[davehc]

This is not strictly about global warming - I see that thread has been run into the ground. It is regarding the linked sea level rise.
Whe I was a schoolchild, one of the standard expoeriments was to lower a large piece of ice into a 2 ltr beaker and top it up with water. We had a home made drop scale floating on the surface. The object was to prove that water was more dense than ice.
When the ice melted, the surface of the water went, without doubt, down.
Bearing in mind that ice(bergs) are 90%under water, how does this correlate with the theory of the sea level water rise over the next hundred years?
Is it possible bacause the Antartic Ice, much of which is land based, would over compensate?

[katonca]

Interesting question.

Maybe all the doom and gloom shows which portray NYC being under water within the next____years should have studied 5th grade science first.

[ekim68]

Don't forget about the Greenland ice mass...

[LANMaster]

Exceptional question in post #1.

[SlackAli]

Do you think somebody here ought to take the lead and forward this question on to the UN for them to forward to all the climate institutes and university departments working on this problem around the world in case they haven't thought of it....?

[TRS-80 vet]

Originally Posted by davehc

This is not strictly about global warming - I see that thread has been run into the ground. It is regarding the linked sea level rise.
Whe I was a schoolchild, one of the standard expoeriments was to lower a large piece of ice into a 2 ltr beaker and top it up with water. We had a home made drop scale floating on the surface. The object was to prove that water was more dense than ice.
When the ice melted, the surface of the water went, without doubt, down.
Bearing in mind that ice(bergs) are 90%under water, how does this correlate with the theory of the sea level water rise over the next hundred years?
Is it possible bacause the Antartic Ice, much of which is land based, would over compensate?

Excellent!

[wacor]

Very interesting.

I am sure there is an explanation.

Maybe Stoner will have some thoughts. As I recall he took courses related to geology.

[wacor]

tried to search for some answers and I think it comes down to whether the ice is on water or land. looks like minimal impact for the north pole as that is predominantly ice on water but the south pole is another issue. only thing is that the doom and gloom forecast would require the south pole to have major temperature rises to have that scenerio come true.

what i did find interesting was the following. which came out of Wiki but I think this was peer reviewed. seems that while there are lots of theories we have some actual data from last century.

and that data seems to contradict some of what is being theorized it appears.

global warming and sea level rise

What about the effects of human-induced global warming on SL rise? Will it really increase the rate above its natural value, as predicted by the IPCC? We do have a handle on this question by observing what actually happened when the climate warmed sharply between 1900 and 1940, before cooling between 1940 and 1975. The answer is quite surprising and could not have been derived from theory or from mathematical models. The data show that SL rise slowed down when the climate warmed and accelerated when the climate cooled. Evidently, ocean-water thermal expansion and mountain-glacier melting were less important than ice accumulation on the Antarctic continent (which lowers SL).

[ChrisJones]

A very interesting queation Dave.

With regard to the ice on water, I think you are correct, at least in your hypothesis. It seems to make sense that sea levels will fall after the ice melts (I did just the same experiment when I was at school), however I have no idea how this would work on a global scale, though that's why I'm not a climatalogist or iceologist or whatever they're called!

Another thing to remember, as somebody has already mentioned, is the Greenland Ice sheet. From what I understand (I'm recalling this from when I was in school so don't shoot me if I'm wrong!) it is pretty massive and containes an enormous amount of water. It's nearly 1500 miles long and nearly 700 miles wide at it's widest point. It averages more than a mile in thickness and reaches two miles thick in some places. I recall being told it is the second largest body of fresh water in the world after the Antartic ice sheet. My brain is too fried from work to try and guesstimate out how much water it actually contains but I'm guessing it's quite a lot. Could this perhaps account for the predicted sea level rises? It's also worth noting that it wouldn't just be the Greenland ice sheet that would melt, Ice built up on Canada and Siberia's northern shores would also count for a lot of water.

Again, thanks for the interesting thread Dave, you've inspired me to go and use the internet for something that doesn't involve porn!

Chris.

[LANMaster]

Originally Posted by SlackAli

Do you think somebody here ought to take the lead and forward this question on to the UN for them to forward to all the climate institutes and university departments working on this problem around the world in case they haven't thought of it....?

