Thoughts on overpopulation

[nduka-san]

Some scholars think the world wil cap out at 10 billion humans.

Humans are an Invasive species and have little to no predators in the right conditions
.Using Biologly terms we would be tertiary consumers
So what are your thoughts on overpopulation and how the invaive species known as
homo-saipens got too thrive?

 

[russ_watters]

Some scholars think the world wil cap out at 10 billion humans.
Some say that the world wil colpase.

What scholars? What, exactly, do they say?

Whether humans top-out at 10 billion population or not isn't necessarily related to over-population. It may happen due to birth control/development.

I don't think there is any real consensus about a maximum carrying-capacity of Earth, but it's almost certainly vastly more than 10 billion people, and I could only see "collapse" as a non-scientific doomsday cult style prediction.

[edit] Here's a UN report citing 65 different studies with estimates ranging from 2 billion to 1 trillion:
https://na.unep.net/geas/archive/pdfs/geas_jun_12_carrying_capacity.pdf

 

[nduka-san]

https://www.livescience.com/16493-people-planet-earth-support.html

 

[russ_watters]

https://www.livescience.com/16493-people-planet-earth-support.html

Not a great source, but on this subject I think a lot of the discussion is agenda-driven, so good sources aren't easy to find.

For a start, I think by this point we've proven that Malthus's 200 year old hypothesis is wrong. I highly doubt he considered the possibility of birth control, and it runs contrary to the hypothesis.

And while lacking specifics of the one study/book the article cites, they do mention a limitation in freshwater, which is clearly false (we can turn oceans into fresh water if we choose to). And considering we already produce enough food to feed 10 billion people, that limit is clearly wrong too.
https://www.researchgate.net/publication/241746569_We_Already_Grow_Enough_Food_for_10_Billion_People_and_Still_Can't_End_Hunger

Typically what I see (as in this example) is a lack of prescience relating technology's ability to overcome needs. Pessimism seems to be the driver of such studies.

 

[nduka-san]

thanks, Russ ill try to look for better sources

 

[PeroK]

Typically what I see (as in this example) is a lack of prescience relating technology's ability to overcome needs. Pessimism seems to be the driver of such studies.

There is also the common theme of not including feedback in the analysis:

a) People want to eat meat, rather than go vegetarian.

b) We can support only 10 billion carnivores.

c) Once we have more than 10 billion people we will have starvation.

Whereas, even if this equation is true, at some point the threat of starvation will promote vegetarianism. Or, at least, a per capita reduction in meat eating.

[This common fallacy is highlighted in the book "Freakonomics". It's amazing how often you find it.]

 

[nduka-san]

There is also the common theme of not including feedback in the analysis:

a) People want to eat meat, rather than go vegetarian.

b) We can support only 10 billion carnivores.

c) Once we have more than 10 billion people we will have starvation.

Whereas, even if this equation is true, at some point the threat of starvation will promote vegetarianism. Or, at least, a per capita reduction in meat eating.

[This common fallacy is highlighted in the book "Freakonomics". It's amazing how often you find it.]

Freaky

 

[BWV]

Malthus was of course 100% correct in describing the dynamics of the pre-modern world. The population in Britain in 1766, the year of Malthus' birth had just recovered from the 50%+ population decline it suffered during the 14th century (not just the plague, but global cooling and related famines that preceded it). The population dynamics of China and other Asian countries prior to industrialization also follow Malthus. The question is how much technology can expand the limit at which Malthusian dynamics begin

Technology solutions to meat exist, either through fermentation or in vitro culture that promise to provide animal protein far more efficiently

Africa is currently the only continent with a population growing above replacement. Given the lack of infrastructure and low tech agriculture, it remains at risk of Malthusian dynamics

 

[Vanadium 50]

Humans are an Invasive species

Really?
From where exactly did they invade?

 

[BWV]

Really?
From where exactly did they invade?

a few thousand escaped from Africa about 100K years ago, and now just look at all the damage they wrought

 

[Vanadium 50]

Why are they invasive while, say, the Virginia Opossum is not?

