Why is there a discrepancy between the time it took for modern man to reach its first billion and the time it took for him to reach his 2nd billion?

1 Answer
Dec 20, 2017

Because it is an (approximately) exponential growth in population.


The time required to reach each successive billion would also fall I guess, though other factors have come into play since the advent of effective contraception (thankfully) and the rising notion that women are in charge of their own bodies & reproductive rights are not a God-given patriarchal right.

This is an interesting graph to ponder:


Taken from : https://www.ck12.org/book/CK-12-Earth-Science-Concepts-For-Middle-School/section/11.11/

And this gives a broader perspective: