E25 – Antarctica’s Oldest Ice

Robert Mulvaney (front, dressed in black) and the Beyond EPICA surveying team. Credit: British Antarctic Survey

Drilling engineer and ice core scientist Robert Mulvaney has driven thousands of kilometers over Antarctica in the past few years in a snow tractor, creeping slowly over one of the highest points of the ice sheet, near a location known as Dome C. He’s looking for the perfect place to drill one and a half million years into the past. Gas trapped in the ice as it formed holds clues to Earth’s past climate and, Mulvaney believes, the atmospheric conditions that influenced the onset and denouement of the major glaciations of our current ice age.

To drill that far into the past, Mulvaney, the science leader of the Ice Dynamics and Palaeoclimate team at the British Antarctic Survey, and his colleagues with the EU-funded Beyond EPICA—Oldest Ice Core project need to find the perfect ice patch that is both thick enough to span 1.5 million years, yet has not melted at the bottom into a lake under the ice. In this episode of Third Pod from the Sun, he talks about camping at the bottom of the world, the beauty of the ice and how Antarctica is still the continent of exploration.

This episode was produced by Liza Lester and mixed by Kayla Surrey.


Shane Hanlon:              00:01                Hello, Nanci.

Nanci Bompey:             00:02                Hi, Shane.

Shane Hanlon:              00:05                I racked my brain for some cute introduction. I don’t have anything today. But, we do have something to talk about. Today we’re talking, in some part, about ice cores, right?

Nanci Bompey:             00:14                Yep, which are a very thing that people do in science …

Shane Hanlon:              00:19                Is retrieve them.

Nanci Bompey:             00:20                Yes.

Shane Hanlon:              00:20                They don’t create ice cores.

Nanci Bompey:             00:21                No, no. It’s a big thing though in climate science. I don’t know if many people know that. But in a lot of the stuff that we know about past climate is through drilling down into the ice sheet and bringing up these ice cores and seeing all the stuff that happened.

Shane Hanlon:              00:33                Yeah. And you’ve been up close and personal. Maybe not necessarily with the drilling process, but you’ve seen. Have you held ice cores?

Nanci Bompey:             00:38                No, I never held one but I went to the National Ice Core Lab which is-

Shane Hanlon:              00:40                Where’s that-

Nanci Bompey:             00:41                … outside Denver. Actually, yeah, I was out in the Denver/Boulder area for various things and I was touring a lot of different labs out there because there’s so much science.

Shane Hanlon:              00:50                Was this a work thing?

Nanci Bompey:             00:51                No, it was. I was invited to go to NCAR.

Shane Hanlon:              00:53                Okay.

Nanci Bompey:             00:53                Anyway, I was out there, and my sister also happens to live out there. So I was staying there for a while. So I said, “Why not hit up all these places?” So I got to go to all these cool places and one of them was the actual Ice Core Lab. So I said, “Oh, I’m going to be in town. Could I come by?” And they were just like, “Sure. We have a tour group that you can join.” Because they’re not going to just do a tour for one person.

Shane Hanlon:              01:10                But they do tours?

Nanci Bompey:             01:11                Yes.

Shane Hanlon:              01:11                Okay.

Nanci Bompey:             01:12                So I was like, “Sure.” So I go down there and it was a tour of retirees from somewhere in Colorado, a church group and me on the tour. But the guy who did it was amazing, because these are not necessarily science people. He was really good at explaining it including the question, “Well, is there really climate change?” And the answer was definitively, yes. And we know from these ice cores. You get to actually go into the freezer where the keep the ice cores and see them. My phone died, it was so cold, but very cool. I took some pics.

Shane Hanlon:              01:45                I can just imagine you with this group of retirees. You probably felt right at home. Did you tell them you have a mini van?

Nanci Bompey:             01:51                No.

Shane Hanlon:              01:57                Welcome to the American Geophysical Union’s podcast about the scientists and the methods behind the science. These are stories you won’t read in the manuscript or hear in a lecture. I’m Shane Hanlon.

Nanci Bompey:             02:06                And I’m Nanci Bompey.

Shane Hanlon:              02:08                And this is Third Pod from the Sun.

Shane Hanlon:              02:15                Okay. So we’re not talking about mini vans, your mini van, your own personal mini van.

Nanci Bompey:             02:19                I could transport ice cores in there, maybe.

Shane Hanlon:              02:21                Right. So, ice cores, what’s today about?