 

[Jarvis323]

 

[nduka-san]

Really?
From where exactly did they invade?

even though this was answered earlyier i still wana respond
so human started in africa and migrated outwards going to europe and India and tons other places then when moved over to differnet evnrionments we killed the createues there and oppresed them forcing them to adjust to how we changed their habitats

this will relate in later but have you ever seen a baby pidgeon ?
most people will say no
most baby pigeons hide and are never seen until adulthood
before humans said let's COLONIZE pidgeons lived in rocky cliffs.Pidgeons adjusted somewhat well and live in nooks and cranneys in cities but some animals arent as versitale and don't survive.Heres an example white rhinos, and galapagos turtles .

 

[Vanadium 50]

So if humanity were to have remained in Africa things would be OK? What if there were 7.7B people there as opposed to 1.2B?

 

[nduka-san]

So if humanity were to have remained in Africa things would be OK? What if there were 7.7B people there as opposed to 1.2B?

thats assuming that humanity would make it to 7.7 billion if it remained in africa

 

[BWV]

thats assuming that humanity would make it to 7.7 billion if it remained in africa

Yep, never would have happened, at least according to Jared Diamond

 

[cybernetichero]

Since the definition of a feral specie is a specie that has been moved from it's original habitat to another one by humans. By definition that's also the humans themselves. There's us, the black and brown rat and the mouse. The four most successful feral vertebrates on Earth.
If we could keep to more modest desires then maybe we could survive but being "aspirational" is part of who we are.
It's not so much the population but each individual's footprint multiplied by that population. If we could all be happy with less...
This is just one of the very good reasons for a breeding license but (apart from the age old question of how do you police people's sex lives) it's a policy that would be defined by who is NOT allowed to breed and be a kind of proxy eugenics as well as being so unpopular only a suicidal politician would propose it.

 

[Vanadium 50]

Since the definition of a feral specie is a specie that has been moved from it's original habitat to another one by humans

a. speceis, not specie. Specie means coinage.
2. That is not the definition of "feral species". I am not even sure it makes sense to talk about an entire species being feral.

 

[aheight]

So what are your thoughts on overpopulation and how the invaive species known as
homo-saipens got too thrive?

I immediately recall David Attenborough in A Live on our Planet lamenting, "humans are over-running the planet." Basically I'm appalled by the matter but find comfort that Nature will find a way because I do not believe homo sapiens will actively do anything about it until catastrophe strikes and then it may be too late.

Continuing in our ways may end up burning this planet up and there is a chance the resulting catastrophes may alter the climate dramatically, extinguishing a good part of life. I've often wondered why we have never encountered any direct evidence of extraterrestrial contact. I'm beginning to think this is so because they really want nothing to do with us.

 

[cybernetichero]

a. speceis, not specie. Specie means coinage.
2. That is not the definition of "feral species". I am not even sure it makes sense to talk about an entire species being feral.

I love how you corrected me but
a. you spelled it wrong anyway and
2. you mixed up your dot point numbering.

My point stands though. No other "introduced" animal can thrive in as many habitats as us and we have artificially weighted evolutionary pressures like infant mortality from bad mutations and exposure to unfavourable weather so that natural population controls have been overridden.

It's no mystery why satellite photos of metropolitan areas look like cultures on a Petri dish. Macrocosm mimics microcosm.

 

[Vanadium 50]

You're right. The order is 1, B, III.

 

[BillTre]

feral

I think of feral animals as formerly domesticated gone wild.

here is a definition I found:
(especially of an animal) in a wild state, especially after escape from captivity or domestication.
"a feral cat"

Rats and mice are more like opportunists, taking advantage of human made environments and transportation.

Maybe rabbits in Australia would be a large population of feral animals (if they were ever domesticated).

 

[Buzz Bloom]

For a start, I think by this point we've proven that Malthus's 200 year old hypothesis is wrong.

