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    Default How much would the sea level rise if the ice caps totally melted?

    Googling the question gives me three conflicting figures - 195 feet (NASA), 216 feet (National Geographic), or 230 feet (US Geological Survey).

    My family's house is 223 feet above sea level, I'm trying to figure out if a worst case scenario means that we're screwed or if it means that we're rich
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Some of the difference might be how much thermal expansion of the ocean you figure in.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    I'd wager more of the uncertainty is that getting exact figures for how much water is tied up in ice caps is tricky, so there's some estimation at play. Of the three I'm inclined to think that the US geological survey would be the best guess, but it is all guesswork.

    However, even if the Nasa figure is right and your property is a leisurely stroll from the beach, I don't think that'll significantly change just how screwed you are from the whole rest of the situation.

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Also estimating the shape of the coast everywhere in the world.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Does anyone actually believe that all the ice caps on the entire planet will actually melt entirely?

    Why not ask "how dark will the sky be if every volcano on the earth erupted?". Or "how hot would it be if the sun expanded by 50%?". Or "how big would the traffic jam be if every car broke down at the same time?". Kinda silly. Doubly so to be worried about where your house may be (presumably in your own lifetime) relative to the current shoreline.

    Honestly, if every single ice cap in the world melted, your house's position relative to the shoreline would be one of the least significant effects.

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by gbaji View Post
    Honestly, if every single ice cap in the world melted, your house's position relative to the shoreline would be one of the least significant effects.
    Not to the people living in it, it wouldn't.

    Don't get me wrong, I don't think it's a very plausible scenario, at least not in the next century or two. Just wanted to point out that "significant" is very much a matter of perspective.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by gbaji View Post
    Does anyone actually believe that all the ice caps on the entire planet will actually melt entirely?
    Yes? This has often occured during Earth's history. In fact, Earth has more often had no ice than ice. And if you look at what temperatures were then, and what temperatures are now, we're not far off.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    I think the bigger uncertainty than how much ice there is, is what proportion of that ice is floating. Floating ice, when it melts, won't change the water level, but ice which is currently sitting on top of land will. And nobody really knows exactly where Greenland's real coastline, for instance, actually is.

    But yeah, thermal expansion of liquid water is also a big factor, so you'd have to figure how much the overall average temperature would have increased at the point where "all the ice caps have melted".
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by Chronos View Post
    I think the bigger uncertainty than how much ice there is, is what proportion of that ice is floating. Floating ice, when it melts, won't change the water level, but ice which is currently sitting on top of land will. And nobody really knows exactly where Greenland's real coastline, for instance, actually is.

    But yeah, thermal expansion of liquid water is also a big factor, so you'd have to figure how much the overall average temperature would have increased at the point where "all the ice caps have melted".
    The majority of Earth's land based ice is held in the East Antarctic Ice Sheet. Because of Antarctica's global position and the circumpolar current surrounding it, the amount of warming necessary to completely eliminate that ice is quite extreme. Something like 7.5 C increase is estimated as necessary and even then complete loss would take 1000-10000 years.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by Mechalich View Post
    The majority of Earth's land based ice is held in the East Antarctic Ice Sheet. Because of Antarctica's global position and the circumpolar current surrounding it, the amount of warming necessary to completely eliminate that ice is quite extreme. Something like 7.5 C increase is estimated as necessary and even then complete loss would take 1000-10000 years.
    Does that count as "far off" or "not far off"?

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by Eldan View Post
    Some of the difference might be how much thermal expansion of the ocean you figure in.
    I'm pretty sure those numbers are with thermal expansion. They are too massive to be just the current ice volume.

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Sure, it's just additional factors, which introduce a bit more uncertainty. To explain why the estimates differ.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by Bohandas View Post
    Googling the question gives me three conflicting figures - 195 feet (NASA), 216 feet (National Geographic), or 230 feet (US Geological Survey).

    My family's house is 223 feet above sea level, I'm trying to figure out if a worst case scenario means that we're screwed or if it means that we're rich
    At that altitude, you'd be fine, most likely. All numbers like this are estimates to some degree. We have some measurements of ice depth and what not, but often an average is relied on for a given area, and real numbers can be a shade off.

