You are talking about chemical pollution (which may indeed play a role), but there are plenty of other kinds of pollution. Light pollution and sound pollution come to mind. Might constant noise and a lack of night darkness make people less interested in sex and child raising? And then there's the issue of overcrowding. I have long suspected that the fertility collapse that we are observing is caused to quite a significant extent by our mammalian instinct against overcrowding. It would go a long way toward explaining why fertility is cratering all over the world, despite major differences in culture. Because all those cultures have one thing in common: urbanization and (therefore) overcrowding inherent in city living.
I also wonder about electro-magnetic radiation. It's been just over 100 year since the first radio broadcast. Now we are constantly bombarded by all sorts of signals. Radio and TV, cell phone, routers, electricity, lighting - and these are just local. From space we are bombarded by various communications and imaging satellites that broadcast in a broad range of spectrums.
There are theories that all this electro-magnetic pollution is what causes migratory birds to fly off course, or the increase in erratic behaviour of large sea mammals, including large beachings. So what could it be doing to us?
Actually, where contraception means are available, it will always interfere with the whole picture as people can much more easily choose not to have children while still having sex as much as they like.
So it would be interesting to look at the trend in areas where contraception is not that common (either for social or cultural reason). Because if the number of children in falling there too, that would mean that either sexual activity or biological fertility are decreasing. If not both.
Beside, at a deep level, overcrowding might play a role on human psychology and behavior. But it might well be a mere corellation. What is the main reason is just wealth? Wealth give access to contraception. But more to the point, children don't generate wealth anymore while they cost and prevent one to fully enjoy wealth.
And then, education, pollution, urbanisation, etc just happen to come with wealth too.
I am not sure there are any *urban* areas anymore in which contraception is not readily available. Maybe some war zones, but wars don't tend to produce baby booms, do they?
Anyway, I'm sure that contraception plays *some* role, but still, why is it that people are suddenly so enthusiastic to use it? I mean, intellectuals used to panic about humans breeding like rabbits and refusing to use readily available contraception. So, what changed? The other thing is that, in the West, people are indeed having less sex than they used to (or at least that's what social scientists keep telling us). And East Asia is kind of like the West, only more so.
I guess it could be possible to study densely populated areas where religion tend to forbid contraception. Then compare with places were traditions or religion is less prevalent. And places where people tend to be richer or poorer. Or more or less polluted.
What religion forbids contraception? Well, there are the Orthodox Jews, for example, but the thing with such religions is that they have a large "defection" rate. People grow up in the religion and then leave if they don't like it. Those who stay are a self-selected sample. If you want an entire *area* (so, you're not focusing on some subpopulation that can be defected from relatively easily), I'm not sure you're going to find it. At least not in urban areas. Well, maybe in Africa. But that's the thing: fertility is falling in Africa, too. Sure, it's above replacement - for now. Well, Korean women had something like 6 children per woman just a couple of generations ago.
My guess is that, fundamentally, it's urbanization. Cities have never been able to reproduce themselves, and they only ever managed to grow due to immigration (from rural areas). The details will vary, but if you cram people into cities, they do not produce enough babies to reproduce themselves. (Of course, replacement rate depends on child mortality, which used to be very high in cities.) If you took away contraception - well, take a look at how that worked out in Romania. Initially, they had a massive baby boom, but then birth rates very quickly started declining again, despite contraception remaining illegal. And of course, Romania became world-famous due to its orphanages...
Actually, I agree with you that urbanization plays a role.
But is it because of some kind of deep unconscious ingrained mammalian mechanism destined to avoid overpopulation ? or because of much more conscious choices linked to very straightforward economic reasons ? or because of a decrease of fertility or even sexual activity due to high level of pollution ?
In other words, before contraception (that is before people could really make choices) and/or before chemical pollution, does urban women give birth to less children than rural ones ? I wonder... Maybe.
"In other words, before contraception (that is before people could really make choices) and/or before chemical pollution, does urban women give birth to less children than rural ones ?"
Good question. Data doubtless exists (at least for Western Europe for the past few centuries), but I'm not familiar with it. Certainly, infant mortality was higher in cities, but I simply don't know about fertility rates. If fertility rates were indeed lower for urban women, that would be evidence for my overcrowding hypothesis.
