There’s some surprising reaction to the press release we covered on WUWT recently.
Here’s some excerpts:
Knowing how the massive ice sheets atop Antarctica and Greenland work is key to
predicting how global warming could raise sea levels and flood coastal cities. But a new study upends what scientists thought they knew. It turns out it’s not just ancient snow that makes up the ice sheets, but water deep under the sheets also thaws and refreezes over time.
To put it in non-scientific terms, lead scientist Robin Bell told msnbc.com, the study
redefines “how squishy” the base of ice sheets can be. “This matters to how fast ice will flow and how fast ice sheets will change.”
“It also means that ice sheet models are not correct,” she said, comparing it to “trying to
figure out how a car will drive but forgetting to add the tires. The performance will be very
different if you are driving on the rims.”
Reporting in this week’s issue of the peer-reviewed journal Science, Bell and his team
described how ice-penetrating radar peeled back two miles of ice a million years old in the
center of Antarctica.
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Ann In L.A. says:
March 9, 2011 at 10:24 am
I don’t suppose anyone can explain to me how a mountain range can be *underground*?
It isn’t. It is under ice.
“Antarctic ice sheet built ‘bottom-up
‘By Jonathan Amos
Science correspondent, BBC News”
http://www.bbc.co.uk/news/science-environment-12619342
“Polar ice loss quickens, raising seas
By Richard Black
Environment correspondent, BBC News”
http://www.bbc.co.uk/news/science-environment-12687272
“Ice loss from Antarctica and Greenland has accelerated over the last 20 years, research shows, and will soon become the biggest driver of sea level rise.”
Sea level rise accelerating
http://sealevel.colorado.edu/current/sl_noib_global.jpg
“Bell said the study did not look at what kind of impact the refreezing would have. “We are not sure if it will make them go faster or slower,” she said of ice sheets flowing into the ocean and thus raising sea levels.”
http://www.msnbc.msn.com/id/41869926/ns/us_news-environment/
No one claims to have accurate models of ice sheet flow.
Not to worry normal service has been resumed over here (in the UK), we are all about to die again! Or at least get a tad wet near the coast, not that we’d think about maybe moving away from the rushing water as it speeds in at 3mm a year. Still, annoyingly enough, the nearest coast is still were I left it over forty years ago. In fact it’s a tad further away in truth, but don’t let that inconvienient truth spoil a good story.
http://www.bbc.co.uk/news/science-environment-12687272
Richard Black to the rescue….
And there was me thinking ice cover in both Arctic and Antarctic look like they are on, if not a recovering trend, then at least not a terminal one, ie the death spiral isn’t, wasn’t and won’t be!
Damnit you’d think it was getting warmer because we are at THE END OF AN ICE AGE and waiting for the next one to start. The clue there is, end of ice age….
But maybe folks, like Richard, need to get these things in before good old mother nature shows them up to be the doom mongering bloggers (he is no journalist he is too gullible in my humble opinion) that they really are.
Ah you can’t beat a good rant….
re post by: tty says: March 9, 2011 at 8:53 am
Excellent point.
Not knowing all the available technology myself, but it seems that there must be a way to image that exact same area for heat… if warm/hot relatively to other areas, that would sure answer the question, by addressing what seems to me to be a very plausible confounding factor to their hypothesis of how the formation was actually caused. Even if now cold, it still wouldn’t mean that volcanic activity wasn’t the culprit, unless they can show growth/changes continuing while there is no thermal activity.
Regardless, I’d think that they’d have to figure out some way to determine if the cause is pressure and supercooled water hydrolics, or if instead the cause was vulcanism or differences in geothermal emissions — or if it’s perhaps a mixture of both geothermal and ice/water mechanics.
according to one of the BBC articles about this:
I’m having problems wrapping my brain around this – so, in areas where water is forced to lower pressure spots, the water freezes onto the bottom of the ice pack. Ok, fine so far.
But how does it ‘grow’ the ice pack from the bottom up, winding up being in large areas, 1/3rd to 1/2 of the pack depth? I mean, it seems for that to occur, the newly formed ice would have to be able to literally push the ice pack upwards…. that, or merely manage to fill in spots where deformities left lower pressure…. otherwise, as the bottom formed ice got thicker, wouldn’t it be unable to push the pack above up, and so be forced into areas of higher pressure were it would just turn back into water again?
Thoughts?
Ok people, settle down. Seriously.
This has nothing to do with “global warming” in any direct way, this is all about the physics of ice and large glacial sheets.
Nor is this a surprise. I learned about this as if it were common knowledge going through school, since we lived near mountainous glacial areas where this was important. There was always believed to be super cooled liquid water under ice sheets of sufficient weight, it’s what allows them to flow in the first place. This is nothing new in principle, maybe they just discovered more about the extent of the dynamics? Or maybe we all just forgot and had to rediscover it? Or maybe the climate world forgets basic physics and had to discover what everyone already knew all on their own? I have no idea, this really should not be news.
