Note: Threshold is produced as a listening experience. If you are able, we strongly encourage you to listen to the audio, which includes emotion, emphasis, and subtle nuance that’s not conveyed in the text. We create our transcripts using a combination of speech recognition software and human transcribers, and as such, they might contain errors. Please check the corresponding audio before quoting in print.

Nick Mott This season of Threshold is underwritten by the Pulitzer Center on Crisis Reporting.

Travis Yost Hello there!

Amy Martin Hey, how are ya?

Travis Yost Good, how are you doing?

Amy Martin I’m good. Thanks for being game.

Travis Yost Yes, of course.

Amy Martin Welcome to Threshold, I’m Amy Martin and this is Travis Yost. He makes the music for our show. Including, this music.


Amy Martin I called Travis up randomly and asked if we could have a quick conversation. On tape. I told him I wanted to ask him three questions. I didn’t tell him what they were, and I didn’t tell him that the answers contained crucial information for understanding climate change in the Arctic.

Amy Martin First of all, will you verify for me that you have no idea what I’m talking to you about? I didn’t give you any warning here.

Travis Yost Wait, I can verify that I have no idea what you’re talking about. Sure.

Amy Martin [LAUGHS] OK. What is carbon? What do you think carbon is?

Travis Yost Carbon is the basis of everything?

Amy Martin [WHISPERS] Nice.

Travis Yost Everything has carbon. Everything is, everything is carbon-based that is a life form, I believe? Hence the phrase “carbon-based life form?”

Amy Martin [LAUGHS] Awesome. And would we find carbon on the periodic chart anywhere?

Travis Yost Oh, I don’t think you do.

Amy Martin OK, you do.

Travis Yost Damnit!

Amy Martin [LAUGHS] Yeah, it’s in there. It’s just the C. It’s a C.

Travis Yost Oh, OK.

Amy Martin But the first part of what you said was exactly right. So, is there a fixed amount of carbon on the planet, or can the amount of carbon on the planet grow and shrink over time?

Travis Yost I don’t think it’s fixed. I think it’s, or it’s, if it’s fixed, it’s gotta have something to do with, like carbon dating something is a reduction in carbon from an object or something. So it’s carbon that’s leaving whatever object. So, a fixed amount seems, if I had to guess on Jeopardy, a fixed amount seems wrong. But that would also seem really cool, that there’s a fixed amount of carbon and it was just being rearranged into everything else. But I’m going to go with reduction.

Amy Martin Oh! You were so close!

Travis Yost So close! [LAUGHS]

Amy Martin There is a fixed amount and it is getting rearranged into different things.

Travis Yost Oh, yes! Awesome! I love that kind of stuff. OK, I love that!

Amy Martin Yeah, carbon, carbon has as cycle, just like the water cycle. But except for it’s not just like the water cycle, because the water cycle is much easier to understand, it’s a lot simpler. But carbon, basically yeah, we have a fixed amount of carbon, and it moves around the planet over long periods of time taking different forms. Like, it can be in a rock, it can be in you, it can be in what you ate, it can be in the air, it can be in the ocean. But it’s a fixed amount and it’s all just getting transformed into one form or another over time. Isn’t that cool?

Travis Yost Yes, that is awesome. I like that. I like when science is kinda cute.

Amy Martin After spending two episodes with the people of Shishmaref, Alaska, we’re now switching gears. We’re going to far northern Sweden, to hang out with some Arctic researchers. But before we head out, I wanted to these basic facts about carbon out on the table. First, carbon is a key ingredient for organic life. In fact, it’s kind of built into the definition of organic life. Organic chemistry is carbon chemistry. And second, it moves in a cycle. I think this is something that gets missed a lot, when we talk about the amount of carbon dioxide ticking up in the atmosphere. It’s not that our human activities are creating carbon – we’re not making more of this stuff. What we’re doing is moving it around: we’re taking it from places where it’s been sort of locked away, like below the Earth’s crust, and then burning it, which moves a bunch of into the atmosphere and the oceans. In April of 2018, there was an average concentration of 410 parts per million of carbon dioxide in the atmosphere. That’s more carbon in the air than the Earth has seen for at least 800,000 years, maybe longer.


