Sep 28 2009
The Overpopulation Hubbub
The question of human overpopulation of the earth is one of those empirical scientific questions that garners a strange amount of emotional opinion. It is as if the sense of overcrowding and depleting resources triggers something primal in our monkey brains. On the other side, we resent being told to curb what is perhaps our strongest natural instinct – to make more versions of our genome.
Another feature of this debate that encourages or at least allows emotion to reign over data is that the core questions involve predicting the future. We are very bad at predicting the future. Predicting the future is really just an exercise in projecting our biases onto the future. The best we can do is extrapolate current trends forward, but there are often multiple overlapping trends that we can choose from, some trends are really cyclical, and the appropriate curve (linear, geometric, exponential) may not be obvious.
It is also important to identify in a controversy where there are value judgments that cannot be resolved objectively with facts. The abortion debate continues to rage because at its core is a personal choice of value – the mother’s biological freedom vs the life of a fetus. In the population debate there are value judgments regarding humanity’s rights and responsibilities toward the earth and all other life on it.
A recent issue of New Scientist explores various points of view regarding the population debate. For anyone interested in this topic this makes for good fodder. The basic facts are this – human population is now reaching 7 billion people. It is estimated that by 2050 we will exceed 9 billion. However it is also true that as our technology progresses we are able to sustain more people with fewer resources.
It often seems, therefore, that where one stands with regard to the population issue depends upon whether one is a pessimist or optimist. Although, even for the maximal optimist it must be acknowledged that there must be some upper limit to what population the earth can comfortably support, and that at some point (despite technological advances) increasing population becomes an increasing drag on the environment and other species – for reasons of physical space if nothing else (setting aside expanding the human population off planet and focusing just on the population of the earth).
Taking the pessimistic point of view is Paul and Anne Ehrlich, who write:
Somehow, cultural attitudes toward large families everywhere need to be changed. It should be considered immoral to have excessive numbers of children – an attitude that already exists in most industrialised nations with low birth rates. Nothing is more clearly a governmental responsibility than keeping a nation’s population size sustainable by benevolent measures.
As well as curbing population growth, we shouldn’t forget the pressing issue of excessive consumption by the rich.
Their argument amounts to a peak resources position – it will get more and more difficult to sustain an increasing population with fewer and fewer resources. Again, this is likely to be true at some point, but saying that we are essentially there now seems to ignore the role of technological advance.
Staking out the other end of the spectrum is Jesse Ausubel who points out that while the population has been increasing at a rate of about 1% per year, crop yields have been increasing at a rate of 2% per year, allowing us to grow more food on less land. In this interview he says:
Technology has liberated humans from the environment. Today we live about equally well in polar and tropical, arid and wet environments. The new question is whether humanity can use technology to liberate the environment itself. E-books, landless agriculture – farming that uses very little land because of high yields – and subterranean maglevs show the way.
It is important to note, however, that even a techno-optimist like Ausubel points out that we need to prioritize those technologies that do “free nature” by allowing us to do more with less. He is not saying that we should ignore the issues of population and resources – but that we can rely upon technological advances to give us solutions, if we choose to use them.
Conclusion
I admit I am more toward the Ausubel end of the spectrum than the Ehrlich end. Doom and gloom predictions over the last century about population increase and dwindling resources have not come true. Reading the Ehrlich’s warning about rising death rates sound a lot like the predictions of massive die offs that have been made and failed to manifest on a regular basis over the previous decades.
At this point I think we can conclude that it is not terribly useful to make predictions based upon current sustainability, because technology is constantly changing the equation. And technological advance has continued to surprise us. It seems likely that in 100 years the problems humanity will be facing are likely to be different than most of those causing current worry.
This does not mean, however, that we should just shrug and not worry. Thoughtfully contemplating the implications of our industry and population, and how to prioritize technological development and research is likely to have a huge impact on our future. I am optimistic that technology will give us potential solutions to the problems caused by a rising population within finite resources.