Nanci Bompey:             02:24                Today is about ice cores. I talk to Robert Mulvaney and he is a chemist who’s also a engineer. And he is getting ready to drill a core out of 10,000 feet of ice to learn about the history of our planet’s atmosphere. They have this project, it’s called Beyond EPICA: Old as Ice. And their goal is to drill back, to go back 1.5 million years ago. So like I said, with the ice cores you can actually go back and look at what a past climate was like. So, what happens is that there’s stuff in the atmosphere like a volcanic eruption or how the chemicals in the air are. But it’s trapped in the ice basically. And then snow falls on top of it and makes these ice cores. So the scientists drill down into the ice and then looking back in time, they can see where all these happened and they can actually date things in the ice.

Shane Hanlon:              03:19                Like different layers, essentially.

Nanci Bompey:             03:20                Yeah.

Shane Hanlon:              03:20                Okay.

Nanci Bompey:             03:20                And we’ve talked about this before. Coring is a thing in Geo science. There’s mud cores, there’s sediment cores, the way to go back and look at all these past climates. So when you want to learn and go back this far, they’re hoping that this might be the farthest back that they can go.

Shane Hanlon:              03:39                Very cool.

Nanci Bompey:             03:39                Not that they can go, but that scientists have gone with this ice core.

Shane Hanlon:              03:45                All right.

Nanci Bompey:             03:46                Yeah.

Robert Mulvaney:         03:53                Okay. Dr. Robert Mulvaney from the British Antarctic Survey where I’m a glaciologist, or more specifically, an ice core scientist.

Nanci Bompey:             04:00                Okay, an ice core scientist. So, what does an ice core scientist do?

Robert Mulvaney:         04:04                Ice core scientists drill ice cores in the polar regions, or in my case, in the polar regions. And then they try to reconstruct the climate and the atmosphere of the past.

Robert Mulvaney:         04:15                I’ve drilled cores in and all over the place. But to me, the best places are Antarctica. And the reason I like Antarctica is that’s where the oldest ice on earth exists. So we can get the climate record from the ice. We can get it from marine sediment records, for example. But the only place on earth that you can access old air is locked in these deep ice cores, or locked in the deep ice in the polar regions, particularly Antarctica, because that’s where the oldest ice is. So that’s what we’re trying to do. We can actually get back to this ice that, hopefully, is 1-1/2 million years old.

Robert Mulvaney:         04:49                I went to university to study as a chemist. My intention was I wanted to become a forensic chemist. And within a year or two of arriving at university, I saw on the lamp post, a little poster that said, “Come along to this talk by the British Antarctic Survey.” And I went along to this talk and I was staggered. People are still working in Antarctica. They’re still, if you like, exploring the relics of continental science now, and I was staggered. And I thought, “Do you know what? That’s what I really want to do. Forensic science, I can still be a chemist.”

Robert Mulvaney:         05:20                So, underneath everything, I am still professionally, a chemist. And that’s where all the analytical chemistry comes from. But I just change from forensic chemist, looking at crime scenes and dead bodies, or I could go to Antarctica and try to look at the climate. So I went to Antarctica.

Nanci Bompey:             05:36                It’s like the forensics of the earth.

Robert Mulvaney:         05:38                It is the forensics of the earth, exactly. So I just change from bodies to the earth. I will have just been in the field this year on a British Antarctic Survey and Cambridge University project. So it’s just a joint two institutes involved. And we drilled all the way down to the bedrock, 561 meters down, hit the bed of the ice sheet, brought all that ice back. And that will give us a record of climate of about a past 150,000 years.

Robert Mulvaney:         06:05                Now what excites me about that one is if we go back 120,000 years, we’re back into the last interglacial. So the last time the climate was as warm as today, maybe a little bit warmer than today, six meters of extra sea level. So sea level was about six meters, between six and nine meters higher than today. So what we were looking at there with that project is what was it about the West Antarctic Ice Sheet that may or may not have contributed the extra six meters of sea level. So that’s one of the projects I’m involved with. It’s still 150,000 years, it’s still a long climate record.

Robert Mulvaney:         06:41                The other one I’m involved with at the moment, and the one that we’ve been particularly excited about today is the oldest ice. It’s called, Beyond EPICA: Oldest Ice Core. It’s all there in the name. The original EPICA: Ice Core was a big European project that finished back in 2004. I was there in the field on one of the drilling seasons and I did some of the analysis of that core. That gave us 800,000-year climate record, so, 800,000 years of climate and 800,000 years of atmospheric composition. So we were able to relate what was in the atmosphere, particularly the greenhouse gases to what the global climate looked like.

