Ice Sheet Time Machine

Summary

Podcast Summary: Unexplainable – “Ice Sheet Time Machine”

Episode Date: August 27, 2025
Host: Vox (Bird Pinkerton, with guests Paul Bierman and Richard Alley)
Topic: The story of Camp Century, a secret Cold War-era US military base built under the Greenland ice sheet, and how its ice core and sub-ice samples have fundamentally changed our understanding of Earth’s climate history and its future.

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Main Theme / Purpose

This episode explores the extraordinary science legacy of Camp Century – a 1950s nuclear-powered US Army base dug into the remote Greenland ice sheet. What began as a piece of Cold War strategic infrastructure became a portal into the past: by drilling a mile-long core of ancient ice (and sediment from underneath), scientists unlocked vital new clues about abrupt climate changes, how sensitive Greenland’s ice is to warming, and what that might mean for global sea levels.

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Key Discussion Points & Insights

1. The Science Fiction Reality of Camp Century

• [01:21–03:19] Bird Pinkerton introduces Camp Century: a secret research base built beneath Greenland’s ice during the Cold War, complete with city-like tunnels. Geoscientist Paul Bierman describes the scene:

  “There was one long street…about 1,000 feet long…and then tunnels branching off the sides…” (Paul Bierman, 02:12)

• The US military’s motives were twofold: defense against possible Russian attacks (imagining Greenland as the “gateway” between the USSR and North America) and a wish to understand how ice and snow behave for potential troop movement—or, more ominously, missile deployment.

2. Unlocking Ancient Climate Clues

• [03:34–05:47] Early on, the scientific value became clear. Each year’s snowfall traps gases, dust, and even volcanic fallout—layer upon layer, building a chronological record.

  “Each layer of snow turned into ice was like a page in a big record of Earth’s history.” (Bird Pinkerton, 04:38)

• The goal: to drill a “mile-long core” from the ice, potentially revealing thousands or even hundreds of thousands of years of data.

3. Drilling Challenges – Failure and Triumph

• [05:47–07:43] Drilling through a mile of ice is far from simple. Early attempts (melting through) ran into endless logistical headaches—broken cables, drill heads lost deep in the ice. One oral history captures the repeated heartbreak:

  “So…at 750ft, we lose a part of the drill, and that was the end of that hole. So it was just one heartbreak after another.” (Oral history, quoted by narrator, 06:31)

• Eventually, switching to a grinding method, the team succeeded. In 1966, just as Camp Century was abandoned, they reached the base of the ice sheet—and pulled up not just ice, but the sediment below it.

4. Rewriting Climate History

• [07:51–09:52] The resulting samples revolutionized climate science.

  “The ice was revolutionary. A fellow named Willy Dansgaard really pioneered the study of the water molecules in the ice…could determine…temperatures in the past.” (Paul Bierman, 08:11)

• Findings overturned the assumption that Earth’s climate changed only gradually. Instead:

  “Temperatures could change…pretty abruptly.” (Paul Bierman, 08:48)

• Gas bubbles revealed the composition of ancient atmospheres, and volcanic layers told of past eruptions. This research provided foundational understanding of how greenhouse gases relate to warming.

5. Moon Rocks vs. Greenland Mud: The Mystery of the Missing Sediment

• [09:55–11:34] While ice samples were fastidiously studied, the soil collected from beneath Camp Century was almost ignored – “we have significantly less material from underneath Greenland’s ice sheet than we do rocks from the moon.” (Paul Bierman, 10:18)
• Over decades, the bottom-of-core sediments simply disappeared into bureaucratic limbo—lost between storage facilities, with rumors of them languishing in Denmark.

  “Most people…said, ah, those cores are gone. That’s…they’re just not around anymore.” (Paul Bierman, 11:19)

6. The Turn to Rocks – and What They Reveal

• [14:18–20:34] Bird Pinkerton and glaciologist Richard Alley discuss how, since the 1990s, attention (finally) shifted to sediments under the ice. High-tech methods let scientists measure cosmic-ray “zaps”—which showed that, not so long ago (geologically speaking), even thick central Greenland was ice-free.

