Melting The World's Biggest Ice Cube

Jul 20, 2012
Originally published on July 20, 2012 12:55 pm
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This is SCIENCE FRIDAY, I'm Ira Flatow. Think of Antarctica as the world's largest ice cube. Ninety percent of the world's ice is locked up down there. But Antarctica is also home to one of the fastest-warming spots on the planet, the Antarctic Peninsula. That's the tip that points towards South America.

See a problem here? What happens when the ice in Antarctica melts? That's what one of my next guests has been trying to figure out by studying glaciers and ice sheets as they slide into the southern ocean. Some of the speed - listen to this. The speed of one of them is a foot an hour. You can watch this glacier move, as my next guest has, and he predicts that all that ice falling into the ocean will push up sea levels by two or three feet by the end of the century. That's - if it all melts, two or three feet.

If you live near the coast, you've got new waterfront property. Another effect of the warming you don't hear much about is the uncovering of microbes living inside and underneath the ice, billions of microbes that have been living in suspended animation, deep frozen for thousands, maybe millions of years.

Also there's melted water that might wake up whole communities of hidden life in Antarctica's dry valleys. Those are places that look like the surface of Mars. They're arid. They have no ice, but they have thriving food chains when the streams start to flow. How's all that going to change with a warming world? Is there any way to keep Antarctica a pristine place, safe from too much tourism, mining or pollution?

Those are some of the topics discussed this week at a meeting of the Scientific Committee on Antarctic Research in Portland, where all three of my guests were swapping stories. And if you'd like to swap stories with them, our number is 1-800-989-8255. You can give us a call, or you can tweet us @scifri, @-S-C-I-F-R-I, or go to our website and ask a question there at sciencefriday.com.

Bob Bindschadler is emeritus scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. He joins us from there. Welcome to SCIENCE FRIDAY, Dr. Bindschadler.

BOB BINDSCHADLER: Thank you very much, Ira, it's a pleasure to be here.

FLATOW: You're welcome. Diana Wall is a professor of biology at Colorado State University in Fort Collins. She's also director of the School of Global Environmental Sustainability there, and she joins us. Welcome to SCIENCE FRIDAY.

DIANA WALL: Thanks very much, Ira.

FLATOW: You're welcome. John Priscu is a professor of ecology at Montana State University in Bozeman. He joins us from there. Welcome back to SCIENCE FRIDAY, Dr. Priscu.

JOHN PRISCU: Thanks, Ira, it's good to be back.

FLATOW: Bob, let me start with you. Your talk at the conference was called "What Ice Sheets Hate." What do they hate?

BINDSCHADLER: They hate water, Ira.

FLATOW: Ice sheets...


BINDSCHADLER: Ira, water is a friend of life, but it's an enemy of the ice sheets, and there's a number of processes that we're understanding now, and they all - that are tearing the ice sheets apart, and they all lead us back to water as the culprit.

FLATOW: And where does the water come from?

BINDSCHADLER: Well, it comes from increased melt in some cases, melting on the surface of the ice sheet, but it also comes from water that's in the oceans already, that through the atmospheric changes going on deliver warmer water to the underside of these floating ice shelves, and ultimately that leads to a shrinkage of the ice sheet.

FLATOW: What's the connection between the two?

BINDSCHADLER: Well, between the atmosphere and the ocean and the ice sheet?

FLATOW: The shelves and the sheets.

BINDSCHADLER: Well, the shelves are basically - sometimes we call them corks in the bottle, but the metaphor I like better is they are valves that determine how fast the grounded ice sheet flows back into the ocean.

FLATOW: And as I mentioned before, there are ice sheets that are going at this unbelievable pace of a foot a day. Is that right?

BINDSCHADLER: A foot an hour.

FLATOW: A foot an hour, a foot an hour.

BINDSCHADLER: That's the Pine Island Glacier in Antarctica. It's about the fastest glacier in Antarctica. But in Greenland there are even faster glaciers, going four and five times faster than that.