Wealth or poverty generated by having a large number of children is a complicated matter.
It is easy to imagine how it could be difficult to feed a lot of children. An the issues that may arise when dividing between them the piece of land or the small business that provide just enough for the family.
But on the other hand, when there is no social benefits, medicare or retirement plans, children are the only form of insurance available. So even if it might cost a lot, the sensible thing is to have at least half a dozen, given the fact that a good share of them can die along the way and it's always possible to send some to the army or to the church.
Of course, none of this logic still fully apply in the modern world when society is getting wealthy enough to offer social benefits.
Yes, and the creature world. I had no idea of the importance of light patterns as they change day/night for the creature world until I read this research paper. I wrote this back in the summer as an update on a book review.
"More concerning in my mind is the subtle effect on the scattering of celestial light patterns which regulate behaviour in many species of animals, especially perhaps many insects. I have seen nothing yet on how this is going. See my Reference 4. below, scroll down after my extensive section of footnotes; this is the study referred to: https://bit.ly/45ikDfs" PS The intro gives the gist.
I suppose this can be related, our situation is not so extreme as the total collapse, but interesting because society seems to fall before resources viability affect it.
I usually use that experiment in discussions, I suppose it is not only overcrowd because rats are quite used to really overcrowd situations and paradoxically thrive most in overcrowd and scarce resources conditions, so I find it one of the most intriguing experiments.
I feel like the triggering event is when the survival of the single is no more linked to the colony, cooperation didn't is more the most useful move so a lot of derived habits are erased and rats have a lot of them: they are quite found to get sacrificial individual for exploring new areas, usually the weak ones (not coerced), too old ones in the colony go to feed first on new or strange foods for test them if really eatable, male defend children of any female of the colony and female feed orphaned, they also have some form of tending of the sick...
Broken the link between individual survival and colony unneeded cannibalism also happened in the experiment, stray impulses unlinked and untamed make this too possible!
Statistical data shows that last year of population growth in Serbia was 1991 (0,2%). From that year there is steady decline which is accelerating. Currently Serbia loses between 40 and 50 thousand people per year, a colossal decline for a country of 6,5 mil. I think that in Serbia's case Seneca cliff is proven fact.
Right on the button with the failure / postponement of the preparation for a plastics treaty. Nate Hagens has just done a Great Simplification 'instant' breakfast meeting / podcast with a scientist observer trying to make sense of it late night in Busan. A lot known-stuff, a lot 'unknown/perhaps unknowable'. As you say the universe computes onward!
Nate may not have been joking when he suggested American CEOs & billionaires will not be happy with testosterone loss. There is a flag in his mind also about measurable amount of plastic in the brain. Perhaps turning to the widespread use of mechanised intelligence and automation comes from an intuitive reaction? (I'm only semi-joking.)
The big one for me is that it is almost certain that fertility decline and health decline because of pollution is not just for humans but almost certainly happening across the creature world and the food chains. As the lady scientist said to Nate: 'plastics are not inert'.
Looks highly likely pollution will beat climate change to the punch?
Meanwhile America seems to have decided it is going to make a fight for its empire... so history conspires?
Interesting science and complexity... I have not checked for latest reviews? Creature world? Experiments?
Makes me think of levels easily above 800ppm in moderately crowded rooms and motor cars... the inexpensive monitors tell us it is not just 'after lunch'... modern times indeed!
Population will collapse because of a lack of affordable energy ... this will cause a collapse of the financial system ... followed by a vapourization of the global supply chains.
8+ B will be left to starve... they will murder rape and eat each other
My state is predicted to have 12% less elementary school children in 10 years. I tell my corporate bosses this to prepare for less, and the look at me with uncomprehending cow eyes.
