From: Mike Lorrey (mlorrey@datamann.com)
Date: Sun Jul 28 2002 - 18:57:43 MDT
ABlainey@aol.com wrote:
>
> In a message dated 29/07/02 00:17:03 GMT Daylight Time,
> mlorrey@datamann.com writes:
>
>
> >THis is absolute hogwash. The Ross Ice Shelf is buoyancy neutral,
> >meaning that it is already floating on the ocean. I wouldn't 'slide
> into
> >the ocean' since it is already there. It's melting would neither
> raise
> >nor lower the ocean levels one bit.
>
> It is my understanding that the main threat from rising sea
> levels is due to the expanding volume of the existing oceans because
> of the temperature rise. The melting of the ice sheets at any location
> in the globe will mean that the water created will have just about the
> same volume as the ice sheet itself. Bearing in mind that water
> expands when frozen and therefor has a smaller volume when defrosted,
> Also bearing in mind that 1/10 of icebergs/sheets etc are above the
> water. I will admit that the exact figures regarding this still eludes
> me, mainly because I haven't been arsed to work it out. I would expect
> that having done the math, the net yield of extra ocean volume will be
> negligible on a global scale.
More hogwash. Water, unlike other materials, doesn't have a linear
expansion curve. Water displaces the same amount of ocean frozen or
liquid, as any competent scientist can attest. Any amount of warming
will also produce a greater amount of evaporation, thereby leading to
more rain clouds, which reflect sunlight and thereby lead to cooling, in
addition to increased precipitation in the polar regions.
> As far as I can see, the melting of any ice sheet will only
> yield a short term impact in its locality, such as Flooding.
The Ross Ice Shelf is not an Ice Sheet, since it is floating. The West
Ice Sheet, despite part of it resting on bedrock at levels below sea
level, is protected by a thermocline 'ice line' that is far below the
level of the bedrock surface.
> I think the greater impact from this will not be in sea level
> changes, but from the change in salinity of the oceans themselves. We
> already know that salinity changes drive climatic controls such as the
> Gulfstream, which keeps Great Britain many degrees warmer than it
> should be, given its position. And as far as I am aware, El Ninyo is
> also driven be salinity changes in the pacific.
> I will stick my hand up and say that my views on this are mainly
> assumption based on a little fact. Am I way off?
> If I am way off and sea levels do rise. About a 3 meters will do me
> fine. My house would then become prime beach front property and I
> could hire out pedlo's for a living :o)
If Greenland's Ice Sheet collapses, which is far more likely than
anything in Antarctica, it will result in a sea level rise of between
3-9 feet, which ought to serve you fine. A good proportion of this
water, though, could easily be sequestered in the Caspian Sea basin.
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