And yes, it could be defined as “squishy”. Increase the pressure and the ice lattice structurally fails and returns to liquid, decreasing the volume. Release the pressure, and the water returns to ice again, increasing the volume. See, squishy.
Now, increase the pressure even more past the pressure induced liquid state, and you’ll get another type of amorphous, rather than structured, ice. Want to see what I mean? Look at this graph http://upload.wikimedia.org/wikipedia/commons/d/de/WaterPhaseDiagram.png . There are MANY forms of ice, other than the simple Ice I(h) type that we think about when looking at ice cubes. Water is complex, and any model that fails to take into account the multiple ice forms and the relationships of pressure and temperature, will fail to accurately define glacial dynamics.
In the end, what this means practically, is that there is a lot more water locked up in Antarctica and Greenland than what is simply in glacial ice form, and the phase dynamics in response to temperature will be a lot more complex than what happens when you put an ice cube in your drink.
The glacier appears to be moving left to right. My geologic training asks why that tallest mountain, whose jagged peak is about one-half kilometer wide, has not succumbed to more erosion. Several others are surprisingly sharp.
Earthquakes are relatively rare in the Antarctic and many are attributed to post-glacial rebound. http://www.volcanolive.com/antarctica3.html I find it unlikely that mountain building is keeping these peaks elevated. The Gamburtsev mountain range is thought to be at least 34 million years old, plenty of time to erode sharp corners if the ice is solid and contains rock debris. tty (March 9, 2011 at 8:53 am) suggests that the mountains are the result of volcanic action. The AGAP Project concluded recently that the mountains are a result of plate tectonics, not unlike the Alps. http://en.wikipedia.org/wiki/Gamburtsev_Mountain_Range
Like a lot of scientific data (datum if you prefer,) this one raise more questions than it answers.
Sun Spot says:
March 9, 2011 at 10:15 am
@D. King says: March 9, 2011 at 9:50 am
I concur, what does that do to ice-core proxies ???
One assumes the ice for “ice cores” is formed by compression of layers of snow and information is gained by analyses of the gases and other material (dust and soot, perhaps). It will be apparent when a part of an ice core has formed from liquid rather than crystalline H2O. So the answer to your question is ‘nothing’.
Ged is right, this is old stuff, common knowledge among glaciologists.
DCC
If the ice at the base is frozen fast onto the rocky slopes of the “under ice mountain” then the ice is part of the mountain. It does not erode the mountain because there is little relative motion between the rock and the ice. There are major differences between frozen bed and non-frozen bed conditions. This can be appreciated in connection with the Laurentide Ice Sheet which covered much of North America during the last ice age. In some areas under this ice sheet, soft sediments were undisturbed by the growth and subsequent destruction of the ice sheet. This ice sheet is thought to have been over 3 km thick in some areas. Further, the rarther delicate structure of sediments deposited in water flow paths (eskers) beneath kilometres of ice has been preserved. These flow paths can be observed on the land surface today because the sediments stand out as elevated ridges and mounds. Its kind of like the effect you get when you stamp an embossed seal in hot wax to close a document.
So do not be surprised that there can be significant topography under an ice sheet. The base is not always erosive.
Ann In L.A. says:
March 9, 2011 at 10:24 am
I don’t suppose anyone can explain to me how a mountain range can be *underground*?
I’m not sure what is being referred to here. A mountain under ice such as in Antarctica should be easily conceptualized. Snow in this sense is the same as a sediment, such as fine sand being deposited from a river or near-shore environment. As depth builds up and the material is compacted the material becomes more dense. Sand layers can become sandstone and under more dynamic action that can become a metamorphic rock, naming based on the nature of the sand (say, quartz sand versus feldspar or something else). In any case, the sediment (sand, silt, clay, peat) can cover an existing landform of different and older parentage. The search phrase ‘buried landform’ yields 287,000 using Google.
A slightly different formative process is also possible:
Here is a link about a mountain in the Cascades of Washington State. Mt. Stuart is of 93 million old material.
http://en.wikipedia.org/wiki/Stuart_Range
Mt. Stuart came up from underneath younger sedimentary rocks in the Swauk Formation and others. Washington’s landforms and geology are complex but if you do a little digging (pun alert) you can find the information. A key term is “exotic terranes” as in
http://www.emporia.edu/earthsci/student/pachuta1/page1.htm
John F. Hultquist says:
March 9, 2011 at 1:37 pm
“It will be apparent when a part of an ice core has formed from liquid rather than crystalline H2O. So the answer to your question is ‘nothing’.”
I would think the super compressed crystalline H2O (snow ice) above the liquid ice formation should be read differently given the small diameter of the cores. No?
Steve Keohane says:
March 9, 2011 at 4:41 am
“In the depths, water remains liquid even when it is below the normal freezing point, due to pressure exerted on it. But once moved up to an area of less pressure, such supercooled water can freeze almost instantly.”
Under two miles of ice, nothing is going to move quickly, and therefore “almost instantly” is a totally inappropriate descriptor.
