From: Kevin Bluck (kevin.bluck@mail.com)
Date: Fri Jul 26 2002 - 09:48:34 MDT
>Scientists seem to agree on at least one aspect of global warming: any sea
>level change will be gradual.
I can think of at least one scenario in which sea level change would be
abrupt and catastrophic. If a large portion of the Ross ice shelf should
detach and slide into the ocean, sea levels could rise almost overnight as
much as 2 meters. Once the shelf was gone, sloughing of the West Antarctic
ice sheet would likely accelerate greatly without Ross to help hold it
back, producing further sea rises measured in meters over a relatively
short timescale measured in decades or less. Happily, the much larger East
ice sheet seems to be much more firmly anchored, but Ross is a definite
"weakest link" for the West sheet.
Admittedly unlikely, but certainly not outside the realm of possibility.
Every extra degree of warming makes it more likely. Even if we think we're
monitoring the integrity of the shelf and its looking good, under-ice
volcanic activity at a decisive point against already-weakened ice could
produce a worldwide catastrophe with little notice.
Could arresting the progress of global warming now provide the necessary
"safety margin" to prevent such a catastrophe? That nobody knows for sure.
Perhaps a sudden collapse of Ross is already inevitable and we just don't
recognize the dynamics. Or, perhaps far more warming would be necessary
before it becomes any sort of possibility. Perhaps the shelf is sound now
but an unlucky wildcard such as volcanism could set it off. All this we
just don't know.
--- Kevin
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