Population Control

[Vander]

So Earth's population is projected to be around 10 billion by 2050, and possibly 16 billion by 2100. At some point, population control will likely be necessary. What do you think population control would look like in America? Would we have to rely on informed citizens doing their part to minimize population growth? Tax penalties for multiple births? Tax incentives for sterilization? I think we can probably all agree that any forced restriction would be decidedly unconstitutional at least, and draconian at best.

Lets speculate!

[Nightshade]

So Earth's population is projected to be around 10 billion by 2050, and possibly 16 billion by 2100. At some point, population control will likely be necessary. What do you think population control would look like in America? Would we have to rely on informed citizens doing their part to minimize population growth? Tax penalties for multiple births? Tax incentives for sterilization? I think we can probably all agree that any forced restriction would be decidedly unconstitutional at least, and draconian at best.

Lets speculate!

I'm all for democrat birth control.

[callmeslick]

the human population of earth is the elephant in the room around environmental issues. Ongoing population growth is not sustainable, and likely the CURRENT levels of inhabitants isn't sustainable. Will have to ponder what to do, versus allowing population dynamics to do its ugly job, and get back later today.

[woodchip]

There is one word for it. Economics. Population not expanding, economy not expanding. The most striking example is China who has now changed their 1 child policy to two. Germany is allowing all those migrants in because their population was starting to shrink. The US also is faced with the same dilemma as is most of the industrialized west. So the quandary is, to keep the economy growing you need population growth and if population keeps growing you eat yourself out house and home. So how do you balance the two?

[snoopy]

I have a theory that a lot of people won't like to hear: war.

I think resource limitations incubate war... and war decimates populations. Those two thoughts lead me to predict that the human population will re-balance itself through war.

[Foil]

At some point, population control will likely be necessary.

I disagree with this premise.

Population growth has already slowed significantly, and will continue to do so as contraception improves worldwide.

I see no reason to repeat the rampant "global starvation" speculation of the 1970s.

[Vander]

versus allowing population dynamics to do its ugly job

Doing nothing is the obvious option. Let nature run its course. At some point an equilibrium will be reached. But is the outcome of an environmentally driven population reduction more favorable than a controlled descent? I wouldn't think so, as we'll scratch and claw against it, leaving the planet able to sustain smaller and smaller populations. Kick out enough legs of a chair, and the chair no longer works. Not to mention the strife and calamity of the scratching and clawing.

Of course, "doing something" requires people to realize something has to be done in the first place, and that isn't all that likely. Hysteria ensues when you talk about limiting someones ability to purchase an SUV. What do you think it will be like when you talk about limiting their number of children?

So the quandary is, to keep the economy growing you need population growth and if population keeps growing you eat yourself out house and home. So how do you balance the two?

This is sort of what I was getting at in this thread. I don't see our current systems as compatible with sustainable human habitation. Our current systems of civilization were created when the size of the Earth was unlimited. Run out of space? Go further west. The realization that the Earth is finite is a fairly recent thing.

I have a theory that a lot of people won't like to hear: war.

I would say that's probably likely, if only because we have war without population as a cause. But I don't think it would be useful as a method of achieving sustainable equilibrium, and definitely not one I would prefer employed. It's a bit like sitting back and waiting for a global pandemic to wipe out half the population. It's not really a plan.

Population growth has already slowed significantly, and will continue to do so as contraception improves worldwide.

It's a definite possibility, but slowed growth is still growth! I'm sure there is bias in projections, in that it's harder to project decline because everything in the past shows growth. But this is kind of beside the topic. Speculate! I'm interested in finding out how people would envision population control in America. How could it coexist within our fundamental perceptions of liberty?

[Lothar]

At some point, population control will likely be necessary.

I disagree with this premise.

Population growth has already slowed significantly, and will continue to do so as contraception improves worldwide.

I see no reason to repeat the rampant "global starvation" speculation of the 1970s.

Exactly.

People thought population would grow unbounded back in like the 1700s. By the 1830s we knew that wasn't true (look up the Verhulst equation.) Population growth decelerates as population gets near the steady-state capacity of the environment. Under normal circumstances, if the environment can handle ~12 billion people sustainably, population will grow to ~12 billion people and then level off.

There are rare circumstances where something catastrophic happens. One example is the Kaibab deer population, which was a scenario where all of the predators were removed from the Kaibab plateau resulting in a sudden population boom of deer, which overwhelmed the local food sources and caused a population crash. One of the reasons this could happen is that the time it took for the population to quintuple was much less than the average deer lifespan. That's not a realistic concern with human population.