  “…technology…showed researchers that, yes, the rocks from under the ice did, in fact, seem to have been zapped. And fairly recently, too, or like, geologically recently.” (Bird Pinkerton, 17:21)

• This finding drastically shrinks the range of temperatures/conditions needed to melt Greenland’s massive ice cap—and raises the stakes for current climate change.

  “Greenland lost most of its ice…which means it is possible that temperatures right now are either hot enough or almost hot enough to melt most of the ice on Greenland if given enough time.” (Bird Pinkerton, 18:51)

7. Rediscovery – The Camp Century Core Returns

• [21:40–23:58] As Paul Bierman tells it, this all changed when missing core samples were unexpectedly found in a Danish freezer outside Copenhagen:

  “…waves at, like, three of us and he says, come over and look at this...in the corner was this cardboard box filled with glass cookie jars filled with brown lumps of frozen soil. So that is the first time I saw the Camp Century Core.” (Paul Bierman, 22:19)

• The scientists, giddy, received samples in Vermont. When thawed, the mud filled the lab with the stench of diesel and solvents (used in drilling)—but inside were floating twigs, moss, leaves. Fossil clues of an ice-free Greenland ecosystem, with precisely datable relics.

8. From Science to Urgency: The Value of Information

• [26:29–28:30] The new fossil evidence enables scientists to better date and understand when and how rapidly these regions became ice-free, tightening projections on how quickly (and under what temperature scenarios) Greenland might melt today.
• Richard Alley drives home the practical stakes:

  “If we have the sea level rise wrong…if it rises higher than [cities are] building for...we have Katrinas, we have cities flooding and lives lost…So the value of information is so huge.” (Richard Alley, 27:33)

9. Camp Century’s Dual Legacy

• [28:30–End] Camp Century left behind not just scientific treasures but a dangerous toxic mess—sewage, diesel, even nuclear waste. The assumption was that all this would remain safely locked in ice. With Greenland’s ice now melting, the reckoning is coming.
• For Bird and her guests, Camp Century is both a cautionary tale and a source of hope:

  “…that we as a species are really good at doing impossible seeming things, that we can figure out how to carve a city into the ice or drill a hole a mile down into it. And so hopefully we can also figure out how to clean up after ourselves.” (Bird Pinkerton, 29:18)

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Notable Quotes & Memorable Moments

| Timestamp | Speaker | Quote | |:-------------:|:------------|:----------| | 02:12 | Paul Bierman | “There was one long street…about 1,000 feet long…and then tunnels branching off the sides.”| | 04:38 | Bird Pinkerton | “Each layer of snow turned into ice was like a page in a big record of Earth’s history.” | | 06:31 | Herb Uida (oral history, narrator) | “So…at 750ft, we lose a part of the drill, and that was the end of that hole. So it was just one heartbreak after another.” | | 08:11 | Paul Bierman | “The ice was revolutionary. A fellow named Willy Dansgaard really pioneered the study of the water molecules in the ice…could determine…temperatures in the past.” | | 08:48 | Paul Bierman | “Temperatures could change…pretty abruptly.” | | 10:18 | Paul Bierman | “We have significantly less material from underneath Greenland’s ice sheet than we do rocks from the moon.” | | 11:19 | Paul Bierman | “Most people…the people I talked to…said, ah, those cores are gone.” | | 17:21 | Bird Pinkerton | “…technology…showed researchers that, yes, the rocks from under the ice did, in fact, seem to have been zapped. And fairly recently, too, or like, geologically recently.” | | 18:51 | Bird Pinkerton | “Greenland lost most of its ice…which means it is possible that temperatures right now are either hot enough or almost hot enough to melt most of the ice on Greenland if given enough time.” | | 22:19 | Paul Bierman | “…waves at, like, three of us and he says, come over and look at this...in the corner was this cardboard box filled with glass cookie jars filled with brown lumps of frozen soil. So that is the first time I saw the Camp Century Core.” | | 27:33 | Richard Alley | “If we have the sea level rise wrong…if it rises higher than [cities are] building for...we have Katrinas, we have cities flooding and lives lost…So the value of information is so huge.” | | 29:18 | Bird Pinkerton | “…that we as a species are really good at doing impossible seeming things...hopefully we can also figure out how to clean up after ourselves.” |

