Polar Ice sets new minimum

[BrickFielder]

Last year I watched and posted a 'meltwater surge' flow out through McMurdo sound and off into the southern oceans, past N.Z. and on into equitorial waters. No one 'in the know' reported anything exceptional so I decided it had to be me being daft. This year once again a huge 'channel' is calved out through McMurdo sound (4 to 6 weeks earlier than last year) and a cold water anom. is there at the front of Ross in the southern oceans (again).

A large area of cold water like that will set up a pressure pattern across the southern half of the Pacific. I am wondering if this would force the trade winds back into a La nina pattern and into a positive OLR anomaly phase cooling the earth?

[Gray-Wolf]

A large area of cold water like that will set up a pressure pattern across the southern half of the Pacific. I am wondering if this would force the trade winds back into a La nina pattern and into a positive OLR anomaly phase cooling the earth?

The deep water cold upwelling that ended the last El-Nino (and started this La Nina) coincided with the arrival of this meltwater surge last year (and I posted as much) but of course who am I to think such heresy?

Any 'cooling' would obviously be a short lived event (much as our wet summer this time from the meltwater flowing in the arctic drift) but it would be sdomething to watch for.

[jethro]

The deep water cold upwelling that ended the last El-Nino (and started this La Nina) coincided with the arrival of this meltwater surge last year (and I posted as much) but of course who am I to think such heresy?

Any 'cooling' would obviously be a short lived event (much as our wet summer this time from the meltwater flowing in the arctic drift) but it would be sdomething to watch for.

Not too sure how that would work, I've never heard or read anything, anywhere which would suggest meltwater would cause La Nina, certainly not on the scale we are talking about here; it would require a colossal amount of cold water surely?

http://www.physicalgeography.net/fundamentals/7z.html

[Gray-Wolf]

Not too sure how that would work, I've never heard or read anything, anywhere which would suggest meltwater would cause La Nina, certainly not on the scale we are talking about here; it would require a colossal amount of cold water surely?

http://www.physicalgeography.net/fundamentals/7z.html

And this is the point. Enough water to raise global sea levels by 5 t 7cm at least and we'd have heard of that surely? or would we??

If you think back over the last 3 years we've had Antarctic revalations by the score. All centered around meltwater phenomina. Ice lakes heaving up 2 miles of ice tens of metre's and the slumping as the lakes drain. Sub ice rivers and streams revealed by the latest radar imaging. Snow melt over 1 mile up the fringes of Ross. No talk of where all of this 'moving waters' are 'moving' to. Then last years sea temp. anoms. (I wish you'd have followed my 'tracking' of the meltwater surges progress! you'd have seen it as 'real')

I'd say that folk who know their coasts need to watch the 'tide marks' this year and see if 'calm tides' bring exceptionally high tide marks. Only individual observations would prove useful if the authorities are sitting on some very disturbing news.

Pop up to the weather section as I've just posted some more insane ramblings up there and then ,if you wish, come back to me!

[jethro]

And this is the point. Enough water to raise global sea levels by 5 t 7cm at least and we'd have heard of that surely? or would we??

If you think back over the last 3 years we've had Antarctic revalations by the score. All centered around meltwater phenomina. Ice lakes heaving up 2 miles of ice tens of metre's and the slumping as the lakes drain. Sub ice rivers and streams revealed by the latest radar imaging. Snow melt over 1 mile up the fringes of Ross. No talk of where all of this 'moving waters' are 'moving' to. Then last years sea temp. anoms. (I wish you'd have followed my 'tracking' of the meltwater surges progress! you'd have seen it as 'real')

I'd say that folk who know their coasts need to watch the 'tide marks' this year and see if 'calm tides' bring exceptionally high tide marks. Only individual observations would prove useful if the authorities are sitting on some very disturbing news.

Pop up to the weather section as I've just posted some more insane ramblings up there and then ,if you wish, come back to me!

I have followed it.

I think I'm getting to the point with all of this of taking time out to ponder and read some more. I've spent lord knows how much time reading and researching as much as I can but I think I can honestly say, I'm more confused than I was at the beginning. I began this journey from a purely professional point of view, most of my work involves historic parkland and I was not only heartily sick of English Heritage telling me I couldn't plant this or that species of tree as it wouldn't survive in our AGW moderated climate but also genuinely concerned that I could end up responsible for wrecking or at least not safe guarding, what is to me, an important part of our heritage.