FLATOW: And what's allowing them to move that quickly?

BINDSCHADLER: Well, gravity. Ultimately, gravity is what determines how fast the big pile of snow - you called Antarctica a big ice cube, and essentially it is, but it has so much mass, and the stresses are large enough that it's tilted slightly downhill, and it flows back into the ocean.

FLATOW: Is all that water, you said the enemy of it, is that also lubricating the surfaces to allow it to move that quickly?

BINDSCHADLER: That's right, that's another process. So if you have a warm summer, and you start melting the surface snow, you generate a lot of melt water. That makes the ice sheet smaller just by itself. But when that water gets down through cracks and actually works its way all the way down to the base of the ice sheet, it lubricates the base of the ice sheet, allows it to flow faster, so the ice sheet shrinks even faster.

FLATOW: Wow, let me bring in some other topics about Antarctica, one of my favorite places, because I visited it 30 years ago, or 33 years ago. Stuff has changed a little bit since I was there, but I do remember scientists talking about actually what would happen if the ice sheets were melting.

Diana Wall, you and a group of colleagues published a paper last week in the journal Science about the challenges facing Antarctica today. Tell us about that.

WALL: Yeah, we had a number of people get together and we looked at the short term, a 10-year period, and then out 50 years. And we said: What did see as scientists? And some policymakers were involved, but we've just said what are the threats. what do we see coming as threats?

And so what we see coming, you know, in the near term as the climate change impacts on marine systems and fishing, you know, increased fishing, ocean acidification, but one of the things that we're particularly interested in, in the terrestrial environment, and Antarctica has very little terrestrial environment, but where it is, it's - you know, it's been there a long time.

And so we're worried about these invasive species that we as humans may bring in because that's...

FLATOW: You mean people bringing stuff as visitors to Antarctica?

WALL: Yes, both scientists and tourists. You know, it's just more opportunities, as the ice melts, and some of the land gets uncovered very slowly, and we see more soil, more land, there's an opportunity there for this warming type of soil to have seeds that grow. So we're starting to see that in the islands surrounding Antarctica.

So invasive species, you know, that's one of our things.

FLATOW: Can you already see evidence of some species growing?

WALL: Absolutely. There's a new plant - a bluegrass that has been found, and hopefully we're going to eradicate it, but it has been found. There are also many different kinds of insects and other types of organisms that are found. Some of them haven't been established, but we know they've come because we tested - there was a paper recently that showed that they just basically took people and said what's in your pockets and what's on your Velcro as they came onto the continent.

And when they did that, they were able to look at the numbers of seeds each person, or other kinds of propagules like microbes and fungi, and say, OK, how much are you carrying? And they were able to quantify that for both scientists and tourists.

FLATOW: I think that's a real commentary on global climate change, is now for the first time you're worried about people bringing plants that could survive in an altered climate in Antarctica.

WALL: Yeah, I think it's remarkable because when I started working there in the late 1980s, I was pretty well under the dogma that it's too cold for anything from the outside to grow here. I mean, people have tried. You know, some of the early explorers even tried to, you know, grow potatoes and thought that would be a great place for potatoes, but they didn't work.

FLATOW: 1-800-989-8255. John Priscu, you're a microbe hunter, and you have found lots of interesting stuff living in the ice in Antarctica. Tell us about what's living in the ice and how it can survive there and what's going to happen now if some of the ice sheets starts - or is melting and warming up.

PRISCU: Right, Ira, if I could follow up from what Bob was talking about, bugs - or the ice hates water, well, the bugs love water. So it's just the opposite here. And you were there 30 years ago. Things may look a bit similar, but we know a lot more.

We now know that the underside of the ice sheet is really wet. There's over 200 lakes, some of the largest lakes on our planet, Lake Vostok being the largest under Antarctica, it's the size of the North American Great Lakes, and over 1,000 meters deep. So these are - these weren't known 10 years ago to exist. They were still at a speculative state.

