Antarctica and “alarming” Sea Level Rise

By Rud Istvan,

WUWT reader KS of North Dakota emailed a request to ctm based on reading ‘alarming’ Wired journalism concerning $50 million being spent to further study the ‘dangerous’ Thwaites glacier in Antarctica. KS asked if WUWT could perhaps produce a factual overview. ctm asked me to provide it, since I had written an extensive essay ‘Tipping Points’ in ebook Blowing Smoke on this very sea level rise (SLR) subject (and more). What follows is a lightly rewritten and slightly expanded/updated excerpt for KS and the rest of WUWT.

There are only three ice sheets in the world with the potential to accelerate SLR to alarming levels: Greenland, the East Antarctic Ice Sheet (EAIS) and the West Antarctic Ice Sheet (WAIS).

In ‘theory’ Greenland could melt, since there is observed summer melting. It cannot calve (slide into) into the sea (although there are fringe glaciers like Jacobshaven that do, the Titanic sinking being evidence) because Greenland is bowl shaped. At the observed average annual ice mass loss of the past ~2.5 decades (from 1990) Greenland would theoretically take 27000 years to melt. At the ice mass loss rate since 2000, it would only take 14000 years and would increase SLR by a distinctly unalarming ~0.5mm/yr. In reality, given Greenland’s latitude and central ice sheet elevation, melting is impossible—as ice cores reaching back to the Eemian prove. Calculations and references behind this brief summary are provided in ‘Tipping Points’.

With Greenland geophysically debunked, SLR attention turned to Antarctica. [i] Whether Antarctica is net gaining or losing ice is a matter of dispute between NASA (gaining) [ii] and NOAA (losing). [iii] It is a big complicated place. A recent NOAA ice loss estimate is: [iv]

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EAIS maybe gaining, WAIS losing, the Peninsula about even. Most of EAIS is anchored by mountains, so cannot ever ‘slide off’. Nor can it ever melt so long as Antarctica sits over the South Pole.

Any SLR alarm has to be found in WAIS, where the general slope is from the Transarctic Mountain divide down to the sea. Some (maybe 2/3) in theory could ‘slide off’, because WAIS cannot melt either. The rest is anchored by the coastward Executive Committee and Ellsworth mountain ranges.

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So potential WAIS instability has been the subject of much scrutiny. The main concerns were the grounded portions of the Ronne (which is not really part of WAIS but is still mostly in the Western half of Antarctica) and Ross ice shelves. (Floating shelf ice cannot raise sea level.) These have the largest volumes of grounded ice creeping out onto the seabed, although on an annual basis fresh snow replenishes most of the lost shelf ice inland at higher WAIS elevations. It is the net ice mass balance along these WAIS grounding lines that might give rise to SLR alarms.[v]

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Ronne (#1 in the following figure) is net gaining ice mass according to NASA.[vi] A 2012 ice core from the Fletcher Promontory showed Ronne remained stable during the warmer Eemian. [vii] It isn’t a SLR concern. Ross (#19) might or might not be losing ice, but it ‘holds back’ almost half of WAIS. Ross also has more ice grounded on the seabed, which if ungrounded (melted from below), would raise sea levels. For several years Ross became the Antarctic instability ‘alarm’, which is why the ANDRILL program was instigated.

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The ANDRILL program was designed to look at the underlying Ross seabed (both where the ice is grounded below sea level, and where it is floating shelf) to understand its behavior. Andrill cores and creep rates suggest it has not collapsed before (well, for at least 3 million years and all previous Pleistocene interglacials), so very likely will not now from global warming. Holocene retreat of the Ross grounding line stopped 4 millennia ago. [viii] Ross bedrock islands ‘anchor’ its grounded ice and retard seaward creep. [ix] The Ross shelf’s seaward creep has decelerated in recent decades. [x], [xi] The ANDRILL program ultimately proved Ross was not alarming either.

So ‘alarmist’ attention turned to the only other WAIS possibility, the smaller Amundsen Embayment (#21,22), which has been found to be losing ice at an accelerating rate. [xii], [xiii]

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Abetted by additional NASA PR and author interviews (Rignot of NASA JPL, “Already gone into irreversible retreat, past the point of no return”, 2014 MSM alarmist headlines were, well, alarming. Reuters reported worldwide: “West Antarctic Glaciers in irreversible thaw: rising seas[xiv] CNN said: “Ice melt in part of Antarctica ‘appears unstoppable’, NASA says[xv] MSM TV was worse. [xvi] The KS spotted Wired ‘journalism’ is simply a 2018 echo of this alarmism.

