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The Hidden Risk Behind Melting Glaciers · How To Protect The Ocean

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  Antarctica's glaciers are collapsing from below and faster than we thought.
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  We've been looking at Antarctica the wrong way.
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  The biggest threat to its glaciers isn't coming from the
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  air in the warm atmosphere.
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  It's coming from the Ocean beneath them, and it's accelerating.
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  This is the How to Protect the Ocean Podcast, your weekday Ocean news update.
• 0:21
  If you care about staying informed on the Ocean every weekday, hit that
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  follow button right now so you don't miss tomorrow's interview where we
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  talk to people from Ocean Networks Canada engineers who have gone down to
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  Antarctica to install data acquisition systems, and they talk about what
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  it's like to work in Antarctica.
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  So if you wanna know what it's like to be a field biologist or a field
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  mechanic or engineer in Antarctica, then you don't wanna miss tomorrow's story.
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  Antarctic glaciers flow from the land into the Ocean.
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  At the edge they form ice shelves.
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  Floating extensions of ice.
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  Now these shelves are very important.
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  They act like buttresses.
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  They slow down inland ice flow, and they stabilize the entire system.
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  And if you know how important stability is, you would've listened to my episode
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  from yesterday that we talked about emperor penguins and their reproductive
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  stability that they require, right?
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  The stability they require for the reproductive cycle.
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  Now, if the shelves weaken, glaciers accelerate.
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  So think about a dam.
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  You have this structure that is holding water back.
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  Now, if there is a hole in this structure, water starts
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  spurting out in different things.
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  If you watch any kind of cartoon where you see a dam kind of burst, you start to see
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  the water kind of spurred out and there's like an animal that comes in either
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  foghorn langhorn or somebody tries to
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  plug it with their finger and then another hole comes up, they chew it all
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  in and they got their feet involved.
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  And it's kind of funny.
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  That's a funny part because it's a cartoon.
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  It's not real.
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  But when a dam bursts, all the water flows out and it's the same
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  thing with the edge of the ice.
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  If that ice shelf kind of bursts all the broken up ice just kind
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  of flows out and into the Ocean.
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  It can be a very scary thing to see.
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  It's kind of interesting to see, but it's something that's very weird and not
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  normal to see, although we're kind of normalizing it now with climate change.
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  Now, the key driver here of warm deep water is the circumpolar deep water.
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  The CDW is what we're gonna call it from now on.
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  This relatively warm water moves onto the continental shelf, flows under ice
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  shelves, and melts them from below.
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  Now this process is called basal melting.
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  And basal melting is essentially, it's warm, but it's still near freezing.
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  It's warmer than the surrounding waters, but it's still pretty cold.
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  Any kind of small temperature difference when you're looking at ice.
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  If you put ice in a cup underneath a faucet and you start to increase
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  the temperature just a little, little bit, you'll start to
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  see that ice melting pretty fast
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  'cause it's used to cold, cold areas.
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  And once you see a small temperature change, you see that
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  change in that piece of ice.
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  So recent field studies are using autonomous underwater vehicles, AUVs.
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  They're using moorings, they use satellite imagery, and they have revealed
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  that melt rates are highly uneven.
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  It's not that it's just constantly going up.
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  Warm water pulses can rapidly increase melting.
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  So as we see this not being uniform.
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  Right melting.
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  It's starting to just kinda like come in in different pulses where warm
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  water gets shut up every once in a while and they increase the melting.
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  And some areas are far more vulnerable than expected,
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  so it's not uniform melting.
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  It's targeted weakening of these sort of edges.
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  And that's where we're gonna see problems.
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  It's hard to study ice 'cause it looks like it's one thing, but there's different
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  parts of the ice that make it interesting.
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  I am not an expert in that, but imagine like thinking about like
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  area that is eroding on the inside.
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  Things are starting to melt so that ice is starting to break up.
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  But once the edge goes, that's when you really see it.
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  That edge doesn't go, then you won't really see it right away
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  'cause it's kind of keeping it intact.
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  But once you get that one break, everything goes.
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  So the way these glaciers, the glacier is a major focus because it's grounded
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  below sea level and it's vulnerable to Marine ice sheet instability.
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  Okay.
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  So it's very important.
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  Now, recent findings of this glacier shows that ice shelf
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  fractures are actually expanding.
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  And the grounding line retreat is accelerating and collapse could trigger
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  wider west Antarctic instability.
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  That's a big change.
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  We don't wanna see that.
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  Now when we look at Marine ice sheet instability, it's one
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  of the most important concepts.
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  If a glacier sits on a slope that deepens inland, then as it retreats,
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  it becomes more unstable and retreat accelerates automatically.
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  This creates a self-reinforcing collapsed process.
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  And I know that's complicated 'cause it took me a while to kind of figure it out.
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  But essentially what's happening is, as everything is starting to
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  melt slowly and non uniformly, it's starting to break it all up.
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  And as we start to see retreat, it just becomes more and more
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  unstable 'cause the inner parts are getting more and more unstable.
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  Now some of the models that were run back in the day, they didn't
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  fully capture Ocean heat transport.
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  And so , they underestimated the risk and because they simplified ice self
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  structure and they underestimated the fracture dynamics of these glaciers.
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  And so new models are showing faster timelines and higher
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  C level contributions.
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  Now climate models are really interesting 'cause a lot of people are like, oh,
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  models are so bad for like, it's a frustrating topic to talk about because
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  models are models and they're as good as the data that goes into them.
