Antarctic ice shelf collapse possibly triggered by ocean waves, Scripps-led study finds

Feb 11, 2010
A close-up view of Antarctic icebergs as photographed from the Scripps Institution of Oceanography research vessel Roger Revelle. Credit: Jim Swift, Scripps Institution of Oceanography at UC San Diego. Credit: Jim Swift, Scripps Institution of Oceanography at UC San Diego.

Depicting a cause-and-effect scenario that spans thousands of miles, a scientist at Scripps Institution of Oceanography at the University of California - San Diego and his collaborators discovered that ocean waves originating along the Pacific coasts of North and South America impact Antarctic ice shelves and could play a role in their catastrophic collapse.

Peter Bromirski of Scripps Oceanography is the lead scientist in a new study published in the journal that describes how storms over the North Pacific Ocean may be transferring enough wave energy to destabilize ice shelves. The California Department of Boating and Waterways and the National Science Foundation supported the study.

According to Bromirski, storm-driven ocean swells travel across the Pacific Ocean and break along the coastlines of North and South America, where they are transformed into very long-period waves called "infragravity waves" that travel vast distances to Antarctica.

Bromirski, along with coauthors Olga Sergienko of Princeton University and Douglas MacAyeal of the University of Chicago, propose that the southbound travelling infragravity waves "may be a key mechanical agent that contributes to the production and/or expansion of the pre-existing crevasse fields on ice shelves," and that the infragravity waves also may provide the trigger necessary to initiate the collapse process.

A view of Antarctica's Ross Ice Shelf and the deployment location of a seismometer. Credit: Joe Harrigan

The researchers used seismic data collected on the Ross Ice Shelf to identify signals generated by infragravity waves that originated along the Northern California and British Columbia coasts, and modeled how much stress an ice shelf suffers in response to infragravity wave impacts. Bromirski said only recently has technology advanced to allow scientists to deploy seismometers for the extended periods on the ice shelf needed to capture such signals.

The study found that each of the breakup events in 2008 coincided with the estimated arrival of infragravity waves. The authors note that such waves could affect ice shelf stability by opening crevasses, reducing ice integrity through fracturing and initiating a collapse. "[Infragravity waves] may produce ice-shelf fractures that enable abrupt disintegration of ice shelves that are also affected by strong surface melting," the authors note in the paper.

Whether increased infragravity wave frequency and energy induced by heightened storm intensity associated with climate change ultimately contribute to or trigger collapse is an open question at this point, said Bromirski. More data from Antarctica are needed to make such a connection, he said.

In separate research published last year, Bromirski and Peter Gerstoft of Scripps Oceanography showed that infragravity waves along the West Coast also generate a curious "hum" -- subsonic noise too low for humans to hear.

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User comments : 45

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freethinking
2.2 / 5 (13) Feb 11, 2010
Finally science. Not one mention of AGW as the cause.
bbd
4.1 / 5 (9) Feb 11, 2010
Finally science. Not one mention of AGW as the cause.

Oh, forgot to mention ... the waves are caused by global warming.
freethinking
Feb 11, 2010
This comment has been removed by a moderator.
Ronan
3.4 / 5 (5) Feb 11, 2010
Bear in mind, Freethinking, that if you cut global warming out of the picture you still have to explain why these ice sheets are going kerblooey now (and staying gone), and don't seem to have done that in the past. SOMETHING'S changing.

...That aside, though, amazing how long-distance this is! Pretty impressive, something a third of a planet's-width away triggering a collapse of an ice sheet. East Antarctic ice sheets are holding up magnificently now, but I wonder if, in the future, this sort of triggering could also apply there, or whether it's only possible with the geometry of the North and South American coastline?
TegiriNenashi
3 / 5 (6) Feb 12, 2010
Don't panic! Don't panic! According to wikipedia Ross Ice Shelf expands with the speeed 1.5 meters .............. a day! That makes 0.5 kilometer a year. Give it some time (10-50 years) to grow and, sure enough, once in a while somewhere on a vast antarctic coastline a large iceberg breaks out.
CyberRat
2.5 / 5 (4) Feb 12, 2010
If the climategate facts are true, means the poles warm up, means less temperature difference between the pools and equator, means less storms/wind, means less waves.
mikiwud
2.2 / 5 (13) Feb 12, 2010
Bear in mind, Freethinking, that if you cut global warming out of the picture you still have to explain why these ice sheets are going kerblooey now (and staying gone), and don't seem to have done that in the past. SOMETHING'S changing.

