Decline in total human population is the elephant in the room that no one talks about. Perhaps an unspoken fear that is behind current political upheavals? Early twitching in
a radical re-orientation between the sexes/ genders and a much needed decrease in consumption. Which our Earth might thank us for. Or maybe she is behind the whole thing g after all?!!
Thanks Ugo. A lot of young people, with good jobs and marriages, see the world of the near future as a bad place for children, and think they should not do that, not bring children into it.
I feel that without western vaccines, disease outbreak intervention, and birth control -as well as incredible amounts of imported food-the population of Africa will limit itself in the most tragic way.
Any useful academic work will need to respond to critique in the iterative process prior to publication, and in this regard, I offer some considerations to prof. Ugo Bardi, that may provide useful revisions regarding his next book.
Of course, one can endlessly speculate as to how the process of collapse will unfold for different people in different places. However, even when factoring in multiple variables as does the Limits To Growth modeling, a number of variables are inevitably not accounted for, such as nuclear weapons exchanges, geoengineering successes and failures, and other various 'unknown unknowns'. Ultimately, the complex interaction of a multitude of complex systems lends itself much better to scenario planning, as the original Limits To Growth team provided, than it does to prognostication.
Furthermore, it is absolutely vital when considering global and national human fertility projections, to recognise the science and data which demonstrates - that accelerating global decline of viable sperm at its current trajectory implies human births in the second half of the century will be miraculous. The robust international data accrued by the research team has been published in various Tier 1 academic journals, titled - "Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries".
I politely suggest that this research requires a general reworking of the premises which underpin the book's proposal.
Overshoot is a concept embedded in many fields, from economics to the biology of populations. It is the fundamental element of the Seneca Effect. One of those simple and powerful concepts that explain many things. It is, in the end, a dynamic consequence of the thermodynamic dissipation of energy potential. The way the universe works.
Impending global population decline may be the most significant fact in our world. It is ironically the least recognized and least discussed important fact. I imagine I see 100 mentions of microplastics for every mention of global population decline.
Traditionally population decline is seen as some kind of dire eventuality. I see it as a salvation of the Earth. I expect global decline to begin around 2050, mid-century.
I estimate that a global population between 500 million and 800 million is sustainable long-term, meaning there is no cumulative damage to nature over time. At that population level Nature can repair the negative effects of human presence as fast as they occur. Of course what we have right now with 8.2 billion humans means rapid destruction of nature.
I see a 90% reduction in human population as the ultimate panacea: it fixes everything. No need to argue about retired turbine blades!
You say population decline is inevitable, and I agree, but it is not irreversible. An Earth with less than a billion humans would be a perpetual paradise, combining an abundance of nature with the blessings of technology. Gaia would be smiling. On such an Earth people could confidently increase their birthright to a stable rate, e.g. average fertility of 2.1.
Ugo, let's have a debate and publish it in your book.
I claim that a global fertility rate equivalent to Italy's will drop the human population of Earth below 1 billion within 200 years and save the Earth. Apparently you don't see a salvation. So let's thrash it out: write the best debate we can put on paper calling on the most informed resources.
This is the most important discussion in the world right now, and would make fascinating reading.
I take that as a "No". No, you will not debate my assertion that we are not doomed. Note, that I am not asking you to change anything you are saying. Only to take me seriously, listen to my arguments, and counter with your own.
You are certainly the expert on what your book needs and doesn't need. So let's consider the debate idea separately.
Imagine 1000 typical well-infomed humans. 990 of them have never seriously considered the possibility that humans might not survive the next few centuries. 9 of them are convinced that humans will not survive the next few decades. One of the thousand is saying: Yes, we can survive, if we do the right thing (which is mostly reduce population).
The 990 are not motivating anyone. The 9 are simply depressing everyone. We need to hear from the one.
To me the situation is perfectly clear: we need to get the population down relatively quickly without killing people, and we have some time to do this. Moreover fertility is falling rapidly. The trend we need is already in place; we just need to encourage it.
And and yet almost no one agrees with me. That blows my mind. The 990 don't see a problem. The 9 think there is no hope. Blows my mind.
I'm proposing an excellent, clarifying, well-sourced debate. Make your case that collapse is inevitable. (I'm not sure you believe this, but you haven't said otherwise.) I'll make my case that we could stop population growth in 10 years if we tried with just free contraceptives and subsidies.
In 100 years world population could be 5 billion. In 200 years, 800 million. Ecological recovery would begin rapidly.