So, I spent lots of time reading and went from a believer in AGW to a questioner, I had fairly lucid questions and doubts as to why the AGW theory didn't stand up to scrutiny. Now, I haven't the faintest idea. So little of what I read answers my questions, so much leads to ever more questions. Gut reaction is that Mother Nature is still very much, firmly in control. Gut reaction also tells me changes are afoot, some probably surprising ones but do I believe all these changes are down to warming atmosphere or more importantly, our contribution to that? No, I don't. Could I give you a valid, scientific reason or argument for the changes you see in Antarctica? Not one that would make much sense outside of my head.

It's like trying to do a 10,000 piece jigsaw puzzle, without the picture.

[Gray-Wolf]

Hi Jethro!

I do truely empathise with your position and I know Mother nature is still in control. It is her 'control' that is trying to keep things 'balanced' and it will be Her that causes any dramatic 'jump' to balance out the planets heat budget.

We may have forced the situation but she will find her 'point of balance' again no matter how far we force things out of kilter.

E.A.I.S. is an extremely fascinating place for me. Yet again we are treated to our science saying "that will not happen" only for the data to then show it happening (upland snow melt as an easy 'for instance').

Two years ago folk were telling me not to waste my time on concerns for the Continent but it would seem that they were wrong as the data amasses and attests to the 'dynamic' nature of this supposedly 'slumbering giant'

[BUSHY]

The upwelling of cold deep water at McMurdo is because of the nature of the coast quite normal.

[Gray-Wolf]

The upwelling of cold deep water at Mcmurdo is because of the nature of the coast quite normal.

Now without wishing to parade either your, or my, ignorance you will have to expand on that BUSHY.

I'll post a couple of images first and then we can explore the geomorphological reasons for both my concerns of outflow and your understanding of B.A.U. outflow

I appologise for the 'thumbnail' nature of the above but it serves our purpose well. As you can see Ross Sea overlies a sedimentary delta. The delta has built up from both fluvial deposits (whilst Antarctica was ice free) and glacial deposits (in the form as 'terminal moraine' from the ice shelf edge as it pushes backwards and forwards.

Another image.

again, appologise for the thumbnail nature of the image (I'm sure paintbox will 'expand' it for you to a useful size).

Again we can see the shallow nature of the Ross sea bed.

Where does you 'deep' upwelling originate from in such a shallow shelf environment?

How does your 'deep upwelling' manifest when the flow from ,and through, Mcmurdo sound is out into the southern ocean?

I am willing to learn ( and be corrected) in my understanding that Mcmurdo sound is the primary outlet for ALL of the E.A.I.S.'s summer outflow (and in a normal summer there is plenty of 'free water' around the sound to 'outflow') and how your 'deep upwelling ' is generated in this area.

For the 5 years I have had a casual interest in events across Ross I have witness a year on year increase on both the scale of the outflow from the Ross sea into the southern ocean (as picked out by cold water anoms as they flow onto N.Z. and beyond) but also their penetration into the Pacific proper. Do you have information of a 'cyclical' intensity change in outflow (remember the south is supposed to be cooling leading to a lessening of melt surely???).

The giant Bergs off south island (N.Z.) last year were the first witnessed in 80 years (and far bigger than those 80 years ago) so what 'current' had driven them there (as opposed to the normal 'workings of the continent')?

Love to hear your take on things.

Ian.

[jethro]

What was going on down there 20, 30, 40 years ago? Is there an historical context in which to place the current situation?

[BUSHY]

Wind and currents may push the ice northward into the Ross Sea, stirring up cold bottom currents that spill into the ocean basins of the world. link

[Gray-Wolf]

Must we always trawl into areas you feel 'safe' due to lack of reliable data? How do you think we would best achieve a conclusion if all you wish to do is stall the discussion by running into these 'safe' areas?