Except the media did not read these papers carefully or in context (if at all). The first paper found Pine Island Glacier (PIG, #22) plus Thwaites (#21) plus lesser Amundsen Sea glaciers have accelerating creep and are now discharging ice into the sea at ±330Gt/yr. That is (330/85) 3.9x higher than any previous estimate, for example NASA’s own from 2011 and 2012. This newest estimate is presently an outlier –but not necessarily wrong– with the likely explanation, volcanism, explained below. The second paper used computer models of Thwaites (#21) bottom melting to conclude it might become unstable in 200 to 900 years. If so, models suggested maybe 1mm/yr of additional SLR thereafter. Not ‘in coming decades’, maybe in coming centuries.

There is a deeper problem with NASA’s version of Amundsen Embayment SLR alarm. The NASA NEWS discussing these papers says the Embayment catchment basin contains enough ice to raise global sea level by 4 feet (1.2 meters). That is true; the basin has a total area of about 360,000 km2 and the ice averages 3km thick. [xvii] But for 1.2 meters of SLR, the entire catchment basin would have no ice at all. That is extremely unlikely, since the interior portions are not flowing seaward according to NASA’s own papers, and are still gaining ice. [xviii], [xix] As the preceding Amundsen Embayment catchment and following NASA illustrations show, PIG and Thwaites glaciers comprise only about 15% of the catchment basin area and less of its ice volume (ice is thicker to the interior).

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The media hoopla also ignores another paper on an ice core (F10) (drilled on the divide to Farrigno Glacier, just northwest of PIG) providing a detailed isotope derived temperature record from 1702 to 2009. [xx] F10 shows greater periods of Amundsen Embayment warming and cooling in both the 18th and 19th centuries than in the 20th. It found:

“…the effect of anthropogenic climate drivers at this location has not exceeded the natural range of climate variability in the context of the past ~300 years.”

NASA’s newest accelerated ice loss estimate may not be erroneous. A 2017 paper provided the first physical proof that the Amundsen Embayment, and in particular PIG, sits over an area of active volcanism.[xxi] Volcanic ash was found in its ice cores.

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SLR alarm remains popular in media reporting, easily suggested by images of calving WAIS glaciers and summer meltwater rushing down Greenland moulins. But it is all alarmist fantasy rather than remotely possible centennial or even millennial factual possibilities.


[i] Colville et. al., …Isotope Evidence…, Science 33: 620-623 (2011)

[ii] Zwally et. al., Mass Gains of the Antarctic Ice Sheet Exceed Losses, SCAR ISMASS 7/14/2012

[iii] Shepard et.al., A reconciled estimate of ice-sheet mass loss, Science 318:1183-1189 (2012)

[iv] NSIDC.org/cryosphere/sotc/ice-sheets

[v] Image from the Rignot Research Group, JPL and NSIDC data

[vi] See WUWT 8/20/2013, ridiculous National Geographic Statue of Liberty image

[vii] nora.nerc.ac.uk/eprint/506400

[viii] Doake (British Antarctic Survey), Ice Shelf Stability, Chapter 10 Encyclopedia of Oceans (2001)

[ix] NASA.gov/jpl/news/Antarctic-ice-sheet-201450512/#U3PDB8blvu1r

[x] Scheuchl et. al., Ice Velocity Change in the Ross and Ronne sectors…, Cryosphere 6: 1019-1030 (2012)

[xi] Hulbe et. al., Recent Changes in the flow of the Ross Ice Shelf, Earth & Planetary Science Letters 376: 54-62 (2013)

[xii] Mouginot et. al., Sustained increase in ice discharging from the Amundsen Sea Embayment, GRL: 2013GL059069 (2014)

[xiii] Joughin et. al., Marine Ice Sheet Collapse potentially underway for the Thwaites Basin, Science 344: 735-738 (2014)

[xiv] Doyle, Reuters, 5/12/2014

[xv] Hanna, CNN, 5/13/2014

[xvi] Brian Williams, NBC 5/12: 13 feet SLR in 100 years. Scott Pelley, CBS: 4 feet by 2114. Diane Sawyer, ABC: 3 feet by 2100 and Florida hard hit.

[xvii] Rignot et. al., Acceleration of Pine Island and Thwaites…, Annals of Glaciology 34: 189-194 (2002).

