West Antarctica Total Disintegration - a worse case scenario?


by zankaon
Tags: antarctica, case, disintegration, scenario, west, worse
zankaon
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#1
Dec24-07, 02:14 AM
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Antarctica has a total of 25.4 million km^2 of ice. West Antactica Ice Sheet (WAIS) has a volume of 2.2 million km^3 of ice. WAIS is that part of Antactica west of transantarctic mountains. The surface of earth is 510,072,000 km^2; while the ocean is 71% of such surface; giving 361 million km^2. So 2.2 million km^3 of ice / 361 million km^2 of ocean surface = 6.1 x 10^-3 km of sea surface rise from WAIS total melt. This is a 6 meter (18 feet) sea surface rise. However one has the caveat, that WAIS is approximately 1000 ft below sea level. So for average ice thickness of 4000 ft, then 1/4 of WAIS melt would seem to stay, forming an archipelago. Therefore resulting in only about 13.5 feet rise in sea level. This then is supposedly one of the worse case scenarios for global warming.
See references:

earth.http://http://en.wikipedia.org/wiki/Earth
http://en.wikipedia.org/wiki/West_Antarctic_Ice_Sheet
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zankaon
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#2
Dec25-07, 03:06 AM
P: 166
But over what time span? 100yrs or less, vs 200-500 or 1000 yrs?
zankaon
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#3
Apr29-08, 12:46 AM
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Another approach to calculation of sea surface rise: West Antarctica ice sheet thickness is average of 2000 meters. http://www.sciencedaily.com/releases...1218073333.htm

W. Antarctica has a maximum bed depth of -2500 m (i.e. below sea level). So if average depth of bed of W. Antarctica is -1500 m, then approximately 500 m. elevation above sea level for ice sheet. So then just 500 m. of ice x surface area of W. Antarctica would be distributed over world oceans since W. Antarctica is an archipelago. W. Antarctica S.A. is approximately equal to that of Western Australia or 2.6 million km^2. So for total ocean S.A. of 361M km^2, such latter S.A. is equivalent to 139 W. Antarctica; that is, 361M/2.6M = 139. So 500 meters or 1500 ft distributed over 139 W. Australia would give 1500/139 = 10.79 ft sea surface rise world wide.

Andre
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Apr29-08, 05:53 AM
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West Antarctica Total Disintegration - a worse case scenario?


here is some likely cause of unstability of the West Antarctic Ice Sheet.

http://www.sciencedaily.com/releases...0120160720.htm

The subglacial volcano has a 'volcanic explosion index' of around 3-4. Heat from the volcano creates melt-water that lubricates the base of the ice sheet and increases the flow towards the sea. Pine Island Glacier on the West Antarctic Ice Sheet is showing rapid change and BAS scientists are part of an international research effort to understand this change.

Using airborne ice-sounding radar, scientists from British Antarctic Survey (BAS) discovered a layer of ash produced by a 'subglacial' volcano. It extends across an area larger than Wales.
Obviously, getting out of your SUV is not helping to stop these processes.
wolram
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#5
Apr29-08, 09:04 AM
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I do not want to hijack the thread but a related question,

Would significant water depth increase put enough extra pressure on the sea bed, so that earthquake and volcanic activity increases globally?
vanesch
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Apr29-08, 09:45 AM
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Quote Quote by wolram View Post
I do not want to hijack the thread but a related question,

Would significant water depth increase put enough extra pressure on the sea bed, so that earthquake and volcanic activity increases globally?
There is not going to be more MATTER on earth, so I don't see how we could get a serious increase of pressure on the sea bed.

If land ice melts, this becomes more *distributed* matter (what was all on one heap is now distributed all over the oceans), and when the water *expands* (because of higher temp) this is not going to change its total weight (and hence pressure).
Count Iblis
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#7
May13-08, 01:40 PM
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I did read about a possible link to volcanism.

see here
vanesch
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May14-08, 01:20 AM
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Quote Quote by Count Iblis View Post
I did read about a possible link to volcanism.

see here
First of all, that link is full of fearmongering material (especially now that it seems that the antarctic ice sheet is actually growing).

But the point was *global* increase in pressure, which is impossible of course. What can happen is that the redistribution of matter shifts certain equilibria, and gives rise to more, or to less, tectonic activity.
LURCH
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#9
May14-08, 09:37 AM
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Almost certainly more, I should think. The Antarctic continent would have less pressure on it, and the sea floor would have more. The crust would need to shift to adjust to the new distribution.

But has anyone seen a map of what this scenario would mean for coastal regions?


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