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Timeline of Important Segments

• 01:21–03:19 — Setting the scene: Cold War, Camp Century's secret city beneath the ice.
• 03:34–05:47 — The promise of ice cores and what scientists hoped to learn about Earth's past.
• 05:47–07:43 — Drama and setbacks in drilling; ultimate success in 1966.
• 07:51–09:52 — Ice core research revolutionizes understanding of abrupt climate change.
• 09:55–11:34 — The mystery of the missing Camp Century bottom sediments.
• 14:18–20:34 — Recent science: sediment reveals Greenland’s last ice-free period may have been geologically recent and sensitive to small temperature changes.
• 21:40–23:58 — Rediscovery of the missing core; fossil evidence found.
• 26:29–28:30 — From discovery to impact: projections of sea-level rise and their stakes for policy, city planning.
• 28:30–End — The messy legacy of Camp Century, and hope for human ingenuity to clean up and learn from the past.

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Tone and Style

The episode features the characteristic Unexplainable blend of curiosity, wonder, and a hint of anxiety in the face of sprawling climate questions. Bird Pinkerton’s narrative is informed and warm, the scientists she interviews are enthusiastic—sometimes nerdily giddy, sometimes somber—about the knowledge and risks embedded in ancient ice and mud. Powerful metaphors (“a city buried in the ice”; “pages in Earth’s diary”; “rarer than moon rocks”) and moments of scientific delight (“fossils in here!”) keep the listener engaged.

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TL;DR

Camp Century’s mile-long ice core (and long-lost mud) have reshaped what we know about how rapidly—and perhaps how soon—Greenland’s mighty ice sheet could melt, driving catastrophic sea-level rise. The story blends Cold War drama, scientific adventure, accidental miracles, and a sobering reminder: Understanding our planet’s past may be the best hope for foreseeing—and hopefully averting—disaster in its future.

Transcript

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[Paul Bierman]

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[Narrator]

On the top of the world, below the surface of a giant ice cap, a city is buried.

[Bird Pinkerton]

In the late 1950s, the US army kicked off a project that sounds like something out of science fiction.

[Narrator]

As part of man's continuing efforts to master the secrets of survival in the Arctic, the United States army has established an unprecedented nuclear powered Arctic research center. This is the story of Camp Century, the City under ice.

[Bird Pinkerton]

Camp Century was a research base carved into the Greenland ice sheet, about 800 miles from the North Pole. A geoscientist named Paul Bierman told me all about it.

[Paul Bierman]

The layout was very much like a city grid.

[Narrator]

The basic concept was simple.

[Paul Bierman]

There was one long street that was about 1,000ft long down the middle, and then tunnels branching off the sides, a.

[Narrator]

Series of lateral trenches housing complete research, laboratory and test facilities.

[Paul Bierman]

Some of the tunnels held the mess.

[Narrator]

Hall, everything from steak to fruit salad.

[Paul Bierman]

Some of those tunnels held the latrines.

[Narrator]

Here there are showers for all.

[Paul Bierman]

Some of those tunnels held barracks.

[Narrator]

It also has a small chapel for regular religious services.

[Paul Bierman]

I think you have to imagine yourself dressed in clothing from the early 1950s. And you have to imagine the magazine ads and you have to imagine these sort of frightening movie titles and posters of the communists coming to take over America. That's, that's the milieu. That's the, that's the cultural setting in which Camp Century is designed and thought.

[Bird Pinkerton]

About the US was about a decade into the Cold War at that point, and they were worried.

[Paul Bierman]

They were worried about the Russians attacking North America, right? And so Greenland is the gateway from the Soviet Union to North America.

[Bird Pinkerton]

They wanted to understand more about the snow and the ice so they could move materials and troops across it or even potentially hide missiles in it. And so that's a big reason why they built this elaborate research base to unlock the ice's secrets.

[Paul Bierman]

So many of their studies were basic science in the behavior of snow. And we still use what the army learned back 50, 60 years ago to understand how ice sheets move today.

