From AAAS online:
Widespread Persistent Thickening of the East Antarctic Ice Sheet by Freezing from the Base
Abstract
An International Polar Year aerogeophysical investigation of the high interior of East Antarctica reveals widespread freeze-on that drives significant mass redistribution at the bottom of the ice sheet. While surface accumulation of snow remains the primary mechanism for ice sheet growth, beneath Dome A 24% of the base by area is frozen-on ice. In some places, up to half the ice thickness has been added from below.
These ice packages result from conductive cooling of water ponded near the Gamburtsev Subglacial Mountain ridges and supercooling of water forced up steep valley walls. Persistent freeze-on thickens the ice column, alters basal ice rheology and fabric and upwarps the overlying ice sheet, including the oldest atmospheric climate archive, and drives flow behavior not captured in present models.
- Received for publication 8 November 2010.
- Accepted for publication 18 February 2011.
- Robin E. Bell1,
- Fausto Ferraccioli2,
- Timothy T. Creyts1,
- David Braaten3,
- Hugh Corr2,
- Indrani Das1,
- Detlef Damaske4,
- Nicholas Frearson1,
- Thomas Jordan2,
- Kathryn Rose2,
- Michael Studinger5, and
- Michael Wolovick1
+ Author Affiliations
1Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.
2British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK.
3Center for the Remote Sensing of Ice Sheets, Kansas University, Lawrence, KS, USA.
4Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover, Germany.
5Goddard Earth Science and Technology Center, University of Maryland Baltimore County, MD, and NASA Goddard Space Flight Center, MD, USA.
I would think this might be driven solely by capillary action, where a liquid (super-cooled water) is siphoned upward against graivty between two closely spaced solids until it can freeze. Then this new ice is merely one of the solids and this process continues, never ending. Can’t you see something like that occurring?
““Rising sea levels present one of the biggest threats to civilisation as we know it,” says Tim”
Lucky for us 2010 is on target for a DROP in sea levels.
Hmmm .. we should look out for any suspiciously palindromic sequences in Antarctic ice core temperature reconstructions. For instance those arguing for a long continuation of the current interglacial point to similarities between it and the 4th interglacial back, just over 400 kyrs ago.
However I believe that frozen sea water does retain some salt. Snow by contrast is generally not salty. So salinity, plus entrapped plankton and particles, should identify ice frozen on from beneath.
So what does an ice core analyst do, toiling diligently in the lab on a long ice core, to check that the core section under analysis is really from snowfall, thus getting older with depth, and not sea ice from below and younger with depth?
Well there is a simple ad hoc solution, he/she should periodically lick the ice to taste if it is fresh or salty.
Hang on though – maybe not such a good idea. A certain scene from one of the Dumb and Dumber movies springs to mind…
I guess everyone has seen the latest spew from the liars at nasa:
http://www.nasa.gov/topics/earth/features/earth20110308.html
edgar
March 8, 2011 at 2:45 pm
Yup,
OMG! ts worse then we thought :0
@Martin webster
Why would it be getting thinner from the top when it’s not any warmer at the top? Of course, thinning glaciers are proxy for precipitation, not temperature. But, the precip was already near zero, there.
@Gary Young Mount
Leave it the French to design a passenger airplane that crashes if the pitot tubes freeze up.
So Ok I’ll be the guinea pig. Now all this ice that is growing underneath the Antarctic ice; this is ordinary regulation H2O type ice is it not. Normal ice is made from normal H2O water which is a liquid substance, but it can also be made from gaseous H2O which is a gaseous substance; but in any case to make ice you generally need some source of H2O molecules: oodles of them; megatons of them in fact to grow much thickness of underbelly ice on Antarctica..
So ‘splain me the origins of this H2O, underneath the ice, could it be leaking out of the oceans, and up rivers somehow underneath the ice by some sort of caterpillary action ? Izzat possible ?
I should hasten to add, that I do believe the story; I’m just curious as to how it rains or snows under so much ice.