The Malthus hypothesis of an eventual rapid human population collapse was and continues to be a plausible prediction. His error regarding how long it would take was his inability to foresee two components: (1) technology producing artificial fetilizers and faster methods of soil preparation using machinery, and (2) his belief that contraception was evil, and that it would not become a factor.

One evidence item showing that Malthus was correct is the current very high rate of the vast extinctions of non-human species due to the destruction of habitats as human population growth requires more space for housing and food production. Some of these exterminations have a clear negative effect on human food production. One current active example is the reduction of of bee population which reduces natural ferilization of food plants, although some compensation is the use of new technologoes to provide some methods of fertization not requiring bees.

A second evidence item is the out-of-control increase in fossil fuel use and its effect on global warming.

 

[russ_watters]

The Malthus hypothesis of an eventual rapid human population collapse was and continues to be a plausible prediction. His error regarding how long it would take was his inability to foresee...

He certainly could continue to be wrong until he becomes right, but I'm not a fan of moving the goalposts to infinity on a prediction about the future. It would be hard to close-out any prediction if we're allowed to do that.

But, specifically, I think those "failed to forsee" issues are a big deal. What differentiates us from yeast is our ability to control both our environment and our reproduction rate to benefit us. So while it will always be possible that we could eventually run out of new ideas/ways for defeating Malthus, I wouldn't set a date for a likely end point to his failures.

 

[BWV]

But Malthus has been right regarding pre-modern history, but he failed to predict the ability of industrialization and technology to increase agricultural productivity. The wikipedia article has this (with references)

Research indicates that technological superiority and higher land productivity had significant positive effects on population density but insignificant effects on the standard of living during the time period 1–1500 AD.[48] In addition, scholars have reported on the lack of a significant trend of wages in various places over the world for very long stretches of time.[5][49] In Babylonia during the period 1800 to 1600 BC, for example, the daily wage for a common laborer was enough to buy about 15 pounds of wheat. In Classical Athens in about 328 BC, the corresponding wage could buy about 24 pounds of wheat. In England in 1800 AD the wage was about 13 pounds of wheat.[5]:50 In spite of the technological developments across these societies, the daily wage hardly varied. In Britain between 1200 and 1800, only relatively minor fluctuations from the mean (less than a factor of two) in real wages occurred. Following depopulation by the Black Death and other epidemics, real income in Britain peaked around 1450–1500 and began declining until the British Agricultural Revolution.[50] Historian Walter Scheidel posits that waves of plague following the initial outbreak of the Black Death throughout Europe had a leveling effect that changed the ratio of land to labor, reducing the value of the former while boosting that of the latter, which lowered economic inequality by making employers and landowners less well off while improving the economic prospects and living standards of workers. He says that "the observed improvement in living standards of the laboring population was rooted in the suffering and premature death of tens of millions over the course of several generations." This leveling effect was reversed by a "demographic recovery that resulted in renewed population pressure."[51]

Robert Fogel published a study of lifespans and nutrition from about a century before Malthus to the 19th century that examined European birth and death records, military and other records of height and weight that found significant stunted height and low body weight indicative of chronic hunger and malnutrition. He also found short lifespans that he attributed to chronic malnourishment which left people susceptible to disease. Lifespans, height and weight began to steadily increase in the UK and France after 1750. Fogel's findings are consistent with estimates of available food supply.[52]

https://en.wikipedia.org/wiki/Malthusianism#cite_note-52

 

[cybernetichero]

On a side note, I have been working my way through some Star Trek DVDs given to me by a friend and nearly fell off my seat laughing when Picard mentioned in passing a delegation from a race called the "Malthusians". I bet they are fun at embassy parties.

 

[russ_watters]

But Malthus has been right regarding pre-modern history, but he failed to predict the ability of industrialization and technology to increase agricultural productivity.

It's tough for me to parse that. Malthus posed his theory in 1798, so any description of application prior to that would be history/input, not output/prediction.