[Bird Pinkerton]

But they had another motivation for digging into the ice, because Even in the 1950s, people thought the climate might be warming.

[Paul Bierman]

And there were people even back then who thought, could this be human induced climate change?

[Bird Pinkerton]

There were other explanations put forward, like sunspots and orbital wobbles. But the question kicked off a quest, a quest that hold up answers we are still learning from to this day. This project to drill down and then pull up a long tube of ice. Scientists call it a core, something that's.

[Paul Bierman]

4, 5, 6 inches in diameter, and then stretches the depth of the ice sheet. And at Camp Sentry, the depth of that ice sheet is almost a mile.

[Bird Pinkerton]

The scientists wanted this mile long core of ice because they realized that as snow fell and piled up in layers year after year on this ice sheet, it trapped little traces of the world inside it. Everything from atmospheric gases to volcanic fallout. So each layer of snow turned into ice was like a page in a big record of Earth's history.

[Paul Bierman]

The record dating back at least thousands of years. They actually didn't know how far that record went. And the debates in the sort of formal and very informal literature are fascinating. There's some popular science articles that say, wow, this ice could be thousands of years old. Wouldn't that be amazing?

[Bird Pinkerton]

And the scientists were also curious about what was under the ice sheet.

[Paul Bierman]

Will there be explosive packets of gas down there that have accumulated through time? Will there be water? Will it be frozen? It was the equivalent of landing on the moon at that time.

[Bird Pinkerton]

Unfortunately, it turns out that drilling all the way through a mile of ice and then pulling it up section by section or like cylinder by cylinder is not all that simple.

[Paul Bierman]

Their first idea was, well, why don't we just melt through it? And the description would be like melting your way through a barrel of butter. That sounds easy, right? But it turns out it wasn't so easy because you're melting your way through the ice. Okay, that works. Until you figure out how am I going to get rid of the water and how am I going to keep that hole open so it doesn't collapse? And what if the cable I have my drill on breaks, and what if I get the drill head stuck?

[Bird Pinkerton]

The drill heads did, in fact, get stuck. In an oral history years later, one of the researchers, this guy named Herb Uida, talked about how the drill got stuck several hundred feet in the ice, which then forced them to start the process all over again.

[Narrator]

By the way, each time we couldn't retrieve or maintain the hole. Well, it was a major operation because you had to move the winch and everything and start a new hole. And remember, we were down in this trench there and our space was sort of limited, so it was a major concern. So we did start another hole, and lo and behold, at 750ft, we lose a part of the drill, and that was the end of that hole. So it was just one heartbreak after another. For those couple of years, they were.

[Bird Pinkerton]

Able to bring up material, but they weren't able to get to the bottom of the ice sheet. Years went by without success.

[Narrator]

Finally I said, you know, we've got to start considering something else.

[Bird Pinkerton]

They wound up pivoting to a different drilling technique, one that involved grinding instead of melting.

[Narrator]

Lo and behold, it. Well, that was the struggle getting going. But we finally got it going, and it worked like a charm.

[Bird Pinkerton]

In 1966, as Camp Century was winding down its operations, the researchers did finally hit the bottom of the ice sheet. And they didn't stop there. They were also able to drill into the sediments under the ice sheet and pull up some of that material, too.

[Narrator]

Probably the most satisfying moment of my life, of my career, of my career.

[Bird Pinkerton]

It turned out that the ice from this core held not just a record of the last couple thousand years, but instead a record of around 100,000 years of Earth's climate history. And that record helped rewrite our understanding of both our past and our future.

[Paul Bierman]

The ice was revolutionary. A fellow named Willy Dansgaard really pioneered the study of the water molecules in the ice and how those water molecules could be used to tell about the history of climate. And so by analyzing the water molecules, Willie and his group could determine with reasonable accuracy the temperatures in the past.

[Bird Pinkerton]

Willy Dansgaard's work on the ice actually challenged some fundamental things people had assumed about Earth's climate. Scientists had sort of thought that Earth's temperature shifted slowly and gradually, but this ice suggested no temperatures could change.

