I've got whiplash from the speed at which we've jumped from overpopulation doomsday to demographic degrowth doomsday.

It seems likely we lend too much credence to experts ability to model complex systems over a long period of time.

That's the thing with exponentials, they are very hard to predict. We know that in general, exponential growth is unsustainable, and there has to be an inflection point, but where? It is usually difficult to know until the last moment, and even a small difference in time on where you predict the inflection point is can make a massive difference.

Look at COVID for instance, not the first novel coronavirus infection, it only took days to go from "maybe it is like the other ones that infected a few thousand people" to "everyone on the planet will get it", because the start of the curve looks the same.

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glenstein 8 hours ago | parent | prev | next [-]

Well I wouldn't both-sides this one. 2020s population forecasting is better than 1960s forecasting, the latter was repudiated and the former is correctly modeling basically everything. Demographic decline really is happening and has reasonably well understood mechanisms.

I suppose I would separate out some of the more extreme predictions about demographic collapse in Russia or China. I'm not sure what to make of those or if they're similarly credible to other kinds of population forecasts.

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satvikpendem 9 hours ago | parent | prev | next [-]

You got whiplash over the speed of...a few decades? Malthusian theory had been proven wrong and people have known this since last century.

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slibhb 8 hours ago | parent | next [-]

The population hysteria from the 60s was proven wrong a long time ago but it's still pretty influential. E.g. it's not uncommon for millenials to talk about not wanting children because of overpopulation.

It takes a long, long time for new ideas to diffuse through society. Most people are not paying close attention to the cutting edge.

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awongh 8 hours ago | parent | next [-]

Even if there's a lot of scientific evidence, statistical proof etc. it's sort of surprising to me that when chatting with people all over the world (in dense cities and also in non-dense areas) how often I hear the sentiment that "there are too many people" and get the sense that they do mean that there's too many people in the world (not just within the surrounding 5-10km which might actually be true).

This might also be one of those things that aligns with people's experience of the world, and the de-population thing is inherently counterintuitive unless you are, by definition, outside the norm- that is, you would only ever notice this if you live where people already don't live. (rural Japan, etc.)

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neutronicus 2 hours ago | parent [-]

I guess I don't understand what's supposedly been proven wrong?

There seem to be real concerns about whether the environment on Earth can sustain the impact of human society in its current form, and the population is an obvious lever to scale that impact.

I guess what's "surprising" is that birth rates are responding to the pressures I'm alluding to? Rather than just continuing runaway exponential expansion?

	▲	amanaplanacanal 2 hours ago \| parent [-]
		I think people are talking about two different things. The initial panic was that agriculture could not scale to population growth, and millions would starve. That part turned out to be quite seriously wrong, the reason people starve is that they have really crappy governments. The idea that a growing population has quite serious effects on the natural environment hasn't been proven wrong. Trying to get the entirety of the third world up to first world living conditions is putting a serious strain on natural systems. Having a lower population would probably help with that problem. The current panic around falling populations seems to have two drivers: economic systems that are built as essentially a ponzi scheme, like many retirement plans including social security, and a pretty racist idea that we need to have a lot more white babies to keep brown people from taking over.

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boelboel 8 hours ago | parent | prev | next [-]

I think for most millenials it's an excuse not really the actual reason they don't want/get kids (although i think there's a few actual believers).

	▲	bombcar 2 hours ago \| parent [-]
		It's amazing how many people don't realize that people make a decision, and then find reasons for it.

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triceratops 3 hours ago | parent | prev | next [-]

> The population hysteria from the 60s was proven wrong a long time ago but it's still pretty influential

I wonder if people in the 2080s will say that about the underpopulation hysteria from the 2020s.

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Supermancho 3 hours ago | parent [-]

The next 50 years will cause all industrial countries to face an irregular demographic profile, weighted toward the elderly. The median age in China is almost 41, while the US is reaching 39. In the US, the elderly (65+) will be almost 1 in 4 of the population ~2050. In contrast, boomers were 37% of the US population at their height (elderly were ~9.5%).

There is no underpopulation hysteria. However, the math around demographics is settled.

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triceratops 3 hours ago | parent [-]

What's the problem? Robotics and AI will transform elder care as well as the workforce.

There will be fewer taxpayers. That's not a problem.

"Anything we can do, we can afford".

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MentalM 2 hours ago | parent [-]

> Robotics and AI will transform elder care as well as the workforce.

Or not. Incentives are confronting it.

