the Air Vent

Because the world needs another opinion

Antarctic Sea Ice Complete Video

Posted by Jeff Id on June 30, 2009

Antarctic temperatures and sea ice are becoming quite a hobby. It should make for some interesting discussion around the campfire this summer – not really. It takes my computer about 15 hours to calculate this movie and it took all day to figure out how to make the movie work. Actually it takes a minute then wait, then a minute and wait again. I finally got a reasonable quality video at 15 frames per second, one frame per day from 1978 – 2009. Before you watch the video Figure 1 is a map of the Wilkins ice shelf which apparently is about to melt every hot January summer at the south pole.

A map of the Antarctic Peninsula with the location of the the Wilkins Ice Sheet, which is on the southern portion of the peninsula. Credit: British Antarctic Survey

Figure 1 - Wilkins Ice Shelf - A map of the Antarctic Peninsula with the location of the the Wilkins Ice Sheet, which is on the southern portion of the peninsula. Credit: British Antarctic Survey

The melting of the Wilkins ice shelf has happened over and over prompting numerous articles like the following.

Wilkins Ice Shelf About to Break Off and Alter the Map of Antarctica

Vast Antarctic Ice Shelf on Verge of Collapse

The headlines are truly endless and will continue this year as well.

Here is a video which is particularly pertinent in it’s discussion and the fact that it ends with a discussion of climate science by Hillary Clinton. I recommend it to everyone before watching the video below.

Wilkins Ice Shelf Collapse Video

Below is a plot of the sea ice area anomaly in the antarctic calculated from the NSIDC NasaTeam algorithm data. It shows an upward trend in sea ice extent over the last 30 years.

south-ice-anomaly1

Figure 2

I’ve pointed out here many times that the trends do in fact exist if the even if the statistical certainty created by typical high frequency climate activity can create a trend of the same magnitude. This is an important differentiation which certain ‘over the top’ scientists in AGW crowd tend to blur. Statistical certainty of a trend does not always mean the trend does or does not exist, a trend is a trend to the certainty of the measurement error (different than certainty created from other noise). Some global warming bloggers like to blur that distinction.

The interpretation of a trend’s meaning does change with the statistical certainty of the trend. In the case of Antarctic sea ice growth I have seen one example demonstrating the trend is statistically significant despite climate noise. However the point of ice shrinking or growing is to interpret the consequences of a trend with regards to global warming. When interpreting the consequences of ice growth or shrinkage in my opinion the arbitrary significance threshold and linear trend has little meaning.

The annual variance of the sea ice is shown in Figure 3.

south-ice-area1

Figure 3

The huge annual variation dwarfs any apparent trend with the signal dropping to near zero every year. The thermal inertia of the ice creates a smooth cyclical process allows us to make pretty anomaly plots like Figure 2 but trend wise there isn’t much to say. So I guess I’m fired from my budding climatology career again. The reason they have little meaning becomes apparent in the wildly dynamic sea ice video presented below.

Below is a link to a video file of the Antarctic sea ice trends for 30 years.

Antarctic Sea Ice Video - Click to play

Figure 4 - Antarctic Sea Ice Video - Click to play

Now consider that each pixel of the Antarctic ice data is 25 km and in the video of the Wilkins ice shelf, the crack is 40miles long – that is about 2.6 pixels in the Figure 4 video.

What’s really interesting about the video is the clockwise rotation of the ice which becomes especially visible during maximum extent. Another interesting point is the peninsula acts as a shelter to the ice on its leeward side. The Wilkins shelf get’s blasted by air and water currents every year from the south in this image, once we understand that combined with in the CNN video (link above) the reason the ice bridge exists is obvioiusly due to protection from ocean and air currents by a small island (look at the angle of the ice bridge in the CNN video compared to current flow). The Island has protected this very small piece of ice from cracking for some time probably because the amazing circularity of the Antarctic continent doesn’t experience very large current changes.

I’ve watched the above video a dozen or so times (wouldn’t you after a day’s work) I noticed that there does appear to be a change in weather patterns in more recent years as the upward flow below the peninsula cuts away at the maximum ice extent on the West side of the image. The same is true for the East side of the image.

I had the advantage of doing a trend by pixel plot previously which led me to look for the effect. The plot done by myself in a previous post using a slightly older version of the same data is shown in Figure 5. The loss of ice on the West and East sides of the Antarctic is visible as blue pixels at the extreme edges of the range.

