Andrew: I agree completely that population growth is not necessary for prosperity and that immigration is not the answer for the adjustments demanded by lower fertility rates. But the way it’s happened in China really is a problem for them — the rapidity of the fall in fertility and the fact that, as Nick Eberstadt has been pointing out for years, China will grow old before it gets rich, whereas Japan etc. grew rich first, then old, giving them the economic and technological capacity to make the necessary adjustments.