Global Warming

> > As for what I was thinking of, it's been theorized that melting in
> > Antarctica might result in the sudden collapse of the Ross Ice
> Shelf, which
> > might raise ocean levels much more precipitously than what we'll
> otherwise
> > get by gradual melting.
>
> The Total volume of the Ross Ice Shelf will increase the sea level
> negliably, less than 1 mm by my calculations. The sudden collapse will
> create a tidal wave in the pacific, but that is a one time event.
> Tidal waves happen for other reasons without massive policy changes
> and it can be argued successfully this one would never happen again.
>
> The problem that most people attribute to global warming crisis is
> that there is no catestraphic events to point to and say if we don't
> mend our ways this will happen again. I agree, that's a problem with the situation. An ice shelf (which is already floating on the sea) will make no
difference to sea level if it floats away and melts or stays where it
is. If we were talking about an iceberg, this would be true, due to the well known truism that most of an iceberg is below the surface. But here we are talking about ice shelveswhich are sitting above sea level, but might collapse downward into the sea if warming trends continue. This would actually add volume to the world's oceans not originally there. Shouldn't create any tidal waves either. However, Antartica does
have enough ice in its land glaciers to raise global sea levels by at
least 10's of meters. There may be signs now that some of them are
deteriorating faster than expected - if one of the great Antarctic ice
sheets were to be somehow rapidly destroyed, that would be pretty
dramatic. I went back and checked my source (Mark Prado's PERMANENT reference). I was in error in attributing the entire effect to the Ross Ice Shelf by itself. There is a much larger shelf known as the West Antarctic Ice Sheet or WAIS which is what Mark was talking about. He was citing DOE studies which suggested that the WAIS had melted before around 120,000 years ago, raising ocean levels by 7 meters. It was estimated that if this happened again, world ocean levels might rise by 5-6 meters. Mark was discussing this in the context of the possible economic consequences of NOT implementing SPS.
Regards,