Project Save the World Podcast / Talk Show Episode Number: 284
Host: Metta Spencer

SUMMARY KEYWORDS

ice sheet, antarctica, glaciers, icebergs, curtain, people, greenland, ice, melting, warm water, ice shelf, antarctic, glacier, ocean, flow, engineering, deep, troughs, benefit, water

SPEAKERS

Peter Wadhams, Paul Beckwith, Metta Spencer, John Moor

Synopsis: Roald Sagdeev led scientists in Gorbachev’s USSR; Frank von Hippel was his counterpart in the US. They worked together to reduce the risk of nuclear war.

Please note this transcript has been edited. 

Metta Spencer  00:00

Hi, I’m Metta Spencer, Well, should we go to Greenland? Or do you want to go to Antarctica today? You get your pick, because we’re going to try to save some ice. It seems that the ice cover of Greenland and Antarctica has been melting way too fast and we have to do something about it. So, we have today a conversation between specialists on this topic. There’ll be a third person joining us in a bit. We’re going to talk about how we can keep all of that ice from melting and running off into the ocean. The person who thinks he knows how to do that is John Moore, who is based right now in Lapland in Finland, and normally teaches at a normal university of Beijing in China, where he was directing a program of geo-engineering. And he sounds sort of Canadian with a British accent. I don’t know. Where are you really from, John?

John Moore  01:55

I’m from Britain,

Metta Spencer  01:56

I thought there was a little British in there. Well, you got another Brit here with you. And that’s Peter Wadlow. He’s not in in Britain, either. I think he’s in Turin, Italy, aren’t you, Peter?

Peter Wadhams  02:09

Yes. I left for the past three years. Ever since Brexit.

Metta Spencer  02:20

Good thinking! Peter Wadhams is a professor at Cambridge University, but he spends a lot of time climbing around on the glaciers in Greenland. And I think he’s also seeing some glaciers out his window in the Alps of northern Italy. Isn’t that right? Yes. Well, now the thing that intrigued me was that somebody sent me a copy of a column by Gwynne Dyer, a wonderful journalist that I’ve met several times in the past and like very much. He wrote about an innovation – or at least a proposal for an innovation – by, I think, John Moore. I’m going to ask John Moore to tell us how you propose to save the ice and keep it from running off from Greenland and Antarctica. Please give us a little preview of this and then I will ask Peter what he thinks.

John Moore  03:32

Okay, thank you. I will just introduce the idea with a few slides. So this was the start of the idea. Everybody has probably come across these kinds of curtains that are used to separate rooms with different temperatures, like a cold room or something like that. But you can go in and out with a vehicle or walking without needing to open the door. And this is how it would work, actually, in the ice sheet. So you have a glacier. And you have a curtain that’s anchored with concrete at the base to the sea floor and floating in the water column. And the interesting thing is that the ocean is stratified, and the warm water is at the bottom rather than the top because it’s salty. So it’s very heavy. 

So you have a glacier and of course it’s it can calve icebergs. We want something that is flexible, like a tree branch or something. It’s not destroyed by any physical thing. So yes, an iceberg can come along and push this curtain aside. And after the iceberg is gone, it springs back into its original position. 

Now, why this works is that the ice sheets – I’m talking about Greenland or Antarctica – lose ice, mostly through narrow outlet glaciers that are incised deeply into the bedrock. And if you can basically put the plug back into the, into the bathtub, which is the ice sheet, it’s a lot easier to keep that water in the bathtub than constantly filling it up with a watering can. And so, this is the idea: that you would have leverage by applying an intervention to perhaps a few percent of the entire coastline of Greenland or Antarctica, where most of the ice is flowing out, and which is the most susceptible for catastrophic loss of the ice sheet. So, you have enormous leverage by focusing on these particular areas. The kinds of material that we would use are rather similar to what’s called geo-textiles that have been used in buildings fairly commonly for a long time. Now, for example, there’s a material called high modulus polyethylene, which is 15 times more resistant to abrasion than steel. It’s effectively inert in water, and very low coefficient of friction. 

Metta Spencer  07:10

That’s what you’re going to make these curtains from?

John Moore  07:14

Yes, that’s right. So, you have a concrete foundation. And then you have this plastic thing. There’s no structural strength, this is not holding back the ice sheet. This is simply slowing the melting by blocking access,

Metta Spencer  07:29

And you hold it in place with balloons or something that can easily be pushed aside.