Yes, I agree. I may be missing something fundamental, but I don't see many downsides to there being fewer of our species on this planet--especially given the way we over-exploit the planet's resources. FWIW, the World Population Clock shows that the global population has grown by well over 19 million just in the first 3+ months of this year (https://www.worldometers.info/world-population/)
There is no question in my mind that we are well into overshoot. I say the delta between what is sustainable and what we have is at least 7 billion people. So the only outstanding question is how long before collapse. If collapse occurs in this century then we are doomed. By the way, when I say collapse, I mean no electrical grid. I predict a surviving human population of a few million. This would certainly include uncontacted and rarely contacted indigenous tribes. It might also include some high-tech bubbles around hydroelectric plants. Any place within human civilization would have to be very well defended against the billion or so starving humans that would want what they had. That period would last for about 3 months before most everyone else was dead.
The only potential downside I can see is the need for continued technological advancement. I think that need can easily be met with a population of 1 billion humans and quite possibly with a significantly smaller population.
As part of the Club of Rome's Earth4All, we modellers did an in-depth, regional analysis of global population to 2100; building of course on LTG, but having much more granular (200) cohorts; Check it out: https://earth4all.life/views/the-population-boon/
>> If resources were distributed more fairly, today’s global population would already enjoy living conditions exceeding the UN’s minimum level, and without the need for significant changes in developmental trends.<<
Ethically, this must be supported, but won't this mean that total consumption will rise? Won't this destroy the biosphere even faster?
A middle-class American May consume as much as 100 African villagers, but if you take those 100 villagers and make them lower-middle-class, or even lower class, I think it is inevitable that total consumption would rise.
The only approach that I can see that is ethically sound and saves the biosphere is steady population decline to under 1 billion humans over 200 years through birth control.
so professor jorgen randers was also partly right then older people dying because of aging and young people becoming more career focused and richer so fewer childeren he saw population peaking around 2040 ?
hi 👋 professor ugo what does this mean population will decline not with a bang but with a whimper if I translate whimper it means in dutch the hair on my eyelid ?
FWIW across a breeding population, a 2% decline in population per annum and the population is half in roughly 35 years. The same for births, half the number of births if that is what is steadily / gradually declining. There are factors could speed things up. Bulgaria; if the breeding young depart for elsewhere, the remaining population can lose numbers very quickly.
Perhaps worth reexamining rapid urbanisation in England 17thC to 19thC. Huge child death rates but a time of doubling, and doubling again the total population, well beyond earlier 'carrying capacity'. (There is an Australian theorist - sorry forget the name - who conjectures high infant death rate has been a biological / social driver in the human response of 'overshoot' births.) Yes, the new urban populations of England got fed, but in 19thC only just.
-> https://www.youtube.com/watch?v=Ufmu1WD2TSk (published 12 days, and 10M views, "South Korea is over", check the comments, so many younger Korean well aware of the issue and the future waiting for them :-(
Reg Morrison addressed this with reference to Hans Selye's GAS (General Adaptation Syndrome) 1/4 C ago, and foresaw a peak by mid century. Christopher Bystroff's 2021 paper sees 2030 as likely. See:
>>The discrepancies between the projected growth and the actual population data since 1970 are accounted for by a decrease in the global carrying capacity due to ecosystem degradation.<<
I believe "discrepancies" in this context refers to slower than expected population growth. And I understand "ecosystem degradation" to imply higher than expected death rates. An altewrnative explanation would be lower than expected birth rates. Does the data support higher death rates? Is this consistent with the known increase in global life expectancy?
Ecosystem degradation increases stresses on people, mainly unconsciously. It reduces fertility as well as increases sickness. Modern medicine has remediated much of the impact on longevity. Stats in the US, Russia, and other countries show declines in life expectancy. In underdeveloped countries, medicine including vaccines has been extending longevity. See 80% into this short course Evolution's Automatic Plague Limiter: http://www.zo.utexas.edu/courses/THOC/gambler.pdf
I'm not concerned with life extension. I'm concerned with destruction of the biosphere. As long as life extension is stable or rising, it means we have some time left to reduce human population and save Nature.
My main point is to question whether you can have rising death rates and increasing human longevity at the same time. This seems unlikely to me.
Life expectancy fell dramatically in the US during the Covid years and did not fall at all in the Dominican Republic (where I live now) during those same years. This is certainly curious.
Why is LE in the US worse than other first world countries?
>>The report found the life expectancy gap is due to the following:
Cardiovascular disease
Overdose deaths
Gun-related deaths
Motor vehicle crashes<<
None of these causes are associated with the ecology. The first is diet related (a disease of affluence), and the other three are sociological.
