Population and limits: Have we exceeded earth's carrying capacity for an industrialized humanity? And if so, to what extent?
Randolph Femmer
Friday, 13 February 2009 01:54 UTC
In the 1960s and 1970s it was commonly imagined that earth’s human population might be limited by supplies of food and/or similar critical resources.
While such concerns are real and important (and are intuitively obvious), the intervening decades suggest that our industrial and societal wastes (such as a half-pound or more of CO2 released, on average, with each mile that we drive – not to mention all the other CO2 generated in our workplaces and home and by society at large), along with the physical damage that we have inflicted and are inflicting on earth’s ecosystems and biological machinery, may already portend a disconcerting assemblage of humanitarian, environmental, and civilizational disasters already, right now, and in the four decades between now and midcentury.
We have climbed from less than two billion people inhabiting our planet just one hundred years ago to approximately 6.8 billion people today, with billions number seven, eight, and nine on-track to arrive between now and mid-century, which are numbers that we may come to regret. Resource: The Open-Space Delusion
Updated 13 February 2009 02:01 UTC
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Replies
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“Have we exceeded earth’s carrying capacity for an industrialized humanity?”
Absolutely. I am amazed, in fact, at how slow many, even in the scientific community, have been to figure this out. I finally had to write a pair of essays to demonstrate it with simple logic:
Essay #1 : This one proves quite simply that we have overshot carrying capacity given today’s levels of per capita resource consumption.
Essay #2 :This one uses ecological footprint data to show that no remotely realistic reduction in per capita consumption, without also attending to our numbers, would be enough to bring us down out of overshoot.
That second essay stops short, though, of really indicating how deeply into overshoot we are. A couple of simple considerations make this clear, though they do not “prove” it.
First, consider that for virtually all of human history our numbers never exceeded 5 to 10 million. So we evolved and were stable at numbers of a few million. Post-agriculture our numbers gradually (over almost 10k years) rose to 1 billion. Then in less than 200 years they exploded by another 6 billion. That explosion happened in less than an eye blink of human history. Is it even remotely reasonable to assume this would not spell serious problems for ecosystems worldwide??
Second, many still toss around the old notion that our technologies have increased human carrying capacity. But consider our complete reliance on limited fossil fuels to drive industrial agriculture. This is what William Catton calls “phantom carrying capacity.” It’s not carrying capacity at all; it degrades our habitat and is unsustainable.
No, we have not so much increased carrying capacity as we have learned, at increasing peril to ourselves and millions of other species, how to overshoot it.
I could go on at length, but I hope that is enough to spark some thinking and investigation of this crucial issue.
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“The ostrich, buries his head in the sand”
The problem with the world population (numbers of human beings) is that there is nothing anyone can do about it. Certain religions promote high per-capita reproduction. A woman recently had 13, or was it 15 children. A great fuss was made of this on TV. She was considered a phenomenal person. A great mother! And so we go. The fact is that the world human population is the only population on the planet that has increased exponentially for over 1000 years. This truism seems to have escaped most of us. We go on as though nothing is happening. Even those who know better bury their heads in the sand, for what can they do? Malthus, who saw the problem over 200 years ago (even if he got the timing wrong), is considered by many (who do not understand exponential growth) as a lunatic. Human beings, like any other participant in the struggle for existence, are approaching their end. They are just not clever enough to avoid it. C’est la vie!
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OVERPOPULATION
John M Reid
Introduction
Climate Change and Overpopulation are the two problems that threaten the future of life on Earth. The two problems intersect and are interactive, but they are separate and distinct, and either is sufficient to cause the Holocene Mass Extinction.Planet Earth is becoming warmer. This may be due solely to natural phenomena or there may be an anthropogenic contribution to the process, but it is almost certain the planet is undergoing a cyclical change in surface temperature and in climate. The regional distribution of hotter/cooler, wetter/drier areas is changing as part of the overall change in the climate. If the change is largely attributable to natural processes, it may be beyond the power of humans to do anything about it, except, perhaps, to stop pouring accelerant on the fire.
Overpopulation is not a ‘natural’ process: It is an artefact, the outcome of human behaviour. We caused the problem, we can solve it. Unfortunately, it is inherent in the collective mindset of our species that most people avoid even thinking about the problem, let alone acting to try to solve it.
