Disappearing snow increases risk of collapsing ice shelves in Antarctica

Jan 29, 2014
Credit: Newcastle University

A number of floating ice shelves in Antarctica are at risk of disappearing entirely in the next 200 years, as global warming reduces their snow cover. Their collapse would enhance the discharge of ice into the oceans and increase the rate at which sea-level rises. A rapid reduction of greenhouse gas emissions could save a number of these ice shelves, researchers at Utrecht University and the British Antarctic Survey say in a new paper published today in the Journal of Glaciology.

Back in 1995 and 2002, two floating ice shelves in the north of the Antarctic Peninsula (Larsen A and B) suddenly collapsed – each event occurred in a matter of weeks.

Dr Peter Kuipers Munneke, the paper's lead author, said:

"This was a spectacular event, especially when you imagine the size of these ice shelves, which are several hundreds of metres thick, and have been in place for over 10,000 years."

The team of researchers suspected that the disappearance of the snow layer on top of the ice shelves could be an important precursor for shelf collapse. Their calculations confirm this hypothesis, and show that many more ice shelves could disappear in the next 200 years.

The scientists believed the snow layer plays an important role in regulating the effect of meltwater lakes on the ice shelves.

As long as the snow layer is sufficiently thick and cold, all meltwater can sink into the snow and refreeze. But in a warmer climate, the amount of meltwater increases, and the snow layers become thinner.

As a result, meltwater can no longer refreeze and forms large lakes on the surface of the ice shelves. The water drains through cracks and faults, causing them to widen until they become so wide and deep that the entire ice shelf disintegrates.

After their collapse, ice shelves can no longer provide resistance to the flow of the glaciers previously feeding them. As a result, the glacier flow accelerates significantly, contributing to an increase in sea-level rise.

The researchers performed calculations that show how this process may evolve over the next 200 years, using two different climate scenarios.

Dr Kuipers Munnekke said: "If we continue to burn fossil fuels at the current rate, almost all ice shelves in the Antarctic Peninsula will be under threat of collapse in the next 200 years. Only the two largest ones seem to be safe. Even in the much colder eastern part of Antarctica, some ice shelves could disintegrate. If we manage to keep below the European Union target of 2oC, more than half of the could be saved, compared to no action taken on emissions reductions."

The study received financial support from the European Union's four-year ice2sea project. Prof. David Vaughan said "We've been observing ice-shelf retreat around the Antarctic Peninsula since the early 1990s, but for the first time this model provides a strong basis for the prediction of future changes, which is a major step forward in understanding future sea-level changes."

Explore further: Warm ocean drives most Antarctic ice shelf loss, research shows

More information: "Firn air depletion as a precursor of Antarctic ice-shelf Collapse" Peter Kuipers Munneke, Stefan R.M. Ligtenberg, Michiel van den Broeke, David G. Vaughan, Journal of Glaciology, 60 (220), (2014), 10.3189/2014JoG13J183

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MR166
1.7 / 5 (17) Jan 29, 2014
This is a very bad finding. As the sky falls the atmosphere will heat up due to compression further melting the ice around the world. Between the rising seas and falling sky there will be room left to live.
PhotonX
3.8 / 5 (10) Jan 30, 2014
This is a very bad finding. As the sky falls the atmosphere will heat up due to compression further melting the ice around the world. Between the rising seas and falling sky there will be room left to live.
Falling sky? Atmospheric compression? I'm certainly no expert in Earth Sciences, never mind climatology or meteorology, but I feel compelled to ask: What in the world are you talking about?
runrig
3.2 / 5 (11) Jan 30, 2014
This is a very bad finding. As the sky falls the atmosphere will heat up due to compression further melting the ice around the world. Between the rising seas and falling sky there will be room left to live.


Also, those whose illogical, ideological idiocy make them blind to the sky falling, will go on thinking invisible turtles are holding up the Earth and continue sticking their heads in the sand whilst repeatedly popping their heads up, sticking their fingers in their ears and shouting "bblaarrr bbbllllaaarrr" loudly to cover up any possible evidence that may leak through into their tiny minds, as common sense dictates to the rest of us. And in so doing ably demonstrate to an astounded world that they're - well, you know. Stupid.
(sarcasm)
Sinister1812
3.7 / 5 (6) Jan 30, 2014
This is a very bad finding. As the sky falls the atmosphere will heat up due to compression further melting the ice around the world. Between the rising seas and falling sky there will be room left to live.