Is it?
Anthony Watts showed photos from archives of the ice shelves breaking up for the first time (headlines) in 2009, 2008, 2007.... and they were the same basic photos, just different sizes and slightly different angles.
Ice shelves float, so are acted on by waves and tides. The stress on them must increase as the get further from land.
JayK
Feb 12, 2010
This comment has been removed by a moderator.
mary_hinge
3.3 / 5 (7) Feb 12, 2010
The greatest scientist of our day, Anthony Watts?

I think that should read "the greatest ANTI-scientist f our day, Anthony Watts?" A more accurate description of our ex-'fair and balanced' weatherman!
JayK
3.3 / 5 (7) Feb 12, 2010
b-b-b-b-bBut he found all that UHI in the system and the numbers are off. Haven't you read all of his peer-reviewed journal publications, mary_hinge?

Just remember, ice coverage is the same as ice mass to a professional like Anthony Watts.
TegiriNenashi
2.3 / 5 (9) Feb 12, 2010
Perhaps subtle sarcasm of calling Anthony Watts "the greatest scientist" escapes me. He speaks to a wide audience, so many science popularizes do. Call Martin Gardener "the greatest scientist" and you'll get blank stare. Is it the damage that he inflicted on the Church Of Global Warming that bothers you?
JayK
3.2 / 5 (9) Feb 12, 2010
No, it is damage to the ideas of science by attempting to appeal to the lowest common denominator with pseudoscience and emotional pleading.

Anthony Watts is as much a scientist as Joe the Plumber or Sarah Palin. They all have a lot in common, but science really isn't one of those things.
Skeptic_Heretic
2.3 / 5 (9) Feb 12, 2010
Is it the damage that he inflicted on the Church Of Global Warming that bothers you?
In the same vein as your statement, there are still a great many astronomers and cosmologists who bear a grudge against Carl Sagan.

No, it is damage to the ideas of science by attempting to appeal to the lowest common denominator with pseudoscience and emotional pleading.

I'm sorry but you need to take a step back and rethink this comment. Watts makes all of his evidence available in each article. I do not see a similar conversation occuring on realclimate.org.

FYI: the polar bear argument, doesn't get much more emotional sans substance than that.
JayK
3.5 / 5 (8) Feb 12, 2010
I do not see a similar conversation occuring on realclimate.org.


Yeah, you don't read realclimate much, do you? Watts' evidence is usually equivalent to how cold/hot it is in his backyard. Right now he's talking about how bad snowmogedon is for global warming. Thats some top notch science there.
Skeptic_Heretic
2.8 / 5 (9) Feb 12, 2010

Right now he's talking about how bad snowmogedon is for global warming. Thats some top notch science there.

On the contrary I've read it many a time. I like to read all of the information available, not just one side, otherwise how could I create an opinion of any type about the discussion?

Watts stated there were problems with monitoring stations. He then followed that up by pulling the regulatory documents for monitoring stations and went out taking photographs of the existing stations. That was verifiable evidence for his hypothesis. When a station was moved or repaired he stated they had been moved or repaired since his photograph. No duplicity there.

When he runs a statistical reconstruction he provides full source code, very few, if any, of the more alarmist AGW proponents have released their models without the interference of legal authority. I must say, I wholeheartedly disagree with your conclusions and I think you're not being as open minded as you should.
JayK
3.3 / 5 (7) Feb 12, 2010
Are you done editing your post yet?

http://icb.oxford.../163?eaf

Wow, there's some emotional stuff there, a peer-reviewed journal entry. Hard to read without the tears just streaming.

Maybe this line is the one that really grabbed my heart strings:

In the short term, climatic warming may improve bear and seal habitats in higher latitudes over continental shelves if currently thick multiyear ice is replaced by annual ice with more leads, making it more suitable for seals.


Wow, I'm emotionally vercklempt now.
JayK
3.3 / 5 (7) Feb 12, 2010
What happens when you remove all of the questionable temp monitoring stations, Skeptic? Come on, you should know the answer, right? You know what happens to the graphs, right? You know how the big massive delta appears, like magic? Or maybe it doesn't, or maybe you're just not aware. Realclimate posted everything about this topic about a year ago, you read that, right? And you grabbed all of their data, because it was all right there, right?

I have no open mind when it comes to hucksters like Watts.
Skeptic_Heretic
3 / 5 (6) Feb 12, 2010
Well I must say, this statement from Realclimate really makes me see them as an unbiased source of scientific insight.