What is the justification for saying there are too many human beings on Earth? It comes down to simple arithmetic. The capacity of the Earth to provide the resources we need to sustain us—that is, the arable land, grazing land, forests, fisheries, potable water, fossil fuels—and the means to dispose of the waste we generate is limited. How many people the Planet can support depends primarily on how much ‘bioresource’ each of us consumes. The Planet is not a Magic Pudding that is continually replenished as it’s eaten; it is more like a can of ice-cream—if everyone has a one-scoop cone it can supply, say, 100 people, but if every customer demands a two-scoop cone it can only supply 50 people. And this is the trade-off: the more people, the less bioresource available for each person, and conversely, the fewer people the higher each person’s sustainable level of consumption.
Before we come to the discussion of how many people the Planet can support at a reasonable level of consumption, I need to explain some of the terms used, and to say where the data relating to the capacity of the Planet come from.
The total capacity of Planet Earth to sustain life , which is referred to as its ‘biocapacity’ in the Living Planet Report (LPR) 2008, is expressed as billions of ‘global hectares’ (Ggha). The LPRs are published biennially by The Global Footprint Network (GFN): The most recent of these, LPR 2008, is based on 2005 data. The methodolgy by which LPRs are prepared is scientifically sound, and they provide the data used by a number of soverign states in formulating their environmental policies.GFN is supported by 77 ‘Sponsoring Partners’, 8 ‘Endorsing Partners’, and about 58 ‘Participating Partners’. The partners include the equivalents of state and local governments, NGOs, universities, and private environmental consultants. GFN commissions studies by its partners and provides stringent Footprint Standards and Guidelines covering the methods for collection of information for Footprint Studies (Kitzes, et al., 2007; www.footprintstandards.org)
In 2005, the biocapacity of the Earth was 13.6 Ggha, and the population was 6.5 billions; therefore, the sustainable per capita global footprint was 2.1 gha. But aggregate demand was for 17.5 Ggha, which represents a per capita demand of 2.7 gha.In other words, in 2005 we were overdrawing the bioresource account by about 29% per annum.
Since 2005, the world population has increased to approximately 6.8 billions and the demand for resources from developing economies, such as China, India, Brazil, and Indonesia has increased substantially—in China, the Beijing Olympic Games alone must have generated a large increase in demand. On the supply side of the ledger, the biocapacity of the Planet has, if anything, been reduced as the result of ongoing land degradation, forest destruction, and fish stock depletion. Consequently, at a conservative estimate, demand now exceeds supply by something like 35–40%.According to the UN’s most-likely, medium growth scenario (UN 2004), by 2050 the population of the World is projected to have increased to at least 9.1 billions, although it is understood this figure is likely to be revised upwards. Some would suggest the 2050 population will be nearer 9.5–10 billions.
Table 1 World populations in 2007 and 2050 (est., UN medium-growth-rate scenario) by income groups (LPR 2008). No allowance is made for redistribution of populations, such as low-income countries becoming middle-income countries by 2050, nor for migration of people from low-income countries to higher-income countries. (x million)Populations 2007
Rich Countries 942
Medium-Income 3085
Low-Income 2452
World 6479Populations 2050
Rich Countries 1025
Medium-income 4277
Low-Income 3765
World 9067Source: 2007 data CIA World Factbook 2008 from which 2050 data calculated. Note minor variations from UN 2006 Revision of Population Database.
Demand
In the light of the current World financial situation, the IMF has reduced its forecast for World economic growth in 2009 to 1% (IMF, February 2009). On the other hand, China’s and India’s growth rates are likely to remain relatively high, say 7-9% and they account for more than a third of the World’s population. Even if the World’s population growth rate was zero, an economic growth rate of 3% would mean by 2020 we would be consuming over 3.8 gha/person, which is 1.8 times the biocapacity of the planet.In relation to food shortages, there is a line of argument that says the main problem is one of maldistribution, rather than shortage of supply. Although this argument is simplistic—for example, usually people who support this argument do not take into account food staple preferences (e.g., rice vs wheat), the intolerance of certain foods by some genotypes (e.g., lactose intolerance), and ‘stickiness’ in the supply chain—it is partly true. We in the rich countries will have to drastically reduce our demand, although this will not necessarily then ensure an adequate supply to areas where there are food shortages.
