| > he very evidence you seek is right here, right now, all about us - a world in which men and women have a reproduction rate lower than than their grandparents and great grandparents. They have clearly bucked the trend of those in times past. Q.E.D. Are you daft? If fertility rates were high in the past, if they were 6 or 8 or 9.7... they could fall for a long time with no decline in population. But once they dip below the magic number of 2.1, then population declines. That's how this works. That's the number of children a woman (every woman, on average) must have for population to remain the same from one generation to the next. I don't know any other way to explain it. You probably think you're intelligent. You followed the teacher's instructions and got an A on math, but you never really understood it. If you follow the recipe, it just poops out correct answers... but here we have a novel problem, and you just can't get it. > Only if the world is to return to the present 8+ billion after a fall below. No. For the population to plateau out and stay the same, they'd need that many. It's how fucking averages work. Either all of them have 2.1, or if only half have children, then they need to have 4.2. And this isn't for the population to grow again. It's for it to plateau out and remain the same as it is. > Should numbers slowly decline down to, say, 1950s world population levels and mean reproduction rates go to 2.1 then things will stabilise. That's the fucking point. If population declines, it's already below 2.1 And if it's below 2.1, that becomes the norm and it never goes back above 2.1. No little girl grows up in a world of childless adults, of the rare "only child", and "only child" herself and says "I think I will do what ever woman I ever knew wouldn't do, and have 2.1". It's a simple fucking idea. > You might perhaps ask yourself why you do not. Because I don't belong to a death cult that hates humanity. I mean, I shouldn't have to say it out loud, but there it is. |
No. I still recall studying population dynamics, predator | prey cycles, etc as part of non linear dynamics in mathematics classes back in the 1980s.
> But once they dip below the magic number of 2.1, then population declines.
That magic number can change.
It's relatively easy for anyone to find observational examples of populations with adaptive reproductive rates.
> I don't know any other way to explain it.
Perhaps you might try studying mathematics.
> Because I don't belong to a death cult that hates humanity.
The question was about life on earth, not specifically humanity, the notion that you belong to a humanity hating death cult is frankly one that would not occur to most people .. but here you are going straight there.