John Moore  07:36

Exactly. Not balloons but, for example, fiberglass pipes that can be filled with air. They supply a lot of buoyancy and have tremendous tensile strength. So where would we do this? We wouldn’t need to do it all the way around Greenland, all the way Antarctica. You focus on the particularly vulnerable areas. On  this map here you can see highlights in red. Those areas are losing mass rapidly in Antarctica, and in fact, it’s confined to a handful of glaciers in this sector called the Amundson Sea around here. And if we zoom in in this box, we can look at the flow speeds in red and blue – fast-flowing glaciers. The key areas are Pine Island and Thwaites glaciers. People may have heard of Thwaites glacier; it’s been called the Doomsday Glacier in some articles because it’s actually on bedrock that is below present sea level,so, if you remove the ice sheet, you wouldn’t have a continent. You’d have a few islands poking out of the sea. That’s an unstable configuration for the ice sheet. We’ve got the continental shelf here, the deep ocean, and the continental shelf actually gets deeper as you go inland. These blue colors are deeper than this kind of yellow.

Metta Spencer  09:27

Excuse me. Now this yellow area, that’s still ocean, right?

John Moore  09:31

Yeah, this is the sea floor.

Metta Spencer  09:35

On this map, where’s the edge of the ocean? Where’s the land?

John Moore  09:40

Well, this is the coastline. We’ve got the glaciers in white, and the floating parts of the ice shelves are in this kind of translucent color here. Yes, and so this glacier over here and Pine Island place here, up here.

Metta Spencer  10:06

All of the colored area is underwater?

John Moore  10:10

That’s right, the whole colored area’s underwater. It’s been mapped by ships and sonar and submarines that can go under the ice. So, what people have found only very recently is that the warm water that’s flowing on the bottom, as I said, because it’s very heavy and dense with salt, that is largely confined in these troughs. And they are relatively narrow. These pink arrows show the warm water pathways underneath the floating glaciers, ice shelves to the parts where the glazier goes off the land and starts to float. So, if you can somehow stop that warm water in these deep troughs, from accessing underneath the glacier, you will slow down the rate of melting very dramatically. So now, if we have a look at cross-sections, through these warm water pathways, when you’re outside, when you’re far away from the from the ice out here, in the continental shelf, it’s quite a sandy bed, you could say, quite smooth topography, and these troughs, of the order of 50 kilometers across, something like that – 50 to 100 kilometers. The closer you go to the ice, the more sharply incised the bedrock topography is. But that means that the warm water is confined in narrower channels. 

And you can see that if we zoom in again, on this area here, what people call Trough Two is only four-and-a-half kilometers across. And this is the warm water pathway that is melting the most vulnerable ice shelf on the planet. So, this is something that would seem to be a target for potential intervention. You gain this massive leverage I talked about, where you’re putting the plug.  This is the plug hole, basically, that we want him to try to fill. There are other pathways. It’s not necessarily clear that if we blocked just Two, you would solve the problem. I’m not saying that, because maybe the warm water would find another pathway – maybe this T Three. If that’s the advantage of pulling a curtain further out, you would protect more of the glacier. It would be more challenging from an engineering point of view, but you would get a bigger benefit in terms of the ice that’s protected. So, if this trough over here, you would protect Thwaits and Pine Island, and a number of these smaller glaciers as well. So, this kind of summarizes the idea. You have this warm water, you have a sea bed curtain over here with reinforced tensile fabrics and variety of different kinds of foundations. We’ve looked at it.  I won’t go into detail now about all of these details. We’ve made engineering models about how the forces would be on this curtain. We know the kinds of materials that would be needed. We’ve also argued that there’s a duty of the signatories to the Antarctic Treaty System to proactively protect the ice sheet. Things like the Madrid protocol govern the preservation and the maintenance of the status quo. But if people did not do active conservation, effectively, the ice sheet would disappear relatively quickly because of these greenhouse gas emissions. So, there’s this kind of moral – and actually arguably legal – imperative to act.

Metta Spencer  14:37

May I ask one question here? I’m not sure where the warm water comes from. Is it that the ocean in general, all over the world, all the ocean has the cold water at the top and there’s warmer water at the bottom?

