Four Surprising Facts About Population

Why Humans Are Not Fated to Ecological Disaster

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One often hears that we are in the midst of exponential population growth, and that the Earth cannot support many more people. But what is really going on with global population trends? In this essay, we present four surprising facts that will change the way you think about population, the environment, and human progress.

March 19, 2014 | Marian Swain,

One often hears that we are in the midst of exponential population growth, and that the Earth cannot support many more people. Unless we take immediate measures to control population growth, the story goes, we are on a crash course for ecological and humanitarian disaster.

But what is really going on with global population trends? In this essay, we present four surprising facts that will change the way you think about population, the environment, and human progress.

1. The global population is likely to peak and decline in the 21st century

The world population is still growing, but the rate at which it is growing has actually been decreasing ever since its peak in the 1960s. Currently the world population is growing at about 1.2 percent per year. 

FIGURE 1.

Source: UN data


We are already experiencing a slowdown in population growth, and it is expected to continue in the coming decades. The UN’s median scenario projects flat or decreasing population size in all regions except Africa. Other projections suggest that the global population may even peak this century. IIASA, an Austrian scientific research institute, estimates there is an 85 percent chance that the world’s population will stop growing before the end of the 21st century (Lutz et al. 2001), and its median scenario sees population actually starting to shrink around 2070 (see Figure 2) (IIASA 2007).

FIGURE 2. Total population of the world, in billions


Source: IIASA


2. We are continuously increasing the Earth’s carrying capacity

It is sometimes suggested that there are hard biological limits to how much food the Earth can produce, but ever since the invention of agriculture 10,000 years ago humans have been consistently increasing yields through the use of new technologies. Indeed, it has been increasing yields that have allowed the human population to grow to its current population of seven billion. In this sense, the Earth’s carrying capacity is not bound by a finite set of planetary boundaries, but rather is a function of human technology.

FIGURE 3.


United Nations Food and Agriculture Organization, FAOSTAT data

 

3. To combat climate change, technology is more important than population

Population is undoubtedly a factor in anthropogenic climate change, since it is human activities that create greenhouse gas emissions. But a far larger factor than population is the kind of energy being used. One billion people on the planet getting electricity from coal would create more carbon emissions than 6 billion people each getting the same amount of electricity from solar or nuclear power (see Figure 4).

FIGURE 4.


Sources: IPCC for solar and nuclear; Nakicenovic et al 1998 for gas, coal and wood. 


4. Decreasing fertility goes hand-in-hand with human development

Fertility (the average number of children a woman gives birth to in her life) is closely correlated with development. The countries with the highest fertility rates are generally the poorest ones, while almost all the richest countries have fertility rates that are actually below the replacement rate of 2.1 children per woman.

The realities of poverty make large families a rational choice. Without access to healthcare and sanitation, child mortality is high and women need to have more children to achieve a desired family size (Gates). Without access to social security systems, having lots of children is a form of insurance (Bulatao, p. 4). But when families gain access to modern services like healthcare, education, and social security, fertility rates start to fall, since it becomes practical for women to choose smaller family sizes (National Research Council, p. 93). There is even evidence that exposure to modern media like television can create downward pressure on family size.

Using per-capita income as a proxy indicator for overall human development, we can see a clear correlation between fertility and development. The charts below from Gapminder.org show that as incomes around the world have increased between 1910 and 2010, fertility rates have fallen dramatically. In the developing world, people are increasingly moving to cities, gaining access to modern services, and the fertility rates of these countries have, in turn, been falling.

FIGURE 5. Fertility rate versus income per person, 1910 and 2010


Source: Gapminder

This is not to say that we should not do anything to promote lower birth rates; increasing access to contraception in the developing world is an important goal for governments and development NGOs, both to enable effective family planning and to increase female autonomy. However, access to contraception is only one of many factors that affect women’s fertility choices. Broader issues of poverty and education are also crucial to address if we hope to encourage women to choose smaller family sizes. 

 

Marian Swain is a Conservation and Development Policy Analyst at the Breakthrough Institute. 