In 2021 I published a paper that predicted population would peak right about now. It used systems dynamics, much like the work of Meadows et al in "Limits to Growth". The reasons for decline were rooted in global limits, not pollution or electromagnetic radiation or any of these explanations being put forth. It is very simple. Human population is limited by the food supply, and the food supply is peaking. Agricultural production can't get more efficient, there's no new arable land to be found, and fresh water resources are being used up faster than we find new ones. So it's food. The rest is "mechanism", meaning "How is the lack of food translated into fewer people?" Malthus teaches us that there are many ways, not just famine. I see the current worldwide decline in fertility as a sign that the cause is global, not local. So it's not pollution, not sperm counts, not education, and not availability of contraception. The best explanation is the global free availability of information, and the global economy. It means that resources flow towards money, and the availabilty of resources determines their cost to the consumer. Women interviewed by Guttmacher say thay are chosing smaller families, because the cost of raising a child is going up, and because the future looks bleak. My daughter has resolved to live "child free" because "how could I bring a child into this world at this time?" I think women do this calculus everywhere, prices are going up everywhere, and the sad state of the world (i.e. the climate) is known everywhere. Therefore fertility is dropping everywere. I predict that the 2030 census will show a decline for the first time in 700 years.
Hi Chris, nice to hear from you! I know your work, and an earlier version of this post had an illustration from your 2021 paper. Then, I removed it to keep the post short, but I am still planning to publish a post on your paper as soon as I can. Very interesting work. Did you publish anything on the same subject afterward?
No I have not published a follow-up because, I am actually a biochemist! I am behind in paper writing in that field. Next population paper will combine a climate model and population model. The model is done, but I need to analyze.
Thanks for this detailed analysis about an issue we've only hinted at a while ago.
It's quite convincing and surely chemical pollution must play a role (as sperm counts show at the very least).
And still, it doesn't explain so much why so many people seems quite happy with the small number of children they have. And take all the necessary mesures not to have more.
Unless of course, this attitude is chemically-induced too. But if so, it still raise the question why it's this way and not the other way around.
Hans Selye's General Adaptation Syndrome (GAS) applies to the negative impact of stress on fertility. Reg Morrison, Australian author and photojournalist, wrote about this in _The Spirit in the Gene_ 1/4 C ago. (foreword by Lynn Margulis, microbiologist and co-developer of Gaia Theory) Around 80% into this short course (written by Morrison) is "Evolution's Automatic Plague Limiter" (GAS). http://www.zo.utexas.edu/courses/THOC/gambler.pdf
The collapse is equivalent to "old age", not a real disease but something like the result of a complete development of a system: anything is bound to fail but seems immortal during the growth phase, any damage is mitigated by growth, seems stable in steady state, damage accumulate but is minor compared to the whole, but seems to collapse suddenly because the real extent of accumulated damage is acting as cascade. The end is begun at the end of growth...
Usually, the collapse is also the beginning of a new "life" for a different system, but today we are looking at a new situation because we have a growth that is global and total. The fall of a complex system was parallel to the growth of another one locally far and isolated, but today we didn't have anything that is complex enough and isolated, so we need a new something coming from INSIDE the failing system.
I suppose the next step is similar to the eukaryotic evolution, we had a long run of competing systems and need a step to begin the integrating phase, we had a try in industrial economy but degenerated toward competing. We have cellular economies competing but must learn to become organs then organism.
hi ugo how long do you see the population growing because you say the more people the more pollution so is bau scenario now off the table and do we move now to the bau 2 graph ?
In 2021 I published a paper that predicted population would peak right about now. It used systems dynamics, much like the work of Meadows et al in "Limits to Growth". The reasons for decline were rooted in global limits, not pollution or electromagnetic radiation or any of these explanations being put forth. It is very simple. Human population is limited by the food supply, and the food supply is peaking. Agricultural production can't get more efficient, there's no new arable land to be found, and fresh water resources are being used up faster than we find new ones. So it's food. The rest is "mechanism", meaning "How is the lack of food translated into fewer people?" Malthus teaches us that there are many ways, not just famine. I see the current worldwide decline in fertility as a sign that the cause is global, not local. So it's not pollution, not sperm counts, not education, and not availability of contraception. The best explanation is the global free availability of information, and the global economy. It means that resources flow towards money, and the availabilty of resources determines their cost to the consumer. Women interviewed by Guttmacher say thay are chosing smaller families, because the cost of raising a child is going up, and because the future looks bleak. My daughter has resolved to live "child free" because "how could I bring a child into this world at this time?" I think women do this calculus everywhere, prices are going up everywhere, and the sad state of the world (i.e. the climate) is known everywhere. Therefore fertility is dropping everywere. I predict that the 2030 census will show a decline for the first time in 700 years.
Today I had some time and I decided to learn a little bit of python and play with the maths on this post.
