There's a story floating around about how new studies show that even if there's another world war, or some mass pandemic, the human population of the world is going to keep on rising. That's true, for most of those who are going to have children in the coming decades are already alive and we've a reasonable enough idea of how many children each of them is likely to have. The bit that caught my eye though is that the paper is edited by Paul Ehrlich. That's usually a sign that there's going to be something wrong with it. And so there is:
Amoral wars and global pandemics aside, the only humane way to reduce the size of the human population is to encourage lower per capita fertility. This lowering has been happening in general for decades (27, 28), a result mainly of higher levels of education and empowerment of women in the developed world, the rising affluence of developing nations, and the one-child policy of China (29–32). Despite this change, environmental conditions have worsened globally because of the overcompensating effects of rising affluence-linked population and consumption rates (3, 18).
It's that "despite" that grates. For while female education and empowerment are indeed correlates of lower fertility, they are not the causes. It is that rise in affluence that is behind all of the three. In a subsistence economy there is no spare capacity to educate anyone, let alone women. And a subsistence economy is also going to be a human and animal powered one, an economy in which there's not going to be much empowerment of the physically weaker sex. It's only when a society gets richer that we can all start, male and female alike, using that attribute that makes humans different, our brains, as we leave the heavy labour to the machines. and it's also that greater wealth that leads to the falls in child mortality, the education of women, those correlates of falling fertility.
That is, Paul Ehrlich is still getting the drivers of human population numbers wrong. Not that we should be too hard on him: probably a bit late in his career for a fundamental rethink, isn't it?