POPULATION GROWTH AND CHANGE

• Key Terms:• Population growth• Basic Demographic Equation• Rate of Natural Increase• Doubling time• Carrying Capacity• Population Projection• Mathematical methods• Component methods• Baby boom

A.D.2000

A.D.1000

A.D.1

1000B.C.

2000B.C.

3000B.C.

4000B.C.

5000B.C.

6000B.C.

7000B.C.

1+ million years

8

7

6

5

2

1

4

3

OldStoneAge New Stone Age

BronzeAge

IronAge

MiddleAges

ModernAge

Black Death — The Plague

9

10

11

12

A.D.3000

A.D.4000

A.D.5000

18001900

1950

1975

2000

2100

Future

Billions

Source: Population Reference Bureau; and United Nations, World Population Projections to 2100 (1998).

World Population Growth Through History

Millions

Annual Increase in World Population

0

10

20

30

40

50

60

70

80

90

100

1951 1956 1961 1966 1971 1976 1981 1986 1991 1996 2001 2005

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

Billions

0

1

2

3

4

5

6

7

8

9

10

1950 1970 1990 2010 2030 2050

Less Developed Regions

More Developed Regions

Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

Growth in More, Less Developed Countries

Trends in Population Growth Worldwide

Population Increase and Growth Rate, Five-Year Periods

80

8783

7976 76 75

72

0

10

20

30

40

50

60

70

80

90

1980-1985

1985-1990

1990-1995

1995-2000

2000-2005

2005-2010

2010-2015

2015-2020

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Net population added per year Annual population growth rate

Mill

ions

Perc

ent i

ncre

ase

per y

ear

Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

Notes on Trends in Population Growth Worldwide

• This figure illustrates the lag between changes in the rate of growth and the net increase in population per year.• Over the period 1985-1995, the population growth rate declined (a reflection of declining fertility), yet millions of people were added to the world’s population (which peaked around 1985, when 87 million people were added each year). • From 2000 on, the growth rate will continue to decline. Between 2015 and 2020, we will still be adding 72 million people each year. Why? Because the generation of women now having their children is very large as the result of high fertility in their mothers’ and grandmothers’ generations.

World Population Clock

Natural Increase per World

More Developed Countries

Less Developed Countries

Less Developed Countries (less China)

Year 80,794,218 1,234,907 79,559,311 71,906,587

Day 221,354 3,383 217,971 197,004

Minute 154 2 151 137

2005

Source: Population Reference Bureau, 2005 World Population Data Sheet.

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

© 2006 Population Reference Bureau

• Birth rates and death rates are declining around the world. Overall economic development, public health programs, and improvements in food production and distribution, water, and sanitation have led to dramatic declines in death rates. And women now have fewer children than they did in the 1950s. • Nevertheless, if death rates are lower than birth rates, populations will still grow. • Also, it is possible for absolute numbers of births to increase even when birth rates decline.

Notes on Birth and Death Rates, Worldwide