Robert Mulvaney:         07:17                And what we saw was, firstly there’s a very strong correspondence between atmospheric greenhouse gases and climate. That’s part of our natural global climate system. But we also saw that we have an ice age about every 100,000 years. But if we go back into marine sediment records and go back further in the past, then we can see that we have an ice age about every 41,000 years. Somewhere around about a million years ago, we swapped from that 41,000-year phasing to 100,000-year phasing. And this project, Oldest Ice, Beyond EPICA, it’s the next project after EPICA. It’s kind of the same grouping. Oldest Ice is to go back beyond 800,000 years to hopefully 1.5 million years, to see if we can see what the atmosphere was doing at this time when the longterm climate had a 41,000-year cycle between ice ages and warm periods.

Nanci Bompey:             08:08                And so why is it important to know that there was this change from the 100,000 years to the 41,000 years? Why is it important to go back that far and see all that?

Robert Mulvaney:         08:20                Okay. We know we’re in a 100,000-year world at the moment. And that is really being driven by the eccentricity of the earth’s orbit around the sun. If you go back beyond the million years, then it’s 41,000 years and that’s being driven by the earth’s obliquity, the tilt angle towards the sun. So these orbits around the sun change the amount of energy the earth receives, and that drives our longterm climate. Given that we don’t think the earth’s orbit has changed from billions of years, what we don’t know is why we switched from 41,000-year phasing to 100,000-year phasing. And I think for me, the answer lies in the atmosphere.

Nanci Bompey:             09:02                So I actually know about these cycles.

Shane Hanlon:              09:04                Yeah.

Nanci Bompey:             09:05                They’re called Milankovitch cycles.

Shane Hanlon:              09:07                John Malkovich cycles.

Nanci Bompey:             09:08                Yes. No, Milankovitch. Right, Liza? Milankovitch.

Liza Lester:                   09:11                Milankovitch.

Shane Hanlon:              09:13                Hi, Liza.

Liza Lester:                   09:14                Hey, guys.

Shane Hanlon:              09:15                All right. So, can you explain, not necessarily the Milankovitch, but more about these cycles?

Liza Lester:                   09:22                Yeah. Remember when we talked about the ice ages, the glaciation phases, a few episodes ago?

Shane Hanlon:              09:29                Yeah.

Liza Lester:                   09:30                Yeah. It’s kind of like that. You have these periods when the ice sheets grow and then they shrink, and it’s balmy like it is now or in between glacial periods and it’s nice. Up until about a million years ago, those were happening on this 41,000-year cycle like he mentioned. And then for some reason, it became a 100,000-year cycle. And they’re like, “Well, the orbit of the earth didn’t change. And the tilt of the earth didn’t-

Nanci Bompey:             09:52                Because those are-

Liza Lester:                   09:52                … hardly change”-

Nanci Bompey:             09:52                … things that affect these cycles.

Liza Lester:                   09:53                Yeah. So like, “What happened?” And so part of why they want this ice core going back 1.5 million years is so they can span that whole time. And then maybe he can see something in the atmosphere that might give us clues to why this happened.

Shane Hanlon:              10:07                This difference of 60,000 years is pretty significant.

Liza Lester:                   10:10                Yeah, it might matter. It might matter.

Nanci Bompey:             10:12                Yeah, so they had to find the perfect spot-

Liza Lester:                   10:15                The-

Nanci Bompey:             10:15                … to go-

Liza Lester:                   10:15                … perfect spot-

Nanci Bompey:             10:15                … go drill this-

Liza Lester:                   10:16                Yeah-

Nanci Bompey:             10:16                … ice cores.

Shane Hanlon:              10:17                For the perfect core.

Liza Lester:                   10:18                That’s real deep. That’s a long time.

Shane Hanlon:              10:18                That’s real deep. No, literally. I could feel that, too. It’s the perfect thing, real. All right, I’m done.

Nanci Bompey:             10:30                So how do you find where you’re going to drill? How do you find where you’re going to drill? How do you know that that 1.5 million-year ice is there?

Robert Mulvaney:         10:37                Well, most people say, “Well, you drill 3,270 meters at EPICA. Why don’t you just find somewhere a bit deeper?” If it was as simple as that, we’d be able to find a deeper spot in Antarctica and go and drill there. But it’s not as simple as that because the bottom of the ice is melting over much of Antarctica. Much of Antarctica is underlain by lakes. And those lakes come from the basal ice melting. And it’s melting because of geothermal heat flux.

Robert Mulvaney:         11:04                So the earth being emitted by the earth’s mantle, it’s trapped by the overlying layer of ice. And the thicker it is … It’s like a big, thick blanket, it just insulates the bottom of the ice. And the bottom ice melts away. So at EPICA, we only got 800,000 years because it was actually melting at the bottom. So there was no older ice. The deepest ice core ever drilled in Antarctica at a place called Vostok is even deeper still than EPICA, 400 meters deeper, but only 440,000 years. But it’s underlain by a huge lake, Lake Vostok, that is the old ice, if you like. That’s where all the old ice is going, it’s now-

Nanci Bompey:             11:40                It’s in-

Robert Mulvaney:         11:40                … in the lake-

Nanci Bompey:             11:40                … in the lake.

