Antarctic Glaciers Sliding Toward the Sea The massive Pine Island glacier is moving toward the ocean at about 3.5 kilometers per year; a trend mirrored by other remote glaciers also picking up speed. Glacier ice moving into the oceans around Antarctica has important implications for sea level rise worldwide.
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Antarctic Glaciers Sliding Toward the Sea

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Antarctic Glaciers Sliding Toward the Sea

Antarctic Glaciers Sliding Toward the Sea

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Now we've all seen pictures of the ice in the Arctic - the North Pole area, they've been all over the news lately. But because it is so remote and hard to get to, we don't usually hear much about ice in Antarctica. Well, we're going take care of that now, because my next guest has recently returned from Antarctica where he spent three months camped out in the western part of the continent with a team from the British Antarctic Survey.

They used GPS and other technology to try and get a handle on what is happening to the glaciers in that part of the world. And, of course, that part is near the south, near the South Pole - a few hundred miles away, but it is that southern part of the world that we're talking about, in Antarctica.

And they report that the massive Pine Island Glacier is slipping towards the sea in an unprecedented rate and they aren't sure why. There are some hunches, maybe an ancient volcano, maybe deep ocean currents.

Joining me now to give us his eyewitness views is Julian Scott. He is a geophysicist at the British Antarctic Survey in Cambridge, England. He's just back from a four-month trip to Antarctica.

Welcome to SCIENCE FRIDAY, Dr. Scott.

Dr. JULIAN SCOTT (Geophysicist, British Antarctic Survey): Thank you very much, Ira. Pleased to be here.

FLATOW: I'm sure having the name Scott in Antarctica, you've heard about it a few times.

Dr. SCOTT: I've certainly heard that a few times here. I'm no relation though.

FLATOW: To Robert Falcon Scott, very famous British explorer.

Dr. SCOTT: No.

FLATOW: You recently returned from Antarctica. Tell us what you were doing there.

Dr. SCOTT: Well, we were the - over the last two seasons of this year and a year ago, we were the first people to do an extensive on-the-ground survey of Pine Island Glacier, which is the glacier in Antarctica that's putting the most ice into the sea.

FLATOW: It's a big — is it big, relatively speaking?

Dr. SCOTT: It's huge. It's huge. It's about 30 kilometers across, about two kilometers thick, just absolutely huge, 200 kilometers long.

FLATOW: And it's very remote. Am I correct in saying that the last time anybody was there was 1961?

Dr. SCOTT: You're correct. Yes. As far as I'm aware, the last people to visit here before us was an American Sno-cat traverse(ph) team, and that was in 1961, and I think they just crossed the glacier and spent about a week there.

FLATOW: So there's a puzzlement, so to speak, about why the glacier is putting so much ice into the sea?

Dr. SCOTT: Well, yes. We're trying to work out what's going on because it's not just that it's putting a lot of ice into the sea. We've also noticed that it's been speeding up. Initially, from the satellite measurements in the 1990s, showed that the glacier increased its speed by about 10 percent. And the measurements that we've done just recently seemed to show that it increased by a further 30 percent since then. So we're — why it's increasing is a question that we want to answer.

FLATOW: And what might be some of the reasons?

Dr. SCOTT: Right. Well, one of the main and popular theories at the moment is this: Warm ocean — warm water in the deep ocean just off the continental shelf. And that is somehow being channeled up to the bit of the glacier where it meets the ocean and begins to float. And it's melting this grounding line of the glacier and therefore speeding it up from the ocean end, making that a bit more slippy, or maybe it's something that's happening inland. We're not quite sure at the moment.

FLATOW: Would the warmer water be due to global warming perhaps?

Dr. SCOTT: Well, no, the warmer water is there anyway. It's more - what's actually pushing it there towards the glacier - and is that different from, say, 50 years ago - are there different winds, different pressure systems in the southern ocean, which could be due to climate change, but we're not really sure at the moment. So that's very much — we're in the early stages of trying to work out whether that could be to do with climate change or just nothing to do with it whatsoever.

FLATOW: Why would it be a problem that needs to be studied if the glacier is moving so quickly?

Dr. SCOTT: Well, we certainly need to know - what we'd like to know - what's going to happen to the sea level globally over the next few centuries. All that flip defenses and our plans of where to build our houses and everything, again, depends on what's going to happen to these big ice sheets. And this particular area has shown so many signs of rapid change recently that it certainly could contribute significantly to sea level rise over the few centuries.

FLATOW: You mean, as the ice keeps slipping into the ocean?

Dr. SCOTT: Yes, certainly. And the amount that it's increased its speed is very significant recently to the point where just this glacier alone could perhaps contribute up to a centimeter over the next century. But what we want to know - is it going to increase its speed again? Are we seeing the start of something or are we just seeing something that happens every now and again and it's nothing really to worry about?

FLATOW: And so the fear there is that it could speed up and accelerate and…

Dr. SCOTT: Well, this is what we need to work out. So, one of the things that we're doing is we're looking — we're using geophysical techniques to look underneath the ice stream to see what the base of the glacier is made of, and hopefully doing some more work around on the ocean side of the glacier to see if we can estimate what - how it's going to respond in the future, whether this is the start of something big or whether it's just going to stabilize now.