John Moore  14:55

No, the warm water is, in ultimate terms, generated in the tropics. That’s heating the global ocean.  93% of the incoming radiation rises due to greenhouse gas, 93% of that energy has gone into the ocean, and it’s heating the ocean. That’s been going on since the Industrial Revolution. That’s why it’s very difficult to do anything about it. It’s this huge amount of energy that’s stored in the ocean. Now, on this figure here, you see this blue, this deep blue that’s at the edge of the Antarctic continental shelf? The waters there are cold by normal standards, but warm by the standards of Antarctica, which of course, is in contact with all of this ice and those deep waters, heated by the atmosphere way up in the tropics, those contain a lot of energy. And they are periodically kind of pumped onto this continental shelf by climate, by weather variability. And those warm waters flow over the continental shelf through these deep, deep troughs. And that’s something that has increased since the early part of the 20th century. We know there’s a lot more warm water being pumped onto the continental shelf than there was 50 years ago, for example.

Metta Spencer  16:47

Well, I’ll be quiet and let Peter – 

John Moore  16:50

I can’t finish this?

Metta Spencer  16:56

I beg your pardon. I thought you were through.

John Moore  16:58

No, I’m just going to point out that when we cost this, we look at who would benefit. So, we estimate there’s roughly 200 million people that would be forced to move by the collapse of Thwaites glacier around the world, because their living conditions would become untenable in terms of flooding. And you will have a knock on effect. If you remove ice in one base, you’re lowering the ice sheet, and that will tend to destabilize surrounding basins as well. So, the costs of doing this are something like $5 per person per year for those 200 million people, so we’re looking at something like $50 billion for the construction, and about a $2 billion – one to $2 billion per year  – maintenance cost for periodic replacement of these curtains and foundations. 

If you compare that with things like the Stratospheric Aerosol injection, which costs at the order of seven to 70 billion, depending on how much protection you would need to do for the, for the temperature rise. So, and

Metta Spencer  18:29

With a stratospheric injection, you’d be talking about this 70 billion indefinitely, not just as setup, right? So, 

John Moore  18:39

Well, for perhaps at least 100 years. You know, it takes time to remove the CO2 from the atmosphere by afforestation or artificial trees that you could somehow lower the CO2 concentration and store it long term in rocks. Yeah. And coastal protection.

If you said, pkay, we won’t stabilize Antarctica. We will just pay for berms and dikes and things like that, which, sure the rich part of the world could do,  the developing world is much less able to do. And that’s estimated to cost about 50 billion per year. So, it’s probably 50 times more expensive than this intervention that we’re talking about, for the Antarctic. 

So that’s basically the overview. There’s a ton of details that I have not gone into but, by all means, let’s have a discussion about it. I would say that we are not planning to go straight to Antarctica. We are at the moment working with Greenlanders and in Greenland trying to do some kind of a learning experience to explore how would Greenland feel about protecting its ice sheet. What benefits to Greenlanders are there from doing this kind of work, if any? Perhaps they don’t care.

Metta Spencer  20:13

Fascinating. Thank you. Okay, let’s turn this off and let’s see what Peter has to say.

Peter Wadhams  20:24

Well, first thing is, I can see that this vertical barrier concept is a good one because it’s been already thought for another project, which is preserving icebergs and towing them around to places which need water. So, there’s a project to take icebergs from Newfoundland, tow them to Tenerife, which has got zero water, by having a geotextile and vertical barrier, and woven fabric. It’s the same fabric as is used to preserve ski lands in the Alps. And that then surrounds the iceberg close in, so that it’s more or less like a wetsuit, and the layer of water between the iceberg and the fabric is warmed by the fact that it’s close together and this was not warmed. Actually it’s preserved and that keeps the iceberg from melting quickly when it’s going being towed through warmer seas. And the effect seems to be great enough that you can in fact get at least two-thirds of an iceberg from Newfoundland to Tenerife. So okay, that’s, that a similar concept. It’s not quite the same, but it’s the same idea – that you’re using a vertical barrier to prevent heat flow to vent heat. And I’d be happy to do that and to see that being deployed. It could very well be useful. The only thing that concerns me – because I I haven’t worked on the spacecraft series – is, a bit like Metta, I sort of wonder where does the warm water come from? Because all the glaciers and ice sheets that I’ve looked at have got the warm water above cold water. So you’ve got to have a source of warm water right down at the bottom of the ice sheet. I’m wondering, where does that come from? And how is the flow of warm water preserved?

