Another one bites the dust

Or nearly does, at least. It seems that the Wilkins ice shelf is hanging by a thread and bits are falling off. You’ll have to forgive me for being late with this news, as I’ve been off in the Real World for a week or so, with only intermittent internet connections. The paper world seems to have ignored the story, which will have annoyed BAS’s PR department. But there isn’t all that much to it.

The Antarctic peninsula is warming, and we know that because we have thermometers that tell us so. Having ice shelves break off every now and again provides good visual appeal.

As BAS says in 1993 [DV] predicted that the northern part of Wilkins Ice Shelf was likely to be lost within 30 years if climate warming on the Peninsula were to continue at the same rate and, yes, the prediction has come true. There seems to be some attempt to spin this as happening much faster than expected… over at CSM the same DV is saying we got the time scales completely wrong. We were saying 30 years at that time, and now it’s happened within 15. To my mind, if you way “within 30″ and it happens in 15, you got it right.

So I guess the problem is that there isn’t too much new here. Its another ice shelf (and who can tell them apart) falling apart, pretty well as expected, and it isn’t going to raise sea level. Errrm, yes. It is of course entirely consistent with global warming, but not a very good measure of it. A better measure, Antarctic wide, would probably be the sea ice extent, and that isn’t being very obliging at the moment.

Comments

  1. #1 kent
    2008/03/30

    I used Google earth ( the free version) and you can see where previous collapses have occured.You can also see where the collapsed ice has frozen in place. It is interesting that what is called a thread is actually 6 kilometers wide. All that ice is being frozen in place and might even help in increasing the sea ice extent.

  2. #2 Hank Roberts
    2008/03/31

    Kent, aren’t the blocks from the collapse “being frozen in place” only for the winter? Why would this change the sea ice extent, since this ice was already floating?

  3. #3 Ian
    2008/03/31

    Hank, I think Kent means that the collapsed/cleaved ice will separate a bit from the remaining shelf, and the water in between will freeze. If this happens, then there’s a (very small) increase in extent. But as you say, it may just delay further melting/drifting until the next summer.

  4. #4 guthrie
    2008/03/31

    Over at the SCotsman, I have a denialist claiming this collapse is due to volcanoes, despite the map of Antarctic volcanoes they supplied showing none anywhere near it….

    [Ah well, that will be why its all black with tephra then -W]

  5. #5 Gareth
    2008/03/31

    Meanwhile, ‘oop North the ice has begun to melt and the anomaly is increasing rapidly – almost back to the levels seen this time last year. The bet’s still 50/50, I reckon, but the next few months will be interesting.

    [Still up for grabs; I prefer http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.jpg -W]

  6. #6 Steve Bloom
    2008/03/31

    William, is it clear how good of a temp proxy the Antarctic sea ice is (not that the ice shelves are for anything but the AP)?

    [Well, T is one influence, and an important one. No-one seems to have similar doubts about the arctic ice -W]

  7. #7 JCH
    2008/03/31

    Gareth – don’t start counting your eggs before they’ve melted.

  8. #8 Nin
    2008/03/31

    Perhaps if the BBC reporter were to have flown out from Terminal 5 it would have made front page??

    It’s interesting to note that the tropics are getting wetter too…. Interconnected? Maybe. A lot more attention should be paid to the effects of polar temperature on the tropical moisture budget which is going to have tremendous teleconnective implications for climate elsewhere. Thus far it’s been greatly under-rated.

  9. #9 Steve Bloom
    2008/03/31

    Re the Arctic sea ice, we can’t just talk temp overall, but rather air temp, ocean temp, and temp change from cloud cover or the lack thereof, all of which seem to have been pulling in the same direction lately. I suppose the same distinctions (plus other non-temp factors of course) apply to the Antarctic ice, but have they been pulling together in the same way?

  10. #10 Gareth
    2008/04/01

    Up for grabs indeed. Have you got a cut-off date for bet increases?

    [Its at my discretion. What are you proposing? -W]

  11. #11 Gareth
    2008/04/01

    Well, minimum should be in September, but last year looked remarkable from June onwards. What would you be comfortable with?

    [I don’t know. What are you offering? -W]

  12. #12 Hank Roberts
    2008/04/01

    Is there any data collected that might clarify whether there’s increased meltwater coming from under the glaciers? Salinity levels at the outlets? Salinity at the surface where sea ice is forming?

    Not many ARGO devices at the ice edge!

  13. #13 Gaelan Clark
    2008/04/01

    Curious, isn’t this what ice shelves do?….calve into the ocean. What are the actual dynamics of this ice shelf?–How long has it been in its current state, how much of it calves off in any given year, what extent of this particular shelf is over sea floor, how fast does it move towards the sea?(and on and on)–I don’t see much talk towards these natural phenomenon.
    What of the inland ice extent in Antarctica? By all accounts growing and growing. And, how many thermometers are in Anarctica? And where are they located? Because, and again curiously, the satellites show overall cooling. Do they not?

