Wilkins Ice Shelf breaking

[biffvernon]

BAS are reporting a major break on the Wilkins Ice Shelf

Professor Vaughan, who in 1993 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, says,

"Wilkins is the largest ice shelf on the Antarctic Peninsula yet to be threatened. I didn't expect to see things happen this quickly. The ice shelf is hanging by a thread – we'll know in the next few days or weeks what its fate will be."

more

[NL]

Was mentioned on BBC Breakfast today and they said that its was yet further

evidence of global warming but will not increase sea level rise as it sits on water

and not antarctica.

[Gray-Wolf]

If you page back through this ,and other, thread's you'll find that the 'junction' between sea and land is a very stressed place when sea levels rise allowing for breaks at the juncture as the winter strom swells place further stresses on that junction.

With sea ice so thin (as it rebuilds for the winter) any autumn storm swell pounds the coast and many shelves have been lost in march over the past years.

[biffvernon]

Film of Wilkins:

http://video.google.com/videoplay?docid=-9...h&plindex=6

[Guest mycroft]

Gents

Forgive me but could this not be a natural event,that is too say may be the ice shelf in that particular area has reached it maximum size and will grow again.surely an ice shelf will only be able to reach a certain size within the confines of the climatic conditions present.

[Climate Man]

This ice sheet may be the largest on the Pensinsula but is, in Antarctic terms, quite small. It is well know that this part of the Antarctic is warming whilst others are cooling. Normal, non-event, in my book.

[BLAST FROM THE PAST]

There is no impending disaster. This ice break off constitutes 0.004% of Antarctic ice. All the evidence in the antarctic at present is of 'overall' ice growth.....and that seems to be affecting the SH seasons.....can anyone pinpoint widespread record heat down there this summer? No but you'll see reports of cool summer and early snowfalls.

BFTP

[millennia]

There is no impending disaster. This ice break off constitutes 0.004% of Antarctic ice. All the evidence in the antarctic at present is of 'overall' ice growth.....and that seems to be affecting the SH seasons.....can anyone pinpoint widespread record heat down there this summer? No but you'll see reports of cool summer and early snowfalls.

BFTP

Antarctic ice reached a record last October, based on Satellite images which admittedly only go back to 1979. However it is now the start of their Autumn, the area around the break that happened only a few weeks ago has now refrozen and the ice pack is currently 60% AHEAD of it's normal freeze rate for this time of year. The graph below is the 800 pound gorilla in the room for the IPCC - the difference between the end of the Southern summer in 1980 (when the "consensus" of scientists thought we were going into an new Ice Age) and this month is an increase of some 3 million sq km and although a small time to make assumptions on (although that never stopped Gore) the 29 year trend is up. Of course now we get the "climate change not global warming" brigade running around trying to justify how man has made both the world warmer and Antarctica colder (and produced a record breaking cold NH winter) - except all the satellite data states there is absolutlely no warming trend since 1979, and the slight warming trend to 1998 has been totally reversed to 2008 and now we look to be heading back to where we were in the 70s again.

[Devonian]

Antarctic ice reached a record last October, based on Satellite images which admittedly only go back to 1979. However it is now the start of their Autumn, the area around the break that happened only a few weeks ago has now refrozen and the ice pack is currently 60% AHEAD of it's normal freeze rate for this time of year. The graph below is the 800 pound gorilla in the room for the IPCC - the difference between the end of the Southern summer in 1980 (when the "consensus" of scientists thought we were going into an new Ice Age) and this month is an increase of some 3 million sq km and although a small time to make assumptions on (although that never stopped Gore) the 29 year trend is up. Of course now we get the "climate change not global warming" brigade running around trying to justify how man has made both the world warmer and Antarctica colder (and produced a record breaking cold NH winter) - except all the satellite data states there is absolutlely no warming trend since 1979, and the slight warming trend to 1998 has been totally reversed to 2008 and now we look to be heading back to where we were in the 70s again.

So, you're saying one strand of evidence (a year of more ice than average in the SH) disproves AGW but wrt to the ridiculously low minimum ice area in the NH last summer, to continued high global temperatures, ever increasing greenhouse gas emissions/concentrations and other human caused climate changing changes to the biosphere you say nothing?

[BLAST FROM THE PAST]

Evidence is mounting that world food supplies are becoming stretched, prices are beginning to soar. Example how much grain is in the US? Only enough to cover one year, they don't mass produce and store anymore and when suddenly they have a very damaging growing season and supplies become less prices soar. Some may say so what? Anyone notice the price of eggs lately? The price of pork/bacon lately? The price of butter lately? etc etc All the stuff that comes from animals fed on.......grain. Things look like only getting worse this year after the 'widespread' damaging cold in the NH. This isn't a rant...keep watching and look around.

