Sea Level Rise From Melting Ice Sheets Could Soon Be Locked In

Where today we talk broadly of climate change and it’s various effects, the conversation was once simpler. We called it “global warming” and fretted about cooking outside in the summer and the sea level rise that would claim so many of our favorite cities.

Scientists are now concerned that sea level rises could be locked in, as ice sheets and glaciers pass “tipping points” beyond which their loss cannot be stopped. Research is ongoing to determine how best we can avoid these points of no return.

Ice, Ice, Baby

The threat of sea level rise due to melting ice is often discounted by climate change sceptics. The common citation is that a floating ice cube doesn’t change the water level as it melts, due to the principle of displacement. However, this doesn’t account for the fact that much of the ice in the Antarctic actually sits atop land. When this ice melts, it directly leads to sea level rise of a potentially drastic scale.

While the loss of floating ice won’t directly cause sea level rise, worries are that the loss of the ice shelf will increase the melt rate of the Thwaites Glacier it’s holding back. Credit: NASA, public domain

Of prime concern is the Thwaites Glacier, which scientists have nicknamed the “Doomsday Glacier” for the perceived danger it poses. The glacier is held back, particularly in the east, by a large floating ice shelf. This slows the flow of the glacier and helps keep it stable. The floating ice shelf is further aided in this task as it sits against a large underwater mountain, acting as a brace.

Recently, scientists have noted that the floating ice shelf is showing worrying signs of deterioration. Large cracks have been spiderwebbing across the ice, prompting concerns for the long-term stability of the shelf. The effect is similar to cracks in a window; once they reach a certain point, the entire glass just shatters. Compounding the problem, the ice shelf appears to be losing its grip on the underwater mountain holding it in place as warmer waters melt the sheet from below.

When land ice sits on ground beneath sea level, it can let seawater in underneath if the ice sheet isn’t heavier than the denser seawater it would otherwise displace. This water then melts the ice from below at an increasing rate as the grounding line moves further inland. Credit: NASA, public domain

The Thwaites Glacier is already responsible for about 4% of global sea level rise each year. The concern is that with the loss of the floating ice shelf, the glacier could increase its flows towards the ocean, increasing up to 5% of sea level rise in the short term alone. Scientists currently expect the ice shelf to break up within the next 5 years or so.

The longer-term implications are profound, if uncertain at this stage. If the broader Thwaites Glacier breaks up and melts away, a process scientists expect could happen in as little as a few centuries, it would contribute a 65 centimeter rise to global sea levels. If the broader West Antarctic Ice Sheet were lost, it would add 3.3 meters to global sea levels, completely changing the world map.

We Prefer Greenland Icy, Not Green

Many glaciers, like the Jacobshavn Isbrae glacier, have been retreating since the Industrial era. The concern is that soon, their loss may be locked in regardless of future reductions in greenhouse gas emissions. Credit: NASA, public domain

It’s not just a problem in the Southern Hemisphere, either. Scientists believe that 1-2 meters of sea level rise may be locked in from glaciers in Greenland that seem set to melt regardless of what we do now. 140 years of records regarding ice-sheet height and the rates of glacial melting in the Jakobshavn basin indicate that there may be a feedback effect that causes rapid ice loss. As the ice sheet thins, it is more exposed to warmer air at lower altitudes, accelerating the effect.

The melting ice is also playing havoc with ocean circulation, too. The cooler waters from the melting Greenland ice are slowing currents responsible for transporting heat through the oceans around the world. Fears are that this could disrupt rainfall over crucial areas, create more droughts, and warm the southern oceans, further accelerating the melt of the West Antarctic Ice Sheet.

There is some solace to be had in the time scale of the melt predicted, for currently-living humans at least. It’s expected that the 1-2 meter rise from the Jakobshavn melt would take a few centuries to progress, even if we can’t stop it now. It’s also not certain that a tipping point has been passed, however, with global temperatures and greenhouse gas concentrations still rising, that point may be moot. Regardless, lacking a return to pre-industrial temperatures, researchers believe that significant ice loss, and corresponding sea level rise, is almost a certainty.

The most harrowing predictions suggest that the loss of Greenland’s ice sheets could be locked in at 1.5 °C of warming, which could be reached as soon as 2030. If the models are correct, once this point is reached, reducing emissions and stabilizing global temperatures would not be enough to rescue the ice sheet, which would continue to melt and raise sea levels slowly over a long period of time.

Future Outlook

Taken in isolation, neither glacier presents an immediate threat to our coastal cities in the next decade. However, if multiple climate systems continue being pushed beyond points of no return, as we’ve explored before, we may end up locking in significant negative changes before we’re capable of dropping emissions and stabilizing the climate.

