Overpopulation and Standard of Living #3


Pregnant Pause Home Overpopulation


Does overpopulation lead to poverty? The conventional wisdom is that a crowded country must inevitably be poor, because they just won't have the resources to support all the people. They won't be able to produce enough oil, metals, wood, etc, to sustain the economy. If they're crowded enough, they won't even have enough food and fresh water for everyone.

So let's test this conventional wisdom. The CIA World Fact Book lists pretty much every country in the world with a mass of statistics about each. Conveniently for our purposes here, it includes the population and total land area, from which we can easily calculate population density, and the per capita income. The CIA converts foreign currencies to US dollars by relative purchasing power, that is, how many Euros or rubles or whatever does it take to buy the same amount of "stuff" that you could buy with US$1.

So I drew the following graph, showing population density along the horizontal access and per capita income on the horizontal access, and then plotting a dot for each country in the world.

Population Density (people per square km) vs Per Capita Income (equivalent US$)

(Sorry, your browser must support HTML5 and Javascript to display the graph.)

Well, blast. That doesn't make a very readable graph, because there are a handful of countries with very high population densities that push all the rest far to the left -- Hong Kong, Singapore, Macau, Monaco, etc. So okay, here's the graph redrawn with a log scale. For the mathematically inclined, that meens that the spacing of numbers along the x-axis is proportional to the logarithm of the value rather than being linear. For the less mathematically inclined, it means we stretch out the smaller numbers and bunch together the bigger numbers. :-)

Population Density (people per square km) vs Per Capita Income (equivalent US$)
(Density as log scale)

(Sorry, your browser must support HTML5 and Javascript to display the graph.)

Yes, there are points all over the place. This shouldn't be much of a surprise: surely people with widely varying opinions about overpopulation would agree that population density is not the only factor affecting a country's prosperity. Nevertheless, if the "overpopulation theory" is correct, we'd expect the general trend of all these points to be from upper left to lower right. That is, countries with low population densities should be relatively rich, while countries with high population densities should be poor.

But ... On both graphs, the light green line is the least-squares approximation. This is a standard statistical tool: the straight line that has the minimum total distance to all the points. (It doesn't look like a straight line on the log plot because of the "bunching".) The trend is quite distinctly upward as we move to the right. That is, if we look at actual countries in real life, the more densely populated a country is, the richer it tends to be, not the poorer.

Of course there are exceptions, but in general, the richest countries are densely populated, and the poorest countries are sparsely populated.

How could this be?

Well first let me say that it doesn't matter if I have a theory to explain it. The facts, the experimental evidence, are that more people means more prosperity for everyone. It doesn't matter if we understand why. People got hurt when they fell off a tall cliff, even before the theory of gravity was understood!

But I can suggst two possible reasons.

One: Specialization. If you concentrate on doing what you're good at, and let other people concentrate on what they're good at, and then share the results, everyone will be better off than if each had tried to do a little bit of everything. For example, suppose that you're very good at repairing cars, and your neighbor is very good at gardening. Meanwhile, your neighbor can't figure out how to open the hood, and you can't grow dandelions. If you and your neighbor could work out an agreement where you'd repair his car in exchange for him taking care of your garden, you would both be better off. Get more people and more skills involved and making all these trades quickly gets out of hand, so today we usually use money rather than trying to arrange individual deals, but money is just a handy way to store human labor.

The more people there are, the more it is possible to specialize. This can lead to drudgery, of course, like the classic picture of the factory worker who spends his whole life screwing in the third bolt on the left hand door. But if done right it means people can spend their time doing things they're good at, and most of us prefer to do things were good at than to do things we suck at.

Two: New ideas. People come up with new ideas, better ways to do things, new inventions. The more people there are, the more new and better ideas will be generated. Unlike material things, like cars or loaves of bread or whatever, it costs nothing to make a copy of an idea. (Well, it costs something to spread an idea, the cost of printing a book or broadcasting a TV program or whatever. But it costs very little.) Whether there are a thousand people in our society or a million, it costs little more for all of us to use one new idea. But the more people we have, the more new ideas we'll have. So societies with more people get more new ideas, but it doesn't cost more to spread them.

Photo © Seaonweb | Dreamstime.com - Hong Kong City At Night Photo


Pregnant Pause Home Overpopulation

Posted February 5, 2017

Copyright ©2017 by Pregnant Pause
Contact Us