[Paul Bierman]

Pretty abruptly, it opened up this window to the past that now dozens and dozens of ice cores have exploited to understand climate around the world.

[Bird Pinkerton]

Dansgaard was not the only scientist who analyzed this ice core from Camp Century. In the years and decades after it came out of the ice sheet, many scientists studied samples of this ice and wrote papers about it.

[Paul Bierman]

And they learned all kinds of things. They learned when volcanoes erupted because the dust and the acid from those volcanoes would land on the snow in Greenland and become ice. They learned about changes in the amount of sea salt coming off the ocean. They learned about changes in climate over time.

[Bird Pinkerton]

Researchers figured out how to analyze little gas bubbles trapped in the ice, which, which are kind of like bubbles of ancient atmosphere. And that meant they could see how much of any given gas had been present when things were hotter or colder on Earth. And so this ice, along with other ice cores, helps scientists show how greenhouse gases in the atmosphere can lead to warming.

[Paul Bierman]

All to say, this core just keeps on giving.

[Bird Pinkerton]

This long tube of ice helped us learn a lot. But even though all these scientists were doing all this work on the ice itself, they were kind of ignoring another potential source of the stuff that came up from under the ice.

[Paul Bierman]

Until about five years ago, there were three publications on the frozen soil.

[Bird Pinkerton]

As Paul puts it, we have significantly less material from underneath Greenland's ice sheet than we do rocks from the moon. So this frozen soil should be pretty precious.

[Paul Bierman]

And yet I think the focus of the community was almost laser on the ice and not on the stuff beneath it.

[Bird Pinkerton]

In fact, there was so little attention being paid to the soil from underneath Camp Century that it somehow kind of disappeared.

[Paul Bierman]

There's a mystery around this that many people have taken to their graves and we will probably never know exactly what happened.

[Bird Pinkerton]

But basically over the years, the ice cores were moved to different storage facilities. So first one in Buffalo, and then in the 90s to a facility in Colorado.

[Paul Bierman]

And soon after, people noticed that the bottom of Camp Century and the bottom of an ice core called Bird Station from Antarctica never made it to Colorado.

[Bird Pinkerton]

Paul spoke to some people who thought they'd ended up in Denmark maybe, but nobody really seemed to know.

[Paul Bierman]

Most people, the people I talked to when I was being trained and I occasionally thought about Camp Century in the years after, and I asked them, they said, ah, those cores are gone. That's they're just not around anymore.

[Bird Pinkerton]

Losing track of any sample is a shame. But in retrospect, this sample in particular had a lot to tell us. More on that after the break.

[Paul Bierman]

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[Narrator]

We don't know anything about a core.

[Paul Bierman]

That's it. You want some of this?

[Narrator]

Where's the core?

[Paul Bierman]

Where's the core?

[Bird Pinkerton]

Where's the core? I wish I loved anything as much as Richard Alley loves ice.

[Richard Alley]

It's just gloriously beautiful. If you've ever looked at a glacier flowing down a mountain, if you've ever seen a time lapse of a glacier flowing or looked at the snowflakes that go into it, or peered down a moulin, this giant hole that the stream mills down on a mountain glacier that goes to the bottom of the ice. I mean, just the glory and the excitement.

[Bird Pinkerton]

Fortunately, Richard has had lots of opportunities to study his favorite subject. He has been studying ice as A scientist and a researcher ever since he was in undergrad in the 1970s.

[Richard Alley]

Ice started summer after freshman year.

[Bird Pinkerton]

Oh, so you know a thing or two about ice.

[Richard Alley]

Coming up on 50 years.

[Bird Pinkerton]

It was actually a great time to get into ice research. The Camp Century core had come out of the ice sheet, and that core, along with ice from Another site called Dye3, wound up raising all kinds of interesting questions about these abrupt changes in past climate.

[Richard Alley]

And when I first became an assistant professor trying to work my way towards tenure, I was fortunate enough to get involved in one of the projects that came out of camp century. And Dye3 have told us what we have to know. Let's go find out.