All of the data about human population suggests a steady-state population in the 10-13 billion range; growth peaked in about 1960 in percentage terms and 1980 in absolute terms, and has been steadily decelerating since then. Is a global population of 10-13 billion humans sustainable? Yes, though not at typical American consumption levels for the entire population. (And it doesn't require abject poverty for the majority of the world, either -- just not absolutely lush comfort.)

[callmeslick]

I have a theory that a lot of people won't like to hear: war.

I think resource limitations incubate war... and war decimates populations. Those two thoughts lead me to predict that the human population will re-balance itself through war.

that is sort of the crux of the population dynamics I was alluding to. Any overpopulated species either dies off of disease, starvation or internecine violence.

[callmeslick]

need a break from a day of writing letters and paying bills, so here's my two cents.

Is the human race overpopulated already? You betcha, hence the die off of a host of species which has been well documented. You see, that's how it works for a while in a diverse population of species. The dominant species can overpopulate at the expense of the others until the balance gets too out of whack. However, any of you suggesting that we are just fine and not to worry are GROSSLY underestimating the drain on resources the current population of humans is exacting.

Any continuation(and one cannot suppose this won't happen) of the even slight steady rise of Homo Sapiens on the planet inexorably will lead to a population crash. That might, as I noted above, come via disease or famine(and is, already, to some extent)increasing. Most likely, and most common with lab observations, is an increase in violence leading to large numbers of deaths, thus, leaving room for the survivors. Now, in the context of modern man, such violence with our technologies carries the very real risk of destroying as much by way of usable resources as population, so, the pressures will remain.

Overall, it isn't a pretty picture. There is little that will be done, not that it couldn't be, but forcing radical birthrate reductions isn't going to fly. Finally, somewhere above, I think it was woody who suggested that more people equals greater economic growth. Sometimes yes, but in the modern economy, technological advances to productivity count for far more.

[Tunnelcat]

So Earth's population is projected to be around 10 billion by 2050, and possibly 16 billion by 2100. At some point, population control will likely be necessary. What do you think population control would look like in America? Would we have to rely on informed citizens doing their part to minimize population growth? Tax penalties for multiple births? Tax incentives for sterilization? I think we can probably all agree that any forced restriction would be decidedly unconstitutional at least, and draconian at best.

Lets speculate!

I'm all for democrat birth control.

Now, wouldn't that be a little boring?

[Lothar]

Any continuation(and one cannot suppose this won't happen) of the even slight steady rise of Homo Sapiens on the planet inexorably will lead to a population crash

I studied population dynamics in grad school.

Humanity is not on its way toward a population crash. We are not the kaibab deer. The growth rates and capacities are much more predictable. Humanity is, at worst, on its way to a slow multi-generational decline after a slightly-too-high peak, and some degree of reduced consumption from the most wasteful segments of developed society. Meh.

[callmeslick]

I'd disagree, because the only thing cushioning the crash is the effect on other species prior to the precipice.

[Lothar]

I disagree with your disagreement. There's nothing "cushioning the crash", there simply isn't a crash.

[Foil]

From what I understand of population/resource dynamics (which admittedly is mostly just the general math principles involved), I would expect to see an eventual peak, but I don't see a mechanism that would cause a crash.

So what are folks seeing that would cause a crash, rather than stabilization around a peak supportable population size?

[callmeslick]

From what I understand of population/resource dynamics (which admittedly is mostly just the general math principles involved), I would expect to see an eventual peak, but I don't see a mechanism that would cause a crash.

So what are folks seeing that would cause a crash, rather than stabilization around a peak supportable population size?

admittedly, I studied the matter from a different perspective as a biology major. The fact is that such smooth peaks only work when the ecosystem is balanced and there is adequate predation/limitation on all species. With humans, you don't have that. Our situation is akin to a scenario often tested with smaller mammals, where the population can breed unchecked with no modification from other species or the like. What happens then in isolation is a steep crash, with disease and starvation due to limited resources, and, variant with species, violence leading to a steep decline in population, which then rebounds over time and repeats. In a real-world scenario, things are complicated by the presence of other species, none of which provide predation upon humans in great numbers. The food/water pressure gets applied to those species first, leading to die-offs of other species, but eventually, the whole system should get so grossly out of balance as to imply a likely crash for humans themselves.

In short, there is no real stabilization as long as man can take the resources from other species, but when that point is reached where such isn't feasable, look out.

