Arctic Newsflash! Petermann Ice Tongue Loses Huge Chunk
    By Patrick Lockerby | August 5th 2010 09:43 AM | 51 comments | Print | E-mail | Track Comments
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    Arctic Newsflash! Petermann Ice Tongue Loses Huge Chunk

    I have been watching the Petermann Glacier ice tongue for some time now.

    Here is what I wrote in  Arctic Ice July 2010 - Update #3:
    Judging from historic maps and images, the normal behavior of the Petermann ice tongue was the formation of a concave front at the fjord mouth.  Over recent years it has retreated.  Much of the tongue is now detached from the walls of the fjord.  Tidal forces will flex the tongue up and down: wind, currents and ice floe impacts will all exert at least a small lateral force on the tongue.  It will continue to thin from melting.

    Judging by previous behavior and by the forces which will act on a more mobile ice tongue, I predict some dramatic calving this year.  The image below shows red lines where I expect the tongue to calve.  This is based on moraine and meltwater channels seen in other images from last year, and previous calving.  Please note that this is more of an educated guess than a scientific forecast.  Although there is a large fracture further upstream, it is quite old and may well be healed with solid ice.  That part of the glacier is in compression across the fjord, which will - I suggest - reduce the likelihood that the fracture will grow - until it has move a substantial distance such as to relieve the transverse compressive forces.

    Projected breakup of part of Petermann glacier tongue.

    The Petermann ice tongue tip has held almost the same shape since winter 2008.  It has had nearly two years in which to thin and crack.  I would be very surprised if it does not retreat substantially this year.

    In Arctic Ice July - Update #4 I wrote:
    The Petermann ice tongue looks primed to lose a few fairly large floes any day now.  There are a lot of cracks showing at 250m resolution. 
    That means the cracks must be at least 250m wide.

    It looks like a few small bergs- about 2 or 3 km across - are going to break off before the main tongue breaks up.  The bigger fracture back at the tributary glaciers needs a lot of back-pressure relieved before it can expand much.

    The Petermann ice tongue tip has held almost the same shape since winter 2008.  It has had nearly two years in which to thin and crack.  I would be very surprised if it does not retreat substantially this year.

    The latest cloud-free MODIS / aqua image shows that a substantial mass of ice has just broken off.

    Petermann Glacier Floating tongue broken off August 05 2010

    image source:

    Further reading, updates and more comments:
    The Anatomy Of A Discovery - Petermann Glacier Ice Tongue Calving 2010
    Petermann Glacier Calving 2010 - Update
    Petermann Ice Island Revisited

    Related reading:

    More Arctic articles:
    The ChatterBox Arctic Index


    What an image. I'm speechless...

    Do you think the ice in front of the big rift on the right will break off this season as well?

    Going by Google Earth the fjord is about 15km wide. Based on
    that I would say the Lockerby Iceberg is about twice that size across. Roughly the size of Andorra.
    I've made an animation:

    Man, that looks awesome!
    That's a really impressive prediction come true. Well done. What a huge event!

    Greg: thanks for your kind words.

    btw, I'm old enough to remember that a 'well done' is much nicer than a Harvey Smith.  :-)
    Neven: I was going to link to your blog, but as you've kindly posted the animation here there is no need to link to your blog.;-)

    What your animation shows more clearly than the composite which follows is the anticlockwise rotation of the tongue tip.

    This composite of four aqua images shows just how slowly the mass of ice rotated.  The slow rotation is understandable given the scale of this ice island.

    It is exceedingly difficult to judge at this scale, but I would expect to find an underwater obstruction - perhaps solid rock - at the pivot point.  That would convert a longitudinal compressive force into a transverse shear force.
    The movement of sea ice away from the glacier is cool too. Perhaps as it rotated it produced a big wave or pulse of water that moved that loose ice out into the straight.