Robert Mulvaney:         11:40                Yeah. So it’s useless to us. The gases have gone, it’s just useless to us. So what we’ve got to do is find somewhere where it’s not too deep, not too shallow. We don’t need it too shallow because we need as much ice as we can to give us the resolution of that climate record. We don’t need it too deep because then we’ll lose the bottom ice through melting. So we’ve got to find just the right spot.

Robert Mulvaney:         12:02                And people have modeled where just the right spot might be, and there’s only a few places. There’s one near Dome C, which is the original EPICA core. There’s one near Dome F, where the Japanese drilled a core that went back 750,000 years. There’s one near Dome A, which is the highest spot in Antarctica. So there’s a few places that you might go to. So there’s a few places that you might go to. And we’ve been looking for the last three years, again, funded by the European Union, for this spot that’s somewhere close to the EPICA core. Now I have been in the field for two of the last three years. And my job was to drive around towing radar around for a very detailed look at the bedrock. I drove 2,500 kilometers at about 10 kilometers an hour, it’s slow. There’s a lot of effort. We knew more or less where the area was. We had an area we called Little Dome C. It’s about 40 kilometers from Dome C itself, from where the EPICA core was drilled.

Robert Mulvaney:         12:58                And we did about 2-1/2 thousand kilometers over two seasons, dragging the radar along the surface. And then we could reconstruct what the topography underneath the ice looked like, how thick it was, what was there.

Nanci Bompey:             13:10                From the radar?

Robert Mulvaney:         13:11                From the radar. But the thing we could also see in the radar is that once you’ve built up the topography of the bottom, it’s like a plateau with deep incised channels in it. And at the bottom of those channels, those deep valleys, was water. So actually, in that area, there is quite a lot of water. But on the areas that are a little bit shallow, there appears to be no water at the bottom. So the other thing I was doing is drilling deep into the ice. I was drilling between 400-500 meters, just drilling a bore hole, not bringing an ice core out, but just drilling a bore hole. I brought the ice chippings out so I was able to analyze those. But the thing I was really trying to get at is to be able to drill a hole deep enough to put in a very sensitive temperature-measuring system that would give me a temperature every meter down the ice sheet.

Robert Mulvaney:         13:54                And with that, and a few other bits of radar that allows us to understand how quickly the ice is flowing in a vertical direction, so how quickly it’s compacting, with those two things together we could predict the basal temperature and the geothermal heat flux. That then allows us to be fairly confident we haven’t got melting at the bottom. And that’s absolutely critical because what we don’t want to do is spend five years drilling a deep ice core and get to the bottom and find, “Oh, it’s wet. It’s melted.”

Nanci Bompey:             14:22                Exactly, exactly.

Robert Mulvaney:         14:26                I have never been. Have either of you been to Antarctica on the ice?

Nanci Bompey:             14:29                No.

Liza Lester:                   14:29                Sadly, no.

Shane Hanlon:              14:31                I don’t know. We’re scientists. People have done stranger things. Anyways, what does camp look like of them? Where do they stay? Or what are those conditions like?

Nanci Bompey:             14:41                Yeah. Because they’re at this place actually called Dome C.

Shane Hanlon:              14:44                Dome C. Okay.

Nanci Bompey:             14:46                Which is this rise.

Liza Lester:                   14:47                Yeah-

Nanci Bompey:             14:49                Rise up on this narrow plateau.

Liza Lester:                   14:49                They’re interior 1000 miles from the coast on this big plateau in Antarctica. It’s just the ice sheet. They’re 3,000 meters up, it’s pretty high. And so these domes are like a little rise, the highest points, on this big plateau. But if you’re standing there I think it doesn’t really look like you’re on a hill.

Nanci Bompey:             15:09                And this is one of the places where there’s research stations.

Liza Lester:                   15:11                Yeah. The French and Italians have a research station at this Dome C or Concordia Research Station. But I think the ice survey team was even farther afield. So they didn’t even get to stay at the station. They’re …

Nanci Bompey:             15:25                In a more remote-

Liza Lester:                   15:25                … farther out.

Nanci Bompey:             15:25                … more remote area out by where they had to be. They were looking for where to drill, basically.

Liza Lester:                   15:30                They’re looking for where to drill, yeah. Where’s the deepest place and where’s the best spot?

Robert Mulvaney:         15:35                Okay. We were off station, so there was, in the first season there was five of us, in the second season six of us. So quite small groups. We’re living in a converted container, so if you imagine a shipping container, that somebody’s put a few bunks here and a kitchen, and a table. That’s how we were living and it was actually quite comfortable. Ordinarily, when I work in a British project I live in a tent.

