Land problem

I have looked through some sites and videos this evening and remembered students today talking about how buildings might be built floating on water or in the air in the future. And it reminded me of the other problem we have today- lack of land for the buildings. The population is becoming bigger every day and the number will keep increasing, but the land won't. Although, humans started expanding the land- building artificial islands.






That's some examples i have discovered about all of this thing:







I wonder how sustainable it is?


Btw, i would like to suggest you all to browse one interesting site called Architizer:
http://www.architizer.com/en_us/?country=en_us
Hope you will enjoy it :)