The Hidden Risk Behind Melting Glaciers

0:00 Antarctica's glaciers are collapsing from below and faster than we thought. We've been looking at Antarctica the wrong way. The biggest threat to its glaciers isn't coming from the air in the warm atmosphere. It's coming from the Ocean beneath them, and it's accelerating. This is the How to Protect the Ocean Podcast, your weekday Ocean news update. If you care about staying informed on the Ocean every weekday, hit that follow button right now so you don't miss tomorrow's interview where we talk to people from Ocean Networks Canada engineers who have gone down to Antarctica to install data acquisition systems, and they talk about what it's like to work in Antarctica. So if you wanna know what it's like to be a field biologist or a field mechanic or engineer in Antarctica, then you don't wanna miss tomorrow's story.

0:46 Antarctic glaciers flow from the land into the Ocean. At the edge they form ice shelves. Floating extensions of ice. Now these shelves are very important. They act like buttresses. They slow down inland ice flow, and they stabilize the entire system. And if you know how important stability is, you would've listened to my episode from yesterday that we talked about emperor penguins and their reproductive stability that they require, right? The stability they require for the reproductive cycle. Now, if the shelves weaken, glaciers accelerate. So think about a dam. You have this structure that is holding water back. Now, if there is a hole in this structure, water starts spurting out in different things.

1:29 If you watch any kind of cartoon where you see a dam kind of burst, you start to see the water kind of spurred out and there's like an animal that comes in either foghorn langhorn or somebody tries to plug it with their finger and then another hole comes up, they chew it all in and they got their feet involved. And it's kind of funny. That's a funny part because it's a cartoon. It's not real. But when a dam bursts, all the water flows out and it's the same thing with the edge of the ice. If that ice shelf kind of bursts all the broken up ice just kind of flows out and into the Ocean. It can be a very scary thing to see. It's kind of interesting to see, but it's something that's very weird and not normal to see, although we're kind of normalizing it now with climate change. Now, the key driver here of warm deep water is the circumpolar deep water.

2:12 The CDW is what we're gonna call it from now on. This relatively warm water moves onto the continental shelf, flows under ice shelves, and melts them from below. Now this process is called basal melting. And basal melting is essentially, it's warm, but it's still near freezing. It's warmer than the surrounding waters, but it's still pretty cold. Any kind of small temperature difference when you're looking at ice. If you put ice in a cup underneath a faucet and you start to increase the temperature just a little, little bit, you'll start to see that ice melting pretty fast 'cause it's used to cold, cold areas. And once you see a small temperature change, you see that change in that piece of ice.

2:55 So recent field studies are using autonomous underwater vehicles, AUVs. They're using moorings, they use satellite imagery, and they have revealed that melt rates are highly uneven. It's not that it's just constantly going up. Warm water pulses can rapidly increase melting. So as we see this not being uniform. Right melting. It's starting to just kinda like come in in different pulses where warm water gets shut up every once in a while and they increase the melting. And some areas are far more vulnerable than expected, so it's not uniform melting. It's targeted weakening of these sort of edges. And that's where we're gonna see problems. It's hard to study ice 'cause it looks like it's one thing, but there's different parts of the ice that make it interesting.

3:37 I am not an expert in that, but imagine like thinking about like area that is eroding on the inside. Things are starting to melt so that ice is starting to break up. But once the edge goes, that's when you really see it. That edge doesn't go, then you won't really see it right away 'cause it's kind of keeping it intact. But once you get that one break, everything goes. So the way these glaciers, the glacier is a major focus because it's grounded below sea level and it's vulnerable to Marine ice sheet instability. Okay. So it's very important. Now, recent findings of this glacier shows that ice shelf fractures are actually expanding. And the grounding line retreat is accelerating and collapse could trigger wider west Antarctic instability.

4:19 That's a big change. We don't wanna see that. Now when we look at Marine ice sheet instability, it's one of the most important concepts. If a glacier sits on a slope that deepens inland, then as it retreats, it becomes more unstable and retreat accelerates automatically. This creates a self-reinforcing collapsed process. And I know that's complicated 'cause it took me a while to kind of figure it out. But essentially what's happening is, as everything is starting to melt slowly and non uniformly, it's starting to break it all up. And as we start to see retreat, it just becomes more and more unstable 'cause the inner parts are getting more and more unstable. Now some of the models that were run back in the day, they didn't fully capture Ocean heat transport.

5:03 And so , they underestimated the risk and because they simplified ice self structure and they underestimated the fracture dynamics of these glaciers. And so new models are showing faster timelines and higher C level contributions. Now climate models are really interesting 'cause a lot of people are like, oh, models are so bad for like, it's a frustrating topic to talk about because models are models and they're as good as the data that goes into them. And as we learn more and more about these models and we learn more and more about climate change and geophysical dynamics of the planet and ice movement and ice sheet dynamics and so forth and melting and all these different terms that, frankly, sometimes I don't even understand.