 

Photo Credit: Straitstimes.com


Comments

  • We long ago exceeded the earth’s carrying capacity for our species. The means to extract calories from the agricultural lands we currently use are unsustainable - will not be available to us much longer - dependent as they are on cheap energy and fertilizers, pesticides that work, a stable climate and plenty of water.  Full exploitation of the cheap fossil energy supply we depend on GUARANTEES that we will lose the stable climate and water we need.  Since you made no mention of calories from the sea, I feel it is necessary to point out that this hugely important food source is on the verge of collapse. You are whistling in the dark

    By Bill Copeland on 2014 03 23

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    • We long ago exceeded the earth’s carrying capacity for our species. The means to extract calories from the agricultural lands we currently use are unsustainable - will not be available to us much longer - dependent as they are on cheap energy and fertilizers, pesticides that work, a stable climate and plenty of water.  Full exploitation of the cheap fossil energy supply we depend on GUARANTEES that we will lose the stable climate and water we need.  Since you made no mention of calories from the sea, I feel it is necessary to point out that this hugely important food source is on the verge of collapse. You are whistling in the dark

      Poster Bill Copeland is - and there are few polite ways to put this - an alarmist idiot.

      If we had exceeded the Earth’s carrying capacity for our species, death due to obesity would not be higher than death due to starvation. Yet it is.

      The means to ‘extract calories from the agricultural lands we use’ are also not unsustainable. Newer farming practices and the use of fertilizer prevent this from being so. Drip irrigation technology means that we could reduce agricultural water usage by more than 80% if farmers would just adopt the technology.

      If environmentalists would stop whining about it, the West could switch to clean nuclear power - such cheap, clean thorium reactors - and significantly reduce our reliance on fossil fuels for electrical production. Demand for fossil fuels would lower significantly and allow supplies to last much longer at a far lower usage rate.

      Sustainable fishing practices can insure that ocean stocks continue to survive, as will fish farming.

      I’m not even going to get refuting the ridiculous idea that climate change is at risk of being catastrophic.

      The fact of the matter is that there are numerous solutions to these rather small problems, but environmentalists don’t care; to them, humans are a disease that must be wiped out. Strange how they never volunteer to go first.

      By Yehudi Roman on 2014 03 24

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      • nuclear energy? don’t go by the charts. it is one of deadliest technology out there and probability of it being deadliest is exactly 1. and it’s carbon footprint is pretty large too - include mining costs, and costs to maintain reactors long after it is silent… about 2500 years.! I bet libtards like you do read. but then I know. you don’t.

        By ray1 on 2014 04 06

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        • From your post, it looks as though you are unaware of different possible nuclear reactor types and are probably familiar only with the mediocre pressurized water uranium reactors which are now being used because of bad decisions.

          Before commenting on nuclear power, I suggest that you spend at least 40 hours studying alternative reactor types.  In fact, it is possible to use thorium instead of uranium.

          I really cannot blame people for being ill informed about nuclear power since the media have made no effort to inform people adequately.

          By Frank Eggers on 2015 06 21

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          • i am aware of the thorium process, and that it was as well-known decades ago as the processes/designs which were selected for construction back in the 50s and 60s. and we know how well those have been working - or not.

            i am sure i have spent at least 40 hours studying reactor types, tho not much recently as those hours were in college engineering classes. i also worked for MHB.

            but really, the grasping at straws for some kind of energy source to replace the fossil fuels we are addicted to must be a sign of un/conscious desperation. fear of hardship and death are a motivation practically guaranteed to sabotage good science, which requires a detached perspective.

            science is about trying to understand the world for its own sake, not yours. it’s about having a great wild and cool idea about how the world works, and then trying to make yourself wrong. if you can’t do that, you might likely be right, as least some of the time.

            so the grasping after a thorium magic bullet reminds me of the thrive movement movie: http://www.youtube.com/watch?v=lEV5AFFcZ-s

            and my problem with these two hypotheses about magic energy solutions is that until we figure out how to manage the problem of the ‘dominator culture,’ the domineering, hierarchical, patriarchal, centralized, authoritarian culture that we are all somewhat infected with, no magic energy source will avail us to solve the problems you are hoping thorium will.