All points have a minimum of 20 months of data, forced a scale change +/- 15Km^2/Year

Figrure 5 - Antarctic sea ice trend by pixel

Its difficult to imagine after watching this video that this ice shelf hasn’t collapsed (or whatever it’s called) and re-formed in the last several hundred years, more than once. Remember the ice from the shelf forms on land and flows out to sea. Either way, considering the natural variation of Antarctic sea ice, can we really say the current Antarctic ice trend or the change of an ice shelf in such a tiny area has a powerful meaning for the future of Earth?

If you missed the Arctic version of the video the link is here: Arctic Ice Video

55 Responses to “Antarctic Sea Ice Complete Video”

  1. Arn Riewe said

    Only about six more months until we can hear Dr. Ted Scambos from NSIDC pontificate on the “extremely rare” cracking of the Wilkins Ice Shelf that he announces annually for about the last 15 years.

  2. Phil. said

    I can’t see the Wilkin’s lasting much longer following the major losses this year. My understanding is that it’s not fed by glaciers (v minor) and that it’s the underwater melting of the sheet from its ‘pinning points’ that is causing the breakup. I expect the focus next year will be if there’s any further breakup of the bridge to Latady which will be the remaining support of the sheet.

  3. rephelan said

    Jeff,

    That is fascinating. I simply was not aware of the annual extent of melting and refreezing. From your movie, it looks like the Wilkins shelf nearly disappeared in the 80s and again in the 90s. Watching that movie and your earlier arctic one, I have to keep asking, not “why is it melting”, but rather, why isn’t it melting more?

  4. You apparently did a lot of work and forgive me if I ask something that cannot be done, but do the data allow you to zoom in on the Wilkins area and really show how often it has been ice free in the past 30 years? When I see the movie there are some blue flashes every now and then in the vicinity, but not enough to really be able to judge/count it.

    Otherwise, keep up the good work.

  5. Jeff Id said

    My understanding is that the Wilkins has not been without ice for the last 30 years. I think the satellite data has the area in question masked out as brown land. Some of the pixel flashes are just noise from the sensors and some are from the video processing. I used free software.

    Sorry I can’t be more helpful. It’s amazing seeing how much variation and movement there is though isn’t it.

  6. Nic L said

    Jeff,

    Excellent video – good work. Am I right in thinking that certain “permanent” ice shelves are treated as part of “land” in the satellite images – e.g., Ross (and Ronne and Amery?)

  7. Nathan said

    Are you seriously suggesting the Wilkins Ice shelf is less than one hundred years old?

  8. Jeff Id said

    #7, No idea honestly. Can you tell me how old it is? – It’s a real question because I’m an engineer who downloaded a huge pile of data on sea ice which almost completely melts and refreezes every year.

    As an aeronautical guy, I am quite capable of blogging on boundary layers, pitot probes, structures, optics, fluids, programming, rocket engines, electronics, filters, math, thermodynamics, interferometery and a few other details however, I’ve got no idea how old the ice shelf is supposed to be. Also, I’ve got no idea how the age of the shelf is determined so I’m happy to be enligtened as are many of the readers here.

    Are you suggesting the Wilkins ice shelf doesn’t collapse regularly? — I doubt that very much but I’ve been wrong before.

  9. Fluffy Clouds (Tim L) said

    what i saw is the close call to getting ice to the south American tip, and the island to the east gets ice to it (1980,?) there must be some very hard currents through south American tip, or volcanic activity.
    nice work :)

  10. Nathan said

    Jeff

    Go to google scholar

    Search for “Wilkins ice shelf dating”, for example

    Then start reading.

    Most seem to indicate an age of around 6000 years (the Holocene Maximum)

  11. Jeff Id said

    Here’s what I found in one minute. This is not conclusive but do you think they really know? How is it possible this shelf lasted as long as they think in these sea ice conditions? You can see the melt and reformation of so much ice, do you think it’s possible the sea ice was mis-dated due to flow from the older ice in the mountains?

    But the Wilkins Ice Shelf is a different breed in the way it forms, explains Dr. Vaughan.

    Although it’s been stable for as long as scientists have been able to reach the continent and study it, the shelf scientists see crumbling today appears to have formed either between the Roman era and the Medieval Warm Period or with the onset of the Little Ice Age. Indeed, he adds, “it’s kind of a come-and-go ice shelf” compared with the other vanishing shelves, which have been stable far longer.

    Wilkins appears to have started as seasonal sea ice that gradually thickened, Dr. Vaughn adds. Shelves built of glacial ice are stout, because the weight of each succeeding winter’s snow has compressed the layers beneath until the glacial ice becomes solid.

