33 ms·

Earth's population isn't growing exponentially or even linearly, though.

pyre 17y ago
Source? Numbers? I know that a few first-world countries like Japan have negative population growth, but is that the case everywhere? Are the countries that having negative population growth enough to offset those with positive?
- warfangle 17y ago
  http://www.wolframalpha.com/input/?i=world+population http://www.wolframalpha.com/input/?i=world+population Population growth world-wide is 1.14% per year.
  - electromagnetic 17y ago
    Actually on a long enough scale population growth is exponential and has been increasing at a phenomenal rate (by such time scales). However the good news is that the time it takes for the world population to double is estimated to increase. (Ed, note that any growth on any scale can be read as exponential. On a geological scale the human population growth is akin to the big-bang, but on a daily scale it's equivalent to a lethargic snail.) This is due to the fact that if current trends continue, it will have taken 12.3 years for the world population to go up by a billion (however it should be noted, earlier estimates -1990 IIRC- suggested it should have hit 10 billion ~2012), which is a mild increase over the last billion of 12.25 years. I believe the next billions are expected to take 13, 15 and then IIRC 18 years. There's many relevant factors effecting population growth. Many of the diseases that plagued our ancestors are almost completely cured in the west (I've never heard of someone dying from a broken arm, however 200 years ago it was a prominent risk). We also have food preservation techniques that no one had before. Everywhere from penicillium being used in meats to prevent bacterial growth to refrigeration, vacuum sealing, freeze drying and even vacuum freezing (where the moisture is literally sucked out of food, meaning it can last unrefrigerated for up to 10 years). There's also irradiation techniques that, given proper storage, can enable food to last indefinitely. There are also vast misconceptions about over population that plague these discussions. For example, China is less densely populated than the UK and Japan, yet has food struggles because they don't have the economy to import food on mass. Many African countries plague by starvation are desolate compared to most countries, yet neighbouring countries have populations almost one hundred times as populated (note that this even applies in the landlocked countries interior and isn't a comparison between a country with a large ocean border and one with no border).
    - jacobolus 17y ago
      > Actually on a long enough scale population growth is exponential This doesn't really make sense. Human population growth could potentially be modeled as a logistic curve, but I doubt that even really explains or will explain things adequately. More realistically, human population growth without new technology or social structures showing up is exponential, but those dramatically change its shape, to the point I'm not sure we can predict population more than 2-3 decades out.
- neeson 17y ago
  http://esa.un.org/unpp/ http://esa.un.org/unpp/
- gojomo 17y ago
  http://en.wikipedia.org/wiki/Population_growth#Human_population_growth_rate http://en.wikipedia.org/wiki/Population_growth#Human_populat... From a peak growth rate of 2.2% on a base of 3.2 billion in 1962-1963, the world population growth rate declined to 1.2% on a base of 6.6 billion in 2007. That's about 79 million net new people in 2007. Wikipedia elsewhere reports that 1989 was the year with the largest absolute increase in population, 87.8 million net new people. So shrughes' report of not-even-linear growth seems true, at least for the last 20 years.
- philwelch 17y ago
  Most first-world countries have zero or negative population growth when you don't account for immigration. This seems to be a result of economic development. Most countries are also economically developing over time so you can expect the population growth rate to peak and decline as this happens. It has happened, in fact. Of course, this development is dependent upon the presence of natural resources which may interfere with the food supply (i.e. biodiesel or ethanol fuels).
ivankirigin 17y ago
And shrinking in richer economies. You can't extrapolate out decades with those kinds of trends. Lots of developing economies will be as rich as the west is today before then.
Periodic 17y ago
Isn't it a law in ecology that a population will grow to the limit of its scarcest resource? In some countries that is food, in many modern societies now it seems to be time. We know that the population can't grow exponentially forever, but other than a recent dip in fertility rates, we have seen a fairly steady exponential growth. http://www.iiasa.ac.at/Research/LUC/Papers/gkh1/chap1.htm http://www.iiasa.ac.at/Research/LUC/Papers/gkh1/chap1.htm
- tokenadult 17y ago
  Isn't it a law in ecology that a population will grow to the limit of its scarcest resource? Who says so? Why would an observation that may (or may not) apply to bacteria or even to wolves apply to human beings?
  - roc 17y ago
    It strikes me as more of a tautology. If a population stops growing, then clearly it's because it has run out of some resource, particularly if you go so far as to include things such as 'time' as a resource.
    - Periodic 17y ago
      I think it is used more to predict how a system will respond to a change in resources. If you reduce the amount of resources available to a population, that population will shrink approximately proportionally (until there is enough for the rest to survive), and if you increase the resources the population will grow to use those resources reasonably quickly. It also points out that it is the scarcest resource that limits growth. Increasing food will not allow the population grow if there isn't enough water, sun, etc. My point was mostly to point out that we may have some other scarcity that isn't food which is limiting the growth rate in industrialized countries, while increasing the food in starving countries will just cause the population to grow until it hits the limit of some other resource. I suspect that it isn't any sort of time scarcity that is limiting current human growth, but more likely the impact of contraceptives messing with our normal biological mechanisms.
  - 17y ago

pyre 17y ago

Source? Numbers? I know that a few first-world countries like Japan have negative population growth, but is that the case everywhere? Are the countries that having negative population growth enough to offset those with positive?

