What would happen if the polar ice caps melted? Would there be enough water in the oceans to cover all of the continents? If not, what are the implications regarding the biblical great flood? Was that even physically possible? Does the earth have a fixed unchanging supply of water that is merely continually recycled? Just some weird questions that came to me in a dream…
>What would happen if the polar ice caps melted?
Santa Claus would end up in a condo somewhere.
>Would there be enough water in the oceans to cover all of the >continents?
No. The water levels would rise. but not as much as you might imagine. 90% of the world’s ice is in Antarctica and if it all melted, the oceans would rise by about 200’. If Greenland melts, add another 20.
>If not, what are the implications regarding the biblical great >flood? Was that even physically possible?
Certainly not. The average ocean depth is just over two miles. The top of Mount Ararat is almost 17,000 feet. There is not now, nor was there ever enough water on earth to cover the entire planet to a depth of 17,000 feet.
>Does the earth have a fixed unchanging supply of water that is >merely continually recycled?
Yes and no. Some of our atmosphere is lost to space and once in a while an iceball hits us. But the amount of water depends on the amount of it’s constituent gases in the atmosphere. People are still deciding whether we will still have liquid water when the sun envelops us as it is burning out.
200 feet?
The oceans are roughly 73 million square kilometers.
Antarctica is roughly 13 million square kilometers (including ice shelves).
The ratio is 5.6+ to 1.
To raise the oceans 200 feet, the ice cap at Antarctica would need to be 1,120 feet deep and the oceans would need to not overflow their coasts when the water began to rise.
I know that the greatest depth of ice in Antarctica is around 15,500 feet, but there are also rocky plains with little or no snow/ice cover. Is the average (mean) ice depth actually greater than 1,120 feet?
(I have not been able to find the mean depth of Antarctic ice.)
The main risk of the melting of the ice caps is the sudden and dangerous waves of swimming polar bears attacking boats and hapless swimmers at beaches across the globe.
Wouldn’t the great white sharks that already patrol the worlds beaches provide sufficient defence against these herds of marauding bear ?
What are the odds of this happening in the near future?
Are we really in global warming?
Only those of us who do not have our heads stuck under nice cool rocks.
No one really knows whether, to what extent, or how fast the antarctic ice cap will melt. It’s been disappearing at a pretty good clip for the past few decades, but the system is complicated enough that it may be gone long before scientists can develop a decent predictive model.
Source: http://pubs.usgs.gov/factsheet/fs2-00/
Last time I checked, for all you non-metric Dopers, 80 meters is 262.4640 feet.
Ah. I see you’ve been to Polar Bear Provincial Park. 
IIRC water expands when its frozen right? So if the ice caps melt won’t they take up less space then they do now? Or does it have something to do with the ice floating on water?
I hate being a layman…
There is a difference, but it is small. Ice has a density of about 0.92 gm/cc and water 1 gm/cc. The density of water varies slightly with temperature but not much and is maximum (1 gm/cc) at 4[sup]o[/sup]C.
This means that any volume of ice when melted would produce 92% of that volume of water.
If the earth was a featureless flat sphere and all of the water on Earth was liquid, what would the mean* ocean depth be?
(*disregard tides altogether)
According to this Britannica India article: If the Earth was smooth, (and there was no ice): 2,686 meters.
http://www.britannicaindia.com/nicad.asp?channel=kaleidoscope&tsearch=1854
In the case of Arctic ice, yes, pretty much. But Antarctica is not just a big block of ice, it’s a continent. Antarctic ice is sitting on top of land, and if suddenly melted and poured into the ocean, would make a substantial difference.
Water shrinks when it melts, but then starts expanding again after it warms past 4 degrees or so. So as the planet heats up enough to melt the ice caps, it also warms the oceans up enough to expand them.
From what I understand, this is a big enough effect to account for a decent chunk of the expected sea level rise.
And yes, it is happening, despite what oil company executives (present and former) would have you believe.
Has Antartica always been covered in Ice?
What about the icecube melting in the glass experiment? How much of the Antarctic ice is supported by land rather than floating on water?
It depends on whether it is winter or summer. This site on [url=“http://www.st-agnes.org/~dcrank/student/megan~2.html”] the Antarctic ice cap [/url has the following: “Also vulnerable is the floating apron of sea ice that surrounds Antarctica. During the winter, this apron effectively doubles the contintent’s size, then in the summer it shrinks 80%. The ocean currents flowing underneath the ice apron are cooled by the ice and this redistrubuted cooled water flows into the oceans. If this ice apron disappears ocean water throughout the world will become warmer and this will effect global climate patterns. El Nino which is a warm current in the Pacific has caused devastation in many areas. If the apron disappears or shrinks in size the effects will be much worse.”
[quote]
- Originally posted by Quercus*
**Water shrinks when it melts, but then starts expanding again after it warms past 4 degrees or so. So as the planet heats up enough to melt the ice caps, it also warms the oceans up enough to expand them.
From what I understand, this is a big enough effect to account for a decent chunk of the expected sea level rise. **
[quote]
Water expands slightly, but only very slightly, when heated above 4[sup]o[/sup]C. Water is nearly incompressible at all temperatures at which it is liquid which indicates that the molecules are nearly as close together as they can get at all temperatures.
At 4[suo]o[/sup]C water has a density of 1 gm/cc. while at 25[sup]o[/sup]C it is 0.99705. (Physics, Hausman and Slack) So one gram of water at the higher temperature would occupy1.00296 cc.
I don’t think so. Due to continental drift (Plate Tectonics), it’s not always been in the polar climate and fossils of tropical ferns have in fact been found there.
Yes. The average depth is 7,000 ft. Rememeber also that because of the weight of the ice, much of the Antarctic continent has been depressed below current sea level.
It began icing up in the Miocene period, 25 million years ago.