            By Muriel Strand, P.E. on 2015 06 24

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            • What about Pebble Bed tech for nuclear?
              As I understand those, making sources into pebbles, coated with [clay?], they make easily controlled reaction, and, with small pebbles, a melt-down is almost impossible, because if one or two melt-down, the others won’t. 
              Less source is needed than with rods, less building materials, drastically less waste.  The whole thing runs cooler. 
              Less sources, less heat, far less melt-down factor, and smaller reactors, less waste…what’s not to like?  And they can be small enough to run a building.  Far less adverse impact on environment.
              So, why aren’t we doing THOSE?

              By Chimonger on 2015 06 24

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              • By Muriel Strand, P.E. on 2015 06 24

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                • The argument that nuclear power is dependent on fossil fuels makes no sense.

                  It should be obvious that constructing solar and wind farms also requires fossil fuels.  Both require many times as much concrete and steel as nuclear plants require.

                  The argument that uranium is a finite resource also makes no sense for several reasons:

                  1)  It ignores the fact that our current less than mediocre nuclear technology and fuel cycle extracts less than 1% of the available energy from the mined uranium and that better uranium technologies, which could extract almost 99% of the energy from the mined uranium, would drastically reduce the amount of uranium required and the amount of nuclear waste.  In fact, better nuclear technologies could use our current nuclear “waste” as fuel thereby getting rid of most of it.

                  2)  It ignores the fact that uranium can be extracted from sea water.  With the greatly reduced uranium requirements that would result from a better nuclear technology, extracting uranium from sea water would make economic sense once all the easily mined uranium has been mined.  That would not occur for centuries with a more efficient reactor technology.

                  3)  It also ignores that fact that uranium is not needed for nuclear power; thorium, which is is three or four times more abundant, can be used instead.  Moreover, because thorium occurs with rare earth elements and is discarded as waste, already enough thorium has already been mined to last for centuries.

                  One of the problems is our media.  The media fail to educate people adequately about nuclear power the result being that most people are not well informed.

                  By Frank Eggers on 2015 06 25

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              • I don’t know enough about pebble bed reactors to comment on them intelligently.  Therefore I will not do what many commenters do, i.e., condemn them without having sufficient knowledge to have a valid opinion.  However, if they look promising, surely they should be explored.

                By Frank Eggers on 2015 06 25

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  • I am probably wasting my time with this, but first let me agree with you on nuclear power. We are going to need it and GMOs too, no argument there.
    I will not concede the carrying capacity argument to you though, as we are way out on an overshoot limb right now.  You could call that alarming but we all know that “alarmist” is a code word used by “denialists”, so you are not scoring points there.  I will leave it to other readers to decide what to think about the intelligence behind the rest of your choice of words.

    The high obesity rate is a perfect example of how unsustainable our food system is.  The Secretary of Agriculture under Nixon, Earl Butz, got us started on our current unhealthy path when he decided that food needed to be cheaper and implemented sweeping changes in farm policies that have produced our calorie-rich and nutrient poor American diet. Every package of junk food cereal and twinkies is fortified with vitamins, so why do we have a problem?  Our food system has failed to sustain us in a healthy way because of its intensity and monotony. We are exporting this model to the Third World and - surprise! -  they are getting diabetes.  So, sure, we can keep the cheap unhealthy calories flowing for awhile yet with industrial agriculture and its high inputs of pumped groundwater, fertilizer (causing dead zones in the great lakes and the Gulf of Mexico) and pesticides, but the system will be very sensitive to disruption and failure as the climate changes. Drip agriculture works great in dry climates until it creates salinized soil toxic to plants, so it is unsustainable.

    There is no major fishery on earth right now that is sustainable, not even most (though not all - and I do like catfish) aquaculture.  The ocean “fish farms” depend on feed stocks that are themselves unsustainable and they concentrate and spread disease. The shrimp farms destroy mangrove forests and also concentrate and exacerbate disease problems.  Model systems such as the Barramundi Closed system aquaculture have promise but are very expensive, will never feed the many.

    The quality of human life on earth has been degraded in proportion to the harm we have done to the environment, which is where we live. Should we really be arguing bitterly about protecting it for the next generation?  Should we really be unwilling to acknowledge how terribly serious this is?  You apparently have no idea to what lengths environmentalists will go to protect the earth.  Keep watching.

    By Bill Copeland on 2014 03 24

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    • If anyone disagrees that we have too many people on this planet, go to India, China, and see what that many people has done to the earth, and the quality of life. I just returned from teaching and living in India, and I can tell you first hand, I agree with Bill Copeland.