John Moore  23:42

Okay, well, you know, it’s interesting what you said about geotextiles around the icebergs. But we do know that in reservoirs, they do use curtains of about 100 meters thickness to separate warm and cold waters for the ecological benefits downstream for salmon habitats, for example. So, in a sense, that’s a surface floating rather than a bottom anchored. There is warm water when looking at these temperature salinity profiles that are available from the area and also in Greenland, in for example, Disco Bay. In the summer, the surface layer 100 meters or so certainly does warm up. But over the longer term, the deeper waters are warmer than the surface. I’m talking about 500 meters deep and deep at the thermocline – this temperature change where you get this increasing temperature – is quite deep in the Amundsen Sea sector. I can say usually it’s been between about 500 to 700 meters deep. So that’s why these troughs, which can be up to 1000 meters deep – they are very deep troughs. Those are where that inflow of water from outside Antarctic is coming in there. 

Obviously, the deeper the trough, from the engineering point of view, the more difficult it is to work. So, the things that we’ve looked at are how the costs change. Or how do they scale with the height of the barrier above the seabed, with the length of the barrier, and the depth that you’ll have to work out? So, we did a kind of a cost-benefit analysis where we guess the costing compared with the amount of ice in terms of sea level that is protected by these barriers. Then you can estimate what height is the best to have the top of the curtain at. And without fairly crude color and cost-benefit analysis, it’s about 550 meters. So, we’re not going really anywhere near the upper part in the Amundsen Sea sector. 

In fact, the icebergs that are calving from Thwaits and Pine Island are less than 500 meters deep. So probably they would mainly go completely over the barrier without even hitting it at all. But yes, where the glacier comes off the land, it’s 1000 meters deep. So that’s how the warm water is melting rapidly at the base.

Peter Wadhams  26:48

Well, is that process something that’s changed over the years? Or is it continuous or discontinuous? Because that would surely get rid of the Thwaits glacier here in pretty short order.

John Moore  27:06

Yes, you’re right. And if you look at the pictures of the the Western Thwaites, I it’s in terrible state. I don’t know that anyone’s got a real solid estimate of how long it would survive but I think some alarming estimates are as little as five years. Ice shelves are notoriously difficult to predict their lifespan. They can disappear virtually overnight when they go. But certainly, there’s a lot of damage there. You can see that the shear margin where the edge of the glazier is flowing very rapidly. It’s very chaotic. Looks very weak. You could say it’s being torn apart; it’s tearing itself apart and accelerating. And this is something that seems to have happened in the early part of the 20th century, maybe 100 years ago, maybe 80 years ago. At least it seems to be related mostly to the tropical Pacific, to the heating in the tropical Pacific that finally makes its way down to Antarctica. It’s not so much the local sort of Southern Ocean circulation or the atmospheric circulation around Antarctica that’s driving it. It is more a global ocean sort of driving force there.

Peter Wadhams  28:47

So do you have estimates of how fast the melt is going? I mean, that is left to itself? How long would it take before the glacier here is significantly degraded?

John Moore  29:07

Yeah, we have one critical thing: the buttressing, that’s really the key thing. How much back force, the ice shelf where it’s grounded, is supplying to the inland ice? So, the amount of buttressing depends on how rapidly the ice shelf can calve away into icebergs, and that is one of the classic deep and unknown issues in glaciology. A good calving relationship. People have done very nice, high resolution models that require enormous computer power to solve. Cracks propagate at the speed of sound. Glaciers flow very, very slowly. This is a super-difficult computational problem because you’re trying to span so many different scales of velocity that it’s difficult to do. But we’ve looked at different formulations, different kinds of calving, and you get rapid retreat downslope of the Thwaites Glacier over the next hundreds of years and it continues for quite a long time into the future. The speed at which that glacier retreats is still very difficult to say, though,

Peter Wadhams  30:37

That will be really a question. Is this some kind of emergency or not? There’s a –

John Moore  30:46

Yes, I would say that we could handle this, basically, reasonably well over the next 30 years. The longer you leave it, the more difficult it is. It’s like a ball rolling down a hill. If you do it at the start, of course, it’s easy to stop, the more speed it’s got, the more momentum the more difficult it will be.

Metta Spencer  31:16

Didn’t you say a while ago that the Thwaite Glacier might collapse within five years?

John Moore  31:25

That’s not my opinion. But I’ve certainly read articles that say that. That give timescales. So, it’s, as I said, it’s very difficult to know how quickly it will go.

Metta Spencer  31:38

So if you’re starting a project that’s going to take 30 years, but within five years, it’s already failed – I don’t know? This doesn’t sound too easy to sell people on. 

