Science Friday - Can We Just Throw Our Plastic Garbage Into A Volcano?

Episode Date: December 15, 2025

It’s winter, and the SciFri team is already dreaming of warmer weather. How about a mind vacation to one of the hottest places on earth, an erupting volcano? Tamsin Mather has trekked to volcanoes in Chile, Guatemala, Italy, and beyond to learn their secrets. She joins Host Flora Lichtman to field your burning volcano questions, like what’s the deal with glass shards that look like hairballs? Guest: Dr. Tamsin Mather is a professor of Earth sciences at the University of Oxford in the UK.Transcripts for each episode are available within 1-3 days at sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Hi, I'm Flora Lickman, and you're listening to Science Friday. As you might have noticed, it's winter. And I am already dreaming of warmer weather. So how about a mind vacation to one of the hottest places on Earth, an erupting volcano? We asked you for your burning volcano questions, and you have been blowing up our voicemail. Hi, this is Kathy. I'm from Boulder, Colorado. And I have this question that nobody seems clear about.

that is, why are we not able to drop large amounts of plastic debris right into a volcano? Could volcanoes be the solution to plastic waste disposal? I just want to hear a volcanologist point of view. Thank you. Kathy, we have just the volcanologist for you. Tamson Maylor has trekked to volcanoes in Chile, Guatemala, Italy, and beyond to learn their secrets. And she is here to field your questions. Tamsin, welcome to Science Friday. Hi there.

Okay, first of all, let's start with Kathy's query. What are your thoughts on treating volcanoes like giant trash incinerators? Well, I really like Kathy's idea that, you know, we definitely need to do something about all our plastic waste. So, you know, it's good to have creative solutions. We do incinerate plastic waste in incinerators, and we can use that to generate heat energy, which has some payback. The problem we're throwing it into an active volcano is that active volcano is very hot.

And so what that will do is burn the plastic debris. This releases toxic fumes as well as other stuff, as well as carbon as well, of course. And the issue when you're doing that in an active volcano is it's quite tricky to fit active volcanoes with good filtration devices to get rid of it. all those toxic fumes, whereas we have a much better chance of doing that if we do it, if we burn plastic waste in incinerators and generate heat energy and electrical energy as well.

So it's a great idea, and we do it on our sort of human scale in some parts of the world. But the problem is we don't then have any control over the toxic fumes coming out and they just get dispersed into the atmosphere. Thank you for your question, Kathy. Tampson, I mean, could you harness volcanic heat in some other way? Yeah, absolutely. And some parts of the world are doing that in really great way. So I was just in Iceland earlier this year.

In Iceland, they have a big program of harnessing the heat of their volcanoes. So they drill into the volcanoes and extract hot water that's flowing through the volcanic edifices and use that to drive turbines to get electricity. They also put it through heat exchanges and heat hot water that they pipe down from the highlands to the cities like Reykjavik. And I think about 80% of heating or space heating and hot water in Iceland is actually driven by geothermal power. So if you take a trip to Iceland,

you can have the longest, hottest shower that you want or bath and feel absolutely no carbon guilt about it. Have you accidentally dropped anything into hot lava and what happened? No. I'm actually really pleased to say I haven't because I feel that would be kind of careless, really. I have watched people sampling lava. Actually, sampling lava is harder than you think. So sometimes when you see videos of it, it looks like it flows really easily.

So particularly the types of lava we see in places like Hawaii, which are a type of rock called basalt. They can look really easy. They can look like they're flowing really, really, really easily. But actually, if you try and sample them, they've got a strength to them that we're not used to in water-based fluids, which is water-based liquids, which is mainly our experience as a day-to-day, as a species. So actually to get stuff, to get a sample of larva,

you have to push really hard into it or sort of hacked it, with a hammer or something like that. Really? And you need a special protective equipment. A hammer. So if you dropped something on a lava flow, it would sit on top of the lava flow in most cases and burn unless it's made of heat-resistant material.

So sometimes if you see things like in Lord of the Rings, when the Ring kind of, when Gollum kind of falls into the lava in the film and gets kind of almost like he's falling into a pool of hot water. I don't know that's not very realistic. I think it would be much more likely he would sit on top of the lava flow and just burn up and it would be the heat that killed him. We're myth-busting that one for people today.

