Essay 21

Essay 21: Population Decline

When I was a youngster a half a century ago, one of the major concerns that people had was over population. Being a skeptic, I decided to figure out just how bad this problem might be. So, I did some calculations. Here is the math. If you don’t like math just skip over this paragraph. The key take-aways are in the paragraph following the math.

The land area of the entire United States is approximately 3.5 million square miles. A mile is 1760 yards, so a square mile is 1760x1760 = 3,097,600 square yards. We will round this off the 3 million to make the math a little easier. We have 3.5 million Square miles X 3 million square yards per square mile, so the land area of the US is 10,500,000,000,000 square yards. The population of the US is about 350 million. So, if we divide that into the land area, that is 30,000 square yards per person. There are 4840 square yards in an acre. So, dividing that into 30,000 square yards per person we get a little over 6 acres per person. It takes about 1 acre to feed a person, so each person has 5 acres left over for a swimming pool and a driveway.

There is about 6 acres of land per person and only 1 acre is needed to feed them. You might point out that you need public spaces, roads, parks, and the like. I would agree with that. But, much of the population lives in apartments in cities which have a high population density and much of the population outside of the cities lives on a quarter acre lot. So, the vast majority of people are not using their 6 acres.

Nonetheless, they are not making any more land, so if the population doubles then we will only have 3 acres per person and if it doubles again we will only have 1.5 acres per person. On the other hand, food production is getting more productive, and skyscrapers are getting taller. Still longevity is increasing so we still need to worry about it. And that is the whole point. We need something to worry about.

Now, it seems like we were worrying about nothing. Population growth is slowing, and it looks like we will go into an indefinite period of population decline. As we approach the end of the century the world population will peak at around 10-11 million people. It is then going into indefinite decline. Now people are worrying about population decline instead of population growth.

Population decline will lead to all kinds of problems. There won’t be enough young people to support old people and their entitlements. Historically, modern economies have grown due to population growth. What will happen when economies don’t grow any more. What will the political and social implications be as the population as a whole ages. Fewer young people with fresh ideas and more cranky old people who don’t like new ideas. It is much to worry about. And there we go. Something new to worry about. It looks like we dodged a bullet there.

I sometimes worry that someday we might not have anything to worry about. I wonder if there are people who worry about whether or not we have enough to worry about. Well, at least I have enough to worry about. So I am happy.

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