How to be a real Sceptic- http://www.realcl...sceptic/

Another great informative article:
http://scienceblo...ptic.php

JayK
3 / 5 (6) Feb 12, 2010
If you think Watts' UHI obsession somehow has some veracity?

http://www.realcl...-island/
Skeptic_Heretic
2.7 / 5 (7) Feb 12, 2010
JayK,

When you remove the huge amount of questionable stations you no longer have enough data to come to a conclusion in either direction.

As I've said from start to finish, I'm unsure as to what's happening. Until there's enough data for me to formulate an opinion I'll continue to read and debate hypotheses based upon the facts of the matter, not the name calling or assertions of media-washed individuals.
Skeptic_Heretic
2.7 / 5 (7) Feb 12, 2010
And the UHI is a proven phenomina, the question is how was it accounted for within the monitoring network.

Problem is no one will answer that question clearly.
JayK
3.3 / 5 (7) Feb 12, 2010
When you remove the huge amount of questionable stations you no longer have enough data to come to a conclusion in either direction


Who says? And when the new data coincides with ongoing satellite data?

All denialists continue to do is nitpick without addressing the big picture. If you're truly a skeptic of both sides, then Watts probably isn't a source that you even want to use. Just take his focus on local weather to make the case for his own denialism. That right there makes him nothing more than an emotional blogger with a large audience of like minded individuals uninterested in the actual science.
Skeptic_Heretic
3 / 5 (8) Feb 12, 2010
I don't use watts as a reference. I do read his site, just as I read realclimate and the enquirer.

And a great many people say our current monitoring network is insufficient. The monitoring network is what the satellite is normalized against.

If the foundation of your house isn't certain, you can't assume the second floor is level. Be open minded, read everything you can, and formulate your own opinion, don't repeat Anthony Watt's opinion, Michael Mann's opinion, McKitrick or McIntyre's opinion, repeat JayK's opinion (I don't know you're real name), and make sure you revise that as you learn more.
Skeptic_Heretic
3.2 / 5 (9) Feb 12, 2010
And whatever you do, certainly don't repeat anything Gore says.

If he wasn't so ridiculous the majority of this entire discussion would probably have already been quietly discussed and settled.
JayK
3.2 / 5 (9) Feb 12, 2010
I never said that UHI wasn't real, neither have the climate scientists. Right there is an example of the tactics that denialists use, trying to imply that climatologists aren't taking everything into account or that they ignore certain things that the denialists are absolutely sure about.

http://www.realcl...-island/

http://www.realcl...-island/

http://www.skepti...fect.htm

http://www.spring...8b6knbf/
JayK
3.2 / 5 (9) Feb 12, 2010
As you've no doubt seen before, I decry the overall anti-intellectualism that is at the heart of the denialism claims. For those that have never been through the peer-review process, for those that wouldn't even recognize the difference between Watts' blog and a peer-reviewed journal entry, I just don't have the time.

Gore offered his opinion. Some of them were incorrect, some of them were right on, and some of them were exaggerated. We're past Gore at this point, he is no longer anything other than a focus for denialists' slander and scolding.

But when you just take the time to narrow down the noise on climate change down to those who know something about the paleontology, geographical data, climactic processes and the general physics of the various topic, then you find out that everyone else is parroting the same denialist BS.

That cuts down on how much I read, dramatically.
Skeptic_Heretic
2.6 / 5 (8) Feb 12, 2010
As I said above, "The question is how was it [the UHI] accounted for in the monitoring network. I never made a statement as to your beliefs on the subject. You very easily apply the term for holocaust deniers to those who are sceptical of AGW. That is a flaw in your reasoning.

I decry the overall anti-intellectualism that is at the heart of the denialism claims.

I also disagree with "denialist" claims, the difference is you seem to reinforce unfounded alarmist cries rather often.

Limiting what you read removes the ability to make the discerning process valid. Above you quote a polar bear paper, but I'm fairly sure you wouldn't have even thought of it unless the issue was brought to light by Mr. Gore, father of the multimillion degree sub terranean power plant and creator of the internet.

There's a lot of noise on climate change, we both agree, however you seem to only be concerned with the noise on one side of the issue. Both sides are equally culpable of fraud.
Skeptic_Heretic
1.9 / 5 (7) Feb 12, 2010
Freethinking,

Although I appreciate the support, abusing the ranking system is only serving to prevent conversation between myself and JayK, please refrain.
JayK
3 / 5 (8) Feb 12, 2010
And how is the polar bear issue wrong, Skeptic? While the current numbers of bears might be increasing, the threat they face from massive environmental shutdown is pretty clear. If Arctic ice thaw continues along the path that it has been for the last couple decades, there will be periods where the bears will be unable to cope and massive die offs will happen. Thats what that paper was about.

