My key point is that I am not suggesting that population decreases as affluence increases. I am suggesting that population decreases as the cost-benefit to the individual of having a child increases, something that naturally happens in the west.

As for wars, no war has ever really reduced popluation. WW2 killed 80 million people, but that’s a drop in the bucket compared to the 2billion odd who were alive at the time, and was far outweighed by the baby boom once the war was over.

I’m not suggesting that it’s a perfect solution, although it is better than anything else. Certainly it is better at popluation control than war or famine.

So what to do?

1) Try to change western society to gain better efficiencies, and ultimately become environmentally neutral. It’s going to be tough. I won’t deny it.

2) Keep working to improve health and education and welfare in the third world. (If child mortality falls then, people have less need to have children, if there is an adequate social security, then people don’t need to have children to look after them in thier old age.

The worst possible outcome for the environment would be if the west were to slip back to an agrarian culture: then it would once again make sense to have a lot of children, and to slash and burn to make as much food as possible.

Let me play devils advocate for a second and say that IMO there is a single very good mechanism for population control, it is simple, effective, and won’t have human rights groups picketing your office.

It’s going to be controversial here, because, while it might slow, or even reverse population growth, but it does cause a lot of other issues:-

It’s called a western free market economy.

My argument is this: Kids are expensive.

In a modern western economy, raising children means either the loss of an income, or paying for child care, then clothing, then education, all of which cuts into the parent’s personal income and freedom, pretty much indefinitely. From this what does the parent gain? Obviously the ability to pass on one’s genes is no small thing, but once you’ve had one, maybe two kids, with today’s mortality rates, then your genetic heritage looks secure. Besides that however, well there isn’t a lot. Modern adults are expected to have the means to look after themselves well into their dotage, with only the slimmest amount of token help from their offspring.

More than two and you get diminishing returns. Each child only adds to the cost, while only increasing your odds(which are already pretty good) of passing on your genes only marginally.

Compare this to an agrarian society with little or no education. There a child is relatively cheap to raise, as you are already growing food, and have no education expenses to speak of. Child mortality is high, and children are expected to look after parents in their old age – children are the parents pension. In that case it make sense for somebody to have as many children as they can, thus population boom.

As for proof, well let me give you this: if you show me a western economy(with a few possible exceptions, and Saudi Arabia doesn’t count, sorry), then I will show you a country that without immigration, or government bribes to have children, can’t maintain its replacement rate, or at least is very close.