65G and Future Urban Warfare

[stanc]

So if life span was halved it wouldn't effect the population either?

As it is, only a small percentage of women who give birth are older than 35, and almost none who are older than 45.

If life span were halved, it would prompt women to have children earlier in life, as was actually the case prior to a century or so ago.

So, I would expect the result of your hypothetical would be as it was historically: A gradual increase in population over time.