I limit what I read to those that can actually earn respect. Watts and his lackeys don't deserve the respect or the time. They may ask the questions, but they never listen to the actual answers. Who has time for that kind of tripe?
Skeptic_Heretic
2.7 / 5 (7) Feb 12, 2010
there will be periods where the bears will be unable to cope and massive die offs will happen.
I'd like to know what the justification for that is. Polar bears live off the land for the majority of the year, not off of sea ice. Polar Bears have further adapted to take advantage of the changes in the environment brought on by humans. They've also been seen rather far south and in some instances have mated with other species of bear and survived within non-native environments. Polar bears don't live on the poles because they want to or because they can't live else where. This is why the statements are incorrect. In Canada we saw them as a menace most times. Their population booms would result in more and more invasions into human territory.

As for Watts and "his ilk" who exactly does that refer to? (Just the big names, who cares about bloggers)
freethinking
2.3 / 5 (9) Feb 12, 2010
Sorry Skeptic, Will do.

I think your comments make the most sense (though I hate to say it)
JayK
3.3 / 5 (7) Feb 12, 2010
I handed you the paper from the experts on polar bears and you didn't read it?

A cascade of impacts beginning with reduced sea ice will be manifested in reduced adipose stores leading to lowered reproductive rates because females will have less fat to invest in cubs during the winter fast.


Give me some kind of indication that your qualifications for polar bears is somehow greater or equal to the authors of that journal article or you're just being skeptical with no basis and you're wasting my time.
TegiriNenashi
2.1 / 5 (7) Feb 12, 2010
Anthony Watts is as much a scientist as Joe the Plumber or Sarah Palin. They all have a lot in common, but science really isn't one of those things.


Perhaps your definition of "science" is different than mine? Do you realize that the people you seem to admire (Mann, Hansenn, Schmidt to name a few) are mediocre scientists, at best? They don't really have any inspirational ideas to offer other than shamelessly exploiting the AGW ride. By "inspirational" I mean those that rarely get much press, but are capable redefining the world as we know it.

TegiriNenashi
2.1 / 5 (7) Feb 12, 2010
I believe the polar beer issue is not scientific, hence Richard Feynman quote:

"I believe that a scientist looking at nonscientific problems is just as dumb as the next guy."

MikeyK
3 / 5 (4) Feb 12, 2010

Perhaps your definition of "science" is different than mine? Do you realize that the people you seem to admire (Mann, Hansenn, Schmidt to name a few) are mediocre scientists, at best? They don't really have any inspirational ideas to offer other than shamelessly exploiting the AGW ride. By "inspirational" I mean those that rarely get much press, but are capable redefining the world as we know it.

Do you mean like Flash Gordon, Captain Kirk etc. Have you thought about why they don't get much press, basically they talk bollocks and on't go through the normal peer-review. How can you take them seriously if they publish through 'Good Ol' Boy' nutmags?
Hey, as Sarah Palin would say ".....damn, ...I had it written down here somewhere.....oh yeah, you've got to HAND it to Watts, he never tried to PALM this off on anyone. " Haven't laughed so much as when Lord Monckton had his Hitler Youth moment. Bye the way I'd love a bottle of this Polar Beer if there's any goin'
Skeptic_Heretic
3.8 / 5 (4) Feb 13, 2010
Give me some kind of indication that your qualifications for polar bears is somehow greater or equal to the authors of that journal article or you're just being skeptical with no basis and you're wasting my time.

I'm a former memeber of PBI and was engaged as a scout for the research team that wrote the Davis Straight research papers in addition to working as a junior researcher on the Nunavut expedition in 2004-2007.

Polar bears to not require seals and high fat content diets to raise their young. The most dangerous thing in the world to a polar bear, aside from Sarah Palin, is another older, larger polar bear. Polar bears are highly cannablistic and will eat their own young without much thought once they pass their first year. The most damaging thing to polar bears is urbanization and human boundary establishment. The good news is that for the most part this is not a threatening issue, but if oil development continues the urbanization it brings with it creates conflict.
dachpyarvile
2.1 / 5 (7) Feb 13, 2010
Given the fact that polar bear populations are increasing rather than decreasing overall, I'd say that they are not in trouble anytime soon. You do not have population booms in times of food scarcity and do not have increases in the population of the young in times of famine or poor nutrition.