John Moore  31:51

Well, the thing is that, even if the ice shelf disappears, it can come back. The point is that, if you stop that warm water coming in, and you turn off the melting from rates around 100 meters a year to 10 meters a year, or even zero. That ice, coming off 1000 meters thick from the land, isn’t going to be thin very quickly. It’s going to stay thick, and the ice shelf is moving rapidly off the land. So it will very quickly grind on to these seabed highs again. Of course, we don’t know for sure. It’s certainly easier if the ice shelf is still existing while you are trying to do this kind of an intervention. And if it’s disappeared completely, we want to keep the thing as close to the status quo as possible. But the point is, if you’re slowing down from 100 meters a year to one meter a year or zero, you’re gonna get a difference.

Metta Spencer  33:03

Okay. Here we are being joined by Paul Beckwith. Hello, Paul, how are you?

Paul Beckwith  33:10

Hello, Metta. Sorry, I couldn’t make it right at the start. But I’m here now.

Metta Spencer  33:15

You’ve missed a slide show. John Moore here has been showing us pictures of Antarctica. Do you want to do a quick quick quick replay of that slideshow and show Paul what we have already been looking at at greater length?

Paul Beckwith  33:38

Thank you. That’s okay. I can just sort of listen to you guys for a few minutes. I’m sure I have a few comments to make. Okay.

John Moore  33:46

Yes, if you have any questions and I can maybe show the relevant slide to explain the concept. So where were we?

Peter Wadhams  34:00

Yeah. Firstly, this phenomenon of warm water underlying cold water, which is obviously going to lead to an unstable situation, and how long that has gone on for, and whether it will carry on like that, and whether that’s going to be the root cause of the disintegration of the ice shelf. Some big questions really.

John Moore  34:28

Yeah, well, as you know, Peter, there is a plume of fresh water that comes out from the base of the ice because most of the Antarctic is at the melting point. So, this comes out of a kind of a sub-glacial river, and that pushes out under the ice shelf. And as this flow, this river, is coming out, it’s entraining the warmer ocean waters within this plume. And those warm waters are the things that’s causing the rapid melting underneath the ice shelf. As those warm waters are brought up by this rising plume, then they are cooling. Of course, they’re melting the ice. Eventually, there’s a compensatory flow outflow of this cold water at the surface or near the surface – let’s say in the 100 meters depth – that is replenished by this deep flow off the continental shelf of waters that are this global ocean. Deep waters which are relatively dense because they’re at the bottom of the ocean, and warmer than these waters that have been freshened and cooled by contact with the ice. And

Paul Beckwith  36:10

This warmer water is also more of a problem when the bottom is sloping, not towards the ocean, but sloping inland, right? In the warm water, when the glacier starts receding, then it has to move back a long distance, right? James Hanson, have you talked about some of his work? Because he was talking about the warming waters around Antarctica in papers many years ago. And, you know, even a few years ago, he’s had some major papers on how this is a factor that is not included in the climate models. 

People still talk about ice on Antarctica lasting thousands of years, right?  I’m always amazed that when I hear that sort of thing. NASA has, interestingly, started to do some Facebook posts – people with different groups at NASA, where they’re presenting data. And just yesterday, or even this morning, I saw a number like that: it’s still going to take 1000 years or whatever. No matter what type of warming there is, you know, the Antarctic ice is going to be there for an awful long time. I don’t know how they can say that. Actually, I’m always surprised.

John Moore  37:59

Some parts of the Antarctic – a lot of the Antarctic – actually is relatively stable. So that means, sure it will melt, but it takes time. Like surface melting from the top downwards. It’s very difficult to get more than about a metre a year, because the air is not such a very good conductor of heat. Of course, it’s actually –

Paul Beckwith  38:23

It’s heat capacity is low. And also, ice is a very good insulator, right?

John Moore  38:29

Right. But if you are melting from the ocean, you can have melt rates at the order of 100 meters a year underneath these ice shelves where the ice is coming afloat. So the problem is that this marine ice sheet instability that you were talking about, where you have this reverse sloping shelf of sea floor underneath, that is a geometric instability. As I said, it’s like a ball rolling down the hill. If you erode away something that’s stopping that ball, it will roll down the hill. And that’s the situation that we are in with things like Thwaites glacier. So even if we basically stopped emitting CO2 now, those glaciers that have had that buttressing force removed because the ice shelf has thinned and floating free, that will continue. You need to physically restrain that ice from flowing off the land. Now building a concrete wall, for example, that’s what originally what we thought we would need to do. But the it doesn’t make any sense. What you need to do is let the ice do its own thing. It knows where those buttress things used to be and it will find them if the ice shelf is thick enough. 