[xviii] Pritchart et. al., Antarctic Ice Sheet Loss…, Nature 484: 502-505 (2012)

[xix] Medley et. al., Constraining the ice mass balance…with airborne observations of snow accumulation, Cryosphere Discuss. 8: 953-998 (2014)

[xx] Thomas et. al., A 308 year record of climate variability in West Antarctica, Geophys. Res. Lett. 40: 5492-5496 (2013) available at nora.nerc.ac.uk/503527

[xxi] Iverson et. al., The first physical evidence of subglacial volcanism under WAIS, Science Reports 7, 11457 (2017)

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66 thoughts on “Antarctica and “alarming” Sea Level Rise

    • Yes, three seconds after I told an co-worker that my next cruise includes “Athens in August” and wondering if it might be a bit on the hot side…we stepped into the elevator and saw this on the TV.

      Hope they put some of that ice away for my drinks.

  1. So Greenland might melt in 27,000 years? Wouldn’t that be past the likely start date for the next Ice Age?
    Nevertheless, we should still panic!/sarc

  2. The Communist Chinese government has undertaken an aggressive policy of turning sandy coral islands that frequently were under high tide (in their former natural state) into military bases in the East china Sea. Even with much dredging of sand and re-depositing to build up these islands to build runways and hardened structures (hardened MRBM and SAM missile bunkers) and living quarters, they are still just barely above mean high tide, and a strong typhoon with a enough storm surge at high tide could cover it all with sea water them in an hour or so.

    The rich continue to buy ever more expensive properties along Miami Beach. Apparently there is little concern for SLR there. Richard Branson is re-building his little island paradise in the Virgins, devastated by Maria in 2017.

    Apparently the Chinese are not so concerned about SLR, and they do have good scientists. When the rich stop buying and building beach front property, and the Chinese stop building on coral atolls and due to SLR, then we should worry about SLR. Until then, it’s just propaganda for the ignorant masses.

    • Meanwhile in New Zealand, the lead item in the ZB national news this morning was a warning from the leader of the Insurance Council that we should all be wary of the dangers inherent in doing any construction work close to the sea as SLR is an increasing danger. Where do these idiots get their information from? Or is it just a sensible tactic from an insurance industry which wants to protect their own finances? At about 5 inches per century, I don’t think most of us should be concerned about SLR in our lifetime!

      • I look forward to the day when I can buy property insurance for more than a year ahead. The insurance industry isn’t carrying any risk here, they just want cover to up their premiums to pay their underwriters for fee increases justified by the recent series of earthquakes.

    • O’Bryan
      You left such a high quality comment
      there’s not much I could add, except
      for a link to see some pictures.

      Brilliant:
      “When the rich stop buying and building beach front property, and the Chinese stop building on coral atolls and due to SLR, then we should worry about SLR. Until then, it’s just propaganda for the ignorant masses”.
      .
      .
      .
      Some pictures of the construction
      on the Maldives will make everyone
      wonder why so much capital is pouring
      into an area that was “supposed to be”
      the first victim of global warming / rising seas !

      https://www.dreamingofmaldives.com/banner/header-banner/banner-top-10-best-maldives-hotels-2017.jpg

    • Well the rich couldnt care, could look at it like buying a new pair of shoes to use for a couple of years, HOWEVER if they REALLY were concerned, people like Leo D, who endorses Global Warming, he would not have a 485 foot yacht. Of course, athelete’s also endorse products that they dont use/dont believe in..

    • Joel, not only sand. As I recall, there were some brilliant and patriotic citizens from the Philippines selling landfill to the Chinese that was shipped from the port of Cagayan de Oro.

  3. Excellent review, Rud. I think I will go play golf, and I won’t look over my shoulder to see if the ocean is coming. Have a great day.

    • Ron, you can just do what I do while golfing by the sea.

      I usually sacrifice one or two golf balls to the ocean to placate the angry gods of sea level rise.

      • Save your balls (pardon the expression) my slice (truly a thing to behold) has sacrificed more balls to the Gods of sea level rise than anyone on the planet!

        Not good coming from the West coast of Scotland where there are lots of Links courses.

        I have quit the game.

        [The mods recommend shooting golf balls … with a mortar and high explosives. .mod]

        • HotScot, I have known your slice pain. Two ‘simple’ possible Florida fixes.
          First, change your club grip from weak to stong. Getting slightly oversized grips helped me enormously.
          Sexond, change your pressing stance. (My significant other was formerly married to a golf pro). Check (stiffen) the right leg/knee. Initiate the downswing with hands, not legs . Amazing how those two fixes work.