    [They do not. See, for example, http://en.wikipedia.org/wiki/Image:Antarctic_Temperature_Trend_1981-2007.jpg -W]

  14. #14 Alan Woods
    2008/04/01

    William, that Antarctic Temperature Trend image you link to has a level of uncertainty of 2-3 degrees celsius. Given that would equal the greatest increases, are the satellites much use for this sort of thing?

    [I don’t think that 2-3 oC is correct. Its cut-n-pasted from the NASA site the image comes from, but it doesn’t reflect the likely level of error in the trends, which is much smaller. My main point was that the previous commenter was wrong; the BAS site has thermometer measurements such as they are -W]

  15. #15 Gareth
    2008/04/02

    Well, the longer you leave the cut-off date, the more the current season melt affects the final bet. If I (think) I see excessive melt in (say) June, I might up my bet. You might want to say that betting stops when the ice is under starter’s orders, which is probably about now.

    [I’m happy to consider offers. Its not looking bad enough yet that I’m definitely cutting off -W]

  16. #16 Gaelan Clark
    2008/04/02

    William, Thank you for your time, most importantly–thank you for your contributions to climate science.
    I want to understand your point better–that being that Antarctic temperatures have not been cooling within the last decade.
    –a 12 Feb 2008 Real Climate post–“Antarctica is Cold? Yeah, We Knew That”–The group admits to Antarctic coldness relative to recent trends.
    –http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=700890220000&data_set=0&num_neighbors=1 –This link is a Surface Temperature Analysis, interesting trend from ~1990 to present–temperatures are getting colder.

    [You can’t just pick one station! Thats called cherry picking. See for example http://www.nerc-bas.ac.uk/public/icd/gjma/trends2006.col.pdf -W]

    –And, ( http://data.giss.nasa.gov/cgi-bin/gistemp/do_nmap.py?year_last=2007&month_last=12&sat=4&sst=1&type=anoms&mean_gen=0112&year1=1988&year2=2007&base1=1968&base2=1987&radius=1200&pol=reg )–take out the years 1979-1987, and what do we see??
    Is this a trend, or an anomaly?

    [Why are you taking out arbitrary years? -W]

    BTW, your link for the surface temperature from 1979-2007 shows large areas where we all know there are no thermometers—how exactly do you derive the temperature where there is no thermometer??(This is going to be good, I can feel it in my cold-weather prone knee now.)
    –If you have a link to the satellite data, please provide, I would really like to see the last decade of temps that you say have been showing warming.

    [Sorry, I don’t know what you mean. Which link. Do you mean the satellite T pic? Follow it back to the NASA source -W]

  17. #17 Gaelan Clark
    2008/04/03

    NO NEED TO POST THIS COMMENT–Just a note to the owner of this blog–whom, I have much respect for.
    William,
    Thank you for your response.
    Honestly, I have no idea where to find all of the information. In my quest for information I stumble over bits and bits and try to extrapolate, for myself, the bigger picture. I intend not to cherry pick because I don’t know where the cherry tree is, if that makes sense.
    I am concerned about the “one-sided”-ness of the AGW/Climate Change debate/issue. Even in the IPCC literature there is stated that theirs is not the motive to push one agenda, and that they will provide all infomration relevant to the issues being discussed, yet…it is one-sided–towards man-made causes only.
    I have come to respect what climate scientist do, I am a historian–not by trade but by choice in school–so I am aware of the peculiarities of trying to attribute timeframes and events of the distant past to specific times of actual occurence.
    I am compelled to find out more for myself because it seems that there is so much “miss-information” being propogated by for instance–Al Gore, whom many people hold to a very high regard and will listen and follow verbatim. The movie, An Inconvienent Truth, is rife with inacurracy and out-right lies, yet it is given an Oscar for Documentary and Al Gore is given a Nobel Peace Prize.—For what???

    [Please don’t mix up Gore and IPCC. They are very different. I’ve been critical of AIT – see for example http://scienceblogs.com/stoat/2007/10/the_boring_truth.php and links – but I don’t agree its rife with out-right lies (examples?) -W]

    It is from this platform that a very real scare is launched, unfairly so and without merit.
    When people say “the science is settled”, how does that make you feel about what you, and others, are doing?

    [The science is settled is usually said only by skeptics as a strawman to attack. Which quote are you thinking of? -W]

    If I were a climate scientist, I would be very, very alarmed at the likes of Al Gore, and the flock who cannot/will not accept that there is/could be natural variations that explain everything that is happening with the climate.

    [You pick a poor point to fight on. Just about no-one thinks that natural var can explain current changes. You should swap over to “but will it be a problem?” -W]

    As for the ice shelf that this post is about, I may have missed your point as being sarcastic about using it as an example of Antarctic and Global Warming, or you may be trying to bring attention to the Antarctic and Global Warming–I just can’t follow. But, I will tell you this much, it was news all over the pages that I scan–MSNBC, CNN, and other news portals.

