Study asks: How stable is the West Antarctic Ice Sheet? Then says doom ahead.

Exceeding critical temperature limits in the Southern Ocean may cause the collapse of ice sheets and a sharp rise in sea levels



Future warming of the Southern Ocean caused by rising greenhouse gas concentrations in the atmosphere may severely disrupt the stability of the West Antarctic Ice Sheet. The result would be a rise in the global sea level by several metres. A collapse of the West Antarctic Ice Sheet may have occurred during the last interglacial period 125,000 years ago, a period when the polar surface temperature was around two degrees Celsius higher than today. This is the result of a series of model simulations which the researchers of the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) have published online in the journalGeophysical Research Letters.

The Antarctic and Greenland are covered by ice sheets, which together store more than two thirds of the world’s freshwater. As temperatures rise, ice masses melt; in consequence the global sea level rises and threatens the coastal regions. According to scientific findings, the Antarctic already today contributes to the annual sea level rise with 0.4 millimetres. However, the most recent world climate assessment report (IPCC 2013) pointed out that the development of the ice masses in the Antarctic is not yet sufficiently understood. Climate modellers of the Alfred Wegener Institute have therefore analysed the changes to the Antarctic Ice Sheet in the last interglacial period and applied their findings to future projections.

“Both, for the last interglacial period around 125,000 years ago and for the future our study identifies critical temperature limits in the Southern Ocean: If the ocean temperature rises by more than two degrees Celsius compared with today, the marine-based West Antarctic Ice Sheet will be irreversibly lost. This will then lead to a significant Antarctic contribution to the sea level rise of some three to five metres”, explains AWI climate scientist Johannes Sutter. This rise, however, will only occur if climate change continues as it has up to now. The researchers make these assessments based on model simulations.

“Given a business-as-usual scenario of global warming, the collapse of the West Antarctic could proceed very rapidly and the West Antarctic ice masses could completely disappear within the next 1,000 years”, says Johannes Sutter, the study’s main author, who has just completed his doctoral thesis on this topic. “The core objective of the study is to understand the dynamics of the West Antarctic during the last interglacial period and the associated rise in sea level. It has been a mystery until now how the estimated sea level rise of a total of about seven metres came about during the last interglacial period. Because other studies indicate that Greenland alone could not have done it”, Prof Gerrit Lohmann, the head of the research project, adds.

The new findings on the dynamics of the ice sheet allow conclusions to be drawn about how the ice sheet might behave in the wake of global warming. According to model calculations, the ice masses shrink in two phases. The first phase leads to a retreat of the ice shelves, ice masses that float on the ocean in the coastal area of the Antarctic stabilising the major glacier systems of the West Antarctic. If the ice shelves are lost, the ice masses and glaciers of the hinterland accelerate and the ice flow into the oceans increases. As a result, the sea level rises, the grounding line retreats, leading to a further floatation of the grounded ice masses with a progressing acceleration and retreat of the glaciers. These will achieve a stable intermediate state only once – put simply – a mountain ridge under the ice temporarily slows down the retreat of the ice masses.

If the ocean temperature continues to rise or if the grounding line of the inland ice reaches a steeply ascending subsurface, then the glaciers will continue to retreat even if the initial stable intermediate state has been reached. Ultimately, this leads to a complete collapse of the West Antarctic Ice Sheet. “Two maxima are also apparent in the reconstructions of the sea level rise in the last interglacial period. The behaviour of the West Antarctic in our newly developed model could be the mechanistic explanation for this”, says a delighted Johannes Sutter.

The climate scientists used two models in their study. A climate model that includes various Earth system components such as atmosphere, oceans and vegetation, and a dynamic ice sheet model that includes all basic components of an ice sheet (floating ice shelves, grounded inland ice on the subsurface, the movement of the grounding line). Two different simulations were used with the climate model for the last interglacial period to feed the ice sheet model with all the necessary climate information.

“One reason for the considerable uncertainties when it comes to projecting the development of the sea level is that the ice sheet does not simply rest on the continent in steady state, but rather can be subject to dramatic changes”, according to the AWI climate scientists, emphasising the challenges involved in making good estimates. “Some feedback processes, such as between the ice shelf areas and the ocean underneath, have not yet been incorporated into the climate models. We at the AWI as well as other international groups are working on this full steam.” Improving our understanding of the systematic interaction between climate and ice sheets is crucial in order to answer one of the central questions of current climate research and for future generations: How steeply and, above all, how quickly can the sea level rise in the future?


Original paper:

Johannes Sutter, Paul Gierz, Klaus Grosfeld, Malte Thoma, Gerrit Lohmann: Ocean temperature thresholds for Last Interglacial West Antarctic Ice Sheet collapse. Geophysical Research Letters 2016. DOI: 10.1002/2016GL067818

149 thoughts on “Study asks: How stable is the West Antarctic Ice Sheet? Then says doom ahead.

  1. “says Johannes Sutter, the study’s main author, who has just completed his doctoral thesis on this topic.”
    What? Send in the “A” team to do the research if we are all going to die. I don’t want someone just out of college. But at least he has been well educated on how to make money in the climate game.

    • …then comes the biggest word in climate science: “may”. Everything is an educated guess with them, tantamount to using the SWAG system.

      • ” Everything is an educated guess”
        I assume that in climate “science” the term “educated” is a technical term and has a different meaning to what it does in common parlance.

      • Don’t forget “Could” and “Might” and “Possibly”. be something to do with active Volcano’s under the ice and nothing to do with the climate. hmmm!