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  And as we learn more and more about these models and we learn more and more
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  about climate change and geophysical dynamics of the planet and ice movement
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  and ice sheet dynamics and so forth and melting and all these different terms
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  that, frankly, sometimes I don't even understand.
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  The models become more accurate as we start to move forward.
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  They evolve and they get better and better.
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  So we make less assumptions because we may have more data or we may
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  understand a specific process that allows us to pinpoint certain aspects.
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  But the fact is that these climate models are starting to target
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  more things and they're starting to predict that we underestimated
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  the results that we predicted before and now it's getting faster.
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  So instead of getting melting slower, we're actually seeing faster melting.
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  Science changes that way.
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  It's never perfect.
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  And a lot of people are like, well, that perfection can really overestimate things.
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  And at times, yes, it can overestimate things.
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  That's why it's science.
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  There's no emotional involvement in science.
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  It's math.
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  And the math either tells you, you are doing correct, you're
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  accurate or you're not accurate.
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  And sometimes the methods are not great and we start to learn certain things
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  and we start to get better at them.
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  But it very rarely shows that we're actually overestimating
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  things when we use models.
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  We actually are underestimating things a lot of the times, especially
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  when it comes to climate change.
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  And that can be a dangerous thing to think about.
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  So if we don't adhere to the original models and we don't throw caution
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  in the wind like we didn't do before, we're in trouble and this is what
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  happens when we ignore the science.
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  And so like, when we look at sea level rise
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  and what it really means when we start to see ice melt and
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  the sea level getting increase.
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  If major Antarctic glaciers destabilize, sea level rise accelerates globally.
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  Think about that.
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  If the glaciers starts to destabilize, which they are destabilizing, sea
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  level rise will accelerate globally.
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  We'll start to see those changes.
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  Even a partial collapse could mean tens of centimeters to meters over time.
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  It doesn't sound like a lot, but when you have some low lying areas, including
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  the US in certain parts of the US and Canada and other places, tens of
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  centimeters to meters actually makes a huge difference because our sea level,
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  where we are with land sometimes is not
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  above sea level.
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  Usually it's below sea level.
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  And so certain areas are gonna be more vulnerable than others.
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  And those are just, just above sea level, which won't be in the future Florida.
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  And so that will be interesting.
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  Now, of course, this affects coastal cities, infrastructure and entire nations,
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  especially when we look at like these smaller islands that are sitting docks
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  and they're trying to just live the life that they live and they have to
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  be in an area where they're vulnerable.
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  Turks and Caicos is gonna be vulnerable.
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  Certain parts of the Bahamas are gonna be vulnerable.
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  There's islands in the Southeast Pacific that have already had
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  to move, like smaller islands that we may not even know of.
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  But I know populations have had to move.
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  Indigenous populations have had to move after being there for
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  centuries, maybe longer, millennia.
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  It's a difficult thing to watch from a human perspective because
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  this is like culture and history and lives are being affected.
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  Melting Antarctic ice can also affect the Ocean salinity because
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  you're getting a fresher water in the system and a lot more fresher water.
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  And then, of course, Ocean circulation patterns, global
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  ocean circulation patterns.
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  The amoc system.
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  As we get more fresh water on the top, it caps the warmer
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  salt water from evaporating.
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  It's gonna be a mess.
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  And of course, you have fresh water input that can disrupt deep water formation
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  and then alter climate systems as well.
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  Are we near a tipping point?
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  Scientists are asking like, are there some glaciers already
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  past the point of no return?
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  We don't fully know, but the signs of instability are increasing.
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  And that's something that will put us more towards a tipping point.
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  This is not just over-hyping the situation.
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  This is telling you that worldwide scientists have been seeing this for a
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  while and it's getting worse and worse.
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  And so when I say we have to act, we have to act.
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  This is not where we can elect anybody.
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  Who's just coming up?
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  That's a reality star and just doesn't understand science and doesn't understand
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  the world, but understands money.
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  It's not just about the economy, it's about our planet.
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  And it's about when we start talking about the polls, you have to be in
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  a negative situation because you're like a negative messaging because the
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  polls are important to us and we're treating 'em like crap, to be honest.
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  Antarctica is not just melting, it's actually destabilizing from below.
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  And once that process starts, it's very difficult to stop.
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  And so when we talk about tipping points, we may already be there.
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  I have no idea.
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  It's something that's really hard to do.
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  But it's not all bad.
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  We are seeing people getting, gathering more data.
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  We are seeing people working and doing the good fight to work in the
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  courts to stop governments from doing what they're doing to harm the Ocean
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  worse or harm the planet even worse.
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  We are seeing people who are acting, whether in businesses and nonprofits
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  and academic institutions and government and the people who work in government,
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  the civilians, not the politicians.
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  They're actually working to help the Ocean.
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  And I think that's really important.
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  So if you want to hear good news and there will be more good news
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  later on, I promise, I swear to God, follow the podcast for more
• 10:18
  Ocean science and conservation that connects you directly to your world.
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  That's what we're here to do here at the How to Protect the Ocean Podcast.
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  I'm your host Andrew Lewin.
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  thank you so much for listening.
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  I hope you tune in tomorrow to hear from Ocean Networks Canada engineers and what
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  that was like to work in Antarctica.
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  Thank you so much for joining me on today's episode of the How
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  to Protect the Ocean Podcast.
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  Have a great day.
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  We'll talk to you tomorrow and happy conservation.