Malthus and Boserup, and how they hold up

Overview

What Malthus argued about population and food supply, malthus's positive checks and his preventive checks and carrying capacity.

What you need to know

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Questions from this subtopic

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1. 1

   Explain what Malthus argued about population and food supply.

   Model answer

   Writing in 1798, Malthus argued that population, if left unchecked, grows geometrically — doubling, so 1, 2, 4, 8, 16 — while food supply can at best be increased arithmetically, so 1, 2, 3, 4, 5, because land is finite and each extra unit of output is harder to win than the last. Two such lines must eventually cross. Population will therefore outrun the food supply and reach a ceiling set by that supply, and once it reaches the ceiling it cannot grow further. In his scheme the food supply is the limit and population is the variable that runs into it.

2. 2

   Distinguish between Malthus's positive checks and his preventive checks.

   Model answer

   Positive checks operate after the ceiling has been reached and work by raising the death rate: famine, the malnutrition and disease that follow it, epidemics, and war fought over scarce land and food. He called them positive because they act, not because they are desirable. Preventive checks, also called negative checks, operate before the ceiling is reached and work by lowering the birth rate: delaying marriage, moral restraint, celibacy and abstinence, and simply not having children one cannot feed. As a clergyman he much preferred the preventive checks and regarded them as the only humane escape, and he did not advocate contraception.

3. 3

   What would Malthus's graph look like?

   Model answer

   Two lines plotted against time. Food supply rises as a straight line with a gentle constant slope, representing arithmetic growth. Population starts below it and rises as a curve that gets steeper and steeper, representing geometric growth. The point where the population curve crosses the food supply line is the crisis point, sometimes called the ceiling. Beyond it the population line cannot continue upwards: the checks operate, so it flattens off or falls back towards the food line, and the whole cycle can then repeat at a higher level.

4. 4

   Is Malthus optimistic or pessimistic, and why does the direction matter?

   Model answer

   Pessimistic. In his account population is the problem and the resource base is essentially fixed, so growth ends in misery unless people restrain themselves in advance. That is the exact reverse of Boserup's position, in which pressure from a growing population is the thing that triggers the resource base being expanded. Getting the direction the wrong way round — saying that Malthus thought pressure would produce innovation, or that Boserup thought population would be checked by food supply — is the commonest single error in questions on the two, and it usually shows up as an answer that contradicts itself later on.

5. 5

   What is meant by carrying capacity?

   Model answer

   Carrying capacity is the maximum population that a given environment can support indefinitely with the resources available, without the resource base being degraded. In Malthus's framework it is a fixed ceiling set by the food supply. In Boserup's it is not fixed at all, because innovation can raise it. Ecologists use the same idea for a species in a habitat, and modern neo-Malthusian writers apply it to the whole planet, setting the resources humanity consumes each year against what the Earth can renew in that time — the idea behind the ecological footprint.

6. 6

   Who are the neo-Malthusians and how did they widen the argument?

   Model answer

   They are twentieth and twenty-first-century writers who revived Malthus's reasoning in a broader form. Instead of food alone, they set population against water, energy, minerals, soil and the capacity of the atmosphere and oceans to absorb waste. The Limits to Growth, published in 1972, modelled resource depletion and pollution and projected collapse within a century on then-current trends; Ehrlich's The Population Bomb of 1968 predicted mass famine within decades. Their contribution is to add environmental limits and pollution sinks to Malthus's food limit, and to express the argument through carrying capacity and the ecological footprint rather than through arithmetic and geometric series.

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