  12. Nathan said

    Jeff,
    you found one that doesn’t actually show any dating.
    There were plenty in there that used dating of sediments, they give much firmer dates.

    http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=217139

  13. Nathan said

    Jeff,
    you found one that doesn’t actually show any dating.
    There were others in there that used dating of sediments, they give much firmer dates.

    http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=217139
    they give dates of 5750–6000 14C yr BP for the George VI ice shelf (immediately south of Wilkins)

    Remeber the ice shelf was very big, over 100m high. It is not sea ice either, there is a difference between the shelf ice, and sea ice. From wikipedia: “The thickness of modern-day ice shelves ranges from about 100 to 1000 meters”
    It is clear that thick ice like that can survive a long time. Once you start to thin the ice (whether by warmer water or any other method) it gets weaker and will snap once it is too thin.

  14. Layman Lurker said

    Here are a couple of interesting Q&A’s with Angelika Humbert on the Wilkins Ice Shelf:

    http://www.sciencepoles.org/index.php?/articles_interviews/angelika_humbert_on_the_future_of_the_wilkins_ice_shelf/&uid=1461

    http://www.sciencepoles.org/index.php?/articles_interviews/angelika_humbert_on_the_future_of_the_wilkins_ice_shelf/&uid=1461

  15. Jeff Id said

    #14, Thanks for the link, it was interesting.

  16. Mike D. said

    Just absolutely excellent. Would get my vote, if I had one, for an Academy Award.

  17. mpaul said

    Jeff, well done!

    Is it possible to put two circles in the animation: one whose area is equal to the area of the average annual maximum extent over the animation period and the other whose area is equal to the area of the average annual minimum extent?

    I know that the ice extent is not circular, but this would give your eye a reference point and might make it easier for a journalist to grok.

  18. Nathan said

    Jeff
    I think you should remove this text from your original post:
    “Before you watch the video Figure 1 is a map of the Wilkins ice shelf which apparently is about to melt every hot January summer at the south pole.”

    Quite clearly the Wilkins Ice shelf is not going to melt every summer.

  19. Jeff Id said

    #18, Every Antarctic summer we hear about it. I’m just an engineer, the constant hype about 4 or 5 pixels of ice is frustrating and I vented a bit. It’s good for the blood pressure ;)

  20. Nathan said

    Jeff

    You don’t seem to understand the difference between sea ice and an ice shelf. What we have been hearing about is the progressive disintegration of ice shelves that seem to have been in place for thousands of years. The Wilkins is the latest, and the most southerly ice shelf to begin disintegration.

    “I’m just an engineer, the constant hype about 4 or 5 pixels of ice is frustrating and I vented a bit. It’s good for the blood pressure ”
    So why don’t you do some research and think before you post? You have completely missed the context of these ice shelf collapses. It’s kind of like, as an engineer, saying that small cracks don’t matter because their small, and ignoring the fact that your building has many small cracks that will eventually bring it down.

  21. pete m said

    Nathan – Little Ice Age. Changes over thousands of years. They link this melting ice shelf solely to global warming caused by humans. Get the frustration yet?

  22. Jeff Id said

    #20, You didn’t read the post carefully. I pointed out the origin of the ice shelves. These are very small areas of ice which can collapse and reform repeatedly and I don’t believe they are the scary harbingers of doom that is advertised.

    People like me actually worry about these things when we see the thousands of news articles but with corrupted science (something which everyone honest about climatology knows) there isn’t anywhere to learn the truth easily. I’m not saying all climatology is bad but it’s full of bad apples in the top echelons doling out money and fame to the ‘correct’ scientists. Now that we can see the variance in the sea ice, I don’t worry so much about an ice shelf.

    There is a detail which is discussed in ice shelves where scientists claim that the breaking off will accelerate the flow of ice behind. I want to see an FEA stress analysis of the ice because in this video, compression and shear of the ice doesn’t seem to slow it’s flow one bit. The stuff crumples and breaks so readily, I’m tempted to call it a Newtonian fluid.

    I suspect pushing back on a glacier is similar to blowing water through a capillary tube – you can’t. The other forces in an ice flow such as ground friction are probably far larger than the back pressure created by a large area of sea ice – which is basically what an ice shelf is. So I say so what if a shelf breaks, let’s get some good time-lapse video, some popcorn and throw a party or something because I bet it’s pretty cool to watch mother nature in action, just don’t worry so much. It happens.

