Population explosion and declining population

Population explosion is a very rapid and large increase of human population in a short time, when the birth rate stays high but the death rate falls sharply. World population was about 1 billion in 1800, 2.5 billion in 1950 and passed 8 billion in November 2022; most of this growth happened after 1950, mainly in developing countries.

Reasons for population explosion

1. Fall in death rate – better medicine, vaccines, antibiotics and control of epidemics (smallpox, cholera, plague).
2. Better food supply – Green Revolution, high-yield seeds, fertilisers and irrigation reduced famine.
3. Improved sanitation and safe water – lower infant and child mortality.
4. Increased life expectancy – more people live to old age.
5. High birth rate – early marriage, low use of contraception, desire for sons, children seen as labour and old-age security.
6. Illiteracy and poverty – especially low education of women.
7. Religious and cultural beliefs against family planning.

This is explained by the demographic transition model: stage 1 high birth and death rates; stage 2 death rate falls but birth rate stays high (explosion); stage 3 birth rate falls; stage 4 both low.

View on the current trend of decreasing population in developed countries

Many developed countries such as Japan, South Korea, Italy, Germany and East European countries have a total fertility rate below the replacement level of about 2.1, and their populations are shrinking or ageing. My view:

• Causes: high cost of living and child-rearing, women's education and careers, late marriage, easy contraception, urban lifestyle and individualism.
• Positive side: less pressure on resources and environment, more investment per child, higher living standard.
• Negative side:
  • Ageing population – fewer workers support more retired people; pension and health costs rise.
  • Labour shortage – slower economic growth and less innovation.
  • Empty villages and schools, smaller consumer market.
• Responses: incentives for child birth, child care and parental leave, higher retirement age, automation and robotics, and immigration of workers (which also affects countries like Nepal through foreign employment).

So the trend is a natural result of development (stage 4 of demographic transition). It is not harmful by itself, but it must be managed with balanced policies; meanwhile the global challenge remains high growth in poorer countries.