59
submitted 1 month ago* (last edited 1 month ago) by notsofunnycomment@mander.xyz to c/nostupidquestions@lemmy.world

After watching this video I am left with this question.

The video ultimately claims that humans will not disappear, but doesn't do a great job explaining why.

Correct me if I'm wrong, but for the (or a) population to be and remain stable, the total fertility rate needs to be equal to the global replacement rate (which recently was 2.3).

And since the total average fertility rate appears to be currently at this 2.3, any drop in the fertility rate in place A would have to be compensated with a rise in the fertility rate in place B (assuming that, at some point, we would like to stop population decline)?

I guess one way for a population to remain stable, while women are having fewer than 2.3 children, would be to have fewer men? If a population has 100 women and 10 men, each woman would only have to have on average (a bit more than) 1.1 child? (Which would of course also require a collective form of prenatal sex selection.)

I realize that would be bonkers and unethical. Just wondering out loud.

top 22 comments
sorted by: hot top controversial new old
[-] Sgt_choke_n_stroke@lemmy.world 27 points 1 month ago

No, the only people complaining about replacement rates are governments that are in bed with corperations that need endless growth to feed thier capitalists machines.

[-] jaycifer@lemmy.world 20 points 1 month ago

Let me spoil part of the Foundation series for you. In one book, the cast visits a planet where they encounter one person with psychic powers surrounded by robot servants. He reveals that the planet is evenly divided by I think 128 people like himself who want for nothing and live comfortably. They only reproduce asexually, and only in preparation for their own death or when another dies.

What this illustrates that’s relevant for you is that yes, not hitting the replacement rate could lead to significant population decline, but only until people are comfortable enough and want to have kids or feel it is the best way to maintain their way of life (think farmers having kids to help on the farm).

[-] Mediocre_Bard@lemmy.world 18 points 1 month ago

If a generation is 25 years, there 7.9 billion people on Earth, and the replacement rate is 1.0, then humans will disappear in about 800 years.

If we enforced a 1.0 replacement rate for two generations, the global population would decrease by 75%, leaving 1.9 billion people in play. This is the global population in 1919. If we go three generations, we could get down to 985ish million prople.

That would be amazing for our climate goals and would be considered ethical and humane by most.

[-] lovely_reader@lemmy.world 11 points 1 month ago

Would the shrinkage in the labor force make it impossible to provide end of life care and financial support as the larger generations age?

[-] Mediocre_Bard@lemmy.world 8 points 1 month ago

Yep. We would have to back to villages at some point.

[-] lovely_reader@lemmy.world 2 points 1 month ago

Would smaller groups feel a reduced strain from that?

[-] Mediocre_Bard@lemmy.world 3 points 1 month ago

Only if they tried to hold to our standard of living. If they adapted, which I suppose that they would, the only stress would be seeing society thin out around you.

[-] Spacehooks@reddthat.com 4 points 1 month ago
[-] yes_this_time@lemmy.world 6 points 1 month ago

Restricting reproductive rights is not ethical.

[-] LordGimp@lemm.ee 7 points 1 month ago

Unlimited reproductive rights is also unethical. Unlimited growth is not sustainable in a finite environment. As masters of our environment, it is our moral responsibility to ensure our existence does not destabilize everything else. We've done so poorly as a species that the world is about to undergo a cataclysmic shift.

[-] yes_this_time@lemmy.world 1 points 1 month ago

Agreed we are not in a good spot and unlimited population is not sustainable. However, sex education, access to birth control, and strong women's rights is the answer in my opinion not 'enforcing' limits - which reads as an authoritarian dystopia to me. Economic growth is good as long as it's decoupled from natural resource use/impact.

[-] daq@lemmy.sdf.org 1 points 1 month ago

What if selection is truly random?

[-] Fermion@feddit.nl 14 points 1 month ago

The human population isn't homogenous. Some regions and cultures have a lot more children per woman than others. So some demographics will experience population decline and others will continue growing. Overall, the world population may go into decline, but we are a very long way away from anything resembling extinction.

[-] dhork@lemmy.world 6 points 1 month ago

So, as long as some humans are successfully making new humans, whether or not the rate is exactly 2.3 is irrelevant. World population has been skyrocketing for the past 100 years. It wouldn't be the worst thing in the world for that to backslide a bit. It can probably go down 5x and we'd still feel like the place is crowded.

The only thing to worry about is some widespread event that affects fertility workdwide. Like what if these micro plastics are really getting into our testicles and reducing sperm counts? They are getting everywhere. If men everywhere started shooting mostly blanks then we would all be in a panic.

[-] NoIWontPickAName@kbin.earth 5 points 1 month ago

They’re not blanks.

It’s tactical chaff to avoid detection until one of the real warheads strikes home.