So you think these are doomsday predictions, do you? Whatever.
runrig
3 / 5 (8) Jan 30, 2014
This is a very bad finding. As the sky falls the atmosphere will heat up due to compression further melting the ice around the world. Between the rising seas and falling sky there will be room left to live.
Falling sky? Atmospheric compression? I'm certainly no expert in Earth Sciences, never mind climatology or meteorology, but I feel compelled to ask: What in the world are you talking about?


Precisely.
MR166
2.3 / 5 (16) Jan 30, 2014
"So you think these are doomsday predictions, do you? Whatever."

These articles are closer to propaganda from the Ministry of Truth than bonafide predictions.
Maggnus
3.7 / 5 (12) Jan 30, 2014
"So you think these are doomsday predictions, do you? Whatever."

These articles are closer to propaganda from the Ministry of Truth than bonafide predictions.

Cause dem SCIENTISTS dey all be CONSPIRATORING to make dat SKY falling an stuff! All CONSPIRATORING togeather and like dat!

MR166
2.1 / 5 (15) Jan 30, 2014
Maggnus no conspiracy is needed since they are all smart enough to know where their bread is buttered. If you want to get your next grant you had better "Prove" something that meets your government's political requirements.
Maggnus
3.9 / 5 (11) Jan 30, 2014
You see MR166, that is a conspiracy you're describing. So apparently in your small little world, there is need for a conspiracy.

Its really too bad you are so caught up in your stupid conspiracy crap that you can't actually learn something from the science. You have nothing to say, so you prove that by saying nothing.

Why don't you go haunt some climate denier boards somewhere? There you'll find a lot of conspiracists, denialists and conspiracist denialists to share your empty political philosophe with.
MR166
2.3 / 5 (12) Jan 30, 2014
If by conspiracy you mean, are the UN and the Progressives using the AGW hoax as a tool to separate the individual from his freedoms and his wealth, then I have to agree there is a conspiracy.
TegiriNenashi
2.5 / 5 (11) Jan 30, 2014
Indeed, the collapse of west antarctic ice sheet has been predicted by Mercer in 1978
http://www.nature...1a0.html
He was talking about polar amplification of 5-10K degrees during next 50 years. It is instructive to compare it with actual observation record
http://www.nerc-b...rend.pdf
http://www.nerc-b...rend.pdf
If those graphs are not convincing, check up the antarctic sea ice coverage (as temperature proxy).
Therefore, yes, there is a conspiracy of not very bright scientists gathering in a certain field and desperately trying to force a flawed hypothesis against public throat.