Nanci Bompey:             16:00                Oh, so you had a container this time.

Robert Mulvaney:         16:01                We had a container, yeah. So I’ve got all the markets along the way, nice French and Italian food. It was really very, very, very, very good. And what I would do is, every morning we would fire up the big vehicles. So we’re driving snow tractors. They’re the things that would be used in a ski resort to piste bash the piste. So I was driving around on one of these, towing the little tiny radar behind us. Now the radar looks tiny behind this big tractor. Because it’s designed to be towed behind Ski-Doos because that’s the way the British work. It was a British radar designed to be towed behind a Ski-Doo so it was kind of tiny, but this massive big tractor towing this little, tiny radar. But we just drove up and down in a grid pattern. And then each evening, I would work up all the data and then try and plot it in three dimensions.

Robert Mulvaney:         16:47                So as the time went on, we were building a picture of the base. And actually being able to in real time, every evening look at what the area was developing like, what the base looked like, and try to say, “Well, tomorrow, let’s go and look at this area over here because that looks interesting”, and refine it. So we were actually refining …

Nanci Bompey:             17:05                As you were going along.

Robert Mulvaney:         17:06                As we were going along. And once we found areas that were interesting we’d put more effort in those areas. So because we were able to work up the data in real time, it meant I could make decisions on the ground about what looks good.

Nanci Bompey:             17:18                So how many weeks did that take in total?

Robert Mulvaney:         17:21                I’d guess out of each of those periods, I was probably out at the field site for about 40 days, something like that.

Nanci Bompey:             17:26                Oh, wow.

Robert Mulvaney:         17:27                So, a reasonable length of time.

Nanci Bompey:             17:28                Yeah, yeah.

Robert Mulvaney:         17:28                It takes quite a lot of effort. These areas are so cold that they’re not long field seasons. So, really the field season starts at about the beginning of December and is finished by the end of January. Beyond those periods, it’s just getting too cold. To give you a feeling for it, the temperature, when I first arrived the morning temperature would be about -45.

Nanci Bompey:             17:49                C.

Robert Mulvaney:         17:49                Celsius, yes. -45 celsius. So we’re getting up at that sort of temperature walking about 400 meters to the station from our breakfast. The cold catches in your throat, catches in your nose. It does feel cold. Then by the middle of the season, the warmest days were about -25. So that’s a warm day.

Nanci Bompey:             18:12                Did you wear a T-shirt?

Robert Mulvaney:         18:13                No.

Nanci Bompey:             18:14                Not quite, yeah.

Robert Mulvaney:         18:15                I was well dressed.

Nanci Bompey:             18:16                Yeah.

Robert Mulvaney:         18:16                But to be honest, it’s not only the temperature that does you in. It’s the wind. Generally speaking, in these high altitude, inland sites there’s not so much wind. When I work near a coastal site in the area that Britain tends to work in, we tend to get very high winds. This last season that I’ve been working drilling this only 651-meter core we got winds of 40 or 50 knots, and actually that can be just excruciatingly bad.

Nanci Bompey:             18:51                So you’re out there, this particular thing you said you weren’t in the camp. You guys were out there alone.

Robert Mulvaney:         18:56                We’re not on the station. We’re remote from the station. The station’s quite a comfortable year-round station run by the Italians and the French. And it’s very comfortable and designed for when the lowest temperatures in winter might reach -80. It’s designed for those sorts of conditions so it’s a very comfortable station. But we were about 40 kilometers off the station living in this container and doing all our work. So we would have left the station and come back at the end of the season.

Nanci Bompey:             19:24                So what’s it like, I guess, to be out there. You’re doing your work during the day, you’re probably busy. But at the end of the day and you’re out there, I don’t know, to be out there in this place that few humans have been, with five or six of you, is it incredible? Is it scary?

Robert Mulvaney:         19:42                It is incredible. I think I’ve been to Antarctica now, 24 times.

Nanci Bompey:             19:46                Wow.

Robert Mulvaney:         19:46                And I’m very tired of it. To me, every season is different. Every season’s got it’s new challenges, it’s new excitement. It’s a new team each season normally, so I get to meet different people. And I just love working in those sorts of conditions. I really like the remoteness. It can be very, very beautiful, extremely beautiful, especially when the sun’s shining. It can be extremely beautiful when it’s blowing a blizzard. It’s just a different type of beauty. I really like the close-knit community that develops. I really like working in these small groups of just half a dozen people. It’s quite intense. You really get to know each other very well. You’re quite reliant on each other. You’re certainly reliant on each other if anything goes wrong because it’s a very small community. There’s no instant access to medical care, for example, if things go really desperately wrong.

