It is impossible to talk about overpopulation without defining some context first.

- what lifestyle do you want for your population?

- what processes do you have in place to achieve this lifestyle?

It is often mentioned that the US lifestyle cannot be sustained for 7 billion people and that therefore Earth has an overpopulation problem. Of course, given how insanely wasteful the US lifestyle and its underlying processes are, this is ridiculous. The problem lies not with the number of people, but with waste, mismanagement, and general consumerist insanity.

Worth noting is that Japan has ten times the population density of the US (while having a mostly inhabitable country due to its mountainous geography) while sustaining higher levels of comforts for its citizens than the US. One glaring difference is that Japan recycles most of its trash. In the US, everything is disposable and essentially no recycling ever occurs. The same level of complete waste applies to water management, energy management, and so on.