China to begin two-child policy

Its not really a strange choice, its been "1 with lots of exceptions that mostly make it 2" for some time (there were exceptions with a limit of 2 instead of 1 for many rural areas, for families where at least one parent was an only child, etc.) Going to 2 is a pretty obvious simplification that doesn't really change much except the degree of administrative overhead, plus the policy has hurt perception of China in the developed world, and changing it to two from one along with well-managed press relations get you lots of "China to end one-child policy" headlines around the world, and with most people not reading below the headline, that's a huge propaganda win for doing essentially nothing but making a totalitarian policy administratively simpler.

And, really, it was always the plan: the OCP was originally conceived of as a single generation policy to bring the population down, which would be replaced with a stable population policy; it didn't exactly work out that way in a crisp sense, but a going from a one-child policy with very limited exceptions, to a growing set of exceptions, to finally a two-child policy is, in outline, generally consistent with the original blueprint.

> There is obviously some natural limit on human population, but I don't think we're near it.

The practical limit is going to be dependent on pre-existing environmental conditions, technology and distribution of lifestyles and other factors; its a moving target. (And not necessarily moving consistently in one direction.)

> The fact that we hear less concern about it is says something interesting about the zeitgeist. think people believe in technological progress more in 2015 than they have since the space age and nuclear age of 50 years ago, maybe more than ever.

I don't think that's the issue. I think that the fact that Gen X and the Millenials have been less economically secure than preceding generations (reversing the trend toward greater security) means that increasingly, people are focused on more immediate, personal concerns. Plus, to the extent that there is a concern for broader, global environmental issues, the focus has been climate change rather than overpopulation (the two concerns overlap considerably, but climate change is more specific and concrete than generalized carrying capacity concerns.)

> At our current rate (ignoring the projected gradual reduction) we'll double every 65 years.

And, IIRC, in the mid-1960s, that was about 32 years. Which difference also contributes to the reduction in concern for overpopulation since then: we may be closer to whatever limit exists, but we're approaching it much more slowly now and that rate is still dropping.

I'm really unsure what point you're trying to make.

Larger creatures, and those higher on the food chain, having greater access to resources and higher survival rates, invest more in fewer children. Smaller creatures, with lesser access to resources and higher mortality rates, invest less in more children.

A rabbit doe can theoretically have 480 offspring, at 12 per litter, 10 times per year, over 4 years. That's the kind of thing you might do if 98% of your kids get eaten, because you will still have 10 left. Rabbits can also abort their litters when stressed.

An elephant might have one calf every four years, over 55 years, or a maximum of 14 children. That's what you might do if only one other species can reliably kill any of you, and you expect all of your babies to survive to adulthood.

With humans, the observed historical behavior is that poor or uneducated humans are relatively fecund, producing 8-30 children per pair, occasionally with multiple births. As wealth and education increase, and particularly when child mortality drops and elder care becomes socialized, birth rate drops down to the population replacement rate (or below). Middle-class first-worlders usually have 0-4 kids.