    • Yes, an excellent review; many thanks.

      However the illustrations are really hard to see…is there any way to make them bigger/clearer? Maybe it’s just me using Firefox?

      • Alastair, the .docx submitted to ctm had them bigger as you requested. Plus, in that format they can be resized without severe lose of resolution as are .jpged from the referenced source papers. Ctm did some reformatting (Proof: I dont do image shadows, my ebook publisher wont allow it). Maybe a comment to ctm? Willis Eschenbach usually has bigger images, so maybe not a WordPress thing- but WE has direct WUWT posting priviledges, something I do NOT aspire to.

      • Alastair, “However the illustrations are really hard to see…is there any way to make them bigger/clearer?”

        – if you click AND HOLD on the picture you get a “searching for the picture in Google”.

        Try it.

        • Thanks Johann but it doesn’t seem to work for me…nothing comes up.

          I’m using Windows 10 with Firefox…maybe it works for Apple stuff? As it is I can’t even read the vertical text on the right of the second figure. I tried saving it to my computer (via a right click) and then opening it but it still comes up too small to read.

          Anyway, it’s not the end of the world…it’s still a good post by Rud.

  4. The WAIS area in antarctica sits over a rift which I understand is volcanically active with mount Eribus and Desolation Island in evidence. This probably accounts for the different behaviours between the East and the West areas of antarctica.
    Volcanic activity doesn’t seem to get much attention in these alarmist reports.
    There is also a rift running fairly close to the North pole under the arctic ice; but I cannot recall the name of it. I think it is a continuation of the Atlantic European tectonic interface; but again my memory is perhaps suspect. Can anyone confirm?

    Do wish they would get rid of this boring, boring, boring CO2 bug out of all these so called research papers and get back to real science.

    Thanks for an excellent appraisal. Much appreciated.

    • Would you be referring to the Gakkel ridge for the volcanic ridge near the Arctic? I came accross that several years ago. They say it doesn’t make any difference, but with my limited knowledge it seems that it has to have some impact.

    • Alastair, sole NAMED rift is “west Antarctica rift”. That’s an southern extension of the “Pacific ring of fire”.

      Best regards – Hans

  5. The empirical evidence for much higher sea levels during the Holocene Optimum in the Southern Hemisphere is abundant. Here are two examples of many. There is nothing new under the Sun.

    1. During the last 7000 years, southern African sea levels have fluctuated by ±3 m. Sea-level curves based on observational data for southern Africa indicate that Holocene highstands occurred at 6000 and again at 4000 cal years BP, followed by a lowstand from 3000 to 2000 cal years BP (South African Journal of Science http://www.sajs.co.za Volume 110 | Number 1/2 January/February 2014).

    2. The reported magnitude of the mid-Holocene highstand is variable along the Western Australian coastline, with estimates of þ2.0 to 3.5 m at Becher/Rockingham, Perth Basin (swash zone facies: Semeniuk, 1985; Searle andWoods, 1986; Searle et al., 1988) and at Rottnest Island (tubeworms: Baker et al., 2001b, 2005), þ2.05 m at the Houtman Abrolhos Islands (coral pavements: Collins et al., 2006), and þ1.5 min Shark Bay (shell material: Logan et al., 1970).

    • Dr. Bob, thanks for the good examples.

      Climate Bleg – Does anyone have a link to a good overview paper of all of the global evidence supporting the mid-Holocene highstand? (My searches have mostly found discussions of local evidence that are behind a paywall.)

      Thanks, P.I.

        • Chris,

          Thanks for the help.

          I had mis-remembered the Thailand study as a Vietnam study. (Turns out, it is much harder to find a study with the wrong words in the search parameters!)

          Your link looks like a good resource, I will check out some of their other papers.

      • I just spent the day boating and snorkeling in Southern Thailand near the Phi Phi Islands. The evidence in the wave cut rock is abundantly clear throughout most of SE Asia for s sea level that was 1-2 meters higher with cut benches and notches carved into the base of almost all the limestone cliffs everywhere for a few thousand miles in any direction.

        The notched rock that is so prevalent everywhere is about 2-3 meters above the present ocean level. Present day hydraulic action by waves didn’t do this with a recent lower sea level, but by a higher sea level fairly recently which aligns with the Holecene Highstand. There is also older evidence of sea levels much higher in a few places that the limestone hasn’t eroded away yet. That is evidence of the Eemian sea level interglacial when the oceans were 6-7 meters or higher.

