4.2 - Population, resources and competing theories

Demand, supply and access

Resources are materials, energy and environmental services people can use to meet needs. Whether a population faces shortage depends on more than its size: consumption per person, technology, distribution, trade and environmental conditions also matter.

Suppose a region produces enough grain for 100 people but its population rises to 120 without an increase in production or imports. Grain available per person falls. However, even when total food is sufficient, some households can face hunger because they cannot afford it or conflict disrupts distribution. National availability and individual access are different questions.

Population can increase pressure on land and water, especially where supply is difficult to expand. Higher incomes can also increase demand through diets, appliances and travel. Conversely, reducing waste, changing consumption or improving efficiency can meet needs with fewer resources. A theory that focuses on population alone needs to be tested against these other processes.

Malthus and pressure on food supply

Thomas Malthus's 1798 argument emphasised the possibility that population growth would outpace food production. The simplified model assumes population can grow geometrically, multiplying over equal time intervals, while food supply grows arithmetically, by equal additions.

For example, population demand might follow 10, 20, 40, 80 units while food supply follows 20, 30, 40, 50. At first there is a surplus, but compounding growth eventually overtakes fixed additions. The crossing represents a potential shortage under those assumptions, not a prediction that every country runs out of food in a particular year.

Malthus discussed checks that limit population. Preventive checks, such as delaying marriage, reduce births. Positive checks, such as famine and disease, increase deaths. Here “positive” means an effect on the death rate, not something desirable. Shortages can raise mortality and restrict growth, but people are not simply passive victims of a graph.

The argument draws attention to limits: land, water and soil cannot always support expansion indefinitely. Its simple growth assumptions, however, do not incorporate all later improvements in yields, trade, contraception, falling fertility or changing consumption. Hunger can also be caused by unequal access rather than total population exceeding total food.

Boserup and induced innovation

Ester Boserup's 1965 argument reverses part of the causal story: population pressure can encourage people to change farming methods and increase production. A shortage is an incentive for innovation and intensification, producing more from a given area through additional labour, inputs or technology.

A community may shorten fallow periods, improve irrigation, use higher-yielding crops or invest in fertiliser and machinery. If extra output exceeds the extra demand, food per person can recover. A graph may therefore show food supply rising in steps when new methods are adopted, rather than continuing along one fixed straight line.