Since people are wanting to talk about the latest events on the Antarctic Peninsula, this is a post for that discussion.
The imagery from ESA (animation here) tells the recent story quite clearly – the last sliver of ice between the main Wilkins ice shelf and Charcot Island is currently collapsing in a very interesting way (from a materials science point of view). For some of the history of the collapse, see our previous post. This is the tenth major ice shelf to collapse in recent times.
Maybe we can get some updates and discussion of potential implications from the people working on this in the comments….?
Lawrence Brown Says (13 April 2009 at 3:51 PM):
“I had nothing to do with the preemptive strike on Iraq. :>)”
I’m trying really hard to avoid getting further into politics, so I would just suggest investing in a dictionary & some English lessons in addition to the ones in the fundamentals of arithmetic. Then you can look up the meaning of the word “preemptive”.
“5. And as a layman, how would I write about the Wilkins split-off as evidence of (A)GW in a 400 word letter to a local/regional newspaper? (Or is the word count too short for something of such complexity?)”
When you lose one ice shelf, it can be considered an accident.
When you lose 10, it’s carelessness.^W AGW.
“I’m starting to feel a little like Henry Fonda in “Twelve Angry Men”.”
With the rather important difference that Henry Fonda’s character was asking for evidence. Here we’re asking you.
“so I would just suggest investing in a dictionary & some English lessons in addition to the ones in the fundamentals of arithmetic.”
That’s a tall order,James. Rather than do that, I’m going to bask in ignorance and be grateful that science is taking the upper hand after the preeminence of dogma in our government over past two terms. It isn’t easy to leave ideology out of the picture, since the original post that I responded to was the use of a leftist takeover by an earlier poster.
A note of appreciation to Gavin and many others on this site.
Keeping up with the site’s multiple threads is difficult and time consuming, but worthwhile. I am a relatively uninformed ex-physicist who accepted the IPCC reports without much thought until two months ago. This site has informed me greatly on the controversies which still rage in some newspapers, the Rush Limbaugh travesty, and other anti-AGW sources. Lots of material here to write about for my Rico (Colorado) paper. And I am much better equipped to respond to colleagues and friends who have swallowed some of the anti-AGW garbage.
I don’t have to be a “climate scientist expert” to understand that one side here has (almost) all the facts and the other side most of the rhetoric! I am encouraged to see that the facts seem to be winning!
Again, appreciation.
Burgy
A question on the “Oregon Petition”.
This is somewhat off topic, but the core of this discussion – Wilkins Ice Shelf – seems to now have run out of steam. So I feel it’s OK. (?Moderator)
I’m in England. However, the petition is widely quoted here as evidence of no climate change.
There is a lot on the web for and against the petition, but it is all about the second paragraph, that deals with climate change. I am aware of these arguments.
However, the first paragraph is a rejection of the Kyoto Protocol – a petition to the US government not to sign up to Kyoto. This is the first part of the petition. I have not seen anything about this first paragraph. By being set first, can I assume that this is the intended core of the petition?
Can I then reasonably assume that many of those who signed were perhaps more concerned with not signing up to Kyoto – rather than the second paragraph which was about no catastrophic heating of the Earth’s atmosphere? Were people, essentially, signing up to a political position rather than an environmental one?
Theo H
Theo, the Oregon Petition is not very well-respected.
Here is one view of the matter.
Theo,
The entire point of the Oregon Petition (much like the Inhofe 400 and others) is to create the impression of reasonable debate, and thus to delay action against climate change. To many people, the idea that 31,000 scientists disagree with something is quite impressive, regardless of who those signatories really were, or more importantly, if anything of scientific quality really backs them up. Really, it’s an appeal to American’s democratic sensibility.
I have taken the time to sample 60 names (choosing 54 of the alleged phD’s on the list) at this link, and in the process I have found no one with qualifications or a publication record in climate science. I have found intelligent design researchers, bridge designers, engineers, lots of medical people, smoke alarm makers, deceased people, geologists from world war 2, and many other things. From this, I cannot conclude that OISM represents any reasonable opposition to the consensus that is clearly laid out in the literature, in statements by the National Academies and other scientific organziations, etc.