  23. Nathan said

    Jeff
    “I pointed out the origin of the ice shelves. These are very small areas of ice which can collapse and reform repeatedly and I don’t believe they are the scary harbingers of doom that is advertised.”

    No you made up some information about the origin of the ice shelves. You failed to do even a simple check of the literature.
    You thought they should break up regularly… How long does a 250m thick ice shelf take to form? Why are you suprised that everyone is chattering when it does break up? Scientists chatter when volcanoes erupt too. It’s a rare event.

    “People like me actually worry about these things when we see the thousands of news articles but with corrupted science (something which everyone honest about climatology knows) there isn’t anywhere to learn the truth easily. I’m not saying all climatology is bad but it’s full of bad apples in the top echelons doling out money and fame to the ‘correct’ scientists. Now that we can see the variance in the sea ice, I don’t worry so much about an ice shelf.”

    You still don’t seem to understand the difference between sea ice and ice shelf. Despite people explaining it to you and being given links. That sea ice image doesn’t show the shelves – they are part of the ‘browned’ out part of the image.

    “There is a detail which is discussed in ice shelves where scientists claim that the breaking off will accelerate the flow of ice behind. I want to see an FEA stress analysis of the ice because in this video, compression and shear of the ice doesn’t seem to slow it’s flow one bit. The stuff crumples and breaks so readily, I’m tempted to call it a Newtonian fluid.”

    Learn the difference between sea ice and an ice shelf… One is a max of 6 m thick, the other in Antartica can be over 1km thick (and around 250m in Wilkins Sound).

    “I suspect pushing back on a glacier is similar to blowing water through a capillary tube – you can’t. The other forces in an ice flow such as ground friction are probably far larger than the back pressure created by a large area of sea ice – which is basically what an ice shelf is.”

    No. An ice shelf and sea ice are VERY DIFFERENT. This is what you are having difficulty understanding.
    Just go and read Wikipedia Jeff.

    “So I say so what if a shelf breaks, let’s get some good time-lapse video, some popcorn and throw a party or something because I bet it’s pretty cool to watch mother nature in action, just don’t worry so much. It happens.”

    The ESA site has good images of the Wilkins Ice Shelf breaking up. It was exciting to watch. That’s why there was so much chatter about it.
    As to your ‘so what’ claim, you are free to hold your own opinion but it doesn’t seem to be grounded in any understanding.

    http://www.esa.int/esaEO/SEMWZS5DHNF_index_0.html

    That shows the ESA satellite page on the WIlkins Ice Shelf. Do yourself a favour, start reading.

  24. Jeff Id said

    Nathan,

    I will spend some additional time when I get a chance. I’ve read wiki and a few papers others so please don’t misunderstand that point. It still is completely non-frightening at this point but rather is just interesting.

    The thickness of the shelf is actually the reason I believe this is more common than realized. It’s age comes from on land rather than on ocean. I just haven’t looked at the formation rate from the mountains because clearly the ice shelf didn’t form in place. Even if this is a 6000 year event as compared to the quick reference above, that isn’t impossibly uncommon that we would see it in natural circumstances. Consider some of the volcanic events are on that timescale as well.

    The main reason we hear about it is not because of it’s amazing size but rather because they want to attribute it to not just warming but Anthropogenic warming. My own belief is that this probably happens more often than people think even without a miniscule 0.8C of possible warming in the last 150 years.

    If the shelf is so stiff from its thickness, will the glacier slide faster as they claim? It makes one wonder how fast will the bridge be rebuilt? 200 years, 500 years? How old would it appear to be after it slides back in place if we didn’t realize it had just broken up? Wouldn’t that change perspective quite a bit? The issue is politicized like all AGW, all I have is questions and very little fear of this globally tiny piece of ice.

  25. George said

    1) I thought the point Jeff Id’s about Antarctic sea ice visual demo was to refute the canard that sea ice is in great decline. Worry-Warmers generally conflate instances of melting of any sea ice, glacier edges falling into the sea and ice melt in unattended glasses of ice tea as evidence of a Sudden New Trend.

    2) “Are you seriously suggesting the Wilkins Ice shelf is less than one hundred years old?”

    Nathan’s rather obsessive attack on Jeff’s offhand remark about the Wilkins Shelf misses the gist of Jeff’s piece which was clearly directed more at Worry-Warmer ice-melt-conflation tendencies.