    [Well, ice shelves are photogenic. Pandas aren’t really news either but they are cute -W]

    I will not waste your time any more. Thank you again, for taking the time to reply to my previous posts, and I hope that you understand there are civil people who will disagree with AGW (not Climate Change), unfortunately the AGW camp seems to be full of vitriol and hatred at anyone claiming the science not being settled.
    Best Regards,
    Gaelan

    [If the science was settled, what would climate scientists do? -W]

  18. #18 Gaelan Clark
    2008/04/03

    William,
    I did not group the IPCC and Al Gore together, in fact they were seperated by an independent thought that I shared with you.
    I will start with one reference to Al Gore’s outright lies—Lonnie Thompson’s Thermometer…….
    Can you tell me about Lonnie Thompson’s Thermometer?
    If it is not a lie to state things as fact, as does Al Gore, with specific reference to his good friend Lonnie Thompson’s thermometer, then I guess I do not know what a lie is.—as defined at Merriam Webster–1 : to make an untrue statement with intent to deceive
    2 : to create a false or misleading impression

    [It seemed very mixed to me. As to LTT, err, not sure what you mean. There was something about which Hockey stick got displayed, but as far as I know that was an error, rather than a deliberate attempt to deceive. Unless you have reason to believe otherwise? -W]

  19. #19 Gaelan Clark
    2008/04/03

    William,
    LTT is a precipitation proxy(as stated in IPCC literature), not temp. If Lonnie Thompson was such a good friend of Al Gore, wouldn’t/shouldn’t they have talked about this?
    William, I really do appreciate your time, and this will be my last post on this subject as I do not want to antagonize you, nor any other of your guests on this site. It is just a shame how much the information gets distorted, whether an outright lie, or just ignorant baffoonery of the information.—As was the case of attributing the entire Hockey Stick graph on AIT to LT–when the last part of it was an instrumental record from MBH(??)–this is an attempt to deceive AND to creat a false or misleading impression that would only inure to the benefit of AIT and the position of AGW that is its very premise.

    [I don’t believe you. First of all, can you point to something describing the problem a bit more clearly? And secondly, since I vaguely remember this, I simply don’t believe there was any deliberate attempt to deceive. If you have some special knowledge to show otherwise, do please produce it -W]

  20. #20 guthrie
    2008/04/03

    It is silly to look only at Gore. Why nibble away at acknowledged errors, when you can strike the edifice down in one blow by proving that CO2 is not a greenhouse gas, that the IPCC are a communist plot to take over the world?

    But, more seriously, people get far too hung up on the media message, which is usually outrageously sensational, and ignore the science. Gaelen- do you want to start addressing the science?

  21. #21 cce
    2008/04/04

    Big day for the “thermometer.” Hockey Stick on top, Thompson Thermometer on bottom.

    http://cce.890m.com/thompson-mann-rotated.jpg

    This is from a paper by Thompson. Gore (or more accurately whoever did the graphics for AIT) used the Hockey Stick instead of the Thermometer. The point was that the “thermometer” supports the Hockey Stick, which it obviously does.

    And if it is was a measure of precipitation only, and not temperature, all those glaciers should be bursting with new ice. Instead, they’re dwindling to nothing.

    [Ah, I think I begin to understand where our new skeptic is coming from -W]

  22. #22 Gaelan Clark
    2008/04/04

    William, Sorry for hijacking this thread with Al Gore–I have more to say towards your post, but respectfully will not–and I know that I am limited in my understanding of ALL issues.
    –I keep an open mind towards any developments in climate science and try not to get in the way of the people who do the actual work. Like I mentioned before, I am an Historian by schooling, so I have a good understanding of how to look things up and cross reference–all I am trying to do is develop a better understanding of a very serious issue.
    Sorry Guthrie, I can only parrot information, I cannot discuss the intricacies of climate science from first hand, so no, I cannot with any “degree” discuss the science. But am willing to listen(read).
    —And, William, science is about skepticism, is it not?

    [Of course. But don’t get lingusitically confused by skeptic as-in “all good scientists are skeptics” which is true; as opposed to the label “skeptic” which is simply used to label the don’t-believe-in-GW side -W]

  23. #23 David B. Benson
    2008/04/04

    Gaelan Clark — I recommend reading “The Discovery of Global Warming”, linked here:

    http://www.aip.org/history/climate/index.html

    It was written by an historian.

  24. #24 guthrie
    2008/04/05

    I second reading “The discovery of global warming”. I should have suggested it myself. It is a very good place to start.

  25. #25 Gareth
    2008/04/06

    Jeff Masters has an interesting post on this year’s prospects.

  26. #26 Eli Rabett
    2008/04/06

    Gaelan, science is about informed skepticism not bullheaded denial.

  27. #27 Matt
    2008/04/08

    A lot more attention should be paid to the effects of polar temperature on the tropical moisture budget which is going to have tremendous teleconnective implications for climate elsewhere.

    [BAS will be delighted to hear you say it. There is some evidence, though, that the “information flow” follows the “energy flow”, which is to say equator to pole, which is to say that the teleconnections tend to be, causually, equator to pole -W]

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