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North Greenland Ice Shelves Have Lost 35% of Their Volume In Last Half-Century, Study Finds (cbsnews.com) 113

Posted by BeauHD from the hope-you-can-swim dept.
An anonymous reader quotes a report from CBS News: Scientists have long thought that the glaciers in North Greenland have been stable -- a vital condition, as they contain enough ice to raise the sea level by nearly 7 feet. But a new study published on Tuesday found that ice shelves in the region have lost more than a third of their volume in the last half-century because of rising temperatures -- and if it continues, scientists say there could be "dramatic consequences" for glaciers, and the planet. Using thousands of satellite images and climate modeling, the study, published in Nature Communications, found that North Greenland's ice shelves "have lost more than 35% of their total volume" since 1978.

Ice shelves are the part of ice sheets -- a form of glacier -- that float over water. Three of those shelves in North Greenland have "completely" collapsed, researchers said, and of the five main shelves that remain, they said they have seen a "widespread increase" in how much mass they have lost, mostly due to the warming of the ocean. One of the shelves, called Steenbsy, shrank to just 34% of its previous area between 2000 and 2013. Along with the loss of overall ice shelf volume, scientists said the area of floating ice decreased by more than a third of its original extent since 1978. This observation could pose a major problem, as the Greenland ice sheet is the second-largest contributor to sea level rise. From 2006 to 2018, scientists noted that the single sheet was responsible for more than 17% of sea level rise in that period.
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North Greenland Ice Shelves Have Lost 35% of Their Volume In Last Half-Century, Study Finds More

North Greenland Ice Shelves Have Lost 35% of Their Volume In Last Half-Century, Study Finds

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  • I blame artisanal water (Score:4, Funny)

    by ruddk ( 5153113 ) on Wednesday November 08, 2023 @08:16AM (#63989587)

    They mostly come out at night, with their big ships, stealing our ice and selling it bottled for a premium price in California!

    • They mostly come out at night, with their big ships, stealing our ice and selling it bottled for a premium price in California!

      So, ice pirates?
      https://en.wikipedia.org/wiki/... [wikipedia.org]

      I didn't see the movie from end to end, only bits and pieces that people posted to YouTube, but that mention of stealing ice in the night brought that movie to mind. A more real world concern I've heard of is foreign cargo ships coming to freshwater rivers and lakes in the USA and filling up their ballast tanks with water after dropping off cargo, the accusation being that they were stealing our water for their use. I don't know what is supposed to be done

      • Ice Pirates was a decent movie, end to end. Nto sure if it holds up over time though, since it's been a very long time since I saw in the decades before I got good taste.

        Playing Starfield recently, I saw the heat leeches and my very first thought was "Space herpes, you didn't tell me you had space herpes!" And a quick check online shows I'm not the first to make the connection.

    • We prefer Icelandic water, because they have artisans who chip off the ice.

  • In other news... (Score:5, Insightful)

    by jd ( 1658 ) <imipakNO@SPAMyahoo.com> on Wednesday November 08, 2023 @08:16AM (#63989595) Homepage Journal

    The UK is increasing fossil fuel use, Europe is abandoning commitments to green technology, some States impose taxes on people with solar panels in order to boost sales by the power companies, and US sanctions on China eliminate the West's leverage to get China to stop polluting.

    We're doomed.

    • We’re not doomed, but we’ve decided to let climate change hit us like a freight train and deal with the damage later. We’re inventive and adaptive. We’ll survive. But it’s gonna be hella disruptive.

      It’s pretty much a conscious decision that we’ve made as a species. Scientists and engineers need to be researching geoengineering methods, because we’re going to need them next century.

    • So what are you doing to help STOP THE DOOM?

      Inquiring minds want to know.

      • Re: (Score:2)

        by jd ( 1658 )

        I've done what I can. I exclusively use mass transit, I have reduced meat consumption with an eye to possibly phasing it out if I can find a way that's healthy, my back garden looks like a forest for all the trees I've planted out, I have no kids, I minimise power and water consumption, I have solar panels, I recycle, I work from home as much as my job permits, I buy books second-hand, food purchases are from geographically local sources where possible, warm clothes take precedence over turning the heating

  • Comment removed based on user account deletion

    • Re: (Score:2)

      by dbialac ( 320955 )
      Good old bait and switch in the article. Ice shelves don't raise oceans because they're already displacing the water.

      • Re: (Score:2, Informative)

        by Geoffrey.landis ( 926948 )

        Good old bait and switch in the article. Ice shelves don't raise oceans because they're already displacing the water.

        The actual paper referenced says that the effect discussed is that ice shelves buttress the glaciers, and slow down their flow to the sea, so loss of ice shelves results in faster melting of the glaciers.

        However, I agree, the summary is misleading to people who don't already know that.

  • The ice shelf force-submerges a large part of Greenland under the ocean. If that shelf melts, I Greenland will rise out of the ocean. I have to assume that will cause ocean levels to go down somewhat.