Maggnus
3.9 / 5 (11) Jan 30, 2014
Indeed, the collapse of west antarctic ice sheet has been predicted by Mercer in 1978
Yes, he predicted that that the WA sheet could be destabilized. So where are we now? http://www.grida....559.aspx
http://www.prince...y-04.pdf
http://www.nasa.g...613.html
So not only was he right, the sheet not just destabilizing, it is destabilizing at a faster rate then he predicted 35 years ago.
Antarctic sea ice coverage (extent) has been growing due to a number of factors, including accelerated WA sheet melt increasing the amount of freshwater at the ocean surface.
So it appears that what we actually have is a bunch of not very bright denialists claiming a conspiracy that doesn`t exist, and desperately trying to use cherry-picked data to prove something that is not true.
Way to go Tegiri, you`ve proven the point.
Maggnus
3.2 / 5 (9) Jan 30, 2014
If by conspiracy you mean, are the UN and the Progressives using the AGW hoax as a tool to separate the individual from his freedoms and his wealth, then I have to agree there is a conspiracy.
Well yea, that`s your view of it. Personally I think it's funny that vested interests that have no scientific backing but make constant cries of political agendas can get gullible and/or not very bright people to think there is a conspiracy to begin with.
TegiriNenashi
2.3 / 5 (13) Jan 30, 2014
The issue reduces to what data do you trust the most. (In case if the irony has been lost on the other readers, note that the two temperature graphs are from the same British Antarctic Survey that coauthored the paper.) So, we have dozens of stations which indicate no warming, while the Bird insists there is? Perhaps, there is a glitch there? Let me emphasize the trivial idea that warming confined to Antarctic Peninsula is by definition not global, and, therefore has to be explained by other means. Finally, I find your explanation of the expanding sea ice cover in the warming world not entirely convincing. I mean, the sea ice melts in summer, and grows in winter because some factor other than temperature? Are you seriously thinking your listeners that dumb?
Maggnus
3.7 / 5 (9) Jan 31, 2014
The issue reduces to what data do you trust the most.
No, the issue is who has the most data. Trust is not a requisite of anything, what is a requisite is what is factual and can be supported by data.
trivial idea that warming confined to Antarctic Peninsula is by definition not global
Well no kidding! The same as cooling in some parts of East Antarctica is not proof that global warming is not occurring. It comes back to data that covers the globe, and the amount of data presented across a wide range of disciplines.
I mean, the sea ice melts in summer, and grows in winter because some factor other than temperature?
Apparently you are having trouble with comprehension, and it appears to be wilful.
Are you seriously thinking your listeners that dumb?
No, but I am starting to think at least one of them is.
MR166
1.9 / 5 (9) Jan 31, 2014
Besides being used as a tool by the few to usurp the rights of the many, the AGW scam is costing hundreds of billions of dollars that we just don't have. These, like many other useless government programs and regulations make day to day life unaffordable for the average family. Yes they might create a few jobs but not all jobs create a net benefit to the public. Many enforce regulations that make the cost of goods and services higher and everyone poorer.
Maggnus
3.7 / 5 (9) Jan 31, 2014
Besides being used as a tool by the few to usurp the rights of the many, the AGW scam is costing hundreds of billions of dollars that we just don't have.
No, it's working to save us hundreds of billions of dollars in damages and the incalculable costs of lost lives resulting from ever more severe and unpredictable changes in weather.
These, like many other useless government programs and regulations make day to day life unaffordable for the average.
What does politics have to do with the science? The science says global warming is happening and you argue it's not happening because you disagree with the costs of government programs. That's not very bright!
TegiriNenashi
2.2 / 5 (10) Jan 31, 2014
The same as cooling in some parts of East Antarctica is not proof that global warming is not occurring. It comes back to data that covers the globe, and the amount of data presented across a wide range of disciplines.


"Some parts of East Antarctica"? That is a serious twist of the data. Once again, the increased ice cover hints that pretty much the whole Antarctic continent temperature hasn't been changed, or might have even cooled. One more time, the polar amplification effect is nothing to sneeze on: if temperature change manifested itself anywhere in the globe, it must be the polar regions.

Where we see exactly nothing. In the absence of firm [err robust] data, your camp has to invoke fairy tales like heat hiding in deep oceans, or melt water affecting sea ice cover. And you wonder why climate science is laughingstock.
Maggnus
3.7 / 5 (9) Jan 31, 2014
"Some parts of East Antarctica"? That is a serious twist of the data.
Really. http://www.news.c...00043191
http://www.thegua...tarctica
http://www.realcl...or-blue/
Once again, the increased ice cover hints that pretty much the whole Antarctic continent temperature hasn't been changed, or might have even cooled.
Really. http://www.newsci...ing.html
http://www.cnn.co...nSTCText
http://www.nature...671.html
That comprehension thing really has you at a loss, doesn't it? You should try spending more time looking at research instead of reading denialist blogs.
Maggnus
3.7 / 5 (9) Jan 31, 2014

Where we see exactly nothing. In the absence of firm [err robust] data, your camp has to invoke fairy tales like heat hiding in deep oceans, or melt water affecting sea ice cover. And you wonder why climate science is laughingstock.


My camp?

No I wonder how laughing stock denialists can ignore so much data in their efforts to promote their versions of the conspiracy they see all around them. You're just another in a long line of those same denialists promoting zombie arguments and playing whack-a-mole with the facts.
TegiriNenashi
2.2 / 5 (10) Jan 31, 2014
Once again, you should develop some critical thinking skills [beyond just pointing to press releases]. One of your sources says:
"Regional cooling does not disprove global warming."
This is nonsence. Once again, google "polar amplification". If global warming signal were noticeable anywhere, then it must be more obvious at the poles. Therefore, the absence of warming in the antarctic disproves AGW. Don't forget the ridiculous numbers - 5-10K/50 years - manufactured by Mercer in his infamous opus.
"In any case, Antarctica has warmed overall over the past 50 years"
Certainly, absence of warming in the Antarctica has bothered many, prompting Steig paper in Nature magazine, where by "clever" adjustments and inventing the data where there was none he "demonstrated" east Antarctica warming. I repeat one more time: the sea ice cover is a very reliable temperature proxy. If ice cover didn't shrink, there is no warming.
Captain Stumpy
3.7 / 5 (9) Jan 31, 2014
@Maggnus
check out this article link below the quote
The third level of discrimination is where most of the action between science and pseudoscience actually takes place, over what I earlier called the operational details of science. Getting these details right helps deliver useful causal explanations.
This is where battles are fought over what constitutes evidence, how to properly use statistics, instances of cognitive biases, the use of proper methodologies and so on.
It is where homeopathy relies on confirmation bias, where the anti-vaccine lobby is energised by anecdotes, and where deniers of climate science selectively highlight agreeable data.