Table 2 shows the 2005 demand in global hectares per capita for each of the 3 income group, plus USA, Australia, and the EU, and the sustainable level of demand.
Table 2. Average global footprint (i.e., demand) in gha/person in rich countries, middle-income countries, low-income countries, and in USA, Australia, and European Union (EU), and sustainable demand in 2005
Rich 6.4
Middle-Income 2.2
Low-Income 1.0
USA 9.4
Australia 7.8
EU 4.7
Sustainable 2.1Source: LPR 2008
The average Australian footprint is 4th highest of all the countries included in LPR 2008; it is exceeded only by United Arab Emirates (9.5 gha/person), USA, and Kuwait (8.9 gha/person).
Today, in Australia, the main concern by conservationists is energy consumption and the production of greenhouse gases from fossil-fuelled power stations and transport vehicles, but even if Australia converted immediately to using exclusively alternative, renewable-energy sources, and stopped exporting coal and liquified natural gas, Australians would still be consuming 5.82 gha/person, about 2.8 times the sustainable consumption. (The comparable consumption figure for the USA is 2.9 gha/p.). However, if Australians also stopped eating exotic grazing animals and growing wool, and stopped cutting down the forests, they could be living sustainably, consuming just 2.1 gha per person.
How likely are politicians, not just in Australia, but throughout the rich countries, to be prepared to tell their electorates economic growth is out of fashion, and that the new ‘growth’ is back to hunter-gather subsistence living? I find it inconceivable that any of our present politicians would be so courageous (as Sir Humphrey Appleby might have put it) as to say this, even if they believed it to be true.
Of course, even if the Rich countries could be persuaded to freeze growth and maintain their present levels of demand, China’s consumption has been growing at between 9–11% per annum, and India’s at about 9% per annum. Although China is likely to suffer a slowdown in its growth as a result of the present world financial crisis and the recession in its export markets in USA and Europe, it will only be a temporary setback.
Probably, India and China will not be able to maintain their present economic growth rates through to 2050, but both certainly aspire to achieve standards of living comparable to those of, say, European Union economies (approximately 4.7 gha/person). Taking population growth into account, in 2050 the demand from India and China will be for about 16 Ggha.
No doubt the populations in the other middle-income countries, then about 877 million people, will also expect to achieve a similar standard of living, so the aggregate demand from this group will be for about 20 Ggha.
Similarly, the low-income countries will expect to raise their present standards of living to, say, the present level of middle-income countries—2.2 gha/person. Consequently, their aggregate demand in 2050 will be for about 8.2 Ggha.
If rich countries were to accept a no-growth economic regime, their demand would be for about 6.6 Ggha.
Under these assumptions, total World demand in 2050 will be for about 34.8 Ggha, which represents the biocapacity of more than 2.6 Planet Earths. This is obviously not a feasible scenario, even in the very-short term. In fact, even if nothing changed, the present overconsumption (1.3 x the biocapacity of the Planet) cannot continue. Business as usual is not an option.
And bear in mind, these data make no allowance for wildlife species that have the misfortune to need to share the arable land, forest, and fishing grounds we use.
A Sustainable Population
As I said earlier, the number of people the Earth can support depends on the amount of bioresources each person demands. Please note, I did not say the amount of bioresources each person needs. If we had to live as hunter/gatherers no doubt some or, perhaps, many people would adapt to that level of consumption, but I doubt if many of us would enjoy such a lifestyle.Let us take Australia as an exemplar of the living standards people might expect to enjoy; but then suppose Australia could halve its carbon footprint so that the total footprint per person dropped from 7.8 gha to 6.8 gha. In 2005, the total biocapacity of the Planet was 13.6 Ggha, so in these circumstances the Planet could sustain a population of 2 billion people—less than one-third of the present World population — and, parenthetically, the population when I was a child!
Of course, this calculation makes no allowance for the effects of climate change on the World’s biocapacity. In aggregate, these effects can only be negative although some regions may become more productive.
Even the UN low-growth (unlikely) World population projection peaks at 7.4 billions in 2050 and gradually declines to 2.3 billions by the year 2300, but I doubt if we have 290 years grace in which to avert disaster. In fact, I suggest it is highly probable that by 2050 our demise will have become a very unpleasant, bloody process as mass migrations of people from inundated areas occur, and the starving billions slaughter each other for the last handfuls of rice.