    I infer that Jeff said that the seasonal rise and fall of sea ice in that same area is evident in the photos and that photos further indicate the edge of the shelf itself may have grown and declined as well. Whether the core of the ice mass is 6,000 or 100,000 years is not at issue. I hope Nathan wasn’t seriously arguing that the Wilkins Ice shelf is itself totally unchanged for the last six to 10 thousand years? (Harrumph, eye roll and heavy sigh).

    3) The observation that the Wilkins Shelf contains ice formed thousands of years ago was apparently offered as an implied proof that any and all melting is sudden and novel. Given that (1) the core of many of the world’s largest surviving ice shelf masses almost certainly date to the last ice age and that (2) those masses have steadily declined since that time, then the burden on worry-warmers when trying to use melt as evidence of AGW is to distinguish any current warming trend from one that has been underway for 10,000 years.

  26. Nathan said

    George

    No I am not saying it was unchanged.

    Obsessive attack? Don’t be so melodramatic.

    “Given that (1) the core of many of the world’s largest surviving ice shelf masses almost certainly date to the last ice age and that (2) those masses have steadily declined since that time, then the burden on worry-warmers when trying to use melt as evidence of AGW is to distinguish any current warming trend from one that has been underway for 10,000 years.”
    There has been no warming trend for 10000 years. That is something you made up.

    Jeff.

    “It’s age comes from on land rather than on ocean.”

    No, an Ice Shelf is defined as being on water. Hence the name ‘shelf’, not ‘sheet’.

    “If the shelf is so stiff from its thickness, will the glacier slide faster as they claim? ”
    The ice shelf is connected to the glacier. Basically an Ice shelf (around Antarctica anyway) is a continuation of the glacier that feeds it over water. As ice is more bouyant than water, the ice shelf lifts as it goes over water, this will impede the flow of the glacier behind it.

  27. Jeff Id said

    Nathan,

    You apparently assume I am an idiot. I find your reply offensive in it’s simplicity. My own background in stress/strain calculation includes a wide variety of test and modeling methods and these bastards would have to pay me very well to do it for them, does yours? While I’m truthfully humble in my study, your assumption of superiority is moronic. I’ve got no idea of your background but I’m quite certain that I understand the stresses in an ice sheet well beyond your own.

    Welcome back to the Air Vent, Big Dog.

  28. Jeff Id said

    Ice shelves form on land and glacier out over the water. Dating is likely from layer measurement.

  29. Nathan said

    Jeff
    Quit being so precious.

    You have repeatedly confused sea ice with ice shelf throughout this post, so I assumed you had no idea what you were talking about.
    Here are some choice comments:
    “Before you watch the video Figure 1 is a map of the Wilkins ice shelf which apparently is about to melt every hot January summer at the south pole.” – completely wrong.

    “Its difficult to imagine after watching this video that this ice shelf hasn’t collapsed (or whatever it’s called) and re-formed in the last several hundred years, more than once.” – The video shows sea ice, the shelf is browned out.

    ” How is it possible this shelf lasted as long as they think in these sea ice conditions? You can see the melt and reformation of so much ice, do you think it’s possible the sea ice was mis-dated due to flow from the older ice in the mountains? ” – the shelf is very thick, around 250m. Yet again, you didn’t actually try and find out the detail.

    As to your last comment:
    “Ice shelves form on land and glacier out over the water. Dating is likely from layer measurement.”
    Ice sheets form on land and become Ice Shelves when they move over water. Dating could be from layer measurements but is also from isotope dating of sediments entrained in the ice.

  30. Jeff Id said

    Nathan, you sound like TCO..

  31. Jeff Id said

    #29 Nathan, your last point above is confirmation of my own thoughts. Whether isotopes are measured or penguin farts doesn’t matter, the layers are likely the dating method. The layers don’t indicate where the ice was formed only when, you need to separate these issues.

    Read the post again and really think– do I know if an ice shelf comes from a glacier. You’ve wasted my time too much already, I enjoy thoughtful criticism and hate liars – sincerely. Do you get me Nathan? If you lie to me about your thoughts, you won’t post here. Be honest and no problem, otherwise — you will be the first and only poster here assigned to the cialis bucket.

  32. Nathan said

    Jeff
    You’re all bluster and zero substance. What is all this about lying? What on Earth is wrong with you? You need to check your facts and forget the stupid conspiracy theories. Give up your cold-war warrior bravado as it’s pointless.
    I won’t bother posting here anymore.

  33. Jeff Id said

    That’s fine Nathan, your exaggeration of what you were reading was driving me nuts anyway.