        Undoubtably, a lot of other geological activity has happened since then such as uplift or subduction, which would change the relative elevations to present day SL. But it is so clear, from the Philippines to Vietnam to Thailand that there was just a very recent higher sea level. There may be geological arguments that the ocean basin hadn’t adjusted for the changed gravitational Geoid and the isostatic adjustments of ocean floors and continents so maybe it wasn’t all just more water in the oceans, but the evidence is in plain sight for a recent higher ocean level.

  6. My daily search for sea level news turns up this one from just a few hours ago:

    California Coastal Commission to Recommend Eminent Domain to Combat Sea-Level Rise?

    The California Coastal Commission is proposing to buy or condemn threatened homes and relocate them or tear them down, which would thereafter free the coastline and preserve the beaches. And when the sea doesn’t rise the Green big wigs can have a nice dacha for themselves isn’t that ever so nice

    The news article claims as much as 6.5 feet of sea level rise over the next 80 years. They never run the numbers. That comes to 25 mm/year every starting right now.

    • Exactly. At least in my view, the “catastrophic sea level rise” alarmism is for three reasons:

      1) For the nomenklatura that don’t yet have beachfront property, it keeps the price for acquiring lower.

      2) For the nomenklatura that do have beachfront property, it depresses the taxable value.

      3) For either group of nomenklatura, it reduces the number of peasants that visit beach destinations (which have a harder time getting insurance), destroying the serenity with their deplorable habit of actually making use of the beaches.

      • Yes, this is my litmus test for those who claim a climate catastrophe is “imminent”, i.e., always next year. Maybe.

        As John “Instapundit” Reynolds says, I’ll believe there is a climate crisis when the people who are telling me there is a climate crisis ACT as if there is a climate crisis. And not a moment sooner.

        So when Al Gore, Leonardo di Caprio and David Suzuki, among many others, sell their ocean-front property THEN I may start to start to maybe prep. A bit.

        • Caligula Jones..
          …”So when Al Gore, Leonardo di Caprio and David Suzuki, among many others, sell their ocean-front property”… THEN we should be able to buy at 10c on the $ and build a nice Gopherwood Ark with the change just to be on the safe side.
          Cheers
          Mike

  7. Abetted by additional NASA PR and author interviews (Rignot of NASA JPL, “Already gone into irreversible retreat, past the point of no return”, 2014 MSM alarmist headlines were, well, alarming. Reuters reported worldwide: “West Antarctic Glaciers in irreversible thaw: rising seas” [xiv] CNN said: “Ice melt in part of Antarctica ‘appears unstoppable’, NASA says” [xv] MSM TV was worse. [xvi] The KS spotted Wired ‘journalism’ is simply a 2018 echo of this alarmism.

    It has been “irreversible” since the Last Glacial Maximum…

    The history of deglaciation of the West Antarctic Ice Sheet (WAIS) gives clues about its future. Southward grounding-line migration was dated past three locations in the Ross Sea Embayment. Results indicate that most recession occurred during the middle to late Holocene in the absence of substantial sea level or climate forcing. Current grounding-line retreat may reflect ongoing ice recession that has been under way since the early Holocene. If so, the WAIS could continue to retreat even in the absence of further external forcing…

    The collapse (retreat of the grounding line) began about 20,000 years ago. It is irreversible because “the WAIS could continue to retreat even in the absence of further external forcing” and there are no topographic obstacles to prevent it from flowing downhill into the ocean. It will remain “irreversible” until we start rolling into the next Quaternary glacial stage.

    One has to wonder why this paper didn’t merit panic-stricken headlines in 1999…

    Conway, H. et al, 1999. Past and Future Grounding-Line Retreat of the West Antarctic Ice Sheet. Science 8 October 1999: Vol. 286 no. 5438 pp. 280-283

    DOI: 10.1126/science.286.5438.280

    http://www.sciencemag.org/content/286/5438/280.abstract

  8. A concise article that will have the warm-mongering 97 percenters sticking their fingers in their ears while singing, “La, la, la.”

    • They can go and read Oreskes and Conway’s SciFi The collapse of Western Civilization and get alarmed all over again about how 90% of the WAIS breaks apart, between 2073 and 2093, to add five meters to world sea level.