You mention Russia as another country with decreasing or stagnant life expectancy. This prompts the question: Is vigorous participation in the Cold War detrimental to health?
But worldwide life expectancy is increasing. Google AI says:
>>Global average life expectancy in 2024 is 73.33 years, according to the United Nations. This represents a slight increase from 2023, when it was 73.16 years. Life expectancy has been steadily increasing over the past few decades, with significant gains observed since the mid-1900s. <<
I find this to be incompatible with the assertion that ecosystem degradation is a significant factor in mortality AT THIS TIME. Note that I consider ecosystem destruction to be the greatest risk facing human beings in the future.
Decline in total human population is the elephant in the room that no one talks about. Perhaps an unspoken fear that is behind current political upheavals? Early twitching in
a radical re-orientation between the sexes/ genders and a much needed decrease in consumption. Which our Earth might thank us for. Or maybe she is behind the whole thing g after all?!!
Have you swapped GDPs for Russia and Japan in your list of country data, by any chance?
Could be. The table is still a preliminary version. Will check that. Thanks!
You were right. There was a mistake. Thanks for the alert!
Re: Ukraine
Didn't you mean .87%, not 8.7%?
Yes, that was a typo. Thanks!
Thanks Ugo. A lot of young people, with good jobs and marriages, see the world of the near future as a bad place for children, and think they should not do that, not bring children into it.
These are some of my children and their peers.
I feel that without western vaccines, disease outbreak intervention, and birth control -as well as incredible amounts of imported food-the population of Africa will limit itself in the most tragic way.
That seems like the most rational projection.
When you look at global population projections for this century, all of the projections assume a very large increase in population in Africa.
Hi Ugo
Wondering if you're familiar with the work of Christopher Bystroff, who modeled peak global population as occurring approximately in the present:
Citation: Bystroff C (2021) Footprints to
singularity: A global population model explains late 20th century slow-down and predicts peak
within ten years. PLoS ONE 16(5): e0247214. https://doi. org/10.1371/journal.pone.0247214
Editor: Eda Ustaoglu, Gebze Teknik Universitesi, TURKEY
Received: February 2, 2021
Yes. Chris has been commenting in this thread
Any useful academic work will need to respond to critique in the iterative process prior to publication, and in this regard, I offer some considerations to prof. Ugo Bardi, that may provide useful revisions regarding his next book.
Of course, one can endlessly speculate as to how the process of collapse will unfold for different people in different places. However, even when factoring in multiple variables as does the Limits To Growth modeling, a number of variables are inevitably not accounted for, such as nuclear weapons exchanges, geoengineering successes and failures, and other various 'unknown unknowns'. Ultimately, the complex interaction of a multitude of complex systems lends itself much better to scenario planning, as the original Limits To Growth team provided, than it does to prognostication.
Furthermore, it is absolutely vital when considering global and national human fertility projections, to recognise the science and data which demonstrates - that accelerating global decline of viable sperm at its current trajectory implies human births in the second half of the century will be miraculous. The robust international data accrued by the research team has been published in various Tier 1 academic journals, titled - "Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries".
I politely suggest that this research requires a general reworking of the premises which underpin the book's proposal.
Since I'm the one who first raised the issue of Overshoot, Dr. Bardi, I would be very interested in reading your thoughts about it. Grazie!
Overshoot is a fundamental concept discussed, examined, dissected, considered, analyzed, and more in the book!
Might you be willing to post a quick summary of your ideas on the topic? Again, Grazie!
Overshoot is a concept embedded in many fields, from economics to the biology of populations. It is the fundamental element of the Seneca Effect. One of those simple and powerful concepts that explain many things. It is, in the end, a dynamic consequence of the thermodynamic dissipation of energy potential. The way the universe works.
Impending global population decline may be the most significant fact in our world. It is ironically the least recognized and least discussed important fact. I imagine I see 100 mentions of microplastics for every mention of global population decline.
Traditionally population decline is seen as some kind of dire eventuality. I see it as a salvation of the Earth. I expect global decline to begin around 2050, mid-century.
Rodes.pub/OneBillion
I estimate that a global population between 500 million and 800 million is sustainable long-term, meaning there is no cumulative damage to nature over time. At that population level Nature can repair the negative effects of human presence as fast as they occur. Of course what we have right now with 8.2 billion humans means rapid destruction of nature.
I see a 90% reduction in human population as the ultimate panacea: it fixes everything. No need to argue about retired turbine blades!