Malthus's theory was that food production should follow a linear trend whereas population should follow an exponential trend. And as a result, after they cross it should cause massive famine and a substantial population die-off, even absent outside factors like climate change/disease.

The premise/model of food production seems particularly illogical to me. Since prior to modern times food production was labor intensive, food production tracked closely with the number of people available to produce food. So naturally, food production followed the same exponential curve that the population did! It doesn't seem to me that his idea ever had merit, even at the time it was written, looking backwards. It was not an accurate description of reality at the time/prior, so it is no surprise the prediction didn't come to pass.

The wikipedia article has this (with references)
https://en.wikipedia.org/wiki/Malthusianism#cite_note-52

That section of the wiki is about wages/standard of living. I see no obvious connection to Malthus's theory.

[prior post]

Malthus was of course 100% correct in describing the dynamics of the pre-modern world. The population in Britain in 1766, the year of Malthus' birth had just recovered from the 50%+ population decline it suffered during the 14th century (not just the plague, but global cooling and related famines that preceded it).

Pre-modern civilizations were fragile and susceptible to weather-induced famine and disease. That isn't what Malthus's theory was about. His theory was about self-induced failure/collapse due to a fundamental inability to produce enough food.

I suppose one could broaden the idea to include other types of catastrophes (both man-made and natural), but I don't see why such ideas should be attributed to Malthus.

 

[BWV]

Wages are a proxy for food consumption, particularly in poor societies. Here is some further info - note the increase in per capita food supply in the 14th century as the population fell by half

https://ourworldindata.org/breaking-the-malthusian-trap

 

[russ_watters]

Wages are a proxy for food consumption, particularly in poor societies. Here is some further info - note the increase in per capita food supply in the 14th century as the population fell by half

https://ourworldindata.org/breaking-the-malthusian-trap

It looks to me like the problem is that we're talking about two different things. I'm talking about the Malthusian Catastrophe, which is as I described. That's what the link the OP provided is talking about:

The late-18th century philosopher Thomas Malthus wrote these ominous words in an essay on what he saw as the dire future of humanity. Humans' unquenchable urge to reproduce, Malthus argued, would ultimately lead us to overpopulate the planet, eat up all its resources and die in a mass famine.

You're talking about a Malthusian Trap, which is a self-limiting feedback feature of standard of living in pre-modern societies. To me they don't seem to be very related - if anything, the Malthusian Trap contradicts the Malthusian Catastrophe. To me, the Malthusian Trap is a self-evident feature of pre-modern society. So if that's what you're saying he was right about, I agree, but I don't think it is related to what this thread was about.

 

[BWV]

It looks to me like the problem is that we're talking about two different things. I'm talking about the Malthusian Catastrophe, which is as I described. That's what the link the OP provided is talking about:

You're talking about a Malthusian Trap, which is a self-limiting feedback feature of standard of living in pre-modern societies. To me they don't seem to be very related - if anything, the Malthusian Trap contradicts the Malthusian Catastrophe. To me, the Malthusian Trap is a self-evident feature of pre-modern society. So if that's what you're saying he was right about, I agree, but I don't think it is related to what this thread was about.

but the OP is something of a misquote, Malthus wrote about these feedback mechanisms - war, disease, etc. not just famine. I don't really care to what exent Malthus was correct in some of the details in his writings, just interested the modern scholarship on the Malthusian trap. the reality seems to be that the catastrophes triggered by wars, diseases or natural disasters (including climate/weather) were common enough and resulted in sufficient depopulation to prevent the OP’s stereotypical malthusian famine where people are dying off from starvation presumably despite good harvests. The Little Ice Age in the 14th century and 1816 - The Year Without a Summer are good examples.

