Ice Sheet Time Machine

10:23Paul Bierman:Until about five years ago, there were three publications on the frozen soil.

10:28Richard Alley: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.

10:39Paul Bierman:And yet... I think the focus of the community was almost laser on the ice and not on the stuff beneath it.

10:46Richard Alley:In fact, there was so little intention being paid to the soil from underneath Camp Century that it somehow kind of disappeared.

10:57Paul Bierman:There's a mystery around this that many people have taken to their graves, and we will probably never know exactly what happened.

11:03Richard Alley: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.

11:13Paul 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.

11:22Richard Alley:Paul spoke to some people who thought they'd ended up in Denmark, maybe, but nobody really seemed to know.

11:29Paul 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.

11:44Richard Alley: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.

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14:01Paul Bierman:I don't know anything about a core. That's it! You want some of this? Where's the core? Where's the core?

14:07Richard Alley:I wish I loved anything, as much as Richard Alley loves ice.

14:11Paul Bierman: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 Mulan, 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.

14:37Richard Alley: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.

14:49Paul Bierman:I started summer after freshman year.

14:52Richard Alley:Oh, so you know a thing or two about ice.

14:56Paul Bierman:Coming up on 50 years.

15:00Richard Alley:And it was actually a great time to get into ice research. The Camp Century Corps had come out of the ice sheet. And that corps, along with ice from another site called Dye 3, wound up raising all kinds of interesting questions about these abrupt changes in past climate.

15:16Paul Bierman: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 Dye 3 have told us what we have to know. Let's go find out.

15:33Richard Alley: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.

15:46Paul Bierman: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.

15:57Richard Alley:But the Sterling 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.

16:13Paul Bierman: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.

16:32Richard Alley:Oh, just one more thing to worry about.

16:34Paul Bierman:It's small. It's not, you know, there's lots and lots of bigger things to worry about in that world. But nonetheless, this happens.

16:44Richard Alley: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?

17:07Paul Bierman:And when this was first measured in the 90s, it was right at the edge of what was doable.

17:14Richard Alley: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.

18:05Richard Alley: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 that it was lots warmer than today.

18:33Paul Bierman: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.

18:44Richard Alley:Which 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.

19:25Richard Alley: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 20 feet of sea level rise just from Greenland's ice. We talk about the huge problems that could come from 3 feet of sea level rise. 20 feet could mean coastal cities underwater and millions and millions of people potentially displaced.

19:56Paul Bierman:And it's 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 say, 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.

20:27Richard Alley: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.

21:04Paul 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.

21:33Richard Alley: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.

22:12Paul 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, there's a picture of me with a little hat over my bald head and tiny little gloves for like skiing in the spring and one jacket. They walked in.

22:32Richard Alley:The scientist they were with told them a little bit about the new facility.

22:35Paul Bierman:And then he waves at like three of us. 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 Corps. 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?

23:09Paul Bierman:Is this here?

23:12Richard Alley: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.

23:27Paul 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'd cut it down the middle and they'd sent us half. And it was, oh, less than a pound of material.

23:51Richard Alley:They popped the samples in the freezer and then the next day, they took them out to photograph them.

23:57Paul 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 at this point, they were lumps of mud, right? The frozen, they just turned into mud.

24:27Paul Bierman: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 are 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.

25:01Paul Bierman:And I looked at this bin and I looked over at Drew Crist, 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.

25:36Paul Bierman: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've ever been swimming in a mucky pond, and, you know, 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.

26:10Paul Bierman:And it turns out now there's soil fungus in there. There's bugs. There are little midges. There's dozens of different forms of life.

26:22Richard Alley: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.

27:00Richard Alley: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 billions or even the hundreds of billions. And if we have the sea level rise wrong, if it doesn't rise as much as they build for,

27:34Paul Bierman: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 Katrina's. We have cities flooding and lives lost and properties, and now 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.

28:18Paul Bierman:And there's a lot to do.

28:23Richard Alley:When the U.S. 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, Camp 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.

29:15Richard Alley: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.

30:07Richard Alley:If you want to read more about Paul Bierman'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 Hadnott runs our show. Noam Hasenfeld 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.

30:47Richard Alley:And the oral history recording of Herb Uita came from the Bird 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 at unexplainable at vox.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 is at Vox.com slash members. You'll get ad-free podcasts. You'll get unlimited access to Vox journalism.

31:28Richard Alley: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.

32:14Paul Bierman:Slippin' on the ice on the quasi-liquid layer on the outside. Ice, ice, slippin' on the ice on the quasi-liquid layer on the outside. It's Y-I-E ice is slippery. Class is now in session. And the UPS Store is here to help you ace arriving on campus.

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