>>9
Do you realize what you said made no sense?
Ice on land is definably not in the ocean and is above sea level. Melting it will increase ocean mass, which averaged across the world will mean a rise in ocean level. You might think a 10FT rise in ocean level is not much, but with shore slopes averaging 1 foot per mile, that's 10 miles inland that the new shore will be. Most of the area of most coastal cities will be underwater; those that raise dikes to stop the flood will be a tiny minority since such systems are very expensive (i.e. we cannot accommodate more than 1-2 more New Orleans in the USA before going bankrupt).
Although it's true that the Antarctic is depressed slightly from the weight of all those miles of thickness of ice on top of it, those miles still become vast volumes of water in the ocean with will inundate the coastal areas of the rest of the world (which will NOT rebound like Antarctica will).
And finally, there's simply no way Carl Sagan said that melting the polar caps would result in lowering ocean level. True, the north polar cap is essentially all on water, so melting it won't change ocean level. However, Antarctica's ice can raise ocean levels a LOT, for the reasons I stated above. According to the wiki:
http://en.wikipedia.org/wiki/Sea_level_rise
... Antarctica contains enough ice that when melted it will raise ocean levels by 61m (203ft). Since inland slopes can get more abrupt than shore slopes, say, perhaps 3ft/mile, then we can see that an Antarctic melt can send the ocean inland about 60 miles ... WORLDWIDE! All coastal cities will disappear, since no system of dikes can hold back 200ft of water around a city-sized region. All of Florida would be gone -- as part of the underwater continental shelf. The East Coast would retreat most of the way to the Alleghenies. Etc.