[defrost]

> There's little evidence to support the theory that at some point in the future, little girls will all suddenly decide to buck the trend set by their mothers, grandmothers, great-grandmothers, and all the adult women they see around them in the world, ..

What nonsense.

The 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.

BTW, this focus you have on breeding "little girls" is distasteful to say the least.

> those girls would need to have 3 or 5 or 8 to make up for those who do not.

Only if the world is to return to the present 8+ billion after a fall below.

Should numbers slowly decline down to, say, 1950s world population levels and mean reproduction rates go to 2.1 then things will stabilise.

> If neither of these things happen, population cannot stabilize.

Faulty logic, as already explained.

> And why should any human ever give a shit about whether these non-human organisms thrive

My response was to a human who was waxing lyrical about 3.7 billion years of life, an infintesimal number and tonnage of which was actual humn life ... you should ask them why they care about other lifeforms.

You might perhaps ask yourself why you do not.

[Aerroon]

>The 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.

From the graph I saw the total fertility rate in the US has been falling since 1800 (start of the graph). It briefly improved after WW2 for a bit and then started falling again. There was another brief increase at the end of the 90s and it's been dropping to historical lows ever since. It's not just two generations - it's 200 years and possibly longer.

The graph: https://infogram.com/20221003_gygi_vanessa_calder_fertility-...

[defrost]

It would appear that we both agree that population changes rates can alter over time and that it's happened in the past and can happen in the future then.

Unlike the other commenter who has claimed that once a rate has been set it cannot change.

[NoMoreNicksLeft]

> 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.

[defrost]

> Are you daft?

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.

[NoMoreNicksLeft]

> That magic number can change.

Which goes back to my original comment, where I talk about for it to change, the little girls of the youngest generation have to grow up and choose to have more children than their parents. They all have to choose this simultaneously, or the few that do choose it have to choose to have far, far more than 2.1 themselves.

Both of these scenarios are so outlandish, that you keep dancing around it, pretending that I'm describing it incorrectly. You don't want to think about it, or don't want others to think about it, or you just aren't capable... I can't tell which.

It'd be laughable, if I didn't think you were an enemy of humanity.