20,30,40 years ago we were not evacuating South sea islands due to sea level increases, 20,30,40 years ago we hadn't seen the bare head of Kilimanjaro, 20,30,40 years ago we had more than the crumb of Multiyear ice in the arctic over summer, 20,30,40 years ago LarsenB was intact,the front of Ross wasn't Calving and Pine Island (and it's surrounding area) still had ice shelf protection.20,30,40 years ago Urtsi was still locked in his 5,000yr old refrigerator atop of the Alps,20,30,40 years ago many of the worlds glaciers were still reasonably complete.20,30,40 years ago sea levels were lower.20,30,40 years ago China was a mainly agrarian society producing methane from Paddy fields and not CO2 from power stations.20,30,40 years ago we used to have snow on a regular basis over winter in lowland Britain.20 ,30,40 years ago I used to look far cuter!!!

My concerns are 'concerns' (to me at least) and as such I find it hard to understand why folk don't share them (with the evidence they have at their disposal).

I have always been a joker ,though my wit may not to be to the taste of all, but I have not,historically, been a worrier and so when I find cause enough to be concerned I struggle to understand those who easily dismiss these concerns without reason (enough to calm my concerns).

[Gray-Wolf]

Wind and currents may push the ice northward into the Ross Sea, stirring up cold bottom currents that spill into the ocean basins of the world. link

We are discussing the current events (past 5yrs?) and not what someone has cared to post about the historical workings around the sound (as is the nature of 'Wiki'). The cold water that used to sink into the worlds ocean basins took many years to complete it's global trek. We are taking about events that take a couple of months from Mcmurdo to equator (as a giant rush of water would) and we are also wondering about the impact on global sea levels if such a 'flow' is occuring over the southern summer.

It is not an event easy to hide/mistake so ,yet again, a short period of time will reveal all.

[BUSHY]

There is no lack of data GW. The antartic has been cooling for decades and sea-ice area has been increasing so where is this melt water supposed to be coming from all of a sudden? And what dramatic sea level increases. read this 2006 paper

[jethro]

Must we always trawl into areas you feel 'safe' due to lack of reliable data? How do you think we would best achieve a conclusion if all you wish to do is stall the discussion by running into these 'safe' areas?

20,30,40 years ago we were not evacuating South sea islands due to sea level increases, 20,30,40 years ago we hadn't seen the bare head of Kilimanjaro, 20,30,40 years ago we had more than the crumb of Multiyear ice in the arctic over summer, 20,30,40 years ago LarsenB was intact,the front of Ross wasn't Calving and Pine Island (and it's surrounding area) still had ice shelf protection.20,30,40 years ago Urtsi was still locked in his 5,000yr old refrigerator atop of the Alps,20,30,40 years ago many of the worlds glaciers were still reasonably complete.20,30,40 years ago sea levels were lower.20,30,40 years ago China was a mainly agrarian society producing methane from Paddy fields and not CO2 from power stations.20,30,40 years ago we used to have snow on a regular basis over winter in lowland Britain.20 ,30,40 years ago I used to look far cuter!!!

My concerns are 'concerns' (to me at least) and as such I find it hard to understand why folk don't share them (with the evidence they have at their disposal).

I have always been a joker ,though my wit may not to be to the taste of all, but I have not,historically, been a worrier and so when I find cause enough to be concerned I struggle to understand those who easily dismiss these concerns without reason (enough to calm my concerns).

Look, GW you don't know me from Adam, you could walk past me in the street and not know, so why oh why do you endlessly make personal assumptions about me and my character? "Safe zones" my a**e.

Ask any scientist in the world on how to make assessments on anything and they will tell you, in order to judge anomolies, you first need to establish a base-line of normality. I've followed your threads, read your concerns and never commented because I don't know enough. You obviously know a great deal more than I, so is it too much to ask for you to post links/papers detailing the history of the area and our knowledge to date? If you just want a thread where you can raise concerns and alarm, then fine, I'll butt out. But if you want to discuss with others, discover whether your alarm/concern is proportional to the threat, then that will entail dialogue which usually includes questions.