5:44 The models become more accurate as we start to move forward. They evolve and they get better and better. So we make less assumptions because we may have more data or we may understand a specific process that allows us to pinpoint certain aspects. But the fact is that these climate models are starting to target more things and they're starting to predict that we underestimated the results that we predicted before and now it's getting faster. So instead of getting melting slower, we're actually seeing faster melting. Science changes that way. It's never perfect. And a lot of people are like, well, that perfection can really overestimate things. And at times, yes, it can overestimate things. That's why it's science. There's no emotional involvement in science. It's math. And the math either tells you, you are doing correct, you're accurate or you're not accurate.

6:27 And sometimes the methods are not great and we start to learn certain things and we start to get better at them. But it very rarely shows that we're actually overestimating things when we use models. We actually are underestimating things a lot of the times, especially when it comes to climate change. And that can be a dangerous thing to think about. So if we don't adhere to the original models and we don't throw caution in the wind like we didn't do before, we're in trouble and this is what happens when we ignore the science. And so like, when we look at sea level rise and what it really means when we start to see ice melt and the sea level getting increase. If major Antarctic glaciers destabilize, sea level rise accelerates globally. Think about that. If the glaciers starts to destabilize, which they are destabilizing, sea level rise will accelerate globally.

7:12 We'll start to see those changes. Even a partial collapse could mean tens of centimeters to meters over time. It doesn't sound like a lot, but when you have some low lying areas, including the US in certain parts of the US and Canada and other places, tens of centimeters to meters actually makes a huge difference because our sea level, where we are with land sometimes is not above sea level. Usually it's below sea level. And so certain areas are gonna be more vulnerable than others. And those are just, just above sea level, which won't be in the future Florida. And so that will be interesting. Now, of course, this affects coastal cities, infrastructure and entire nations, especially when we look at like these smaller islands that are sitting docks and they're trying to just live the life that they live and they have to be in an area where they're vulnerable.

7:58 Turks and Caicos is gonna be vulnerable. Certain parts of the Bahamas are gonna be vulnerable. There's islands in the Southeast Pacific that have already had to move, like smaller islands that we may not even know of. But I know populations have had to move. Indigenous populations have had to move after being there for centuries, maybe longer, millennia. It's a difficult thing to watch from a human perspective because this is like culture and history and lives are being affected. Melting Antarctic ice can also affect the Ocean salinity because you're getting a fresher water in the system and a lot more fresher water. And then, of course, Ocean circulation patterns, global ocean circulation patterns. The amoc system. As we get more fresh water on the top, it caps the warmer salt water from evaporating.

8:39 It's gonna be a mess. And of course, you have fresh water input that can disrupt deep water formation and then alter climate systems as well. Are we near a tipping point? Scientists are asking like, are there some glaciers already past the point of no return? We don't fully know, but the signs of instability are increasing. And that's something that will put us more towards a tipping point. This is not just over-hyping the situation. This is telling you that worldwide scientists have been seeing this for a while and it's getting worse and worse. And so when I say we have to act, we have to act. This is not where we can elect anybody. Who's just coming up? That's a reality star and just doesn't understand science and doesn't understand the world, but understands money. It's not just about the economy, it's about our planet.

9:21 And it's about when we start talking about the polls, you have to be in a negative situation because you're like a negative messaging because the polls are important to us and we're treating 'em like crap, to be honest. Antarctica is not just melting, it's actually destabilizing from below. And once that process starts, it's very difficult to stop. And so when we talk about tipping points, we may already be there. I have no idea. It's something that's really hard to do. But it's not all bad. We are seeing people getting, gathering more data. We are seeing people working and doing the good fight to work in the courts to stop governments from doing what they're doing to harm the Ocean worse or harm the planet even worse. We are seeing people who are acting, whether in businesses and nonprofits and academic institutions and government and the people who work in government, the civilians, not the politicians.

10:07 They're actually working to help the Ocean. And I think that's really important. So if you want to hear good news and there will be more good news later on, I promise, I swear to God, follow the podcast for more Ocean science and conservation that connects you directly to your world. That's what we're here to do here at the How to Protect the Ocean Podcast. I'm your host Andrew Lewin. thank you so much for listening. I hope you tune in tomorrow to hear from Ocean Networks Canada engineers and what that was like to work in Antarctica. Thank you so much for joining me on today's episode of the How to Protect the Ocean Podcast. Have a great day. We'll talk to you tomorrow and happy conservation.