Amy Martin So, who cares? Carbon moves around. Sometimes it’s below the Earth’s crust. Sometimes it’s up in the air. Why is the amount of carbon in the atmosphere something people get so worked about? Well, the crux of the issue is this: when carbon is buried underground, it doesn’t affect us all that much. But when it’s hanging out in the atmosphere, it warms up the climate. And this is where the Arctic comes in. Because one of those places where a lot of carbon has been in a sort of resting state for a really long time is in the frozen soils of the polar north.

Gesche Blume-Werry This frozen soil that we’re sitting on is important for everyone over the whole world. And what happens here should be of concern to everyone no matter where they live.

Amy Martin This is Gesche Blume-Werry, and she says this relationship between carbon and frozen soil is actually more of a ménage à trois – there’s an interloper here, a third party with powers far beyond its size. We’re going to expose all of the seamy undersides of this love triangle on this episode of Threshold.



Amy Martin I’m in a grassy meadow in the mountains of northern Sweden, watching Gesche Blume-Werry stab the soil with a long metal pole.

Gesche Blume-Werry It’s called a permafrost probe. So this is a steel rod. So this gives us an indication of how much of the soil is frozen or not frozen.

Amy Martin Gesche’s from Germany. She’s an ecosystem ecologist, and she’s been researching Arctic plants here in Abisko, Sweden for the last six years. She hasn’t pushed the probe into the soil very far at all before it hits something. Something that sounds like a big rock.


Gesche Blume-Werry This is not a stone. This is frozen soil.


Amy Martin She pulls the probe back out.

Gesche Blume-Werry And then if you touch this?

Amy Martin Wow.

Gesche Blume-Werry It’s really really cold.

Amy Martin That’s a trip.

Amy Martin In just a few seconds, the end of the pole has become so cold that it’s uncomfortable to touch. It’s almost eerie, like it picked up a message for us from a hidden world right under our feet: the secret world of permafrost.


Amy Martin The official definition of permafrost is just soil that has been frozen all year round for two years or more. But in many parts of the Arctic it’s been frozen since the last Ice Age. There’s a lot of variety in permafrost: it can be anywhere from a meter to a kilometer thick. It can be very very cold, or just barely frozen. And in different places all across the Arctic, it’s starting to thaw. You don’t need a permafrost probe to see it. Roads are sinking and buckling, homes are shifting and cracking, and trees are tilting at awkward angles, giving rise to the label “drunken forests.” In fact, there’s a line of telephone poles next to the meadow where Gesche and I are standing, and one of them looks a little drunken too.

Gesche Blume-Werry That one that is kind of tilting now, that is probably standing in an area where the permafrost is just disappearing now. So they will have to redo that soon.

Amy Martin All across the Arctic, communities are spending huge amounts of time and money trying to figure out how to live in this new reality, where the ground is truly shifting beneath their feet. It’s not just homes and other buildings – thawing permafrost affects all aspects of infrastructure – water mains, sewage drains, even the graves of human beings, laid to rest. So we should care about permafrost if we care about Arctic people being able to meet their basic needs. But it doesn’t end there. Gesche says permafrost is actually helping all of us meet our needs, no matter where we live. It’s providing a globally important service: thousands of years of carbon storage, free of charge.

Gesche Blume-Werry So the permafrost that we have here was formed probably in the, during the last Ice Age, so eleven thousand years or so ago. And that material in them is that old. Like, it is made up out of plant material from plants that used to grow at that time.

Amy Martin If you didn’t know what you were looking for, you wouldn’t necessarily know there was permafrost here. I’m just looking at tall green grass and little clutches of white Arctic cotton flower, blowing in the breeze. But if we were to drill down into the soil below our feet, and cut a chunk of the permafrost out, we would be holding an actual 11,000-year-old block of dirt, containing remnants of whatever was alive here at that time.

Gesche Blume-Werry Mainly dead plants. Sometimes also maybe the occasional dead animal, like a mammoth.

Amy Martin Not fossilized bones, or petrified wood. The actual stuff, in its original state. And this is weird. Usually, organic material this old would be completely decomposed after so long.

So, why isn’t it, here?