>> I’m starting to feel a little like Henry Fonda in “Twelve Angry Men”.
More like Walter Brennan in “Support Your Local Sheriff”, where James Garner stymies him simply by putting his finger in the end of his six-gun.
You’ve been shooting blanks (bald unsupported assertions) for some time now.
Theo, the Oregon petition is ***given*** as an example of evidence of no climate change.
However, even if it were genuine, it would not be evidence of that, just evidence that 31,000 people didn’t think it was a problem.
Heck, the monster raving loony party get more votes than that in election. Is this evidence that we’re all monster raving loonies? Or just that there are many people who will vote for them?
And it isn’t genuine. All it is really showing is that something like 31,000 people will sign up to anything.
Mind you, slashdot recently had a story about Ponzi schemes on YouTube getting over 500,000,000 hits. So getting 31,000 votes on this isn’t all that solid either.
@ Chris
#558
Thanks for the post, Chris. You have done some interesting work there. Certainly the hard evidence to demolish the petition. Fact, not supposition.
And thanks to others too.
But I still have a question.
I guess in my earlier post I didn’t want to ask (in UK law, at least) what’s called a “leading question”.
But I will ask it anyhow.
Is the Oregon Petition designed and set up to get the “votes” of the right in US politics, and specifically, Republican “votes”? Especially as Kyoto would tie the US into international treaties – something your previous president seemed reluctant to do.
Would Democrats and independents be likely to sign up to it?
So is it a political document?
Anyway, the petition comes up a lot in op-ed writing and letters to the (local) press in the UK. In letters to the press I think these are people who genuinely believe GW and/or AGW don’t exist. The petition is also being championed by _some_ of the more rightwing newspapers in the UK. In letters to the press, it is a regular appearance. That there are PhDs signing the petition impresses a lot of folks, mostly because they don’t understand how common they are and that having a PhD sometimes doesn’t mean much beyond a very narrow band of some very specific science. (My UK girlfriend did her post-doc stuff at Oregon State University; that meant I spent a lot of time in the Oregon as I was teaching in UK and had long holidays. Thus I know about the wacky sorts of folk who have institutes in remote red-neck towns, as does the OISM. But I love America, BTW).
Sad fact is. The Oregon Petition is doing what, I assume, was expected of it, and it is commonly quoted in the UK. So for OISM, it’s a clear winner.
My brother is one of the 31,000 “scientists”. He is far right. When I try to discuss climatology with him, his canned response is “they just don’t know for sure”.
And he does not qualify as a scientist. He is an engineer who helps design industrial complexes, where CO2 abatement might be considered unwanted overhead.
I lurk here to read and learn. I’ve learned a lot. Keep it up.
And I happen to live in Salem Oregon, and got my undergrad from Oregon State University. (Red neck country)
#528 #530 Timothy Chase
Thanks, that was a great read :)
As far as Alan Millar saying I think I am an expert, as I have stated previously, I know the tiniest fraction of what is knowable (and probably even less). I’m just looking at the evidence that is scientifically well understood and trying to piece the picture together.
That picture tells me we have huge challenges ahead of us that will strain our economy if we don’t diligently address it in rapid fashion.
Thank you for your work on the early Holocene, I personally had not read much about it.
Captcha: Winter recalling
We could lose ice from 100% of the glaciers on the planet instantly and see no change in sea levels. As long as it’s only the top 1mm. But that’s a change over 100% of the extent of the ice on this planet! All I have to do is not tell you about the 1mm depth bit and you’re told 100% of the ice is melted. Just don’t look at the detail.
@Bhutan Havayollari 16 April 2009 at 3:48 AM
But of course it’s not 1 mm, and its not instantly, but about 273mm every year, and it’s increasing.
