She Who Bicycles With Fishes

"David L. Johnson" wrote in message
...
On Sat, 22 Nov 2003 17:43:01 +0000, cheg wrote:

That's wrong. For one thing the Ross Ice shelf is less than 5% of
the
surface area of Antarctica. The average thickness of the
remaining 12.5
million sq.km. is over 2000 meters, for a volume of 25 million
cubic km.
The surface area of the oceans is about 300 million sq.km, so the
total
rise from melting all the ice in Antarctica would be about 80
meters.

Still questioning. It would seem that the average thickness of the
ice is
more than the average altitude of the continent. Again I don't
have good
enough data on this, but this site
http://astro.uchicago.edu/cara/outreach/coldfacts.htm claims that
the ice
gets as thick as 4776 meters, much more than the peak altitude of
the
continent. So a fair fraction of this ice is already below sea
level.

--

The peak altitude is actually about 4900 meters, and the average
elevation of the continent as a whole is 2300 meters. The land mass
would eventually come up a long way due to isostaic rebound once the
2.5E16 tons of ice came off, occupying whatever volume is now
occupied by submerged ice.

Unless an asteroid strikes the south pole, we won't know how much the
sealevel could rise for many human lifetimes at least. Might as well
go for a bike ride in the meantime.

In article ,
says...
On Sat, 22 Nov 2003 04:46:10 +0000, cheg wrote:

Theoretically, the water could rise 80 meters from where it is today. That
would turn my city, Seattle, into an island group.

I guess we'll find out. Did this theory predict when we would get this 80
meters? Not to mention where from. BTW, if it would turn Seattle into an
island group, most of the world's population would not have a whole lot of
sympathy, since many of the world's major cities are at lower elevations
than that. Hmm. Including Philadelphia. Yes, you, that is a major city,
or at least we like to think so.

I do believe that global warming is a real thing. I think that the oceans
rising 80 meters is way out of range. Consider this: How much would the
oceans rise if all the ice in the Arctic were to melt? The answer is 0,
since that mass is already supported by the water underneath.

Not quite: there is a lot of water stored in land-based glaciers in the
arctic zone as well. Most of it is in Greenland, but there are
significant amounts in Scandanavia, the Canadian islands and Alaska as
well.


The only
"extra" water that could raise the ocean levels is land-based ice, chiefly
in Antarctica, and even much of the Antarctic ice is floating.

As a percentage, very little of it is floating; only the ice shelves.
Almost all of it is sitting on the ground, even though the ground is
below sea level.

--
Dave Kerber
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In article 7PEvb.207752$ao4.741429@attbi_s51,
says...

....

BTW: the sea level was 120 meters lower than now 21000 years ago.
Could go either way...

That was during the last ice age. If the ice caps melt, it's certainly
not going to go that way.

--
Dave Kerber
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In article ,
says...
On Sat, 22 Nov 2003 17:43:01 +0000, cheg wrote:

That's wrong. For one thing the Ross Ice shelf is less than 5% of the
surface area of Antarctica. The average thickness of the remaining 12.5
million sq.km. is over 2000 meters, for a volume of 25 million cubic km.
The surface area of the oceans is about 300 million sq.km, so the total
rise from melting all the ice in Antarctica would be about 80 meters.

Still questioning. It would seem that the average thickness of the ice is
more than the average altitude of the continent. Again I don't have good
enough data on this, but this site
http://astro.uchicago.edu/cara/outreach/coldfacts.htm claims that the ice
gets as thick as 4776 meters, much more than the peak altitude of the
continent. So a fair fraction of this ice is already below sea level.

It is, but it's not floating, and if it melts, the land altitude will
rebound rather quickly once the extra weight is off it.

--
Dave Kerber
Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

"David Kerber" wrote in message

It is, but it's not floating, and if it melts, the land altitude will
rebound rather quickly once the extra weight is off it.

(Wandering further off topic)
How quick is quick? I heard from a not necessarily reliable source that
Scotland is still rebounding from the last ice age, which is a while ago.

If it rebounds at speeds resembling geologic time, wouldn't the rebounding
be substantially slowed because it would still have a lot of water on top of
it (i.e. until it rebounds up to sea level, it will still have ice or water
on it).

Not that I hope to be around to see it, but the thawing out of a continent
would seem to pose lots of interesting scientific questions.

"David Kerber" wrote in message
...
In article 7PEvb.207752$ao4.741429@attbi_s51,
says...

...

BTW: the sea level was 120 meters lower than now 21000 years ago.
Could go either way...

That was during the last ice age. If the ice caps melt, it's
certainly
not going to go that way.

--
Dave Kerber
Fight spam: remove the ns_ from the return address before
replying!

REAL programmers write self-modifying code.


IF the caps melt. Based on the geologic record, we're overdue for
another ice age. We haven't been around long enough to know what the
natural variability of climate is. It might overwhelm our
contribution. (Please, no global warming flame wars...)

"cheg" wrote in message
news:FeNvb.209567$ao4.745058@attbi_s51...

That's wrong. For one thing the Ross Ice shelf is less than 5% of the
surface area of Antarctica. The average thickness of the remaining
12.5 million sq.km. is over 2000 meters, for a volume of 25 million
cubic km. The surface area of the oceans is about 300 million sq.km,
so the total rise from melting all the ice in Antarctica would be
about 80 meters.

Don't forget to calculate for the difference in volume between ice and
water. Ice is about 90% as dense as water, so adjust your calculations
downward accordingly....

-Buck

"Buck" s c h w i n n _ f o r _ s a l e @ h o t m a i l . c o m
wrote in message ...
"cheg" wrote in message
news:FeNvb.209567$ao4.745058@attbi_s51...

That's wrong. For one thing the Ross Ice shelf is less than 5% of
the
surface area of Antarctica. The average thickness of the
remaining
12.5 million sq.km. is over 2000 meters, for a volume of 25
million
cubic km. The surface area of the oceans is about 300 million
sq.km,
so the total rise from melting all the ice in Antarctica would be
about 80 meters.

Don't forget to calculate for the difference in volume between ice
and
water. Ice is about 90% as dense as water, so adjust your
calculations
downward accordingly....

-Buck




OK, but partially offset by isostatic rebound, and other icecaps.If
this is calc is within 10% it's purely coincidental. I was just
showing that 80 meters is not an unreasonable number.

In article m,
says...
"David Kerber" wrote in message

It is, but it's not floating, and if it melts, the land altitude will
rebound rather quickly once the extra weight is off it.

(Wandering further off topic)
How quick is quick? I heard from a not necessarily reliable source that
Scotland is still rebounding from the last ice age, which is a while ago.

So is a lot of northern Europe. It's a measurable amount even on a
yearly basis, a few mm per year, and multiple meters in recorded history
(since routine record-keeping began in Europe).


If it rebounds at speeds resembling geologic time, wouldn't the rebounding
be substantially slowed because it would still have a lot of water on top of
it (i.e. until it rebounds up to sea level, it will still have ice or water
on it).

True, but that's a lot lighter than 2000 meters of ice *above* sea
level.


Not that I hope to be around to see it, but the thawing out of a continent
would seem to pose lots of interesting scientific questions.

It certainly does!

--
Dave Kerber
Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.