The current main driver of human population growth is not new births, but the cessation of "early" death. Almost all countries now have birth rates below replacement levels-- well below if one includes pandemic or disaster induced loss.
Note that environmental disease implies that many of these older people will be on disability.
The clear picture of the future is a world of elderly.
Japan's decades long recession correlates to its demographic aging and falling population.
Old societies trend to have high tax rates, needed to pay for public services to all the old people. But this induces high youth unemployment.
We have a pressing need to recreate or economy to incorporate childbirth and childrearing into the economy.
Raising a child is estimated to cost 200,000 dollars, before college. The lost income from the caregiver raises this to over one million. Yet the economic benefit is near nill. Contrast to an agricultural society where the children provide a net economic benefit from their second decade.
Increased television viewing is strongly correlated with decreasing birth rates, both accross regions as tv is introduced and within families, comparing the number of hours watched with the number of children.
My rather grim prediction: society will cease to value and respect the elderly. In rural france 100 years ago they were also a burden, and were encouraged to starve so the rest would have enough food for the winter.