We now have strong evidence that they harbor unique ecosystems under the ice, and we've published papers calling the underside of the ice sheet our planet's largest wetland. We're not going to see redwing blackbirds or cattails, but it's a microbial system that lives much like the deep sea vent systems, in the dark.

They mine rocks for energy, and they change the chemistry of the underside of the ice sheet, which then flows out. We heard talks this week about these river systems under the ice sheet flowing to the ocean and fertilizing the southern ocean.

So we now look at the ice sheet, instead of a large benign ice block that - with various geophysical dynamics, we now have to look at it as part of the Earth's biosphere and include it in calculations of carbon, global carbon and global biodiversity.

FLATOW: So you have sort of an inland sea with the rivers flowing out of it unseen. How big are the rivers?

PRISCU: Yeah, exactly. Some of these rivers are - the river basins, the drainage basins are the size of the Amazon River. Antarctica is a big continent. There's a lot of real estate. And so there's these major river systems draining the highlands out to the ocean through a series of lakes.

FLATOW: Does that mean that the locked-up bugs in there are now finding new homes in the oceans?

PRISCU: Well, that's a great question. We have a - we like to call - people in my circles like to call the Antarctic ice sheet the largest ice museum that exists on our planet. It's a museum of DNA that has been isolated for up to a million years if not longer. So we have a history of bugs that go back on Earth a million years that have been entombed in ice that are going to eventually, as the ice retreats, be introduced into the southern ocean.

And we haven't a clue what they'll do to biodiversity, or people have speculated that we may introduce past diseases that have been entombed in the ice as the bugs, but we don't know.

FLATOW: Wow, something to think - we'll talk more about - this is fascinating. Bob Bindschadler, Diana Wall and John Priscu, 1-800-989-8255 is our number. We'll talk about the waters that are melting in the Antarctic, what's happening, what they influence, where are the bugs going, what they may be doing. Stay with us, fascinating stuff. We'll be right back after this break.


FLATOW: You're listening to SCIENCE FRIDAY, I'm Ira Flatow. We're talking this hour about Antarctica, its melting ice sheets and the microbes that live with them and how they are - some of them may be escaping out through the rivers underneath, hidden, giant, inland, under ice seas that - some of them as big as the Amazon River.

Bob Bindschadler is emeritus scientist at NASA's Goddard Space Flight Center in Greenbelt; Diana Wall, professor of biology at Colorado State University; John Priscu, professor of ecology at Montana State University in Bozeman. If you want more about Antarctica, we've got plenty of great photos up on our website. If you want to see what I was doing there 33 years ago, there are pictures of me. Just look for my frozen face at the South Pole over there on the left side of the website, click on that, and it'll take you to our collection.

Let's talk - and Diana Wall, let's talk a little about the dry valleys, interesting place. I actually visited them. They look like an anomaly because there's no ice there.

WALL: No, it's very much like I would imagine landing on Mars and looking around. It's a huge area that's a desert, and so it's been fascinating to me to look at how these hidden animals and microbes change as we start warming the soil there.

FLATOW: And what happens to them, as let's say some of the liquid water gets to them?

WALL: Well, as spring comes, and they get some liquid water, they - they're - it's like they've been in a freezer, and all of a sudden they start to rehydrate, they change their physiology, and they take on a much more active state. They start - the ones that I work on are tiny microscopic roundworms, and they live in the soil, and you wouldn't see them, but they're quite fascinating under a microscope.

Those guys start feeding on microbes and reproducing, and they have a physiology, but if it gets towards winter, they start desiccating, again going - getting ready to go in the freezer, and just kind of shut down their metabolism, and they're pretty well in a non-metabolic state until the next spring.

FLATOW: Wow, and so what do they do? Do they come out of hibernation and start doing what?

WALL: Well, they come out of - they eat first.


FLATOW: What are they eating there?

WALL: They're eating soil bacteria. They eat some of the algae that are - there are melt streams that kind of intersect of bisect the valleys, and those melt streams contain algae. So there's enough water there to support them. And those streams carry down into the valley floor, where there are frozen lakes that John Priscu studies, for example, and studies the cyanobacteria.

