Population size impact and changes

Impact
Population size is not the only factor that determines our species impact on the environment.

• Resource use and pollution
• Amount of wealth
• Resource desire
• Resource need

Many environmental impact models are based on the assumption that all individuals in a population have the same resource use and waste profile and thus impact the environment equally.


Changes
4 main factors for population changes:

• Birth rate
• Death rate
• Inmigration
• Emigration

The measures of population change are:

• Crude birth rate or CBR = (Number of births)/(Total population) * 1000
• Crude death rate or CDR = (Number of births)/(Total population) * 1000
• Natural increase rate or NIR = (CBR-CDR)/10
• Doubling rate = 70/NIR
• Total fertility rate: The number of children every woman is having in a determined area. The total fertility rate in the world is 3, 1.7 in MEDCs and between 3 and 6 in LEDCs
• Also important to note: Population density = (Total population)/(Total area)