    • Well he might actually be correct that warming of the Southern Oceans might cause the collapse of the Antarctic ice sheets. Just think of all that extra weight of snow deposits on the Antarctic continent, with catastrophically increased evaporation from warmed southern oceans; what a collapse that might trigger.
      But there’s a snag there in his thesis. Rising greenhouse gases; we’re talking CO2 here and that pesky methane, likely might warm the atmosphere, but thermodynamics would seem to dictate that that can’t transfer heat to the oceans; most likely the verse vicea would happen.
      Warming of the oceans is done; when or if it is done, by the radiant energy from the sun, that gets absorbed in those deep oceans. And increased GHGs especially H2O, tends to reduce the amount of solar energy that even gets down to those ocean surfaces.
      I guess this grad student should consider applying for his post doc fellowship right away, as his thesis doesn’t seem to have any great industrial market appeal, or value, so he could be heading into the unemployable class.

      • george, I don’t think their model makes any sense, but your claim that the atmosphere does not heat the oceans misses the entire mechanism on how the atmospheric greenhouse effect works. The atmosphere is not directly heating the ocean, but does still result in it warming due to decreasing the net radiation up. The effect of absorbed back radiation acts like a partial radiation resistance, and this radiation resistance is one component (along with convection, evapotransporation, the increase in average location of radiation to space and the lapse rate) of the warming. The problem with their models are many, including an assumed CO2 sensitivity and a thousand year linear slow increase in temperature, which have no basis at all.

      • They said, “… the marine-based West Antarctic Ice Sheet will be irreversibly lost”. Irreversibly … absolutely never to return.
        It might take 1,000 years to go away, but it would be IRREVERSIBLY lost.
        So no, they cannot in any way be assumed to be correct in their absolutist guess..

      • I’ve debunked dozens of these studies. These environmental studies students never incorporate real physics into their models, therefore the cooling effect of melting the ice almost never figures in their models. They as a consequence have NO IDEA how much energy it takes to melt 2 million cubic km of ice.

      • Leonard Weinstein: “…but does still result in it warming due to decreasing the net radiation up…”
        ??? From a miniscule increase in lapse rate? In the few atmospheric IR windows not fully saturated with water vapor?
        Given the speed of light, just how does a miniscule increase in apse rate become “decreasing net radiation”?

      • George, how do you expect them to get all that higher thermo stuff when they cannot even get this right -” As temperatures rise, ice masses melt; in consequence the global sea level rises and threatens the coastal regions. ”
        No, ice does not melt until the temperature is over 0 C or 32 F. Even sublimation is more dependent – Sublimation occurs more readily when certain weather conditions are present, such as low relative humidity and dry winds. Sublimation also occurs more at higher altitudes, where the air pressure is less than at lower altitudes. Energy, such as strong sunlight, is also needed.
        Temperature still not mentioned.
        Bobl – energy per KM^3 –
        4.13 x 10^17 joules / KM^3. What does that number represent? That is the energy it takes to convert one cubic kilometer of continental ice from -30 oC to water at 4 oC

      • “””””….. but thermodynamics would seem to dictate that that can’t transfer heat to the oceans; ……”””””
        “”””””….. but your claim that the atmosphere does not heat the oceans misses the entire mechanism on how the atmospheric greenhouse effect works. …..””””
        As you can see Leonard, I made no such claim that you assert.
        The second law (of thermodynamics) prohibits a net transfer of ” HEAT ENERGY(noun) ” from a colder body (the atmosphere) to a warmer body (the non gaseous surface).
        Clearly conduction, convection, evaporation, are transporting HEAT (thermal mechanical energy) from the solar heated surface to the cooler upper reaches of the atmosphere, and thermal radiant energy from the surface is also contributing that via the molecular resonances of green house gases, such as CO2, O3, and H2O, which comprise a small part of the atmosphere.
        A net upward transport of HEAT, and additional warming energy from GHG radiation absorption spectra of GHGs.
        Those heated atmosphere components are elevated by convection and removed from contact with the surface, and can’t convey net HEAT energy downward to the hotter surface.
        Any radiant emissions (EM radiation) from those upper colder atmospheric gases, however generated, can of course partially propagate to the surface (< 50%) since the upward colder less dense atmosphere favors escape, whereas the downward warmer denser air favors recapture by atmospheric GHGs. So downward LWIR radiant energy from the upper colder atmosphere can certainly reach the surface and be partially absorbed, but more than 70% of that reaches a water surface, and at wavelengths that are strongly absorbed in the top few microns of that surface where they largely just result in increased evaporation.
        I agree downward radiation can reach the surface, but a net downward transport of HEAT ENERGY (noun) is not possible.

    • “The researchers make these assessments based on model simulations.”
      Did they mean assumptions? As in ” ass – u – me “

  2. So, in summary…It’s worse than the other models say it is, so send us more money now !!! Only we can save you ( IF you give us more money ) !!

  3. A thousand years out? When history shows a very great tendency towards cycles of warm and cold? What mechanism are they presupposing to eliminate that tendency? OMG CO2!

  4. “Given a business-as-usual scenario of global warming, the collapse of the West Antarctic could proceed very rapidly and the West Antarctic ice masses could completely disappear within the next 1,000 years”, says Johannes Sutter.
    That’s great Johannes but this, ah, global warming you refer to – would you, um, have any evidence in support of that at all? Also it would be nice if there was some evidence that any climate modelling has enjoyed any level of skill to speak of before we all get too terrified by these new modeled results. Oh, and it appears that Antarctica is in fact seeing increasing ice mass and sea ice extent but I suppose that is irrelevant to the model.
    “We at the AWI as well as other international groups are working on this full steam”
    How reassuring!

    • Oh…and did we ever say the science was settled…no, not us!! We think we need to spend much more time postponing the understanding….refuting the consensus….no….confirming the consensus…no, wait…there is no consensus!!!!! CSIRO? What is that????