But we still need to develop and implement those solutions. Some of them will happen as a matter of course – people will use light bulbs that use less electricity and last longer simply because they will save money. But others may require more deliberate application, and we may need to bridge to “better” technologies through a cost-ineffective transition. For example, we may need to subsidize solar energy against the very cost effective fossil fuels before fossil fuel prices surge because of scarcity.
I say “may” because I personally don’t know – this is a specific technical question best left to appropriate experts. An approach I generally recommend over ideology.
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24 Responses to “The Overpopulation Hubbub”
One focus is the narrow question of whether X billion people could physically survive on Earth and keep a decent standard of living. I am more worried about the species and ecosystems that will not survive this survival, that have not survived human population growth. That’s not a prediction, but an observation of what has already happened.
In other words, while we could focus somewhat narrowly on the question of whether X billion people could live with a certain standard of living on our planet, that is not the only consideration people have when discussing human population growth. I understand why people get emotional about this–I sure hate it when I find out about species for which humans have been the midwife of extinction.
Because of what is happening now because of population growth (and standard of living elevation in resource rich but poor countries), it would be good to limit population growth. At the same time we need technology to improve standard of living while minimizing negative impact on the environment.
I remember as an undergrad a professor actually said ‘Science created the problem, so there is no way science will help solve it.’ He thought we should get back to hunter-gatherer type societies. Some of the more idealistic hippy students ate such ideas up. It was silly. On the other hand, we can’t turn a cold shoulder to the destruction that has already been visited upon the environment as a result of our species’ expansion. Until we have the technology in place to limit such destruction, I would agree that having a zillion kids is unethical for most couples.
I wouldn’t support government restrictions on fecundity, of course, but a little education about observed present-day consequences would be good.
For a Sci-Fi spin on this topic, take a listen to “The Kindness of Strangers” by Nancy Kress. The last 10 minutes of the story are of particular relevance. http://escapepod.org/2009/09/24/ep217-the-kindness-of-strangers/
Hi Steve,
I wonder if the quote you gave from the Erlichs was from their book Ecoscience? The reason I ask is that there has been a storm of controversy about this book because it was co-authored by John Holdren who is the science and technology advisor to the President. Apparently they mention in the book several ways that the US government could legally and covertly control the population such as puting sterilizing agents in public water supplies. They also mention the concept of forced abortions and other such eyebrow-raising topics. I have not been able to find this book, but it seems as though they are hypothesising about what to do in the event of an overpopulation worst-case scenario. Would you mind putting your two cents in on how you view Holdren in his new position, as well as what some of the skeptical community at large may have to say about these extreme answers to over-population?
I’ll include a couple of links to sites that talk about Holdren. They are all clearly biased against him, but some of what they quote him as saying sound pretty implausible to have been merely taken out of context (especially a comment that he made during his confirmation stating that he believed it possible for 1 billion people to have died from global warming by 2020).
Article from February 2009 – http://www.frontpagemag.com/readArticle.aspx?ARTID=34198
Blog from July 2009 – http://zombietime.com/john_holdren/
It is a completely wrong idea that hunter gatherers have a lower environmental impact. Per person hunter gatherers have a gigantic environmental impact. It is just that their environmental impact is spread out over a large area so it looks small.
People living in cities have the lowest environmental impact. They live vertically so little wildlife habitat was destroyed for living space, water is gathered from remote places and conveyed mostly by gravity, waste water is collected, treated and discharged. Food is grown at high yields with soil nutrients being replaced by fertilizers. Close proximity reduces transportation energy use. Buildings sharing walls/roofs/floors reduce heat/cooling loads. Heat and power is generated in large efficient boilers with pollution control equipment.