“How glaciers’ contribution to sea level is computed
Global mass balance data are transformed to sea-level equivalent by first multiplying the ice thickness (meters) lost to melting by the density of ice (about 900 kilograms per cubic meter), to obtain a water equivalent thickness, and then multiplying by the surface area of these “small” glaciers (about 760,000 square kilometers). This provides an annual average mass balance of approximately -0.273 meters for the period 1961 to 2005.” http://nsidc.org/sotc/sea_level.html
See also http://www.grid.unep.ch/glaciers/img/5-9.jpg
So who’s “not telling” the details? The scientists, or the deniers?
Brian, I think Bhutan was saying that only saying half the situation, you can get whatever you want.
Denialists use the small increase in water level as proof that the ice isn’t melting (and mention that glaciers are increasing in extent, again missing out “a very few” from that).
cf the lack of a cooling signal in the upper troposphere. All you have to do is miss out that the errors in the measurement mean you cant tell if there’s a signal or not.
At least that was what *I* meant when I said it.
I’m going to start posting this reference on a regular basis:
Dunning-Kruger Effect
“The Dunning-Kruger effect is an example of cognitive bias in which “people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it”. They therefore suffer an illusory superiority, rating their own ability as above average… “DK: 1) Incompetent individuals tend to overestimate their own level of skill. 2) Incompetent individuals fail to recognize genuine skill in others. 3) Incompetent individuals fail to recognize the extremity of their inadequacy. 4) If they can be trained to substantially improve their own skill level, these individuals can recognize and acknowledge their own previous lack of skill.” — Wikipedia
link: http://en.wikipedia.org/wiki/Dunning-Kruger_effect
IT IS IMPORTANT TO NOTE: Point #4 is why we all keep doing this.
cougar_w
Is there any data on how other Ice shelves are faring this year? Sea Ice extent is increasing rapidly. It seems counterintuitive that the shelves would continue to collapse while ice extent trends look like this.
http://nsidc.org/data/seaice_index/images/s_plot_hires.png
[Response: it’s not counter-intuitive at all if you look at the spatial distribution of sea ice trends. On the west side of the peninsula sea ice is way down. – gavin]
I’ve been scanning the popular press for news reporting on the Wilkins Ice Shelf. Fox News online reprinted a fair Times of London article with a March picture showing the bridge intact.
http://www.foxnews.com/story/0,2933,512715,00.html
There was a section at the bottom of the page –
“PEOPLE WHO READ THIS…
Also read these stories:
Knights Templar Hid the Shroud of Turin, Vatican Says
Scientists Race to Prevent ‘Catastrophic Disaster’ in Space
(scientists race to stop space ‘catastrophe’, space junk invaders)
Navy Chemist May Have Rediscovered ‘Cold Fusion’
Giant ‘Hand’ Reaches Across Space
(massive ‘hand’ reaches across space, hand of god?)
An ‘Embarrassed’ Carrie Underwood Apologizes to Matthew McConaughey Over Sexual Reference in Acceptance Speech”
Reality recapitulating a George Carlin “news” routine.
Hank Roberts (#522): “Would you watch a little movie?”
This is very worthwhile. I learned a lot from it. But — and this is just a nit — I would not call it a “little movie”, since it’s a slide show and lecture by Dr. Gerald North, which lasts an hour and five minutes.
Eric wrote in 568:
Check 267,268 above. The first is a response by me to what was essentially the same question. The second is an update by Ike Solem.
I love your website. I don’t know whether you’ve noticed but this weekend’s edition of The Australian newspaper goes to town with the denialist point of view, using the new book by geologist Ian Plimer – Heaven and Earth: Global Warming – The Missing Science. There is an interview with Plimer here http://www.theaustralian.news.com.au/story/0,25197,25348271-11949,00.html and an article by Greg Roberts throws in Antarctic cooling here http://www.theaustralian.news.com.au/story/0,25197,25349683-601,00.html. All the usual arguments but given the influence The Australian has in the educated Australian middle class it would be great if you offer a response, either letter or article.
John Ransley:
Whatever educated class of Australians The Australian influences, it’s certainly not those educated in science.
Another qualitative view:
End of the ice age process is just a demonstration of one type of tripping point.
