I remember reading an article on the BBC a couple of years ago that predicted that the global population will peak at the end of this century and then go down.
I also remember from an Anthro class that the only factor in regulating population explosions is the level of education of women in a society. The more educated the women, the fewer children they have. Places like Germany and Italy are currently experiencing population decline, and it will only be a matter of time before the rest of the industrialized nations experience the same thing. A hundred years ago, it was necessary to have a lot of children, because you could count on a number of them dying, and you would need a lot of people to work on the farm. Now, there is absolutely no reason to have more than 2 children.
We could always go the Ishmael route and stop sending aid to countries and regions that can't support their populations themselves. I believe the line was, "Hungry people make more hungry people." And if we are producing enough food for 7 billion people, even if our global population is 6.5, the population will rise to meet food production. By the time we have 7 billion people, we will be producing enough food for 7.5, and so on. Not a terribly optimistic outlook (not to mention it makes me feel a little icky inside), but Daniel Quinn (the author of Ishmael) has a point.