[Gray-Wolf]

BUSHY, with the greatest of respect we are talking about the last 5 years (and the data released over that time period) and not pre-2002 (as in all the documentation in the link posted)

LarsenB didn't go until feb 2002 (and the rapid acceleration of the glaciers to the rear of it), NASA had only started compiling/collecting the data for the upland ice melt across the Continent in 2002. The measurements of the rising and falling of sections overlying sub ice sheet lakes wasn't even an ongoing in 2002. The Radar plotting of the 'rucking' in the ice behind Ross hadn't been done in 2002. I could go on but I'm sure you get the picture.

Even the measurements of 'increased snowfall' as gauged by height above sea level of 'trig points' may well be suspect as the data could be culled over an area of active hydro uplift (which could be over 25m 'off the mark') and so until we have proof that the pre 2002 is not flawed it may be wise to dismiss it.

So , post 2002 ( to present) what do we have? Giant chunks of the fringing shelf around the Peninsula gone. Glaciers around W.A.I.S. flowing up to 10 times faster than previous measurements.Sub ice lakes heaving up 2 miles of ice up to 25m over a 2 year period and draining over 18 months) Summer melting of snow up to 1 mile up in the mountains fringing the Ross embayment. The Destabilisation of the Pine glacier area. Large 'outflows' into the southern ocean and on into the Pacific from Dec through April.

Which data is more valid? Current or historical, flawed data?

[BUSHY]

I don't know how you can just dismiss all previous, even relatively current data as flawed but oh well -- It seems to me that this current scare of yours arises from the discovery of more sub-glacier lakes using modern satellite based technology. The total estimated amount of water locked up in these lakes if all was released at once would result in the sort of sea level rises that that you have asserted have been suppressed by the ( whoever has that dubious power )

That is of course not possible and has not happened nor will it in the foreseeable future. These lakes are locked up securely under miles of ice and although the occasional draining of water has occurred the bulk of it will remain where it is as long as there is an ice cap on the antarctic. The lifting and slumping of ice over some lakes is quite normal and well documented. This occurs as the ice moves over deep water bodies and becomes floating ice as it crosses the water, usually preceded by a slumping as the ice moves down the sloping ground toward the lake and a lifting as it gets to the far side. In case anyone wants to know, the liquid water exists only because of geothermal warming and the enormous pressure exerted by the overlying ice that decreases the freezing point of the water.

[Gray-Wolf]

When talking with the guys at Mcmurdo 18 months ago they allayed my fears about the Ross embayment by telling me that until they saw similar events to those on the

Peninsula prior to it's disruption we would be fine. 6 months later we were treated to the NASA images of the snow melt in the range of mountains that fringe 'The Ross' in just the sort of areas that would lead to a 'loosening' of the ice/bedrock contact at the 'coastline'. At the same time there was a programme of seismometer deployment (with a couple deployed over 'my crack'....see other thread!) to check the grumbles and groans of the shelf itself. Seeing as this was less than 2 years ago I wouldn't expect any data released from this study yet but that may prove to be interesting read I feel. The other 'phenomena was 'meltwater pooling' on the shelf (which was visible in areas last year) and I will endeavour to post some images in Jan. when the pools have reformed.

In short most of the supposed 'reassurances' that were given just gave rise to more concerns as each individual phenomena became apparent in the areas that you would expect to see them!

The other point is that one of the heads of dept. was giving out the reassurances whilst the data showing these events taking place was in the station. Is this just poor communication or something else?

[Gray-Wolf]

Scientists: Antarctic ice sheet thinning

HOUSTON, Texas (Reuters) -- A Texas-sized piece of the Antarctic ice sheet is thinning, possibly due to global warming, and could cause the world's oceans to rise significantly, polar ice experts said on Wednesday.

They said "surprisingly rapid changes" were occurring in Antarctica's Amundsen Sea Embayment, which faces the southern Pacific Ocean, but that more study was needed to know how fast it was melting and how much it could cause the sea level to rise.

The warning came in a joint statement issued at the end of a conference of U.S. and European polar ice experts at the University of Texas in Austin.

The scientists blamed the melting ice on changing winds around Antarctica that they said were causing warmer waters to flow beneath ice shelves.

The wind change, they said, appeared to be the result of several factors, including global warming, ozone depletion in the atmosphere and natural variability.

The thinning in the two-mile- thick ice shelf is being observed mostly from satellites, but it is not known how much ice has been lost because data is difficult to obtain on the remote ice shelves, they said.