    • Eh, back in 1965 the leading Warmists of the day predicted sea levels could be 10 feet higher by the year 2000 with full collapse of the Antarctic and Greenland ice by 2200.
      I guess the world has received an 800 year reprieve.

      • Mercer, John H. “West Antarctic ice sheet and CO 2 greenhouse effect- A threat of disaster.” Nature 271.5643 (1978): 321-325.
        700 citations!

    • Full Steam? Isn’t that a deadly greenhouse gas too? You think he would choose his words more carefully.

  5. How the hell does this drivel-laden collection of conjectures pass critical review? Not only is it incomprehensible, it is based on a sort of GIGO-squared guess from the last interglacial. One that was two degrees warmer without a single coal-fired power plant in sight. Astounding….all the more so because robots like Obama quote this shytte as fact.

    • “How the hell does this drivel-laden collection of conjectures pass critical review?”
      A thoroughly brainwashed and sympathetic press that is stuck on a narrative that has been fed to them since grade school is how all of this drivel passes critical review. The AGW propaganda (among other things) infiltrated our children’s classrooms and minds while none of us were paying attention.

  6. Even if this is correct, a problem that may occur in a 1000 years time should be prioritised accordingly.
    We didn’t expect William the Conqueror to deal with the Luftwaffe.
    We shouldn’t try and use our technological resources to deal with this problem.
    We have problems and responsibilities of our own.

      • I’d say that is even better than saying: ” The Gattling gun is not backwards compatible with the long bow ! ”
        Yeah, a gold star for MC.

      • therealnormanrogers,
        The Courtney family traces our heritage in these isles only as far back as the Conquest.
        My loyalty to the defence of the White Cliffs can only, reasonably, date back to then.

    • >”We didn’t expect William the Conqueror to deal with the Luftwaffe.”
      That is the best line I have read in a long time. Kudos!

    • Beautifully put! This point is one I would love to see out there and in use a lot because it sums up the issues so perfectly. How pitiful our current attempts must be when put in proper perspective! I’m placing this argument at the top of my list. Thank you and +1000 on your comment.

      • What if we didn’t cause ‘it?’ Where is the moral duty to ameliorate something that will not happen, so ‘it’ was not caused by us? Amelioration, as you call it, is extremely damaging to real lives … based on science that seems to be not at all well understood.

      • Dan, we have many moral duties but we do not have infinite resources.
        For the sake of argument let’s assume that we are causing this problem.
        Can you imagine the disgust with which our morality will be judged if we prioritised preventing the WAIS form collapsing in 1000 years time over providing clean water for the poor today.]
        “We could fix that problem for nothing with our freezing satellites we had to get half a millennium ago. Of course, you primitives in the 21st century couldn’t have known we would have that. But you still could have spent your resources on problems you did know about”.
        AGW is like eugenics and slavery.
        Morally justified in the minds of the adherents.
        But Indefensible through the lens of history.

      • AGW is like eugenics and slavery.
        Morally justified in the minds of the adherents.
        But Indefensible through the lens of history.

        Wow. That is a profoundly stupid statement MCourtney. You have become your father.

        • Dan

          Wow. That is a profoundly stupid statement MCourtney.

          A statement, no doubt. Now, why do “you” think it is a stupid statement, and why should “I” believe your opinion is correct?

  7. Tell you what authors, the West Antarctic ice sheet is very considerably more stable than your jobs when even idiots like Camoron, Obama and similar work out how you’ve been hoodwinking them with such garbage non-science for the last generation.

  8. So, is the claim now there will be no exit from our current interglacial back to a full ice age again?
    When they prove there is no ice age coming I’ll start to worry about CAGW.

    • Feature not a bug. Real glaciation would be a much bigger problem than rising oceans. 15,000 years ago the place I am sitting at 40°N and 245m above msl, was covered by about 1500 m of ice.

    • This is a link to a free access article in the Chicago Tribune that has more detail.
      last section places this in context.
      “Dr. George Denton, another University of Main glacial expert, recently has found evidence that the Ross shelf is rapidly disintegrating. …at one time the shelf extended all the way across the Ross Sea…and…was so thick that it rested on the sea floor.
      Within the last 6,000 years, the shelf has shrunk and no longer rests on the sea bottom: it is now floating….The dome of the shelf was at least 1,300 feet higher about 30,000 years ago.”
      So the context is that the West Antarctic ice has been decreasing for 30,000 years. Last time I checked, there was no evidence of SUVs that long ago.

  9. “… during the last interglacial period 125,000 years ago, a period when the polar surface temperature was around two degrees Celsius higher than today…:
    Oh those poor souls, laying waste to Marcott 2013 (yet again.)

    • Are you saying that 125,000 years ago, the Antarctic highlands, only got down to -92 deg. C, instead of the -94 deg. C that they get down to today ??

      • Yes.
        But it gets even worse… applying the climate science logic of ocean “acidification”, the highland ice would have been more liquid at -92 degrees than at -94 degrees and that’s where it’s heading again!

  10. Ocean warming from increased CO2………mechanism and measurements , please …..
    and model ” data ” does not mean shineola …

  11. It has been a mystery until now how the estimated sea level rise of a total of about seven metres came about during the last interglacial period.

    If it happened naturally during the previous interglacial, I see no reason why it could not happen even naturally during this interglacial. I think the best approach is to prepare to adapt.
    The scientists in question talk about ‘collapse’. While in the geological sense, collapse might well describe something that lasts a millennium, linking this to AGW making up a CAGW scenario is kind of bullshit.
    And no, I’m not a de-nier. The WAIS really ‘could’ collapse during the next 1000 years. And human GHGs ‘could’ play a role. But what comes to conclusions drawn by random green readers, GHGs are not the central problem, the central problem is we don’t know even how the interglacials would work without humans around. These scientists, I hope, have done good work in revealing the uncertainties around. It is just that coming to publicity means staying on message.