    Quote Originally Posted by gbaji View Post
    Does anyone actually believe that all the ice caps on the entire planet will actually melt entirely?
    Not in anything like a reasonable timeframe, such that the house would matter. 223 feet is a *ton* of sea level rise. It's just a fun hypothetical. Real loss of this magnitude would take very long timeframes and drastic changes.

    But unrealistic hypotheticals remain interesting. I've certainly considered many disaster movies from the perspective of if that happened to me, even where the scenario is something impossible like zombies.

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by Tyndmyr View Post
    At that altitude, you'd be fine, most likely. All numbers like this are estimates to some degree. We have some measurements of ice depth and what not, but often an average is relied on for a given area, and real numbers can be a shade off.
    It's also worth noting that many sources also just report how much ice from the caps/fields/sheets are "melting". But that's counting water runoff basically, and is only telling half the story (and the more alarming half). There's also regular yearly gains to those ice caps via fresh snow packing on the top/center. Just counting up how much melts and therefore decreases total volume of ice, without including how much snow adds to the volume of ice make things seem more drastic (but also inaccurate if we're actually worried about the "whole thing disappearing"). That's not to say that the ice hadn't decreased in total volume over the last century (it has, quite measurably), but not nearly as much as might be implied by just looking at melt rates.

    Quote Originally Posted by Tyndmyr View Post
    Not in anything like a reasonable timeframe, such that the house would matter. 223 feet is a *ton* of sea level rise. It's just a fun hypothetical. Real loss of this magnitude would take very long timeframes and drastic changes.
    Yup. And any major coastline changes from seal level changes will be gradual enough that they will be almost lost in the normal geological changes over time. Land is not static. It flows. Slowly, but it does. Just ask any geologist friends you have. Homes are removed/destroyed regularly by sea cliff or hillsides collapsing/flowing over time. Homes being removed/destroyed by gradual water level rise is much the same.

    The odds of some kind of dramatic/sudden change that causes massive waves of water or something are extremely unlikely. And far more likely (and frequently) to also be caused by land shifts (ie: Tsunami effects) than glacier run off. Humanity somehow manages to adjust ourselves to all of these other natural forces that cause problems for us all the time. So yeah. Water level rise from this is more or less just static in the signal.

    Quote Originally Posted by Tyndmyr View Post
    But unrealistic hypotheticals remain interesting. I've certainly considered many disaster movies from the perspective of if that happened to me, even where the scenario is something impossible like zombies.
    Hah. Ok. I like to do those "what if" stuff to. So totally get it! But then again, I also love watching and laughing at disaster movies too. Yes. I'm looking at you Dante's Peak. Although, I did really like the Stallone one. Um... Daylight I think? Dunno why. It's just kinda neat. Has its silly bits as well though. Honestly think "totally unrealistic action sequences" are a pre-requisite for these kinds of films.

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    There are 24500 million billion kg of ice caps (source: https://climategen.org/blog/how-much...on-antarctica/)

    The earth surface is 510 million square kilometers, 71% is ocean, so basically 362 million square kilometers

    1kg of ice melts into 1 liter of volume (not perfectly exactly, but close enough a ballpark estimation).

    (24500000000000000000 liters) / (362 million km²) = ~67 meters (plus minus a couple of meters for sure)

    Edit- You are in the danger zone @Bohandas. 223 feet is 67 meters so you'll be right on the new coastline
    Last edited by Mastikator; 2023-05-29 at 07:09 AM.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by Mastikator View Post
    There are 24500 million billion kg of ice caps (source: https://climategen.org/blog/how-much...on-antarctica/)

    The earth surface is 510 million square kilometers, 71% is ocean, so basically 362 million square kilometers

    1kg of ice melts into 1 liter of volume (not perfectly exactly, but close enough a ballpark estimation).