    Certainly a number of "isolated events" this year. Or maybe not. I hope someone with more time on their hands than I can calculate the probability that the "random isolated events" we are seeing this year are in fact "random isolated events."
    Just a wild guess, but I would hazard that the odds of these events being unrelated are very tiny.

    Shouldn't this be the time the global warming skeptics show up to make some smart-assed comments? It isn't that this is such a powerful piece of evidence of AGW, but that scientists predicted it through observation, and it happened. It's almost like science is more rigorous than sitting on a bar-stool swigging Sam Adams and ruminating mindlessly about how Popular Mechanics once ran an article about global cooling.

    Shouldn't this be the time the global warming skeptics show up to make some smart-assed comments?
    But they have their own blogs and cheerleaders for that purpose.  The acolytes will applaud their feckless leader as he proves conclusively that this event proves conclusively that sea levels were conclusively higher about 1,000 years ago during the bronze age ice age and that the Chinese and the Vikings built a huge network of canals through Greenland under contract from the Egyptians who wanted inland passages for their papyrus superfreighters.  Or something.

    A large piece of Old ice has broken of next to Ile of France (Northern Greenland), aprox. 300km2, and I believe more is to come in the area of same magnitude.

    Thanks, Espen.

    If you mean the chunk in the smaller circle, below, I make it 200km2, but let's not quibble as it will soon be just bits.  ;-)

    I have been watching Flade Isblink, Zachariae and 79N glaciers.  My main point of interest is the area within the larger circle.  You can make out in cloud free images a number of huge tabular bergs in a sort of 'funnel' of islands.  If the ice melts enough we will be able to see if those bergs are grounded or just trapped by sea ice.  If the ice melts up to the calving fronts of Zachariae and 79N we may see some significant calving.

    Hi Patrick,

    I believe the ice is very well packed away behind that ridge of islands, so unless it really melts up there it will be trapped.

    Hi Patrick,

    Yes its the piece next to Isle of France, I believe we will see a lot of big pieces leaving the old ice from "Bear Island" ( I dont know the name of it, but it looks like a bear) in the south up to Flade Isblink in the north over the next coming weeks, and by my estimates we will have a record low of solid/ not fragmented ice this season, less than 5 %!
    The seals up there must enjoy it up there with all those breathing holes, but what the polar bears? It must be a very bad hunting season for them!

    I assure you the polar bears are doing just fine and have become quite a nuisance in my home town. That I why I make sure to put a bullet through the head of at least 3 a year and sell the fur.

    Indeed, I finally finished watching David Barber's plenary talk at the last IPY meeting. He says that rotten ice can actually be an advantage for polar bears.

    Nevertheless, I hope that one day your gun doesn't work, Polar Bear Hunter. :-)
    Independent corroboration that this ice cube is a real whopper:

    A University of Delaware researcher reports that an "ice island" four
    times the size of Manhattan has calved from Greenland's Petermann
    Glacier. The last time the Arctic lost such a large chunk of ice was in
    Trudy Wohlleben of the Canadian Ice Service discovered the ice island
    within hours after NASA's MODIS-Aqua satellite took the data on Aug. 5,
    at 8:40 UTC.

    But got the scoop!  :-)

    If this was a comet it would be called Wohlleben - Lockerby.  I'm glad it's not a comet. :-)

    How about "Chatter-box Island" - just amongst ourselves? ;-)

    I'm still studying this and hope to write a follow-up soon.   First reactions:

    If this ice island drifts into Nares Strait without breaking up it will completely block sea ice export from Lincoln Sea.  That would significantly affect sea ice losses.

    If the shock of calving was great enough and if the calving has removed significant back-pressure then we may see another large calving event soon.  Depending on how the stresses realign themselves I would expect another ice island to calve either within two weeks or next summer.

    The arrow shows my estimate of the center of rotation.  The shear and tensile forces will have left a fairly narrow zone prone to more calving - to the red line across the ice tongue.

    The arc follows the old and large fissure.  If the new front is not able to move forward smoothly then there may be another rotation with the arc as its rim.

