New Paper Indicates Subantarctic Glacier Retreat More Extensive In 1700s Than Now

2nd Highest Subantarctic Glacier Advance

Of Last 1,000 Years Occurred 50 Years Ago

Yesterday we learned that a giant iceberg just split off from the Antarctic Peninsula.

Most media outlets were uncharacteristically mild with their declarations of concern.  Even The Guardian pointed out that the breakup of the ice is naturally occurring, glaciologists are “not unduly concerned about it“, and while the event “might look dramatic, experts say it will not itself result in sea level rises.”

Rolling Stone‘s Jeff Goodell, on the other hand, was not quite so apt to dismiss the importance of the Antarctic ice “crack-up“.  He insisted that there is a certain big-deal connection between the calving of the Larsen C ice shelf and both catastrophic sea level rise…

Given that Antarctica contains enough ice to raise sea levels about 220 feet … the break-up for Larsen C is certainly a big deal.”

…and human-caused “cooking the planet”.

“It is also well-timed politically. Larsen C has broken off just a month or so after President Trump withdrew the U.S. from the Paris climate agreement, when people around the world are wondering just how much time we have left before the climate spins out of control – and what to do about it. A story in New York magazine about how climate change is cooking the planet kicked up a lot of debate about the usefulness of fear in inspiring political change. Meanwhile, the responsibility for the Larsen C crack-up is already being doled out: Climate activists have launched a campaign to rename the now-liberated Larsen C ice shelf as the Exxon Knew 1 iceberg.”


Scientists: The Antarctic Peninsula Has Been Rapidly Cooling Since 1999


Apparently Jeff Goodell hasn’t been keeping up with the latest cryosphere science.

It is now well established in the scientific literature that the Antarctic Peninsula  – the location of the Larsen C ice break-up – has been cooling since the 21st century began.  In fact, the Antarctic Peninsula as a whole is cooler now than it was in 1979 (+0.32 °C per decade for 1979-1997, but -0.47 °C per decade during 1999-2014).

Glacier retreat in the region has begun to slow down or shift to surface mass gains.

And the ocean surrounding Antarctica as a whole (the Southern Ocean) has also been cooling since 1979, consistent with the overall trend of sea ice growth during this time period.


Turner et al., 2016

“Here we use a stacked temperature record to show an absence of regional [Antarctic Peninsula] warming since the late 1990s. The annual mean temperature has decreased at a statistically significant rate, with the most rapid cooling during the Austral summer.”


Oliva et al., 2017

“However, a recent analysis (Turner et al., 2016) has shown that the regionally stacked temperature record for the last three decades has shifted from a warming trend of 0.32 °C/decade during 1979–1997 to a cooling trend of −0.47 °C/decade during 1999–2014. … This recent cooling has already impacted the cryosphere in the northern AP [Antarctic Peninsula], including slow-down of glacier recession, a shift to surface mass gains of the peripheral glacier and a thinning of the active layer of permafrost in northern AP islands.”


Fan et al., 2014

Cooling is evident over most of the Southern Ocean in all seasons and the annual mean, with magnitudes approximately 0.2–0.4°C per decade or 0.7–1.3°C over the 33 year period [1979-2011].”


Comiso et al., 2017     

The Antarctic sea ice extent has been slowly increasing contrary to expected trends due to global warming and results from coupled climate models. After a record high extent in 2012 the extent was even higher in 2014 when the magnitude exceeded 20 × 106 km2 for the first time during the satellite era. … [T]he trend in sea ice cover is strongly influenced by the trend in surface temperature [cooling].”


New Paper Indicates Subantarctic Glacier Retreat Higher In Late 1700s, 1100-1550 AD


A new scientific paper reveals that modern rates of glacier recession – including the recent fate of the Larsen C ice shelf – are well within the range of natural variability.

Van der Bilt et al. (2017) have produced a glacier reconstruction for Southern Ocean islands near Antarctica (South Georgia) indicating glacier recession was more pronounced than today during the late 18th century, and that the second highest glacier advance of the last 1,000 years occurred in the 1960s and 1970s.  Only the peak glacier advances of the late 1600s were more extensive than the advances of ~50 years ago.

Similar to the recent Antarctic Peninsula and Southern Ocean cooling and nearly 4 decades of sea ice growth described above, this millennial-scale record of glacier retreat and advance supports the position that humans and variations in carbon dioxide concentrations do not play an influential role in determining the fate of polar ice.