It is very likely that one day productive members of society just decide that it is not very advantageous for them to provide for more numerous old people, and that it is them, who holds the power and have ability to decide what to do. So f.ck democracy, f.ck elders, let them enjoy the world they have created. Sociopolitical environment probably will have way grater affect on an elder care than AI and Robotics.

> "Anything we can do, we can afford".

Exactly. And the elders can do nothing. I mean they can use their amount and vote, but it will only intensify the process

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triceratops 2 hours ago | parent | next [-]

> It is very likely that one day productive members of society just decide that it is not very advantageous for them to provide for more numerous old people

It is unlikely because productive people tend also to have some amount of foresight. Enough to know that they will also be old one day.

> I mean they can use their amount and vote, but it will only intensify the process

Process of what?

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MentalM an hour ago | parent [-]

> productive people tend also to have some amount of foresight

Guess what they will see with that foresight when there are several times more old people who take away most of their earned through sweat and blood resources?

> Process of what?

Social reorganization

	▲	card_zero an hour ago \| parent [-]
		What, what will they see? "That's going to be me one day", or "we need to reorganize this so that I die in poverty"? But take away sounds unfair, and if you're talking about fairness, then fair enough. I can't argue with fairness, until you reveal what the idea is in detail. Oh, but I'm not thinking this through: there are of course fewer young people, and if they started reproducing a lot then they'd get to neglect the elders now and be looked after when they're older. Perhaps that's the plan. I guess that explains "the world they have created" too: they didn't create enough young people, you mean.

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card_zero 2 hours ago | parent | prev [-]

> and that it is them, who holds the power

You mean, young people hold the power? Or young people will decide that they hold the power? Well whoever holds the power, I hope they agree that we all have rights.

> f.ck elders

Specifically what form of f.cking? Do you just mean "don't subsidise their care through tax?"

> let them enjoy the world they have created

You mean the world with lots of elders? They created this how, by deliberately being born?

> the elders can do nothing. I mean they can use their amount and vote, but it will only intensify the process

Their "amount", their money? Or their population size, relevant to voting, I guess that's what you mean. Both sound quite influential unless you want to make them non-people for being old. Now admittedly old people are ugly and smelly and boringly slow, but that last shortcoming can be mitigated by exoskeletons and hard drugs, and then they're going to hunt you down and scrag you, that's my prediction. It's as good as any other prediction floating around in this subject area.

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clark_dent 8 hours ago | parent | prev [-]

Millenials talk about not wanting children because they don't want to subject a new generation to this absolute shitshow of a planet, or because they can't afford the time and resources to adequately raise them.

I've not heard anyone talk about an overpopulation problem in 30 years.

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joenot443 8 hours ago | parent | next [-]

I'm a millennial and I really really like this planet. It's my favorite one. My kids are going to like it here too someday, I hope.

My peers who are skipping kids are mostly doing so because their other ambitions don't align with raising a family, which I totally get. It's a huge trade off, I hope it'll be worth it.

	▲	VirusNewbie 3 hours ago \| parent \| next [-]
		>doing so because their other ambitions don't align with raising a family, Are your peers more ambitious than mine or are their ambitions to travel for cheap and watch as much netflix as possible? (This is obviously not true of my coworkers/friends from work who can all afford kids and most choose to)
	▲	RunSet 8 hours ago \| parent \| prev \| next [-]
		"They had such enormous fun that they called for another elephant to come."
	▲	metalman 7 hours ago \| parent \| prev [-]
		gen x here, and my observation is that millenials tend to let there back brain say whatever the 'expected' response is,as having had it barked at them from birth makes it effortless, and then going back to bieng cagey,mildly subversive, and somewhat ferral in there actual lives. point of order : there is NO trade off in getting what you want.

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dofm 8 hours ago | parent | prev | next [-]

As a general rule they won't talk about overpopulation being a problem because they know that the population will likely peak within their children's lifetimes.

They do talk about whether the earth can sustain that population as a reason not to have children. They are correct to. Their children might be the generation who have to explain to their children what fish tasted like.

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UncleOxidant 3 hours ago | parent [-]

yes, this is the thing I'm not quite getting from the "malthus was proven wrong" argument. Yes, technology increased food production, but that doesn't mean there isn't a carrying capacity to the earth. We have overfished. Fisheries are in decline all over. I guess you could say "no problem, we'll have lab created or grown fish and it will be fine" ok, maybe. But it's not going to be the same and the oceans won't be the same.