[Bird Pinkerton]

Finding out involved two separate drilling teams drilling two new cores in the Greenland ice. Those cores came UP in the 1990s, and the researchers on each team spent a bunch of time checking them out.

[Richard Alley]

And we find all these abrupt climate changes, and oh, my goodness, it's just wonderful, wonderful science. And duplicated across the two cores, and it's pound on the table. This is right. We got it nailed.

[Bird Pinkerton]

But this drilling also brought up some of those rarer than moon rock sediments. And these rocks did not get lost. They got some sustained research attention. Scientists wound up looking at them to see if they'd gotten zapped by cosmic rays.

[Richard Alley]

So we are, you know, getting zapped by cosmic rays. And cosmic rays occasionally cause damage, and some small fraction of cancers are probably caused by cosmic rays ripping through us in some way.

[Bird Pinkerton]

Oh, just one more thing to worry about.

[Richard Alley]

It's small. It's not, you know, there's lots and lots of bigger things to worry about in that world. But. But nonetheless, this happens.

[Bird Pinkerton]

And cosmic rays also rip through rocks and damage their atoms. Now, the effects of the zapping kind of fade over time. So scientists have found a way to basically search rocks for weird damaged atoms and see, were they out in the open recently? Like, were they close enough to the surface to get zapped?

[Richard Alley]

And when this was first measured in the 90s, it was right at the edge of what was doable.

[Bird Pinkerton]

But by the 2010s, the technology was more advanced, and it showed researchers that, yes, the rocks from under the ice did, in fact, seem to have been zapped. And fairly recently, too, or like, geologically recently. They couldn't put an exact date on it, but their research suggested that sometime in the last million or so years, this spot was ice free. Now, this was just one spot, right? But it was near the middle of the ice sheet. So that could mean that if this spot was ice Free then much of Greenland was also ice free at that time, and that would be a pretty big deal. Greenland's ice sheet is absurdly large. Like it's almost two miles deep at some points. That's a mountain of solid ice. And for a long time people thought that mountain of ice would be hard to melt or that our world would have to be hotter for that to happen. Except if you look back across this million year window, there's just no time.

[Richard Alley]

That it was lots warmer than today, but somewhere when it was a little warmer than today, or maybe just equal to today. But it stayed that way for a while. Greenland lost most of its ice, which.

[Bird Pinkerton]

Means it is possible the temperatures right now are either hot enough or almost hot enough to melt most of the ice on Greenland if given enough time. Richard told me that the notion that Greenland's ice was super hardy was already kind of on thin ice by the time this paper came out. But the paper was new evidence that Greenland's ice might be pretty sensitive to temperature changes. And look, if the ice melts, it's not like it will all melt tomorrow, right? It could take a long time. But if it does melt, it would mean a lot of sea level rise, like a lot, a lot of sea level rise, like potentially more than 20ft of sea level rise just from Greenland's ice. We talk about the huge problems that could come from 3ft of sea level rise. 20ft could mean coastal cities underwater and millions and millions of people potentially displaced.

[Richard Alley]

It is hard to deal with. It really is. This is a tension that I think all climate scientists deal with because we love doing science and we love it when we learn something new and we love it when things fit together. And you can look at the data coming out and saying, wow, wow, this is so cool. It's so exciting. It's so big. It's. Oh, bad word at all. Anyway, it's so bad.

[Bird Pinkerton]

Now. The news was already pretty bad, right? Like, even before this paper came out, some scientists put out another paper that showed that at other moments when the world was around as warm as it is now, there was a lot of ice melt at the poles. It's just that this cosmic ray zapping paper showed that the rocks beneath the ice could give us more information here, more specifics. And so Paul Bierman, our geoscientist, slash Camp century enthusiast, he's really excited to study those rocks further.

[Paul Bierman]

Since the Camp Century core came out, the focus has been on ice. And it's been on ice in Greenland. It's been on ice In Antarctica now, we've opened this large window that says we can learn a whole lot of different things if we look at the material below the ice. So this has no value judgment on looking at the ice at all. That's incredibly important. It's opened up this new pathway to say, well, okay, let's also start looking at the stuff beneath.