    Once the new calving front stabilises I would expect it to have the same notched appearance that the former front had.
    Independent corroboration that this ice cube is a real whopper: Greenland glacier calves island 4 times the size of Manhattan
    Since you are in the UK, aren't you obligated to compare it to Wales?  Like 1/80th the size of Wales or whatever?
    Ok, Hank, here goes:

    It's a 1.5 Isle of Sheppey size ice island -

    plus or minus 4 car parks -

    give or take a few cars -

    Life is so unfair.  (Sob, sob!)  I predicted this event with reasonable accuracy as to size and time and was then the first to report that it had happened.  And what do the media report?  The stuff they get from news feeds.  And then there's the 'added value' of reports about how this giant ice island is going to be a menace to shipping.  Hardly!  Unless it breaks up it won't even get past Irsyad Island, Hans Island and Franklin Island.  Heck, it will have to perform a limbo dance just to get into Nares Strait.

    Sour grapes?  You bet your sweet bippy!
    You're second in Google for Petermann ice - but media relying on other media can't really be a big surprise.
    It's the #2 most read story on as well at the moment. Never mind Patrick ... at least we know that you were the first to break it!

    What's this? Did Patrick break the Petermann Glacier? What people won't do for a scoop... ;-)
    Never mind Patrick ... at least we know that you were the first to break it!

    What's this? Did Patrick break the Petermann Glacier? What people won't do for a scoop... ;-)

    Too easy!  Mind you, the solar flare that I used to trigger this calving was a bit tricky!
    University of Delaware bla. bla.

    This story is just bull shit, the ice island from the Petterman glacier was found long before by Patrick Lockerby, and not by Mr. Muenchow or rather Munchhausen.

    Best regards Espen

    Next phase of speculation: Patrick, do you expect Lockerby Iceberg to block the Nares Strait?
    It will take a while for Lockerby to get out of the "cave", and that will probably be in smaller pieces, and downstream the Kennedy Channel it might get stucked by the Hans, Franklin or Crozier islands, i dont think it will make any greater impact, as things are at the moment.
    Just 1 ? How thick is it on average, and much of that thickness is above sea level?


    For those interested USCGC HEALY is now back in the arctic sea you can follow her via web cam on

    Friends: thank you all for your supportive comments.

    I said in a comment above "If this was a comet it would be called Wohlleben - Lockerby".

    In fact, I have no objection to it being named the Lockerby-Wohlleben ice island.  That is the order of names if it were a comet. In full it might be B/2010 01 Lockerby-Wohlleben - B for berg rather than the I for island which may be confused with 1 or L in some fonts.

    Priority is important in science - not for personal aggrandizement but for reputation in the science community.  As my regular readers know, I am constantly trying to counter the propaganda emanating from people who want the world to believe that global warming and climate change are fictions.  I predicted this event as to approximate time and scale.

    The media is reporting that 'nobody predicted' the scale of the ice island.  But I did - it's a part of web history.  I also reported the second calving of the Jakobshavn glacier.  Getting proper credit for these and other predictions is important.  It means that more members of the public are likely to be persuaded that climate change is really happening and that it is a problem.

    I predicted a 2010 minimum Arctic ice extent of 3.5 to 3.8 km2.  I stand by that.  It is important that my prediction is recorded: right or wrong it will be a part of my record in Arctic studies.
    News update:

    I spoke to a very helpful person at BBC news and have been given credit
    for my prediction.

    Patrick Lockerby, a UK engineer with a background in material science, told the BBC he had predicted the calve on 22 July, posting images on the science2.0 website.

    "I was watching the floating ice tongue wedged between two walls of a fjord for three quarters if its length with the last part at the outlet end wedged by sea ice. I thought once the sea ice was gone, the pressure would be too great and the tongue would calve."

    He said there could be a beneficial outcome if the calving drifts to block the Nares Strait and effectively prevents the loss of more ice from the Lincoln Sea.