  34. Jeff Id said

    Just to point out to others Nathans dishonesty.

    I wrote,
    “Before you watch the video Figure 1 is a map of the Wilkins ice shelf which apparently is about to melt every hot January summer at the south pole.”

    in reference to the news articles linked above. These have been coming in reference to Wilkins ice shelf for years.

    I wrote.
    ““Its difficult to imagine after watching this video that this ice shelf hasn’t collapsed (or whatever it’s called) and re-formed in the last several hundred years, more than once.”

    Nathan replied = The video shows sea ice, the shelf is browned out.

    But in reply to another comment I put this in #5 prior to Nathan’s visit–The video shows sea ice, the shelf is browned out.

    Here’s the exchange in #23

    My reasonable comment – “I pointed out the origin of the ice shelves. These are very small areas of ice which can collapse and reform repeatedly and I don’t believe they are the scary harbingers of doom that is advertised.”

    Nathan pretending something which didn’t happen – No you made up some information about the origin of the ice shelves

    My reasonable comment – “People like me actually worry about these things when we see the thousands of news articles but with corrupted science (something which everyone honest about climatology knows) there isn’t anywhere to learn the truth easily. I’m not saying all climatology is bad but it’s full of bad apples in the top echelons doling out money and fame to the ‘correct’ scientists. Now that we can see the variance in the sea ice, I don’t worry so much about an ice shelf.”

    Nathan’s idiotic reply reexplaining that the shelves are browned out as I stated in 5 along with false accusations about literature- You still don’t seem to understand the difference between sea ice and ice shelf. Despite people explaining it to you and being given links. That sea ice image doesn’t show the shelves – they are part of the ‘browned’ out part of the image.

    Now to the insanity of the attack in 23 I replied like this

    I will spend some additional time when I get a chance. I’ve read wiki and a few papers others so please don’t misunderstand that point. It still is completely non-frightening at this point but rather is just interesting.

    The thickness of the shelf is actually the reason I believe this is more common than realized. It’s age comes from on land rather than on ocean. I just haven’t looked at the formation rate from the mountains because clearly the ice shelf didn’t form in place. Even if this is a 6000 year event as compared to the quick reference above, that isn’t impossibly uncommon that we would see it in natural circumstances. Consider some of the volcanic events are on that timescale as well.

    To which Dr. Nathan comes back like this.

    No, an Ice Shelf is defined as being on water. Hence the name ’shelf’, not ’sheet’.

    He then follows up with this
    You have repeatedly confused sea ice with ice shelf throughout this post, so I assumed you had no idea what you were talking about.

    I’ll stop there because he’s pissed me off at this point. There has been no confusion on this issue anywhere Nathan. I can only assume that your refusal to listen to my words is a blogland politically motivated lie.

  35. Harry Eagar said

    I for one am glad that Antarctic ice melts at the edges, otherwise the girls wouldn’t wear such skimpy bikinis at Copacabana beach.

  36. AEGeneral said

    Even if it’s 6,000 years old, I still ask the question: “So what was it before that?”

    A blink of an eye compared to 4,500,000,000 years.

  37. Nathan said

    Jeff
    You are a phony
    Here is where you confused sea ice and ice shelves.

    “There is a detail which is discussed in ice shelves where scientists claim that the breaking off will accelerate the flow of ice behind. I want to see an FEA stress analysis of the ice because in this video, compression and shear of the ice doesn’t seem to slow it’s flow one bit. The stuff crumples and breaks so readily, I’m tempted to call it a Newtonian fluid.”
    The implication here is that because sea ice crumples and moves readily so does and ice sheet.

    “Now that we can see the variance in the sea ice, I don’t worry so much about an ice shelf.”
    Same implication

    “Its difficult to imagine after watching this video that this ice shelf hasn’t collapsed (or whatever it’s called) and re-formed in the last several hundred years, more than once.”
    Same implication

    “Before you watch the video Figure 1 is a map of the Wilkins ice shelf which apparently is about to melt every hot January summer at the south pole.”
    Same implication

    “I suspect pushing back on a glacier is similar to blowing water through a capillary tube – you can’t. The other forces in an ice flow such as ground friction are probably far larger than the back pressure created by a large area of sea ice – which is basically what an ice shelf is.”
    Same implication.

    An Ice Shelf is not a large area of Sea Ice.

  38. Jeff Id said

    Nathan, are you blind? I’ve told you several times I know what an ice shelf is. How complex is that to grasp.

    “There is a detail which is discussed in ice shelves where scientists claim that the breaking off will accelerate the flow of ice behind.”

