Population Control
At the current population growth rates, by the year 2500 people will be standing shoulder to shoulder on every piece of habitable land on this planet. So while our immediate problems have to do with global warming and obvious aggressions in various parts of the world, at some point population is going to become a focus as well.
It seems somewhat obvious to me that at some point there needs to be a type of population control on this planet. I've been racking my brain trying to figure out how to implement something like that that doesn't have any massive moral implications, and truthfully, I haven't ...