    (24500000000000000000 liters) / (362 million km²) = ~67 meters (plus minus a couple of meters for sure)

    Edit- You are in the danger zone @Bohandas. 223 feet is 67 meters so you'll be right on the new coastline
    With numbers that big the differences in volume with temperature start to matter. As do the increase in sea area from rising seas. How quickly it happens also matters since coral atolls can grow upward at about the same speed that sea level is currently rising (so even if we melted all the ice caps over the next 1000 years you would probably still have coral atolls in the pacific where you have them now).
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by Rockphed View Post
    (so even if we melted all the ice caps over the next 1000 years you would probably still have coral atolls in the pacific where you have them now).
    Doubtful, because coral dies if the sea temperature rises and stays risen. More likely there would be new atolls adorning the newly submerged lands at less tropical latitudes.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by veti View Post
    Doubtful, because coral dies if the sea temperature rises and stays risen. More likely there would be new atolls adorning the newly submerged lands at less tropical latitudes.
    Corals need the right amount of light, temperature and acidity. Most likely there won't be corals in a thousand years, or much life in the ocean in general for that matter, what with the ongoing and accelerating biodiversity collapse and all.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by Mastikator View Post
    Corals need the right amount of light, temperature and acidity. Most likely there won't be corals in a thousand years, or much life in the ocean in general for that matter, what with the ongoing and accelerating biodiversity collapse and all.
    Coral diversity is fairly high. There are deepwater corals in addition to shallow reef-building corals, and even within reef-based clades there's considerable variability. Massive corals, such as brain coral, have far greater tolerance and durability compared to branching corals.

    Corals will survive, they'll migrate away from the tropic to new sites as the climate changes, as they have before, and deep water forms will endure and potentially recolonize shallow locations. Coral reefs, however, require centuries or millennia to form. It's possible that all extant coral reefs will be damaged beyond repair and they will not be able to reform until the climate stabilizes in a few dozen millennia. Note that other organisms may fill in the gap. Certain clams, sponges, and other organisms can also build reefs under different conditions from corals and may become dominant as circumstances change.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by veti View Post
    Doubtful, because coral dies if the sea temperature rises and stays risen. More likely there would be new atolls adorning the newly submerged lands at less tropical latitudes.
    Would the actual overall sea temperature increase, decrease, or stay the same? Ice caps trap "frozen water" in various locations on the earth. Somewhat by definition, the temperature of the water that melts and runs off from these ice caps/sheets/whatever is likely somewhat colder than the average of all of the rest of the water on the planet.

    I think it's overly simplistic to just say "here's a global average temperature", and "here's the new global average temperature", and thus concluding that "all water, everwhere" must increase in temperature to the same degree. Setting aside that we're generally measuring air/surface temperatures with the aforementioned measurements, we're also shifting what is more or less a big heat sink (cold sink?) from where it is, to other places on the planet.

    It's entirely possible to model this in a way in which air temperatures rise to a point where ice caps melt, but actual overall liquid water temperatures decrease as a result. And, ironically, this effect could occur in exact proportion to the sea level rise we started out talking about. Frozen water (ice) floating on water doesn't change the level of the water when it melts. Only ice on land surfaces does. But that ice is not melting because of an increase in water temperature around it (can't, because it's not floating on water). That ice is melting due to air temperatures around it. But it's running off into already liquid water around the globe, which should actually decrease that temperature overall.

    Not to say that doesn't introduce other potential problems as well, but just pointing out that it's not such a simple thing as "everything gets hotter".

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by gbaji View Post
    Would the actual overall sea temperature increase, decrease, or stay the same? Ice caps trap "frozen water" in various locations on the earth. Somewhat by definition, the temperature of the water that melts and runs off from these ice caps/sheets/whatever is likely somewhat colder than the average of all of the rest of the water on the planet.

    I think it's overly simplistic to just say "here's a global average temperature", and "here's the new global average temperature", and thus concluding that "all water, everwhere" must increase in temperature to the same degree. Setting aside that we're generally measuring air/surface temperatures with the aforementioned measurements, we're also shifting what is more or less a big heat sink (cold sink?) from where it is, to other places on the planet.

