If all the people in the world were in one place, how much area would it take up.
We have 7 billion people in the world which is 7,000,000,000 people. If one person took up 1 square metre each, the entire world population would take up only 7,000 square kilometres.
That would be the about the size of Puerto Rico or Haiti.
Haiti - Just over 7,000 square kilometres
The world land area is about 149 million km2, so every person could have about 20,000 square metres each. Does not sound like overpopulation just yet.
Also with the rate of increase slowing the world population will peak sometime this century and then start reversing. So no real threat. Nothing really to worry about.
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Eyes on Browne 
You have missed the point. It is not about how many people can fit on the planet, It is how many people can the planet sustain. Veganism would solve the problem but the ending of animal agriculture is not going to happen tomorrow. There are too many people on the planet already.
Thanks for your comment Richard. But so far all predictions of catastrophe have not eventuated. According to Paul Ehrlich and his friends we all starved to death thirty odd years ago. So excuse me if I don’t accept your logic. There has not been any credible evidence on how many people the earth can actually sustain. My point was actually illustrating just how un-impressive the scare mongering is with regard to over population. In any case, as countries develop, their populations will stabilize, as happens all the time.
But then again.. You would have to subtract all the areas like the sahara desert, vulcans, mountains etc.. You would also need to consider how to supply everyone with electricity, water, food etc.. Then the 20.000 square meters would be significantly reduced.
Ha ha. Hey Cyper, I always subtract my “Vulcans” first!!!! Ps I love the desert.