How do we ethically reduce the population to a sustainable level?

Educated women have fewer children and rear healthier and better educated children, therefore educating girls and women is key (not that men and boys should be neglected). We cannot have unlimited consumption in a world of limited resources. The US has 5% of the world's population and uses 30% of the world's resources and produces 30% of the world's waste. Five earths would be necessary for all of us to consume at this rate, yet it is only just that all humanity have their material needs met. Over-consumption must stop. Humanity must develop new systems based upon justice for all not justice for the few, or there is no hope.