[Banner image: “Surprise Glacier” by USGS. Thumbnail: Calving at Perito Moreno by NASA Goddard.]

124 thoughts on “Sea Level Rise From Melting Ice Sheets Could Soon Be Locked In

  1. Yeah, climate scientists are as full of it as people who say you need a ground wire on an outlet. Why? Didn’t need them for years and years! Then all of a sudden physics changes in the 60’s? Propaganda!

        1. I am seeing Tampa bay high tides getting higher over the last 60 years where I fished as a child. I understand that when the gov gets involved there may be a lot doubt but there seems to be a valid reason for people in flood zones to create a plan B over the next decade. In Miami, residents have developed the phrase (Sunny Day Flooding) as the high tides have been reaching million dollar homes & business in low areas.

      1. Intro to philosophy course as a gen-ed 20 years ago, but still remember the definition that was drilled into us:

        “An argument is a set of statements, one of which is a conclusion, the rest of which are premises, in which the premises are intended to support the conclusion.”

        1. No it isn’t!

          BTW You’ve stumbled into a python recitation. Just not the one of the most beat to death ones.

          When I was a kid we used to dream of philosophy courses. All we had were tattered copies of the cliff’s notes for DasKapital, some bricks and one Molotov.

    1. The use of these subjects as ideological discipline makes me suspect that we are incapable of doing anything about them. The war is not meant to be won; it is meant to be continuous.

    2. Your “great I was hoping for some unrelated climate propaganda” isn’t making any effort to have a discussion, while I am an opponent of censorship, your comment added no value, and your whining has no justification.

  2. There is a nearly free and effective solution. I was reminded just yesterday of the “ocean pastures” thing if I got that right. “Salting” the northern and southern oceans with iron minerals. Basically iron ore dust. It is so simple and cheap that there are those who think it is ignored because there is no money to be made (unless you sell seafood or want he salmon runs to return). I reacll this was discussed in the early 1980’s and tested on small scales a couple decades later before they were forced to halt. All signs pointed to fantastic.

    1. Not quite determined as effective:

      It can cause an algal bloom, but it would also add additional factors into a complex system that we do not fully understand.

      I put it in the same category as trying to use a nuke to disrupt/change the course of a hurricane. Might work. Might not. But we definitely do not understand the long term implications.

      1. It’s probably a lot safer to try in a controlled way than nuking a hurricane…

        Definitely a complicated problem that would require a lot of controls and study before being released into the wild.

        1. Might be complicated. Might be simple – like vitamin C to prevent scurvy. There were very promising results and no downside seen during, and after the experiment was stopped.

          1. I wouldnt call 2 positive experiments promising when one considers that another 11 experiments showed either ambiguous or no impact from the iron.

    2. well obviously the democrats would be for it, because socialism has worked before….somewhere….because we understand complex systems so well we can manage everything.

      get in the hole, and face the wall. you have been determined to be surplus population by the bureaucracy.

      1. Speaking of which >>100 million/yr since the early 60s; a > billion more every decade, along with an otherwise welcomed historical drop in the death rate. Irrefutably, the hottest fuel driving climate change. But just don’t expect the likes of Musk-Time mag’s Man of the Year-to offer anything but countless more climate changing rocket launches and even worse his self-serving warnings that > 8.8 billion simply aren’t enough. And this is the eco-idiot that so many here heap praises on?

  3. Of course sea level rise is ‘locked in’. It’s been rising at approximately 1.8mm per year for the last 100 years and will continue to rise at the same rate for the next 100 years.

    I call that ‘locked in’.

    1. “Dave_G says:
      June 23, 2022 at 11:58 am
      Of course sea level rise is ‘locked in’. It’s been rising at approximately 1.8mm per year for the last 100 years and will continue to rise at the same rate for the next 100 years.

      I call that ‘locked in’.”

      How many millimeters of soil and sand carried out to sea every year, do to natural erosion? Polar ice has been meting and reforming since, well forever. Just like every thing else, erosion happens natural, and eventually ends up in the oceans. Anybody else notice that 1.8 mm is a very tiny amount, compared to how big the oceans. About 80% of the planet surface is water. And it’s a huge planet. Computer models have a place, and a use. But, some use them as geeky video games, since fearmongering pays so well…

        1. That would be 30 miles down the road, and 1 or two valley’s over. I’m a couple hundred above my valley’s floor and looking at a mile wide canyon exit. Town will flood before my toes get wet

  4. What we have now is well-intentioned speculation. Science means you make a hypothesis and prove it by observation. There are too many unknowns here and the various models have had many alterations. Making almost any prediction at this point is sure to be disproved by measurement later. However, given that the future of the planet hangs in the balance you may want to err on the side of caution. I spent decades working on weather satellites. Many billions spent. I do not perceive an increase in accuracy of forecasting in proportion to the dollars and hours spent. Sure, lots of data. Good. Translation to better models? Not so much. Yes, climate and weather are not the same. But, when anybody starts making specific predictions I look out the window to see if it’s raining. The damage we’re doing is undeniable. How much? When? The models are not fact. The prudent approach is to stop inflicting damage. Simple answer. Will things get better or worse as a result? Don’t know yet.