Although there are limits imposed on population growth by physical space and availability of resources, the more important questions revolve around quality of life. Significant changes in lifestyle will be imposed on us long before we reach any hard limits. Water resources, for example, are already a major concern for people living in the western U.S. If you like a green lawn, be prepared to pay a huge financial cost for this luxury. My point is that we don’t need to start running out of food before major changes in lifestyle are forced on us. Keep in mind that Americans in particular don’t like giving things up. We are a very spoiled nation.
The real question is what lifestyle we want to have and when will resource depletion begin to impact that lifestyle. These are voluntary decisions that we as a civilization can make. We could choose to have a trillion people running a muck on the planet, but what life would that be (regardless of technological advance)? Check out the original Star Trek episode “The Mark of Gideon” for a geeks perspective.
I don’t think forced population control will be the answer at any point in the near future, but I do essentially agree with the Ehrlichs that altering peoples attitudes about family size will be important to maintaining good balance.
Thanks Steve,
Jim Stunkel
The economy is a complex system. The world ecology is a complex system.
Why are so many people so positive that the function of one complex system will save us from the vagaries of the other complex system? The market is not completely rational. It can not be counted on and societies have wiped themselves out before. Read Collapse by Jared Diamond.
It seems to me that we are aware that a cliff exists. The cliff represented by resource and or ecological depletion. We are walking but we don’t know our speed or direction. Are we walking towards or away from the cliff? Are we walking or running?
In this situation I would not start running. I would walk forward slowly testing the ground as I go. I would probably get a cane; A long long cane.
I mean the economy is not a FULLY rational system and one should not put full faith in it.
I think decision markets are good things
From the biases of my armchair position, I see human population growth much the same as I see global warming, as a problem causing situation that should be ideally curbed to avoid a multitude of complex and somewhat unforeseeable issues in the health and welfare of humans, ecosystems, and economies.
As previously mentioned by Queequeg, I would highly recommend reading Collapse by Jared Diamond. The book provides examples of how – generally isolated – societies, when faced with ecological, resource, and population issues, either succeeded or failed due to the decisions they made. The societies presented in his book may not necessarily apply to our increasingly global society, where a wealth of resources from one area may serve to aid an area lacking such resources. Yet, they prove to be instructive guides to the fact that, regardless of being intelligent and innovative, we may not necessarily solve any issue we, or nature, imposes upon is in adequate time to avoid societal and population collapses.
We’re no shorter on space for people than we are on space for landfills, though our minds might not think so when posed with astronomical numbers we can’t really conceptualize. When a region struggles to support it’s population with the resources it can produce, they slowly approach a balance until improvements are made to shift the position of balance.
The aspect of what impact on our planet is acceptable is the big controversial question, and all the little choices we make each day like what we consume, how much we consume, how much we conserve and reuse, or even how many kids we have, state our position in that debate. Though we’re not usually thinking about it when we make those choices.
Although it may be technologically possible to support a larger and larger human population, what do we gain by doing so? Is a planet with 9 billion people better than one with 3 billion?
The current population receives much of its support from the unsustainable use of resources like fossil fuels or fish stocks or aquifers. Such use may have the effect of eventually lowering the human carrying capacity of the planet.
No doubt the population will adjust itself to decreasing resources. But such “adjustments” — disease, famine, warfare — are viewed by most of us as rather ghastly and something we would rather avoid.
“However it is also true that as our technology progresses we are able to sustain more people with fewer resources.”
I don’t think this is true. Technology allows us to support more people, but I haven’t heard that per-capita resource consumption in the developed world is going down. If you have data t to the contrary I’d love to see it. The last I heard energy consumption (one of our more vital resources) is still going up in the U.S..
While it is true that the conclusions of the _Population Bomb_ overreached, but the logic is undeniable. At a given level of technology the earth has a carrying capacity. Expecting technology to keep pace with population growth is more than wishful thinking. The fact that we can’t calculate the carrying capacity makes the concept all the more alarming. If we focused on both population control and technological improvement we would gain way more breathing room.
Like global climate change most people are happy to not think about this issue or to dismiss it with an easy rationalization because it allows inaction on their part.