I started with a classic lokta-volterra I found already coded and I changed the differential equations.
I must say that the “Seneca model” doesn´t look very convincing to me. I understand that it’s just an intellectual exercise, but still. I cannot see the point.
I’m fine with the first equation, which is the same as Hubbert’s.
The second looks interesting to me too, with births being like in Hubbert’s and deaths rate multiplied by pollution. Why not?
The term -k5W looks fine to me too. By this implying some kind of gaia processing pollution. Or pollution having a predefined lifetime before it disappears. It’s optimistic, but for simplicity sake it looks ok.
The problem to me is with this k4PW term. I don’t see how pollution would reproduce itself with population. So instead, playing with the models, I changed it by k4PR. By this meaning that humans generate, each, as much pollution as we have remaining resources.
Models are always representations of what the modeler has in mind. The world may well be different. However, the K4PW term seems to me correct: it means that pollution is generated by population. More population, more pollution. And, yes, Gaia does reabsorb human-generated pollution -- slowly. The Hubbert model remains a staple one, but in the real world the curve is almost never symmetric
Sure, I'm just playing with the models for fun, understanding that the real world is far too complex for us to model reliably.
But still with the K4PW term, I don't think it should be multiplied per W. It is clear, as you say, that more population ==> more pollution increase. What is not clear to me is that more pollution ==> more pollution increase. Humans create pollution from scratch (from resources available), it's not humans helping pollution reproduce (in my mind).
Unless you do the exercise the other way around. You assume Seneca because of experience. You force a model to fit it. Then you try to make sense of it as, at least, this model fits what complex systems use to do. In my opinion this would be a fair exercise too. In this case, W increasing with W could mean some tipping point unleashing a Gaia problem that creates pollution, or that dampens its reabsorption. Although under this hypothesis we wouldn't need to multiply it per P anymore. Maybe a little too linear for a tipping point, but a sacrifice we do to ease the model. I’m letting the mind fly a little too far, so I stop here.
In any case, thank-you for the work and responses. It brings valuable thinking. And in this case, it’s been a nice playground to introduce me to python and coupled differential equations modelling.
I will be so bold as to attribute the decline in fertility to SPIRITUAL FACTORS, not foreseen as such in systems analysis. The BAU graph has been tracking well, and I think we had peak oil-plus-condensates in late 2018, along with peak CO2 output and peak industrial economy, but "we" are at a bumpy top, perhaps.
The biggest single factor in female fertility in our modern world is the assessments and intentions of fertile women.
There is a dread.
This is a mass-spiritual-entity of humanity, and of the life upon Gaia, I think.
I can't prove this, but I keep seeing it.
Likewise, it can't be "disproven" by those who just don't believe in "transpersonal" forms of consciousness.
The "dread" certainly exists among young Western women now. Perhaps it's already old news in the East.
Women can ( for probably the first time in history) reliably control their birth rate and they are feeling a real dread of bringing more children into an increasingly harsh world. True.
But biology matters as well. There are crashing fertility rates among many animals as well as among people.
it is also jorgen randers view he stated this on a news article on usbek rica it is also available on the club of rome website he stated it was more likely a pollution collapse than a resource collapse
hi professor ugo bardi why do you say in can take decades before we see an evident population collapse and chris bystroff states we will see a population decline in the 2030 census ?
You are talking about chemical pollution (which may indeed play a role), but there are plenty of other kinds of pollution. Light pollution and sound pollution come to mind. Might constant noise and a lack of night darkness make people less interested in sex and child raising? And then there's the issue of overcrowding. I have long suspected that the fertility collapse that we are observing is caused to quite a significant extent by our mammalian instinct against overcrowding. It would go a long way toward explaining why fertility is cratering all over the world, despite major differences in culture. Because all those cultures have one thing in common: urbanization and (therefore) overcrowding inherent in city living.
That could be, too. A good point.
"And then there's the issue of overcrowding."
Brings up the rat studies… https://www.newyorker.com/magazine/2024/10/07/dr-calhouns-mousery-lee-alan-dugatkin-book-reviews-rat-city-edmund-ramsden-and-jon-adams
I also wonder about electro-magnetic radiation. It's been just over 100 year since the first radio broadcast. Now we are constantly bombarded by all sorts of signals. Radio and TV, cell phone, routers, electricity, lighting - and these are just local. From space we are bombarded by various communications and imaging satellites that broadcast in a broad range of spectrums.