Assuming climate change does not become so severe that the Holocene Mass Extinction kicks in (although I believe it has already begun), how can the World’s population be reduced by non-lethal, non-discriminatory means, quickly enough to avert disaster? Leaving aside contingencies such as Earth being struck by a large extraterrestrial body, or Toba errupts, the only means I can think of is universal contraception: And the only question then is, is contraception to be voluntary or involuntary?
I think most people who agree contraception is the answer say it must be voluntary. The World’s population must be persuaded of the need to practise contraception, and must be provided with the means to do so. These people say that educating and empowering women, and giving everyone a reasonable standard of living is the way to achieve voluntary contraception.
Unfortunately, there are counter-arguments that seem to me to be a lay-down mazaire.
Argument — Educate and Empower Women
Counter arguments
It doesn’t work — US fertility rates are increasing (Science 321 29 August 2008, p. 1139), and so are Australian fertility rates, which are already among the highest in developed societies. The women in both these societies are among the best educated with the highest standards of living.There is implacable religious hostility towards contraception, as Pope Benedict recently demonstrated. The three Abrahamic religions, Islam, Orthodox Jewry and Christianity are united in opposing contraception. One of the principal means all three use to exercise control over their adherents is by prescribing their sexual behaviour… or, as Churchill (or was it Gen. Patton?) remarked, “If you have them by the balls, their hearts and minds will follow”. They all proscribe artificial methods of birth control.
Having no children is not just a change of preference, it is a fundamental shift in the mindset, “It is the right of every woman/couple to reproduce and have as many children as they want…” In fact, this is stated in Articles 12 & 16 of the Universal Declaration of Human Rights.
So who would initiate and promote voluntary contraception? There are no signs politicians anywhere support universal birth control. In Japan, for example, women are being pressured to have children, and in Australia, financial incentives are provided to induce couples to procreate.
Generational change processes, such as this, take 25 years to begin to take effect, and then another generation is needed for the change to be fully implemented. By which time it will be too late: The Earth will already have a population of about 9 billions. We would then only be talking about the steepness of the die-away curve (see Fig. 1) — will it still take 290 years to reach a sustainable level?
There will be pressure to have children in order to replace population lost through war, famine and disease — and by extension, as voluntary reduction in birthrates begins to take hold in a proportion of the population, there will probably be a compensatory tendency (“equal and opposite reaction”) in the other proportion to increase family size — in the short run, leading to homeostasis.
Argument — Eliminate Poverty
Necessary conditions
First, there would need to be a change in the governments of most of the low-income countries. The corrupt élites that sequester the bulk of the income of most of the poor countries would have to be disempowered — not an easy task since often the military and the politicians are either one and the same, or are in collusion. All too often, we have seen how reluctant our politicians are to take even effective non-military measures against corrupt governments (e.g., Burma, Zimbabwe).Second, rich countries must pay market prices for the product of the poor, which is antithetic to ‘free-market’ capitalism (“Never give a sucker an even break” W.C. Fields). Rich countries must make long-term investments (NOT provide assistance via the ‘aid’ model) directly into poor countries without demanding a high return on their investment.
Health services (affordable pharmaceuticals, enough health profes¬sionals, hospitals and equipment, community health services, clean water, healthy living conditions, etc., etc.) must be made available.
Appropriate technologies (which adopt Schumacherian principles and are biosphere-friendly) must be used to provide transport and communications systems… other infrastructure, such as bridges, all-weather roads must be built. People’s banks for small business loans, and functional commercial banking systems must be set up.
An uncorrupted judical system must hold the ring.
Existing sovereign debt must be written off… and so on, and so on.
Are the rich countries likely to come to such an expensive party?
If voluntary birth control will not work, what about involuntary contraception?
The objections to enforced contraception are moral/ethical, and practical.Moral/Ethical Argument
People have the inalienable right to choose whether they have children or not, and to decide how many children they will have.Counter argument
If you are 99.9% sure voluntary contraception will achieve sufficient population decrease — remember, we are not talking about zero population growth, we are talking about reducing the population by two-thirds — AND you believe the rich- and middle-income countries will reduce their demand for bioresources to a sustainable level (≈ standard of living of average present-day Syrians) in time to save the Planet, then voluntary contraception is the way to go. If not, the survival of all life on Earth must have absolute priority over human constructs of moral/ethical behaviour.If theistic religions had any moral integrity, they would recognize that survival of God’s Creation (as they would say) transcends the right of any species to procreate to an extent that destroys the biosphere.