Robert Mulvaney:         20:34                So you really are quite reliant on the people around you. Every evening we all sit around, we chatter. I think working with the Italians, we would sit around with a nice meal, a bottle of wine and we’d talk about the regional specialties of the food that’s on offer tonight. Again, if I contrast it to working at a British camp, it’s dried food every evening. It’s dried chicken marsala, dried chicken curry-

Nanci Bompey:             21:02                Something else.

Robert Mulvaney:         21:03                Dried chicken chili. It’s more or less the same meal every night of the week, and dried. But the Italians really like to lay on decent food. They love their food in the field. And I enjoy that, too.

Nanci Bompey:             21:15                That sounds nice. That sounds nice. So what’s next? Now you’ve done the radar, you’ve mapped it out. You’re like, “This is where we’re drilling.”

Robert Mulvaney:         21:22                Okay. We’ve found the spot. So what will happen now is that they’ll start to build a camp in the area. And we’re a summer-only camp and they will build a camp that’s designed to look after 14 people. We’ll be drilling over 16 hours a day at the beginning and the end of the season when it’s cold, and then 24 hours a day in the middle of the season when its warm, as in, it might reach -25. But they are cold conditions to stand around operating a drill. So we don’t tend to drill 24 hours a day at the beginning and end of season. It’s just way too cold.

Nanci Bompey:             21:56                And how long does it take to do that drilling and pull up-

Robert Mulvaney:         21:59                So-

Nanci Bompey:             21:59                … a core-

Robert Mulvaney:         22:00                … we’re going to take one season to settle, and about three, perhaps four, seasons to drill all the way through to the base which is about 2,800 meters at the point that we’ve chosen. So it will take about three seasons of drilling.

Nanci Bompey:             22:13                Just to get down there.

Robert Mulvaney:         22:14                Just to get down there. Now on a good day you might drill 20 to 25 meters on a good day. And a good day being 16 hours or so. That’s about the rate that you’d drill at.

Nanci Bompey:             22:22                And are you just standing there watching it, making sure nothing is going wrong? What are you doing as this thing drills?

Robert Mulvaney:         22:27                The drill itself is suspended from a cable. The cable carries the power down, it also carries information back from the drill so we know what it’s doing. And really, on the surface, the only control you’ve got is to turn the drill on and off, maybe add a little extra power to the drill, maybe change the rate it’s rotating out to the head, and just monitor what’s going on. So once the drill goes down into the hole, it might take 20 to 30 minutes to transit the hole, to get into the base. Then you’re setting it. Drilling, it might take 15 to 20 minutes to drill two to three meters of ice. And then you bring it back to the surface with another 25 minutes transit time.

Nanci Bompey:             23:02                Oh, because you’re bringing back these chunks.

Robert Mulvaney:         23:03                Exactly.

Nanci Bompey:             23:03                These two-to-three-meter chunks.

Robert Mulvaney:         23:04                Yeah. So, because we’re building quite deep, we’re building the drill to bring about between three and four meters out to each site each time it goes down the hole. We’re not sure yet because the drill is not built, but we are in that phase at the moment. But about three meters, so each time it goes down the bore hole. So that comes back to the surface. The core is taken out of the drill. The drill is cleaned up, all the chippings removed. And then it goes back down the hole again.

Robert Mulvaney:         23:27                So if you imagine when the drill comes to the surface, what happens then is it’s obviously vertical because it’s just come up from the bore hole. We actually tilt it to the horizontal to make it easy to work on. And the inner barrel which contains the core slides out. Behind that is all the chippings from the drilling itself. These are all cleaned out and the drill is cleaned up, and the bough is brought back in again. And it goes back down the hole.

Nanci Bompey:             23:47                And you pack up the ice core. Are you doing any analyzing right there?

Robert Mulvaney:         23:51                All right. Okay, because we’re off station and we’re limited to only 14 people in the field, most of those will be drillers. They’ll be two or three people whose job it is to just, what we call, log the core. So basically, just say, “All right, you’ve got a piece of ice here. It’s got breaks in these places.” Any physical damage to it will be recorded and then they’ll put it into one-meter sections and then box them.

Robert Mulvaney:         24:14                Then those are then transferred back to Concordia Station where we do a little bit of work on them. We’ll measure some electrical measurements on it, some non-destructive electrical measurements on the ice. But then the ice will be cut horizontally, so longitudinally into half. Half of it will then be stored in the field as an archive. Because it’s cold in the field it’s a natural refrigerator. And the other half will be packed into insulated boxes and brought back all the way to Europe.