There are theories that all this electro-magnetic pollution is what causes migratory birds to fly off course, or the increase in erratic behaviour of large sea mammals, including large beachings. So what could it be doing to us?
Actually, where contraception means are available, it will always interfere with the whole picture as people can much more easily choose not to have children while still having sex as much as they like.
So it would be interesting to look at the trend in areas where contraception is not that common (either for social or cultural reason). Because if the number of children in falling there too, that would mean that either sexual activity or biological fertility are decreasing. If not both.
Beside, at a deep level, overcrowding might play a role on human psychology and behavior. But it might well be a mere corellation. What is the main reason is just wealth? Wealth give access to contraception. But more to the point, children don't generate wealth anymore while they cost and prevent one to fully enjoy wealth.
And then, education, pollution, urbanisation, etc just happen to come with wealth too.
I am not sure there are any *urban* areas anymore in which contraception is not readily available. Maybe some war zones, but wars don't tend to produce baby booms, do they?
Anyway, I'm sure that contraception plays *some* role, but still, why is it that people are suddenly so enthusiastic to use it? I mean, intellectuals used to panic about humans breeding like rabbits and refusing to use readily available contraception. So, what changed? The other thing is that, in the West, people are indeed having less sex than they used to (or at least that's what social scientists keep telling us). And East Asia is kind of like the West, only more so.
I guess it could be possible to study densely populated areas where religion tend to forbid contraception. Then compare with places were traditions or religion is less prevalent. And places where people tend to be richer or poorer. Or more or less polluted.
That's the thing... there are a lot of factors.
What religion forbids contraception? Well, there are the Orthodox Jews, for example, but the thing with such religions is that they have a large "defection" rate. People grow up in the religion and then leave if they don't like it. Those who stay are a self-selected sample. If you want an entire *area* (so, you're not focusing on some subpopulation that can be defected from relatively easily), I'm not sure you're going to find it. At least not in urban areas. Well, maybe in Africa. But that's the thing: fertility is falling in Africa, too. Sure, it's above replacement - for now. Well, Korean women had something like 6 children per woman just a couple of generations ago.
My guess is that, fundamentally, it's urbanization. Cities have never been able to reproduce themselves, and they only ever managed to grow due to immigration (from rural areas). The details will vary, but if you cram people into cities, they do not produce enough babies to reproduce themselves. (Of course, replacement rate depends on child mortality, which used to be very high in cities.) If you took away contraception - well, take a look at how that worked out in Romania. Initially, they had a massive baby boom, but then birth rates very quickly started declining again, despite contraception remaining illegal. And of course, Romania became world-famous due to its orphanages...
Actually, I agree with you that urbanization plays a role.
But is it because of some kind of deep unconscious ingrained mammalian mechanism destined to avoid overpopulation ? or because of much more conscious choices linked to very straightforward economic reasons ? or because of a decrease of fertility or even sexual activity due to high level of pollution ?
In other words, before contraception (that is before people could really make choices) and/or before chemical pollution, does urban women give birth to less children than rural ones ? I wonder... Maybe.
"In other words, before contraception (that is before people could really make choices) and/or before chemical pollution, does urban women give birth to less children than rural ones ?"
Good question. Data doubtless exists (at least for Western Europe for the past few centuries), but I'm not familiar with it. Certainly, infant mortality was higher in cities, but I simply don't know about fertility rates. If fertility rates were indeed lower for urban women, that would be evidence for my overcrowding hypothesis.
As for wealth: wealthy peasants have more children than poor ones do, right? So again, urbanization.
I'm not so sure...
Wealth or poverty generated by having a large number of children is a complicated matter.
It is easy to imagine how it could be difficult to feed a lot of children. An the issues that may arise when dividing between them the piece of land or the small business that provide just enough for the family.
But on the other hand, when there is no social benefits, medicare or retirement plans, children are the only form of insurance available. So even if it might cost a lot, the sensible thing is to have at least half a dozen, given the fact that a good share of them can die along the way and it's always possible to send some to the army or to the church.
Of course, none of this logic still fully apply in the modern world when society is getting wealthy enough to offer social benefits.