Gesche Blume-Werry Like, if you imagine you have your food standing like in the kitchen during the summer, it will go bad really quickly. And then if you take food and put it in the fridge it takes obviously a lot longer. And if you put it in the freezer, I mean you can, you can have it there for years and years and it doesn’t go bad. And the same thing happens here.

Amy Martin We’ve put our carbon in the freezer.

Gesche Blume-Werry Yeah, we have. And now, we are unfortunately kind of taking the plug out of the freezer and it’s starting to thaw.


Gesche Blume-Werry So that’s why a lot of people are interested in working with permafrost because we think there is so much of this carbon that has been stored away, put away like in this freezer for years and years and years and years, and now within a very, very small period of time, like within a few decades, we actually have this thawing of the permafrost and this releasing of carbon.

Amy Martin And then so once permafrost starts to truly thaw, then, then carbon just kind of comes, like, how does the carbon get from down there to up into the atmosphere?

Gesche Blume-Werry Because microbes are eating it. And they are respiring, so they are breathing, basically. And then they emit carbon.

Amy Martin So it’s microbe breath that we have to worry about.

Gesche Blume-Werry Yeah, basically.

Amy Martin Damn microbes!

Gesche Blume-Werry And cow farts. I think they are the worst.

Amy Martin Microbes! They are the third party in this drama. When living things die, microbes are the ones that do the work of breaking things down. They basically operate tiny little chemistry labs that unlock the carbon in a blade of grass or the horn of a bison. And like Gesche said, when they do that, they respire carbon dioxide. I’m going to continue to call it microbe breath, even though most of these tiny little organisms don’t actually have mouths, let alone lungs. The point is, their work puts more carbon dioxide into the atmosphere. Freezing slows them down, thawing speeds them back up. And Gesche says in many parts of the Arctic, the permafrost is right on the cusp of that pivot point between frozen and thawed.

Gesche Blume-Werry If you have a warming of one degree that makes all the difference in the world because it gets from frozen to thawed. And that is something that us scientists are really worried about, because there are many thresholds that you might cross there.

Amy Martin Thank you for referencing my show.

Amy Martin Sorry to be so self-referential here, but this concept of thresholds comes up over and over when you talk to scientists in the Arctic. And that’s just because of the nature of how things freeze and thaw. When something is really, really cold, a temperature change of one or two degrees might not have an obvious effect. But when something is teetering between a frozen and an unfrozen state, a one degree temperature change can trigger a radical transformation. It can flip permafrost soil from being something that stores carbon to something that emits it.

Gesche Blume-Werry If these numbers just change a little bit, then it can have really dramatic consequences.

Amy Martin And that’s because as soon as the soil thaws out, microbes are ready to go to town, breaking down that frozen dead stuff and breathing out planet-warming gases. But how much does this microbe breath really matter? Like, how much carbon is there in Arctic soil?

Joachim Jansen The amount of the amount of carbon that’s stored in here, it’s twice the amount that we have in the atmosphere. And so if that will all be released into the atmosphere, that would mean a huge climatic change for sure.

Amy Martin This is Joachim Jansen, he’s from the Netherlands, and like Gesche, he’s studying permafrost here in northern Sweden.

Amy Martin When you say the amount of carbon we have stored here is twice what’s in the atmosphere, you mean the amount of carbon we have in the Arctic?

Joachim Jansen Yeah. Just in Arctic permafrost –

Amy Martin Just in Arctic permafrost?

Joachim Jansen Permafrost soils. Yeah.

Amy Martin Whoa. That’s twice what’s in the atmosphere right now.

Joachim Jansen Yeah. Yeah.

Amy Martin Wow. OK.

Amy Martin This is a statistic worth remembering, so I'm going to say it again another way. Take all the carbon currently floating around in the atmosphere, and put it in one bucket. Then scoop up all of the carbon currently frozen in Arctic permafrost, and it would fill two buckets of the same size. Atmospheric carbon–


Permafrost carbon–


Amy Martin I’m using that alarming sound effect because this is alarming.

Usually, when we talk about carbon emissions, we’re picturing exhaust from tailpipes or soot spewing out of smokestacks. But here, in this beautiful little Swedish meadow, there’s all kinds of carbon waiting to be released. In fact, our human-caused emissions, big as they are, would be dwarfed by all of the carbon stored in Arctic soil.