And so underneath this lake ice - there's a permanent ice cover on the lake that's in the valley floor, and beneath that are cyanobacterial mats.

FLATOW: Wow, yeah. 1-800-989-8255. Could there be uncovered, undiscovered species of all kinds of life down there?

WALL: Oh, I absolutely think there's - we haven't even tapped it. A number of us were fortunate enough to go farther south to some of the nunataks, the little mountaintops that are uncovered by ice, and we were able to go south, and we looked at some of those mountaintops that are largely just - not very much is exposed outside of the ice sheet.

And we found a lot of biodiversity there that we hadn't expected. We would have expected it, as you get colder towards the South Pole, to have nothing living. So we found species of nematodes, mites, little microarthropods that are hidden in the soil. We found some other types of microarthropods.

And of course lichens were growing on the sides, so a big diversity that just hadn't been looked at before.

FLATOW: And where do you think they came from?

WALL: Well, the current theory is that some of these what we call nunataks, these mountain peaks, didn't get totally covered during the glaciations and so that they're kind of refugia for organisms. They just kind of held on and were desiccated there through some of this - the ice, the glacial ice, and now that - they're growing - very much like John's - very much like the comments John Priscu was making about having the hidden biodiversity on the underside of the Earth, there's still - on the underside of the Earth, the ice sheets, there are still some organisms that are sitting on those mountaintops waiting for water.

FLATOW: Wow, could they have been blown in or come in on some snow somehow?

WALL: It's very possible. The - but they need to colonize and find their mates to reproduce and to keep - you know, they need some carbon to keep growing. And so we can look at the genetics between, for example, some of the nematodes that we found at 84 South and compare them to the dry valleys and then compare them to even, you know, farther northern ecosystems, and they pretty much look all the same. So it's very possible.

FLATOW: Bob Bindschadler, you were talking about the Pine Island Glacier moving about a foot an hour. Are all the glaciers in Antarctica melting at that rate or moving at that rate, or is this something unique?

BINDSCHADLER: For Pine Island, it's unique in its speed, but Antarctica generally is drained by a number of outlet glaciers like Antarctica. So the snow gets funneled from the deep interior, where it moves very slowly, and it accelerates as it gets - as it coalesces into these fairly narrow channels and then flows faster and faster as it approaches the coast.

FLATOW: So might there be other giant hidden lakes there also?

BINDSCHADLER: Yeah, as John said, there are over 200 that we know about, and so we can only see the medium and large-sized ones right now. And one of the ways we detect them is by measuring the fact that the surface goes up and down. So there could be lakes that aren't changing that are much more difficult for us to detect.

And the really interesting thing for me as a glaciologist, when John starts talking about the interconnectedness between the lakes and the rivers underneath the ice sheet, is the fact that not all of those rivers are there all the time. The ice squeezes them shut, and it's only when a lake drains that the river actually opens up because the water melts its own channel.

And in some cases these rivers will flow uphill because it's actually the shape of the ice sheet that determines which way the water will flow in one of these channels. So it's not certainly a simple lake and river system that your listeners would be accustomed to. It has an extra little twist to it, where a lot of the water is flowing back uphill and actually refreezing onto the underside of the ice sheet.

FLATOW: John, it would be fascinating if you could make some sort of map for us of all those lakes and rivers under there.

PRISCU: Well, certainly that's an activity that people are working very hard on, is to get a better picture of it.

FLATOW: Yeah, it's quite - and Bob, you agree? It would be great to have a map of...

BINDSCHADLER: Oh, absolutely, and we have maps. We're making maps, and we're making the maps better as we continue to look at it and as it continues to change, because as it changes, that allows us to detect even more of what's there.

FLATOW: John, earlier this year the Russians drilled all the way down to Lake Vostok - we talked about that a little bit, under the ice sheet. Have they found anything living down there? And is that a good thing?

