Population growth & the Demographic Transition Model
For almost all of human history there were very few people on Earth — then, in just two hundred years, the number rocketed from one billion to eight billion. In this lesson we uncover why the world's population exploded, and we meet the three things that change any population: the birth rate, the death rate and migration. We ask what happens when there are too many, or too few, people for a country's resources, why some countries grow fast while others barely grow at all, and how consequences like the dependency ratio, standard of living and life expectancy follow. Finally we draw the Demographic Transition Model — the four-stage graph every country moves through as it develops — using Namibia and other examples along the way.
By the end you should be able to (NSSCO Geography 3.1a):
- Describe the reasons for the rapid increase in the world's population in recent times (the population explosion)
- Define the main components influencing population growth: birth rate, death rate and migration
- Describe the relationship between population growth and resources, and explain why over-population and under-population problems may result
- Identify and discuss the reasons for contrasting patterns of population growth in different world areas, influenced by differences in birth rate, death rate and migration
- Describe the consequences (benefits and problems) of different patterns of population growth, including the dependent population, dependency ratio, standard of living, life expectancy and infant mortality
- Describe and explain the different stages of the Demographic Transition Model