Gesche Blume-Werry We might tip the scales of these really large exchanges that have, as such, nothing to do with us. But because they are so large, small increases in them can have a really big effect.

Amy Martin And there’s more. This giant reservoir of greenhouse gases stored in Arctic soils, it hasn’t yet been factored into the models that we’re using to set global climate policy. Meaning, the Paris Agreement. Carbon emissions from thawing permafrost soil aren’t factored into that. Which means, the goals set in that agreement may not go nearly far enough. Like, we may be aiming to reduce our carbon emissions by X percent, but once we factor in the carbon coming out of the permafrost, it may turn out that we need to reduce our emissions by X percent times ten, or five, or twenty.

So why aren’t permafrost emissions part of the Paris Agreement? To answer that question, we’re going to take a boat ride. Right after this short break.



Amy Martin Welcome back to Threshold, I’m Amy Martin, and I’m out on a lake with three scientists, just down the road from the meadow where I was talking with Gesche. It’s a lovely summer day, there are flocks of birds circling around us in the sky and I’m just sitting in the middle of a row boat like a tourist in Venice.

Amy Martin Who knew that climate change research could be so much fun?

Mathilda Nyzell We have so much fun in the boat, when me and Jenny go out.

Amy Martin That’s Mathilda Nyzell. She and Jenny Gåling trade off doing the rowing. They’re master’s students at Stockholm University, working as field assistants on this project which is led by Joachim Jansen, who’s getting his PhD.

So, a quick reminder of what we know so far: permafrost is frozen soil, it’s storing a lot of carbon – twice as much as what is currently in the atmosphere – and, as we warm the planet, we risk setting off a sort of chain reaction, in which our emissions cause these natural emissions to accelerate, which leads to yet more warming, which leads to more emissions, and on and on.

And, we learned permafrost emissions aren’t yet included in the Paris Agreement, which is an international effort to limit global temperature rise to less than two degrees celsius over pre-industrial levels. Almost every country in the world, other than the United States, intends to honor that agreement. And although many believe it doesn’t go nearly far enough, it has been heralded as a breakthrough in global climate policy.

But carbon emissions from frozen soils have not been factored into it. So the question is: why not? To answer that, we’re going to try to wrap our heads around this one project, on this one lake, in this one country. Here’s Joachim, explaining what this project is all about.

Joachim Jansen We are looking at the methane gas bubbling from the lake sediment into the atmosphere.

Amy Martin Methane is just another carbon-based gas produced by microbes. It’s actually a much more potent brand of microbe breath than carbon dioxide; it does a much better job of trapping heat in the atmosphere for a short time, but then decays into carbon dioxide after a decade or two. The microbes that produce methane are called methanogens.

Joachim Jansen Right, so the reason we have a lot of methane here is because this is a very organic rich area. In the lake we have a lot of organics washing in from the land and this is the material that the methanogens, the bacteria, they need.

Amy Martin So, in this ménage à trois between carbon, microbes, and frozen soil, methanogens are the microbes that show up in wet places. We’re talking about inside cow stomachs, and in sediments at the bottoms of lakes. Since the thawing of permafrost is making the Arctic wetter, that means more habitat for methanogens, which means more methane – more of this powerful climate-warming gas. But, how much more? That’s what this team is trying to figure out. Their mission is to capture and measure this particular brand of microbe breath.

Joachim Jansen And in order to do that we have a whole number, 40 in total, of these inverted funnels, and they float on the water.

Amy Martin Picture a big funnel, like you would use if you needed to pour gas into your car from a can. Mathilda rows us up close to one of them, turned upside down, floating in the lake. It has a big syringe fitted onto the skinny end, which in this case is the top. These little contraptions look pretty home-made because they are.

Joachim Jansen The way we make them float is by using pool noodles. The things you would use in the swimming pool?

Amy Martin [LAUGHS]

Joachim Jansen So we got a whole box of those, it’s kind of weird when you buy them.

Amy Martin So, you take your plastic funnel, turn it upside down, wrap a piece of pool noodle around the wide part, and put a plastic syringe on the top, and you’ve got yourself a little trap, designed to capture–

Mathilda Nyzell any ebullition from the bottom sediment.