    1. It is inherently unpredictable because humans. The behavior of people can not be predicted in the modeling and simulations. Thus the dire warnings are foolhardy and they fit the Farnsworth criteria of valuable research by needing decades of work with hundreds of grad students and machines powered by truckloads of burning grant money. And thus the desire to control and contain everyone in nice tidy Thunberg Housing Units filled with frowning angry Thunbergian youth.

    2. “women’s studies majors”

      Your comments are the internet version of spitting on people. Could you share with us why you feel so entitled to write about people that way?

  5. worst case scenario, all the rich people with ocean front property will have to move. let me play the littlest violin for them. lets also hope that nobody was dumb enough to build a nuclear power plant that low.

  6. I’m in favour of censorship as posting unnecessary negative or trolly comments causes more global warming and rising sea levels. Think before you type. Every key stroke burns more fossil fuels.

    1. Everyone thinks their entitled to “free speech” on someone else’s paid bandwidth … HAD has zero obligation to post any specific comment and has near full freedom to choose what they publish. To the haters, find another site to moan on.

    2. Technically the act of censoring is adding more energy into the equation as an extra process. Also promoting continued discussion on the matter. If we really want to help we should just not comment, or visit the site, or exist in general.

    3. id rather the trolls make their trolling visible so we know who the trolls are. last thing you want are trolls in stealth mode. that kind of trolling tends to be a lot more destructive.

  7. Hackaday’s comment section is a *much* more pleasant place today than it used to be. Someone who may just be starting out spends a ton of time on building something super cool, and the first comment is about how that person wasted their time, they obviously don’t know what they are doing, any idiot could do better, etc. If Hackday is using comment moderation to remove these nasty non-constructive comments, then good job Hackaday! You did it, the comment section isn’t a shark tank anymore. If this happened organically, then good job humans! You did it, you learned that building yourself up doesn’t require tearing someone else down.

      1. Our writers write up projects they like, and only projects they like, which might explain your perception that we’re overly positive. It’s nothing but selection bias, 24/7. :)

        But conflating “enthusiasm” with “general toxic hype” is too cynical, IMO.

  8. That’s a new one. The Earth is not falling into the Sun, the reason for the “temperature phenomenon” has been known for over a hundred years. You’ll find it mentioned in the scientific literature.

        1. Our planet us quite literally ‘falling into the sun’. So, let me explain.

          Our planet is in orbit around the sun.
          That orbit consists of two forces, the gravitational pull of the sun and inertia, the force pulling our planet foreword in a straight line. The two forces counteract each other resulting in our planet rotating around the sun.

          You could look at any rotation around a body – the moon around the earth, our track around the sun – as the rotating object continuously falling towards the rotated object but we don’t because the rotating object’s inertial drives the rotating object foreword. The forces counteract to plot a curve and not a straight line right into the center of the sun or straight line into space.

  9. That’s why they call it ‘climate change’ today. If it gets warmer, covered. If if gets colder, covered. Meanwhile tin foil hats say the sky is falling and bleed more money from all of us. Quite a racket they got going and plenty of ‘believers’ to help ’em :) .

    1. Rclark you don’t get it, al gore said we were going to freeze to death by 20xx and national geographic said we were going to freeze then bake by 20xx too, why would these publications print sensationalist articles about the latest fad to sell more and lie to me, why can’t they look at the science

  10. The cause is obvious and the solution is simple.

    The cause: There are far too many of us Humans on the Planet Earth.

    The solution: Invent a machine that painlessly makes humans that step into it disappear, like the one on a certain Star Trek program. And because I believe that he who cares most should pay most, I believe those most passionate about Global Warming should step in first.

    1. To avoid adding more carbon from cremation, they could get themselves rammed down old oil field bore holes. Enough pressure can make them fit the pipe. Better yet is be speared into the mud at the plate subsidence zones. For example they could be shot into the clay off Washington and Oregon and some many millions of years later they will be blasted out of the Cascade volcanoes. What could be more fitting?