Van der Bilt et al., 2017

Late Holocene glacier reconstruction reveals retreat behind present limits…

“Regional palaeoclimate evidence from the adjoining Southern Ocean region also reveal contemporaneous shifts. For example, reconstructed sea surface temperatures (SSTs) west of the Antarctic Peninsular rose 3 °C in less than a century (Shevenell et al., 2011). … Following the termination of a Late Holocene glacier maximum around 1250 cal a BP, warming created conditions unfavourable for glacier growth during the regional expression of an MCA [Medieval Climate Anomaly] between 950 and 700 cal a BP (Villalba, 1994). From 500 cal a BP [years before present], the Hamberg overspill glacier rapidly retreated behind its present-day position, possibly driven by local warming and/or major shifts in regional atmospheric and oceanic circulation patterns (Moy et al., 2008; Shevenell et al., 2011; Abram et al., 2014; Foster et al., 2016).”


To further put yesterday’s ice “crack-up” news into a long-term context, scientists have found there was a widespread (∼280,000 km2 ) collapse of the “world’s largest” ice shelf that occurred between 4,000 and 1,500 years ago.   Retreat rates averaged about 10 kilometers per century during this period.

Of course, this ice sheet collapse occurred while CO2 concentrations hovered near a stable 275 parts per million (ppm), which is about 130 ppm lower than today’s CO2 levels.

Succinctly, the Larsen C ice shelf calving event is not unusual, unprecedented, or even remarkable in the context of Antarctica’s long-term natural variability.


Yokoyama et al., 2016

Widespread collapse of the Ross Ice Shelf during the late Holocene

The Ross Sea is a major drainage basin for the Antarctic Ice Sheet and contains the world’s largest ice shelf. Newly acquired swath bathymetry data and sediment cores provide evidence for two episodes of ice-shelf collapse. Two novel geochemical proxies, compound specific radiocarbon dating and radiogenic beryllium (10Be), constrain the timing of the most recent and widespread (∼280,000 km2) breakup as having occurred in the late Holocene. … Breakup initiated around 5 ka, with the ice shelf reaching its current configuration ∼1.5 ka. In the eastern Ross Sea, the ice shelf retreated up to 100 km in about a thousand years. Three-dimensional thermodynamic ice-shelf/ocean modeling results and comparison with ice-core records indicate that ice-shelf breakup resulted from combined atmospheric warming and warm ocean currents impinging onto the continental shelf.”

32 responses to “New Paper Indicates Subantarctic Glacier Retreat More Extensive In 1700s Than Now”

  1. Graeme No.3

    I suppose it would do no good to point out that if floating ice melts then the sea level does not rise at all. Some people do enjoy a disaster tale.

  2. oeman50

    I am amazed to hear that Mr. Trump has the power to cause the ice shelf to calve (according to Rolling Stone) just by the the political act of withdrawing from the Paris accords. I bet he did not know he had that power.

    1. richard verney

      Especially since the crack that started the calving started about 100 years ago, ie., well before he was born.

  3. Brian W.

    Jun 15, 2017 HAHA!!! GLOBAL WARMING STUDY CANCELED, THE REASON WILL HAVE YOU ROLLING ON THE FLOOR LAUGHING!!!

    American Lookout reports, In a perfect example of irony, a scientific research study that intended to study global warming was cancelled after encountering large amounts of ice.

    https://youtu.be/MNn7lkO_dkM

  4. A C Osborn

    Calving is caused by Increasing Ice Mass and nothing to do with temperatures, Goodell knows nothing.

    1. SebastianH

      Ice gets pushed down and outwards over the sea. Ice being pushed exerts pressure on the ice flowing behind. Increased calving removes that ice, lowering the pressure, causing increased flow rate. This mechanism stops when no more ice is floating on the sea (max flow rate achieved). It largely depends on the temperature of the water.

      1. richard verney

        On the contrary, it largely depends upon snow fall in the interior; this is the force that you describe in the first sentence of your comment.

        The greater the snow fall, the more calving that has to take place. One sees this process very clearly in Greenland.

        1. SebastianH

          The greater the snow fall, the more calving that has to take place. One sees this process very clearly in Greenland.

          That’s true, but the less ice that needs to be pushed the greater the speed at which ice will be pushed into the sea by the snow/ice masses behind it. Thus calving of large ice fragments causes acceleration of the ice behind it.

          1. AndyG55

            Except the ice shelf broke AWAY from the glacier, it was not pushed. That is very obvious from the fact that the crack has been forming for ages. Pulling away, NOT being pushed.

            I take it you flunked basic mechanics, as well as science and physic, hey, seb.

            Or do you just INVENT contrary anti-science nonsense on purpose, as part of your child-minded trolling?