Amy Martin Any what from the...?

Mathilda Nyzell Ah, bubbles, basically. Ebullition.

Amy Martin Ebulation.

Mathilda Nyzell Ebullition.

Amy Martin I love it. When scientists want to say bubbles, it’s not a bubble, it’s an ebulation.

Amy Martin I was saying it wrong, actually. It’s ebullition, not ebulation. But anyway, bubbles. Microbe breath.

Joachim Jansen The methane bubble gets in, and we have a tap at the top that we can open up and then we can sample the gas with a syringe, and then we take that into the lab and then we measure the methane concentration.

Amy Martin Mathilda expertly rows us up to another trap, and Joachim reaches over the side of the boat with a syringe in his hand.

Amy Martin So he’s pulling out the gas. What’d you find there?

Joachim Jansen So, we emptied the bubble trap of gas. And we had about 7 milliliters of gas. And it used to be in the lake sediment where it formed a bubble, and that bubble traveled through the water into our trap, and now it’s in the syringe.

Amy Martin They’ve likely captured a mixture of gases.

Joachim Jansen Most of which will likely be methane, but we’re not sure, so we take these to the lab, and then we measure the actual methane concentration.

Amy Martin They have forty of these bubble traps on this lake, a bunch more on another lake, and they check all of these traps multiple times a week, all summer long. This is the nitty-gritty of science: making the instruments you need, collecting your data bit by tiny bit, carefully recording your findings. And this is all just to understand how much methane is coming off this one small area. This year. Under these particular conditions. And Joachim says the more we learn about communities of microbes, the more we realize how complex they are.

Joachim Jansen Those communities will change. Like it will be above water at one point and then it thaws out, and then suddenly will be underwater and then different microbes will be there that can eat different types of carbon. And then the water starts to move and it starts to transport carbon away. And so it’s all very complex. It’s a complex system.

Amy Martin And he’s just talking about the complexity here, at this study site. Groups of scientists are at work around the Arctic, studying sites that are wetter, drier, colder, or warmer, with more or less vegetation.

Joachim Jansen And so what makes this complicated is the heterogeneity of it so the diversity of landscapes and microbial life that we’re dealing with.

Amy Martin So, how old is the carbon these microbes are eating? Like, are they chomping on dead plants from 200 years ago, or 20,000 years ago? And how quickly are they eating it? And once we understand what’s going on in this one particular study site – which is clearly no small task in itself – how do we combine that knowledge with information from other sites to really accurately predict carbon emissions from thawing permafrost overall? The answer to all of these questions is the same. We don’t really know yet.

Joachim Jansen The reason we worry is because we don’t know, I think. And that’s why we’re here and that’s why we are measuring.

Amy Martin This is why we haven’t included carbon emissions from frozen soil in the Paris Agreement: calculating this stuff is really complex. And, we’ve never warmed the planet up like we’re doing now. The last time there was this much carbon in the atmosphere was before humans walked the Earth. So, at least from our species’ perspective, we’re in what’s called a “no analog” situation.

Joachim Jansen There’s like this big machine that we’re operating that we don’t know anything about.

Amy Martin Scientists are working feverishly all around the Arctic, trying to figure all of these things out, so we can start to update our models and our climate policies.

Joachim Jansen I think the scary part is that we don’t know what an extra four degrees of warming will do to this huge amount of carbon that’s stored here in the permafrost.

Amy Martin But, mixed in with all of these unknowns, there are some things we do definitely understand. I try to repeat back what I’ve learned to Joachim to see if I’ve got my facts straight.

Amy Martin In really broad terms, there’s two ways to heat up the planet. There’s, there’s things that humans do and there’s things that the Earth naturally does on its own.

Joachim Jansen Yep.

Amy Martin And these two things do not operate in isolation from one another. The way that the humans are heating up the planet can affect the way that natural systems work. Is that right?

Joachim Jansen That’s exactly right, yeah. So by warming up the planet, and especially the Arctic, we accelerate natural processes that are already naturally release greenhouse gases into the atmosphere. That’s a process that’s already happening, but by further warming the Arctic climate that process is going to accelerate.