    • Re: What if Greenland rises out of the ocean? (Score:4, Insightful)

      by beelsebob ( 529313 ) on Wednesday November 08, 2023 @09:00AM (#63989653)

      Why would it? The pad of ground under Greenland and around it takes up more volume than Greenland does. It would cause water levels to go up further!

    • Uh, was this serious?

      The volume of glacial meltwater would vastly exceed the much smaller isostatic adjustment effect.

    • Re: (Score:3)

      by quenda ( 644621 )

      The ice shelf force-submerges a large part of Greenland under the ocean.

      No. That is an ice sheet and is of course huge.

      Ice shelves are the bottom parts of glaciers that float on the water. The are much, much smaller, and this is where the 35% loss was.
      Also, since they are floating, they do not directly affect ocean levels when they melt.
      The fear seems to be that with the shelves melting, the glaciers will flow more quickly into the ocean. The glaciers represent 2.1m of ocean level.

      The Greenland's ice sheet completely melted, ocean levels would rise seven metres just from that

    • Yes, in the same way as bailing water out of a boat does not alter the level of the lake. But as far as I know this geological bounce-back is not instantaneous, but happens over geological timescales. The "viscosity" of the earth's crust is higher than water's.
    • If you have a pond three feet deep with a little island 1 foot tall in the middle and you increase the height of that island to 2 feet, does the level of water in the pond go up, down, or stay the same?

  • Scientists have long thought that the glaciers in North Greenland have been stable -- a vital condition, as they contain enough ice to raise the sea level by nearly 7 feet. But a new study published on Tuesday found that ice shelves in the region have lost more than a third of their volume in the last half-century because of rising temperatures

    So seas have risen by 1/3 * 7 feet =~ 2.3 feet?

    • Re: Come and sea (Score:5, Informative)

      by beelsebob ( 529313 ) on Wednesday November 08, 2023 @09:02AM (#63989661)

      No, since most of the ice that has melted so far has been the ice shelf, which was already floating. The sea level will rise when the stuff supported by land melts.

    • Misleading text (Score:4, Informative)

      by Geoffrey.landis ( 926948 ) on Wednesday November 08, 2023 @09:08AM (#63989675) Homepage

      So seas have risen by 1/3 * 7 feet =~ 2.3 feet?

      No. The article text is misleading. Note the highlighted words:

      Scientists have long thought that the glaciers in North Greenland have been stable -- a vital condition, as they contain enough ice to raise the sea level by nearly 7 feet. But a new study published on Tuesday found that ice shelves in the region have lost more than a third of their volume...

      Ice shelves are not glaciers. It's the ice shelf that has lost volume, not the glaciers.

      Ice shelves are floating, and hence loss of ice shelf volume does not directly affect sea-level rise, while loss of glacier volume does. (There's an indirect effect, that ice shelves tend to stabilize the glaciers by impeding the flow of glacial ice to the ocean.)

      • The big question is then, as the glaciers move towards the sea is the whole glacier slipping down, exposing the top of mountains as it goes down or is new ice forming above?

        If the former then I'll have beachfront property. If the latter then no big deal as new ice is formed taking out the same volume of moisture from the surround air/ocean to keep things equal.

        These scare articles never cover what's really happening.

        • The big question is then, as the glaciers move towards the sea is the whole glacier slipping down, exposing the top of mountains as it goes down or is new ice forming above?

          Glaciers flow like rivers. (Very slow rivers). In equilibrium, the flow toward the sea is exactly matched by snowfall being compacted and turning to ice at the source.

          Unless there is an increase in snowfall that doesn't melt in summer, to feed enough new ice to the glacier to be equal to the increase in glacial flow and subsequent melting, sea level will rise.

          ...These scare articles never cover what's really happening.

          Snowfall and snow melting prediction would be a quite different topic.

          • > Snowfall and snow melting prediction would be a quite different topic.

            Not necessarily. If for whatever reason glaciers world wide are making a rush to the sea but are growing faster on top then on the whole they are holding more water than they are releasing so sea level should actually drop.

            Or it could be the other way, I suppose. No new snow forms but they continue sliding at the same rate. That would be bad for us.

            I think it does matter. Everything is connected.

            • Oh, it matters, but it's a different topic.

              The paper being discussed, reporting measurements of ice sheet volume, is not the place to expect meteorological predictions of snowfall on the land mass. And since melt rate of the ice shelves does not affect the snowfall and snow melt rates, the two questions can be addressed separately.

              • Ok sure but then they can't make th4 conclusion that sea level will rise without addressing the rest of what impacts sea level.

                • Ok sure but then they can't make th4 conclusion that sea level will rise without addressing the rest of what impacts sea level.

                  The increase in glacial melt causes a rise is sea level. That doesn't mean that other effects could cause a decrease in sea level. Snowfall and snow melt rate are effects entirely different from the sea ice being discussed.

                  • Dude, that's like saying driving your car will empty your tank and leave you stranded on the side of the road without taking into account all the gas stops you took on your journey.

                    • No, it's like saying that starting a fire will make you warmer and having some idiot say "but what if at the same time you fill your house with ice cubes! Then you will get colder! You have to account for that!"