      1. But their carbon wouldn’t be added, it would just be recycled…

        And anyways, I believe that Global Warming exists and I believe that we did this to ourselves. I just don’t believe we can stop it, and some of these extremists don’t understand that what they propose (or insists) is just as dumb as mine or your comments!

        I guess it’s easy to theoretically save the world from Global Warming from your resource consuming smart phone while in your indirectly coal fired air conditioned house.

      2. I told my family to just by a shovel and dig a whole and drop me in it. Just a piece of raw meat at that point anyway. My brother was spreading my dad’s ashes and wind blew some of it into his mouth. My brother litterally has some of dad in him.

  11. Not a hack, and probably not even a fact. Show me the signal in the Keeling Curve dataset that matches the economic slowdown due to covid and I may believe you know enough to even link human activity to the rate of global CO2 rise. I’m serious, I keep asking for that basic science and nobody can give it to me. As for ice melt rates, meh it is more dependant on the direction of sea currents than anything else and that is chaotic, so don’t kid yourself that you can predict it, there is nothing in the human mathematical toolkit that allows you to do so. Feel free to show me your math though… after you have solved something simpler like the three body problem…

  12. Climate Models Of Incompetence
    By Dr. Duane Theresher – 6 Feb 2019


    NCAR is a premier climate modeling institution in the world with one of the most famous climate models, which at the time was called the Community Climate Model (CCM).

    My code is still in CCM (or whatever warm fuzzy new name they yet again gave it). It even has my name on it; look at the code here and search for Thresher (and note that they even misspelled my first name once).

    Climate scientists are not programmers. I’m unique in that respect. Climate scientists also don’t want to do the hard work — taking courses and getting degrees — to become programmers. UA/NCAR was my epiphany that climate scientists’ IT incompetence was destroying climate science.

    After my M.S. from UA/NCAR, I fled to Columbia University and NASA GISS (Goddard Institute for Space Studies), in New York City, for a Ph.D.

    I thought that going to a famous private university like Columbia and a famous organization like NASA would improve the climate modeling situation. I could not have been more wrong; it made it worse, much worse.

    1. I had some exposure to the Atmospheric Physics community, real hard science guys and they were routinely horrified by the lack of rigor in the climatology field. One time we pulled a paper, calculated the measurement errors using standard techniques, and discovered we could draw a line angled just as sharply downwards, or even a sine wave of amplitude 3 degrees C, period of 2 to 20 years, and it would fit inside the error bars. Quite an astounding mess.

      1. In case you assume my standpoint from that. I am open minded but want to see the best, most accurate characterisation of the situation, not some “more or less” flummery that has us doing irresponsible things like blaming foxes when it was stray dogs killing the sheep, or having an uncalibrated response on the level of pissing off a bull elephant with a peashooter, or using a nuke to take out an ant.

    1. Competent computer modeler: Someone who can get the model to tell him anything he wants.

      I know, I’m a ‘competent computer modeler’.

      This was not an original thought in 2014. Rather something understood by _everybody_ doing it for a living.

  13. Yet another article predicting global doom in 5 to 10 years. Funny thing is that I’ve been reading these 5 year predictions for the past 30 years. Remember Al Gore anyone?

  14. Hello, here the bird of misfortune. Today I put you in the confidence…
    We find in this article the same figures as in the last IPCC report (2021). That is a rise in sea level of about 1-2 meters within a few centuries. A better understanding of the ice dynamics in Greenland and Antarctica now makes it possible to quantify data which until now have been purely qualitative. These data are now part of the new models. And that gives… 16 meters. This is what you will be able to read in the next IPCC report.

  15. If we were actually moving *CLOSER* to the Sun, the effect would be a small acceleration that is almost a linear velocity even over the century. Unfortunately for your argument tidal forces have the Earth moving slowly further from the Sun at this time.

    Once we spin down maybe we’ll fall back in but that’s a long ways off. (I didn’t do the calculation for that, just a guess)

  16. I come here for hacks. this is not a hack.

    I didn’t realize you were the not-hack police. you do understand that the bandwidth is reliant on people who come here, right? people who come here for hacks?

    post not-hacks in not-hack spaces. post hacks here.

    why is that so hard to understand?

    oh yes, now I get it this a religion, and you must have people affirm your beliefs. well no, that’s not what this is for.

    1. I didn’t realize you were the is a hack police. Don’t like what you see, then you are welcome to the door. Why is that so hard to understand? Ironic you don’t see everything you are arguing applies to you, but you seen to see yourself as an exception that rules don’t apply to (we call that entitlement here).