    Considering the constraints imposed by the number of words allowed and the target audience, that is a fair summary.

    As to the matter of priority and publication dates and times, I have emailed Trudy Wohlleben suggesting we should call this the
    Wohlleben - Lockerby or Lockerby - Wohlleben ice island.

    But somehow I have a penchant for calling this the "Biggest Arctic Glacial Ice-Tongue Island Ever - One More Bit Of Evidence For Global Warming - Petermann" ice island.  ;-)

    Hi Patrick,

    Greenland is soon giving birth to an ice island bigger Singapore!

    We could soon see a Monster break away just north of Ile de France (north east greenland), it could be anything between a few hundred up 800 km2, thats bigger than Singapore (710km2), so watch up.
    And I am happy for your support regarding Lockerby Petterman ice island.

    Hi Espen.  You are quite right.  There are some big sheets of ice on the move there.

    Much of the ice in that area is old and thick shorefast ice.  Some of it is melange: a mix of sea ice and bergs.  Ice islands forming in that area tend to get banged about a lot and they are in quite warm water and air, so they break up rapidly.  They also tend to get pressed against the coast and grounded from time to time in their journey south.  As soon as sea ice starts to reform they get frozen in again.

    Ice Island spawns crazy reporting.

    The author of a blog reports a note of alarmism in the way the media has addressed the news about Petermann glacier:
    A HUGE lump of ice has broken off from Petermann Glacier in northern Greenland. Andreas Muenchow, of the University of Delware’s College of Earth, Ocean, and Environment, says the ice sheet covers 100 square miles. Trudy Wohlleben of the Canadian Ice Service, was the first to report the broken ice. Neither mention global warming being behind the split.

    Hmmm.  OK.  Apart from the caps-lock problem which often warns of an agendist at work, this is what the media is generally reporting.

    Not Global Warming

    Prof Andreas Muenchow “said it was not clear if the event was due to global warming.

    The scientific fact is followed by the BBC hack saying:

    The first six months of 2010 have been the hottest on record globally, scientists have said.

    BBC hack?  Someone has an agenda.  Can you guess what it is yet boys and girls?

    CLIMATE change has been blamed for floods that have killed thousands and left millions homeless from Pakistan to North Korea, fires and a heatwave in Russia that have left 5000 dead and disrupted global food markets, and a severe tropical storm threatening Bermuda.

    In Greenland, a giant ice island four times the size of Manhattan – about 225 square kilometres – has broken off the Petermann Glacier. It is the largest chunk of ice to calve in the Arctic since 1962. – SMH

    Largest since 1962?  Comparing ice shelves with ice tongues isn't quite comparing apples with apples, but let's not get too pedantic.

    Environmentalists say ice melt is being caused by global warming with Arctic temperatures in the 1990s reaching their warmest level of any decade in at least 2,000 years, according to a study published in 2009. Current trends could see the Arctic Ocean become ice free in summer months within decades, researchers predict. – CNN

    The article on is titled

    Warmists Sell Petermann Glacier As The Global Warming Titanic

    Er - well - it almost makes some kind of sense.

    And the author's 'proof' that this ice island, the biggest chunk of glacier tongue ever recorded, has nothing to do with global warming?

    But the ice did not melt. The ice cracked.
    Yes. Sure. Right.  But what made it crack?  The ice-cracking fairies?  Solar flares?  Conspiratorial warmist agendist neo-nazi commie tree-hugging trendy lefties?

    Ever see a car on fire?  I mean in real life, not the movies.  First the flames can be seen through the glass, then the glass gets covered in soot.  And then the glass shatters.  Nothing whatsoever to do with all that heat: the glass cracked.

    What part of 'thinning' does this person not understand?

    The ice island calved after a couple of years of thinning.  The thinning was due to the meltwater from above and the warm water below.  The ice cracked because it was primed to do so, having been substantially weakened by warming and having been relieved of its lateral compressive forces by warming.