What I don't get from all of the demographic collapse hand-wringing: Somehow in the 1970s we got by with 1/2 as many people as we have now - why would a long, slow decline back down to that number be catastrophic? Why would stabilizing at a lower population be problematic? Sure, during that decline there's going to be issues, but once you hit a new stable population those would go away.

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thombat 2 hours ago | parent | next [-]

One commonly perceived problem is the increase not just in the fraction of the population that is retired, but how long they will remain retired if provided with adequate care, or (more bluntly) how long it takes them to die compared to previous generations. Here in Germany the social system was established when most people died within two-three years of retirement age. Today they can expect to live for more than fifteen years, thanks in part to more expensive health care (cardiac arrest used to be effectively lethal, if not immediately then through subsequent arrests, now it's generally survivable with expensive care). The current retirees are entitled to this, having paid into the system, but current workers can look upon their own increasing contributions and the overall maths and feel uneasy that though paying more they may receive less.

The retirement age is now slowly being raised, and given time the system may level, but in the meantime "issues" will indeed present.

	▲	UncleOxidant 2 hours ago \| parent [-]
		Raising the retirement age is one thing, but finding work for those retirees is another. Ageism is rampant (and especially in tech). Maybe that becomes less of an issue when more of the population is older, but I don't think we're there yet.

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card_zero 3 hours ago | parent | prev | next [-]

The issues might go away sooner than that, because I imagine - naively? - that a society full of old people would put lots of effort into reducing the problems of being old.

Having declined, the population might increase again, and decline again, but with fewer issues the more practice we have. Stability sounds unlikely.

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MentalM 2 hours ago | parent | prev | next [-]

> Why would stabilizing at a lower population be problematic?

1. There are no incentives to stabilize at a lower population. It is not like population are decreasing because of overpopulation.

2. It is workers / welfare recipients ratio that will be the catastrophic problem.

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alexk307 2 hours ago | parent | prev | next [-]

> Sure, during that decline there's going to be issues, but once you hit a new stable population those would go away.

I think you're compressing a lot of hardship into "issues"... It's not about total number of people, it's about demographic distribution. If half of your population is at retirement age, who is going to take care of them? Who will be working to generate tax revenue to provide the social services that you expect?

Also populations don't just stabilize, they feed back off of themselves. If half of your population isn't procreating, you get fewer and fewer babies which is a vicious cycle. There aren't many policy levers to pull during demographic free fall.

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amanaplanacanal 2 hours ago | parent [-]

Easy, raise the retirement age.

The problems you are expecting from demographic free fall aren't going to happen for generations, and at any point during that time people could decide to start having more babies.

	▲	UncleOxidant 35 minutes ago \| parent [-]
		> Easy, raise the retirement age. I'm not sure it's that easy. There are a lot of people who aren't able to work as they get older for medical reasons. And there's a lot of ageism that keeps older people out of the job market. Maybe that ageism lessens as the population ages, but we're not there yet.

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bayarearefugee 3 hours ago | parent | prev [-]

> > Somehow in the 1970s we got by with 1/2 as many people as we have now - why would a long, slow decline back down to that number be catastrophic?

Because we've built an economic system based on the idea that you must, at all costs, grow. Stable success is insufficient and will be seen as failure.

And then we spent many decades programming people to believe this is the only thing that can possible work.

Nothing natural about this at all, it is just the result of the cult of capitalism.

	▲	card_zero 3 hours ago \| parent [-]
		Have we, though? Governments rely on economic growth to fund their plans. That means economic activity has to grow, which means ... something ultimately rather unclear about what people around at the time consider wealth to be. It doesn't mean "everybody into the spawning pools and get busy".

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8 hours ago | parent | prev | next [-]

[deleted]

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slibhb 8 hours ago | parent | prev [-]

> Millenials talk about not wanting children because they don't want to subject a new generation to this absolute shitshow of a planet

They often list overpopulation as a reason. But yes, it's not the only reason they give.

As an antidote to this kind of mindless negativity, just consider whether any individual human is happy to have been born. It seems very clear to me that most people enjoy being alive and so having children is moral on utilitarian grounds.

	▲	amanaplanacanal 2 hours ago \| parent \| next [-]
		Bad argument. You could have had even more children, is the fact you didn't immoral? What kind of monster are you?
	▲	8 hours ago \| parent \| prev [-]
		[deleted]

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StableAlkyne 8 hours ago | parent | prev [-]

> Malthusian theory had been proven wrong

It was never proven wrong, as much as the world changed in a way that invalidated it.