There were two points made early that I think may have been glossed over, or perhaps not appreciated for what they actually mean: It is mentioned that human population is growing by 1%, and that our food capacity is growing by 2%. Some people may see the former as driving the latter, but it is probably better to view the issue (and I say “issue” and not “problem”) from the other direction. Increases in food supply (and other resources) drive population growth, and not the other way around.
The fact that the human population continues to grow indicates that there is in fact room to grow, at least in the short term. Certainly individual procreation may appear to be a private decision involving only two individuals, but there are these larger forces that drive this. People have kids if the resources exist to support those kids, either personally or within social safety nets.
That’s the first answer to the first question: Human populations continue to grow precisely because there is room, in the short term, for continued growth.
Now, there’s a second issue that gets ignored here, which is that overpopulation is also a local problem, not just a global one. America does not have an overpopulation problem, although you could argue that some areas in the SouthWest are outgrowing their water supply, but by and large we do not have an overpopulation problem. Even China does not necessarily have an overpopulation problem. They have a large population, and they have lots of overcrowding, but they also have the resources and economic growth to sustain such a population (although god help us all if China experiences an economic collapse, as it would make the Great Depression look like an average day on Wall St).
But no, what I mean about local overpopulation refers to various areas in Africa and in other areas of the world where we have what are euphemistically called “developing nations.” Many countries in Africa experience famine, sometimes on a semi-regular basis. Why does this happen? Because in those locations, the population actually has outstripped its resources. To some extent, this has less to do with the population itself and more to do with inept leadership that has failed to provide the infrastructure and resources necessary to support the population, at least in some situations.
So if you were to ask someone in America about overpopulation, you might get one answer. Ask someone in China, you may get a different answer. Ask someone in Sudan, or Somalia, or Liberia, or Nigeria, and you will get a very different answer indeed.
In the end, though, and I hate to make this sound all Zen (I blame the large doses of anticonvulsants, sorry), but it is not a question of what size population can this planet support, but what size of a population can humans support on this planet.
And the consequences of overpopulation, it bears mentioning, may not be as acutely dire as many predict. Rather than mass die-offs, which are certainly possible, what is far more likely to happen is that if population growth slows or drops precipitously, we will find ourselves in a situation with a greying, elderly-oriented population, with a much smaller group of productive workers. Bad news for the elderly, since they will have less support…but certainly better than the alternative. I don’t think that I need to go into detail as to why the opposite, a predominantly younger population, is truly dangerous.
davew – we use more energy because we do more, we raise our standard of living. But technology allows us to increase the efficiency of what we do. We grow more food on less land, for example. We light rooms with less energy. Our manufacturing processes are much more efficient, etc.
We cannot predict the future. All we can say is that so far technology has kept pace with populations increases, and the dire predictions of the past have not come to pass.
But, as I clearly stated, this cannot last forever. We will have to reach an equilibrium point at some time. But we have no idea what the carrying capacity of the earth is. I do think that those who are now predicting some major collapse at 9 billion are probably way off, as they have been in the past.
The quality of life issue is probably more relevant. We have to figure out what we want to do, not just what we can do.
I’d argue that knowing the equilibrium point is important. A basic predator-prey model will predict that the predator population will overshoot the equilibrium point, rapidly deplete the prey population followed by the death of the predator population that can no longer be sustained. It then can take sometime before the prey population to recover to re-support a growing predator population. There are many variations to this model but they all build off this simple closed system.
If you draw the black box around the Earth (I’d say globalization makes this a legitimate boundary condition), humans could possibly overshoot the equilibrium point of sustainability and the quality of life will suffer immensely until the food supply can support a growing human population once again. Knowing where the equilibrium point is is then important to avoid overshooting it.
