Since we know the single best way of bringing down high birth rates is to empower women by giving them access to reproductive health choices (including contraception and abortion), education, economic opportunities, and legal protection of their rights, empowering women ought to be one of our highest priorities. (As Kim Stanley Robinson puts it, empowering women is the best climate change technology.)
In 2005’s “Beyond Oil – The View from Hubbert’s Peak”, Kenneth Deffeyes has a small, crisp section on population control… including
“I would not be surprised if our present-day population has to shrink during the next few hundred years.
Of course, the methods for human population control are enormously controversial. One contraceptive measure seems to be humane and acceptable: If you teach calculus to teenage girls, they go on to have far fewer babies. Calculus is the contraceptive of the future. It doesn’t work for boys.”
Somewhat related, getting rid of dung burning stoves would probably be the most empowering thing that we could do for women in South Asia as well as cutting down on the Asian Brown Cloud.