What is the max population North America can support?

[LNSS]

At first glance, North America seems like the best location on Earth to build a civilization. It's big, surrounded/protected by three oceans, mostly flat but also has some big mountain ranges to provide a lot of rivers and thus agriculture, etc.

Yet it has never reached the same population as places like India or China which in theory are not as good. What's a good POD to give North America (from Panama to the Arctic, including the Caribbean) the largest possible population, and what would that population be?

 

[Pedersen]

In theory, as argued by e.g. Ester Boserup, Henry George, Hans Rosling and many others, there really isn't a limit to the size of the human population.

Malthus, Club of Rome and others disagree with this, but have time and time again been proven wrong by the historical development.

If you want a large NA population, simply have humans develop there or arrive earliere.

 

[Workable Goblin]

In theory, as argued by e.g. Ester Boserup, Henry George, Hans Rosling and many others, there really isn't a limit to the size of the human population.

Well, no, there are definite physical limits. If you converted all matter in the solar system into humans, for instance, you would have about 3 * 10^28 people (or about thirty thousand trillion trillion), at least for a very brief period of time. You can't really have more people than that, at least without harvesting matter from other solar systems and bringing it back here, and even then you would (eventually) run into problems with gravitational collapse into a neutron "star" or black hole. In practice this is obviously not possible since you would need to reserve large amounts of mass for breathing air, drinking water, habitats, other life forms, power generation, etc., and anyway the overwhelming majority of the solar system's mass is in the Sun, which is hardly useful (as it is nearly all hydrogen and helium). So you probably physically cannot have more than some trillions of people in the solar system given the actual amount of matter that exists to house and provide for them.

Leaving that aside, at any given technological level short of the level needed to disassemble planets and turn them into habitats there are also separate limits as to how many people can be supported by a given area of land, particularly based on food production capabilities. Clearly, gatherer-hunters could not support as large a population on a given piece of terrain as farmers, and clearly modern farmers with heavy inputs of various chemicals and specially bred plants can support more people than early farmers with barely domesticated crops. Of course, this means that the question isn't well-defined without specifying a time period...I guess we're talking about "after 1900," so the answer to that question is probably "definitely over a billion, in theory," but in practice populations much higher than the current amount (perhaps close to 500 million or a bit higher) are probably not possible, not because of any "limits to growth" but because of prosperity and the resulting low birth rates, as well as limits to immigration.

 

[Pedersen]

Well, no, there are definite physical limits. If you converted all matter in the solar system into humans, for instance, you would have about 3 * 10^28 people (or about thirty thousand trillion trillion), at least for a very brief period of time. You can't really have more people than that, at least without harvesting matter from other solar systems and bringing it back here, and even then you would (eventually) run into problems with gravitational collapse into a neutron "star" or black hole. In practice this is obviously not possible since you would need to reserve large amounts of mass for breathing air, drinking water, habitats, other life forms, power generation, etc., and anyway the overwhelming majority of the solar system's mass is in the Sun, which is hardly useful (as it is nearly all hydrogen and helium). So you probably physically cannot have more than some trillions of people in the solar system given the actual amount of matter that exists to house and provide for them.

Well, that is assuming matter can't be imported into the solar system or that humans will always require matter or that humans can only exist in this solar system. Obviously, if you make assumptions like Malthus or the Club of Rome did which prelude technological development, there will logically be limits - and equally obviously, such assumptions about peak technology have consistently been proved wrong throughout history. I totally get the religious attractiveness about believing in peak technology, but it is as likely to be true as the Christian concept of heaven.

Leaving that aside, at any given technological level short of the level needed to disassemble planets and turn them into habitats there are also separate limits as to how many people can be supported by a given area of land, particularly based on food production capabilities. Clearly, gatherer-hunters could not support as large a population on a given piece of terrain as farmers, and clearly modern farmers with heavy inputs of various chemicals and specially bred plants can support more people than early farmers with barely domesticated crops. Of course, this means that the question isn't well-defined without specifying a time period...I guess we're talking about "after 1900," so the answer to that question is probably "definitely over a billion, in theory," but in practice populations much higher than the current amount (perhaps close to 500 million or a bit higher) are probably not possible, not because of any "limits to growth" but because of prosperity and the resulting low birth rates, as well as limits to immigration.

True, with a PoD in 1900 and afterwards, it is extremely unlikely to get to say a factor 2 over OTL NA population, which btw is ca. 580 million today if we are using OP's definition of NA (Panama to Artic + Caribbean) and not the smaller definition of NA as simply USA + Canada. PoD after 1900 that could raise population include increased immigration, increased religiousness, cultural norms support large families or other factors leading to higher childbirth.