When melting of continental ice sheets in Eurasia and North America was complete, a marine based process became dominant in the Arctic. Arctic Ocean is a rather circular feature, limited by the 70th parallel.
Another tripping point will be when the slowly expanding tropical belt meets West-African and NW Australian E-W oriented coasts. Marine based processes will be replaced by quite different continental ones.
Johm Ransley. I did a very quick layman view of why the article should be treated with extreme skepticism in response to someone else’s post of the write-up about that book.
It’s on another thread, but you should have mailed the site owners rather than plop it on a thread since the site owners can make sure that only one copy is made and only one thread to go to for it. What you did either means you don’t get a response or work has been doubled. Neither good news.
http://www.theaustralian.news.com.au/story/0,25197,25349683-601,00.html. All the usual arguments but given the influence The Australian has in the educated Australian middle class it would be great if you offer a response, either letter or article.
What exactly is it that you disagree with in this article?
# John Finn Says:
19 April 2009 at 6:14 AM
What exactly is it that you disagree with in this article?
++++++++++++++++++
Well, the result doesn’t say that GW is wrong or reversing.
(an aside: how is it that data on a fifteen shrinking ice sheets isn’t proof of AGW but one growing area is proof AGW is wrong?)
Antartica isn’t the one station.
Ice depth they are measuring is the one-year-old annual ice. This depends on the WEATHER of that season, not the climate the season is falling under.
Thickening ice requires more moisture to be precipitated out. That only occurs when the air is warmer.
And so on and so forth.
John Ransley:
Harry Clarke covers the interview with Plimer.
The second Australian article, Revealed: Antarctic ice growing, not shrinking, talks about sea ice, ice shelves, and ice sheets as if trends in one sort of ice automatically imply trends in other sorts of ice. The real world is not so simple.
Some confusion here. Extensive melting of Antarctic ice sheets is not required to raise sea level substantially, as there is plenty of easier to melt ice in Greenland. Enough to raise global sea levels by about 6 meters.
True, but cherry-picked. On the whole, over the long run, Antarctica is warming. (See also here .) But much more importantly – AGW will serious consequences even with no significant melting of the East Antarctic ice sheet, and very little melting of the West Antarctic ice sheets. In fact, there is already a continent in the southern hemisphere somewhere which is suffering severe long-term droughts, heat waves, and fire seasons, likely exaberated by AGW.
I tried to google up the supposed comments by Peter Garrett. I tried several variations, and got nothing but the Australian article. Sea level rise of 6m by 2100 is extremely unlikely, whatever it’s source. If Garrett said what the Australian claims he said, he’s wrong. But given the Australian‘s history of misquoting people, I don’t think there’s any reason yet to believe them this time.
…
If the issue is that Antarctic sea ice is expanding (not a big surprise), why confuse the issue with so many paragraphs about ice shelves and ice sheets? Why choose a title that gathers together different sorts of ice in such a clueless fashion?
Given the Australian‘s long record of pretending global warming is either not real, or good for everyone, I think they’re trying to portray the soon to be published BAS findings as a rejection of previous reports that the West Antarctic ice sheet is losing mass, of the recent collapse of the Wilikins ice shelf, and so on. But sea ice is far more subject to short-term variations than ice sheets or ice shelves.
Interested folk may wish to keep an eye on Tim Lambert’s blog, deltoid . He has a long-running series called ‘The Australian’s War on Science’ which has addressed many grossly inaccurate Australian articles in the past.
#568,
“it’s not counter-intuitive at all if you look at the spatial distribution of sea ice trends. On the west side of the peninsula sea ice is way down. – gavin]”
I’ve been mulling over a question lately, as to whether thinner ice is also incorporated in GCM’s??…
http://cat.inist.fr/?aModele=afficheN&cpsidt=3260093
AS to whether they lack this feedback or not? Ice extent is one thing, thinner sea ice has an important heat component as well. With respect to Wilkins, and other ice shelves, it may be all about warmer air not so well factored……
A response to llewelly, Part I of II:
llewelly quoted a misleading article in the Australian:
… then states in 578:
Even earlier data suggested that the “cooling” or “warming” is largely dependent upon the starting and ending dates as well as the season.
