Populations become stable when life is good, when there is plenty of food, shelter, clean water. It's just basic biology, Kiera. Animals who's offspring have lower survival rates have more babies, those who have better survival odds put all their effort into fewer offspring. Humans are animals too, and these triggers are both subconscious and powerful. Bring people into a kinder world, a secure world, and nature will do the rest. Simple science shows that the way forward is compassion, in sharing the global food surplus, in realizing that we have the capabilities to produce far more food than we do with far less impact on nature. We can build tall, farm vertically... utopia is possible once we refuse the shackles of economics. Love wins, right?