Robert Mulvaney:         24:43                Now we’re going to try and bring most of it back at -20. But some of it we’re going to try and bring back at -50. Because some of the things that we want to measure are deep in the ice. It actually might start to change very slightly if the temperature warms above -50. So we’re going to try and bring it all the way back to Europe at -50. That’s actually quite a challenge.

Shane Hanlon:              25:00                He says it’s a challenge. Sure, over Antarctica or whatever, it’s really cold down there. But we have … I don’t know, -50 C is really cold, I get that, deep freezers and stuff. Can’t you just buy equipment to keep things cold?

Nanci Bompey:             25:17                Well sure. But it’s not like a normal thing. Like-

Liza Lester:                   25:19                Yeah-

Nanci Bompey:             25:20                [crosstalk 00:25:20]-

Shane Hanlon:              25:20                You don’t have a-

Nanci Bompey:             25:20                50 degree C-

Shane Hanlon:              25:20                You don’t have a -50 C freezer?

Nanci Bompey:             25:22                Plus they have to transport it all the way from Antarctica. They’re a thousand miles from the coast, something like that, all the way to the ship that goes to the tropics, to get it all the way back up to where they are in Europe. So that’s with preserving it.

Liza Lester:                   25:38                Yeah. They just pack it in one of those container things like you see on a container ship. And hope it makes it in this refrigerated thing. But yeah, it sounds like the -50 celsius is an expensive piece of equipment.

Nanci Bompey:             25:49                And could you imagine opening that when you get to Europe and you’re like, “Oh, it’s a pile of water.”

Liza Lester:                   25:54                That would be bad.

Nanci Bompey:             25:55                That would be the saddest thing that ever happened.

Shane Hanlon:              25:57                Ever.

Nanci Bompey:             25:58                Ever.

Shane Hanlon:              25:58                Especially for someone who does this.

Nanci Bompey:             26:01                Yes.

Robert Mulvaney:         26:02                What you don’t want to do is you have a freezer breakdown in the tropics.

Nanci Bompey:             26:04                And you get a puddle of water.

Robert Mulvaney:         26:04                And you get a puddle of water. I’ve done this with my own projects in the past. I’ve got it back to the station. There’s been a breakdown of the Reefer and I’ve got a puddle of water.

Nanci Bompey:             26:15                What does that feel like when you open that up?

Robert Mulvaney:         26:17                It feels terrible and there really is nothing you can do about it at that stage. And of course if you think about it, the ice has come from close to the bottom. It might have taken you two or three years to get there. So you just don’t want to start all over again. So that supply line all the way back to Europe is quite critical to us. But it’s also the reason why we leave half of it in the field. Because at least then, if there is a disaster, we’ve got, longitudinally the other half of the ice still in the field.

Nanci Bompey:             26:44                Right, right, right. So then once you get it back home, what do you do in the lab with it? How do you analyze that?

Robert Mulvaney:         26:52                It will be distributed amongst all the institutes that are involved. Some of it will be taken for gases. In a way they’re the most important thing we’re trying to measure. They’re probably the whole key to the project, is what was in the atmosphere 1-1/2 million years ago. You’re trying to break it down without actually melting it. And then you take that air out and you put it into instruments to measure things like carbon dioxide, methane, nitrous oxide, the main greenhouse gases.

Robert Mulvaney:         27:19                The way we get the climate record is we look at the isotopic composition of the water molecules. So water is H2O. They are heavy and light isotopes of oxygen, heavy and light isotopes of hydrogen. And these vary, the ratio of heavy to light isotope of each of the atoms varies with temperature. Because the heavier isotope has a higher vapor pressure. Therefore it takes more energy to lift out the ocean and maintain in the atmosphere. So when you’ve got a lower temperature you get less of the light isotope. So the colder the temperature, the more depleted the ice is.

Robert Mulvaney:         27:59                So what we’re doing is we’re taking that measurement and that will give us the temperature. So we measure a whole range of chemical parameters on the ice. So what we’re trying to do is look at the atmosphere to know what was going on in the atmosphere. We looking at the chemistry of the ice to understand a lot about environment. And we’re looking at the water isotopes themselves to tell us about the climate.

Robert Mulvaney:         28:21                So we take those three together and we build up a picture of what the atmosphere, the local environment, or the long distance and what’s coming from the oceans, what’s coming from the continents in terms of dust, and put that all together to understand how the climate atmosphere and ever under the circulation of the meteorologic patterns around Antarctica, how are they all coming together to give us this pattern that we see in the ice?

Nanci Bompey:             28:44                Hopefully. Yeah, so what was the earth like 1.5 million years ago?

Robert Mulvaney:         28:49                I suspect it was not that different to today. If you were in a warm period 1.5 million years ago, it’d probably look very similar today. If it was in a cold period it would look like a glacial period.