In an earlier post I wrote:
*
llewelly wrote in 578:
Agreed. As I pointed out in one post:
As for sea ice, it would appear that the increase in sea ice in Antarctica is occuring largely in one area. Quoting from another recent post of mine:
There I mention that a large part of the reason why we are seeing increased sea ice in the Ross Sea would appear to be due to increased fresh water from the melt taking place along the West Antarctic Peninsula. Ike Solem points out in the very next post that the warm maritime air is gradually moving south along the peninsula. And naturally enough, the melting follows with it. For example, the Larsen B disintegrated in 2002. That was 5°N of the Wilkins Ice Shelf. The ice bridge protecting the Wilkins Ice shelf disintegrated only a week or two ago. And only 5 °S of the Wilkins Ice Shelf the West Antarctic Peninsula ends and the main continent — as well as the West Antarctic Ice Sheet begins.
Oddly enough, nearly the whole of the Southern Ocean would appear to be warming:
Moreover, the increase in sea ice in the past two or three decades is after dropping precipitiously in the earlier part of the Twentieth century. We still aren’t back to where we were during the early 1970s — and the decline prior to the 1970s appears to have been rather dramatic.
Please see:
Sea Ice, North and South, Then and Now
October 8, 2007
http://tamino.wordpress.com/2007/10/08/sea-ice-north-and-south-then-and-now/
A Response to llewelly, Part II of II
Increased fresh water results in the growth of more sea ice in atleast two different ways. First of all, fresh water freezes at a higher temperature than sea water. Secondly, fresh water is less dense than sea water — which leads to a stratification rather than overturning of water layers, insulating the surface from the warmer, saltier water below.
This may prove problematic in terms of deep water formation.
As I stated in an earlier post:
The Arctic Ocean and Southern Ocean are where a great deal of deep water formation takes place. The Arctic Ocean is near Greenland — and may in the long-run be considerably affected by the melting taking place there. Likewise, the Southern Ocean will be strongly affected by the melting taking place in West Antarctica. Rapid climate change — with the shift in deep water formation and ocean currents — is a possibility, although perhaps not a great one in this century. However, since rapid warming is taking place in both hemispheres at once (unlike the Dansgaard-Oescher events), another possibility would seem to present itself: the breakdown of general ocean circulation. In any case, ocean circulation is changing along continental shelves in a way that is consistent with what models at least predict (due to the more rapid warming one continents than in the oceans as the result of oceans having greater thermal inertia) — already leading to giant algae blooms off the Oregon and more recently Washington coasts — and periodic, giant dead zones below due to conditions of anoxia.
Furthermore, at least in the Arctic, if there is a reduction in the circulation of warm ocean water from the depths with colder surface water below, this will tend to reduce the oxygenation of the ocean as a whole. Moreover, at least in the Arctic regions it may put the shallow water methane hydrates which are known to exist (at least along the Siberian continental shelves) at greater risk. And since ocean productivity is largely a function of oxygen and the capacity to carry oxygen increases with colder temperatures, the Southern Ocean naturally enough has supported more life than in other parts of the ocean — and as methane is produced by organic decay, I would expect there to be sizable methane hydrate deposits along the shelves of Antarctica.
*
In any case, your post brings to mind another recent article — one that emphasizes the instability of the West Antarctic Ice Sheet…
According to this article, the West Antarctic Ice Sheet has the ability to raise sea levels by five (rather than six) meters:
According to ice cores, the West Antarctic Ice Sheet is much more unstable than people had thought:
It would appear that conservatively we are looking at a future in which the West Antarctic Ice Sheet is gone:
Conservatively, the rate at which this will take place is on the order of one to three millenia:
However, nature may have some surprises in store for us:
Timothy:
A convenient way of tracking the sea surface temperatures is provided by the U.S. Navy map:
https://www.fnmoc.navy.mil/ncoda_web/dynamic/ncoda_1440x721_global_anom.gif
A particularly “hot” band running between southern tips of Australia, Africa and So. America has persisted for some considerable time, though it might presently be cooling somewhat.