[Jeff250]

I don't really understand the intuition behind the overpopulation argument. If you look at the indicators that you would actually be concerned about (% of people hungry, % without access to healthcare, and so on), they are consistently improving with time, despite the human population continuing to grow, thanks in a large part due to advancements in technology. I'm not convinced of this presumption of finite resources...

[callmeslick]

I don't really understand the intuition behind the overpopulation argument. If you look at the indicators that you would actually be concerned about (% of people hungry, % without access to healthcare, and so on), they are consistently improving with time, despite the human population continuing to grow, thanks in a large part due to advancements in technology. I'm not convinced of this presumption of finite resources...

technological development IS a modifying factor, but you'd have to look real carefully at loss of finite resources. It's a complex bit of guesswork, to be honest. Well worth pondering, studying and getting right.

[Lothar]

The fact is that such smooth peaks only work when the ecosystem is balanced and there is adequate predation/limitation on all species. With humans, you don't have that.

You don't need "predation" per se, you just need factors that reduce net population growth as carrying capacity is approached. This can take the form of an increase in death rate, or of a decrease in birth rate, or both. (The Kaibab deer didn't have either, which is why they had the big boom and crash, and are so commonly referenced in population dynamics texts.)

For humans, death rate continues to decrease due to technological factors, but birth rate is decreasing faster due to social/cultural/educational factors. People have better knowledge of how to prevent pregnancy, and are becoming more and more likely to both delay having their first child and to have fewer overall. That's not just in the US or Europe; even the poorest countries in the world are seeing a slow but steady decline in overall birth rate. India has dropped from 35/1000 to 20/1000 (crude birth rate) since 1980. Worldwide the drop is from around 29 to 19 in the same time period.

World population growth rate peaked in the 1960s (at 2.2% per year; it's declined to about 1.1% per year) and absolute population growth peaked in the 1980s (at +92 million in 1987; it's declined to +80 million now). All of the credible models, from biologists, ecologists, and large agencies like the UN, have human population growth slowing to a crawl in the next century or so, and peaking anywhere from 10 to 13 billion.

[callmeslick]

now, Lothar, the question will be whether mankind will have depleted, or ruined, sufficient resources to make any life sustainable by that point.

[Tunnelcat]

Resources, plagues or natural catastrophes. Since we don't have any natural predators or a way off this planet, that's what will be the ultimate control of our human population. Deer studies have looked at this very problem and found that as long as there is abundant food, the deer population will explode. It won't crash until their food runs out, the weather gets too severe, illness runs rampant or predators become too numerous. Population is all about balance, and we humans have changed the way nature controls animal populations. Unless we can invent our way out of the situation, I don't see a very pleasant living situation for humanity in the future. Of course, in about 4 billion years, the sun will expand and solve our problem, if we're still around that is.

This is for you Foil, since you're the mathematician. The site may be biased towards population control, but maybe you can make some sense out of it, or tell me if it even makes sense.

http://arachnoid.com/lutusp/populati.html

[Foil]

This is for you Foil, since you're the mathematician. The site may be biased towards population control, but maybe you can make some sense out of it, or tell me if it even makes sense.

http://arachnoid.com/lutusp/populati.html

It's a simple growth equation, with some added commentary. (It honestly appears to have been written up in order to try to bolster the comments at the bottom.)

The problem is that it assumes a constant growth rate, which really makes no sense in any population model.

[Lothar]

now, Lothar, the question will be whether mankind will have depleted, or ruined, sufficient resources to make any life sustainable by that point.

Probably not. But we probably will have to rely considerably less on fossil fuels and other non-renewable resources.

Deer studies have looked at this very problem and found that as long as there is abundant food, the deer population will explode

Referenced above. Humans are different because we slow our own reproduction in a way that deer don't.

This is for you Foil, since you're the mathematician. The site may be biased towards population control, but maybe you can make some sense out of it, or tell me if it even makes sense.

http://arachnoid.com/lutusp/populati.html

The core equation he uses comes from Thomas Malthus. It was state of the art in 1798, and known to be inaccurate by 1838 when Verhulst wrote the Logistic equation -- which he mentions is "better" in the initial paragraph, but then ignores. (I recognize lutusp from Hacker News; he's sometimes brilliant, but not on this subject.)

It's true that a constant population growth rate of 1.1% would result in a doubling in about 63 years, to around 14 billion. But I snuck the word "constant" in there. The growth rate itself is dropping. The US Census bureau estimates a growth rate of under 1% by the end of the decade, and under 0.5% before 2050. Which is consistent with Logistic (Verhulst) growth, not exponential growth.

