In: Chemistry
"Demographic Transition" is a model that describes population change over time. It refers to the transition from high birth and death rates, to lower birth and death rates as a country or state or region develops from a pre-industrial to an industrialized economic system.
The four stages to the demographic transition are as follows:
Stage 1: Pre-transition
Characterised by high birth rates, and high fluctuating death rates.
Population growth was kept low by Malthusian "preventative" (late age at marriage) and "positive" (famine, war) checks.
Stage 2: Early transition
During the early stages of the transition, the death rate starts to fall.
As birth rates remain high, the population grows rapidly.
Stage 3: Late transition
Birth rates start to decline and the rate of population growth decelerates.
Stage 4: Post-transition
Post-transitional societies are characterised by low birth and low death rates.