    • “f it happened naturally during the previous interglacial”
      It probably didn’t. That “6-9 meters” figure is a factoid, i e something repeated so often that everybody thinks it is an established fact, while there is actually little real evidence for it and a great deal against it.

      • There are a fair number of stranded, last interglacial, reefs on what are thought to be “stable platforms”, e.g. Bahamas, Florida, Seychelles that are 6 to 8 meters above current sea level. It’s possible that there is no such thing as a stable platform, but it’s also possible that they exist and sea level really was 20ft or more above current the last time the planet was warm.
        It’d probably be a good idea to allow for considerable sea level rise in the next ten centuries or so. Probably doesn’t matter where you put parking lots and marinas, but transportation tunnels, bridge approaches etc, might best be well up above current sea level, or at least hardenable if it turns out there is a problem.

  12. To be fair, Marcott only covered the past 10,000 years, but the paper is used to prop up the “warmest year ever recorded” meme, which becomes ridiculous in light of evidence that the earth has undergone many eras warmer than present

    • @ mods: this comment was supposed to be attached to my comment at 6:51am. Not sure why it didn’t-
      [We’re not sure either. Sometimes WordPress does inexplicable things. -mod]

    • Ah, but the terrible heat is hiding deep in the ocean and undermining the ice!
      Yes, seriously. This is actually the official “party line”.

    • My fellow Paul: Wait a minute, that chart isn’t even based on a climate model! Typical den*alist tactic, using data before NOAA has taken it to the “adjustment” room in the basement. Since we KNOW it’s warming, (it’s physics) showing this obviously biased data should get you thrown in jail (or at least to the “attitude adjustment” room. Bartender, another sarc. please.

  13. I say we send these chaps to live in the center of Antarctica since it is going to melt. Give them all fishing poles so they can go catch their dinners there. They are NOT allowed to eat any Emperor Penguins!

  14. The weirdest thing about this constant yammering about imminent WAIS (West Antarctic Ice Sheet) collapse is that it is based on two premises that are never questioned:
    1. The WAIS collapsed during the last interglacial.
    2. Sea-level during the last interglacial was 6-9 meters higher than now.
    However there is no real evidence at all for 1) and very little for 2).
    We know for certain that West Antarctica did not deglaciate completely during the last interglacial since there is conclusive evidence for very extensive glaciation at that time in at least three widely separated areas (Marie Byrd Land, Ohio Range and Ellsworth Range). There is on the other hand not a shred of evidence that West Antarctica was ice free during the last interglacial. On the contrary oxygen isotope data from last interglacial ice om Mt Moulton indicates temperatures only marginally warmer than today and the ANDRILL-1B core indicates that the shelf ice in the Ross Sea was not appreciably smaller than today. Also there is not a trace of young marine deposits anywhere inland in West (or East) Antarctica.

    • Exactly!! The Southern Ocean might need to stop cooling first – you would think – in any rational world. And two degrees in 125,000 years; for f%ck sake, what weren’t they thinking!
      There is some ’trixy’ wording though:

      A collapse of the West Antarctic Ice Sheet may have occurred during the last interglacial period 125,000 years ago, a period when the polar SURFACE temperature was around two degrees Celsius higher than today.If the OCEAN temperature rises by more than two degrees Celsius compared with today, the marine-based West Antarctic Ice Sheet will be irreversibly lost.

  15. If the ocean temperature rises by more than two degrees Celsius compared with today, the marine-based West Antarctic Ice Sheet will be irreversibly lost.
    Since 1907, the southern oceans have warmed by ~0.8 °C. So, we have 275 years to prepare for the Gorebotic version of a Noachian Deluge.
    Oddly enough, they were warming more rapidly before 1940 when atmospheric CO2 was “safely” below 350 ppm.

  16. Yet another climate model geofantasy! Did the authors bother to check their results against reality? Did the West Antarctic ice sheet collapse during the last interglacial (the basis for their model)? There is no evidence that the West Antarctic ice sheet has ever collapsed, even when temperatures there were higher than at present..
    About a year ago, I looked into the situation and found that most of the West Antarctic ice sheet is thicker than the depth of its base below sea level, so it isn’t going to float and collapse suddenly, Geothermal heat is unusually high beneath the small part of the ice sheet that makes up the two small outlet glaciers cited as ‘collapsing’ (they aren’t), so it looks like that’s the reason for small increases in local calving of the two outlet glaciers. It certainly doesn’t have anything to do with global warming–satellite measurements show no warming in Antarctica in 37 years and surface temperature measurements at the South Pole and Vostock show no increase in temperature since 1957. As Paul Homewood points out in his post above, Southern Ocean SST has been declining for the past 20 years, not warming.
    Consider what happened at the end of the Last Ice Age when gigantic ice sheets coving much of the northern latitudes melted under temperatures rising at rates of ~20 F per century. Sea level rose at rates of about a meter per century. The West Antarctic Ice Sheet makes up less than 10% of Antarctic ice, a puny amount relative to the huge ice sheets that melted suddenly at the end of the Pleistocene.
    So much for yet another failed model study.

      • Well all of the GCMs don’t model ANY real rotating planet, that actually is bathed continuously on its sunlit side by a TSI beam at an annual average rate of 1362-6 W/m^2, instead of a flat planet with a stationary sun above, that is at an annual average distance of 186 million miles, so it only generates a 341 W/m^2 average annual TSI, which isn’t enough to bring a BB equivalent temperature above 5 deg. C with a 0% planet albedo, or above 255 K with a 30% planet albedo, such as earth has.
        The earth’s actual sunlit side insolation, with a 30% albedo, is heading for a BB equilibrium Temperature of 360 K at that sunlit region during the daylight hours.
        Lucky for us, night falls, before it gets there.

