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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Mike McMillan says:
March 9, 2011 at 5:57 pm
Ah yes, much better image. Looks like it refroze a long time ago, About 1300 meters of snow deposits layered over the refrozen ice dome and no movement during that time. pg
“Rational Debate says:
March 9, 2011 at 12:28 pm
I wonder about this too. Is there a change in VOLUME from super cooled water to ice?
That might account for the increase in elevation.
“Mike says:
March 9, 2011 at 3:46 pm
Melting Ice Sheets Now Largest Contributor to Sea Level Rise”
I read the article plus a couple of others and conclude they are propaganda scare stories.
Do the math yourself. It is quite straight forward. To raise global sea levels by just 1 metre by
2100 a total mass of 400,000 CUBIC KILOMETRES of land borne ice must melt!
This will be very, very visible. You won’t need satellites to measure it. The media will be there
by the shipload.
Next, we will find out that they didn’t account for the compressibility of the moutains.
Bill Illis says: “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. ”
It went into the ocean. Ice flows are a continual cycle. Ice moves ice from the interior (where it forms from accumulated snow fall) to the oceans where it melts. The ice from the time the Antarctic ice sheet first formed has long since moved into the ocean and melted.
Further explanations and context for the research can be found on Columbia U’s web site:
http://www.earth.columbia.edu/articles/view/2783
@ur momisugly Richard111 says:
March 10, 2011 at 12:04 am
I did the math and got the same result as you. But there about 30 million cubic kilometres of ice in Antarctica. If 1.4% melts we have a 1 meter sea level rise, by your calculation.
http://hypertextbook.com/facts/2000/HannaBerenblit.shtml
The point however is not to watch this happen on TV, but to try to stop if from happening by changing how we use and generate energy if we can. Don’t dismiss the science just because you don’t like it.
The gist of their title & comments seems opposite to what I’m seeing in the radar-slice, as others have noted. The “squishy” ice I see is in fact the top layer, compressing and forced overtop a solid, immovable dome of refrozen water, which is anything BUT squishy. Whether that plume originated from volcanic activity is certainly interesting.
Maybe they’re noting the ability of the top-layer to slide roughly intact over such an impediment? I dunno.
beng: It’s all ice. There aren’t “solid” and “squishy” versions of ice. The point is that some has been melted, refrozen, and deformed. The melting and refreezing process is *like* some of the ice sheet being “squishy” because of this process.
People should be a little more cautious about drawing all kinds of odd conclusions based entirely on a subjective interpretation of a radar image, or taking literally the analogies and metaphors used by scientists when trying to describe a process.
You mean like “Hide the decline” and “Mike’s Nature trick?”
DCC
I am not entirely sure I understand your point. Flow in an ice sheet can be quite complex. Much of the movement is ductile creep which can be distributed through 1000’s of metres of ice thickness. There may also be surfaces that act as shear zones. These zones of concentrated deformation are not always at the base. They can be 100’s of metres to kilometres above the base.
At this stage it is too early to say what style of deformation (if any) is occuring at the base of the so-called squishy ice. In addition our normal concept of thawing and refreezing might not apply at the rock contact at the base of the ice sheet.
No where do I see any consideration for the possibility that an aquifer is venting ground water under the glacier, supplying water for new ice to the basement ice series above the bedrock. An ice volcano if you will. Springs great and small flow on all other continents, why not there? Glacier orogeny.
Here is another radar image of this mountain range under the ice (this time, not including a big re-feeze region). Most of the mountains in this range show a Matterhorn-like shape, the glaciers have turned them into sharp spikes.
http://www.ldeo.columbia.edu/res/pi/gambit/images/Beth&AD/Mountains_BW.jpg
Hmmm. Not likely to be rock. Might it be ice?
Don’t forget about the vertical exaggeration used on these radar images. They aren’t as spikey as a casual glance at the image would lead one to believe. The images are not a pure cross section either. There is superimposed off-axis information being projected onto a flat image.
And it is most definitely rock.