Population Growth

Worldwide Population

• Year 2000– 6.1 billion inhabitants

• Year 2030– 8 billion inhabitants

• Year 2050– 9 billion inhabitants

200,000 people a day are being added!

• Beginning of human existence– Growth rate was about 0– Hunting and gathering kept numbers small

• Modern era of population growth– Late 1700’s– Accelerated in late 1800’s– After WWII, population increased dramatically

in less developed countries

Mortality Revolution

• Population growth due to falling death rates– Not because of increased birth rates

– Improved food supply– Improved sanitation– Increased living standards

Rate of Natural Increase

• Birthrate

• Death rate (mortality rate)

Subtract the death rate from the birthrate.

Convert to a percentage by adding a decimal point between tens and ones place

The world’s growth rate was 1.4% in 2000

Doubling Time

• Approximate number of years it will take for a population to double in size

• Calculated by dividing 69 (mathematical constant used for compounding percentages) by the rate of natural increase

Example: For US 69/.8 = 86 years

Analyzing Population Pyramids

• Shows sex and age distribution• Can examine how events affect the

population– Wars– Famines– Epidemics

• Determines population growth of specific age groups

• Can be used in determining public policy

Migration

• Push Factors– Those that cause

people to leave a location

• Pull Factors– Those that attract

people to a new location

Demographic Transition Model

• Model that shows how birthrates and death rates dropped as Western countries developed modern economies and industries

• Stage One– Birthrates and death rate both high– Lots of children, but poor health conditions

mean many do not live– Population does not grow much (stable)

• Stage Two– Death rates fall due to improvements in health

care– Move from rural to urban areas (improved

agriculture)– End-birthrates begin to fall per urban

populations

• Stage Three– Birthrates and death rates are low– Total population growth is low– Stage of economically advanced countries– Transition from agricultural society to urban

industrial society

• No countries in stage 1

Future Trends

• Most countries seeing falling birthrates

• Future growth based on “momentum”

Practice

• United States– Birthrate 15– Death rate 7

• Rate of Natural Increase

• Algeria– Birthrate 23– Death rate 5

• Rate of Natural Increase

Practice

• Africa– Birthrate 42– Death rate 13

• Latin America– Birthrate 27– Death rate 7

• North America– Birthrate16– Death rate 9

• Asia– Birthrate 25– Death rate 8

• Europe– Birthrate 12– Death rate 11

• Oceania– Birthrate 20– Death rate 8