Impacts of population growth

As noted in Study Session 1, an increase in the number of people on Earth will mean that the impacts of their activities will increase too. However, it is important to note that this is not a simple cause and effect relationship. High population growth may deplete resources and trigger social or economic problems, but these same problems may also contribute to the causes of high population growth.

The impacts of population numbers on water resources and sanitation are covered in other study sessions. In this section, we will look at the links between rapid population growth and problems with food, health and poverty.

Population growth and food security

As the population grows, the amount of food required to adequately feed people is increasing. Food security exists when all people at all times have physical and economic access to adequate, safe and nutritious food that meets their dietary needs for an active and healthy life (WHO, n.d.). In many developing countries, the numbers of hungry, malnourished people who don’t have food security are growing.

In Africa, agricultural production is increasing, but it is still lagging behind population growth. This means that even though the proportion of the population with inadequate food is decreasing, the total number of people is increasing. Graff and Bremner (2014) reported that between 1992 and 2010, the proportion of underweight children in sub-Saharan Africa decreased from 27% to 22% of all children, but the number increased from 24.8 million to 30.3 million.

One of the long-term consequences of malnutrition in children is stunting, which means children are not the height expected for their age. Stunting also affects child development and health, with the result that stunted children are less successful at school and are more vulnerable to anaemia, diarrhoea and some other diseases.

Food security can be improved by increasing the quantity and quality of food produced. This could be by bringing more land into cultivation or by improving crop yields by irrigation or the use of fertilisers. However, these ‘solutions’ to the problem will all have environmental impacts that need to be weighed up against the potential benefits.

Population growth and health

Population growth has a number of effects on health. Rapid population growth increases demand for health services, infrastructure, and financial resources. For a rapidly growing population, a shortage of health workers and resources causes difficulties in accessing health care services.

The number and spacing of children per family both have significant effects on health. Women who have many children are more likely to become ill than those with small families. Furthermore, the gap between children has a significant effect on the survival rate of the child. Figure 2.7 shows the difference in child survival for children born less than two years apart compared to a three-year interval.

Figure 2.7 Birth spacing. The time interval between births in a family has a very significant impact on the survival rate of the children. (Adapted from Graff and Bremner, 2014)

The health implications of population growth are closely linked to poverty, which is the subject of the next section.