I have some lovely, well meaning, liberal, environmentalist friends who every now and then start bitching about population control. Whenever I hear population control I hear a dog whistle for "Why do poor brown women keep popping out babies they can't afford" because if these well meaning liberals were really serious about population control they would get vasectomies at puberty.
The thing is, I understand carrying capacity and what happens when a society exceeds carrying capacity (either there is war which decreases the number of people in a system, a new technology has to be invented to change the carrying capacity, or the civilization collapses). I get that we are looking at a future where oil has or is about to peak and global warming is going to have serious effects on food production and water resources (just look at the current drought in the south east ). But what does not work to keep populations from booming is hand wringing by imperialist countries over exploding populations in India and China. Shaming women for doing one of the few things that they are ever given any credit for in misogynist societies doesn't work. Limiting assistance funds so that more people will starve or die of disease doesn't work. Hell, even China's one child per family program hasn't worked at keeping fewer children from being born. It just lead to girl babies being abandoned in favor of boy babies.
What works (and works VERY quickly- within one generation usually) is to give women access to education and economic opportunities. Women who have opportunities to do something other than being a mother will choose those options and women who choose to have children and an education will have fewer children. Period. No hand wringing. No guilt. Just education and economic opportunities. It's very simple.
And while you're thinking about all those "women having babies they can't afford" maybe you should take a look at these numbers. The situation may not be as dire as the hand wringers suggest.