> Just because Earth's population flatlines at 10m, doesn't mean humanity is heading straight for extinction
By the time the population flatlines (at 10B) it will be with a pretty old population already. Many countries have a birth rate < 1.3 and many more are headed that way. That means after every 30 years or so, the number of babies born every year will decrease by 35%. Every 30 years. This is already very noticeable in e.g. South Korea, which last year had a birthrate of 0.8 I believe, where schools are now closing in droves.
And the problem is, none of the mechanisms that are causing birthrates to plummet are showing any signs of slowing down or reversing. The countries with higher birthrates right now are just further back on the curve, they'll be where we are soon enough. It might be that the reasons for decreasing birthrates are things we're not willing to give up, like improved quality of life of singles, increased education and equality between the sexes. We'll see if natural selection will act quickly enough to produce people with a stronger instinct for having kids, but then the question is why hasn't this already happened, as birth rates have been declining for the past century while living standards have increased immensely. As the number of people choosing to have zero kids rather than just fewer increase, perhaps this will put the pressure on in a way it hasn't yet.
By the time the population flatlines (at 10B) it will be with a pretty old population already. Many countries have a birth rate < 1.3 and many more are headed that way. That means after every 30 years or so, the number of babies born every year will decrease by 35%. Every 30 years. This is already very noticeable in e.g. South Korea, which last year had a birthrate of 0.8 I believe, where schools are now closing in droves.
And the problem is, none of the mechanisms that are causing birthrates to plummet are showing any signs of slowing down or reversing. The countries with higher birthrates right now are just further back on the curve, they'll be where we are soon enough. It might be that the reasons for decreasing birthrates are things we're not willing to give up, like improved quality of life of singles, increased education and equality between the sexes. We'll see if natural selection will act quickly enough to produce people with a stronger instinct for having kids, but then the question is why hasn't this already happened, as birth rates have been declining for the past century while living standards have increased immensely. As the number of people choosing to have zero kids rather than just fewer increase, perhaps this will put the pressure on in a way it hasn't yet.