The way to get the ice shelf thick is to turn down that ocean melt rate from 100 meters a year to as close to zero as you can. And that’s what this concept of a curtain blocking access to the deep, warm waters is all about.

Paul Beckwith  40:29

So, this curtain would have to be clear, would have to be massive, right? Would it be anchored to the sea floor?

John Moore  40:35

Yeah, it’s anchored to the seafloor with concrete foundations. The length of the shortest length – that is the channel that is funneling water underneath the most vulnerable life shelf on the planet – is four and a half kilometers wide. I mean, four and a half kilometers, that’s a lunchtime stroll, really. The whole width of the Thwaites ice shelf is something like 100 kilometers, but that’s kind of irrelevant. The key thing is putting the plug in the bathtub. We’re not talking about how big the bathtub is, just where the water is flowing. And that’s four and a half kilometers across. 

Paul Beckwith  41:26

How high would it be? What’s the water depth?

John Moore  41:31

The water depth in those deep channels is up to about 1000 meters. the top of the curtain should be around 500 meters. So it needs to be something on the order of a few hundred meters, and on the order of 10 kilometers across. In reservoirs, people use surface floating curtains to separate warm waters on the order of a kilometer across and about 100 meters thick, deep.

Paul Beckwith  42:06

In the case of those reservoirs, that would be to reduce evaporation. And you’re talking about

John Moore  42:14

Oh, no. It’s to separate water of different temperatures. So it’s doing exactly the same kind of job. And the idea is to manage the temperature of the outflow of the reservoirs to better preserve fishing, salmon habitat.

42:30

Okay. So there are reservoirs where that technology is being used right at the moment?

John Moore  42:37

Well, those are crude approaches, okay. With the kind of materials that we’re talking about – we’re talking about high modulus polyethylene, for example. It’s the kind of technology that is employed in things like deep ocean drilling, or laying communications cables in the deep ocean, or even offshore wind turbines installations. So, if this was in temperate waters, we would have all of the engineering ability to start tomorrow. The difficulty is, of course, you’re in Antarctica. You’ve got the polar night, you’ve got these massive icebergs calving from Thwaites and Pine Island and places like that. Undoubtedly it would be the most challenging civil engineering project that humanity has ever done. But it’s not science fiction. We know how to do it. It just requires funding and political will.

Paul Beckwith  43:50

You also have the tidal changes and very rough wave action.

John Moore  43:58

Well, that’s the thing. Because the top of the curtain is about 500 meters deep, it’s well below tidal. We have thought about things like tsunamis: Would that make an impact? There’s a lot of unknowns; we need to do more. Looking at the interaction of the curtain with the aspiration flow up and over the curtain. There will be some flow like that. The most disastrous thing that we could think about was, if you get the thing flapping like a flag for some reason, then we can imagine it destroying itself. There is clearly a ton of engineering to go through. We’re not talking about being ready to install this tomorrow or next year. There’s at least a decade of engineering to go through. 

We would start in manageable places. You wouldn’t need even to have a glacier. You can do it where there are the kind of ocean currents where you could learn. You could start in a river. The Cambridge University engineering department actually are quite interested in doing a simple project in the Cam with this kind of curtain just to see how would it work in practice. You can learn a lot and scale, step by step, up the difficulty ladder, going through Greenland, and then finally towards Antarctica and Thwaites.

Paul Beckwith  45:44

Okay, now, you may have covered this already, but a couple more technical questions .The curtain would be anchored to the ocean floor, there’d be buoys on the top to lift it upwards, right? Would it let some water through or would it be completely opaque to water flow? Or would it block, say 80 percent? You know, a mesh sort of thing.

John Moore  46:15

This is a good question. We were talking about panels, because expect a 30 year lifespan for these kinds of plastic panels. They would be hinged at the foundation so they could rotate in different directions if the icebergs and things hit them. These panels would overlap. Where you would have two layers of panels, of course, in the aspiration over the top there will be some kind of an exchange flow. But the details of that can be controlled by engineering. You can have spoilers on the top of the curtains, for example, that determine how the separation goes over the top. As I say, there’s a ton of engineering that needs to be done. The concrete foundations can be installed by a variety of techniques, depending on the material, on the sea floor conditions. Our favorite design, the one that we’re able to cost most easily, is actually a longer curtain about 80 kilometers across, that’s out further away from the ice. It protects more glaciers and it’s in shallow water. And it’s in these eluvial sort of deposits, so the engineering is a lot easier. We’re firmer on the costs that would be required to do something like that.

