The world is grossly overpopulated?

We can't. Nature will do that for us. You are going to see a huge rise in the number of fatal communicable diseases in the next century, as well as a rise in the number of large wars and famines that leave millions dead. These are the results of human overpopulation. It will be painful, but ultimately the problem will be taken for us, although in a manner that none of us would chose.