 

[Workable Goblin]

Well, that is assuming matter can't be imported into the solar system or that humans will always require matter or that humans can only exist in this solar system.

I actually did specifically say that this could be gotten around by importing more matter into the solar system and even pointed out that you could only import so much matter before the solar system would undergo gravitational collapse. I also repeatedly said the number of humans in the solar system specifically to deal with the latter objection--any number of people could be living in other solar systems, of course (though even there you could calculate limits on the total number of humans that could exist given the actual available mass in the universe), but this wouldn't increase the number of people living in the solar system itself anymore than the population of North America increased the population of Europe. As for humans not requiring matter any more, that would both require magic (merely uploading minds would not do it; they would still require matter for the computers running their uploaded minds and for whatever power sources were powering them) and, more importantly, would make them not human in the sense of not being biological entities classified as "Homo sapiens". I did not intend to calculate the number of intelligent entities that could exist in the solar system (much less the universe), but rather merely the number of humans.

In any case, at any given point it is never clear that technological advances definitely will come along to allow a higher population, yes. They didn't for long periods of time in human history, and there are definitely some technologies people have dreamed up that are not possible in reality (perpetual motion machines of the second kind, for example), so it is clearly not the case that just because we can imagine the possibility of future technologies or specific future technologies that they will definitely be possible. Other technologies might have been possible but remained marginal or merely conceptual without ever being built. It is quite possible that building space habitats or engaging in interstellar travel and colonization will fall into one of those categories (I lean towards the second one, actually, due to population decline and robotization making them pointless).

True, with a PoD in 1900 and afterwards, it is extremely unlikely to get to say a factor 2 over OTL NA population, which btw is ca. 580 million today if we are using OP's definition of NA (Panama to Artic + Caribbean) and not the smaller definition of NA as simply USA + Canada. PoD after 1900 that could raise population include increased immigration, increased religiousness, cultural norms support large families or other factors leading to higher childbirth.

Possibly, but the United States was already unusual religious (and high religiousness seemingly creates a "snapback" effect where subsequent declines in birthrates are particularly sharp and rapid--see Iran for an example). Cultural norms might do the trick, but it's not totally clear what those are. Probably the most clear-cut possibility is higher immigration, but that's politically difficult...

The source I was using said North America's population was about 400 million, and I guesstimated about 450 million based on the United States and Mexico, sort of ignoring all of the other countries as collectively much smaller. So that explains that.

 

[Pedersen]

In any case, at any given point it is never clear that technological advances definitely will come along to allow a higher population, yes.

Well, total human population has consistently grown for the past 70 or so millenias.

There have been local setbacks or a couple of decades with negative population growth here and there, but if you compare from one millennia to another, it is a pretty one-sided story.

 

[Workable Goblin]

Well, total human population has consistently grown for the past 70 or so millenias.

Has it really? I don't think there's any evidence of substantial global population growth until the development of agriculture, which definitely permitted far larger populations to be sustained in an area than was previously possible. And even after that there are definitely centuries and even millennia when it's not clear that there was any substantial population growth versus the number of people alive being approximately constant. The fact that the estimates for these pre-modern eras often have large error bars associated with them makes confident statements like this even harder to sustain.

There have been local setbacks or a couple of decades with negative population growth here and there, but if you compare from one millennia to another, it is a pretty one-sided story

Not really. If you look at the figures, growth was sluggish at best throughout most of human history, with populations remaining practically constant until urbanization occurred. Even then, there were definitely periods with virtually zero population growth, even prolonged ones--the year 0 and the year 1000, for instance, have practically the same population (especially taking into account error bars) in some estimates. Even where it did grow, the growth was extremely slow by modern standards. Overall, the story I am getting is one in which substantial limits to growth existed that did, in fact, constrain population growth relative to the theoretical level and resulted in sluggish to no growth over prolonged periods of time, until technologies were invented that did overcome those limits. But of course someone in 500 A.D. could not have foreseen the development of better agricultural techniques or medicines that would allow this descendants 1 300 years later to rapidly grow their populations, nor would those advances have been particularly relevant to him if he was trying to figure out how many people could live in Europe (or whatever).

 

[Analytical Engine]

Assuming you don't mind importing food, and you define North America as stretching from the north pole to the southern border of Panama...

Probably about a billion. Considering that area is just shy of 600 million as it is.

