The problem with overpopulation is not where to stack people, it 's how to feed them
People always look in the future trying to resolve the problems by "today means".
In 20-30 years agriculture will be much further than its now.
I dont talk about where to stack them - if China was able to feed their people for so many years without opening to the world (I know it was poorly done but their technology was behind a lot as well) then the world will be able to feed itself no matter what.
This reminds me to all the:
"Oil is ending!"
"Gold is ending!"
"Water is ending!"
"Land is ending"
Says who? Some joker looking for fame?
from 30-40 years back dating to hit economy by end of century.
Nothing happened as technology went ahead - this is what many people miss.
Imagine what would happen if India/China would get their hands on newest farming technology... They would Export more food than any country in the world rather than importing it.
There will be no end of the world. There will be no end of civilization. We came through so much - people wont simply let it go and vanish.
End of the world stories are brought to the light since thousands of years - and none of those idiots shouting about 2012 being last year of the world come out with 2 things:
1) if world is ending - gave up your mortgage, move to Maldives, pick some Island and buy it. Then wait for day of reckoning in heaven. If you cant do this - it means you are just trolling.
2) today world is one mass brain - thanks to the web - world can defend it itself from most nasty things as instead of 10 brains in room (like when 2nd WW happened) we have hundreds of millions brains working on solutions.