    • Vostok has warmed at 0.16 deg C / decade since 1957, according to the Russians who run the place.

  17. Future warming of the Southern Ocean caused by rising greenhouse gas concentrations in the atmosphere may severely disrupt the stability of the West Antarctic Ice Sheet.
    And I thought the local sub-aerial volcanoes had something to do with it.

  18. It is correct that during the Eemian interglacial, sea level reached 6-7 meters higher than at present. This took about 3000 years, so was meltwater not ice sheet collapse. See Kopp 2009 in Nature for details. The main paper concluding otherwise, OLeary 2013 in Nature Geoscience, comprises a clear cut case of academic misconduct, specifically misrepresenting data. Essay By Land or by Sea. So these model results are BS.

    • If you believe AR1 thru AR5, and really, I see no reason not to, thermal expansion also plays a substantial role in 20th century sea level rise. That could easily continue even with the Sea Surface Temperature not changing much at all if surface warmth slowly works its way downward. It appears to me that the IPCC sea level folks still don’t have their sea level rise budget completely worked out. Neither do they seem to anxious to address the still substantial mismatch between tidal gauge and satellite measurements. Or maybe they do address it in AR5 and I missed it. AR5 is written in a rather opaque style.

      • SLR has two components: icesheet water, and thermosteric rise. The so called closure problem is that observed SLR dos not equal estimates of the two components. Depending on who does the calculation, off by 1/3 to 1/2. Essay PseudoPrecision goes into details.

  19. With the mean annual temperature of the interior of Antarctica at −57 °C (−70.6 °F), I’m curious where all the melting is expected to come from. This temperature would have to increase by over 55°C to melt. Even the most aggressive models don’t show this level of warming.

    • They didn’t claim it melts there, they said it collapses, which refers to ice flowing down to sea, where it then can melt. If Eemian interglacial has SL 7m higher, I see absolutely no reason why it would not happen again. But it takes more than centuries.
      And they might be wrong. It could be it won’t happen. We don’t have a full picture of this yet.

      a period when the polar surface temperature was around two degrees Celsius higher than today

      Look they say interglacial could be even 2K warmer naturally. And they didn’t take Zwally paper into account. We are still far from an unprecedented interglacial.

      • If the msl rises by 7m we will have to move to higher ground or build higher sea walls. OTOH, if it is over 1000 years, that means we will have to deal with a rise of 7 mm/yr. We ought to be able to do that at a slow walk. All structures that are now in place will be fully depreciated within 50 years so the loss of permanent capital due to ocean rises of about 350mm over that time period should be zero.

      Using this as a model…
      Warm air is less dense than cold air, so perhaps the warmer lighter air isn’t putting as much pressure on the volcanoes under the ice sheets, causing more glacial melting, causing more ice to slide into the sea.
      It makes as much sense as most of the arguments Warmists use to turn an upward trend of atmospheric CO2 into certain climate doom.

    • The melting is bottom up, and it’s always going on. What they’re suggesting is faster flow, with melting exceeding precipitation. Worst case: a thousand years to deal with what Long Beach had to deal with in 50. –AGF

  20. They do the typical Warmist trick of saying that 2 degrees of atmospheric warming (which would still not raise Antarctic temps above freezing) will result in 2 degrees of ocean warming

  21. We know that the modelled “business-as-usual” scenario drastically overstates the likely warming.
    Even assuming this projection is right this is a problem for my 25*great-(at least!)grandchildren.
    This likelihood is further into the future than William the Conqueror’s invasion of Enlgland is in the past!
    When are these fools going to develop a sense of proportion?

  22. I’m confused. Doesn’t “marine-based” mean ice that is already floating in the ocean? Melting of marine based ice does not raise sea level.

    • Rick, the two great WAIS ice shelves, Ronne and Ross, have a floating shelf portion, but the majority is grounded. The grounded portions could raise sea level if they shrank. But they aren’t.

      • Yes, but I don’t see where sea surface temperature rise (even if it actually happens) would do more than melt some of the sea ice. Since the year round temperature in Antarctica is well more than a couple degrees C below the freezing point, what causes the land ice to melt? Or is it all being held in place by the sea ice and will suddenly (over a period of 1000 yrs?) slide off into the Southern Ocean? Seems like pure speculation to me.

      • The ice melts iff it flows to the sea. Rising sea level will help that flow to some extent, but I would not bet on that happening too easily.

    • Well it actually lowers sea level, because most of that floating ice and its surface area is underneath the water, so the latent heat required to unfreeze all that ice, must come from the ocean water it is floating in, and not from the atmosphere. Melting one gram of floating ice can cool 80 grams of water by one deg. C, and since salt water has increasing density all the way down to its freezing point (no Temperature of maximum density) than the cooled ocean waters must shrink.
      Of course it might also cool 800 grams of sea water by just 0.1 deg. C or it might cool 10 grams of sea water by 8 deg. C
      This is really a one dimensional problem, if it is happening over a large surface area, so if the longitudinal coefficient of expansion of sea water is constant over that Temperature region, then the amount of sea level drop is quite independent of the distribution of that latent heat sourcing.
      Cooling 10 times as thick a water column by one tenth of the Temperature delta produces exactly the same loss in sea level.
      So melting sea floating ice causes the sea surface level to fall.
      When I pointed this simple incontrovertible fact out, in a letter to ” Physics Today, ” a prominent AGW warmista responded that I was all wet (in effect), and my conjecture was nonsense.
      I wrote that letter in response to a book review by a chap named (I think) Morrison, who I also believe is now deceased. He was reviewing a book; ” The Discovery of Global Warming. ” by an author named Spencer Weart.
      It was Weart who pooh poohed my assertion that the sea level must fall, when floating sea ice melts.
      It so happens, that he recently, in the same journal Physics Today, authored a rather lame response to another letter writer, who had also commented on another work by Weart. I think it is either the Jan or Feb 2016 issue of PT.