North America - Wikipedia

en.wikipedia.org

Well, no, there are definite physical limits. If you converted all matter in the solar system into humans, for instance, you would have about 3 * 10^28 people (or about thirty thousand trillion trillion), at least for a very brief period of time. You can't really have more people than that, at least without harvesting matter from other solar systems and bringing it back here, and even then you would (eventually) run into problems with gravitational collapse into a neutron "star" or black hole. In practice this is obviously not possible since you would need to reserve large amounts of mass for breathing air, drinking water, habitats, other life forms, power generation, etc., and anyway the overwhelming majority of the solar system's mass is in the Sun, which is hardly useful (as it is nearly all hydrogen and helium). So you probably physically cannot have more than some trillions of people in the solar system given the actual amount of matter that exists to house and provide for them.

That's assuming you are restricting yourself to physical humans. If you converted all that matter into a dyson brain and its attendant power source, and allowed for mass-scale nuclear transmutation, it could sustain a lot more.

 

[Workable Goblin]

That's assuming you are restricting yourself to physical humans. If you converted all that matter into a dyson brain and its attendant power source, and allowed for mass-scale nuclear transmutation, it could sustain a lot more.

I did specifically mention that I was talking about physical humans in my other post, yes. In any case, I would not classify an uploaded mind as "human" ("sapient and worth of rights," yes, but not "human")

 

[Pedersen]

Has it really? I don't think there's any evidence of substantial global population growth until the development of agriculture, which definitely permitted far larger populations to be sustained in an area than was previously possible.

The consensus is that there was steady, but slow growth. A few outliers doesn't change that.

For the sake of argument, let's use the HYDE project, who estimates world population at

• 10.000 in -70bc
• 2m in -10k bc
• 18m in -5kbc
• 188m in year 1 ad
• 295m in year 1000
• 6145m in 2000

Just because you have exponential growth from 1000 to 2000 ad, doesn't mean that there wasn't substantial growth before that.

And even after that there are definitely centuries and even millennia when it's not clear that there was any substantial population growth versus the number of people alive being approximately constant. The fact that the estimates for these pre-modern eras often have large error bars associated with them makes confident statements like this even harder to sustain.

Which, if you believe your own argument, would mean that you can't claim that there wasn't growth

Not really. If you look at the figures, growth was sluggish at best throughout most of human history, with populations remaining practically constant until urbanization occurred.

From 2m to 295m is hardly "sluggish".

Even then, there were definitely periods with virtually zero population growth, even prolonged ones--the year 0 and the year 1000, for instance, have practically the same population (especially taking into account error bars) in some estimates. Even where it did grow, the growth was extremely slow by modern standards. Overall, the story I am getting is one in which substantial limits to growth existed that did, in fact, constrain population growth relative to the theoretical level and resulted in sluggish to no growth over prolonged periods of time, until technologies were invented that did overcome those limits. But of course someone in 500 A.D. could not have foreseen the development of better agricultural techniques or medicines that would allow this descendants 1 300 years later to rapidly grow their populations, nor would those advances have been particularly relevant to him if he was trying to figure out how many people could live in Europe (or whatever).

Which is the point - why should we believe that we can predict what technologies will exist 1300 years from now? Most unlikely, it will be stuff that we can't even imagine.

 

[Gabingston]

If the land area of the contiguous United States (internal waters like the Great Lakes are excluded) had the same population density as Spain (243.5 people per square mile) the contiguous U.S. would have a population of 720 Million. Much of the Western U.S. is near uninhabitable, which is why I chose one of Europe's more open countries, but I see no reason why North America east of the Mississippi couldn't have a population density similar to Western Europe. I think North America could support well over a billion people, maybe even two billion.

 

[Arkenfolm]

Well, that is assuming matter can't be imported into the solar system or that humans will always require matter or that humans can only exist in this solar system. Obviously, if you make assumptions like Malthus or the Club of Rome did which prelude technological development, there will logically be limits - and equally obviously, such assumptions about peak technology have consistently been proved wrong throughout history. I totally get the religious attractiveness about believing in peak technology, but it is as likely to be true as the Christian concept of heaven.

The maximum population of North America from this argument is "until the continent bakes itself in the waste heat of humans." It's estimated Earth could probably support 10 trillion people before the amount of heat needed for logistics etc. burns up the planet, so since North America has about 5% of the land area of Earth, this means about 500 billion people. In practice, this would include many blocks of ocean near North America (as seasteads, underwater cities, etc.) so would probably be another few hundred billion people.

Not really. If you look at the figures, growth was sluggish at best throughout most of human history, with populations remaining practically constant until urbanization occurred. Even then, there were definitely periods with virtually zero population growth, even prolonged ones--the year 0 and the year 1000, for instance, have practically the same population (especially taking into account error bars) in some estimates. Even where it did grow, the growth was extremely slow by modern standards. Overall, the story I am getting is one in which substantial limits to growth existed that did, in fact, constrain population growth relative to the theoretical level and resulted in sluggish to no growth over prolonged periods of time, until technologies were invented that did overcome those limits. But of course someone in 500 A.D. could not have foreseen the development of better agricultural techniques or medicines that would allow this descendants 1 300 years later to rapidly grow their populations, nor would those advances have been particularly relevant to him if he was trying to figure out how many people could live in Europe (or whatever).