Also No. Atlantic might be cooling a little, at least in my opinion. At times one might suspect a splitting of the Golf Stream, a southern branch pointing towards Britain/France.
These changes are rather slow.
Thank you, Timothy. Some of your earlier comments I had missed and others I had forgotten.
It seems once tipping points are reached ice melt and sea level rise may speed up considerably, not to say catastrophically, according to new research published in Nature. This research suggests about 2-3 meters of sea level rise in 50 years has occurred about 121.00 years ago:
http://climateprogress.org/2009/04/15/nature-sea-level-rise-global-warming-reefs/
How plausible is this, and would this be possible again later this century/the coming centuries?
llewelly wrote in 583:
Honestly, I wasn’t trying to turn my post into “Timmy’s Greatest Hits,” although I believe it may have come across that way. (In my view, that would be a fundamental mistake. I myself lean towards the belief that there is a selflessness to true self-actualization — since it is reality-centered rather than self-centered — as consciousness is primarily about something other than itself.)
However, unlike when I am debating someone, I felt a little more comfortable just linking to some of my earlier posts when engaging in a little discussion, and I like to show how things are interconnected. So I link — and make available other earlier material of mine which I know will also have links.
It is easier to link to my own material since I will better remember the content and even some of the words which I can search for — if I haven’t repeated those words too many times in my more recent posts. But if you have the time to look up posts by others (along the same topic as what you are currently posting on) rather than your own, there are fairly important benefits to doing this — and I sometimes made a point of it at DebunkCreation. And it takes more time — as you will tend to have a better memory of what you wrote as you actually went through the process of writing it. Everything else being equal, writing is a bit more intensive a process than reading — and as a result tends to form better memories. (Additionally, my response was too extemporaneous — and too disorganized.)
*
In any case, I have had a few more thoughts in the interim. First, the biological productivity of the ocean will obviously be more plant than animal — as biomass must necessarily be arranged in ascending order from carnivore to herbivore to plant. (In fact, if I remember correctly, carnivore to herbivore is typically on the order of 1 to 100. Something similar no doubt applies in the ratio of herbivore to plant biomass.)
That being the case, the carbon dioxide suspended by the colder waters will be more important than the oxygen in terms of the generation of biomass and consequent decay into methane and the formation of methane hydrates. Second, one can easily point out to the public that warmer tropical waters are clearly less productive than polar water — because the water is much clearer in the tropics — assuming the topic comes up.
Likewise, one can point out that the oceans will be less biologically productive as the ocean waters warm. However, as the result of the seasonal upwelling of ocean water and nutrients along the coasts due to the more rapid warming of land than water, algae at least will do better for a while. And rather than being carried out to sea, the algae will remain closer to the coasts where we will have the giant algae blooms and consequent seasonal organic decay when the blooms die for the year — which results in dead-zones as oxygen is used up by that decay.
*
Finally, there should be an important feedback due to ocean stratification in the polar regions, at least in the case of West Antarctica. With warmer ocean water below, there should be more melting near the base of the ice — and as such ice will tend to more easily be freed from the surface to which it is attached — at least in the case of ice shelves — and the West Antarctic Ice Sheet when it becomes vulnerable as its base is below sea level. And as more ice is set free, this will lead to more fresh water at the surface, and thus more stratification, further insulating the saltier, warmer ocean water below from the colder polar atmosphere above.
Wilkins ice shelf collapse continued: And an other (small) part of the shelf into fragments. See website ESA, image 20 April, north-east of Latady Island.
PS to 585
To llewelly — in any case, my apologies. My response to you was a little rushed and not as well thought out as it should have been. With the other things going on in my life I am sorry to say that I was a bit distracted.