warfangle 17y ago
http://www.wolframalpha.com/input/?i=world+population http://www.wolframalpha.com/input/?i=world+population Population growth world-wide is 1.14% per year.
- electromagnetic 17y ago
  Actually on a long enough scale population growth is exponential and has been increasing at a phenomenal rate (by such time scales). However the good news is that the time it takes for the world population to double is estimated to increase. (Ed, note that any growth on any scale can be read as exponential. On a geological scale the human population growth is akin to the big-bang, but on a daily scale it's equivalent to a lethargic snail.) This is due to the fact that if current trends continue, it will have taken 12.3 years for the world population to go up by a billion (however it should be noted, earlier estimates -1990 IIRC- suggested it should have hit 10 billion ~2012), which is a mild increase over the last billion of 12.25 years. I believe the next billions are expected to take 13, 15 and then IIRC 18 years. There's many relevant factors effecting population growth. Many of the diseases that plagued our ancestors are almost completely cured in the west (I've never heard of someone dying from a broken arm, however 200 years ago it was a prominent risk). We also have food preservation techniques that no one had before. Everywhere from penicillium being used in meats to prevent bacterial growth to refrigeration, vacuum sealing, freeze drying and even vacuum freezing (where the moisture is literally sucked out of food, meaning it can last unrefrigerated for up to 10 years). There's also irradiation techniques that, given proper storage, can enable food to last indefinitely. There are also vast misconceptions about over population that plague these discussions. For example, China is less densely populated than the UK and Japan, yet has food struggles because they don't have the economy to import food on mass. Many African countries plague by starvation are desolate compared to most countries, yet neighbouring countries have populations almost one hundred times as populated (note that this even applies in the landlocked countries interior and isn't a comparison between a country with a large ocean border and one with no border).
  - jacobolus 17y ago
    > Actually on a long enough scale population growth is exponential This doesn't really make sense. Human population growth could potentially be modeled as a logistic curve, but I doubt that even really explains or will explain things adequately. More realistically, human population growth without new technology or social structures showing up is exponential, but those dramatically change its shape, to the point I'm not sure we can predict population more than 2-3 decades out.
neeson 17y ago
http://esa.un.org/unpp/ http://esa.un.org/unpp/
gojomo 17y ago
http://en.wikipedia.org/wiki/Population_growth#Human_population_growth_rate http://en.wikipedia.org/wiki/Population_growth#Human_populat... From a peak growth rate of 2.2% on a base of 3.2 billion in 1962-1963, the world population growth rate declined to 1.2% on a base of 6.6 billion in 2007. That's about 79 million net new people in 2007. Wikipedia elsewhere reports that 1989 was the year with the largest absolute increase in population, 87.8 million net new people. So shrughes' report of not-even-linear growth seems true, at least for the last 20 years.
philwelch 17y ago
Most first-world countries have zero or negative population growth when you don't account for immigration. This seems to be a result of economic development. Most countries are also economically developing over time so you can expect the population growth rate to peak and decline as this happens. It has happened, in fact. Of course, this development is dependent upon the presence of natural resources which may interfere with the food supply (i.e. biodiesel or ethanol fuels).

ivankirigin 17y ago

And shrinking in richer economies. You can't extrapolate out decades with those kinds of trends. Lots of developing economies will be as rich as the west is today before then.

Periodic 17y ago

Isn't it a law in ecology that a population will grow to the limit of its scarcest resource? In some countries that is food, in many modern societies now it seems to be time. We know that the population can't grow exponentially forever, but other than a recent dip in fertility rates, we have seen a fairly steady exponential growth. http://www.iiasa.ac.at/Research/LUC/Papers/gkh1/chap1.htm http://www.iiasa.ac.at/Research/LUC/Papers/gkh1/chap1.htm

tokenadult 17y ago
Isn't it a law in ecology that a population will grow to the limit of its scarcest resource? Who says so? Why would an observation that may (or may not) apply to bacteria or even to wolves apply to human beings?
- roc 17y ago
  It strikes me as more of a tautology. If a population stops growing, then clearly it's because it has run out of some resource, particularly if you go so far as to include things such as 'time' as a resource.
  - Periodic 17y ago
    I think it is used more to predict how a system will respond to a change in resources. If you reduce the amount of resources available to a population, that population will shrink approximately proportionally (until there is enough for the rest to survive), and if you increase the resources the population will grow to use those resources reasonably quickly. It also points out that it is the scarcest resource that limits growth. Increasing food will not allow the population grow if there isn't enough water, sun, etc. My point was mostly to point out that we may have some other scarcity that isn't food which is limiting the growth rate in industrialized countries, while increasing the food in starving countries will just cause the population to grow until it hits the limit of some other resource. I suspect that it isn't any sort of time scarcity that is limiting current human growth, but more likely the impact of contraceptives messing with our normal biological mechanisms.
- 17y ago