http://phys.org/n...firstCmt

... sound familiar Mag? Especially that last sentence!

the deniers repeatedly cherry pick data to support their own conclusions...
but the deniers dont really understand the data

fits the data in most all climate denier posts
runrig
3.7 / 5 (9) Feb 01, 2014
This is nonsence. Once again, google "polar amplification". If global warming signal were noticeable anywhere, then it must be more obvious at the poles. Therefore, the absence of warming in the antarctic disproves AGW …………..
I repeat one more time: the sea ice cover is a very reliable temperature proxy. If ice cover didn't shrink, there is no warming


Right I'll come in here to whack this particular mole for the nth time.
No it's you who spout nonsense

Correct: "polar amplification" is a particular signal of AGW theory. But you really must examine just how extraordinary is the Antarctic environment – now I have done this several times to bone-headed denialists on here who expect the Antarctic to behave as does the Arctic "because it's a Pole".
But:
It is a massive continent isolated from land mass and has vast ocean surrounding, itself cut-off from the exterior ocean warmth via the ACC (circumpolar current).

Cont
runrig
3.7 / 5 (9) Feb 01, 2014
Cont

The average height of the continent is 12000ft.
It has an enormously intense vortex (trop and Strat) – which WILL not be shifted – and made colder by CFC destruction of O3.

These major differences make it totally incomparable with the Arctic.

Sea ice is NO WAY a good temperature proxy – Why? Because of salinity and wind flow in a region where ice is free to be blown further away from the coasts (the Arctic is effectively a contained environment).
Sea-ice can be formed anywhere from a temp of 0C to –2C. OK. Please let that sink in. Sea-ice free to move on an ocean where salinity can be significantly reduced via summer melt water from coastal ice and blown via continental divergent winds IS NOT A GOOD PROXY for temps – in fact it's a very bad one. But of course people like you will twist the science and proclaim that the world's experts are mere infants at your magnificent feet.
MR166
1.8 / 5 (10) Feb 01, 2014
So let me get this straight.
Antarctic sea ice is only a reliable temperature proxy when it is melting. If it is increasing it is meaningless. Also, all of those computer simulations predicting the melting of Antarctica are wrong because of CFCs .

Lastly, today's Arctic melting is unprecedented and 200 years news reports of substantial changes in Arctic ice coverage need not be acknowledged.
Maggnus
3.7 / 5 (9) Feb 01, 2014
So let me get this straight.
Really wish you would! No it is not meaningless, there are causes. The causes are being investigated. The investigation is revealing that the dynamics of a warming world are changing the planet, including Antarctica. The changes that are affecting Antarctica include giga-tonnes of melting from it's continental ice sheets. The increased melting from the ice sheets is affecting the layering of the ocean. The layering of the ocean is resulting in the production of sea ice. The production of sea ice is causing the extent of sea ice to grow. The amount of sea ice being produced is not as much as the amount of melting coming from the ice sheets. Ergo, the higher extent of sea ice cover IS meaningful.

Lastly, today's Arctic melting is unprecedented and 200 years news reports of substantial changes in Arctic ice coverage need not be acknowledged.
How many times must you be told that the Arctic and the Antarctic are different? Can you imagine why?
VINDOC
2.5 / 5 (11) Feb 01, 2014
Climatology is garbage science. All past data has been altered. If you can't measure how much rain falls on the planet earth in a 24 hour period you can not predict weather conditions 200 years from now. So let's stop this crap it is not science.
The Shootist
1.5 / 5 (8) Feb 01, 2014
Waiting to mine precious metals and drill for hydrocarbons.