Study is focusing on the Amundsen Sea Embayment because it has been melting quickly and holds enough water to raise world sea levels six meters, or close to 20 feet, the scientists said.

"The place where the biggest change is occurring is the Amundsen Sea Embayment," said Donald Blankenship of the University of Texas Institute for Geophysics.

"One, it's changing, and two, it can have a big impact," he said in a Webcast with a number of conference participants.

Other parts of the continent also were losing ice, he said, but generally not as quickly.

Source: CNN, POSTED: 4:49 p.m. EDT, March 29, 2007

Just as an add on to the above. Many things in many areas of Antarctica are changing rapidly all of which will lead to rapid sea level alterations and a catastrophic impact on the both our 'modern world' and the millions in coastal areas of the developing world.

Let us not forget that Ross is also being attacked from the front as well as from the rear (via meltwater penetration through the moulins and down to the base)Big lakes detected under Antarctica

WASHINGTON (Reuters) -- Lasers beamed from space have detected what researchers have long suspected: big sloshing lakes of water underneath Antarctic ice.

These lakes, some stretching across hundreds of square miles, fill and drain so dramatically that the movement can be seen by a satellite looking at the icy surface of the southern continent, glaciologists reported in Thursday's editions of the journal Science.

Global warming did not create these big pockets of water -- they lie beneath some 2,300 feet of compressed snow and ice, too deep to be affected by temperature changes on the surface -- but knowing how they behave is important to understanding the impact of climate change on the Antarctic ice sheet, study author Helen Fricker said by telephone.

About 90 percent of the world's fresh water is locked in the thick ice cap that covers Antarctica; if it all melts, scientists estimate it could cause a 23-foot rise in world sea levels. Even a 39-inch sea level rise could cause havoc in coastal and low-lying areas around the globe, according to a World Bank study released this week.

"Because climate is changing, we need to be able to predict what's going to happen to the Antarctic ice sheet," said Fricker, of the Scripps Institute of Oceanography and the University of California, San Diego.

"We need computer models to be faithful to the processes that are actually going on on the ice sheet," she said. At this point, computer models do not show how the subglacial water is moving around.

To detect the subglacial lakes, Fricker and her colleagues used data from NASA's ICESat, which sends laser pulses down from space to the Antarctic surface and back, much as sonar uses sound pulses to determine underwater features.

The satellite detected dips in the surface that moved around as the hidden lakes drained and filled beneath the surface glaciers, which are moving rivers of ice.

"The parts that are changing are changing so rapidly that they can't be anything else but (sub-surface) water," she said. "It's such a quick thing."

"Quick" can be a relative term when talking about the movement around glaciers, which tend to move very slowly. But one lake that measured around 19 miles by 6 miles caused a 30 foot change in elevation at the surface when it drained over a period of about 30 months, Fricker said.

The project took observations from 2003 through 2006 of the Whillans and Mercer Ice Streams, two of the fast-moving glaciers that carry ice from the Antarctic interior to the floating ice sheet that covers parts of the Ross Sea.

Source: CNN, POSTED: 10:49 a.m. EST, February 16, 2007

So if we loose the ice dams we start to loose these vast reserviors into the southern oceans. The loss of the fringing 'shelves' around the East Antarctic Ice Sheets are what we need concern ourselves with and, it would appear, their stability is already being compromised.

[Gray-Wolf]

I also dug this out by a German scientist (the one who has the 'outer limit' of the IPCC report on expected sea level change and he isn't a happy bunny about the 'watered down' version of the final report;

The report is also expected to include some kind of proviso that says things could be much worse if ice sheets continue to melt.

The prediction being considered this week by the IPCC is "obviously not the full story because ice sheet decay is something we cannot model right now, but we know it's happening," said Stefan Rahmstorf, a climate panel lead author from Germany who made the larger prediction of up to 55 inches of sea level rise. "A document like that tends to underestimate the risk," he said.

"This will dominate their discussion because there's so much contentiousness about it," said Bob Corell, chairman of the Arctic Climate Impact Assessment, a multinational research effort. "If the IPCC comes out with significantly less than one meter (about 39 inches of sea level rise), there will be people in the science community saying we don't think that's a fair reflection of what we know."