    It's entirely possible to model this in a way in which air temperatures rise to a point where ice caps melt, but actual overall liquid water temperatures decrease as a result. And, ironically, this effect could occur in exact proportion to the sea level rise we started out talking about. Frozen water (ice) floating on water doesn't change the level of the water when it melts. Only ice on land surfaces does. But that ice is not melting because of an increase in water temperature around it (can't, because it's not floating on water). That ice is melting due to air temperatures around it. But it's running off into already liquid water around the globe, which should actually decrease that temperature overall.

    Not to say that doesn't introduce other potential problems as well, but just pointing out that it's not such a simple thing as "everything gets hotter".
    The thermal reservoir represented by all surface water on Earth is enough to lag seasonal temperature changes by 2-3 months (which is why February, not December, tends to be the coldest month). So the effects of adding a fixed amount of lower-than-average-temperature water to the ocean aren't going to persist more than a few years at most, not create a permanent shift in equilibrium.

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by gbaji View Post
    Would the actual overall sea temperature increase, decrease, or stay the same? Ice caps trap "frozen water" in various locations on the earth. Somewhat by definition, the temperature of the water that melts and runs off from these ice caps/sheets/whatever is likely somewhat colder than the average of all of the rest of the water on the planet.
    Ice is melting into the sea because the sea carries enough heat to melt it. For many years now, we have seen a steady decline in sea ice around both poles. (Not "steady" as in "continuous", obviously. Ice still increases in winter and recedes in summer. But each summer it's been receding further, and each winter it recovers less than previously.)

    Obviously, the melting ice cools the sea around it. But that effect has not been enough to halt this trend over some decades now. Each summer, despite the cooling added by the ice previously melted, the sea still comes back with enough heat to push it back further. It's like a war of attrition, and the ice is definitely losing.

    That implies an ongoing, long term rise in the total amount of heat stored in the ocean. (Indeed, for the ice caps to melt, as we're positing here, that has to be true.)

    Of course there will still (presumably) be local variations, currents that warm or cool some patches of the ocean more than others at the same latitude. I guess someone somewhere may be able to make some decent guesses at where those currents might flow, in this world we're imagining - but I am not that person. I just think it would be a remarkable coincidence if they just happened to maintain a perfect coral-growing temperature around, say, Tahiti, over a period of centuries, while the average temperature of the oceans around rose through several degrees.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by gbaji View Post
    Would the actual overall sea temperature increase, decrease, or stay the same? Ice caps trap "frozen water" in various locations on the earth. Somewhat by definition, the temperature of the water that melts and runs off from these ice caps/sheets/whatever is likely somewhat colder than the average of all of the rest of the water on the planet.

    I think it's overly simplistic to just say "here's a global average temperature", and "here's the new global average temperature", and thus concluding that "all water, everwhere" must increase in temperature to the same degree. Setting aside that we're generally measuring air/surface temperatures with the aforementioned measurements, we're also shifting what is more or less a big heat sink (cold sink?) from where it is, to other places on the planet.

    It's entirely possible to model this in a way in which air temperatures rise to a point where ice caps melt, but actual overall liquid water temperatures decrease as a result. And, ironically, this effect could occur in exact proportion to the sea level rise we started out talking about. Frozen water (ice) floating on water doesn't change the level of the water when it melts. Only ice on land surfaces does. But that ice is not melting because of an increase in water temperature around it (can't, because it's not floating on water). That ice is melting due to air temperatures around it. But it's running off into already liquid water around the globe, which should actually decrease that temperature overall.

    Not to say that doesn't introduce other potential problems as well, but just pointing out that it's not such a simple thing as "everything gets hotter".
    I'm not a climate scientist so I'll defer to the climate scientists and their data at NASA. https://climate.nasa.gov/ The top middle link "Global Temperature" opens into two graphs, to the left you see the rising average global temperature over time, to the right you see a heat map that you can play over time.
    One thing that is striking to me is that the north pole, and in particular Greenland is getting a lot hotter. If the entire greenland glacier were to melt the sea level would rise by about 7 meters.
    However luckily the south pole is not getting extra hotter, just normal hotter, so melting all of that away is going to take a lot longer.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quoth gbaji:

