Magazine 杂志：Overpopulation
by John Kuti (written in 2003)
I come from the south of England, in the most densely-populated corner of a small island, which, you might think, is full of people. (The UK as a whole has 2.4 people per hectare.) I have never gone hungry. The only time when I wish there were less people is on rush-hour trains. However, one of the most interesting findings of the census of 2001 was that a million people were missing. Or at least there were a million people less than the authorities expected. Should we be happy that we have more space and less mouths to feed? I don’t know.
As I start writing this article the world population (according to the Office of Population Research at Princeton University) stands at 6,315,850,431.
Doom, version 1
In 1798 Robert Malthus wrote an essay which got economics the name of the dismal science. It was called “The Principle of Population”. He said that it was impossible for the number of people to increase, and even worse, it was impossible for the standard of living to rise. The argument went like this:
1. population naturally increases geometrically: 2, 4, 8, 16…
2. food production increases arithmetically 2, 4, 6, 8…
3. so, population will be controlled by lack of food, the same as it is for animals. Some people will always be starving.
A lot of people disliked Malthus’ point of view. Often, because it seemed to go against the idea of progress, which was so important for other social theories of the time. Anyway, the experience of the next two centuries shows that something must be wrong with the theory. In the 19th century world population rose from 1 to 1.7 billion. In the 20th, it increased to about 6 billion.
Doom, version 2
In 1961, J.G. Ballard wrote a story called Billenium. It’s about a world where the population has gone on increasing at 3% a year to reach a figure of at least 20 billion, although the true number is kept secret. To make space for growing food, everyone lives in giant cities where the buildings are divided into little cubicles. A single person can have 4 square metres and a married couple six. Everyone has enough to eat, but life is certainly very inconvenient. People spend most of the time waiting in queues for the bathroom or anywhere else they want to go.
Reality
The real situation is not as bad as these alarming predictions. A very surprising and dramatic change is happening in the world, but it is not what Malthus or Ballard predicted. To understand the statistics, we need first to think about the two ways the number of people can go up.
The Fertility Rate
The most obvious way to increase population is for more babies to be born. If the population is exactly constant, the average woman has 2.1 children. This number is called the "replacement rate". These rates are going down very fast. The peak was in the period 1965-75 at 4.9, now the rate for the world as a whole is 2.8. However, there is still a big difference between the developed countries, where the rate is 1.6 and poor countries where it is 3. To quote some extreme examples, in Italy the figure is 1.2 and in Zambia 5.6.
Life expectancy
The other reason why there are more people now is that we live longer. This figure also shows a dramatic change. The people born in 1950 could expect, on average, to live 45 years. Now the world life expectancy at birth is 65, and the United Nations predicts this will increase to 76 in the next 50 years.
Predictions of doom
Malthus and Ballard were still right about some things. The dismal picture painted by Malthus is still true in poor countries where 18 million people starve every year, and more than a billion people don't have a supply of clean drinking water. Ballard is right about the trend towards city life. By the year 2006, the United Nations predicts that more than 50% of people will live in cities.
City life in the developed world
At least in the rich countries, the move into cities seems to be connected with falling fertility rates. It is more expensive to have a child in the city, and children are less useful as workers. Women receive a better education and are able to work – so they have more to lose by becoming mothers. City life seems to encourage individualism – people become more interested in getting an education and a career. They marry later in life, and divorce more often, so producing smaller families.
At the moment, it seems quite possible that the same pattern will be repeated everywhere. One UN forecast now foresees a world population of about 5 billion in 2100. But, the more time you spend looking at predictions the more you realise that the human race is a surprising phenomenon. It looks like we will have a clearer idea of what will happen in ten or twenty years time when the present generation of parents moves beyond child-bearing age.
Now there are 6,318,042,422 people.
Glossary
average (n.): the figure you get if you add together a set of numbers and divide that total out equally.
census (n.): the official procedure for counting all the people in a country.
constant (adj.): staying the same, not changing.
cubicle (n.): a very small closed off space, e.g. a shower cubicle.
densely-populated (adj.): with a lot of people living close together.
dismal (adj.): dark, sad and depressing.
encourage (v.): to make something happen or increase.
figure (n.): number.
foresee (v.): to predict, to see something that might happen in the future.
go on –ing (v.): continue.
hectare (n.): the size of a square 100 metres by 100 metres.
lack (v.): not having something.
peak (n.): the highest point.
predictions (n.): things people say about what they think will happen in the future.
starving (adj.): dying from lack of food.
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