          2. SebastianH

            You two … always good for some strange arguments 😉

            AndyG55,
            what are you even talking about? Of course, the ice gets pushed by the ice behind it. Once a larger than usual iceberg calves it makes room for the ice behind it … which accelerates into the “gap”.

            You’ll see.

            Kenneth,
            don’t distract! Just talking about what happens after an icebergs calves. Nobody is saying anything about human CO2 causing any calving.

          3. AndyG55

            Stop distracting with your anti-science fantasies, seb-t.

            Gravity pulls.

            Are you really so mechanically illiterate that you can’t see that this recent glacier was not pushed, but cracked from the forces of gravity.

            Its bizarre that you just keep making up your own anti-science interpretations of everything, regardless of reality.. !!

          4. AndyG55

            Oh, and for those that don’t know, Here is a graph of the Total Antarctic Ice Mass since 1900.

            https://s19.postimg.org/fqrsmq8oj/Antarctic_ice_mass2.png

          5. AndyG55

            “You’ll see”

            In a vain attempt to educate seb-t,

            the Larson C is not a glacier, its an extremely thick ice shelf.

            http://inspimundo.com/wp-content/uploads/2017/02/5060238_6_6cc5_la-progression-de-la-faille-dans-la-barriere_99a8598b6daf87c0f1c241bc18070d2c.png

          6. SebastianH

            Oh come on you two …

            “Accelerated ice discharge from the Antarctic Peninsula following the collapse of Larsen B ice shelf”:
            http://web.ist.utl.pt/~nuno.j.aniceto/documents/stuff/documents/RignotetalGRLPeninsulaAccel.pdf

            @Kenneth specifically: distracting is rude, especially towards a guest. You do this all the time … and suddenly the discussion turns into a completely different one and goes back and forth with no progress and the original point gets lost.

            Iceberg calving causes the ice behind it to accelerate. Ice that wasn’t floating before enters the sea at a greater speed than before. While this causes a short term sea level rise it would only cause a permanent rise if the land ice mass permanently decreases. The end.

            Do you agree or disagree with that mechanic? Has that anything to do with how “they” (who cares?) named the iceberg?

          7. AndyG55

            “calving presumably happens due to bending stresses based on the boundary disturbances or the formation of giant tabular icebergs”

            See, they were PULLED, not pushed.

            seb-t’s make believe science, yet again proven WRONG by real science.

            Struggling to remember one tiny thing this little trollette has ever managed to get correct ?? !!!!

          8. SebastianH

            This is just asinine. As I’ve now written twice, I wasn’t even directing my comment at you.

            Your comment is a reply to my comment, not the one above. And you ask me at the end “So why do you believe that events like this (calving) are caused by human CO2 emissions?”

            How is that not directed to me? It’s you trying to steer the discussion in another direction and that’s rude.

            I was supporting Richard Verney’s comment about calving significantly resulting from ice mass gains

            … that thread is below this one. Here you are trying to distract from the topic at hand: calving affecting the ice behind it.

            What happens when ice shelfs collapse: http://web.ist.utl.pt/~nuno.j.aniceto/documents/stuff/documents/RignotetalGRLPeninsulaAccel.pdf

            I actually do care that journalists on your side actually believe that fossil fuels (Exxon) caused the ice shelf to calve. This is alarmist misinformation that too often gets passed off as real science.

            Alarmist misinformation like that “peer reviewed paper” that attributed all global warming to data adjustment? Turns out that it’s false … but you skeptics praised it as if all your dreams have come true at once … http://www.snopes.com/climatology-fraud-global-warming/

            Nope, I don’t think the Rolling Stone is correct on this one. But it doesn’t really matter to the topic at hand, does it?

            The original statement and reply was:

            On the contrary, it largely depends upon snow fall in the interior; this is the force that you describe in the first sentence of your comment.

            The greater the snow fall, the more calving that has to take place. One sees this process very clearly in Greenland.

            That’s true, but the less ice that needs to be pushed the greater the speed at which ice will be pushed into the sea by the snow/ice masses behind it. Thus calving of large ice fragments causes acceleration of the ice behind it.

            To which you added: “The Western Antarctic Peninsula is today several degrees cooler than it was during the Medieval Warm Period: [Links]
            So why do you believe that events like this (calving) are caused by human CO2 emissions?

            How is that not distracting?

            @AndyG55:
            Have you ever played Jenga? The lower blocks are pushing up against the blocks from above. What would happen if you could pull all blocks on the bottom level at once (calving)? Gravity accelerates the upper blocks downwards (ice behind accelerating) until the tower is resting on the table again. And so on.

          9. AndyG55

            Yet another numb-minded analogy from seb-t.

            Why do you always resort to those irrelevant idiocies when you run out of your other farcical arguments?