Practical Objections to Involuntary Contraception
How can you achieve involuntary contraception? By government edict? The Chinese government instituted a one-child policy in 1979. The policy is regarded as repugnant by many people both inside and outside China, and it is said to have led to unacceptable consequences, such as killing female children, and forced late-term abortions. In any case, the Chinese population is continuing to increase, albeit at a slower rate than that of most other emerging economies. To be effective, such a policy requires a political system that is free from corruption, has strong central control, and is not subject to judicial review. It is difficult to see how a one-child policy could stand against appeals to constitutional rights in countries such as USA and Australia.The alternative to mandatory contraception is biological, covert sterilization, and this is where moral objectors become most vociferous. But I say to moralists, if you are persuaded that the Planet cannot support the projected population, living at a reasonable standard of consumption, you must consider the alternative,
de-populate or perish.A word about politicians
I do not believe senior politicians in the developed-country governments are either innumerate or unable to recognize the impossibility of having both population growth and economic growth. This does not not mean most politicians necessarily accept the ‘strong’ version of the argument, namely that the World’s population must be reduced to about 2 billions, but I suspect many of them accept the ‘weak’ version, namely, that supply and demand for bioresources must be brought into balance.Unfortunately, politicians are not leaders when it comes to contentious issues; they sniff the mood of the electorate for the scent of political advantage, and sail downwind. At present, politicians the world over are not even saying we must forego economic growth, and they are supported by the Stern Report, the reports of the Intergovernmental Panel on Climate Change, and Australia’s Garnaud Report, inter al., that all say we can have economic growth provided we reduce greenhouse gas emissions. Even the Green political parties are not prepared to say, “We must have negative growth and we must drastically reduce the human population!”
Conclusions
It is a sobering and discomforting thought, but each and every one of us is a liability in the books of the Planet. Every single person, with the possible exception of desert Aborigines and other hunter/gatherers, departs this life leaving the Planet a bit poorer than when they arrived on it.Karshish, Melbourne, Australia
References
Central Intelligence Agency, 2008. World Factbook 2008. https://www.cia.gov/index.html
International Monetary Fund, 2008. World Economic Outlook Report, October 2008. http://www.imf.org/external/pubs/ft/weo/2008/02/index.htm
Kitzes, J., Peller, A., Goldfinger, S., & Wackernagel, M. 2007. Current methods for calculating national ecological footprint accounts. Science for Environment & Sustainable Society, 4.1, 1–9.
United Nations, 2004. World Population to 2300. UN Department of Economic and Social Affairs, Population Division.
WWF International, 2008. Living Planet Report, 2008. www.panda.orgP.S. NEWS: UK GOVERNMENT CAPS POPULATION GROWTH
18 October 2008: OPT welcomes the long overdue reversal of government pro-population growth policies. “This government isn’t going to allow the population to go up to 70 million… There has to be a balance between the number of people coming in and the number of people leaving,” new Immigration Minister Phil Woolas announced today in an interview with The Times. Mr Woolas was formerly Climate Change Minister. OPT has called for balanced [zero net] migration since 2003 and continues to campaign for UK population to be allowed to decrease to a long-term environmentally sustainable level. -
It is interesting to me that this web page has had no responses for over a month. I for one expected a huge reaction from scientists! Perhaps John Reid said it all, or perhaps my message was taken to heart? Is there really nothing we can do except accept the inevitable? Or does nobody (except a very few) even think about this problem? Are we really just going to die out and, perhaps though unlikely, take the rest of the world with us? It seems impossible that the Human race can really be as insignificant and uncaring as that? But that seems to be the case. Go on splitting genes and working the economy as we approach the end. It will all be wasted! What a shame that all of our great work will lie in the sand, unused and uncared about.
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Alan,
There is encouraging evidence that when a country gets serious about bringing down fertility rates it can be done:
Those examples don’t prove it but they do at least point to actions we might want to repeat elsewhere while collecting more data.