YES! Great idea. Go for it!

Assuming that you think they will listen to the clear logic rather than simply blow you off as a "denier"

[ChrisJones]

Wikipedia confirms I was quite close with my dimensions and it being the second largest body of fresh water.

Wikipedia also says:

"If the entire 2.85 million km³ of ice were to melt, it would lead to a global sea level rise of 7.2 m (23.6 ft.)[2]. This would inundate most coastal cities in the world and remove several small island countries from the face of Earth, since island nations such as Tuvalu and Maldives have a maximum altitude below or just above this number."

I believe the page has been peer reviewed and there are no disclaimers or objections. LINK

This is also worth a look, it examines the Greenland and Antartica ice sheets. http://www.grida.no/climate/ipcc_tar/wg1/416.htm

[valis]

good question. One of those 'doi, why didn't I think of that' issues.

The other thing to consider is that the glacier run-off is straight freshwater dumping into, and thereby decreasing the salinity of, seawater. As salinity decreases the freezing temperature of the water goes up, albeit not by much. I've always liked that aspect of it; global warming will cause a big drop in temperatures as ice creeps down due to decreased salinity.

[valis]

The other thing that is being overlooked here is that these ice sheets are currently land-bound; they are NOT immersed in the water, so any addition to the oceans has no choice but to raise the water level. Take the same test tube, fill it to the brim first, THEN add the ice, see what happens.

[iltos]

well for starters, there has been a lot of study done on the density of ice compressed by mass above it....(i think it was SlackAli who hinted at the fact that climatologists have probably already thought of this density thing )

water's density is considered to be 1mg/m3
standard everyday ice has a a density of .917mg/m3
compressed ice in the antarctic ice shelf has a max. density of .921mg/m3...even in experiments that have been done with the salt content of sea ice, this density seems to be the maximum density of naturally occuring ice

kind of an interesting sidebar....in the lab, something call amorphorus ice has been created by supercooling water very quickly....too quickly for the developement of a crystalline structure.....densities in this ice reach up to .970 mg/m3 and the ice has some practical apps, which i read, but couldn't even understand

so i guess it boils down to the total volume of ice that is not already displacing water.

[iltos]

some of those "volume of water" facts and figures....
note that these number are for land based ice, as v. points out above...and that the figure ranges from 87% of the freshwater, down to 75% of it.....
that's all i'm sayin (well, almost )....i'm leery even posting this much, and having somebody come along and turn this into a thread about global warming......

http://www.exploratorium.edu/climate...ere/data1.html
Glaciers and ice sheets currently cover 10% of the land area on earth and contain about 75% of its freshwater.
{click on the question mark in center of the page, to hear an ice scientist type talk a bit about the state of change in antarctic glaciation}

http://www.waterencyclopedia.com/Ge-...te-Change.html
Today, permanent ice covers a little less than 10 percent of Earth's land surface, yet contains almost 87 percent of its fresh water. The majority of the ice, 29 × 106 cubic kilometers (approximately 7 million cubic miles), is in Antarctica. The Greenland Ice Sheet holds 2.95 × 106 cubic kilometers (706,000 cubic miles) of ice, whereas glaciers and ice caps amount to about 0.18 × 106 cubic kilometers (43,000 cubic miles). Although glaciers and ice caps make up less than 1 percent of Earth's terrestrial ice volume, their small size allows them to respond rapidly to climate change.
The best estimates indicate that while the Greenland and Antarctic ice sheets are near balance, glaciers and ice caps are shrinking worldwide, contributing as much as 0.25 millimeters (0.01 inch) per year to global sea-level rise.

http://walrus.wr.usgs.gov/infobank/p.../21.01.27.html
{this is the USGS site...i think it's for kids....that's why i could understand it....there is a ton of highly technical writing out there 'bout this....most you have to pay for....the rest i couldn't even begin to understand}
Sea level rose about 12 centimeters over the last century, again due to the warming of the inter-glacial climate and retreat of the glaciers worldwide.
But the current rate of rise is about three times as fast, and estimates of sea level rise over the next century vary from 30 centimeters to over 2 meters.
This may not sound very threatening, but 30 centimeters of sea level rise would correspond to 500 meters of coastal flooding in some areas of the world.