IMO there is more to come. Anarctica will post a record ice maxima this year, we are in a perturbation cycle of La nina dominance timed with a solar minima that could 'at least' match a Dalton scenario.

BFTP

[Devonian]

Scientists did some research under what was the Larsen B ice shelf and found evidence that it been there for at least 10, 000 years. These ice shelves grow to that balance point between flow and wave/temperature action - and if Larsen B is anything to go by, that balance point hasn't changed much - until now... I don't see any evidence that they have undergone cycles of growth and destruction until now when they are being destroyed and showing no sighs of re growth, but, if it exists please present it.

Is the Larsan B shelf re growing?

[millennia]

Evidence is mounting that world food supplies are becoming stretched, prices are beginning to soar. Example how much grain is in the US? Only enough to cover one year, they don't mass produce and store anymore and when suddenly they have a very damaging growing season and supplies become less prices soar. Some may say so what? Anyone notice the price of eggs lately? The price of pork/bacon lately? The price of butter lately? etc etc All the stuff that comes from animals fed on.......grain. Things look like only getting worse this year after the 'widespread' damaging cold in the NH. This isn't a rant...keep watching and look around.

BFTP

This is the great scandal - while everybody is fretting about credit crunches (despite record bank profits) and constant global warming drivel (I've put in an offical complaint to the BBC this week after the ridiculous 30 second slot reinforcing fears of ice loss in Antarctica with no balancing material) they are missing a MUCH bigger crisis developing with rainforests being cut down to plant palm oil for bio fuels, maize crops being turned over to bio fuels, and a potential for dramatic loss of production due to bad weather. We are screwing with the planet in the name of environmentalism and risking a starving population. Two back to back catastrophic grain harvests in the major NH producing nations would spark a level of food crisis that could also increase tensions and even spark a war.

THIS IS A LOT MORE IMPORTANT THAN A BLOODY BIT OF ICE FALLING OFF THE TIP OF ANTARCTICA - WAKE UP!!!

[Devonian]

This is the great scandal - while everybody is fretting about credit crunches (despite record bank profits) and constant global warming drivel (I've put in an offical complaint to the BBC this week after the ridiculous 30 second slot reinforcing fears of ice loss in Antarctica with no balancing material) they are missing a MUCH bigger crisis developing with rainforests being cut down to plant palm oil for bio fuels, maize crops being turned over to bio fuels, and a potential for dramatic loss of production due to bad weather. We are screwing with the planet in the name of environmentalism and risking a starving population. Two back to back catastrophic grain harvests in the major NH producing nations would spark a level of food crisis that could also increase tensions and even spark a war.

THIS IS A LOT MORE IMPORTANT THAN A BLOODY BIT OF ICE FALLING OFF THE TIP OF ANTARCTICA - WAKE UP!!!

No need to shout.

This is a climate forum. Climate is what interests me and those who post here. Climate change (man made or not) is also on topic.

However I am aware of the worlds other problems, it's just this isn't an the place to discuss them without going OT. Fwiw, I think bio fuels are a environmental disaster, perhaps even a scam, promoted by a dimwitted US president to help American farmers and improve his image. But, that's OT.

[BLAST FROM THE PAST]

Is the Larsan B shelf re growing?

Dev

Very likely to. Read this report, the ice shelves on the peninsula are not very old at all and were not there in the recent past.

here

I take this as the peninsula is of little consequence in the overall picture and is exposed to natural variation.

BFTP

Edited March 6, 2009 by pottyprof

[Devonian]

Is the Larsan B shelf re growing?

Dev

Very likely to.

Nice confusion between Larsen A and B that WCR link you posted is. Larsen A is further north, and disintegrated in 1995. The further north you go the warmer it is going to be and the less permanent/stable ice shelves will be and the more open to destruction by a warming.. We don't after all, see ice shelves in the Falklands.

[SnowBear]

So the Larsen B break up couldn't be just the final stages of the pull out of the last ice age 10000 years ago then?

BAS say themselves that the data available is not over a long enough period to be able to draw any concrete conclusions (back to the International Geophysical Year of 1957-58 at best), small ice shelves have built and collapsed many times since the 10000yr point (Holocene boundary).

Larsen B may have been stable for 10000yrs but what was the tipping point for its current collapse? this last 30 years or sometime in the last 1000? 5000? I remember reading a nasa article on the Antarctic and they said it takes hundreds of years for the Antarctic to react and many events now will be triggered by events a long time ago.