Every serious book out there on mathematical biology, mathematical ecology, or population dynamics will give a paragraph or two to Malthus / constant growth rate / exponential growth and show the equation, and then immediately tell you it's wrong. For example, I just pulled J.D. Murray's "Mathematical Biology" text (3rd edition, Volume I) off of my shelf. It introduces the Malthus equation on page 2, calls it "unrealistic" and "ultimately quantitatively wrong", and then introduces Verhulst on page 3. Likewise, Mark Kot (who was on my thesis committee) introduces Malthus' equation on page 3 of "Elements of Mathematical Ecology", and then refers to "several defects with this simple exponential model", eventually calling it "patently unrealistic", before introducing the Verhulst equation on page 7.

http://www.growth-dynamics.com/articles ... age004.gif shows the difference between the exponential curve lutusp is expecting (dark) and the logistic curve everybody credible expects (light, with actual data overlaid).

[Tunnelcat]

This is for you Foil, since you're the mathematician. The site may be biased towards population control, but maybe you can make some sense out of it, or tell me if it even makes sense.

http://arachnoid.com/lutusp/populati.html

It's a simple growth equation, with some added commentary. (It honestly appears to have been written up in order to try to bolster the comments at the bottom.)

The problem is that it assumes a constant growth rate, which really makes no sense in any population model.

You're right. Our population growth rate isn't constant, and as you pointed out before, birth rates have been trending down, so I think that site was more scare than fact. I needed you to plow through the math, because it didn't look simple to me.

There are other factors such a whether a nation is pre- or post-industrial, the local availability of resources and birth/death rates in an area. I did find this article however and you have to read through the first 8 pages to get all the meat. Human population metrics are far more complex than I thought. All this assumes that no major outside disaster strikes the planet however. Still, you'll have to admit that the earth doesn't have the resources for every current third world country to rise up out of poverty and live at the current economic level we live at in the U.S. and Europe. We just don't have the resources to go around. In order for those people to rise up economically, we have to sink down economically.

https://www.learner.org/courses/envsci/ ... 5&secNum=1

[Foil]

Don't credit me, tc. Lothar is the applied mathematician here with experience in population dynamics (as evidenced by his post).

[callmeslick]

fantastic math lesson, guys!! It will be interesting to see the far more complex equations going forward(Lothar and I touched on the loss of resources issue, there are others, many utterly unpredictable(extreme weather events, unforseen consequences from 'minor' species in the ecosystem, etc). Fun to ponder, for sure!

[Vander]

So what are folks seeing that would cause a crash, rather than stabilization around a peak supportable population size?

The doomsday scenario I envision is resource/food web collapse caused by the our ability to harvest at a rate that outpaces replenishment and the lag time between the two. Basically hitting an unsustainable peak, and over-harvesting to support it at the expensive of future harvest.

Another of my worries is that we don't fully understand the interconnected nature of our ecosystem, leaving us with blind spots when extrapolating our effects on it. We don't know what the peak population Earth's ecosystem can sustainably support is, or how to fully exist within it at its limits. Since we only get one shot at all this, I tend to think we should be very conservative in our approach to these limits and their unknown unknowns.

Incorporating the tyranny of sustainability into our doctrines of liberty and the free market before the capacity for sustainability is squandered. That's the big challenge I see before us.

But like I've said before, lets speculate! Speculate that there is a need for population control. How would that work in a place like the United States? How do you balance it with the fundamental liberties we hold so dear?

[Spidey]

Population growth can probably be controlled in this country by controlling immigration and letting the rest take care of itself.

So I don’t really see a conflict between our rights and this particular problem.

The real problem is in lesser developed countries, because developed countries seem to develop a natural population control.

What we really need to do in my opinion is get our budget in control so we can build the water storage and distribution systems we will need in the future to mitigate both population and climate change.

[Tunnelcat]

We already have China as an example. Even with their one child policy, the Chinese population went from 972 million in 1979 to 1.343 billion in 2012,a 138% growth during that period, although their birth rates have slowed recently. Then there's India, who's population in 1979 was 671 million, which had climbed to 1.205 billion by 2012, 180% higher than in 1979. By 2027, both countries will reach a population of about 1.4 billion, but that estimate was calculated before China's one child policy was changed to the 2 child policy this year. Chinese birth rates will most certainly rise now. Even if birth rates were to slow in these countries, there is still the issue of resource allocation along with the rising standard of living in those countries. Are there enough resources to go around in a world where large formally third world countries become developed countries, or will developed countries like the U.S. and those in Europe be forced to lower their standards of living because there just isn't enough to go around?