Yes, and the creature world. I had no idea of the importance of light patterns as they change day/night for the creature world until I read this research paper. I wrote this back in the summer as an update on a book review.
"More concerning in my mind is the subtle effect on the scattering of celestial light patterns which regulate behaviour in many species of animals, especially perhaps many insects. I have seen nothing yet on how this is going. See my Reference 4. below, scroll down after my extensive section of footnotes; this is the study referred to: https://bit.ly/45ikDfs" PS The intro gives the gist.
https://en.wikipedia.org/wiki/Behavioral_sink
I suppose this can be related, our situation is not so extreme as the total collapse, but interesting because society seems to fall before resources viability affect it.
I usually use that experiment in discussions, I suppose it is not only overcrowd because rats are quite used to really overcrowd situations and paradoxically thrive most in overcrowd and scarce resources conditions, so I find it one of the most intriguing experiments.
I feel like the triggering event is when the survival of the single is no more linked to the colony, cooperation didn't is more the most useful move so a lot of derived habits are erased and rats have a lot of them: they are quite found to get sacrificial individual for exploring new areas, usually the weak ones (not coerced), too old ones in the colony go to feed first on new or strange foods for test them if really eatable, male defend children of any female of the colony and female feed orphaned, they also have some form of tending of the sick...
Broken the link between individual survival and colony unneeded cannibalism also happened in the experiment, stray impulses unlinked and untamed make this too possible!
Statistical data shows that last year of population growth in Serbia was 1991 (0,2%). From that year there is steady decline which is accelerating. Currently Serbia loses between 40 and 50 thousand people per year, a colossal decline for a country of 6,5 mil. I think that in Serbia's case Seneca cliff is proven fact.
I think Taiwan is worse
Right on the button with the failure / postponement of the preparation for a plastics treaty. Nate Hagens has just done a Great Simplification 'instant' breakfast meeting / podcast with a scientist observer trying to make sense of it late night in Busan. A lot known-stuff, a lot 'unknown/perhaps unknowable'. As you say the universe computes onward!
Nate may not have been joking when he suggested American CEOs & billionaires will not be happy with testosterone loss. There is a flag in his mind also about measurable amount of plastic in the brain. Perhaps turning to the widespread use of mechanised intelligence and automation comes from an intuitive reaction? (I'm only semi-joking.)
The big one for me is that it is almost certain that fertility decline and health decline because of pollution is not just for humans but almost certainly happening across the creature world and the food chains. As the lady scientist said to Nate: 'plastics are not inert'.
Looks highly likely pollution will beat climate change to the punch?
Meanwhile America seems to have decided it is going to make a fight for its empire... so history conspires?
CO2 is not inert either. Once the elites start realizing this point, some things may change. But it is not clear how and how much.
Interesting science and complexity... I have not checked for latest reviews? Creature world? Experiments?
Makes me think of levels easily above 800ppm in moderately crowded rooms and motor cars... the inexpensive monitors tell us it is not just 'after lunch'... modern times indeed!
Population will collapse because of a lack of affordable energy ... this will cause a collapse of the financial system ... followed by a vapourization of the global supply chains.
8+ B will be left to starve... they will murder rape and eat each other
This CANNOT be allowed to happen hence this https://fasteddynz.substack.com/p/the-ultimate-extinction-plan-uep
"Oh no, the CO2 level went from less than one in a thousand parts to still less than one in a thousand parts" ... these people are not reachable.
Usual legends. I suppose it gives you some solace repeating it, but it won't make much of a difference.
My state is predicted to have 12% less elementary school children in 10 years. I tell my corporate bosses this to prepare for less, and the look at me with uncomprehending cow eyes.