    FROM BEHIND, I wonder what that refers to.

    Then I make a smart assed comment about the news articles we’re bombarded with (I even included links in the article) and you insist on misinterpreting it.

    The other discussion has to do with how much back pressure an ice shelf puts on the glaicer forming it. I’m nowhere near as certain as the scientists that the glacier will accelerate severely but am just wondering on line. You want to second guess everything in the dumbest way possible for some weird reason. An ice shelf floats on the ‘sea’ it floats because it’s ice and it’s on the ocean. Besides different salinity it’s basically sea ice, which is why I said ‘basically’ instead of IS.

    It’s plainly visible to see that I understan a friggin’ ice shelf, right above. Why you have the need to feel superior on this idiotic point is beyond me. Perhaps a psychiatrist is in order.

    Be honest Nathan or go away.

  39. From the melt patterns, it looks to me like there’s volcanic activity under the Ross Sea.

    Also, interesting that the warmer water travelling south from Cape Horn hits the Wilkins Shelf side, but not the other side of the peninsula which actually accumulates sea ice (and ice shelves too). Now, remembering Svensmark, we have a situation where Antarctica is cooling but the Peninsula flank is open to water that has been warming. This causes a double effect at the Wilkins shelf area: locally, slightly warmer = slightly more snow therefore slightly more glacier pressure pushing Wilkins out to sea; but also a warmer sea to bite off the emerging shelf a bit quicker. Could easily produce more activity than folk remember from 30 years ago when situations were reversed.

  40. Jeff, I don’t know if Nathan is an old adversary or if this is his first thread. His blindness of your awareness is tiresome but he may be aware of sources you ought to know. This website says: The collapse of the Larsen Ice Shelf was the largest single disintegration event in 30 years of ice shelf monitoring (yellow section on map below). Preliminary studies of sediment cores suggest that it may have been this ice shelf’s first collapse in 12,000 years.

    And here’s NASA Goddard which says two new NASA-funded studies show that ice shelves — platforms of ice that extend from the shore into the ocean — act as buttresses, or braking systems for glaciers that flow into them.

    Now I’ve seen a reason for 30 quiet years, you’re probably more of an expert on tensions (and with imagination) than most seasoned polar scientists, and we both know the real climate situation. Are the scientists really playing fast and loose with descriptions, hungry for grants? or what? or are they just unobservant? or are there factors that WE have not spotted?

    Over to you.

  41. uh, forgot to close the italics at the end of the NASA paragraph.

  42. Jeff Id said

    #40, I’ve got no idea who he is. I do realize the sediment was used for dating, my problem is that the ice actually forms in the mountains and slides over the sea. If the shelf breaks up and a new one slides into place at a couple km/yr, you would have entirely new 12000 year old ice shelf after 50 or 100 years. How can they tell the difference? I asked Dr. Meier that question at WUWT but didn’t receive an answer.

    I think Nathan picked up on that point I was making and still came back with more bs. That’s and the obvious nature of what I wrote are what makes me think hes dishonest in his criticism.

  43. Nathan said

    Jeff

    “If the shelf breaks up and a new one slides into place at a couple km/yr, you would have entirely new 12000 year old ice shelf after 50 or 100 years. How can they tell the difference?”

    I can’t believe you can’t see the stupidity of this statement. How could the ice sheet ‘age’ for 12000 years if the ice shelf holding it back breaks up every 50 to 100 years? Even if it broke up 50 years ago, it would still mean that the ice shelf would have had to have existed for 12 000 years prior to the break up. Also note that the dating is not based on one date. There will be dates all along the ice shelf, which more than likely will show a range from 12000 years to present (in that example). The range of dates demonstrates that there has been continuity in the life of the ie shelf.

    I like how you decided the quotes of yours I provided are “bs”.

  44. Nathan said

    Jeff

    Note the range of dates:
    http://my.hamilton.edu/news/exp/Antarctica/2006/Geology_2003v31no9.pdf

  45. Jeff Id said

    Nathan, the quotes regarding melting every few years were a clear reference to the news articles linked above or haven’t you noticed the same story happens every year?

    The rest of us have.

    “Even if it broke up 50 years ago, it would still mean that the ice shelf would have had to have existed for 12 000 years prior to the break up.”

    Yes,Nathan, but it would exist for 12000 years on land —- where it’s formed. There are a half dozen of my own references to that ‘obvious’ fact in the article and statements by myself above. Stop being so deliberately dense about it. My question to Dr.Meier was how do you date the ice ‘shelf’ rather than the ‘ice in the shelf’ after it slides back in place. – They are different.

