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