"Diamonds the size of plovers eggs"®
"Nuggets the size of your head"®
"Oil as sweet as Texas"™
runrig
4 / 5 (8) Feb 02, 2014
Climatology is garbage science. All past data has been altered. If you can't measure how much rain falls on the planet earth in a 24 hour period you can not predict weather conditions 200 years from now. So let's stop this crap it is not science.


No the science is fine thank you - for us that understand it.
Those of you, either glass-half empty types who throw the baby out with the bath water, or the ideologically challenged types that see "socialist conspiracy" to grab our "tax dollars" make me sick to the stomach. Exhibiting the worst of human nature - some of which shows in your post. Now please go away and spend a few months/years studying the science and endeavour to discover the depth of your ignorance. I thank you. Not. Goodbye and have a good life. I strongly object to your pooing on the same planet that I inhabit.
ubavontuba
2.2 / 5 (10) Feb 02, 2014
Disappearing snow increases risk of collapsing ice shelves in Antarctica
What "disappearing snow" are they talking about? Haven't they heard? Antarctic snow is increasing.

http://www.nature...8a0.html

MR166
2.5 / 5 (8) Feb 02, 2014
"Those of you, either glass-half empty types who throw the baby out with the bath water, or the ideologically challenged types that see "socialist conspiracy" to grab our "tax dollars" make me sick to the stomach."

Virtually every aspect of climate science is politically controlled. From the massaged raw data to the publishing of papers and funding of research, the climate "science" industry reeks of insider politics.
Maggnus
3.9 / 5 (7) Feb 02, 2014
Waiting to mine precious metals and drill for hydrocarbons.

"Diamonds the size of plovers eggs"®
"Nuggets the size of your head"®
"Oil as sweet as Texas"™

The Trollist is back!
runrig
4.3 / 5 (6) Feb 02, 2014

Virtually every aspect of climate science is politically controlled. From the massaged raw data to the publishing of papers and funding of research, the climate "science" industry reeks of insider politics.


MR166: That is only the case to those sad individuals whole filter all human motivations through the prism of politics.
Maggnus
4.3 / 5 (6) Feb 02, 2014
What "disappearing snow" are they talking about? Haven't they heard? Antarctic snow is increasing.
That was actually a good cite Uba - it's just to bad it talks about something completely different than what this article is talking about.
This article is talking about the loss of snow cover on floating ice shelves as a result of a warming climate:
"as global warming reduces their snow cover"
whereas your cite talks about an increase in snow accumulation on the East Antarctica ice sheet (the ice sheet is on land) and speculates that IF this same degree of accumulation is occurring over the whole of the continent, then the amount of contribution by Antarctic ice sheet melt may be less than thought, by as much as 1 - 1.2mm/year. In 1991 (the year of the article) this made a lot of sense, especially in light of the spotty knowledge of snow accumulation over the rest of the continent at that time. Too bad it's so badly outdated.
Its that comprehension thing again Uba.
Maggnus
3.9 / 5 (7) Feb 02, 2014
Virtually every aspect of climate science is politically controlled. From the massaged raw data to the publishing of papers and funding of research, the climate "science" industry reeks of insider politics.
We already know your take on the conspiracy. "I don't agree with the politics so the science is wrong". Idiocy.
ubavontuba
1.8 / 5 (5) Feb 02, 2014
What "disappearing snow" are they talking about? Haven't they heard? Antarctic snow is increasing.
That was actually a good cite Uba - it's just to bad it talks about something completely different than what this article is talking about.
So maybe you think snow only falls on the continent?

I didn't know snow was so sentient!

gregor1
2.6 / 5 (5) Feb 02, 2014
Sorry but Icesat shows the snow accumulation too.
From the abstract-
"During 2003 to 2008, the mass gain of the Antarctic ice sheet from snow accumulation exceeded the mass loss from ice discharge by 49 Gt/yr (2.5% of input), as derived from ICESat laser measurements of elevation change. The net gain (86 Gt/yr) over the West Antarctic (WA) and East Antarctic ice sheets (WA and EA) is essentially unchanged from revised results for 1992 to 2001 from ERS radar altimetry."
http://wattsupwit...-losses/
gregor1
2.3 / 5 (6) Feb 02, 2014
The catastrophic climate change movement is intensely political. It is pretty much the same as the eugenics movement which also claimed scientific consensus to justify its existence. Eugenics though didn't start its own gold rush like CAGW which consumes around $1 billion per day, money that could be well spent on real environmental issues. But then it's proponents never did really care about the environment. http://www.michae...ous.html
http://joannenova...he-room/

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