    Yup. And any major coastline changes from seal level changes will be gradual enough that they will be almost lost in the normal geological changes over time.
    We're not talking about geological timespans, here. We're talking about timespans of a century or less. The changes won't be lost in the noise; they'll be enough that an old person will be able to visit their childhood home and see the difference.
    Quoth Mechalich:

    Corals will survive, they'll migrate away from the tropic to new sites as the climate changes, as they have before,
    Again, remember the timescales. How quickly can coral migrate? They're not exactly an organism renowned for their speed. Most previous climate changes happened much slower, slow enough that even coral migration rates were fast enough. The climate hasn't changed as quickly as it's changing now at any point since 65 million years ago, and we all know how well living things adapted to that.
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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by veti View Post
    Ice is melting into the sea because the sea carries enough heat to melt it.
    Not the ice that would raise the sea level if melted though. Which was the precise point I made previously. That *can't* be caused by sea water termperatures, because that ice isn't actually resting on (floating on) the sea.

    Quote Originally Posted by veti View Post
    For many years now, we have seen a steady decline in sea ice around both poles. (Not "steady" as in "continuous", obviously. Ice still increases in winter and recedes in summer. But each summer it's been receding further, and each winter it recovers less than previously.)
    Sure. But that's not relevant to the question of "how much would sea level rise if the ice caps totally melted". Total sea rise from ice caps floating on the actual sea melting is zero. It's only the ice caps on land (antartic and various glaciers and ice peaks) that can increase sea level via melting. I actually had to double check the definition before posting in this thread because I wasn't sure if "ice caps" included "stuff on land", since my first response to the question was "zero".


    Quote Originally Posted by veti View Post
    That implies an ongoing, long term rise in the total amount of heat stored in the ocean. (Indeed, for the ice caps to melt, as we're positing here, that has to be true.)
    Again. Be very careful with the teminnology. The term "ice caps" does not just mean "ice floating on water", which I suspect is what many people assume when someone talks about the "ice caps melting".

    Quote Originally Posted by Chronos View Post
    We're not talking about geological timespans, here. We're talking about timespans of a century or less. The changes won't be lost in the noise; they'll be enough that an old person will be able to visit their childhood home and see the difference.
    Except we actually are. Certainly if we're talking about actual total ice cap melt. Someone posted earlier a time frame in the 1k to 10k year range for this to happen.

    That's not going to be an issue for anyone living today who is worried about the house they are living in right now. Which was the point.

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by gbaji View Post
    Not the ice that would raise the sea level if melted though. Which was the precise point I made previously. That *can't* be caused by sea water termperatures, because that ice isn't actually resting on (floating on) the sea.
    Glaciers flow. Ice continously flows down the Antarctic land mass to the sea. In years past this used to be a very slow process, because the floating portion of the ice sheet slowed down the flow upstream. But with the floating portion fading away, the flow from land accelerates dramatically. The replenishment of ice from snow in the interior of the Antarctic can't keep up.

    Sure. But that's not relevant to the question of "how much would sea level rise if the ice caps totally melted". Total sea rise from ice caps floating on the actual sea melting is zero.
    No it's not, because ice from the land slides down into the sea. The less ice is already there in its path, the easier this passage gets. And the warmer air (resulting, locally, from "air not having to cross a massive floating ice sheet before it reaches inland") increases surface melting, which then sinks through the ice and helps to lubricate its motion.

    The fact that most of the ice is floating when it actually melts is not nearly so reassuring as you seem to think. It's a bit like saying "only the outer layer of my ice cube is melting, the centre is quite safe".
    Last edited by veti; 2023-06-06 at 02:38 PM.

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    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by Chronos View Post
    Again, remember the timescales. How quickly can coral migrate? They're not exactly an organism renowned for their speed. Most previous climate changes happened much slower, slow enough that even coral migration rates were fast enough. The climate hasn't changed as quickly as it's changing now at any point since 65 million years ago, and we all know how well living things adapted to that.
    There have been some pretty big and rapid climate change spikes before. The Paleocene-Eocene Thermal Maximum occurred very quickly. Yes, in the worst-case scenario it's possible that all extant reefs will die and there will be a period without any reefs before corals are able to migrate and a very large percentage of the extant coral species will be unable to endure as remnant populations of small polyp clusters while migrating to new locations, but corals, as a whole, will almost certainly survive and will eventually produce new reef-building forms down the line in new regions.

