How has global population changed?
Population numbers change over time, influenced by births, deaths and migration into or out of the area. Global population levels, having grown slowly for most of human history, are now rising.
The five stages of the demographic transition mode
- Total population is low but it is balanced due to high birth rates and high death rates.
- Total population rises as death rates fall due to improvements in health care and sanitation. Birth rates remain high.
- Total population is still rising rapidly. The gap between birth and death rates narrows due to the availability of contraception and fewer children being needed to work - due to the mechanisation of farming. The natural increaseis high.
- Total population is high, but it is balanced by a low birth rate and a low death rate. Birth control is widely available and there is a desire for smaller families.
- Total population is high but going into decline due to an ageing population. There is a continued desire for smaller families, with people opting to have children later in life.
The Demographic Transition model
The demographic transition model shows population change over time. It studies how birth rate and death rate affect the total population of a country.
How the demo transition model works
As a country passes through the demographic transition model, the total population rises. Most LEDCs are at stage 2 or 3 (with a growing population and a high natural increase). Most MEDCs are now at stage 4 of the model and some such as Germany have entered stage 5.
Population structure and population pyramids