Paul Beckwith  47:57

Now would you have some sort of power generator there to provide power to run sensors or actually run motors if you installed them to control the movement of the curtain? I guess you could use underwater turbines.

John Moore  48:21

We don’t want to have a lot of complicated things that can break down, so they’re basically passive. Obviously, we would instrument the shit out of them so we’d know what’s going on. And there is certainly power from these currents and available. We certainly will be using power but there are sources of power from the ocean there.

I’m not an engineer. Our stupid idea when we started this was, okay, let’s just block these passages with a pile of rocks. So we started talking to an engineer in in Vancouver, Barry Kiefer, he contacted us and says: “This idea is just plain stupid. Have you thought about these curtains? These curtains are a much more sensible way of doing it.” Of course, he’s absolutely right. He’s an engineer. There is other engineers and fluid mechanics people for example, in UBC in Vancouver, there are people in engineering and in glaciology. We have groups of people around the world – very small scale at the moment. Alfred Vader Institute, the engineering department in Cambridge University. One or two companies are starting to think this is an interesting idea, should we be investigating this? 

Metta Spencer  50:22

You make it sound as if maybe private industry could find a way to make a buck from it. I can’t imagine how that could be.

John Moore  50:31

Well, I think you’re absolutely right. And this is a key part of the greenlab work that we’re trying to do is, how do you monetize the AI sheets as a global good?  It is a global good in the same sense that old growth rainforests are, or the Amazon rainforest. It’s something that benefits everybody, but it only benefits that while it’s in existence. You might consider something like the payment for ecosystem services that the United Nations runs. Or the kind of funds that tell people not to cut down old growth forests. We also may consider the insurance industry, a levy on flood insurance globally. 

No one’s wanting or expecting guys in Kiribati or Bangladesh to pay for this thing. For sure, they would be the main beneficiaries but, obviously, the rich West causes most of this problem and, by right, a guy who buys a condo in Miami should be paying a hell of a lot more for this kind of thing than a guy in Bangladesh. 

As I said, we estimated if it’s 200 million people that would benefit, it’s of the order of $5 a year per person of those 200 million. But there’s no reason why it shouldn’t be limited to 200 million people because it’s a huge worry in Europe, you know: climate, refugees, climate migrants. It’s actually worthwhile for countries like Switzerland, for example, to pay for this kind of thing to avoid people from the developing world coming and wanting to settle in Europe. 

Peter Wadhams  52:28

It will be suddenly true that acceleration of loss of ice is one of the big problems facing the world because sea level rise is accelerating. And that’s coming from increased melt of ice sheets, especially in the Arctic, but also potentially in the Antarctic. So, if you can find a way to reduce the rate of loss, then that’s going to be really beneficial for the world in terms of reducing the rate of global sea level rise. 

John Moore  53:15

That’s what we hope. And that’s why for Greenland, it’s very important. Greenland wants to do something good. Is Greenland happy that the ice sheet goes away> In fact, they care about what happens to people in Bangladesh. I’m sure they do, like any rational human being does. It’s just that they never considered the ice sheet as being anything particularly worthwhile. They work on the sea ice, they benefit from the ocean resources. I’ve been telling them that the ice sheet is their ice treasure, this is what they’ve got. This is something that world cares about. They can gain enormous soft power and influence by being the good guys and conserving their ice sheets. So they can do that and benefit if we can control some of the outlets from Greenland. But also, they can be applying pressure to the Antarctic Treaty signatory people and saying, Hey, you guys, we’re doing our bit to conserve Greenland. We really need to do the same kind of thing in Antarctica. You guys need to step up and put your hand in your pocket.

Metta Spencer  54:38

Countries have some sort of pact to protect the Antarctic. Which countries are they and what’s the nature of the of the contract?

John Moore  54:52

The Antarctic is governed by something called the Antarctic Treaty System. There are 29 voting members of this system, which are actually the 29 richest countries on the planet, more or less. All of them except Switzerland have a coastline, so all of them will benefit by reducing sea level rise. The duty of the signatories to the Antarctic Treaty is to preserve the ice sheet as it is. And usually that’s taken as meaning you can’t drill for oil or mining minerals. That kind of thing. What we are arguing is that legally it means that you have to actively conserve that ice sheet because if people do nothing, even if people just turn off all of the CO2-burning motors in the world, the ice sheet will go away, because it’s this ball that’s rolling down the hill. In order to keep that ball, the ice sheet, you have to stop it. You have to provide the buttressing. You can’t just say, well, this is a bigger problem; it’s not just our 29 countries. No, this is something directly that the people governing Antarctica can do independently of all of those greenhouse mitigation measures.