            The Larson C shelf broke from mechanical bending.. It was PULLED, not pushed from behind.

            The mechanics of the formation of the crack show that to be the case.

            You FAILURE to comprehend ANY sort of basic physics makes me wonder if you ever attended even junior high.

          10. SebastianH

            (I read messages from the queue in WordPress, which are not in the order in which they appear in comment threads that you see. Therefore, I assumed you were referring to my Greenland WWII planes comment.)

            I just wanted to point out that you then just clicked on the wrong reply link. That also explains why your comments sometimes appear in between older comments (which makes it difficult to notice them outside the comment RSS feed) and why you switch the topic or write about unrelated things in a thread sometimes.

            I’ll try to remember that next time and don’t assume you are distracting on purpose 😉

            The topic at hand is the subject of this article (that you apparently didn’t read) and the original comment in this thread: the extent to which temperatures/human activity affect calving vs. increasing ice mass affects calving.
            This paper says the southern oceans warmed: http://psc.apl.washington.edu/zhang/Pubs/Zhang_Antarctic_20-11-2515.pdf

            Warmer water/air certainly does have some effect, doesn’t it? Anyways, I put that in braces. The main point was that the ice behind such a large calving accelerates, increasing the flow rate from the mountains into the sea, at least temporarily.

            Khazendar et al, 2011 (Acceleration and spatial rheology of Larsen C Ice Shelf,
            Antarctic Peninsula)

            Wuite et all, 2015 (Evolution of surface velocities and ice discharge of Larsen B outlet glaciers from 1995 to 2013)

            @AndyG55:

            The Larson C shelf broke from mechanical bending.. It was PULLED, not pushed from behind.

            This is not about how the iceberg broke from the shelf … gravity is pushing from behind and pushes out the ice onto the sea. Everything that gets pushed and doesn’t move frictionless exerts a force backward that slows down the mechanism. If that something disappears that force disappears and the ice accelerates.

            Is that too hard to grasp?

          11. AndyG55

            You are WRONG as always, seb-t.

            The Larson shelf has been there of a long time.. There was nothing “pushing” from behind.

            The break is purely the action of its own weight and the cantilever effect PULLING the ice apart at the surface, and the crack eventually letting the berg loose.

            You would have to be TOTALLY IGNORANT in basic mechanics not to see this fact.

            Your CONTINUED DELIBERATE IGNORANCE in the face of massive SCIENTIFIC proof from K, is just what we have come to expect of you.

            It is tantamount to DELIBERATELY DISHONESTY and is the mark of a low-life troll, who’s only intent is to distract others from serious, rational discussion.

            Every post from you points out the fact that you are here for ONE purpose and one purpose only…

            … being a LOW-LIFE TROLL.

          12. M E Emberson

            Can you clarify that, please?
            On New Zealand television news we had an interview with the glaciologists who had been observing for 16 years the crack which completed recently and allowed a piece of an ice shelf to float away. It was not an iceberg calving off a glacier. They were careful to point out that the glaciers on land would not accelerate into the sea as the ice shelf was not connected to them. So this time the text book example of the glacier speeding up when a large piece breaks up did not apply, they said.
            I’m sure you will realise that reality is often not at all like textbook illustrations or demonstrations.

  5. John F. Hultquist

    Given that Antarctica contains enough ice to raise sea levels about 220 feet … the break-up for Larsen C is certainly a big deal.

    Non Sequitur
    (also known as: derailment, “that does not follow”, irrelevant reason, invalid inference, non-support, argument by scenario [form of], false premise [form of], questionable premise [form of], non-sequitur)

    Description: When the conclusion does not follow from the premises. In more informal reasoning, it can be when what is presented as evidence or reason is irrelevant or adds very little support to the conclusion.

    https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFallacies/136/Non-Sequitur

  6. AndyG55

    In 1956, and iceberg FIVE TIMES THE SIZE broke off, and it was the second calving that year.

    https://realclimatescience.com/wp-content/uploads/2017/07/Image1581_shadow.png

    Seems to me that “claimate change” is making smaller chunks break off.

    Hint.. Glacier is literally a “river of ice”

    What would happen if it didn’t calve occasionally !

  7. Eisige Antarktis: Riesiger Eisberg bricht unter wachsender Last ab! Antarktikeis wächst seit 10.000 Jahren! – wobleibtdieglobaleerwaermung

    […] New Paper Indicates Subantarctic Glacier Retreat More Extensive In 1700s Than Now […]

  8. Albert Stienstra

    In fact, calving icebergs of this kind, borne by ocean currents, will help cooling the oceans a little.

Leave a Reply