    In the case of the Wilkins shelf, the runout distance is pretty small before it hits land again. The thing very well could be 5000 years old but there are several articles which suggest it runs on a shorter period than that – despite really the old ice.

    The Larsen shelf you reference in your link has a long runout distance into peninsula sheltered waters. This shelf couldn’t grow to that size on the other side of the peninsula because of the circumpolar currents.

    Thanks for the link.

  46. Richard said

    The Point is that Indiana, Illinois and Ohio are so flat because they were under Ice 10,000 years ago. They melted and retreated long before coal plants or cars. So yes, there has been a “warming” and melting for 10,000 years. Who are the worry warmers to decide what is the exact temperature the earth should stay?

  47. Brian Dodge said

    Jeff Id says
    “There is a detail which is discussed in ice shelves where scientists claim that the breaking off will accelerate the flow of ice behind. I want to see an FEA stress analysis of the ice because in this video, compression and shear of the ice doesn’t seem to slow it’s flow one bit. The stuff crumples and breaks so readily, I’m tempted to call it a Newtonian fluid.

    I suspect pushing back on a glacier is similar to blowing water through a capillary tube – you can’t. The other forces in an ice flow such as ground friction are probably far larger than the back pressure created by a large area of sea ice – which is basically what an ice shelf is.”

    http://www.agu.org/sci_soc/prrl/prrl0433.html
    “Almost immediately after the 2002 Larsen B ice shelf collapse, researchers observed nearby glaciers flowing up to eight times faster than they did prior to the break-up. The speed-up also caused glacier elevations to drop, lowering them by up to 38 meters [125 feet] in six months.”

    So you would more readily believe a computer model FEA than real observations? &;>)

    Ice rafted debris is deposited at higher rates in areas where the edge of the ice shelf is calving icebergs and to the seaward of this zone as the icebergs melt- [see Antarctic Glacial History from Analyses of Ice-Rafted Deposits in Marine Sediments: New Model and Initial Tests Watkins et. al. Science 8 November 1974 186: 533-536 [DOI: 10.1126/science.186.4163.533]. In addition, remains of diatoms and other sunlight dependent critters get deposited where there is seasonally open water, but not beneath thick ice shelves.
    “These important climate records also reveal the mid-Holocene warm period (ca 9000–6700 years BP) when subpolar diatoms appear in the sediment record (Leventer et al. 2002).”[Climate change and the marine ecosystem of the western Antarctic Peninsula, Clarke et al, Transactions of the Royal Society B 29 January 2007 vol. 362 no. 1477 149-166]
    Bottom sediment cores which lack diatoms and show low rates of ice rafted debris deposition indicate that the Wilkins, Larsen, and other ice shelves have been stable features for ~6000 years, being fed by glacial ice sheet at the landward side and calving glaciers at the seaward limits. Even though the ice which was above a particular spot a few years ago isn’t the same ice that was there a thousand years ago, the ice shelf has been there until recently; this year for Wilkins, 2002 for Larsen B, and so on. “These records are also important in indicating clearly that despite a long history of variability, the current rate of atmospheric warming is unprecedented in the recent geological record (Domack et al. 2005a).” [ibid]

  48. Jeff Id said

    I don’t disagree at all Brian. The Larsen shelf is well protected from circumpolar currents and is probably quite old compared to the Wilkins shelf – just guessing. I do doubt the bottom sediment core conclusions as do some researchers apparently. My question to Dr. Meier was, how fast would the Wilkins shelf replace itself if the ice sheet was out of the picture. Unfortunately, he didn’t answer.

  49. David said

    Wow. I was rading the exchange between Nathan and Jeff. nathatn just refuses to take into account that ALOT of the chatter about melting ice is bogus. It was a good exchange until he claimed a volcano erupting is a rare event, he lost credibility then. An erupting volcano is not a rare event, it is quite common actually, the same with melting ice and the reformation of ice at the poles.
    Anyway, great video and site.

  50. Otter said

    ‘There has been no warming trend for 10000 years. That is something you made up.’~ nathan

    Interesting. According to that statement, we should still be under a mile of ice. No warming trend over the past 10,000 years? How very odd.

  51. george said

    it was as shit as my arse.

  52. george said

    it was as shit as my backside!

  53. george said

    I am gay

  54. george said

    i watch gay porn

  55. george said

    I wank over my dog

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