PRISCU: Well, their project on February 5 of this year did penetrate Lake Vostok, and we actually saw a movie of the actual penetration. We saw that two days ago, presented by the head of the Russian program. But their plan is - they didn't bring up any samples in the February drilling season. Their plan is to go back next year.

Actually, when they did penetrate 500 meters of water, came up into their borehole, their borehole is almost 4,000 meters deep, so it's over two and a half miles below the surface of the ice, these lakes. So they let water rise up the hole, which will then freeze in over winter. As we speak now, that water is freezing.

And they plan to go back next December and January and re-bore that ice, and that will be their lake sample, is the water that's come up the hole. They haven't put anything in the lake to actually collect samples.

FLATOW: But leaving it open like that for - doesn't that contaminate the sample, if it's exposed to the air and the ice above it?

PRISCU: The ice will - it will freeze. So the lake is still capped. You know, our big issue - I think the issues that the Russians will have actually will be contamination of the actual sample itself because it's come up into a kerosene-based drilling fluid. The lake water has risen up and mixed with this drilling fluid.

And our experience working on such systems in Greenland have indicated that that's not a good thing for sample integrity. So they'll have to sift through those samples and figure out what is a real sample, a clean sample versus contaminated sample. So they have a long road ahead.

There are two other programs that will penetrate for the first time, lakes in Antarctica. The United Kingdom will be sampling over in West Antarctica a lake, Lake Ellsworth, it's under about 3,500 meters of ice. And the United States will be sampling lakes under the Willens(ph) ice stream; that's one of these fast-moving streams that actually Bob Bindschadler has one named after him because of his studies in the past.

And so we'll be sampling lakes that are very active lakes, with a lot of water flowing through. So next year is going to be a real - a milestone year for subglacial research.

FLATOW: Is the melting that's going on in Antarctica sort of a ticking clock for you researchers who want to get to see the ancient preserved ice down there?

PRISCU: Well, I think the melting that's going on - as Bob indicated, I think one of the real important factors of this is, as he said, is the ice does not like water. And as the water is melting, surely, you know, it's providing habitat for microorganisms. But it's also lubricating the bottom of that ice sheet and making that ice flow to the ocean, to the sea faster, and that's just one little intricate component of ice movement. But I think that's a - so whereas the water is good for the bugs, it's not good for ice loss.

FLATOW: Is it melting all over Antarctica? It's a big continent; it's as big as U.S. and Mexico put together. Is that generally true all over the place?

PRISCU: I'm going to defer that one to Bob.

FLATOW: OK, Bob. Bob Bindschadler.

BINDSCHADLER: In Antarctica it's not melting all over. Most of the ice sheet does not experience melting even during the height of what we call summer down there. But it is melting quite extensively on the Antarctic Peninsula, and you mentioned that, Ira, in your introduction. That's a place where the vast amount of melt that is taking place is tearing these ice sheets apart through another process that water utilizes to shrink the ice sheets.

And that's just what we call hydrofracturing, filling up crevasses. And essentially because water is heavier than ice, it forces these cracks all the way through the ice, chops it up into tall pin(ph) dominoes, basically, and then the ice shelf just disintegrates, is the term we apply. And then that opens up the valve, and the glaciers that took thousands of years to form those ice shelves begin to accelerate. And that adds water to sea level, globally.

FLATOW: And does that fracturing, does that move backwards, southward toward the central part of the glaciers, the central part of the ice sheet?

BINDSCHADLER: That's right. We've been looking at this over the last 30 years, and we see a southerly progression of disintegrating ice shelves, just marching its way south along the Antarctic Peninsula. And what awaits it in the main part of the ice sheet are some really, really large ice shelves that generally have not experienced summer melt. There's been the occasional summer that once the melt gets extensive on those very large ice shelves, things could change very quickly in a very dramatic way.

FLATOW: This is SCIENCE FRIDAY from NPR. Is there a reason to believe that that will be happening?