According to an article in the New Scientist, part of what is driving the warming along the West Antarctic Peninsula and cooling in the Ross Sea is the ozone hole:
However, the ozone hole is beginning to heal, and so presumably the trend in Southern Ocean sea ice growth should reverse itself in about ten years:
Um, problem here is that the photo being used dates to 2006 when the wilkins ice shelf collapsed, and it appears from satellite photos that it collapses regularly every year. So please explain how this years collapse is important.
[Response: Every year it collapses a little more. The most recent change was the collapse of the bridge between Charcot Island and the rest of the shelf. This pretty much completes a process that has taken a couple of years to play out. – gavin]
Somewhere it was mentioned above that this (or another) ice shelf had been in place for 10,000 years. I know from another part of this website of a glacier in the tropical Andes with ice that had been intact for 1000 or 1500 years that is now being disturbed by melting. I vaguely recall reading that Kilimanjaro has had some ice continuously for 10,000 years. I also remember some Arctic ice shelves (not sea ice) that had recently broken up.
Is there a listing of the ages of various bodies of ice that are now or may soon be melting or disintegrating? (PS understanding that going back thousands of years, ice formation in the low latitudes will shift in latitude with the precession cycle).
Patrick 027 wrote in 590:
I don’t have the list you are seeking. However, the Larsen B had existed for 10,000 years.
Please see:
The Wilkins Ice Shelf is old…
In an article at the BBC, it states:
.. but not any where near as old and appears to have been less stable in the past:
What is the current state of the Wilkins platform?
[Response: Here, – gavin]
(And when will “collapse” finally mean “detatch from the continent and melt”, as it is suggested every time these news are around?)
“And when will “collapse” finally mean “detatch from the continent and melt”, as it is suggested every time these news are around?”
When it detatches from the continent.
Which happens to the end of a glacier all the time.
Or do you mean “the entire shelf” well, again, that ice is being replaced, so what was the end that was detatching is now half way down and the end that was the head of the shelf is no longer the same bit.
Mark: #594
http://nsidc.org/data/iceshelves_images/wilkins.html
Choose Wilkins MODIS Images from various times over the past seven years or so. You may have to adjust the zoom level in your browser.
I’m no expert but it doesn’t look to me like the routine calving off the end of a glacier, if only because it’s not a glacier. The whole thing appears to be disintegrating in quite a spectacular fashion.
(My apologies if this is a repeat – software issues.)
I was explaining how “when will “collapse” finally mean “detatch from the continent and melt”, as it is suggested every time these news are around?” was a silly bleegind question to ask, since you have to define what is meant by several of those terms.
And it even depends on what the ASKER means by “detatch from the continent and melt”, since what bit detatching will not constitute what the OP was complaining about having been talked about before.
The incredibly bad wording is partly because we have poor definitions.
Again showing that the OP had a bad request.
Re 591 – Thanks
Spectacular disintegration continues.
Can A boundary layer meteorology expert explain what happens whit to the air (in winter and summer) immediately above
the ice when the it is thinner? Or when there is no ice as with Wilkins case, compared to when there was some very thick ice?
#599- To continue why I ask, I’ve noticed an increase in same date NIR satellite warm ice signatures around Greenland’s glacier walls, from the 80’s when it was sharp white (very cold) to now, much more grayish (warmer)), this may be happen as well around the Wilkin’s Glacier. We all know that Greenland’s glacier’s are calving more and more faster. If there is a model simulation of warmer air profiles, due to thinner or no ice, next to glaciers, it would be interesting to see the difference in profiles, as also a means to explain direct warmer air impact.
Some of My most recent sun disk observations are a bit complicated by the advent of thinner sea ice, which appears to have increased the number of micro-inversion layers near the horizon (Alastair should be interested!), from what I gather, the lower atmosphere radically changes in colder air when there is an extra influx of thermal IR from thinner ice. Looking at model profiles would help understand these changes, the key issue being inversion heights with respect to the astronomical horizon, earlier sunsets seems to indicate that inversion heights are rising (model confirmation???). And the smaller isothermal layers within, infer a complicated interchange of heat. What I am seeing is a cross between summer temperate zone sunsets, and real cold ones, they are so complex as to baffle. There seems to be reason behind this madness.