[-] iiGxC@slrpnk.net 3 points 1 month ago* (last edited 1 month ago)

The replacement rate isn't static. It depends on both how many people exist and how many people are having babies and how many babies they're having. If the total number of babies per year stays constant, then whether it's below or above the replacement rate depends on the size of the population. So for a hyper simplified example, if 100 babies are born per yer, that's below replacement for a population of 110, but above replacement for a population of 90, but overall the population size will trend towards 100. Obviously real life is way more complicated, but even if the birth rate is low now, it's far more likely we're just moving towards a different population size, not a population of zero

[-] notsofunnycomment@mander.xyz 1 points 1 month ago* (last edited 1 month ago)

Expressed as "the average number of babies that an individual woman needs to have for a certain population to stay the same size", the replacement rate should not depend on population size, right?

If you express it as an absolute number (e.g. number of babies per year) than obviously it will depend on population size.

From what I understand, the replacement rate (expressed as the average number of babies that an individual woman needs to have for a certain population to stay the same size), depends mostly on what percentage of people die before they (can) have babies.

[-] teft@lemmy.world 2 points 1 month ago

As the population declines we would probably reach a point where we have to go back to agrarian societies and those pretty much need a bunch of child workers working the farm with the parents.

My thought would be no, we won't disappear unless it's a cataclysmic event that just wipes us all out at once. Also if we can get off this rock and establish a base somewhere else like the moon or mars that increases our chances of not being extinguished even higher.

[-] notsofunnycomment@mander.xyz 1 points 1 month ago

Thanks all for your replies. Interesting.

I'm a bit surprised that nobody comments on the matriarchal speculation at the end. You're all fine with that?

[-] sanguinepar@lemmy.world 3 points 1 month ago

I think if you hadn't described it as bonkers and unethical you might have had some views on that! ;-)

[-] Deestan@lemmy.world 1 points 1 month ago

I’m a bit surprised that nobody comments on the matriarchal speculation at the end. You’re all fine with that?

Mathematically, I am not fine with that. The only way to have fewer men would be late-stage abortion or to murder newborns. Each woman would need to have 1.1 (surviving) children but still 2.3 born or nearly born children. While this may raise some ethical questions by itself, the greater crime is that it artificially inflates a metric without achieving the stated goal. It is lie by misapplication of statistics.

[-] notsofunnycomment@mander.xyz 1 points 1 month ago

That's why I said:

Which would of course also require a collective form of prenatal sex selection

If the goal would be to have a stable population size but with fewer births per woman, I think a collective form of prenatal sex selection (of the kind I describe above) would work.

What this sex selection would look like would be another issue. Whether externally fertilized embryos are selected before they are placed in a womb, or whether it would involve forms of abortion (or even infanticide): it's up to your imagination.

But there are no lies, nor any misapplied statistics?

this post was submitted on 26 Jul 2024
59 points (100.0% liked)

No Stupid Questions

35209 readers
1136 users here now

No such thing. Ask away!

!nostupidquestions is a community dedicated to being helpful and answering each others' questions on various topics.

The rules for posting and commenting, besides the rules defined here for lemmy.world, are as follows:

Rules (interactive)


Rule 1- All posts must be legitimate questions. All post titles must include a question.

All posts must be legitimate questions, and all post titles must include a question. Questions that are joke or trolling questions, memes, song lyrics as title, etc. are not allowed here. See Rule 6 for all exceptions.



Rule 2- Your question subject cannot be illegal or NSFW material.

Your question subject cannot be illegal or NSFW material. You will be warned first, banned second.



Rule 3- Do not seek mental, medical and professional help here.

Do not seek mental, medical and professional help here. Breaking this rule will not get you or your post removed, but it will put you at risk, and possibly in danger.



Rule 4- No self promotion or upvote-farming of any kind.

That's it.



Rule 5- No baiting or sealioning or promoting an agenda.

Questions which, instead of being of an innocuous nature, are specifically intended (based on reports and in the opinion of our crack moderation team) to bait users into ideological wars on charged political topics will be removed and the authors warned - or banned - depending on severity.



Rule 6- Regarding META posts and joke questions.

Provided it is about the community itself, you may post non-question posts using the [META] tag on your post title.

On fridays, you are allowed to post meme and troll questions, on the condition that it's in text format only, and conforms with our other rules. These posts MUST include the [NSQ Friday] tag in their title.

If you post a serious question on friday and are looking only for legitimate answers, then please include the [Serious] tag on your post. Irrelevant replies will then be removed by moderators.



Rule 7- You can't intentionally annoy, mock, or harass other members.

If you intentionally annoy, mock, harass, or discriminate against any individual member, you will be removed.

Likewise, if you are a member, sympathiser or a resemblant of a movement that is known to largely hate, mock, discriminate against, and/or want to take lives of a group of people, and you were provably vocal about your hate, then you will be banned on sight.



Rule 8- All comments should try to stay relevant to their parent content.



Rule 9- Reposts from other platforms are not allowed.

Let everyone have their own content.



Rule 10- Majority of bots aren't allowed to participate here.



Credits

Our breathtaking icon was bestowed upon us by @Cevilia!

The greatest banner of all time: by @TheOneWithTheHair!

founded 1 year ago
MODERATORS