Steve – I have witnessed supercooled water turning into frazil ice so fast that I thought I had blinked and missed it – one of the most dramatic sights I’ve ever seen. I don’t see any reason to doubt this could happen at great depth. The volume did not change visibly (in a large container).
Melting Ice Sheets Now Largest Contributor to Sea Level Rise
ScienceDaily (Mar. 8, 2011) — The Greenland and Antarctic ice sheets are losing mass at an accelerating pace, according to a new NASA-funded satellite study. The findings of the study — the longest to date of changes in polar ice sheet mass — suggest these ice sheets are overtaking ice loss from Earth’s mountain glaciers and ice caps to become the dominant contributor to global sea level rise, much sooner than model forecasts have predicted.
“What is surprising is this increased contribution by the ice sheets is already happening. If present trends continue, sea level is likely to be significantly higher than levels projected by the United Nations Intergovernmental Panel on Climate Change in 2007.”
http://www.sciencedaily.com/releases/2011/03/110308150228.htm
Ah. Excuse me. “Underground mountain range”? I’d sure like to see one of those. Underwater, sure. Under ice, ok with that also. But underground? Who writes this crap?
I believe AGW is real and serious. Yet the article below shows some glacier melting is not due to CO2. I will not ignore this evidence even thought a part of me wants to. It would also be wrong to hype this work to imply AGW is not important. And note, the article is about human impacts.
Science News
Soot hastens snowmelt on Tibetan Plateau
Study suggests black carbon pollution has greater effect than carbon dioxide on region’s ice
By Janet Raloff, Web edition : Tuesday, March 8th, 2011
In high-elevation snowy regions, the warming effects of greenhouse gases pale in comparison to those triggered by soot, new computer calculations show. The finding could help explain the accelerating pace of melting on the Tibetan Plateau, which holds the world’s largest reservoir of ice outside of the polar regions.
http://www.sciencenews.org/view/generic/id/70777/title/Soot_hastens_snowmelt_on_Tibetan_Plateau
@Robert L
Funny how 95% of the innovation comes from a country with backward units of measure.
Its good to see some actual physical evidence being used for once versus the usual model results being cited as evidence.
It is unexpected. Noone thought there would such large regions of frozen water at the bottom of the glaciers. But in hindsight, how could it be otherwise. This mountain range has been glaciated for … wait for it …
… 42 million years.
42 million years of snow accumulation had to go somewhere because the snow accumulation adds up to much, much more than the 4 km height of this dome.
On the other hand, it is not a really large cross-section. It is only 20 kms of a 2,500 km wide glacial region. They need to stitch together a number of these sequences to put together what should be thought of eventually as a 3D perspective of the Antarctic ice-sheet.
It does point to a different view of the dynamics at the bottom of ice-sheets that cannot continue to be ignored by global warming science any longer. As I said at the beginning, there is now actual physical evidence.
DCC says: March 9, 2011 at 1:04 pm
The glacier appears to be moving left to right. My geologic training asks why that tallest mountain, whose jagged peak is about one-half kilometer wide, has not succumbed to more erosion. Several others are surprisingly sharp.
Here’s a larger version of the image, where you can see the vertical scale is exaggerated by 10x, making the peaks appear pointier than they are. It also looks like the plastic flow starts well ahead of the mountains, so with any difference in flow rate, the ice in contact with the peaks may be moving very slowly if at all compared to the rest of the icecap, resulting in the apparent lack of erosion.
Forgot to stick in the image link. Duh.
http://www.newscientist.com/blogs/shortsharpscience/assets_c/2011/03/Radar-thumb-600×433-118281.jpg
Bill Illis says: March 9, 2011 at 5:39 pm
. . . This mountain range has been glaciated for … wait for it … 42 million years.
42 million years of snow accumulation had to go somewhere because the snow accumulation adds up to much, much more than the 4 km height of this dome.
42 million years ago, Antarctica may not have been as far south. Here’s a fun Gondwana animation to play with –
http://www.parks.tas.gov.au/index.aspx?base=2889
@Rob R & Mike McMillan. If the ice is “part of the mountain” or moving more slowly at the base, both seem to contradict the conclusions of the paper that the ice at the base is “squishy,” thaws and refreezes, and affects the rate at which the ice flows. That’s why I wondered how much rock debris was being carried along.
I’m also wondering what the white reflection is just under the rock surface. I am assuming this is a negative image. “No reflection” is black, so this is more reflective material (Basalt flows? Till? ) It would be nice to see a 3D section of that highest peak; it might contain a collapse crater. Better yet, how about a few nice rock cores?
The apparent lower-down stratigraphic levels parallel to the surface would be “multiples” if this were a seismic image. It’s likely the same with radar. I’m a bit surprised at how far the radar managed to penetrate.
Doesn’t all this rather support Jaworski’s(sp) contentions about movements of liquids in ice and possible effects on sustances soluble in water?
tty says:
March 9, 2011 at 8:53 am
I fully agree, my impression of the image was the cross section of a volcano or an open center uplift with heat and steam vented at some time and then refrozen, COOL! pg