Ok, I'm sick of hearing this constantly spouted, so let's try clearing this up today.
There is no population problem. Not a real one at least.
Thomas Malthus' Population Theory was based on the false assumption that an increase in personal wealth would increase the child rate, increase the population and obliterate our food supply. Theoretical, this appears to make sense, because a higher standard of living would provide you with more money to raise more children. Yet, pragmatically, this has has proven to be utterly false. As personal wealth increases, the child rate goes down.
Yet, many continue to fear this and cite this, despite the overwhelming evidence to the problem's nonexistence.
There are indeed negative consequences of tight urban living, specifically in terms of pollution. But, there is no population problem. Human ingenuity is the solution. For that, we need more humans.