In the past, the climate change panel didn't figure there would be large melt of ice in west Antarctica and Greenland this century and didn't factor it into the predictions. Those forecasts were based only on the sea level rise from melting glaciers (which are different from ice sheets) and the physical expansion of water as it warms.

But in 2002, Antarctica's 1,255-square-mile Larsen B ice shelf broke off and disappeared in just 35 days. And recent NASA data shows that Greenland is losing 53 cubic miles of ice each year -- twice the rate it was losing in 1996.

And then there is more evidence of how much colder the Antarctic is becoming (not)

http://www.70south.com/latest-antarctic-ne...-of-collapsing/

[Chris Knight]

And then there is more evidence of how much colder the Antarctic is becoming (not)

http://www.70south.com/latest-antarctic-ne...-of-collapsing/

Tell me who to donate it to and I'll send them a tenner for a gallon of creosote (or whitewash if that is more aesthetically pleasing)

[Gray-Wolf]

I'm slowly amassing daily images of the Ross embayment to see how the ice is being 'flushed away' and the first few images clearly show that it is a flow from the glaciers to the West of Mcmurdo sound that is driving things. you can already see from the shape of the hole that it has to be from this area and from some of the bergs that are being snapped in two it appears to be quite a busy flow. I'm sure by the time I have 2 weeks worth of images you'll all be left in no doubt that it is water, and not wind, that is driving this gash.

More later

EDIT: I didn't spot things quick enough but it seems the flow grew to the point of ice disruption on the 27th of Nov. I wonder what the sea temp anoms look like around this time?

[Bobby]

http://www.mercopress.com/vernoticia.do?id...mp;formato=HTML

Fleming Glacier in Antarctica shows signs of receding.

Not sure if you've already talked about this but it's interesting...

[BrickFielder]

What is interesting is that sea ice is receeding in areas where I would not have expected it to during la nina conditions. Studies have recently shown that under la nina conditions ice extents should grow in the southern pacific and shrink in the southern atlantic.

la nina and el nino rearrange antarctic sea ice

Any large amounts of ice melt are likely to cool surface waters such that an enhanced a cooling of mid-latitude Southern Ocean surface water occurs, this can be subducted and advected through the eastern boundary current to form the water at the base of thermocline in the eastern equatorial Pacific. So any melt water in the regions you are talking are likely eventually to bring back la nina conditions, I think. In theory prolonged la nina can cool surface temperatures by raising OLR (outgoing long wave radiation) so perhaps this is some sort of negative feedback mechanism. I am thinking the intensity of the swing between atlantic and pacific is some what modified by feedback through the north pole (i.e. la nina and el nino affect the speed and amount of sinking cold water towards the arctic) with this modification perhaps begining to fail. This is all wild conjecture but it does look like an oscillation of sorts had become a little unbalanced and time will tell whether it balances again and how, or even if I am close to being right for that matter.

Ocean Currents

[Gray-Wolf]

http://www.sciencedaily.com/releases/2007/...71211233433.htm

obviously Greenland suffered along with the Arctic this year. To think of all the reassurances I have received on here (N.Weather) about the sanctity of the Greenland ice sheet whilst it's melting under our noses!

I also heard on the radio that the latest models run (with this summers data included) puts the 'ice free Arctic' well into my time line (5 to 6 years). I wonder if it'll make any difference to how my concerns over Antarctica (the real baddie) are received????

I'll try and find the paper.

[Gray-Wolf]

http://www.sciencedaily.com/releases/2007/...71211233433.htm

obviously Greenland suffered along with the Arctic this year. To think of all the reassurances I have received on here (N.Weather) about the sanctity of the Greenland ice sheet whilst it's melting under our noses!

I also heard on the radio that the latest models run (with this summers data included) puts the 'ice free Arctic' well into my time line (5 to 6 years). I wonder if it'll make any difference to how my concerns over Antarctica (the real baddie) are received????

I'll try and find the paper.

Blinkin' fast edit!!!!

http://www.sciencedaily.com/releases/2007/...71210094332.htm

found this though. Seems our little world was entering meltdown before 'global dimming' stepped in. 'Natural cycle' anyone?????