10 races we should sterilize, number 6 will shock you, click here to learn more
I don't think that overpopulation is a problem today. Population collapse due to concentration of capital and power is.
Our carbon footprint would be an eight fraction of what it is if there was only 1 billion people in the world, current state of climate change would still be decades away giving us a bit more time to gradually change course, and consentration of wealth and power would be less dramatic as the workforce will be more limited (supply and demand for money itself).