      By Harvey Thornhart on 2014 04 06

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  • Obesity happens with excess calories from numerous causes:
    1. Nature coerces human animals to seek foods with nutrients we must have—almost entirely subconsciously. 
    IF we can’t find the right foods, we consume rabidly those that have the appearance, in any way, of the ones we must have…eating those calories to excess, desperately trying to get those nutrients.
    2. Due to human creativity and greed, the number / variety of fake foods—those that LOOK like what we need, but lack the properties, abound, wrapped in flavors we learn to prefer; turning us away from eating actual healthy foods—educating by taste preference, instead of functional palate education towards healthy, nutritious foods.
    3. Prices for actual nutrient-replete foods is high—ask most on tight budget why they avoid fresh produce, they say it’s too costly.
    Food Banks don’t stock fresh produce much, either. 
    Cost is not only for the produce, but the energy needed to store it properly and its limited shelf-life.  quires knowing how to eat it, and, learning to like those flavors from the time we first learn to chew food.
    4. Emotional eating has drastically increased, as overall quality of life has gotten far more stressful; the rift between rich and poor has become an ocean, etc. Stress-eating is epic.
    WHY has no one done anything about this?

    By Chimonger on 2014 03 26

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  • Narrow thinking, bandaid solutions, failing to consider the “Big Picture”, have brought us to where we are…on a precipice.
    GMO’s as we know them, are drastically unsustainable in so many ways.
    Nuclear power, as we know it, is drastically unsustainable—the waste from it, alone, is harming us and many generations hence.
    There ARE better solutions, but certain Industries have fallen into a trap of their own making: profiteering, a tasty drug, has driven those to steadily increase profits—at any collateral cost or damage.  Those have too often worked maliciously to block or destroy whatever solutions they didn’t utterly control, and push legislation to protect themselves from anyone criticizing or trying to get reparations for damages caused by them.
    Your article fails to address real nature, real conditions.
    When we try too hard to divorce ourselves from nature—and believing humans can over-populate so glaringly, is that—-we are destined for problems insurmountable in our lifetimes. 
    NO OTHER creatures are allowed to massively, indiscriminately, over-populate, and all come out alive; when species do, it’s a signal preceding disaster—they do it anticipating only some will survive coming hard times.  OTHER animals naturally populate relative to living conditions, limiting populations naturally.
    ONLY humans fail to do that.  We artificially keep people alive, artificially feed bad calories, etc., wrapped up in some very weird/sick psychology/sociology/religiosity trying to justify our actions and beliefs—-damn the torpedoes, full speed ahead!?. 
    THINK beyond your lifetimes x 7, at least, when planning to implement yet another high-tech bandaid solution! 
    It’s not just your survival or your children’s survival—it’s survival for far longer, that is affected by whatever is done now. 
    Consider how the proposed solution will affect all organisms we share the planet with. It’s about Balance, Sustainability, Quality of life for all species, not just Humans.

     

    By Chimonger on 2014 03 26

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  • You wrote, “Nuclear power, as we know it, is drastically unsustainable—the waste from it, alone, is harming us and many generations hence.”

    You have not indicated an awareness of better nuclear technologies which, through R & D, could be prepared for implementation to solve the problems associated with out current nuclear technology, i.e., the pressurized water reactor using uranium for fuel.  Thus, I cannot tell whether you are aware that better nuclear technologies are possible.  Although our current nuclear technology is a bad technology, it is still better than the alternatives.  “Renewable” systems are intermittent and do not provide reliable power.  Coal emits both toxic substances and huge amounts of CO2.  As demand for power greatly increases to permit poor countries to lift their people out of poverty, we must use nuclear power.

    Unfortunately, R & D on nuclear power was virtually halted which is why we are temporarily stuck with a bad nuclear technology.  Better nuclear technologies can solve the problems associated with our pressurized water reactors which use uranium for fuel.

    I am reminded of environmentalists who, a few decades ago, advocated doing away with refrigeration because CFCs were damaging the ozone layer.  Had they been better informed, they would have known that we had refrigeration way before CFC were invented and that CFCs were not essential for refrigeration.  Now I see the same thing happening with those opposing nuclear power; they are uninformed about other nuclear technologies.