The population merely fluctuated regionally (and in the case of North America, locally) between 1 and 1000 AD. You can find huge distinctions, like for instance compare Germany in 1 AD to Germany in 1000 AD.

 

[Workable Goblin]

The consensus is that there was steady, but slow growth. A few outliers doesn't change that.

You'll note that I specifically said "before agriculture," i.e. before the -10k B.C. point in your list. Following the development of agriculture there was of course substantial population growth over time, but before that not so much. I repeatedly noted that I was specifically claiming that pre-agricultural populations were relatively constant (once all of the continents had been colonized) and merely that while there was population growth after the invention of agriculture it was slow and not necessarily very steady, with periods where growth stalled.

For the sake of argument, let's use the HYDE project, who estimates world population at

• 10.000 in -70bc
• 2m in -10k bc
• 18m in -5kbc
• 188m in year 1 ad
• 295m in year 1000
• 6145m in 2000

Just because you have exponential growth from 1000 to 2000 ad, doesn't mean that there wasn't substantial growth before that.

In fact I don't accept using the HYDE project "for the sake of argument". The very fact that you have to pick a specific estimate, when there are many estimates out there with sometimes substantially varying values (for example, populations as high as 300 million for 1 A.D.) shows that this is not reliable evidence that the population has inevitably grown by a substantial amount every century and millennium since humanity evolved. It certainly does not prove that there are no periods when there was global regression in population, as you claimed.

Also, the very long timescales involved show that even taking those estimates at face value there was not substantial growth over long periods. In fact, growth was quite slow! Like I show below, substantially below 1% per year, or even 0.1%.

Which, if you believe your own argument, would mean that you can't claim that there wasn't growth

That misunderstands statistics rather thoroughly. The null hypothesis is (normally, and certainly in this specific case) that nothing happened, and the job of the evidence is to prove that it did happen. If the error bars overlap, particularly if they substantially overlap, then there is no way to reject the null hypothesis and therefore no reason to believe, on a statistical level, that anything happened. In other words, what they prove is that there is no evidence of growth occurring. They are not evidence that there was growth occurring.

In any case, I am not denying that there was growth on very long timescales, just that there were substantial periods where it is not clear that there was any substantial growth between one tick and another--again, the 1 A.D. and 1000 A.D. examples are particularly instructive here, because the large error bars make it plausible that there was actually a higher population in 1 A.D. than in 1000 A.D.

From 2m to 295m is hardly "sluggish".

It is if it takes eleven thousand years for that growth to take place. That's a growth rate of just 0.045%. That's sluggish by any reasonable standard--over the course of a century, the global population would only increase 4.6%. To put it another way, if at the beginning of one century there were one hundred million people on Earth, at the end of it there would be about one hundred and five million. Barely noticeable, spread out over the whole planet. Putting it differently, if that growth rate had continued, we would be looking at reaching our current actual population in about six thousand years. Slow!

Which is the point - why should we believe that we can predict what technologies will exist 1300 years from now? Most unlikely, it will be stuff that we can't even imagine.

Well, we do have a rather better understanding of the nature of the universe than they did in 500 A.D.; there is a far greater chance that the things which we say can't exist actually cannot, physically, exist (just like the example I used of the perpetual motion machine of the second kind). But as I said the actual point is that saying "oh, there might be magical technology that would enable trillions of people to live in North America" is not particularly helpful for estimating the number that could actually live there now, when such magical technology doesn't exist.

The population merely fluctuated regionally (and in the case of North America, locally) between 1 and 1000 AD. You can find huge distinctions, like for instance compare Germany in 1 AD to Germany in 1000 AD.

We are specifically discussing changes in global population, not regional or local populations. If the global population remains constant and is merely redistributed from one place to another, that still means there was no global population growth.

 

[Fuzzy Dunlop]

At first glance, North America seems like the best location on Earth to build a civilization. It's big, surrounded/protected by three oceans, mostly flat but also has some big mountain ranges to provide a lot of rivers and thus agriculture, etc.

Yet it has never reached the same population as places like India or China which in theory are not as good. What's a good POD to give North America (from Panama to the Arctic, including the Caribbean) the largest possible population, and what would that population be?

According to web sources NatGeo, Britannica etc around 35 million Europeans emigrated to USA to the USA alone between 1820 to 1920 which increased by a factor of 5 by natural increase ending up at 170 plus million.

Could we have 1 million p/y instead of 350,000?