Aside from this, I am glad that the above article was written and that the fact of 'seismic' action on the shelves by the waters is mentioned. CO2 and so-called AGW got the blame and now another mechanism is known that plausibly explains the collapse. For this reason I highly doubt that the EAIS will be affected the same way as the WAIS. I hope to see more studies like this and the data that they will reveal.
JayK
3.8 / 5 (4) Feb 13, 2010
Sorry, Skeptic, but that sounds like you cut and pasted it out of an 8th grade animal sciences book, not as if you were actually a researcher of any kind. And now that dacharpy is here, this thread is useless.
dachpyarvile
1.5 / 5 (8) Feb 13, 2010
Doesn't matter, JayK et al. This article does not discuss polar bears so your bringing them up, technically speaking, is off-topic.

Now, how do you feel about this above latest study. Please do not hide your true feelings. The evidence is there potentially supporting the study. Please show why the data is invalid, falsify the study and offer something more valid than mere pedantry, insults and sockpuppetry.
VeIanarris
3 / 5 (2) Feb 13, 2010
Well spoken JKay, as soon as the moron gets on and spouts on about sockpuppets then its best not to waste your time with thge troll from the abyss.
Incidentally dachypy does realise that every user here is in effect a 'sockpuppet (what a ridiculous word.) Being anonymous you can be whoever you want to be, so how come dachpy wants to portray himself as a total twat?
JayK
1 / 5 (2) Feb 13, 2010
If dachy had taken just a few moments to read the comment thread, rather than spouting off an attack against me, he might have noticed he made an assumption that made him look like a fool. Of course, that kind of reading is beyond him, much like it appears to beyond most denialists when I comes to reading the reports the journal articles or anything else that has more than 3 sentences.

Skeptic_Heritic writes well, articulates his points well (usually) and has actually encouraged me to do further research on a few things. Dachy/freethinking/marjon and the rest of them do nothing but parrot the latest Watts creed and pretend that they actually understand.
dachpyarvile
1 / 5 (6) Feb 13, 2010
Interesting--considering I have never brought up anything relating to Watt. I have never cited anything from him, so far as I can recollect. It is funny, though, that as soon as sockpuppets are mentioned they start coming out of the woodwork again.

Additionally, see the definition of sockpuppet here:

http://en.wikiped...nternet)

Fits Jay/MikeyK/Veianarris et al., like a glove.

Now, how about that eloquent falsification of the data in the study mentioned in the above article...
Skeptic_Heretic
3.7 / 5 (3) Feb 14, 2010
Sorry, Skeptic, but that sounds like you cut and pasted it out of an 8th grade animal sciences book, not as if you were actually a researcher of any kind.

Sorry you feel that way. Your response still does not provide substance to your viewpoint.
VeIanarris
1.7 / 5 (3) Feb 14, 2010
Sorry you feel that way. Your response still does not provide substance to your viewpoint.

He is probably alluding to your poor terminology, spelling and syntax which would not be the habits of someone with the experience you say you have. Like your identical twin Dachpy Quack you seem to inhabit a strange fantasy world where you are a researcher, a public speaker, face death threats and are Canadian (prsumably French Canadian as English is not your first language. I suppose this week you are mostly a Quebec spy dodging the bullets from the evil Trotskyists...but at leats you will have time to write that bestseller novel and maybe hit the winning run..... Heck, I suppose its more fun than reality for you..
Skeptic_Heretic
not rated yet Feb 14, 2010
Interesting, but inaccurate.

I'm German born, moved to Canada in my teens, studied electrical engineering at the SAIT, completed a masters in the field at Northeastern University and was recruited by multiple organizations throughout my career for my prowess at developing weather resistant monitoring devices primarily for soil enrichment projects.

My apologies if you don't seem to understand that real people with real backgrounds exist in a personable and interactive way. Then again I am talking to a forum ID that appears to have been "copied" from another, now silent, physorg poster who could tell the difference between an I and a L.

I can also see you're well informed in the practice of research seeing as you doubt active researchers do any public speaking on the topics of their research.

My apologies to the rest of the community for this post. I typically do not engage in feeding the trolls.
Skeptic_Heretic
not rated yet Feb 14, 2010
Also, Veianarris, why are you so quick to speak for him on the matter? JayK is a big boy, I'm sure he can convey his apprehension without your assistance.
croghan27
not rated yet Feb 14, 2010
Sorry, Skeptic, but that sounds like you cut and pasted it out of an 8th grade animal sciences book, not as if you were actually a researcher of any kind. And now that dacharpy is here, this thread is useless.


I have to side with Skeptic H on this one .... the problem is less polar bears encroaching on human territory than it is human moving into what is usually their's.

There were very few reports of human/polar bear interactions until INCO - the Inuit had learned to live with them centuries ago, moved into Thompson - then they became an urban problem.