The population of the developed world is not increasing, and in most developed countries it is decreasing.
Wrong. The population of the developed world IS increasing. It's all from immigration, but it's still increasing. The US population has increased every single year. Are you trying to claim that immigrants aren't people?
And the population is growing in the 3rd-world countries too; so much that the excess is moving to the developed nations. Overall, it's increasing everywhere.
Also, the US is by no means overpopulated. I just drove across the country, and most of it is empty.
Yeah, because a lot of it is used for agriculture. Where do you think the food's going to come from when you pave over all the fields and replace them with subdivisions full of McMansions? There's also a serious lack of water in the Western states. Population growth is constrained by freshwater supply. You can't build a bunch of subdivisions in southern Utah when there's zero water there. I guess you're one of those people who won't be happy until every natural place has been eliminated and all land is filled with development, right?