Overpopulation, underpopulation and optimum population

Overview

What each of the three terms means, why the optimum can never be fixed as a number, and why a densely populated country is not automatically overpopulated.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What is overpopulation?

   Model answer

   Overpopulation exists where there are too many people for the resources and the level of technology available, so that the standard of living falls. The symptoms are unemployment and underemployment, food shortage and malnutrition, pressure on water, fuelwood and farmland, overcrowded and inadequate housing, falling farm sizes, soil erosion and deforestation, out-migration, and in extreme cases famine. It is a relationship between people and resources, not a particular number of people.

2. 2

   What is underpopulation?

   Model answer

   Underpopulation exists where there are too few people to use the resources of an area fully and efficiently — its farmland, minerals, energy, forests and industrial capacity — so that total output and income per head are lower than they could be. More people, or more capital and technology to work alongside the existing people, would raise the standard of living for everyone. The symptoms are labour shortages, resources left unexploited, services that are expensive to provide across a scattered population, and government efforts to attract immigrants.

3. 3

   What is optimum population?

   Model answer

   Optimum population is the population size which, with the resources, technology and capital available at the time, produces the highest output and the highest standard of living per head. Above that size the country is overpopulated, below it the country is underpopulated. It is a theoretical ideal used for reasoning about the balance between people and resources, and no country has ever been able to state its own optimum as a figure.

4. 4

   Why can the optimum population never be pinned down to a number?

   Model answer

   Because it moves. Every new resource discovered, every improvement in technology, every change in trading relationships and every change in what a society regards as an acceptable standard of living shifts it. Standard of living is not a single measurable quantity either, so even the thing being maximised is contested. The optimum is therefore a concept to think with, not a target a government could aim at, and any statement that a country has too many or too few people is a judgement about the present combination of people, resources and technology rather than a permanent fact.

5. 5

   What would the standard graph of these three concepts look like?

   Model answer

   Standard of living, or output, per head goes up the vertical axis and total population size along the horizontal axis. The curve rises from the left as a growing population allows more of the resource base to be worked and lets specialisation and economies of scale develop, reaches a peak, then falls away as each additional person adds less to output than they consume. The peak is the optimum population. Everything to the left of it is underpopulation and everything to the right is overpopulation, and the curve as a whole shifts upwards and to the right whenever technology improves or new resources are found.

6. 6

   What single relationship do all three terms describe, and why does that make them slippery?

   Model answer

   All three describe the balance between the number of people and the resources, technology and capital available to them, judged by the standard of living that results. That is what makes them slippery: because the resource and technology side can change while the population stays the same, one unchanged population can be overpopulated in one decade, at its optimum in the next and underpopulated later. The same population size also means completely different things in two different countries. None of the three terms describes a quantity of people; each describes a ratio.

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.