East Antarctic Ice Sheet getting thicker from underneath

I know nothing of glacial mechanics, but I have to wonder if super-cooled water does not play a significant role in glacial flow, rather than melting.

Additional to my earlier comment: I meant to say ‘melting, as called for by the Antarctic-ice-sheet-is-gonna-collapse crowd.’

super-cooled water is believed to be what brought down Air France Flight 447 in 2009.
“Accident investigators believe that super-cooled water in the clouds – well below freezing, but too pure to turn into ice – could have disabled the pitot probes.”
Read more: http://www.dailymail.co.uk/news/article-1282367/Air-France-crash-The-truth-disaster-killed-228-people.html#ixzz1G0Twk1Q6

Someone should tell Tim Naish about this because he seems to be coming to very different and alarming conclusions:
–Victoria University Antarctic and climate change researcher Professor Tim Naish has been watching the weather this year and has found nothing to reassure him.
In Antarctica, where Tim’s research is focused, the trends are the same. Both the Greenland and West Antarctic ice sheets are beginning to melt and new research suggests the same is happening to the world’s biggest ice sheet in East Antarctica.
“Rising sea levels present one of the biggest threats to civilisation as we know it,” says Tim.
Tim is Director of Victoria University’s Antarctic Research Centre and one of the lead authors of the next international climate change assessment from the Intergovernmental Panel on Climate Change (IPCC) , due for release in 2014. –
http://wiredcampus.chronicle.com/campusViewpointArticle/Climate-change-The-clock-is/388/

For those of you who are questioning how water can exist below kilometers of ice, google “triple point of water”. Water flows and collects in the valleys and is not found in any significant quantities under ice cores taken over domes. But ice flows as well (much more slowly).

Normal glaciers melt at the contact surface with the valley floor because of geothermal heat. This is why glacier streams flow. This water also helps glacier movement. So I do not understand this as there will be a significant amount of geothermal heat there and the thick ice insulates this surface from the cold atmosphere above.

This seems to be largely a mass redistribution process. The supercooling process has been recognized in modern glaciers. It occurs when liquid water, pressurized by the weight of overlying ice reaches temperatures below freezing but does not freeze due to this pressure. Freezing may occur as the water moves to areas of lower pressure. The critical element for this to occur seems to be the bed slope vs. ice surface slope ratio. If the bed slope is 1.2-1.7 times the ice surface slope, then freeze-on of the supercooled water may take place. This is essentially the process described in the abstract. The freeze-on process occurs along overdeepenings (or in this case valley sides where the appropriate slope ratios are liekly met).
As some of you have suggested, and the abstract mentions, this will have implications for interpreting ice cores. However, there are likely very diagnostic ‘signatures’ of ice accreted by supercooling (physical characteristics and isotopic signatures) which should allow for its recognition in ice cores. The supercooling process also entrains sediments and freezes them in the ice layers (if sediments are present along the flow path prior to freezing), which maks these layers distinguishable form clean ice and layers of ice-rich sediment derived directly from erosion.
This is highly interesting and yet another glimpse into the ever evolving understanding of the subglacial hydrology of Antarctica.
BTW, regarding a previous comment, there is ice accreting at the base of Lake Vostok.

icicling ,
I agree. I have simplified the system for those who do not understand the basics. Still it is more complex than the simple model that increasing atmospheric levels of CO2 are increasing the rate of melting of Antarctic ice sheets.

Yet another real world phenomenon that the models fail to allow for.

I read “getting thicker from underneath”, leaned back to laugh and my chair creaked. Time to lay off the doughnuts :/

““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.

I guess everyone has seen the latest spew from the liars at nasa:
http://www.nasa.gov/topics/earth/features/earth20110308.html

@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.

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 ?

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.

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.

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 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…

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.

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?

I was simply pointing out that the existence of liquid water at the base of ice sheets does not require mysterious flows from oceans (see George E. Smith’s comment on March 8, 2011 at 5:10 pm) or even springs. It can be there simply because of dynamical processes involving pressure and geothermal heat acting at the base of the ice sheet. No doubt springs exist, but the source of water from those would ultimately be from ice sheet melt too.