    That's still extremely bad, since the loss of all extant coral reefs is, from the perspective of human civilization and ecosystem services, considerably more important than the extinction of a large percentage of extant coral species, but it's a somewhat different outcome.
    Now publishing a webnovel travelogue.

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    Bugbear in the Playground
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    Aug 2022

    Default Re: How much would the sea level rise if the ice caps totally melted?

    Quote Originally Posted by veti View Post
    No it's not, because ice from the land slides down into the sea.
    Which is functionally identical to the same quantity of ice melting and running off into the sea. Which counts as "non floating ice melting". The fact that it may run off while still in solid form, and float for a while doesn't change the fact that at some point that volume of ice was resting on land, and thus when it "melts" it will increase the sea level (and introduce something "cold" into the sea water at the same time).

    I already talked about antartic ice and land glaciers and ice peaks. Those are all sources of melting ice that will raise the sea level as they melt. Because they all are "right now" on land. The exact process by which they move from being "on land" to "on/in the sea" doesn't matter. Any movement of water (in any form) from being "on land" to "on/in the sea" will increase the water levels of the sea. The same process happens, every day, all day long on every single river and stream that terminates in an ocean anywhere on the globe. Yet, shockingly, we don't despair that this will massively raise the water level, nor despair that all the water on land will "run out" (well, we do to some degree, but that's another topic). We trust that other components of our ecosystem will evaporate that water (which, ironically "increased heat" helps facilitate), move it around in the air, and then deposit it back on land via this thing called "rain". And at high altitudes, it'll deposit it in the form of "snow", which tends to form into ice, and sit around for quite some time. And we repeat the process.


    Quote Originally Posted by veti View Post
    The fact that most of the ice is floating when it actually melts is not nearly so reassuring as you seem to think. It's a bit like saying "only the outer layer of my ice cube is melting, the centre is quite safe".
    Incorrect. The moment ice begins "floating" on water, it has already raised the water level all that it's going to. Ice displaces the exact same amount water as it will melt into over time.

    So from the point of view of "how much will the sea rise", currently floating ice doesn't count at all.

    However (and this was the point I was making about ocean temperatures), floating ice *does* count with regards to temperature effects. In precisely the same way that a cube of ice doesn't change the level of the water in your glass as it melts, but it *does* change the temperature of the water (downward) as it melts.

    Simple science test: Pour a glass of room temperature water. Drop a couple ice cubes in it. Measure the temperature of the water, and the height of the water in the glass. Leave it out until the ice melts. Check the water level. It will be the same as it was prior to the ice melting. Check the temperature. Assuming "room temperature" has remained constant, the water will be colder than it was when you first measured it.

    Obviously, there are more factors involved here. I'm just pointing out that the effect of melting ice over time should actually reduce the water temperature, not increase it (everything else staying the same). It's the air temperature that is melting the ice, not the water temperature around it. So what you are doing is moving a heat sink from where it is now (either on land, or floating above the water) *into* the water. Which will draw heat out of the water as a result. Now, whether this actually offsets other changing factors is another matter. I'm just talking about the direct relative temperature effect of melting that ice. Doubly so for ice that is not actually floating on the water, since it's not in direct contact (and thus not affecting the water temperature at all) right now, but will be when melted/moved/whatever from "on land" to "on/in water".

    It's actually a funny topic because I've run into people who don't seem to get the concept that ice only cools things by melting (for normal temperature ranges for "ice" that is). That's how it transfers heat. I once watched a friend of mine who was trying to peel peaches for something, and he needed an ice bath as part of the process. And he kept talking about how every time he's tried this in the past it was always so hard to peel the peaches, they always got stuck, tore apart, etc. I watched as he got his ice out and into a bowl, then stood there with his peaches waiting for the water to boil so he could drop them in for a minute, and then shock them in the ice bath. I'm like "um... Are you going to put water in the bowl with that ice". And his response was "I don't want the ice to melt before I put the peaches in, so I'm waiting until right before to add the water".

    /facepalm

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