    This is not proof of global warming.  It is just one more piece of evidence to add to a mountain of data which points strongly to global warming being a fact rather than 'just a theory'.

    Oh, yes: I nearly forgot:

    Trudy Wohlleben of the Canadian Ice Service Patrick Lockerby on, was the first to report the broken ice ice island.

    There!  That's better!

    Chatterbox island is getting some press
    "Muenchow said he had expected an ice chunk to break off from Petermann, one of the two largest remaining glaciers in Greenland, because it had been growing in size for seven or eight years. But he said he did not expect it to be so large."

    You did predict the size pretty well

    Important news::

    Hi Patrick

    As earlier reported, the huge ice island north of Ile de Frands, size larger than Singapore has now left its safe harbour and are drifting out to its sure death.


    Hi Patrick

    Additional info about the the new Monster Ice Island of North East Greenland, is more then 900km2.

    Regards Espen

    Hi Patrick,

    Doing some more home work about this new Ice Monster, I will change the size to around 700km2 or 270 square miles, but still sizeable, I believe, the whole area seems to disintegrate these days and there will be a lot more to report on in the coming period.

    Best regards Espen

    Here is a link to the break away Ice Island

    Image cropped from Modis Aqua


    Thanks for the info Espen.

    Here is your image:

    It's a big one!  It's hard to tell how old the ice is, but there must be some ice at least 3 years old in there.  However, it's the youngest ice that tends to give way first, so this will most probably break up within the week.

    Note to readers: the two lines across this ice island on Espen's image are artifacts of MODIS image processing, as are most of the horizontal line pairs seen.

    Your 'Bear Island', bottom of image - an apt name!

    This is Shannon Island.  It is a very interesting island as it is a source of much information about the state of Arctic ice in the 1940s.

    Enjoy the free pdf:

    Hi Patrick,

    Just happy to add something to your very informative site, "keep on going", the season is far from over yet!

    Regards Espen

    More blogging on Chatterbox island this time Climate Progress. I did not see an acknowledgemet of your contribution, but Colerado Bob did put a link to your site in the last few days.

    We knows yous was firstist

    Hi, Tony.  Thanks for the link.

    They got a lot more right than most sites, and even linked to the news release as their source for the claim of discovery.  However, an unqualified connection to sea level rise needs a caveat: this ice island will not contribute to sea level since it was already floating before it detached.

    I liked this:
    To put the Petermann Glacier’s latest ice island in perpective, the island’s area of at least 260 sq. km is well over twice what all 34 glaciers surveyed by the  Byrd Polar Research Center have been losing annually (-106 per year).
    I have left a comment requesting a correction about who discovered what.  :-)

    I just published a new article:
    The Anatomy Of A Discovery - Petermann Glacier Ice Tongue Calving 2010

    you must have missed when Neven Island (sorry should that be B/2010 00 Neven? ;-) ) broke away from just north of where your ice island was born. Neven calculated that at the size of Corsica - 8,500 sq km.

    Mind you it didn't last long - after 10 days of sitting in a warm north-flowing current, it had turned into the worlds biggest slushie...

    You can see its birth and death here:

    FrankD: yes, I saw that.  That was nicely spotted by Neven - the more so since I regularly check the Flade Isblink and Zachariae area for activity - but completely failed to spot this one coming!  :-)

    Did you see my article Jakobshavn Glacier Second Calving ?