      • George, hasn’t that ice also already displaced its volume in the ocean and, and being 10% less dense than water, it would shrink the volume of the ocean, too.

      • Gary, I get where you are going, but I think maybe that isn’t so.
        Let’s put any “cooling” of the ocean water aside for the moment, and just consider the floating ice.
        9/10 or 10/11 of the ice is below the water. The remainder is up above the surface.
        BUT …. 100% of the water in that floating ice just fits perfectly into the volume of the ice below the surface, once it liquefies.
        So the ” hole ” in the ocean is just big enough to take ALL of the water in the floating ice.
        That is simply the Archimedes principle.
        But it is the cooling of a huge volume of sea water to supply the latent heat of melting the ice (80 calories per gram) that shrinks the ocean water and lowers the sea level due to the fact that sea water shrinks (increases in density) as the Temperature is lowered, all the way down to its freezing point (for sea water with even much lower salinity than ordinary ocean water.
        So it is not like FRESH WATER that has a maximum density at 4 deg. C

  23. I like Anthony’s quip “modeled certainty department”. That is exactly how it is. And there will be kudos and prizes to whoever can programme the supercomputers so that they come out with the desired answers. That is a sad state of affairs for a science foundation – and how ironic that this one is The Alfred Wegener Institute. He was ridiculed all his life for holding on to his sensible theory opposing the consensus of all scientific “experts”.

  24. “…during the last interglacial period 125,000 years ago, a period when the polar surface temperature was around two degrees Celsius higher than today…”
    Didn’t the worlds top scientists just tell us that 2015 was warmer than any time in the past 2 million years?
    You guys need to get together and make sure your stories aren’t contradicting each other.

  25. Oh my, three to five meters in as little as a thousand years, assuming of course the interglacial doesn’t end before that. Isn’t that as fast as 3 to 5 mm per year sea level rise? Armed with this fearful prophecy I’ll be running out to buy some new waders.

  26. Sutter’s study’s conclusion is predicated on the incorrect assumption that CO2 caused the recent warming and hence assumed the warming will continue (ignoring the observational fact the planet has not warmed for more than 18 years).
    The theoretic estimated surface warming, I repeat surface warming due to a doubling of atmospheric CO2 is almost completely offset by the reduction in the lapse rate that occurs due to increased convection. Convection (hot air rises which causes cold air to fall hence changing the lapse rate) is a physical fact not a theory. The reduction in the lapse rate reduces surface warming for a doubling of atmospheric from 1.2C to less than 0.3C (by a more than a factor of four).
    Hansen and his buddies ‘no feedback’ 1 dimensional CO2 forcing calculation that determined 3.7 watts/meter^2 increased warming due to a doubling of atmospheric CO2 assumed no change in the lapse rate and did the calculation for a dry atmosphere.
    As the planet is 70% covered with water there is a great deal of water vapor in the atmosphere. It is a physical fact not a theory that the absorption spectrums of water and CO2 overlap so there is almost no significant increase in atmospheric warming due to an increase in CO2 from current levels if the water vapor content of the atmosphere region in question is more than 10% of saturated.
    A 1986 peer reviewed paper noted the 1 dimensional feedback surface forcing for a doubling of atmospheric CO2 would be reduced by a factor of four, if the calculation was redone using a conservative back of the envelop minimum estimate of the water vapor (the calculations were purposely incorrect, as if the calculation was done correctly there is no CAGW there is no AGW CO2 problem), rather than assume ludicrously that the atmosphere is dry for the 1 dimensional calculations.
    The reduction in lapse rate and the reduction in the forcing due to the fact that there is water vapor in the atmosphere and the absorption of water vapor and CO2 overlap reduces the surface warming without ‘feedbacks’ for a doubling of atmospheric CO2 by a factor of 16 to around 0.075C, less than 0.1C. As surface warming less than 0.1C is so small, the without feedbacks warming for a doubling of atmospheric CO2 is the same as the with feedbacks warming.
    The general circulation models (GCM) which some refer to as 3 dimensional modeling, have a 100 parameters in them which can be subjectively adjusted. The GCMs can hence be adjusted to provide any warming or cooling that is desirable by the model.
    In the pale record there is a massive increase in dust deposited on the Greenland ice sheet that coincides with the cyclic abrupt cooling events. The origin of the dust is the Mongolian desert which requires that there to be a massive increase in the speed of the jet stream, to enable the dust to be transported from the Mongolian desert to the Greenland ice sheet. Note the increase in dust on the Greenland ice sheet has happened again and again. The paleo climate researchers use the change in ice core conductivity due to the increase dust to find the abrupt climate change events.
    There has been suddenly an unexplained increase in the jet stream speed (See warmists news release Yahoo for example). Of course the cult of CAGW nincompoops asserted that the increase in jet stream speed is due to global warming which is ludicrous (why did the jet stream suddenly increase now, what is the mechanism). The increase in jet stream speed is due to the solar cycle changes and is the reason (in addition to an increase in cloud cover 40 to 60 degree latitude ) why the North Atlantic ocean was in sections in the region 40 to 60 degrees latitude 10C cooling than present.