  17. Some of these comments, yikes. Antarctica and Greenland are both shedding off well over 100-200 billion tonnes of ice every year, and the same goes for sum total of all of the other glaciers in the world. It’s not that complicated. There is a satellite in space and it measures a laser’s 2 way travel time, that gives you volume change. We’ve got a pretty good idea about how dense snow and ice are and that gives you mass change. It all goes somewhere and the oceans rise. Get a grip people, it’s time to face reality.

    1. Here’s a reality: the world sucked because of people. Let the planet do what it needs to get rid of us. The planet will be a whole lot better without us to keep it sucking.

      Melt away, I say.

      1. I really don’t understand this infantile nihilism.
        Yes, there is a lot of fannying-about on the planet – but we have art, literature & architecture; empathy, love & compassion here. This speck of dirt we all live on could well be the single solitary place where conscious life managed to drag itself up out of the mud – & you’re happy to nonchalantly extinguish it?
        The human race certainly needs to grow up & take a long hard look at itself in the mirror – but Picard’s dream could still some day become reality…

  18. Does anyone really think even long term global warming can hold off the next ice age for any amount of time to really matter?

    Rising sea levels because of “fresh” water are just what the Dead Sea needs to be reconnected to the sea and restored. Yes! And how many more species will thrive in the sea once the salt percentages come down?

    Let’s not forget about all that “new” land people will be able to own and build on once we get rid of that nasty ice covering it’s surface.

    Floating through the former streets of New York among the sky scrapers on boats like they do in Venice sounds wonderful to me! I’ve never had any desire to visit that city but the underwater version sounds fun. The muggers will have to adapt as purse nabbing and running down a street will be impossible.

    1. Yes. To my mind, engineers (particularly hardware / software engineers) should understand the science well enough.

      But IMO there are aspects of engineering as a culture and profession that lends itself to denialism/skepticism. Probably the biggest influence as I see it is that engineers tend to be conservative. Most engineers are trained to use already established methods, algorithms, and processes rather than trying to work everything out from scratch. As a consequence, they tend to base their work on authorities rather than science per-se (this is why most engineers favour hydrogen fuel cell cars, rather than EVs, HFCs (or H2 combustion engineers) use technology that’s conceptually more familiar).

      Secondly, engineers tend to be cynical about people’s motives. For example, they tend to doubt the motives of climate scientists, because they doubt everyone’s motives. The big difference though is that they work day in and out with an established body of fossil-fuel era knowledge and tools; of which a significant (perhaps majority) has to be replaced if climate scientists are right. I think this represents a threat to their sense of expertise, but it won’t be seen by most engineers from that angle. Instead what they see is “stuff that works” vs an alternative and less well established set of practices that could be snake oil for all they know.

      So, those two sides tend to play out a lot in endless repetitions of conventionalism and cynicism. However, things do change as new bodies of expertise make their way into the mainstream, or at least leading edge.

        1. Very insightful. It’s appalling the lack of progress made in biofuels (Shut up Dude this isn’t about ethanol mixed with gas or the extremely low efficiency way done only for government back hander subsidies that it is in the US. Probably a planned failure.)

  19. What if Greenland and Antarctica become habitable? What resources might be under the ice? Hasn’t the cycle of the earth always ben changing on a 100, 500, 1000, 10000, etc. year cycle. The sun has a known 11 year sunspot cycle. What cycles exist in the solar system.? Unfortunately science is often pollical science.

    1. Yes, all the people in low-lying countries who are displaced, can move to Greenland.
      May as well do it while we are relatively prosperous and can afford the relocation costs.
      Greenland area can easily accommodate Bangladesh, Netherlands and east of UK.

  20. What we ought to be working on is a national system of water pipelines, to move flood waters to drought-stricken areas.

    But that requires a national will and a common desire to tackle big problems, which the USA hasn’t mustered since the ’60s.

    But hey… how half the country can use women as baby farms!

    1. Yes that’s one way of looking at it: Don’t deny that CO2 in the atmosphere causes warming, just embrace it instead.

      So now you can be either a “status quo” person trying to resist change, or a “gung ho” person going for it, whatever the consequences. (And, I expect, some spectrum in between the two extremes).

      There are pro’s and con’s to each approach.

      We could have fun modelling the end game of gung ho, versus status quo. Well, we know what status quo is, it’s comfortable for maybe 80% of the population. Will gung ho be that much worse?

  21. “Doomsday” implies a sudden catastrophic event. Everything changing in a single day.

    Sea level rise will happen slowly over decades.

    There is plenty of time for us to adapt. There will be no day of doom.

    The only thing truly at risk from sea level rise are established economic interests, and maybe some cultural artifacts and sites. Everybody can be just fine.

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