Maybe the Mini Ice Age delayed the inevitable break up of Larsen A and B? If no Mini Ice Age perhaps it would have happened hundreds of years ago?

Perhaps Larsen just outgrew its sustainable size leading to a catastrophic failure of the whole shelf ?

Admittedly the changes in the warmer ocean currents etc have maybe added to the collapse, but who is to say those currents

would not have happened before if no Mini Ice Age?

How come even with the Larsen and surrounding area ice loss we see increasing cold and additional ice elsewhere on the continent?

Assuming is a dangerous thing, all the evidence is circumstantial, too many questions are left unanswered to say we have this as an exact science, or even got close to understanding it in my view.

[Devonian]

So the Larsen B break up couldn't be just the final stages of the pull out of the last ice age 10000 years ago then?

Or, maybe it was sound until recently then it catastrophically collapsed - at the same time as temperatures was rising a lot - no connection? Really?

BAS say themselves that the data available is not over a long enough period to be able to draw any concrete conclusions (back to the International Geophysical Year of 1957-58 at best), small ice shelves have built and collapsed many times since the 10000yr point (Holocene boundary).

Like which ones? If you say you can only go back to 1957 then you can only go back to 1957

Larsen B may have been stable for 10000yrs but what was the tipping point for its current collapse? this last 30 years or sometime in the last 1000? 5000? I remember reading a nasa article on the Antarctic and they said it takes hundreds of years for the Antarctic to react and many events now will be triggered by events a long time ago.

Maybe the Mini Ice Age delayed the inevitable break up of Larsen A and B? If no Mini Ice Age perhaps it would have happened hundreds of years ago?

Perhaps Larsen just outgrew its sustainable size leading to a catastrophic failure of the whole shelf ?

I think that is unlikely. There are lots of ice shelves, if the repeatedly built up and then just failed scientists would find the signs. The sings are Larson A (furthest north) is the least stable shelf (hardly surprising) and Larsens's B and C (further south) have been stable for along time because it's not been so warm as now for a long time?

Admittedly the changes in the warmer ocean currents etc have maybe added to the collapse, but who is to say those currents

would not have happened before if no Mini Ice Age?

How come even with the Larsen and surrounding area ice loss we see increasing cold and additional ice elsewhere on the continent?

Becuase the further south you go the colder it gets. Add moisture to the atmosphere, increase snowfall you'll get?

Assuming is a dangerous thing, all the evidence is circumstantial, too many questions are left unanswered to say we have this as an exact science, or even got close to understanding it in my view.

Assuming IS a dangerous thing. So, why wont you ask those other obvious question like 'is adding greenhouse gas to the atmosphere changing the temperature of said'? or 'Climate models predict the kind of changes that could cause what is happening, it is happening, perhaps the models are right?'. Why not ask those questions as well?

[Guest mycroft]

Who is to say it has?

Scientists did some research under what was the Larsen B ice shelf and found evidence that it been there for at least 10, 000 years. These ice shelves grow to that balance point between flow and wave/temperature action - and if Larsen B is anything to go by, that balance point hasn't changed much - until now... I don't see any evidence that they have undergone cycles of growth and destruction until now when they are being destroyed and showing no sighs of re growth, but, if it exists please present it.

Is the Larsan B shelf re growing?

So who's is to say the Larsen did not collapse 10,000 before! perhaps Larsen rebuilt over the previous 10,000 yr period.

We have idea how long these ice shelfs take to rebuild,and what tipping points are.The fact that Larsen broke up does not prove that it was down to AGW.Assuming something does not prove it

Edited March 28, 2008 by mycroft

[millennia]

So the Larsen B break up couldn't be just the final stages of the pull out of the last ice age 10000 years ago then?

BAS say themselves that the data available is not over a long enough period to be able to draw any concrete conclusions (back to the International Geophysical Year of 1957-58 at best), small ice shelves have built and collapsed many times since the 10000yr point (Holocene boundary).

Larsen B may have been stable for 10000yrs but what was the tipping point for its current collapse? this last 30 years or sometime in the last 1000? 5000? I remember reading a nasa article on the Antarctic and they said it takes hundreds of years for the Antarctic to react and many events now will be triggered by events a long time ago.

Maybe the Mini Ice Age delayed the inevitable break up of Larsen A and B? If no Mini Ice Age perhaps it would have happened hundreds of years ago?

Perhaps Larsen just outgrew its sustainable size leading to a catastrophic failure of the whole shelf ?