Famine seems to be the last, the most dreadful resource of nature. The power of population is so superior to the power of the Earth to produce subsistence for man, that premature death must in some shape or other visit the human race. The vices of mankind are active and able ministers of depopulation. They are the precursors in the great army of destruction, and often finish the dreadful work themselves. But should they fail in this war of extermination, sickly seasons, epidemics, pestilence, and plague advance in terrific array, and sweep off their thousands and tens of thousands. Should success be still incomplete, gigantic inevitable famine stalks in the rear, and with one mighty blow levels the population with the food of the world.

 

[Buzz Bloom]

The premise/model of food production seems particularly illogical to me. Since prior to modern times food production was labor intensive, food production tracked closely with the number of people available to produce food.

Hi russ:

I never read the original Malthus paper, so I may be incorrect in what I believe about it. I do believe that Malthus had another relvant concept besides food and the people to create it: the space in which food may be produced. This space was, and is finite, although there is more of it now then there was in the Malthus era. A lot of forests have become farms. Malthus failed to include the effect of forest destruction on climate change, which has its own impact on a future population collapse.

Regards,
Buzz

 

[BWV]

Came across this, which suggests that disease was the real check on population and was driven by density, not the availability of food.

Earth scientist Jed Kaplan and colleagues suggest that less than one-half of the land currently used for food production was used in 1600 and less than one-third in 100 CE. It is true that making more of the land available takes more work—sometimes brutally hard work, and that risks malnutrition. Again, some land couldn’t be cultivated without innovations, including heavy plows and irrigation. Nonetheless, it seems clear that throughout most of history the number of humans on Earth fluctuated far below the maximum possible.
Instead, we should probably thank (or blame) the regulatory mechanism of infection for limiting populations. As the number of people grew, population density drove up disease rates. This thinning mechanism was, in most places, probably the most powerful check on the number of people, particularly during the centuries that humans have been farmers. …And when infectious death declined in the nineteenth and twentieth centuries, population, urbanization, intensification, land use, and prosperity all climbed to historically unprecedented levels worldwide.

Although there’s a lot of interesting history in Kenny’s book, I’m not sure he does enough with this insight. To me it seems a fairly important finding that the foundation of modern technological civilization is the ability to control infectious disease. (To be fair to Malthus, he did discuss disease as one of the mechanisms that acted to limit human population growth, but he generally discounted its importance relative to food supply.) Modern economies are all fundamentally dense, urban economies–the US is 82% urban, China 60%–and this population structure cannot be sustained without a set of technologies and practices that manage infectious disease.

When industrialization and urbanization happened without those controls, as they did in early 19th-century Britain, they led to actual declines in living standards and life expectancy. Rampant disease in pre-industrial cities like ancient Rome killed off residents faster than they could reproduce, requiring a continuing inflow of migrants to maintain their population. If our current systems for controlling infectious disease weaken or fail, therefore, we’re in trouble

https://andrewbatson.com/2021/03/16/misunderstanding-malthus-mistake/

 

[Klystron]

{snip}
this will relate in later but have you ever seen a baby pidgeon ?
most people will say no
most baby pigeons hide and are never seen until adulthood
before humans said let's COLONIZE pidgeons lived in rocky cliffs.Pidgeons adjusted somewhat well and live in nooks and cranneys in cities {snip}

After reading this interesting thread again, I can answer your question for western USA.

As a casual birdwatcher I have often seen young pigeons once they grow feathers and learn to fly. Young pigeons appear almost identical to adult birds but noticeably smaller by comparison. I have seen youngsters, usually in the company of adults, learning which items to eat, avoid danger and how to interact with other pigeons in their flock.

After this stage I understand most pigeons form 'teen flocks' or social groups within the larger community while reaching mating maturity, making size comparisons with adults even more difficult. Pigeon hobbyists have specific names for each age group and can tell 'children' from adults by behavior as well as size.

AFAIK unless you explore nesting sites, you almost never see live baby birds of any kind in the wild before fledging. So, the statement about baby pigeons hiding in seclusion applies to almost any bird species. I have seen dead baby pigeons fallen from nests and captured by predators.

Like chickens from southeast Asia, pigeons from north Africa were introduced to America as a popular food source.