts the subject in perspective that we we might not be here if it weren't for volcanoes. I've been speaking with Tamsin Mather. She's a professor of earth sciences at the University of Oxford. And the name of her book is Adventures in Volcano Land: What Volcanoes Tell Us About the World and Ourselves. And there's a link to that book in the show notes. Thanks, Tamsin. What a great topic. Thank you.

• 43:49Speaker 03

  Thanks, Mike. It's been really fun.

• 43:51Mike Carruthers?

  Here's a question for you. If you carry a purse, and the question is, when was the last time you washed it? Those things are crawling with germs. Tests conducted by a hygiene solutions company found that leather handbags are the worst offenders because their porous texture provides the perfect growing condition for bacteria inside there. And the handles on your purse, they're probably the dirtiest feature of all. There's enough bacteria on the handles to cause a real health concern. The outside bottom of the bag is pretty bad, too. I mean, we think about it. Your purse sits on all kinds of unsanitary

• 44:35Mike Carruthers?

  surfaces and then ends up resting on your desk or the kitchen counter. And it's it's just kind of gross. So it might be a good idea to figure out the best way to give that thing a wash. And that is something you should know. The next time you're in a conversation and the subject of podcasts come up, I hope you remember to recommend this one. People like recommendations and well, and we like new listeners. I'm Mike Carruthers. Thanks for listening today to Something You Should Know.