Originally posted by 2bighorn
Correct. The amount of melted Antarctic ice is good for a sea level rise of about 0.02 inches per year. It would take some 3 to 4 hundred years to melt completely if rate of melting remains at current level.
And if is limited to melt water only, and no
further break-ups of the ice shelfs in West Antarctica occur in the future .... not that anyone saw the
last couple break-ups coming before they happened so spectacularly..... then I'd concede the point that the ocean rise will happen slowly.
Nothing to say that those ice shelves won't break off in the future.... and the glaciers behind them now also have access to the sea --- previously they have been essentially held back. Domino effects. Almost everything in the overall climate model has a positive feedback/reinforcement loop associated with it, once you get past a certain point..... a tipping point..... where the original effects are no longer absorbed or dampened.
Large break ups of the ice shelf, melting of the pack ice, and large scale melting in Greenland are of concern. Sudden climate shifts also are a possibility; they've happened in the past, and we could be headed for another in the near future.
The one I personally worry about having the biggest effect in the shortest time period is the methane sequestered in Siberian permafrost, and the deep sea beds..... if the permafrost melts (open water over the Arctic Sea for longer periods each year, absorbing more solar radiation, thus heating up the northern latitudes, and melting the permafrost), or the seas warm enough to free up seabed methane, then all bets are off. There is so much methane there that can be released in a short span of time that we could see serious increases of world-wide temperatures .... and it is the worse kind of positive feedback loop...... Earth's version of the runaway greenhouse effect.