    The media picked up the J North calving news and hyped it for all it was worth.
    They completely failed to mention the second and bigger calving of J South a few days later.
    Wow ... even the ESA finally noticed!   :)

    Hank: it may be just the way my mind works, but it looks like Jakobshavn is giving the climate change deniers the digitus impudicus.  ;-)

    That is the best link on the whole web, ever!  Thanks.  But it needs editing:
    Hi Patrick,

    Just watching the latest images from Modis Terra, and the whole lot of ice around Ile de France (North East Greenland) is "exploding" in all directions, so Ile de France will probably be ice free on its eastern shore this melting season, and when did that happen last time? It must a record loss of ice in that area, and it is one of the last areas in Greenland where old ice is stucked to the shore, so I would soon calculate not fragmented ice in percentage of ice extend to less than 5 %

    Pretty dramatic scenes On the east coast of Greenland, in the area between Silverbergs Island and Ile de France, I estimate we have lost around 1000km2 of shore ice within the last 24 hours, and a big crack is showing up at the "frontdoor" of Zachariae Isstrøm and 79 North Glacier, so the remaining +/- 400 km of +1 years shore ice from south of Flade Isblink and south is at risk even within this melting season, soon Greenland will live up to its name!

    Espen: many thanks for reminding me.  I already downloaded some of today's clearest near-real-time images of this area, but got side-tracked.

    There are signs of some calving which is being prevented by the buttressing sea ice.  You can see the old, large tabular bergs from Zachariae in the bottleneck of islands.  They seem to be about to shift.  You can now see the small ice tongue clearly, poking out between islands.  The white arc is a whole year's supply of bergs by the main calving front, just waiting to scatter.

    Article now in preparation: I may post tonight, UK time, if I don't nod off. :-)

    btw, thanks for posting the link to my blog with your recent image.
    Hi Patrick,

    I am just wondering, what is your immediate reactions and answers to whats going on in North East Greenland, I am thinking of the coast from Shannon Island (Bear Island) in the south to Kronprins Christians Land (northern point of East Greenland). I see +1 years old ice literally breaking off in very big pieces and evaporating in few days in the currents of Fram Strait, and we will see very little +1 years ice after this season compared to what I know about, and probably much more than 50% of the ice that was there just only last year is now gone, and we probably only 1 year away from a total ice free east coast in the melting season?

    1. When did this happen last time?

    2. What effect will it have on local climate?

    3. How will the glaciers in the area react ( we got some big ones there)?

    4. What about the sea currents in the area?

    5. Will it affect the rest of the Arctic Sea further north?

    You don't have to answer these questions in a scientific way, just your immediate answers, they are probably just as good! ( I have a good gut feeling when it come to your judgment), but hope you are too busy!

    Best regards Espen

    Espen: good questions!  You are a bit ahead of me here.

    I had intended to write this up last night but had a migraine.  I still am on the tail of it.  That tends to knock a big hole in my productivity.

    From roughly Shannon Island through Flade Isblink and 'round the corner' there is almost always a great loss of sea ice in at least some areas.  Within the area bounded by the sea ice, the melting of ice in fjords is also common.  Whatever the state of the Arctic sea ice, there is always a fair sized area free of ice just off Flade Isblink - it's called the North East Water polynya.

    The Zachariea and 79N glaciers both sit in basins below sea level.  There is a line running roughly north-south of shallower basin at their outlets, also many islands.  A total loss of sea ice here would increase the calving rate - less for 79N than for Zachariea.

    The less sea ice there is in that part of Greenland, the more freely ice from the main pack can exit if being driven south.

    I'll try to get my new report up tomorrow.

    You don't have to answer these questions in a scientific way, just your immediate answers, they are probably just as good! ( I have a good gut feeling when it come to your judgment), but hope you are too busy!
    I am fond of telling my readers: "Please don't let me do your thinking for you."  So please check what I say against what others might be saying.  Let the evidence speak.  If the evidence speaks and tells you that I don't know what I'm talking about, then please do come back and say so.  I welcome criticism.

    To the best of my recollection, apart from spam, I have only ever deleted one comment.  But that was because it was so rambling that I didn't understand it - and I'm a linguist!  :-)
    Hi Patrick,

    Another 2 huge ice islands (one is +1000km2) , are leaving the large pack of ice North East Greenland, next to Kronprins Christians Land just south of Flade Isblink.

    Regards Espen