Population Increase. World Population Growth Natural Increase Fertility Mortality.

Population Increase

World Population Growth

Natural Increase Fertility Mortality

Crude Birth Rate (CBR) The number of live births per 1,000 population in a given year. Not to be confused with the growth rate.

Crude Birth Rates

Fig. 2-8: The crude birth rate (CBR) is the total number of births in a country per 1000 population per year. The lowest rates are in Europe, and the highest rates are in Africa and several Asian countries.

General Fertility Rate The number of live births per 1,000 women ages 15-44 or 15-49 years in a given year.

Total Fertility Rate (TFR) The average number of children that would be born alive to a woman (or group of women) during her lifetime if she were to pass through her childbearing years conforming to the age-specific fertility rates of a given year.

This rate is sometimes stated as the number of children women are having today.

Total Fertility Rates

Fig. 2-9: The Total fertility rate (TFR) is the number of children an average woman in a society will have through her childbearing years. The lowest rates are in Europe, and the highest are in Africa and parts of the Middle East.

Crude Death Rate (CDR) The number of deaths per 1,000 population in a given year.

Crude Death Rates

Fig. 2-12: The crude death rate (CDR) is the total number of deaths in a country per 1000 population per year. Because wealthy countries are in a late stage of the Demographic Transition, they often have a higher CDR than poorer countries.

Infant Mortality Rates

Fig. 2-10: The infant mortality rate is the number of infant deaths per 1000 live births per year. The highest infant mortality rates are found in some of the poorest countries of Africa and Asia.

Infant Mortality Rate The number of deaths of infants under age 1 per 1,000 live births in a given year.

Life Expectancy at birth

Fig. 2-11: Life expectancy at birth is the average number of years a newborn infant can expect to live. The highest life expectancies are generally in the wealthiest countries, and the lowest in the poorest countries.

Life Expectancy The average number of additional years a person could expect to live if current mortality trends were to continue for the rest of that person's life. Most commonly cited as life expectancy at birth.

Natural Increase Rates

Fig. 2-7: The natural increase rate (NIR) is the percentage growth or decline in the population of a country per year (not including net migration). Countries in Africa and Southwest Asia have the highest current rates, while Russia and some European countries have negative rates.

Rate of Natural Increase (NIR) The rate at which a population is increasing (or decreasing) in a given year due to a surplus (or deficit) of births over deaths, expressed as a percentage of the base population.

Rates of birth, death, and natural increase per 1,000 population

0

5

10

15

20

25

30

35

40

1950-1955

1955-1960

1960-1965

1965-1970

1970-1975

1975-1980

1980-1985

1985-1990

1990-1995

1995-2000

2000-2005

Birth rate Death rate

Natural Increase

Source: United Nations, World Population Prospects: The 2004 Revision, 2005.

Birth and Death Rates, Worldwide

Growth Rate The number of people added to (or subtracted from) a population in a year due to natural increase and net migration expressed as a percentage of the population at the beginning of the time period.

World Population Growth1950 - 2005

Fig. 2-6: Total world population increased from 2.5 to over 6 billion in slightly over 50 years. The natural increase rate peaked in the early 1960s and has declined since, but the number of people added each year did not peak until 1990.

The Lily Pond

Imagine having a pond with water lily pads floating on the surface.

The lily population doubles in size every day and if left unchecked will smother the pond in 30 days, killing all the other living things in the water.

Day after day the plant seems small and so you decide to leave it alone to grow until it half-covers the pond, before cutting it back.

On what day will the pond be half full? (From Meadows

et al. 1972)

THE 29th DAY!!!!THE 29th DAY!!!!