In 2021 I published a paper that predicted population would peak right about now. It used systems dynamics, much like the work of Meadows et al in "Limits to Growth". The reasons for decline were rooted in global limits, not pollution or electromagnetic radiation or any of these explanations being put forth. It is very simple. Human population is limited by the food supply, and the food supply is peaking. Agricultural production can't get more efficient, there's no new arable land to be found, and fresh water resources are being used up faster than we find new ones. So it's food. The rest is "mechanism", meaning "How is the lack of food translated into fewer people?" Malthus teaches us that there are many ways, not just famine. I see the current worldwide decline in fertility as a sign that the cause is global, not local. So it's not pollution, not sperm counts, not education, and not availability of contraception. The best explanation is the global free availability of information, and the global economy. It means that resources flow towards money, and the availabilty of resources determines their cost to the consumer. Women interviewed by Guttmacher say thay are chosing smaller families, because the cost of raising a child is going up, and because the future looks bleak. My daughter has resolved to live "child free" because "how could I bring a child into this world at this time?" I think women do this calculus everywhere, prices are going up everywhere, and the sad state of the world (i.e. the climate) is known everywhere. Therefore fertility is dropping everywere. I predict that the 2030 census will show a decline for the first time in 700 years.
If you are interested in reading the paper, here is the link https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0247214
Hi Chris, nice to hear from you! I know your work, and an earlier version of this post had an illustration from your 2021 paper. Then, I removed it to keep the post short, but I am still planning to publish a post on your paper as soon as I can. Very interesting work. Did you publish anything on the same subject afterward?
No I have not published a follow-up because, I am actually a biochemist! I am behind in paper writing in that field. Next population paper will combine a climate model and population model. The model is done, but I need to analyze.
In this field, we are all moonlighting. I do the same with my models. I am looking forward to your new paper!
new paper about why food production is not peaking but stable https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0313088
Thanks for this detailed analysis about an issue we've only hinted at a while ago.
It's quite convincing and surely chemical pollution must play a role (as sperm counts show at the very least).
And still, it doesn't explain so much why so many people seems quite happy with the small number of children they have. And take all the necessary mesures not to have more.
Unless of course, this attitude is chemically-induced too. But if so, it still raise the question why it's this way and not the other way around.
Hans Selye's General Adaptation Syndrome (GAS) applies to the negative impact of stress on fertility. Reg Morrison, Australian author and photojournalist, wrote about this in _The Spirit in the Gene_ 1/4 C ago. (foreword by Lynn Margulis, microbiologist and co-developer of Gaia Theory) Around 80% into this short course (written by Morrison) is "Evolution's Automatic Plague Limiter" (GAS). http://www.zo.utexas.edu/courses/THOC/gambler.pdf
The collapse is equivalent to "old age", not a real disease but something like the result of a complete development of a system: anything is bound to fail but seems immortal during the growth phase, any damage is mitigated by growth, seems stable in steady state, damage accumulate but is minor compared to the whole, but seems to collapse suddenly because the real extent of accumulated damage is acting as cascade. The end is begun at the end of growth...
Usually, the collapse is also the beginning of a new "life" for a different system, but today we are looking at a new situation because we have a growth that is global and total. The fall of a complex system was parallel to the growth of another one locally far and isolated, but today we didn't have anything that is complex enough and isolated, so we need a new something coming from INSIDE the failing system.
I suppose the next step is similar to the eukaryotic evolution, we had a long run of competing systems and need a step to begin the integrating phase, we had a try in industrial economy but degenerated toward competing. We have cellular economies competing but must learn to become organs then organism.
hi ugo how long do you see the population growing because you say the more people the more pollution so is bau scenario now off the table and do we move now to the bau 2 graph ?
will we collapse in 2025 according to the limits to growth we will reach peak food production ?
In 2021 I published a paper that predicted population would peak right about now. It used systems dynamics, much like the work of Meadows et al in "Limits to Growth". The reasons for decline were rooted in global limits, not pollution or electromagnetic radiation or any of these explanations being put forth. It is very simple. Human population is limited by the food supply, and the food supply is peaking. Agricultural production can't get more efficient, there's no new arable land to be found, and fresh water resources are being used up faster than we find new ones. So it's food. The rest is "mechanism", meaning "How is the lack of food translated into fewer people?" Malthus teaches us that there are many ways, not just famine. I see the current worldwide decline in fertility as a sign that the cause is global, not local. So it's not pollution, not sperm counts, not education, and not availability of contraception. The best explanation is the global free availability of information, and the global economy. It means that resources flow towards money, and the availabilty of resources determines their cost to the consumer. Women interviewed by Guttmacher say thay are chosing smaller families, because the cost of raising a child is going up, and because the future looks bleak. My daughter has resolved to live "child free" because "how could I bring a child into this world at this time?" I think women do this calculus everywhere, prices are going up everywhere, and the sad state of the world (i.e. the climate) is known everywhere. Therefore fertility is dropping everywere. I predict that the 2030 census will show a decline for the first time in 700 years.