He would just sit on the lava and burn up. Yeah. Okay. Next question. Hi. I am curious about lava in that how close could I be to it without protection? How close can you get? Well, I think that there's a lot of that question, right? How close do you want to get? It depends on the type of lava flow again.

If you have a lava flow going a very oozy or very low viscosity, so not a very sticky lava flow coming down quite a steep slope, I think you want to be pretty far away because just to keep safe and keep away from it. Do you have a lava flow that's flowing over ice or water? That can kind of get unpredictably explosive. So again, I'd be really, really careful about a lot of. approaching those. But if you have things like some of the flow fronts on Hawaii that are relatively stable

and they're kind of doing these outbursts that you can see happening, you can get pretty close. I mean, you can see pictures and video online of people actually in the recent Icelandic eruptions. And they're kind of cooking hot dogs, putting coffee pots on the flow fronts, you know, cooking bacon and egg. and stuff like that. So you can get very, very close, but you would need to have oven gloves

and that type of thing, I think. I mean, I've stood near lava flows on Mount Etna, for example. And the heat on a fresh lava flow, in particular one actively flowing, is really impressive. You know, if you've sat next to a bonfire or a far in your grate at home,

and you kind of lean in and you can feel that real burning on your face and you think if I go a bit closer, or it so that's really getting uncomfortable. It's like that, but on steroids. You know, it's really, really, you're right on the edge of it and you feel quite nervous that if you move any further, you're going to do yourself some serious harm.

Wow. So I think the answer to the question is it depends a bit. I have to say that cooking my breakfast on a lava flow is massively on my bucket list. I've wanted to do that ever since I was a kid and I saw it on television. I was going to ask you if you've done it. Why haven't you?

Just never been the right time, the right place for the frying pan and the right side of bacon. You had to put that in your pack for the next time. Absolutely. We have to take a break, but don't go away because when we come back, we are getting on that volcano with Tamsin to hear what it's really like to do this fieldwork. We got an email from a listener, Susan, who asked, do volcanoes have different temperatures? Yes. Yes, they do. So basaltic volcanoes like Hawaii are the hottest ones,

so there are about 1,000 degrees. And then strangely, actually, the more dangerous volcanoes, the more explosive volcanoes, like those in the Pacific Ring of Fire, that are very famous, big explosive eruptions like Mount Pinatubo. They have slightly cooler magmas. So you're not going to really notice it yourself, but they can be down more like sort of 700 to 800 to 800 degrees Celsius.

Is that because they were coming from different, parts of the earth? Not exactly. Most magmas start off as basalts. So we have the different layers of our planet. So we sit on the crust, and then beneath the crust, we have the mantle. And most magmas are generated by melting the mantle. So the mantle is not liquid, usually.

It's usually a solid. It's very hot solid. So it's able to move very slowly. The mantle very, very slowly convex. So it convex about the speed that our fingernails grow. So it creeps along. But in certain special places in the earth, it melts. And when it melts, you first of all, first of all get a basalt.

So that's the chemistry. And that's the kind of runny lava that we see in Hawaii. But if it takes a bit longer or there's more water in that basalt like you get in subduction zones, like the Pacific Ring of Fire, it tends to change. change on its journey up to the surface. As it changes, it cools down as well. And the chemistry changes, which also makes it more explosive. I mean, speaking of Hawaii, the Big Islands Kilauea volcano, I understand, is erupting right now. And we got a listener question about it. Hi, this is Jackie calling from Schoenberg, Texas. And recently, my husband and I went to the

Big Island, and we were fortunate enough this summer to see the erupting Kilauea. And I was curious to learn just how worried spectators should be about the fallout of what they call Taley's hair, what kind of damage that might do to one's health, observing an eruption that about maybe an eighth of a mile away from the eruption? Tamson, what is Pelley's hair? Well, first of all, lucky Jackie, getting to see that. So, well, Pelle is the Hawaiian goddess of the volcanoes. And so Pellé currently in the belief system lives in Halamama crater,

which is on Kilauea. So Pellet's hair is named after her. Pellet's hair is amazing stuff. It's basically formed when a basaltic lava erupts or when bubbles burst even on a lava lake surface, you get this extrusion of glass fibres, so this stretching of fine glass fibers. And then they break and they come up with the hot gases and they collect. on the ground, they fall out on the ground, or they collect around vegetation or any rocks that you have.

