The global population pyramid
My concern is that population will shrink after 2100 globally but it will already be shrinking in the rich countries long before that.  And all indicators right now is that shrinkage will speed up.There is something wrong with rich modern secular society here or anywhere (it happens to all societies right now whether they are European, Japanese, Chinese, etc) in that it currently leads to sub replacement reproduction.  This is the next global issue as it will lead to instability in modern rich societies in that they are not sustainable.Japan is the future of all other rich societies, rapid shrinkage if you exclude immigration.And if you encourage immigration as the solution to shrinkage you end up with rising racism and other reactionary trends to these changing demographics.Right now the only societies that are growing or even stable are either developing/poor or highly conservative/religious societies.If we do not address this issue then the world's future is likely poor or highly religious (most likely both) as demographics is the future whether we like it or not.Also societies with shrinking populations will tend to have horrid economies and probably negative growth as the pyramid is inverted.  Probably again like Japan.