Global climate change may artificially destabilize the system. The US Defense Department has invested resources into studying this problem. http://www.nytimes.com/2009/08/09/science/earth/09climate.html
davew, In some areas per capita resource consumption is going down. If we think about the resources to supply a phone, a cell phone takes a lot fewer resources than the land lines of 50 years ago. There are no miles of copper wire supported by giant dead trees treated with creosote connecting large masses of bakelite, iron cores and copper windings with relays and switchboards in a central station manned by operators. The per capita resources to supply a phone are less via cell phone technology than via land line technology. The cost should be less too, but that is the problem with monopoly pricing.
Many developing regions are avoiding the land line step altogether and going straight to cell phones.
Many technological devices are cheaper, in real terms, than they have ever been. A car that is lighter uses fewer pounds of iron, copper, and rubber. Modern manufacturing processes take less labor because of the efficiencies of scale.
I think the real danger is in the prevention of the adoption of new technologies for non-scientific reasons, for example GMO plants have the potential to greatly increase food production and sustainability. Chemical fertilizers do too. Nuclear power can produce electricity without green house gases. Higher MPG cars could have been reducing gasoline consumption for years, but big cars had more profit than small cars.
A world with 9 billion people is better than a world with 3 billion people. The 6 billion people that are alive in the first one who are not alive in the second one would tell you it is better. Of course the 3 billion in the 3 billion world would say that it is better because each of them “owns” 1/(3 billion) of the world instead of 1/(9 billion), and people who don’t exist (either because they haven’t been born or have been killed) don’t get a voice.
@daedalus2u “In some areas per capita resource consumption is going down.”
I agree with this and I agree with Steve’s points about technology allowing for more efficient living. At Steve also pointed out, however, this has led mostly to an increase in standard of living. Yes we can feed more people per acre of land, but at a truly remarkable level of energy consumption and waste of both topsoil and the poisoning of our aquifers and oceans. When you look at aggregate, per-capita resource consumption, as well as such a thing can be estimated, we are still going up and a few Priuses and CFL bulbs don’t change the equation significantly.
“A world with 9 billion people is better than a world with 3 billion people. ”
I don’t know how to quantify this. A world with 3 billion people makes it much easier to deal with resource issues than 9 billion people. Then again we don’t know how to run an economy with a declining population. I am not so much a starry-eyed idealist that I don’t understand that this too is a serious problem, but one we’ll have to solve eventually. Maybe Japan and eastern Europe will provide a model.
(If you think dead people don’t vote, you’ve never lived in Chicago.
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One thing people miss when talking about mass die-offs is that they do happen and they are happening. The sole cause will never be overpopulation or resource depletion. It’s not like a million people are going to cry “molybdenum”, grasp their chests and fall over in unison. Nor are die-offs global. They are in discrete areas and a result of many causes including disease, drought, war, and bad government. Population itself is rarely a problem, but it makes most other problems much harder to deal with.
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My suggestion would be to get the U.S. Government to stop subsidizing children in proportion to the number you have. I think it should be the inverse. For one kid or maybe two you get a tax break and free education up through college. The third is on you and perhaps some of the benefits for the first two start going away. I know this would never fly in this country politically, but a boy can dream.
I recently read a story of a rancher here in Colorado that is switching to all “organic” naturally grazed beef. To do this, he has to lower the number of cattle he owns to allow more space for grazing. Despite this, his profit margins will increase, since people are willing to pay more for organic foods. This isn’t the first time I’ve heard this, many farmers are converting to organic and eliminating the fertilizers and pesticides that allow for higher yield crops. I’ve often wondered, is this obsession with organic meats and produce moving in the wrong direction to support an increasing population?
I was reading this today, and it reminded me that as we push technology forward to allow more people to live on the planet, there are other potential disasters on the horizon as a side effect.