FLATOW: Isn't there work on other glaciers? I'm particularly thinking about Greenland, which is sort of…

Dr. SCOTT: Yeah.

FLATOW: …the same terrain as Antarctica. And the idea that there's water that leaks down and lubricates the bottom between the — between the ground and the ice. Could this not be the same thing happening there?

Dr. SCOTT: No. You see, this is the thing, it would be much easier to explain the behavior of this glacier if we have that sort of mechanism, but it's just so cold here in this part of Antarctica that you don't get that. You don't get any melting on the grounded part of the ice that actually can get through to the land. In fact, you actually get very, very little melting if any even really to the surface of the glacier.

So, the immediate atmosphere around it is highly unlikely to be having an effect. Whereas on Greenland, warming of the air and the melting of the surface of the glacier certainly could have an — people think it's having a quite large effect at the moment.

FLATOW: So that's what is so puzzling then to you. Where would that slip-sliding effect originate?

Dr. SCOTT: Yeah. Well, it's a lot to do with possibly what's happening at the ocean side of the glacier. But also the base of the glacier is - where the ice meets the land is on probably some very soft wet sediments. And it could actually be that there's quite a lot of water underneath the ice, which seems strange. But the ice acts as an insulator so the geothermal heat can't escape, so it just sort of builds up at the bottom. Add the pressure of the ice in and you can get a lot of lubrication at the base of the ice stream.

And one interesting thing that they found recently is there is actually a volcano, a sub-glacial volcano, that's right next to this glacier. And last had a major eruption about 2,000 years ago. So, it's, in geological terms, still fairly active.

FLATOW: So it could be oozing underneath and we can't see it.

Dr. SCOTT: Yes. So, one of the things that we were doing while we were there was doing some deep-looking radar surveys, just look at the base of the ice to see if we could find out any signs of this going on, and some seismic survey show - using sound waves down to look at the strength of the base of the ice and the rocks, the rocks beneath it. So that's still pretty early days because I've been back from Antarctic for two weeks now, so - but hopefully, as we look through the data, we will find out more about this glacier and what is actually happening underneath it.

FLATOW: There's some theories about global warming that say that there might be an increase in snowfall in Antarctica where it doesn't snow a whole lot. And maybe - could there be an increase in snowfall and then pressuring the ice to move faster toward the ocean?

Dr. SCOTT: That's one possibility, but it doesn't seem that - and it could be a long-term instability in this area.


Dr. SCOTT: But it doesn't appear to be that. And the mass imbalance - that's the snow coming in compared to what's going out back into the ocean - it's definitely putting more ice into the ocean than it's receiving. And with the speed-up it actually seems to be increasing. So it doesn't seem to be - it just seems to be putting more ice into the sea. Whatever's happening with the snowfall that's replacing it.

FLATOW: A real mystery. Tell us what it was like camping out on the ice for months like that.

Dr. SCOTT: Well, it was a long time to be out there. We were there for three months, and we were about 800 miles away from our base which is called Rothera and even further away from there the U.S. Antarctic bases. So we're extremely remote, which is why we're the first people there since 1961. so we were just - the four of us there for about three months, and we each had a - we have two tents and we each had a Ski-doo so we can move camp and go up and down this glacier and do measurements at various places.

But, yeah, it's very remote and you have to keep yourself entertained, so we took lots of books to read in the evening and just worked really hard.

FLATOW: No surfing online?

Dr. SCOTT: No, unfortunately not. We had a satellite phone but the connection was too slow. So we just about managed to receive the old e-mail through it and that was the limit.

FLATOW: So you basically did all your work. It was all work and no play out there in the ice?

(Soundbite of laughter)

Dr. SCOTT: Yes. Yeah, mostly. But we did have an eight-day period where the winds were just so strong and it was blizzard conditions outside, so we were stuck in our tents for eight days and that was extremely frustrating. And…

FLATOW: Do you think about Robert Falcon Scott at all? What he must have gone through?

Dr. SCOTT: Oh, yes. Yes, it's - that's very scary. We tried to take enough food and few will have outweighed(ph) these days, so hopefully we don't find ourselves in those situations. But…

FLATOW: How cold did it get, the coldest?

Dr. SCOTT: We were there in the Antarctic summer so not particularly cold. It got down to minus 33 degrees Celsius, which is I think…

FLATOW: Pretty close to Fahrenheit, too. Yeah, pretty close.

Dr. SCOTT: Yeah, pretty close to that in Fahrenheit, which is cold enough when you're living in a tent. I can assure you that.

FLATOW: Well, we're glad you're back and warmed up, Dr. Scott.

Dr. SCOTT: Well, thank you.

FLATOW: Thank you for taking time to talk with us and good luck on your research. We hope you find out and report back to us.

Dr. SCOTT: Yeah, I hope I find something more interesting in the result for you. Okay.

FLATOW: Julian Scott, geophysicist at the British Antarctic Survey in the United Kingdom.

We're going to take a short break, come back, and talk more about something totally different - persuasive technology. How computers may be persuading you to take action. Stay with us. We'll be right back.

I'm Ira Flatow. This is TALK OF THE NATION: SCIENCE FRIDAY from NPR News.

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