ZIMSEC O Level Geography Notes: Population: Population growth

• is an increase in the number of people that reside in a country, state, county, or city
• There are several factors which affect the growth of a population
• A country’s population grows as a result of natural births taking place within the community/country/region
• Births increase the population
• It can also grow as a result of people migrating from other areas into the country or region
• This is known as immigration
• Emigration causes a population to grow
• The population growth is however affected by people who die in the community
• Deaths decrease the population
• The population is also affected by those who migrate to other areas
• Emigration results in a decrease in the population
• Population growth can therefore be regarded as a system, consisting of inputs, processes and outputs

Births are positive inputs to population growth.

InputsProcessesOutputs
BirthsNatural ChangeDeaths
ImmigrantsTotal PopulationEmmigrants
Migrants
• The population growth rate as a percentage can be obtained using the formula:
• $\text{Population Growth Rate} = \dfrac{ ( live\enspace births+immigrants ) \enspace - ( deaths+emigrants )}{Total\enspace Population} \text{x}\dfrac{100}{1}$
• Population in the world is currently (2017) growing at a rate of around 1.11% per year (down from 1.13% in 2016)
• In 1992 the world’s average growth rate was at 1.7%
• Zimbabwe’s growth rate in 2013 was 3.0%
• Thomas Robert Malthus, a population theorist noted a relationship between population growth and resources.
• He mentioned that unchecked population growth would outstrip food supply
• Population growth rates are higher in developing countries than in developed countries, adding more pressure on limited resources and thus increasing poverty