Erm, it is highly unlikely that the Earth will be covered in water from the melting of ice sheets - think someone's done the maths and assumed that if all the ice sheets in Greenland and Antartica melted, the sea level will rise by about 65-80 metres. Sure that's enough to cover a heck lotta land, but there still will be plenty left.

As for flying cities, well it's highly unlikely because we'd need some source of energy to keep it 'flying', unless we get to find some really low-density, but of high structural integrity to build such a city with, which looks highly unlikely really. Ditto with underwater cities, with the problem being keeping the water out.

So the premise of the post isn't true a priori. As to how likely such a city will be built, or whether there'll exist a need for such a city to be built in say the next 100 years, considering the challenges we have now? Extremely unlikely

Er, no, the problem is you have associated these things to 'natural things'. Your definition of 'fresh air', 'natural' might change if you were born under the sea and lived there for all your life, which is something you did not account for.

This post has been edited by bgeh: Nov 15 2009, 08:50 PM