World population growth will resolve itself. It's already happening.

Just look at Japan. Destroy middle class wealth and prosperity, socialize everything, make work meaningless, stressful and boring (zombie corps), and soon the young people stop having babies.

Create MCS (Main Character Syndrome^TM), aka create a self-absorbed, narcissistic youth preoccupied with navel gazing and selfies, and no long term career prospects, no money, nothing but debt, and they stop having babies.

Problem solved.