Population geography refers to the number of inhabitants of a territory during a specific period of time. This change may be positive as well as negative. It can be expressed either in terms of absolute numbers or in terms of percentage.
Growth of Population: Change of population in a particular area between two points of time is known as growth of population. For example, if we deduct the population of India 1991 (84.63 crore) from population of 2001 (102.70 crore) then we shall get the growth of population (18.07 crores) in actual numbers.
Growth Rate of Population: This is the change of population expressed in percentage.
Natural Growth of Population: This is the population increased by difference between births and deaths in a particular region between two points of time.
Natural Growth = Births – Deaths
Actual Growth of Population: Births – Deaths + In Migration – Out Migration
Positive Growth of Population: This happens when the birth rate is more than the death rate between two points of time or when people from other countries migrate permanently to a region.
Negative Growth of Population: If the population decreases between two points of time it is known as negative growth of population. It occurs when the birth rate falls below the death rate or people migrate to other countries.