And it looks remarkably like animal hair, but it's actually more like glass wall or something like that you might use for DIY, for home tasks. But it's these extruded glass fibres that you get. And it's incredibly beautiful. But it's so realistic as animal hair, animal hair. I once sent some samples of it for a colleague of my colleague of my, mind Australia to analyze. And it got impounded in customs because they thought it was I was trying

to import animal products into Australia. So I had to write a very long letter to them explaining what it was, inviting them to open up the bag and have a feel of what it was like. And it did actually get to Perth in the end. They should not be particularly dangerous to people downwind. I mean, there are plenty of nasty chemicals if you're inhaling volcanic plumes. And ideally if you were inhaling them for any length of time, or even just for a short time at close quarters, you should wear a gas mask to protect you. But as a tourist visiting, I think the impact would be relatively low.

Pelle's hair fibres are quite large, so they shouldn't get very deep into your respiratory system. There can be other volcanoes where you have harmful crystals, so more like asbestos fibres, in the volcanic fumes, but not so much in volcanoes like Hawaii. Okay, so we have hair, we have hot fluids, any other body adjacent parts coming out of volcanoes? I hadn't really thought of it like that. I'll have to give that some thought.

Do you have a favorite eruption? Oh, that is an excellent question. I don't know about a favorite eruption, but I've definitely got favorite volcanoes. Tell me. Mount Etna on Sicily is a very special place to work and I've worked there a lot. It's an absolutely beautiful volcano on a beautiful island. It changes every single time I go up to the summit which is, I find quite moving actually just to sort of see it shifting on a very human time scale. It's also a wonderful place to work. I've got great colleagues there working in the INGV in Italy and in the University of Palermo and Catania.

And I think it's the only place I've done fieldwork and actually gained weight. When you go to Italy, you eat and you eat so well and so frequently that you can't even burn the calories climbing the volcano every day. That's the best problem to have, in my opinion. Yeah, I'm not complaining. The other place that springs to mind is Villarica volcano in Chile, which is one of the volcanoes I did my PhD on. and it is just such a beautiful mountain. It has this perfect conical structure. It has an ice cap.

So you slog up the ice cap with all the equipment. Some days, using crampons and such like. And then at the end of the day, you slide down on ice shoots, which is a lot of fun. Amazing. Will you put me on Aetna during an eruption? Is there a smell? Is there a feel in the air? What does it sound like?

Sort of set the scene for me. Yeah, I mean, again, a particular experience brings to mine. So I live in the city of Oxford, and I have done since 2006. I really shortly after moving to Oxford, I set off really early one morning. It was a summer morning. So I'm walking through the kind of leafy streets of Oxford, got on a bus, got on a couple of planes. And by the evening, I was standing next to an erupting vent on Mount Etna. and the whole colour palette was completely different

how I started my day. Everything was black and orange and yellow and red. And the amazing thing about being near an erupting volcano is the booming sounds are incredible and you hear them through your ears but you also feel them through your body. So it's not just because they're so loud that you feel the sound waste of your body.

You're also feeling the vibrations because they're coming from inside the earth actually travelling through the ground and up through your up through your body as well. So it's an incredible kind of sound experience because the sound is kind of hitting you from all directions. And then there's the smells. And I guess the most overwhelming smells in volcanic areas are normally the sulfur gases. So in that particular instance on Mount Etna, it was mainly a sulfur dioxide smell. and that's a bit like a kind of acrid burnt matches type of smell.

And you can feel it as well as smelling it because it kind of the cocktail, the volcanic gases, kind of burns you a little bit as well if you take your gas mask off and you can feel it in your eyes also. In some other volcanic environments, listeners might recognise the kind of classic rotten egg smell, which is hydrogen sulfide. I think those are the two most easily identifiable smells. but being near an erupting volcano is an incredibly overwhelming experience because I think it sort of hits you really through pretty much every sense you own. Tamson, thank you so much.

This was so delightful and so transporting. No problem. Volcanologist Tamson Mayther. She's at the University of Oxford in the UK. And thank you to everyone who called in with questions. We loved hearing them, and I'm so glad we could get you answers. This episode was produced by Kathleen Davis. Thanks for listening. I'm Florida Lichtman.