We may not make 9 billion. And we'll peak sooner than expected.
I write about this every now and then, because human fertility is falling faster then most demographers expect. Using the CIA Factbook for data, the present total fertility rate for the world is 2.47 births per woman that survives childbearing. Last year it was 2.50, and in 2006 it was 2.90. 2.10 is replacement rate. At the current trend, the world will be at replacement rate in 2022. That’s a lot earlier than most expect, and it makes me suggest that global population will top out at 8.5 Billion in 2030, lower and earlier than most expect.
Have a look at the Total Fertility Rate by group:
This is more evidence we are throwing the "9 billion by 2050" around in agriculture too casually. As wonderfully explained by this chart and better by this video.
I would suggest not only will we have enough land and water, less intensive diets in the developed world will ease the food squeeze on poorer countries. A little less waste and presto the food shortage hysteria is revealed as overhyped. One caveat: I hope Canada and Siberia can gear up to be the new grain producing centers as the climate changes.
It is hard for us to imagine a falling population in the US, but we farmers can kinda sense it as rural America depopulates. My sons and grandchildren could experience it in a completely new kind of world - a demographically top-heavy world of too many geezers and too few teenagers.