You say population decline is inevitable, and I agree, but it is not irreversible. An Earth with less than a billion humans would be a perpetual paradise, combining an abundance of nature with the blessings of technology. Gaia would be smiling. On such an Earth people could confidently increase their birthright to a stable rate, e.g. average fertility of 2.1.
The problem is that between hell and paradise there is a steep Seneca cliff
Ugo, let's have a debate and publish it in your book.
I claim that a global fertility rate equivalent to Italy's will drop the human population of Earth below 1 billion within 200 years and save the Earth. Apparently you don't see a salvation. So let's thrash it out: write the best debate we can put on paper calling on the most informed resources.
This is the most important discussion in the world right now, and would make fascinating reading.
I am sure there will be a debate about this book. We will have it in several places -- it will be surely interesting!
I take that as a "No". No, you will not debate my assertion that we are not doomed. Note, that I am not asking you to change anything you are saying. Only to take me seriously, listen to my arguments, and counter with your own.
But thanks for the reply.
Peter, the book is already 70,000 words. If it has to be a book, it already long enough. Debates will be around the book, not in the books
You are certainly the expert on what your book needs and doesn't need. So let's consider the debate idea separately.
Imagine 1000 typical well-infomed humans. 990 of them have never seriously considered the possibility that humans might not survive the next few centuries. 9 of them are convinced that humans will not survive the next few decades. One of the thousand is saying: Yes, we can survive, if we do the right thing (which is mostly reduce population).
The 990 are not motivating anyone. The 9 are simply depressing everyone. We need to hear from the one.
To me the situation is perfectly clear: we need to get the population down relatively quickly without killing people, and we have some time to do this. Moreover fertility is falling rapidly. The trend we need is already in place; we just need to encourage it.
And and yet almost no one agrees with me. That blows my mind. The 990 don't see a problem. The 9 think there is no hope. Blows my mind.
I'm proposing an excellent, clarifying, well-sourced debate. Make your case that collapse is inevitable. (I'm not sure you believe this, but you haven't said otherwise.) I'll make my case that we could stop population growth in 10 years if we tried with just free contraceptives and subsidies.
In 100 years world population could be 5 billion. In 200 years, 800 million. Ecological recovery would begin rapidly.
Let's do this.
Yes, I agree. I may be missing something fundamental, but I don't see many downsides to there being fewer of our species on this planet--especially given the way we over-exploit the planet's resources. FWIW, the World Population Clock shows that the global population has grown by well over 19 million just in the first 3+ months of this year (https://www.worldometers.info/world-population/)
As far as I can tell, Ecological Overshoot (see William Catton's 1980 book "Overshoot" and many subsequent online discussions. Here's the wikipedia article for a starter: https://en.wikipedia.org/wiki/Overshoot_(population)?ref=collapsemusings.com&useskin=vector) is pretty darned hard to refute.
Catton's book made a fundamental contribution to my own world view.
There is no question in my mind that we are well into overshoot. I say the delta between what is sustainable and what we have is at least 7 billion people. So the only outstanding question is how long before collapse. If collapse occurs in this century then we are doomed. By the way, when I say collapse, I mean no electrical grid. I predict a surviving human population of a few million. This would certainly include uncontacted and rarely contacted indigenous tribes. It might also include some high-tech bubbles around hydroelectric plants. Any place within human civilization would have to be very well defended against the billion or so starving humans that would want what they had. That period would last for about 3 months before most everyone else was dead.
The only potential downside I can see is the need for continued technological advancement. I think that need can easily be met with a population of 1 billion humans and quite possibly with a significantly smaller population.
As part of the Club of Rome's Earth4All, we modellers did an in-depth, regional analysis of global population to 2100; building of course on LTG, but having much more granular (200) cohorts; Check it out: https://earth4all.life/views/the-population-boon/
Yes, your work is cited in the book!
>> If resources were distributed more fairly, today’s global population would already enjoy living conditions exceeding the UN’s minimum level, and without the need for significant changes in developmental trends.<<
Ethically, this must be supported, but won't this mean that total consumption will rise? Won't this destroy the biosphere even faster?
A middle-class American May consume as much as 100 African villagers, but if you take those 100 villagers and make them lower-middle-class, or even lower class, I think it is inevitable that total consumption would rise.
The only approach that I can see that is ethically sound and saves the biosphere is steady population decline to under 1 billion humans over 200 years through birth control.
so it is fewer birth's and older people dying of old age than ?
It is.
thank you very much ugo does that mean the big seneca collapse will not come the resource or climate collapse ?