    Timing of abrupt climate change: A precise clock by Stefan Rahmstorf
    Many paleoclimatic data reveal a approx. 1,500 year cyclicity of unknown origin. A crucial question is how stable and regular this cycle is. An analysis of the GISP2 ice core record from Greenland reveals that abrupt climate events appear to be paced by a 1,470-year cycle with a period that is probably stable to within a few percent; with 95% confidence the period is maintained to better than 12% over at least 23 cycles. This highly precise clock points to an origin outside the Earth system (William: Solar magnetic cycle changes cause warming and cooling); oscillatory modes within the Earth system can be expected to be far more irregular in period.

    Davis and Taylor: “Does the current global warming signal reflect a natural cycle”
    …We found 342 natural warming events (NWEs) corresponding to this definition, distributed over the past 250,000 years …. …. The 342 NWEs contained in the Vostok ice core record are divided into low-rate warming events (LRWEs; < 0.74oC/century) and high rate warming events (HRWEs; ≥ 0.74oC /century) (Figure). … …. "Recent Antarctic Peninsula warming relative to Holocene climate and ice – shelf history" and authored by Robert Mulvaney and colleagues of the British Antarctic Survey ( Nature , 2012, doi:10.1038/nature11391),reports two recent natural warming cycles, one around 1500 AD and another around 400 AD, measured from isotope (deuterium) concentrations in ice cores bored adjacent to recent breaks in the ice shelf in northeast Antarctica. ….

    In the 1990’s paleoclimatologists’ discovered evidence in the Greenland ice sheet core data that the periodic 200yr, 500yr, 1500yr, 8000yr, etc. climate changes (up to 20C drop in the Greenland ice sheet temperature) were rapid not gradual events. For example, the Greenland ice core data shows that the Younger Dryas cooling event occurred in a 5 year period (Younger Dryas is the name for a climate change from the current interglacial Holocene, warm period back to the Wisconsin glacial, cold period that occurred 12,800 yrs ago).
    The Greenland ice core finding was not expected (the old consensus belief was that climate changes were gradual) and many at first stated the planet’s climate could not possibly change that rapidly. (The doubter’s suggested that the ice core data was flawed.) A second Greenland ice core was drilled. The second set of ice core data corroborated that the changes were very, very, rapid.
    As the planet resists rather than amplifies forcing changes the massive rapid temperature changes in the paleo record require a massive forcing function. It massive forcing function is solar cycle changes. The sun can from time to time be transformed into an angry beast.
    The planet is going to abruptly cool, due to the interruption to the solar cycle. The solar cycle is not slowing down, it has been interrupted. The increase jet stream speed has started. The cooling has started.
    The warm blob off of the US west coast is almost gone.

    • WA
      Very interesting about the Mongolian dust layers in Greenland ice and evidence for periodic rapid cooling. I was with you entirely up till the comment about a big change needing a big forcing. The climate system is not passive but driven by powerful internal nonlinear oscillations with a fractal signature (frequent small changes, log-infrequent log-big changes).
      Nonlinear oscillators can be externally periodically forced. The solar cycle and changes therefore is never strong enough to change climate by brute force. But it could easily by providing even weak periodic forcing, entrain it to regular large excursions following a solar pacing.

  27. I was under the impression most if not all the Antarctic ice sheet is afloat.
    Correct me if I’m wrong. This is a media phd, not science. lol

    • Your wrong. But large parts of the glacier are below sea level, so once water lifts the ice afloat, if can float away.

    • Most of WAIS is above sea level. There are grounded portions of Ross and Ronne ice shelves that are grounded below. Ronne is pinned by the substantial island that bifurcates it. Ross is pinned by numerous rocky seamounts. The ice can and does creep around these impediments. But muchb slower than a glacier would. The ice for both is renewed higher in the respective catchment basins. Zwally’s ice mass analysis suggests Ronne is gaining and Ross is roughly stable. WAIS ice mass loss is mainly PIG and Thwaites sea facing glaciers in the Amundsen Embayment. Details in essay Tipping Points.

  28. “The climate scientists used two models in their study. A climate model that includes various Earth system components such as atmosphere, oceans and vegetation, and a dynamic ice sheet model that includes all basic components of an ice sheet (floating ice shelves, grounded inland ice on the subsurface, the movement of the grounding line). ”
    Since climate models are almost all too warm(many are MUCH too warm)…….using incorrect assumptions about CO2, water vapor, the water cycle, clouds and so on, one has too ASSUME that they were wrong before they even started to apply their incorrect assumptions.

  29. Saying you are assuming “a business as usual” future in a computer model and then making predictions on what will happen in 1000 years is pretty silly. First of all if the fossil fuel usage and air pollution rates in China and other developing countries continues to rise as it has for another hundred years I don’t think there will be anyone left in those countries to worry about sea levels.
    If they made predictions just 500 years ago on what the year 2000 would be like assuming “a business as usual” future they would have said there would be a severe shortage of leeches available for medical “barbers”, a shortage of pigeons for communication, a shortage of mules for cargo shipping, of ink and pens for transcript copying. Imagine the rate technological advancement that we’ve had over the last 50 years continuing (or more likely increasing) for another 500 years. We have no idea what the world will be using for energy sources in 500 years.

  30. A collapse of the West Antarctic Ice Sheet may have occurred during the last interglacial period 125,000 years ago, a period when the polar surface temperature was around two degrees Celsius higher than today

    What!!! and CO2 levels were much lower than today! So how did that happen?