    • AE, sort of simples. After 4 intense years of grad achool (Harvard JD/MBA joint program), now 42+ years of practice, mostly at ~60 hours/week.

  9. Rud has provided us with another exciting game of scientific Whack-A-Mole! These games will continue because the big money is in alarmism.

    Sadly, the 97 percenters will never see any of these rebuttals to the widely hyped alarm.

  10. “But for 1.2 meters of SLR, the entire catchment basin would have no ice at all.”

    However since bedrock is mostly below sea level (otherwise the WAIS couldn’t collapse) much of that ice has to be replaced by seawater and since glacier ice is less dense than seawater it takes 1.13 cubic meters of glacier ice to make 1 cubic meter of (cold) seawater. So a very large proportion of the ice will be needed to fill up the hole after itself. This is the reason even the maximum feasible WAIS collapse would only raise sea-level about 10 feet, less than half of the effect of a total melt of Greenland.

    By the way it is not quite true that ANDRILL excluded collapse since the Pliocene. It found evidence that the Ross ice shelf had at least retreated south of the drill site during the very warm MIS 31 interglacial about 1.07 million years ago, but apparently never since.

  11. According to the AAAS, (Science magazine)
    125,000 years ago, the temperature was warmer and the seas were 6-9 meters higher.
    And this was caused by?

  12. They recently commenced a survey with drones under the ice shelf of one of the glaciers a bit south of Thwaites that is supposedly melting. Haven’t heard anything on the results yet. Be interesting to read what they find.

  13. What about this recent news that the WAIS has collapsed before resulting in meters of SLR:

    https://www.sciencemag.org/news/2018/12/discovery-recent-antarctic-ice-sheet-collapse-raises-fears-new-global-flood

    Some 125,000 years ago, during the last brief warm period between ice ages, Earth was awash. Temperatures during this time, called the Eemian, were barely higher than in today’s greenhouse-warmed world. Yet proxy records show sea levels were 6 to 9 meters higher than they are today, drowning huge swaths of what is now dry land. …Scientists have now identified the source of all that water: a collapse of the West Antarctic Ice Sheet.

    Sorry, I don’t have a link to the article, it is not actually published yet.

    • It is likely a garbage paper, no differnt than Oleary’s earlier Australian west coast paper comprising proven academic misconduct—and for the same reason in the same places.
      see my ‘proof’ explanation essay “By Land or by Sea” in ebook Blowing Smoke, or the similar equivalent earlier guest post over at Climate Etc.
      (Several of the ebook essays were originally tested as Climate Etc guest posts, to get feedback from Judith and her denizens. She knew, and graciously wrote a foreword).

  14. WWUT has published a number of articles like this over the years. It would be very useful if a page of links in the form of a FAQ were added to WWUT, that linked a set of questions that all skeptics hear to WWUT articles that explain what is really happening.

    E.G.:

    Q: Will the major ice sheets in Greenland and Antarctica melt and cause sea levels to rise dramatically in the foreseeable future?

    A: There is very little chance of that happening. https://wattsupwiththat.com/2019/01/08/antarctica-and-alarming-sea-level-rise/

  15. PIG and Thwaites glaciers comprise only about 15% of the catchment basin area and less of its ice volume

    So, the obvious follow on question is “How much sea level rise is possible if the PIG and Thwaites portions of the Embayment catchment basin were to completely melt?”

    Obviously, it is silly to think these area’s could completely melt without Antarctica moving away from the south poll. But it is a question of boundary limit.

  16. Impact crater 19 miles wide found beneath Greenland glacier
    The enormous bowl-shaped dent appears to be the result of a mile-wide iron meteorite slamming into the island at a speed of 12 miles per second as recently as 12,000 years ago.
    The impact of the 10bn-tonne space rock would have unleashed 47m times the energy of the Little Boy nuclear bomb dropped on Hiroshima in 1945. It would have melted vast amounts of ice, sending freshwater rushing into the oceans, and blasted rocky debris high into the atmosphere.

    https://www.theguardian.com/science/2018/nov/14/impact-crater-19-miles-wide-found-beneath-greenland-glacier

  17. The ‘latest’ data show that the glaciers emptying into the Amundsen embayment are no longer accelerating.
    In fact the large Pine Island glacier is decelerating. See reference [xii] figure 4. What is a bit strange to me is that no new data had been published since 2014. Maybe the slowing of discharge is worse than expected.

    • Does this mean that Pine Island is again gaining speed? Or is “break-up” what glaciers do normally when they reach the sea?

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