                      The fact that one thing raises sea level in no way implies that other things can't lower sea level.

                    • No, those are not the same. There is a direct link in th cycle between new ice pulling water out from the atmosphere and therefor also the sea and sea levels.

                      There is a direct link between my gas tank level, how much I drive and how much gas I add along the way.

                      Your ice cube fire analogy is just silly.

                      You've made it clear the scientists are not looking at the full cycle and it bothers you that I caught it.
                      There's nothing more to be said but go ahead and take the last word. I'm done here.

                    • No.

                      Snowfall is a different phenomenon from melting of glacial ice shelves, and is studied by different scientists.

                    • Yeah yeah whatever. There is no cycle. There is no effects from other things. We just chop it all up into little pieces, study the one piece, ignore the others and claim some result that relies on all the pieces.

                      You already said that a few times. Yawn. Bored now. You're boring.

                    • Ice shelves are not glaciers as has been pointed out.

                      And as you didn't bother to comprehend I never said there was extra snow.

                      You're an AC so I won't bother to explain your idiocy and further. You're lucky I replied at all.

                    • Hi AC dumbass, you have completely missed the entire conversation here. Because you're an AC and therefore a dumbass I won't bother explaining. It's all right there in plain English. Go re-read it for comprehension. Maybe my 8th grade level English target is too high for you. I'll do 1st grade for you, "you're a dummy head who can't read!"

                    • Did AC say something? Listening... nope! Nothing an AC said is worth a real reply nor would I look at your link. You're wasting your time.

                      Reply with your regular name and you'll get real replies.

                      Your toilet brush must be fucking brilliant.

            • Why would precipitation at the top of the glaciers increase just because the glaciers are moving? Explain your reasoning here for the climate at the top of the glaciers changing so exactly as to result in what you suggest.

              • It would not. I never said that.

                • Re: (Score:2)

                  by q_e_t ( 5104099 )
                  You said:

                  If for whatever reason glaciers world wide are making a rush to the sea but are growing faster on top then on the whole they are holding more water than they are releasing so sea level should actually drop.

                  But we know glaciers in most parts of the globe, including Greenland, are losing mass. For them to gain mass would either require reduced flow (the reverse of what is observed here with melting ice shelf) or a change in the climate at the head of the glacier, which has not yet been observed, to increase deposition of ice. Only in a few areas of Antarctica, and not even all of that continent, currently shows increased cold precipitation in the area where glaciers originate or along their length. So

                  • We know that? Are there huge runoffs all over the world flooding river banks and drowning towns?

                    And it wasn't my "idea" that it is happening. My "question" was have they taken new snow/ice into account. And the answer is apparently no. Is there none? Is there a lot? What is a lot, anyway? How does that rate compare to loss rate? Will the glaciers already be gone 10 years ago as per that grifter Gore or will it take 2000 years at current rate? And if it does take hundreds or thousands of years then

                    • Re: (Score:2)

                      by q_e_t ( 5104099 )

                      We know that? Are there huge runoffs all over the world flooding river banks and drowning towns?

                      Yes, we do know it as we know where glaciers used to end and they don't end there any more. No, there's not flooding as it happens over decades. You really need to get yourself educated.

                      And it wasn't my "idea" that it is happening. My "question" was have they taken new snow/ice into account.

                      Yes, it's routinely measured. That's why we know it has increased in parts of Antarctica and not elsewhere as the scientists have thought to measure it.

                      And the answer is apparently no.

                      No, the answer is they measure it

                      As you well know the shelf melting doesn't change ocean levels whereas land mass ice melt does. Thus the intentional confusion so we all go "oooooh scary!"

                      And the paper doesn't say it will increase it, but will allow glaciers, which are on land to calve more quickly which is the mechanism for in

  • The average American gained about 35% in volume in the past 50 years.

  • they contain enough ice to raise the sea level by nearly 7 feet. But a new study published on Tuesday found that ice shelves in the region have lost more than a third of their volume in the last half-century because of rising temperatures

    So, there should have been a ~2 foot rise in sea levels over the same period. But, what we have recorded is a ~4 inch rise in global sea level.

    The seeming discrepancy here is due to the badly written article and the lack of clear differentiation between floating ice shelf(melting) and on-land glacier(not so much). Floating melt does not change sea levels. Land based melting could.

    • There's also the issue that some ice has been forming at the same time. While there's a net reduction in total ice, the individual changes aren't all in the negative column.

      Certainly, though, when you have such an obvious and glaring discrepancy that anybody with half a brain can spot, you have to do your homework and then explain it in your article. Otherwise you are indeed just scare-mongering... which doesn't help because you're really just providing fodder for the denialists who prevent us from doing

      • The paper is fine, the article is unclear, though. It may assume a knowledge of the distinctions of ice location terminology. I read quite a bit of this stuff and I was confused until I reread it and checked other sources that do better at summarising papers.
    • No, the article is talking about the ice shelf reducing, not the ice sheet. It's badly worded. The underlying scientific paper is much clearer

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