> anyway, still, maybe not texas, but with a few other states besides, we'd be fine. an acre per person. no overcrowding.

The problem is that the population is growing exponentially, so the more people there are, the faster it grows. I'm not sure what the exponent is, but check out Brain Food math puzzle #6, which is a problem that describes an exponential rate of growth where the exponent is 2. It isn't until the end of the second week that you make anything that even resembles the pay of a normal job, and yet look what happens in the third and fourth weeks.

Suppose the population doubled every twenty years. If the whole of the United States were enough to sustain us all (and I can hardly believe that if China isn't even enough for just its own citizens), then in twenty years, we'd need most of North America. Another twenty years, we'd need all of it, and South America too. Another twenty years, we'd fill Africa and much of Europe. Another twenty years, and Europe and most of Asia is filled. Only a few years after that, and we're all done.

Obviously (hopefully?) the population doesn't increase with that rate of growth, but the rate of growth *does* increase with that kind of acceleration. It is said there are more people alive today than have EVER died. (The joking conclusion to this statement is that you have better than even odds that you'll never die. :-) ) I'm not trying to start a panic or anything -- I'm not worried about it myself -- but some years down the line, after we're gone, and barring apocalyptic events, it'll be a problem.