The entire idea was that population growth was an exponential function, whereas agriculture output was a linear function. There would have been famine if nothing had changed, because there is only a certain amount of physical labor a person is capable of doing, which has to be divided between the farming, logistics, and cooking of the food.

What happened was that a century later we got mechanized farming and synthetic fertilizer, decoupling agricultural output from the population. Now a single person can do the work of thousands, and every year that number grows due to technology advances. It is too expensive to set up fully automated farms on the industrial scale, but it is technologically possible.

But none of that invalidates his idea. If you believe that an exponential function and linear function sharing a point at (0,0) must cross each other (subject to other reasonable conditions like not having crossed yet, the linear having a positive finite slope, etc), then it is not logical to reject Malthus. It just no longer applies because we decoupled our food production capacity from the population size.

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bobson381 an hour ago | parent | next [-]

And because of this, many will starve as a result of oil shocks from the disruption and chaos in the gulf region. We solved the trolley problem by throwing a magic lever that puts five descendants of the original person a ways down the tracks.

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tikhonj 3 hours ago | parent | prev | next [-]

You also have to believe that population growth is fully exponential. But in practice it looks more like a logistic curve, and the factors that slow it down are a lot less dramatic than resource starvation or violence.

	▲	StableAlkyne an hour ago \| parent [-]
		You do not have to believe population growth is fully exponential for it to be a valid conclusion. You just have to have human population grow faster than agricultural capacity, which it was. Additionally, it is reasonable in the 1790s to assume exponential population growth. It would not be until the 1830s that Verhulst would even model it as a logistic curve. Moreover, human population growth really was on a roughly exponential trajectory until very recently. Obviously we did not experience such catastrophe. But it's also a bit wrong to call it "invalid" when it was a completely logical conclusion to make. If we're going to allow him to invent a magical technology that addresses it in 1798, then all reason goes out the window.

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simonra 7 hours ago | parent | prev | next [-]

As long as I keep hearing about the need for reducing meat consumption and supply chain slack (food waste), I'm inclined to think Malthus was right despite the limit turning out to be soil capacity rather than labour capacity.

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glenstein 8 hours ago | parent | prev | next [-]

I mean insofar as the idea is about contemplating those mechanisms in the abstract, sure. But insofar as they were predictive or an attempt at a descriptive characterization of where populations would actually go, clearly it didn't hold. And if it didn't hold because it's true on it's own terms in some abstract sense, so much the worse for its inability to model changes that would prove to be relevant to actual population dynamics.

It's also not just that we accommodated explosive populations but that eventually birth rates really did simply start slowing down for discernible reasons that future models were capable of integrating. Even if we continue to have technology that would give us the capacity to accommodate future increases in population, those increases are no longer happening.

	▲	StableAlkyne 2 hours ago \| parent [-]
		> And if it didn't hold because it's true on it's own terms in some abstract sense, so much the worse for its inability to model changes that would prove to be relevant to actual population dynamics. That's a bit unfair to Malthus though; sure it was the enlightenment, but all he could rationally go on was to assume that the last 2000 or so years of civilization would be similar to the next, in terms of food and population growth. What would be abstract would be to make the assumption that unprecedented technological advancement would be made in the next hundred years, bordering on ( to what Malthus would be) magic. You can assume any problem will be solved if you also assume a technology will be invented to fix it. But that's not a reasonable approach to make if you have no reason to believe it is possible.

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satvikpendem 5 hours ago | parent | prev | next [-]

I mean, by proven wrong that's what I mean. I'm not talking about the theoretical mathematics but the real world application of theory in which case, yes, Malthus was proven wrong.

	▲	StableAlkyne 2 hours ago \| parent [-]
		I wouldn't say proven or disproven, as much as it became no longer applicable. The world he was modeling in the 18th century is a very different world than we ended up getting. IMO it's neither right nor wrong, it's just a reasonable observation that made sense for the time. It's somewhat analogous to Y2K, in that there were obvious problems that were going to happen. We didn't experience those negative outcomes because immense engineering effort solved the underlying problem. That doesn't mean Y2K was "invalid" or "wrong," just that the problem itself got addressed before it could blow up. Same with Malthus, chemistry and mechanization allowed us to solve the underlying issue of food production scaling slower than population growth.

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jonapro 3 hours ago | parent | prev [-]

[dead]

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ChrisMarshallNY 2 hours ago | parent | prev | next [-]

I think it's simpler than that.

Us "numbers" people consistently fail to take basic human nature into account. Evidence of that, is everywhere; most obviously, in industrial/UX design.

