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I'm looking at a chart of world population from 10,000 BCE to modern times. It appears the world population rate rose sharply somewhere around the 1700's (and maybe a tad bit earlier):

The size of the world population over the last 12,000 years

I'm confused because it is earlier then expected (as I understand things). First, efficient fertilizer production did not occur until the early 1900s, so food production was mostly constant (confer, Haber process). Second, preventative and curative medicine is rather modern and seems to be dated somewhere after the 1800's, and penicillin debuted the early 1900's (confer, History of medicine).

What caused the increase in world population rate around 1700's?

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    Potatoes and beans, mostly :)
    – rs.29
    Sep 8 '19 at 7:18
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    One cannot draw any conclusion about "start point" of the exponential growth from a linear plot. Unless plotted as semi-log, the choice of "start point" for the exponential growth is entirely dependent on the plotter's choice of vertical scale. May 2 at 12:21
  • Guano islands were discovered in the 1840s which predate modern nitrate fertilizers. Secondly the industrialization during the 1700s produced machines that could plow deeper and faster bringing much more land into productivity. Finally you are only looking at food productivity and ignoring other factors that lead to large populations like increased access to health care, decreased infant mortality rates, and things like modern medicine theory. It wasnt just more births, it was people were living longer than ever before.
    – ed.hank
    May 2 at 17:50
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The general pattern of rapid population growth seen in early modern Europe around the 1800s (and to a more limited extent in the 1700s) is known as "stage two" of the demographic transition. Quoting from Wikipedia:

This stage leads to a fall in death rates and an increase in population.The changes leading to this stage in Europe were initiated in the Agricultural Revolution of the eighteenth century and were initially quite slow. [...]

The decline in the death rate is due initially to two factors:

  • First, improvements in the food supply brought about by higher yields in agricultural practices and better transportation reduce death due to starvation and lack of water. Agricultural improvements included crop rotation, selective breeding, and seed drill technology.

  • Second, significant improvements in public health reduce mortality, particularly in childhood. These are not so many medical breakthroughs (Europe passed through stage two before the advances of the mid-twentieth century, although there was significant medical progress in the nineteenth century, such as the development of vaccination) as they are improvements in water supply, sewerage, food handling, and general personal hygiene following from growing scientific knowledge of the causes of disease and the improved education and social status of mothers.

A consequence of the decline in mortality in Stage Two is an increasingly rapid growth in population growth (a.k.a. "population explosion") as the gap between deaths and births grows wider and wider. Note that this growth is not due to an increase in fertility (or birth rates) but to a decline in deaths. This change in population occurred in north-western Europe during the nineteenth century due to the Industrial Revolution.

Europe was the first region to experience such a transition. A similar pattern spread to other parts of the world, on an increasingly rapid scale as various technologies were introduced into the twentieth century.

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    I'm disappointed not to see mention of how misleading a linear vertical axis is for all such growth graphs. Unless plotted as a semi-log, the choice of "start point" for the exponential growth is entirely dependent on the plotter's choice of vertical scale. May 2 at 12:20
  • I don't agree that a linear scale is "misleading" but it's true that a different chart can better illustrate the importance of the earlier agricultural revolution.
    – Brian Z
    May 4 at 0:04
  • A linear scale can only show absolute growth clearly. A semi-log chart shows rate of growth instead of absolute growth. It's an implicit assumption in both the question and your answer that the linear display is showing rate of growth. That's simply false. May 4 at 6:28
  • The demographic transition is real, not an artifact of illustrating it with a linear scale. The entirely unprecedented population growth rates in modern times can still be seen clearly (although not as dramatically) on a log scale.
    – Brian Z
    May 5 at 11:56
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I can't give a cause for the population growth up to 1800, and the numbers are pretty much guesswork anyway, but I have a favourite theory about the cause of the exponential increase after 1800. I can even give you the month when the cause occurred. It was a Sunday (we don't know which one) in May 1765 when James Watt realized how to build an efficient reciprocating steam engine, which initially facilitated much cheaper exploitation of minerals and subsequently enabled industry to break free from the limitations of water power.

Industrialisation is what caused the prosperity which in turn enabled the two things upon which population growth has depended. First, the technologies and social organisation which reduced death from disease, particularly in infancy. Second, the production of food and basic necessities for a growing population. It all started on a sunny May day in Glasgow, in 1765, and the whole thing has depended up until about now on the exploitation of abundant fossil fuels.

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  • Using the definite article "the" in the phrase "the cause" isn't plausible for something like this. I doubt that there was a fundamental change to population growth which commenced on a Sunday in May 1765. May 2 at 11:57
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    As noted above, and above: One simply cannot draw any conclusion about "start point" of the exponential growth from a linear plot. Unless plotted as semi-log, the choice of "start point" for the exponential growth is entirely dependent on the plotter's choice of vertical scale. May 2 at 12:22

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