[Bird Pinkerton]

The problem, of course, is that we don't have a ton of stuff from beneath the ice. And some of what we did have, we lost somehow. When Paul first got interested in all this, the bottom of the Camp Century Core was still mia. Until all of a sudden, it wasn't. One day a few years ago, researchers from Denmark gathered some scientists, including Paul, and a geochemist named Jorg Schaefer, who'd been a lead researcher on the cosmic ray zapping paper, and they took them on a little field trip out to their new ice core storage facility on the outskirts of Copenhagen.

[Paul Bierman]

This is April. It's a beautiful April day in Copenhagen. It's warm, the flowers are out and all this. And we go into minus 27 Celsius wearing what was not enough clothing. I had a little. This picture of me with a little hat over my bald head and tiny little gloves for, like, skiing in the spring, and one jacket.

[Bird Pinkerton]

They walked in. The scientists they were with told them a little bit about the new facility.

[Paul Bierman]

And then he waves at, like, three of us and he says, come over and look at this and see in the corner was this cardboard box filled with glass cookie jars filled with brown lumps of frozen soil. So that is the first time I saw the Chem Century Core. And I can feel this right now. And it's the same feeling I had then, where this little shiver runs up your spine of, oh, my, what am I looking at? And the three of us, Jorg and I and a fellow named Nikolai, sat there, stood there must have been 20 minutes, shivering, holding these things and just staring at it and looking at each other like, is this real? Is this here?

[Bird Pinkerton]

It was real. One of the Danish researchers told Paul that the samples had been rediscovered when the new freezer was built. Paul and Jorg were obviously itching to start analyzing this mud, and the Danes agreed to share it.

[Paul Bierman]

And in July of that year at the University of Vermont, showed up a huge foam box filled with freezer packs and two pieces of sediment core that you could hold in your hands. They were half rounds. They'd taken the cylindrical core and they cut it down the middle, and they'd sent us half, and it was, oh, less than A pound of material.

[Bird Pinkerton]

They popped the samples in the freezer, and then the next day they took them out to photograph them.

[Paul Bierman]

We opened them up and the stench that greeted us was overwhelming. They smelled like diesel fuel because the drilling had been done in diesel fluid with dry cleaning fluid added for good measure. So we immediately put them back in the freezer. And then we thought about this, and we ended up melting them in fume hoods where they were ventilated so we didn't have to breathe this. And the next morning we came in, they were melted. I had a little time off from the students, and we started taking them apart. And the way we took them apart is because by this point, they were lumps of mud, right? The frozen. They just turned into mud. And we took that mud and we put very clean water on it, and we put it through a stack of sieves. Those are brass. Think about, like the screen on your screen door, but in different sizes, like big screens, medium screens, little screens. And we started washing them, and we kept every drop of water and every little piece of dust out of there because we didn't have much. And we had all these people who needed bits of it, and we sorted them all by their sizes, and we had bins of water all labeled, sitting in our laboratory. And we took a break and we came back, and I looked at one of the bins and there were things floating in it. And I looked at this bin, and I looked over at Drew Christ, who was a doctoral student working with me at the time, and I said, drew, there are fossils in here. And he looked at me and he let out this sort of string of expletives like, you're nuts. You've been out in the heat too long. And I said, no, I think there are fossils floating in here. And so we took a little pipette and we sucked out these little black bits and we put them on a little microscope slide. And I handed this thing to Drew, and he popped it under the scope. And there was dead silence for about 30 seconds. And then this scream, more expletives and a lot of joy. And we were, all, the three of us who were in there, an undergraduate was with us, kept looking down the scope, and there were twigs and there were leaves and there were little bits of moss, and all those little floating things turned out to be fossil material. And we had no clue how old it was. But it looks like if you went. If you ever been swimming in a mucky pond, and you know, you. You pull your feet back up out of that Mucky pond bottom, and there's little bits of leaves and twigs on your feet. That's exactly what this looked like. So we had found a frozen ecosystem, and it turns out now there's soil fungus in there, there's bugs, they're little midges. There's, oh, there's dozens of different forms of life.