Amy Martin We don’t know how close we are to a massive release of carbon from frozen Arctic soils. But we do know that every bit of carbon we emit into the atmosphere gets us closer to that point. And we also know that we don’t get a second chance at this. Once our emissions trigger this much larger release of carbon, we’ve put ourselves at the mercy of processes that will dramatically reshape the Earth’s climate, and our own civilizations. That’s why Joachim believes caution is in order.

Joachim Jansen There’s a knob that we turn on that big Arctic permafrost machine that we don’t know what it does. And until we actually figure out what it does, it may be a good idea to stop turning the knob.

Amy Martin I asked him if he thought it was still worth it to try to stop turning the knob? Like, is it already too late? Has the damage been done?

Joachim Jansen No, we have an ability to say stop. I mean, of course we do. We have choices. And I think especially in the western world, in the rich world, we have, we choices, and therefore we have a responsibility. And one of the ways is this is to try and understand this experiment better. And that’s my part, that’s what we do here. And the other part is acting on what we already know, which is stop putting so much greenhouse gases in the atmosphere. Yeah, I think we have a responsibility, and I think we can act. Absolutely.

Gesche Blume-Werry It’s not about saving the polar bear.

Amy Martin Gesche Blume-Werry.

Gesche Blume-Werry I think a lot of people when they think about climate change they’re like, yeah, you know some plants will disappear, and the polar bear, yeah, it’s cute. But it’s also about like us surviving as a species because if it gets much warmer the way, like, that we have evolved with our agriculture and how we, like, the food we eat and where we live it’s just not adapted to that.

Amy Martin Yeah.

Gesche Blume-Werry Yeah. It’s just not.

Amy Martin I mean, it sounds really scary. How scared are you?

Gesche Blume-Werry Sometimes, I get really scared…If I really, really think about it I get freaked out, seriously freaked out, but then I’m like OK. But you know you also have to, you cannot spend your life in being freaked out.

Amy Martin Getting scared as we learn about this stuff is totally normal. It’s what we do with that fear that matters.

Gesche Blume-Werry It never helps to put your head in the sand, right? I mean it never helps to just, to just stop functioning because you are too scared of something. I mean that’s a very bad strategy in general, so I don’t think we should do that.

Amy Martin When we hear scientists talk about one or two or three degrees of warming, it might not sound like a big deal. But the additional carbon that we’re adding to the atmosphere is like kindling that could ignite a much more powerful fire. We’re sparking a dangerously heated love triangle between carbon, permafrost, and microbes.

They’ve got their own thing going on: they very literally have their own chemistry. And if we don’t respect that, there will be consequences. We have to figure out how to place some limits on ourselves, or a network of microscopic beings is ready to impose the limits on us. It’s humbling. Maybe that’s why we’re having such a hard time wrapping our heads around the realities of climate change.

Amy Martin Do you think we can do it? Like do you do you think that in 5,000 years we’re going to look back and be like that was the point when humans started their path toward extinction? Or do you think we’re going to look back and be like that was the point where we started to grow up and we shifted into a different kind of way of living.

Gesche Blume-Werry I really really really really wish that at the point where we shifted. I don’t know. Yeah, I really hope so.


Amy Martin This season of Threshold was produced in partnership with Montana Public Radio and PRI’s The World. And with support from the Pulitzer Center on Crisis Reporting, the Park Foundation, and to you, our listeners. We want to keep in touch with you! Join our mailing list at

Threshold is created by Nick Mott, Rachel Cramer, Cheryl Skibicki and me, Amy Martin, with help from Frank Allen, Jackson Barnett, Josh Burnham, Maxine Speier, Michael Connor, Matt Herlihy, Nora Saks, Rachel Klein, Rosie Costain, Zach Wilson and Zoë Rom. Special thanks to Tom Evans,Tom Douglas, Cindy Gilbert, Michael Gundale, Keith Larson, Sylvain Monteux, Michael SanClements, Kevin Schaefer, Sarah Strand, and Hannah Rosenzweig. Our music is by Travis Yost.

And in our next episode…

John Hoffecker The sun goes down, and it stays down.

Amy Martin Why did humans ever come to live in the Arctic in the first place?

John Hoffecker It’s all dark. For months.

Amy Martin That’s next time on Threshold.