Metta Spencer  56:36

What other things would be impacted by it? I don’t imagine there’s any shipping lanes around there. There probably are whales and fish. To what extent would other life forms be affected by the change in the currents of the ocean there?

John Moore  56:59

This is an excellent question. I’m glad you asked this. And it’s only recently that we’ve been talking to ecologists, and actually they have started to become interested in this idea. There will be some local impacts, both through the construction process, which won’t be 100%, clean, you know – it’s an engineering process. And as for changing the currents. I always say, Well, you have to compare risk for risk. The question is, what would happen if you didn’t do this? Not, what is the case now, but what will be the comparable situation? 

For sure, hundreds of kilometers retreat of the ice will change the marine ecology a hell of a lot more around Antarctica than just doing an intervention like this. At least that’s my feeling. I’m not an ecologist, I would love to have an ecologist say this, but that study needs to be done. 

The wider issue is: What happens to the waters that you stop going to the Thwaites? Are they just going to melt the next place here down the line, the next Domino, if you like? That’s why I was saying to Paul that, in fact, a lot of the Antarctic is stable in that it’s not vulnerable to this marine ice sheet instability. Those waters will melt the ice, but melt it in a more graceful way. You will get melt rates locally. The catastrophic thing with Thwaites is not the local melting, but the massive calving of the icebergs that are then carried away and then melting in the global ocean, not just locally. What you want is a managed situation, rather than this catastrophic collapse.

Metta Spencer  59:08

Okay, I am interested in putting people together who have some way of benefiting from collaboration. So I’m wondering: Are you looking for partnerships? Are you looking to form a connection with Peter and Paul, if their network can be of any value to you? Here’s my opportunity to invite you people to become friends.

Paul Beckwith  59:43

Yeah (smiles). Well, this is the first step. Right. One of my biggest concerns about Antarctic ice melting is, is actually Greenland melting. If there’s an overall rise of sea level, that’s going to push up the ice shelves in Antarctica. And the two poles are definitely connected. We see this in the Paleo records. But in Antarctica, the ice melt is solely from underneath, right? There’s very little ice melt on the surface, because, if we raise the temperature on Antarctica from minus 40 Celsius to minus 30 Celsius, nothing’s still going to melt on the surface, whereas Greenland is a different situation. We’re starting to get lots of air temperatures, well above zero over the surface of the ice, even three kilometers high at the surface of the ice over Greenland. So, we’re getting lots of melting on the surface. As we get more melting on the surface, the debris, the dust, etc, that’s in the ice becomes more concentrated at the surface and the albedo drops. It leads to even more and more melting on Greenland. It’s melting from above and below. So I would say it’s a lot harder to stop the Greenland situation than Antarctica.

John Moore  1:01:27

You’re absolutely right about that. At the moment, it’s about half and half from the air and from the ocean. We expect by the end of this century it will be something like 80%, from the air and 20% from the ocean. That is not an issue that you can solve with the seabed curtains. This is not a panacea for for everything. This is trying to put a band-aid on the worst thing. The sea level commitment from Greenland is likely to be a lot less than from Antarctica. Yeah, the pipe, the outlet glaciers in Greenland, are relatively confined in these quite narrow fields – a bit different from the situation in Antarctica, which is the wide base and much broader outlets. 

But yes, if you want to manage Greenland, yeah, maybe you want to be thinking about this. Geoengineering by other methods, whether aerosol injection or marine cloud brightening or something like that. The point that we are making with the Greenlanders is: You might want to do this for local benefits. For example, fishing is very important, and the fish species have changed radically over the last 30 years. And you may want to let the Greenlanders determine the ice and the fiord configuration that’s optimal for their way of life. There’s local benefits/

Peter Wadhams  1:03:42

I have to leave because I’ve got another meeting, which is a similar topic. It’s a cruise that we’re planning for going to Patagonia. It’s been a very interesting presentation. 

John Moore  1:04:09

Lovely to chat with you, Peter. It’s been it’s been a few years since we spoke. 

Paul Beckwith  1:04:16

It’s been fascinating to me also. I’ll be going to the COP climate conference in November in Egypt. It might be interesting to cover these ideas in one of the press release presentations there, so we should touch base about that possibility. John.

Metta Spencer  1:05:20

Thank you, John, for this presentation. You can count on hearing from somebody as a result because you’re going to stimulate some kind of conversation, I’m sure. Bye.