Admittedly the changes in the warmer ocean currents etc have maybe added to the collapse, but who is to say those currents

would not have happened before if no Mini Ice Age?

How come even with the Larsen and surrounding area ice loss we see increasing cold and additional ice elsewhere on the continent?

Assuming is a dangerous thing, all the evidence is circumstantial, too many questions are left unanswered to say we have this as an exact science, or even got close to understanding it in my view.

Assuming the ocean conveyer has a cycle of 1000 years, and the Medieval Warming Period ran from 1000 to 800 years ago (as well as the Roman Warming 2000 years ago), could it not just be part of a reaction to that? OK I throw my hands up, I'm not an Oceanographer, but my physics background tells me it takes more than the length of recent observations to significantly alter a heat engine with the inertia that the oceans have.

Let's face it, we don't have more than an inkling of how the ocean and atmosphere really work, and yet we are making economic decisions on the back of this lack of understanding.

[SnowBear]

Why cannot I ask a set of questions without being answered by questions?

Oh, maybe we don't know it all yet and we in effect don't have a clue and its all a guessing game. All circumstantial evidence and when we think we have answered something throws a spanner in the works. Like I said, this is not an exact science and I doubt we have even got close to understanding it.

[Thundery wintry showers]

I am a believer in GW, and for the most part AGW, but I'm afraid this news from Antarctica is far from being evidence of "global warming". As others have mentioned, the peninsula has warmed while the interior has cooled, and breakup and formation of ice happens all the time without the need for long-term temperature trends. It's certainly an important development, but far from being a disaster for, indeed, the ice is sea-based and not land-based, therefore should not cause sea level rises.

If you want evidence of global warming, the decline of the Arctic ice provides a much stronger case as the whole Arctic is warming and melting, as opposed to just one small part of it.

[BLAST FROM THE PAST]

TWS the Arctic ice breakup has not been proven to be AGW. Ocean current cycle has equal standing at the moment. Also prior to every ice age large or small melting of the northern ice cap has been the precursor every single time without fail.......cold NH winter wasn't it so one to look out for.

AGW is under threat by the solar minima we enter....CO2 continues to rise temps don't and indeed signs are of a fall. That matches solar cycle perfectly.

BFTP

[biffvernon]

Here's rarther more detail about the current situation on Wilkins:

http://nsidc.org/news/press/20080325_Wilkins.html

[Roger J Smith]

What I noted about this business was the rather unseemly way that pro-AGW scientists latched on to this event as though it was out of the ordinary and a danger sign of some kind. Surely large chunks of ice have broken away from Antarctica every year at about this time (the end of the southern summer) and I recall reading about huge ice "islands" spotted in low latitudes of the South Atlantic in the cold 19th century, so it was happening then too.

Meanwhile, references to global warming are becoming more ironic in North America where it just isn't warming up on schedule this spring, and huge piles of snow are widespread in eastern Canada, quite often by late March people are gardening in many of these places, this year, they are wondering when two or three feet of snow are going to melt in their back yards.

I'm sorry, but this is hardly a cherry-picking observation, it seems like a real reversal in the recent trend. Oddly enough, it may be feedback from that unusual melt in the arctic ocean last autumn, as I speculated here in forecast form last autumn. Apparently the natural system has ways of dealing with these anomalies, whether natural or not, at least for the time being.

I'll certainly say so if I come to believe there is an impending danger of larger meltdowns, but for now, it seems to me that the global climate system has stabilized. Western Europe and the northeast Atlantic remain winter-challenged to some extent, but that's the current set-up, things could change in your favour. I don't believe winter has gone away forever.

[Gray-Wolf]

http://nsidc.org/news/press/20080325_Wilkins.html

Pinched yer link Biffy!

If you look at the images from the 28th feb you can see no discernible difference in the surface of the shelf. Within 24hrs the whole block size of N.I. is smashed.

Either there was a humongous event that smashed the block [very unlikely as we have no reports of quakes etc from the world sensors] or the whole lot of ice was a riddled cancerous mess of house sized hollows and connecting chambers (like a crunchie bar) which just could not stand up to the motion of the ocean.

Do not think that this type of internal decay is confined to the peninsula though as radar evidence and sat measurements would have it that many of the 'drainage areas' from E. Antarctica show the same type of free water movement below the ice.

When you look at E. Antarctica remember that shot of Wilkins on feb 28 2008.......look the same don't they?

The MODIS suite allows all of us the same access to the images as BAS use and all of us to ,first hand, to follow the disintegration of the Antarctic Ice Sheet.

Edited March 29, 2008 by Gray-Wolf