George E. Smith,
The water is ice that has melted at the earth/ice interface from geothermal heating. That water collects in low spots. Thus Lake Vostok. This refreezing of this melted ice is apparently the result of more heat being conducted through the insulating ice sheet. Either the upper surface is getting colder or the thermal conductivity is increasing.
Meanwhile we are being told that we are all going to drown..
http://www.theaustralian.com.au/news/breaking-news/polar-ice-melt-accelerating-rapidly-study/story-fn3dxity-1226018474641
Here is some additional information about the phenomenon.
http://www.sciencedaily.com/releases/2011/03/110303141551.htm
It is somewhat misleading as it doesn’t mention a time period for the refreezing, much of which likely occurred during the last glacial period.
It says nothing about the current ice balance.
Keep in mind, for these very thick ice sheets… it likely takes centuries for an temperature change to travel from top to bottom. I’d love to see an actual direct measured temperature profile, top to bottom of the Vostok ice core, or other ice cores, but haven’t been able to find one.
It will be interesting to see if they determine whether the lakes were existing at the time of initial glaciation of Antarctica, frozen with a layer of ice, then slowly thickened over time, or whether they were from glacier melt as likely regularly occurs during interglacial periods with less cooling from the top to maintain the integrity of the glaciers, and to counteract the thermal radiation of earth’s core heat.
Perhaps if they get ice cores, salinity and trapped organisms will give some clues as to the origins of the lake ice, and hopefully something will indicate a time profile.
“mike g. says:
Leave it the French to design a passenger airplane that crashes if the pitot tubes freeze up.”
You don’t know what you are talking about. Any aircraft will. Want some amurrican examples?
The question about where the water is coming from is interesting. It’s certainly not from the ocean. This is very far from the sea and well above sea level. Neither can it be meltwater from the top of the ice – inland Antarctica is never above freezing. It´can hardly be meltwater from the Transantarctic mountains either, there is very little melting there. However large parts of the Antarctic icecap is warm-based, i e the temperature at the base of the ice is above freezing. Other areas are cold-based, i e frozen to bedrock. Presumably there is a hydrologic system beneath the ice where water melts, flows and refreezes, and probably this changes over time as the thickness of the ice and perhaps also the geothermic flow changes. There are cases in Antarctica where entire volcanoes grew in a waterfilled cavity in the ice (Gaussberg for example).
What this illustrates is that there is a lot we don’t know about what happens beneath a permanent icecap like Antarctica. Most of Glaciology is based on studies of small northern hemisphere glaciers and the the landforms left by the intermittent Eurasian and Laurentide ice-sheets.
Incidentally I don’t think this will be much of a problem for ice-core studies. Such re-frozen ice would be easy to separate from “virgin” ice by several criteria. However it does decrease the chances of finding really old ice in Antarctica.
This doesn’t invoke a warm fuzzy feeling about the stability of CO2 within this ever-morphing ice.
“Rising sea levels present one of the biggest threats to civilisation as we know it,” says Tim”
I know that “climate scientists” often seem to have more in common with creation scientists than they do with practicioners of hard science, but are they aware that there are sea level rise data sets covering many decades? Have they ever looked at them? Wikipedia will do fine for this one. http://en.wikipedia.org/wiki/Current_sea_level_rise. Does that graph look like it is tracking either the CO2 concentration or the IPCC et al notion of temperature?
I would agree that dramatically rising sea levels would be more of a threat to civilization than dubious science, but fortunately, it looks like we only have to deal one of the two and the threat doesn’t look to be sea level rise.
It is somewhat misleading as it doesn’t mention a time period for the refreezing, much of which likely occurred during the last glacial period.
George E. Smith says:
March 8, 2011 at 5:10 pm
“So Ok I’ll be the guinea pig. Now all this ice that is growing underneath the Antarctic ice; this is ordinary regulation H2O type ice is it not. Normal ice is made from normal H2O water which is a liquid substance, but it can also be made from gaseous H2O which is a gaseous substance; but in any case to make ice you generally need some source of H2O molecules: oodles of them; megatons of them in fact to grow much thickness of underbelly ice on Antarctica..