    By F. R. Eggers on 2014 03 31

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  • it seems that the people who think humanity can do anything will never admit that maybe humanity can’t do everything.

    it seems that some economists believe in infinite growth and substitutability. but physicists don’t agree: http://physics.ucsd.edu/do-the-math/2012/04/economist-meets-physicist/

    and just because population might stop growing so fast doesn’t mean we haven’t already exceeded carrying capacity: http://www.booktv.org/Program/15516/2014+Tucson+Festival+of+Books+Alan+Weisman+Countdown+Our+Last+Best+Hope+for+a+Future+on+Earth.aspx

    By Muriel Strand, P.E. on 2014 03 31

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    • We have exceeded carrying capacity UNLESS we use different technologies.

      We can probably design crops which fix their own nitrogen thereby eliminating the need to use nitrogen fertilizer for many crops.  Advanced nuclear power, which would be safer and less expensive, can make it possible to desalinate large amounts of water thereby solving the problem of water shortages.  It can also make it more economical and more environmentally friendly to produce nitrogen fertilizers for the crops which still require it.

      Evidence in several countries indicates that with prosperity, fertility decreases and is likely to lead to a reduction in population without enacting oppressive laws.

      By Frank Eggers on 2014 04 01

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      • nature has already designed crops that fix their own nitrogen. in general, wisdom counsels technologies that are friendly to biology - and particularly botany. but nuclear, like fossil fuels and toxic agriculture, ain’t friendly.

        By Muriel Strand, P.E. on 2014 04 06

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  • Would that the title of this essay were the Truth.

    Unfortunately, what the author has failed to take into consideration is that, incredibly, it is in the ‘business interests’ of Judaeo-Christianity-Islamism, Inc. to incite a genocidal war in the Middle East (to *prove* the Truth of their own specific theologies)—referred to as “Armageddon” or the “time of trouble” Prophesied by Daniel; while it is in the ‘business interests’ of the media to preserve the ‘business interests’ of these religious officials.

    Michael

    By Michael on 2014 04 06

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  • I know the peeps reading this are all in a same mind-frame.. as with all media sources now-days. But I just wish to be the fly on the wall as you try to justify your position to your grand children after the effects of this kind of rationalization finally touches the lives of you and yours.. Oh yea.. and dont forget to mention that radiation is good for you .. just another ann coulter wanabe..

    By reality King on 2014 04 06

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  • One blast from the Sun and it’s all over for humans here on earth… All, or a large percentage, of the nuclear power stations will melt down…. and it WILL happen. Not to mention Fukushima, which alone will damage the world and generations for a LONG time to come.

    Greed, selfishness, pride… the “me first and the gimme gimme” reptiles with their reptilian-dominant brain choices will ruin the world. They’re just sooo speecial.
    And Einstein was such a brilliant lizard.

    By Chris on 2014 04 06

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  • Unfortunately, much of the world’s wealth has been squandered in senseless wars.  The problem with population is that the wrong people have the most children.  It would be humane to pay people NOT to have children, rather tan paying them to have them, which is what we do now,

    By John Hendricks on 2014 04 07

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  • One reason that people have too many children is that they see it as necessary to provide for themselves in old age.  When there are adequate social safety nets, they are less likely to have so many children.

    The world’s normal state since prehistoric times has been war.  I have a theory that if people had always been sensible, kind, and peaceful, we’d have by now advanced at least 1,000 years ahead of where we are.

    By Frank Eggers on 2014 04 07

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  • The population is growing at almost the same rate, just the percentage is lowering because there is more of us, and two percent of seventy billion would be lower than, say, sixty-nine billion. And I agree with Frank Eggers. If we didn’t have a need to fight and kill and dominate we’d have gone a lot further.

    By Olivia on 2015 07 29

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    • This. We’ve had just slightly greater than linear growth for the last 4-5 decades of 80m pa and 12-14 years per billion added. Plot this on a normal graph and it’s a straight line. Calculate it as a percentage growth rate number added / total and that growth rate falls.

      Prior to about 1970 global population was growing exponentially. Since then it has grown linearly. The open question is how long that linear growth continues and if and when it transitions to zero or falling growth. And critically, is that transition a nice gentle change or the kind of Seneca Cliff drop off predicted by some models.

      By Julian Bond on 2016 03 09

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