[Bird Pinkerton]

This was clear, hold a twig in your hands type evidence that this spot near the edge of Greenland was once ice free. And this mud and these fossils, they gave Paul and his fellow researchers a lot of information. They were able to put precise dates on them, which showed them when this spot was ice free, for example. And that gives them more precise information about what conditions on Earth were like at the time of this melting. There's still a lot more to be learned about how sensitive Greenland's ice is. But just recently, more projects pulled up more ice and mud from the Greenland ice sheet. So people are investigating these questions further. Basically, we have come a long way from the days when scientists would just let soil from under the ice sheet languish, kind of undervalued, as Richard Alley puts it. Engineers have come up with plans to protect our cities from sea level rise. And they're looking at potential costs in the, in the billions or even the hundreds of billions.

[Richard Alley]

And if we have the sea level rise wrong, if it doesn't rise as much as they build for, they're wasting money building and they're losing ecosystem services and they're losing recreational services. If it rises higher than they're building for and they don't respond really fast, we have Katrinas, we have cities flooding and lives lost and properties, and, oh, it's horrible. And so the value of information on this is so huge. If somebody said, let's spend 1% of the cost of defending three cities on getting this right, we wouldn't know what to do with that much money. We don't have the people because we haven't been able to advise the students and bring them along. So this is a place where the value of information is just immense and there's a lot to do.

[Bird Pinkerton]

When the US army abandoned Camp Century in the 1960s, they didn't really clean up after themselves. They left behind tens of thousands of gallons of sewage and diesel fuel and even nuclear waste from the small reactor that they brought in to power their city. The assumption was that all that waste would just stay trapped in the ice for the foreseeable future, buried under the snow. Now, as Greenland melts, we're realizing that that's probably not the case. And so in some ways, Chem Century feels to me like a representation of both my frustrations and my hopes when it comes to the future. On the one hand, it is very frustrating to me that researchers went up there and made a big mess for future generations to clean up. But on the other hand, the whole project is just such an amazing feat of science and engineering. We are still learning things from samples collected there. It gives me hope, even in this time when funding for climate research is being slashed, to think that we as a species are really good at doing impossible seeming things, that we can figure out how to carve a city into the ice or drill a hole a mile down into it. And so hopefully we can also figure out how to clean up after ourselves. If you want to read more about Paul Biermann's work, or the history of ice coring or the weird wonders of Camp Century, check out his book when the Ice is Gone. This episode was produced by me, Bird Pinkerton. It was edited by Jorge Just with help from Julia Longoria. Meredith Hadnot runs our show. Noam Hassenfeld makes our music. Christian Ayala did the mixing and the sound design. Melissa Hirsch checked the facts and I am always, always grateful to Brian Resnick for co creating the show. I'm also very grateful to Andrea Dutton for her time. She really, really helped me understand a lot about sea level rise and the oral history recording of the Herb Uita came from the Byrd Polar and Climate Research Center Archival Program which is part of the Ohio State University Libraries. We will link to it in the transcript. If you have thoughts about Camp Century or thoughts about ice, or thoughts about pretty much anything, write in or send us a recording. We are@ unexplainableox.com and I truly love hearing from you all. If you want to support the show and help us keep making it, you can join our membership program. It [e-mail] members you'll get ad free podcasts, you'll get unlimited access to Vox Journalism. But also you will be supporting the work that we do here. And if you sign up because you love Unexplainable, if you wanted to tell our bosses that it would be very helpful. You can also support us by leaving us a nice rating. That's really appreciated. A review is also appreciated and if you just tell people in your life to listen, that is extremely, extremely appreciated. Unexplainable is part of the Vox Media Podcast network and we will be back in your feed next week.

[Paul Bierman]

Ice ice slipping on the ice on the quasi liquid layer on the outside.

[Richard Alley]

Ice ice Slipping on the ice on.

[Paul Bierman]

The quasi la liquid layer on the.

[Richard Alley]

Outside ice ice Slipping on the ice.

[Paul Bierman]

On the quasi liquid layer on the.

[Richard Alley]

Outside ice ice Slipping on the ice.

[Paul Bierman]

On the quasi liquid layer on the outside y ice is slippery.