So ‘splain me the origins of this H2O, underneath the ice, could it be leaking out of the oceans, and up rivers somehow underneath the ice by some sort of caterpillary action ? Izzat possible ?”
_____________________________-
It is my understanding that if we were to remove the ice cap, Antarctica would be an archipelago not a continent.
What this is describing is basically an ice volcano slowly erupting ice from the center of Antarctica. The northern ice cap also freezes/adds ice from below does it not?
The more I learn, the more I learn how little I know.
George E. Smith says:
March 8, 2011 at 5:10 pm
George, Have you never seen a large spring issuing from the ground? Examples abound where rivers pour forth from underground aquifers in mind boggling volumes. Examples: Thunder River where Tapeats creek in the Grand Canyon pours out of a cave. Thousand Springs where millions of gallons pour from the Snake River Aquifer. Nature is astounding.
This is the way of learning new things: At first (IMHO the first century or five) simplistic ideas pop into mind, and we think we have a basic understanding of a phenomenon, and later on we learn of complications that tell us we have to add complexity to our understanding.
It isn’t that we are stupid, but it IS because we think that the model we have conjured up in our heads matches the reality. And once the brain model takes form, it is that which we are seeing when we see the phenomenon’s evidence being unveiled over time – we color our perceptions by the expectations that we have about our brain model, that it will prove out to be correct. So we keep crowbar-ing the evidence to fit the model.
Some of us will see the Emperor’s New Clothes and push for modification of the model/paradigm/construct, against some level of resistance by the rest. Progress does get made, but those brain models keep fighting for their very lives.
ALL brain models are wrong, in that they oversimplify. The real reality is much more complex than we will admit. So far, every step forward in information manipulation (i.e., computer CPU speeds and capacities) we believe that now we can get the complexity figured out. But IMHO we are centuries away from having the CPU/brain power to handle the complexities. Of course, the programmers and the scientists don’t want anyone else to know any of this; they make a living off people who think the programmers and thinkers are equal to the task. But good programming and good thinking need enough evidence and very solid methods in order to know the right approach. We are making a good effort, but we simply are too early in the game to do more than find new questions to ask.
And that is a GOOD thing, to get to asking those new questions. But we are only a very short way along the continuum. No, the programmers and the scientists don’t want people to know that we are a long way from really knowing what is going on. Our human hubris screams, like a 2-year-old, “I can do it myself!”
But in reality, we are only stroking ourselves and our vanity. Science is best approached with humility. Someone please tell Michael Mann that.
The AGWers are doing their bests, but their brain model is wrong. The skeptics’ brain model is wrong, too – but at least we admit it. And we can see to a good degree how wrong theirs is, too.
This study flat out craps on the simplistic idea that they understand what the ice cores mean. Everyone – inside their circles and outside – knows that the “understanding” of ice cores is based on an assumption. Now we find out about ONE of the complexities that muddies the water. Others will come…
Ah good, another unknown unknown has been identified and become a known unknown about how much this process effects icecap mass, growth and decline.
Lets throw away the now useless models and do some research so we know more…
There are many comments wondering where the water is coming from. It is simply coming from the ice sheet. What is being discussed is ice at the bottom of the ice sheet that becomes liquid (due to pressure or geothermal heat) and then refreezes.
Leo Geiger said on March 10, 2011 at 7:08 am:
1. Ice at bottom of sheet melts into liquid water.
2. This liquid water at bottom of sheet then refreezes into ice.
3. This makes bottom of sheet grow thicker, without any new water added?
Some clarification of your comment seems warranted.
General musing:
1. At the bottom of the ice sheet, there is liquid water.
2. There is great pressure, as one finds deep in the ocean.
3. There is a source of energy and nutrients, namely volcanic-type activity, as can be found deep in the ocean at hydrothermal vents.
Question: Is there life at the bottom of the ice sheet, similar to life found deep in the ocean at hydrothermal vents?
Leo,
Are you really ready to presume that groundwater movement that is present in all other geologic provinces is simply not possible or present in Antarctica? Me thinks thou doth presume to much.
Ground water venting at 56 degrees F. in Antarctica, considering the temperature regimes there, is still geothermally heated.