Nobody knows. Pray Gaia and go forward.
so professor jorgen randers was also partly right then older people dying because of aging and young people becoming more career focused and richer so fewer childeren he saw population peaking around 2040 ?
hi 👋 professor ugo what does this mean population will decline not with a bang but with a whimper if I translate whimper it means in dutch the hair on my eyelid ?
Lifeexpectancy will flatten out. Its difficult to extend life expectancy.https://www.nature.com/articles/s43587-024-00702-3
It will be a long time before near 8 billion contracts back to sustainable levels of 2 billion max or less.
Or not. Depends how sharp the inflection points.
FWIW across a breeding population, a 2% decline in population per annum and the population is half in roughly 35 years. The same for births, half the number of births if that is what is steadily / gradually declining. There are factors could speed things up. Bulgaria; if the breeding young depart for elsewhere, the remaining population can lose numbers very quickly.
Perhaps worth reexamining rapid urbanisation in England 17thC to 19thC. Huge child death rates but a time of doubling, and doubling again the total population, well beyond earlier 'carrying capacity'. (There is an Australian theorist - sorry forget the name - who conjectures high infant death rate has been a biological / social driver in the human response of 'overshoot' births.) Yes, the new urban populations of England got fed, but in 19thC only just.
Your new book is eagerly awaited, Ugo.
-> https://www.youtube.com/watch?v=Ufmu1WD2TSk (published 12 days, and 10M views, "South Korea is over", check the comments, so many younger Korean well aware of the issue and the future waiting for them :-(
Reg Morrison addressed this with reference to Hans Selye's GAS (General Adaptation Syndrome) 1/4 C ago, and foresaw a peak by mid century. Christopher Bystroff's 2021 paper sees 2030 as likely. See:
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0247214
I know Bystroff's work. It aligns more or less with other dynamic models. Peak population is supposed to arrive between 2030 and 2040
i predicted the peak would be most likely before 2030. i am working on a revision however, World4.6
typo: 2030, not 2013
Ops… thanks!
edited, so should be fixed
>>The discrepancies between the projected growth and the actual population data since 1970 are accounted for by a decrease in the global carrying capacity due to ecosystem degradation.<<
I believe "discrepancies" in this context refers to slower than expected population growth. And I understand "ecosystem degradation" to imply higher than expected death rates. An altewrnative explanation would be lower than expected birth rates. Does the data support higher death rates? Is this consistent with the known increase in global life expectancy?
Ecosystem degradation increases stresses on people, mainly unconsciously. It reduces fertility as well as increases sickness. Modern medicine has remediated much of the impact on longevity. Stats in the US, Russia, and other countries show declines in life expectancy. In underdeveloped countries, medicine including vaccines has been extending longevity. See 80% into this short course Evolution's Automatic Plague Limiter: http://www.zo.utexas.edu/courses/THOC/gambler.pdf
I'm not concerned with life extension. I'm concerned with destruction of the biosphere. As long as life extension is stable or rising, it means we have some time left to reduce human population and save Nature.
https://en.wikipedia.org/wiki/Planetary_boundaries
Thank you for your prompt reply!
My main point is to question whether you can have rising death rates and increasing human longevity at the same time. This seems unlikely to me.
Life expectancy fell dramatically in the US during the Covid years and did not fall at all in the Dominican Republic (where I live now) during those same years. This is certainly curious.
Why is LE in the US worse than other first world countries?
https://publichealth.jhu.edu/2024/new-report-life-expectancy-years-shorter-in-the-united-states-compared-to-the-united-kingdom
>>The report found the life expectancy gap is due to the following:
Cardiovascular disease
Overdose deaths
Gun-related deaths
Motor vehicle crashes<<
None of these causes are associated with the ecology. The first is diet related (a disease of affluence), and the other three are sociological.
You mention Russia as another country with decreasing or stagnant life expectancy. This prompts the question: Is vigorous participation in the Cold War detrimental to health?
But worldwide life expectancy is increasing. Google AI says:
>>Global average life expectancy in 2024 is 73.33 years, according to the United Nations. This represents a slight increase from 2023, when it was 73.16 years. Life expectancy has been steadily increasing over the past few decades, with significant gains observed since the mid-1900s. <<
I find this to be incompatible with the assertion that ecosystem degradation is a significant factor in mortality AT THIS TIME. Note that I consider ecosystem destruction to be the greatest risk facing human beings in the future.
Its economic, sosial and biological difficult to extend lifeexpectansy in western countries. https://www.nature.com/articles/s43587-024-00702-3