(Though I take John Reid’s point about educating women, it does seem generally to correlate with reduced fertility rates. It is at least something deserving further study. See this for example. And there is evidence that media strategies can effectively promote such education as well as much more widespread access to and use of family planning resources.)
I think the scientific community needs to wake up to this. In addition, the population issue didn’t just fade away 20 years ago; it was actively squelched by people with vested interests in making it go away. The real clincher was at the UN’s Cairo conference. See this report for info on that.
The scientific community needs to wake up to these points. Even if academics had a valid point that there may be little we can do about it, does that justify not even trying? What if they’re wrong? Aren’t the stakes to high not to try, not to go down fighting? At the very least, anything we can do to reduce fertility rate can help to soften the blow.
In short, I think what you heard from your academic friend is a rationalization. I think it has more to do with people not wanting to be attacked for speaking the truth and (in some cases) perhaps not knowing how to get the media’s attention.
That said, though I think there is much we could do, I am not overly optimistic we will. Few are willing to stick their necks out and be the one to speak up.
That was why I organized the Global Population Speak Out. I believe it was somewhat successful as there seems to have been an uptick in media coverage of the population issue in the last couple of months. (though perhaps that is due to some other factors… hard to tell) But some organization needs to repeat it on a much larger scale. As one individual with no funding I was able to get something like 100+ scientists and others to speak out publicly on the issue during February. A group with some resources should be able to get a thousand.
Incidentally, the more I have studied the issue, the more clear it is to me that we are far more deeply into overshoot of the earth’s carrying capacity for humans than most realize. I touched on this above but will add that once we made the transition to agriculture we immediately began disrupting and destroying habitat which is the basis for the web of life. We also began “mining” soil nutrients which are finite just like oil. So in a sense we went into overshoot 10k years ago. As the Sixth Mass Extinction has accelerated we’re now paying the price. When it comes right down to it, I do not think there is any solid evidence that human carrying capacity is much more than it was pre-agriculture — a few million. I’m not sure which bothers me more, the likely loss of civilization’s cultural contributions or the loss of all the other species we’re taking down with us.
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Interestingly, I went to a public lecture in Melbourne last evening. An historian from University of Melbourne and a water scientist from the Australian Conservation Foundation were talking about _Water Histories: Lessons for Australia in a Changing Climate _. Essentially, the theme was the need for better water management to alleviate the dire state of Australia’s Murray-Darling river system, with particular reference to the plight of small rural communities affected by the degradation of the system.
They managed to talk for an hour without once mentioning the problem of over-demand by too many people. It was implicit, we only needed to be better at managing the ecosystems to accommodate any number of people.
It was as if one was trying to solve an equation, but neglecting to take into account a major term of the equation.
When I made this point in the discussion following the lecture, and said the proposal by some politicians, economists, and business people to welcome an increase in the already-too-large Australian population from approx. 21 M to 45-50 M was living in cloud-cuckoo land, the Unimelb guy berated me, asking what was I going to do? Turn away all the millions of displaced persons and refugees who would want to come to Australia?… and in any case they would be coming here whether we liked it or not.
It occurs to me, someone should update C. P. Snow’s The Two Cultures to reflect the emergent ethos. It is no longer Science vs Arts, it is becoming Humanists vs Nature-comes-first-ists (Unfortunately, I can’t call us Naturists!) The guys last evening were putting the interests of human beings first; they were not prepared to contemplate reducing the human population, at least not by anything other than long-term gentle persuasion. On the other hand, I believe saving the biosphere must take priority over allowing unrestricted population growth.
I think many scientists who are quite prepared to innovate within their own laboratories are nervous about being seen as social deviants if they point out the simple arithmetic of too many people demanding too few resources, so they keep their heads below the parapet.
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I fear the people in possession of the awesome power that is being derived from the colossal scale and soon to become patently unsustainable growth of the global political economy are greed-mongering manipulators of democratic principles and practices who do not care about anything more than profits and accumulating material things. Their incorrigible idolatry of business-as-usual, wealth concentration, conspicuous consumption and unconscionable hoarding has reached so huge a scale and obscene a growth rate that the very future of the children is being put at risk. Perhaps necessary change toward the survival of offspring and sustainability, rather than the ruin of Earth as a fit place for human habitation, is in the offing.
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