Population growth means the difference between the natural birth rate and death rate of an area/country When the birth rate is higher than the death rate it is called positive growth because the population increases, but when the birth rate is low’er than the death rate, then it is negative growth because ,the population decreases. But population growth rate is slightly different to the population growth, it is a change in the number of people living in a particular area between two given points of time. The net change between two points of time is expressed in percentage and is described as the growth rate of population.