Nanci Bompey:             29:00                And so this is going to help us figure out what is going on now with our climate?

Robert Mulvaney:         29:05                That’s part of it. There’s a fundamental desire, if you like, partly to go back and discover something new. What was the atmosphere like 1-1/2 million years ago? But I think there’s also a philosophical question we’re asking of ourselves. And that is, if we don’t understand why we’ve moved from a 41,000-year cycle to a 100,000-year cycle, and we don’t, we’ve got some hypotheses, we need to test them, but fundamentally we don’t understand that, being locked into the tilt angle of the earth’s orbit to being locked into the eccentricity of the earth’s orbit. We don’t know why we’ve changed that. And if we don’t really understand that can we really, honestly say we understand so much about the climate that we can predict the next 200 years?

Robert Mulvaney:         29:47                So part of it is philosophical. It’s understanding the climate system as a whole. And part of it of course, is what we understand about the next 100 years and how the climate will react to increasing greenhouse gases, they are based on models. They’re based on mathematical models, they’re forecasting the future. Now those models have to be ceded by some knowledge of how the atmosphere and the climate have reacted in the past. And that comes from our deep ice core record. So by understanding the climate of the past and the atmosphere of the past we can help refine the models that predict the future. So there is a link to what’s happening to our future climate.

Nanci Bompey:             30:24                Uh-huh (affirmative), uh-huh (affirmative).

Nanci Bompey:             30:30                So are you super excited to go back out?

Robert Mulvaney:         30:33                I’m quite proud of the fact that I was involved in finding this site. I think if we drove to the bottom and we find oldest ice at the bottom, then I’m going to put my hand up and say, “I chose that site.” If we get to the bottom, we find that the ice isn’t old, I’m going to put my hand up and say, “The committee chose this site.”

Nanci Bompey:             30:51                That’s great.

Robert Mulvaney:         30:54                But I’m also looking forward to going back out and taking part in the drilling. Because as well as doing radar, I do drilling as well. So I am a driller/engineer as well as a scientist. So I try to cover all the bases and I’m quite looking forward to getting back out there and drilling the core itself.

Nanci Bompey:             31:10                Yo, these scientists are hard core.

Shane Hanlon:              31:12                Yo, these scientists are good. They are hard core. We were talking about this before and Liza brought up a good point that they should have sent these guys to the asteroid in Armageddon.

Liza Lester:                   31:24                Right. You don’t need Bruce Willis and his knucklehead friends.

Nanci Bompey:             31:27                You need a scientist.

Liza Lester:                   31:29                These scientists are like …

Shane Hanlon:              31:29                Yeah.

Nanci Bompey:             31:31                You need Robert Mulvaney.

Liza Lester:                   31:31                They know what they’re doing. Let’s send them to space to dig a hole in the asteroid and save all of humanity.

Shane Hanlon:              31:36                Yeah, yeah. To them go the glory. That was the initial downfall of science depiction in film.

Liza Lester:                   31:43                They were neviche …

Nanci Bompey:             31:43                A nerd.

Liza Lester:                   31:46                Nerds.

Nanci Bompey:             31:46                Yeah.

Liza Lester:                   31:46                Just sitting there with our data. And not-

Nanci Bompey:             31:48                They are not-

Liza Lester:                   31:48                And not that we don’t-

Nanci Bompey:             31:48                … at all-

Liza Lester:                   31:48                … do those things.

Nanci Bompey:             31:49                Yeah.

Shane Hanlon:              31:49                Sure.

Nanci Bompey:             31:50                But they are hard core.

Shane Hanlon:              31:51                Hard core.

Nanci Bompey:             31:52                They also camp on the ice for three years.

Shane Hanlon:              31:54                Yeah. I love cold, but no thank you.

Shane Hanlon:              31:57                All right. Well, that’s all for Third Pod from the Sun. I guess, thanks to Nanci for bringing us this story.

Nanci Bompey:             32:03                And extra special thanks to Liza for helping me with this story.

Shane Hanlon:              32:07                Thanks, Liza.

Nanci Bompey:             32:08                And of course, thanks to Robert for sharing his work with us.

Shane Hanlon:              32:11                This podcast was produced by Liza. And thanks to our sound engineer, Kerry [Lawserry 00:32:16].

Nanci Bompey:             32:17                And we would love to hear your thoughts on the podcast, of course. Please write a review, give us some high-star ratings on Apple Podcasts.

Shane Hanlon:              32:25                Yes, please.

Nanci Bompey:             32:26                You can find us wherever you get your podcasts, and then thirdpodfromthesun.com.

Shane Hanlon:              32:29                All right. Thanks, all. And we’ll see you next time.


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