That's an interesting question.

Greater Tokyo is home to about 37 million people. California's population is about 39 million people and Canada's population is about 35 million people.

This suggests that the Earth could easily sustain 7 billion human beings, and then some. There is certainly enough land available. But consider some the problems we are facing today - including but not limited to - unequal distribution of resources (and a finite supply of these resources), people starving to death (at a rate of 21,000 people each day according to a poster in this thread) despite producing enough food to feed everyone on the planet and many (most?) people on Earth still living in abject poverty.

Theoretically, after radically reorganizing the economy and radically reducing consumption in the wealthy nations, housing, feeding and clothing 7 billion people is certainly possible, if not very probable. But Earth's 7 billion people living a consumer capitalist lifestyle is, unless I am missing something, simply not physically possible. It's often said that for everyone on Earth to live like Americans and Western Europeans we would need an additional three planet Earth's worth of resources. I have no idea how accurate this is but as a species we cling to our consumer lifestyles knowing that it's responsible for many deaths and much misery in many parts of the world. If the consequences of global warming are as dire as many scientists claim, we'd rather jeopardize our species' very existence on this planet before seriously reducing our consumption levels.

Where was I going with this again? Overpopulation, right. It seems to me humans will choose instant gratification no matter what the consequences are. If it's not happening to me, right now, it's not happening. Nobody starving around here. The weather's nice too and the stores are well stocked. Oh, and the Internet, I have that too. In other words we are behaving like junkies. Yeah I could try quitting and living a productive lifestyle but you know I have enough dope stashed away and money to buy more when that runs out..and getting dope sick really, really sucks. I'm not a masochist dude and frankly I can afford to get high and not think about tomorrow or next week or whatever. I'll deal with that shit when and if I have to.

What blows me away is that China's small but growing middle class already includes more people than the entire population of the United States. I wonder where China sees itself in 15, 20, 30, 100 years? Unlike Western cultures, Chinese culture takes a long view and is much more prepared to sacrifice short-term gain or gratification for long-term gain. Or at least that was the common perception. From where I'm sitting it looks like humanity is on the brink of self-destruction unless something compels us to radically alter our preferred lifestyle or, even less likely, technology steps in to save the day. Really, I have no idea how things will actually play out. But humans suddenly embracing selfless altruism and self-sacrifice...nah, I just can't see it happening.

Well, that was 10 minutes of my life I'll never get back. Gave me a lot to think about though. Why am I talking to myself again? -