An economist says most global population growth estimates are far too high, the data shows population peaking around 2060, and at 2.2 the global fertility rate may already be below replacement rate
The figures for South Korea are quite stark. They've engineered a society where they'll shrink to 20 million in size from today's 51 million. His figures rely on the average human life expectancy staying at 85. It's possible in decades to come that may exceed 100. It may not, but there are lots of people working to make it happen.
shrink to 20 million in size from today's 51 million..
Imagine, if you will, a world where housing prices weren't cost-prohibitive and there exists enough agricultural land to feed everyone without having companies like monsanto destroying the ecology.
Lowering populations should only be scary if you derive your income from the labor of the masses or plan to derive your income from the labor of the masses.
If you believe their figures, it's notable that although North Korea has about half the population of the South, it currently has more babies. Could lead to interesting situation regarding potential re-unification (although not likely any time soon...).
I wonder if they might actually allow immigrants, while the birth rate other places is still higher. They have less of a reputation for xenophobia than, say, Japan.
If we get the lower end of these projections, you might plausibly live to see a world with a billion people less than now, but to see a world with less than a billion total you'd have to have an extremely long lifetime, which implies some medical breakthrough, in which case, unless you have some super-exclusive access, the population would stop declining, just get super geriatric. I suppose there are other ways to do get there, such as global nuclear war, but even that might let quite a few people continue in the southern hemisphere.
IIRC the people at the UN said something similar. They gave a few projections, and commented that the low ones seem most likely and might still be too liberal.