JG, yes I think it is the wrong direction. Too me, eating organic food is just like driving a Hummer or cutting down a rain forest. It wastefully uses land that could otherwise be used for wildlife habitat.
davew, I think your understanding of agriculture is mistaken. What plants need to grow is inorganic nutrients, water, light, air with CO2 and a porous substrate. Use of chemical fertilizers need not cause water pollution through run-off, and run-off from organically fertilized farms can be just as polluting as from conventional farms. Some of the largest fish kills have been from the spilling of manure into rivers. There isn’t enough organic fertilizer to meet the needs of agriculture.
Our greatest resource is the minds of creative people. Right now, many of those minds are being wasted because they are stunted from a lack of food, lack of health care, lack of education, lack of access to good governance, lack of access to safe living conditions, lack of resources to achieve their potential.
Some of you mentioned how population growth doesn’t necessarily present a problem in developed nations like the US, but I didn’t see anybody make the point that there are actually countries that are suffering from the opposite problem.
I currently live in Japan, where population DECREASE is an everyday concern. They frequently talk about koureika and shoushika over here, which mean “age increase” and “child decrease” respectively. Even Tokyo’s population is expected to decrease after peaking in about 2010. In the city I live in, some elementary schools that were built for hundreds of children now hold ten or less. Fertile farmland sometimes goes unused. There are also a great deal of societal problems that that come with the population decrease in terms of medicine, welfare, mental health, etc. Basically the population distribution pyramid is upside down, and soon the retired population will be larger than the working population.
Ironically this does little to alleviate the population increase of other nations, as Japan doesn’t want to open its doors to foreign workers. There was recently a push to “take back” Japanese-Brazilians and other ethnic Japanese as laborers. But now many of these workers that came just a few years ago are being offered money by the government to go back to their home countries, as jobs are scarce in Japan in the current economy. Numerous issues related to population decrease were also paramount in the recent election, which lead to the first change in the leading political party in decades.
I guess just as deflation can be as economically damaging as crippling inflation or stagflation, population decrease can be just as complicated a problem as excessive increase. I can’t offer a unique solution to either problem, but I do feel like the current situation in Japan and other developed countries suggests an alternative scene on the planet’s horizon compared to pure, indefinite geometric expansion or a typical “predator/prey” model.
@davew “Use of chemical fertilizers need not cause water pollution through run-off, and run-off from organically fertilized farms can be just as polluting as from conventional farms.”
This sentence is very spun. While chemical fertilizer “need not” run off it does. While organic farms “can be” as polluting as conventional, they aren’t. Not by a miles. My garden, and for that matter the organic farm down the street, fertilize with composted organics from our own properties. I’m no more polluting than a field or a forest.
As to what can and cannot be done the world is a very complex case. I guess there is plenty of land in the U.S. to feed our population with organically-raised food if we were all vegetarians.
I’m much more toward the pessimistic end of the spectrum. Part of this is simply a personality difference, and there’s nothing much to say about it. The other part rests on three observations:
- There are strong signs that human activity is seriously degrading environmental resources.
- Psychologically, the warnings of the seventies seem to have led to overconfidence. Once we’d gotten to the nineties and the warnings hadn’t materialized, the warnings seemed to be discredited. In environmental sciences as in financial bubbles, those who can see danger coming usually can’t time the crash. I suspect Ehrlich was not so much wrong as just 50 years early.
- Technologies mature. Technology is subject to the law of diminishing returns, just like everything else. Going from 20% efficiency to 60% efficiency is a lot easier than going from 90% efficiency to 99% efficiency.
@jaycm
Well said.
My speculation is that humans are not wired to solve problems like this. I hope I’m proved wrong, but I don’t see many signs of hope yet.
This is a great reason for space habitation research.
Making a miniature environment to sustain some humans while taking precise measurements of resource cycles would give a good start for working at larger planetary scales.
Also, the carrying capacity has an upper bound around 14 people per square meter perpendicular to the sun, assuming a 2000 calorie per day diet per person and 1366 watts per square meter of energy from the sun and perfect conversion from solar energy to life sustenance.
I leave finding a more useful number up to someone else.