  31. They used not one, but two climate models, and not one, but two simulations to “feed the ice sheet model with all the necessary climate information.” Gosh, can’t argue with that. Their thoroughness is unimpeachable. /sarc

  32. So what about this continental drift ‘thingy’? How long before Antarctica wanders off and bumps into Oz or Nicaragua? Who needs a model for that? It’s obvious what will happen. Pooof! Instant defrost! The peaks of the Rocky Mountains will be a Pacific Ocean island chain. Tibet will have miles and miles of resort dotted, sandy, oceans beaches. The straits of Gibraltar will cease to be an easily defensible “choke point”. The Nile Delta will be on Somalia’s Mediterranean coast. We’re all doomed. Those rare pockets of humanity that survive will be plagued by an influx of homeless chattering, guano dropping penguins. I’m warning you! Time is running out. Act now! Write your congressman or congresswoman or congressperson or congressentity. Tell them to fully fund anti-drift research. Send your tax deductible donations to Driftpeace and save our future.
    Oow! I bit my tongue. How did it end up over there in my cheek?

  33. As a couple of people have already mentioned, volcanic activity well below the ice may account for the West Antarctica ice melt. In East Antarctica there is virtually no ice melt. It makes sense local factors rather than global warming account for the difference.

  34. If it gets really hot in the Antarctic, maybe monkeys will emigrate to that continent. They could make friends with the penguins. Bananas could grow down there if it was hot enough, and the monkeys might eat them. Maybe the monkeys could teach the penguins to eat bananas. A descendant of Donald Trump could open some hotels and casinos down there, and they probably would feature boxing events broadcast around the world via satellite. But monkey boxers would not fight penguin boxers, on account of them being friends.

      • I’ve been saying that for years.
        When, oh, when is some crazy entrepreneur going to take a breeding pair of polar bears and drop them off at a penguin colony in Antarctica. Obviously we would have to film the hilarious results for youtube.
        Just imagine the schizophrenic reaction from environmentalists – “the carnage must be stopped – but wait – we’re supposed to love and support polar bears – but wait – the carnage must be stopped…”.
        Hopefully after witnessing this, their heads would explode!!!!

  35. “How steeply and, above all, how quickly can the sea level rise in the future? …”.
    Questions questions questions.
    Will the Earth be struck by a massive asteroid?
    Will there be a massive Atlantic landslide causing a Megatsunami?
    Will there be a global viral pandemic?
    Will Bernie become POTUS?

  36. It seems the overall model is
    man + techonology => atmospheric CO2 increase
    => atmospheric temperature increase
    => water temperature increase
    => all floating ice melts
    => all land ice slides into water and melts
    => catastrophic sea level rise
    => PHD + funding
    Is there anything I’ve missed?

  37. WOW 5mm per year and that is a doomsday prediction.
    That is almost as funny as a meeting with the local council over our beach houses that are under threat from rising sea level and they wanted to stop any future development. We pointed out we wouldn’t be alive and so really didn’t care. Then they started with the crazy notion that the rate and tax payers were going to have to foot the bill. We walked them thru the process which is the same as building on an area subject to erosion for a beach house and the cost and risk is born totally by the land purchaser.
    Our council saw sense and we just sign paperwork saying we know the proposed house is at risk from sea level rise and off you go and build. You have warned us what happens from here isn’t your problem. I have heard of a few councils seeking to impose draconian planning laws based on projected sea level changes and I would hope people have the sense to appeal them.

  38. In 1927 a stationary landmark was erected at Waikiki Beach, Honolulu, Hawaii. It has been photographed, put on post cards, calendars and more on a daily basis since. It is the Royal Hawaii Hotel – the pink paradise of the Pacific. No matter how far back in time you go you see in the photos the ocean is always a matter of steps away from the hotel lobby. Never receding nor encroaching much, the tides alone provide any visual difference in water line. People need to pay attention to the reality of climate alarmism. It is just that – alarmist and nonsense. All the Hawaiian islands are subsiding as well as shrinking from natural erosion, but the hotel has not budged in nearly 100 years. According to Hansen the lobby should be entirely under water by now along with the subway entrances in New York City, and yet the distance from the lobby to the mean tide line today is imperceptibly changed from what it was in 1927.

  39. Ten months from now were are doomed. If after eleven months we are not seeing a dramatic rise in temperatures that is unlikely to be reversible then clearly climate scientists are frauds and should be in court more so that the bankers who mis sold products. More importantly no one has the slightest right to demand any taxation or subsidies based on climate science until it has been properly re examined not by peers of equal mediocrity to those in the climate science world but the superiors from other fields. We need proper experts in each area like signal analysts and marketing trend analysts for determining the normal climate progression. Engineering for establishing the quality of temperature measurement used for validatin the results and computer modellers, particularly from the electronics field for quality assurance testing of the climate models.
    What we do not need to to be forced to listen to the spouting of known and proven failures.

  40. Interesting; my nokia is hacked, can read anything in opera but WUWT. And no access to email account because of ‘unusal login’. Any way: no problem reading of and mailing to WUWT from the nokia’s OS because that’s SOP – same as it ever was. / just for a laugh.

  41. The TAlos Dome Ice CorE (TALICE) Project is a new 1620 m deep ice core drilled at Talos Dome. It provides a paleoclimate record covering at least the last 250,000 years.
    There WAS ice in Antarctica “during the last interglacial period 125,000 years ago.”

  42. The fact that the earth’s internal heat, which is sufficient to melt rock and iron and is constantly radiating outward towards the surface, heats the glaciers from underneath as it reaches the surface. The melting of glacial ice keeps the sub-glacial surface at a constant 32° F, and lubricates the bottom of the glacier to permit flow. Without the ice melting from geothermal heat, the glacier would not flow.
    I suggest that the heat reaching the glaciers from the rock below far exceeds the heat impinging upon the top surfaces of the glaciers from the air, which is often well below freezing.
    Glaciers melt from below.

    • Quite well, especially if you look at the 30% rather than 15% coverage. Also thickness. Area /extent at this time of year means rather little – September minimum is much more important .

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