Boy, I hate those meassges that are wider than the screen :)

Anyway... you simply cannot exclude ice locked up on land when considering this!

The air above all of this locked up ice is presently warming too, causing it to melt and to run off into, ultimately, the seas. So it too is a source of rising sea-levels.
This locked up ice's speed of movement (mostly toward the sea too) is also accelerated by the warmer temperatures, leading to more ice getting to the sea more rapidly than previously.

Now I don't know if "global warming" is man-caused (aided) or not, but I do know this - man has occupied lots of shore line habitats on both seas and rivers, that could be severely affected by all of this added water. Whether global warming is man-caused or part of a natural cycle of things doesn't really matter as regards Manhattan "sinking" (or London or Hong Kong or ???).

The real problem is to mitigate the effects of such water level rises regardless of cause. Just because you are convinced that global warming is NOT man-made does not mean that shoreline encampments are not in danger!

Canada's arctic regions have been changing significantly in very recent times. What was permafrost is now thawed in spots and it is moving inexorably northward. This is causing all kinds of changes and threatening the existence of many plant and animal species. Now I am confident that Mother Nature will deal with these things but it nevertheless again has impact on how man has been living there.

As regards your original question, I'd hazard a **guess** that an iceberg's ice above the water more than compensates for the 'shrinkage' of the ice turning to water.

cheers

>( Sorry - somehow this originally ended up in Crystal Reports)
>
>Here's one that should get you going, esp. the boffins.
>
>We hear a lot about global warming, the melting of polar ice caps and the resulting rise in sea level. What prompted me to write this is that there was another program on telly last night bleating on about this. London, for instance will be inundated and the British Isles will look a lot thinner and more "fijordy". There are those that aver that sea levels are already rising, as witnessed at some Pacific atolls, etc. I, personally, don't subscribe to that because, as is well known, the Earth can rise, fall and tilt, esp. at techtonic plate boundaries such as volcanic island chains. So we have no yard stick on which to neasure this, other than the land, which may be sinking.
>
>Global warming and rising sea levels are very fashionable band-wagons to be on at the moment. Those not willing to get on, or opposing the view, tend to lose out on funding. Those who stick their necks out and openly oppose the view could be committing career suicide. Remember the bleating about the coming of the next ice-age back in the 70's? OK I appreciate that an increase in sea temp., around the Berring Straights etc., can cause more icebergs to melt and the Gulf Stream could shut down, pushing northern Europe into a big freeze, but that wasn't what was referred to in the 70's. And the USA needn't worry about this so much.
>
>My question is an academic exercise, based on a hypothesis by one of those brave men willing to stick their necks out:
>
>Given that water expands when it freezes, and that the majority of an iceberg is below the surface, wouldn't it therefore follow that the melting of the iceberg would result in its constituent water taking up less volume? Therefore, wouldn't the sea levels actually fall?
>
>The factors to consider are:
>
>

>1. What proportion of an iceberg is below the surface? Figures differ on this but I seem to recall that it's generally 5/6ths?
>2. What is the ratio of the volumne of ice to that of very cold water?
>3. The portion of the berg above the water is not displacing any sea water so that needs to be takem into consideration too when IT melts.
>4. for the purposes of this exercise we need to discount the ice locked up ON LAND (such as in Greenland's glaciers), that might slip into the sea (how much of the polar ice-cap is effectively one big iceberg anyway)
>

>I suppose the exercise can be approached simply by considering, say, 1 cc of ice floating in 1 cubic litre of water? Are there any other factors not considered above?
>
>Go figure :-)
>
>Terry
>
>PS I wanted to put this in Chatter-chatter but I could only find Visual Foxpro-chatter