Today I had some time and I decided to learn a little bit of python and play with the maths on this post.
I started with a classic lokta-volterra I found already coded and I changed the differential equations.
I must say that the “Seneca model” doesn´t look very convincing to me. I understand that it’s just an intellectual exercise, but still. I cannot see the point.
I’m fine with the first equation, which is the same as Hubbert’s.
The second looks interesting to me too, with births being like in Hubbert’s and deaths rate multiplied by pollution. Why not?
The term -k5W looks fine to me too. By this implying some kind of gaia processing pollution. Or pollution having a predefined lifetime before it disappears. It’s optimistic, but for simplicity sake it looks ok.
The problem to me is with this k4PW term. I don’t see how pollution would reproduce itself with population. So instead, playing with the models, I changed it by k4PR. By this meaning that humans generate, each, as much pollution as we have remaining resources.
The result doesn’t look Seneca anymore.
Models are always representations of what the modeler has in mind. The world may well be different. However, the K4PW term seems to me correct: it means that pollution is generated by population. More population, more pollution. And, yes, Gaia does reabsorb human-generated pollution -- slowly. The Hubbert model remains a staple one, but in the real world the curve is almost never symmetric
does that mean there won't be a senneca collapse anymore ?
No, it just means that I was playing with the model and I found details to discuss.
Sure, I'm just playing with the models for fun, understanding that the real world is far too complex for us to model reliably.
But still with the K4PW term, I don't think it should be multiplied per W. It is clear, as you say, that more population ==> more pollution increase. What is not clear to me is that more pollution ==> more pollution increase. Humans create pollution from scratch (from resources available), it's not humans helping pollution reproduce (in my mind).
Unless you do the exercise the other way around. You assume Seneca because of experience. You force a model to fit it. Then you try to make sense of it as, at least, this model fits what complex systems use to do. In my opinion this would be a fair exercise too. In this case, W increasing with W could mean some tipping point unleashing a Gaia problem that creates pollution, or that dampens its reabsorption. Although under this hypothesis we wouldn't need to multiply it per P anymore. Maybe a little too linear for a tipping point, but a sacrifice we do to ease the model. I’m letting the mind fly a little too far, so I stop here.
In any case, thank-you for the work and responses. It brings valuable thinking. And in this case, it’s been a nice playground to introduce me to python and coupled differential equations modelling.
Thank You, Ugo.
I will be so bold as to attribute the decline in fertility to SPIRITUAL FACTORS, not foreseen as such in systems analysis. The BAU graph has been tracking well, and I think we had peak oil-plus-condensates in late 2018, along with peak CO2 output and peak industrial economy, but "we" are at a bumpy top, perhaps.
The biggest single factor in female fertility in our modern world is the assessments and intentions of fertile women.
There is a dread.
This is a mass-spiritual-entity of humanity, and of the life upon Gaia, I think.
I can't prove this, but I keep seeing it.
Likewise, it can't be "disproven" by those who just don't believe in "transpersonal" forms of consciousness.
The "dread" certainly exists among young Western women now. Perhaps it's already old news in the East.
Women can ( for probably the first time in history) reliably control their birth rate and they are feeling a real dread of bringing more children into an increasingly harsh world. True.
But biology matters as well. There are crashing fertility rates among many animals as well as among people.
i do not understand it do we face population collapse now or in a few decades ?
No rush!
thank you ugo for your response may i ask what did change your mind exactly from resource collapse to pollution collapse ?
When I have new data, I change my mind (attributed to Lord Keynes)
it is also jorgen randers view he stated this on a news article on usbek rica it is also available on the club of rome website he stated it was more likely a pollution collapse than a resource collapse
so the data is bau 2 collapse may happen in 2040 just like Michael dowd said to ugo bardi in an interview on youtube ?
hi professor ugo bardi why do you say in can take decades before we see an evident population collapse and chris bystroff states we will see a population decline in the 2030 census ?
Faster will be worser. War, pestilence, famine, etc.
Just a link to a timely CNN article on aging populations
https://www.cnn.com/2024/12/24/asia/south-korea-super-aged-society-intl-hnk/index.html