Human nature is raw chaos. I have friends in the fashion industry, and that is an industry where human nature can cost (or make) a company millions of dollars. People that are good at understanding human nature, do well.

It doesn't respond well to number-crunching, though.

Also, as animal populations sometimes demonstrate, fertility can be a function of crowding. Pack a lot of critters together, and they tend to produce fewer new critters. Maybe the same thing happens to us.

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yoyohello13 3 hours ago | parent | prev | next [-]

I think it's the 'doomsday' part that's the problem. Not everything is the 'end of humanity'.

	▲	Muromec 3 hours ago \| parent [-]
		Doomsday scenarios specifically are a distinct mind trap for Christianity-affiliated cultures, which is very visible in US specifically from the media they produce. It's a very appealing narrative.

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randusername 8 hours ago | parent | prev | next [-]

It takes an uncommon breadth of perspective and depth of intellectual humility to contradict evidence it is your job to collect and interpret.

Sometimes the trends of tomorrow just aren't in the data of today.

What modeler in the late 19th century, when children were still economic assets on farms and in factories, could have predicted they would become extraordinary economic liabilities?

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Muromec 3 hours ago | parent | prev | next [-]

>It seems likely we lend too much credence to experts ability to model complex systems over a long period of time.

I swear, half the problems in this world are humanities people doing linear progressions and advising somebody making a policy based on that.

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dsizzle 8 hours ago | parent | prev | next [-]

I think a lot of the difference is due to different groups/lead figures/experts focusing on different concerns, e.g. people like Paul Ehrlich and environmental groups focused on ecological sustainability vs people like Elon Musk and governments focused on economic sustainability

	▲	Amekedl 8 hours ago \| parent [-]
		yup. going by sustainability, we already have too many ppl on this planet. everything else is just "who pays my pension".

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lapcat 8 hours ago | parent | prev | next [-]

> It seems likely we lend too much credence to experts ability to model complex systems over a long period of time.

You say "complex systems" but are actually referring to human behavior.

Humans are unique in that they change their behavior in light of predictions. You can't make a prediction, and publicize that prediction, without changing the system.

From what I've heard, many people are declining to have children precisely because of the environmental effects of overpopulation. There are of course other factors, but that's one factor.

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AndrewKemendo 3 hours ago | parent | prev | next [-]

Assume neither are true and they are both based on faulty models of reality

Think about it this way: the desired population is a sub-function of the desired society that someone is attempting to describe

If the total population configuration is growing faster than your desired population configuration then simultaneously:

1. There’s “too many” people not like me

2. Not enough people like me

Every argument about this is pure chauvinism

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expedition32 3 hours ago | parent | prev | next [-]

Only people who hate immigration think there is under population.

My country GDP growth has been dependent on foreigners since time immemorial.

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dgellow 9 hours ago | parent | prev | next [-]

It’s more that we constantly extrapolate what experts are doing to the real world without taking in account the actual details. A research team comes up with a model that has some specific biases, parameters, etc. it yields some results. The result is then taken completely out of context and applied to a messy dynamic real world situation we don’t even have reliable metrics for. Then it just becomes a fight over narratives

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notnaut 8 hours ago | parent | prev | next [-]

Fear mongering / doomsaying has been a popular human tendency for as long as we have been able to record our interactions.

If you’re vague enough about it, you can never be wrong! And if you’re overly specific and have a modest following of rubes with more money than sense, you can take some of it! A lot of it!!

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thewhitetulip 8 hours ago | parent | prev | next [-]

Exactly!! During my childhood I used to be terrified if population explosion

Now that I have a kid, there is doom over population shrinkage

Sadly this will be used by propagandaists to doubt scientists

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thaumasiotes 7 hours ago | parent [-]

> Sadly this will be used by propagandaists to doubt scientists

Why is that sad? What other conclusion could you draw from the facts?

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the_af 5 hours ago | parent [-]

It is sad because this is how science is meant to work, but propagandists will use it as evidence to dismiss it as some sort of liberal conspiracy. This is what the commenter you're replying to means by "doubt".

Science uses models to make falsifiable explanations and predictions. That these predictions are falsifiable and can be rejected, superseded or require fixing is how it's supposed to work, not an indictment against them.

	▲	MentalM 2 hours ago \| parent [-]
		> It is sad because this is how science is meant to work No, it is not meant to work that way. The situation were formed by pretty predictable and easy to model factors, and if the science have failed even with that, how can we right now trust it with the things that are obviously way harder to predict?

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9 hours ago | parent | prev [-]

[deleted]