BINDSCHADLER: Yes, every reason in the world. We know the trajectory that we're on right now, with the increased warming in the planet, Antarctica has been keeping itself a little bit cooler than average. But there's - we know now that it's warming there as well. And this is probably - we're getting an early look into the actual processes by which the ice sheets always shrink when the Earth's climate gets warmer. We have a million years of climatic evidence from ice cores and deep-sea cores and coral cores that says every time the world gets warmer, sea level goes up because ice sheets shrink. That's the trajectory we're on.

FLATOW: Sarah(ph) in Staunton, Virginia. Hi. Welcome to SCIENCE FRIDAY.

SARAH: Hi. Can you guys hear me?

FLATOW: Yes. Go ahead.

SARAH: Awesome. I'm actually a student doing research on glacial meltwater right now, but I focus more on Greenland. I was wondering if Dr. Bindschadler could actually - might be able to elaborate on some of the differences between the dynamics of Antarctica and the dynamics of Greenland. And I'll take my answer off the air.

FLATOW: Thank you.

BINDSCHADLER: OK. So I just go ahead and answer it now?

FLATOW: Yeah. Go ahead. Sure. Just jump right in.

BINDSCHADLER: Yeah. Well, Greenland is more susceptible to changes in what we call its surface mass balance. So how much does it snow? How much does it melt? The dynamics around the edges appear to be quite important.

But the difference between Greenland's response to those changes in the environment, those types of changes, and the ones we see happening in Antarctica is that in Antarctica it seems to be mostly about what's happening with the ice shelves, these valves around the perimeter of the continent. How fast are they allowing ice to go back into the ocean, and what determines how open these valves are is how much melting is going on underneath the floating ice shelves.

So Antarctica has these big floating ice shelves. Greenland may have had in the past, but it doesn't have large floating ice shelves.

FLATOW: Yeah. Quick question from Darla(ph) in Provo, Utah. Hi, Darla.


FLATOW: Hi there.

DARLA: Thank you for taking my call. I listen to you all the time. I'm hearing about all of the negative ramifications of what's happening in Antarctica. I'm wondering if you can address maybe the flipside of that with these microbes and things that are going to - we're going to be introduced to, possibly, that have been out of our system for years. You know, they could have all these diseases, but what about the cures that they might hold...


DARLA: ...or, you know, the positive things that could come from it?

FLATOW: Good question. Diana Wall, can you answer that?

WALL: Yeah. I think this also refers to something that John had said, that as some of these organisms are uncovered, we may find that they are beneficial. And as Darla suggests, it could be a microbe that would be useful for curing something, or it could be a microbe that would have some part of its gene that we could use for a very flexible climate, you know, and be able to have a bigger tolerance for various temperatures. We don't know what we're going to find with these new microbes that we'll be seeing.

FLATOW: Has anybody - can you go to the melt-off and just collect it with buckets and stuff like that to see what's in it?

PRISCU: Maybe I should...

WALL: John, you better answer that.

PRISCU: Yeah, this is John here. And Darla, yeah, that's a great question. Let me - if I could...

FLATOW: I've got about a minute, so go ahead.

PRISCU: Oh, OK. We've - I'll make this quick. We are finding unique organisms just in our core samples. A lot of them are psychrophiles. It means they're cold-loving. And also, they can withstand freezing (unintelligible). And I have been contacted by cosmetic companies, thinking there's a compound in them that they might be able to use as a, you know, in a cream that keeps you looking young or things of that nature.

So these are unique organisms, and we don't see them in the temperate regions. So I think there will be pharmaceutical and other industrial uses of these organisms once we start sampling them.

FLATOW: Well, good luck to you all, and we'll have you back when you make more discoveries. Bob Bindschadler, Diana Wall, John Priscu, all researchers in the Antarctica. We're going to take a break. When we come back, we're going to have Sylvia Earle join us from the bottom of the sea, live from underwater. So stay with us, we'll be right back. I'm Ira Flatow. This is SCIENCE FRIDAY from NPR. Transcript provided by NPR, Copyright NPR.