The World's Population

An Overview

Reading: Weeks, Chapter 2

Links Used for this Lecture

• Hooper Virtual Paleontological Museum
• World Trends in Population
• The Population Bomb Page (PBS)

Definitions

• The Population Growth Equation
• PG = B - D + NM
• PG = population growth
• B = births
• D = deaths
• NM = net migration
• immigrants (or "in-migrants") minus emigrants ("out-migrants")

More Definitions

• Population growth measures often stated as a rate
• Crude Birth Rate: births per 1000 people
• {(births in a year)/(midyear population)}*1000
• What is crude about it?
• Crude Death Rate: deaths per 1000 people
• {(deaths in a year)/(midyear popualtion)}*1000
• What is crude about it?
• Net Migration Rate: net in migration per 1000 people
• {(IN - OUT)/(midyear population)}*1000

World Population History

• Need only to consider births and deaths
• unless you believe in aliens
• NRI (natural rate of increase) = CBR-CDR
• Reasonable data exist only for last several hundred years
• Counting early populations is at best an educated guess
• While we may be wrong in estimating a given year's population, we know that we are on average about right . . .

Early Populations

• Measuring early population size
• Archaelogical method
• Identify activities from archaelogical evidence
• Infer how many people could be sustained by the environment if they were involved in those activities
• Backward projection method
• Look at how many people existed around the first time for which good records exist
• Deduce rate of growth that would produce this population, starting from when we think people began

Early Man

• Australopithecus
• 4-5 million years ago
• Primarily vegetarian forager
• Brain size 1/3 of today

Early Man, Continued

• Homo Habilis
• 1-2 million years ago
• hunter gatherers, tool makers
• larger brain than AP
• concentrated in Africa, Asia
• 3,000,000 - 10,000,000 people

Homo Sapiens

• 300,000 years ago:
• brain size similar to today's
• artwork and tools suggest increasing level of intelligence
• hunting, fishing, foraging still popular (humanness)
• Little population change

Cro-Magnons

• 35,000 years ago
• "Modern man"
• Hunting more prevalent
• Technological advances
• sophisticated paint formulas
• Probably little population change

Agricultural Revolution

• 10,000 years ago
• Reduction in nomadic activity, increased settling
• Domestication of plants and animals
• Population growth accelerated somewhat
• Birth rates probably rose
• Death rates may have risen, but more slowly

Acceleration of Technological Advances

• 5,000 years ago: Bronze Age; use of wagons and sailing vessels
• 4,000 years ago: Contraceptives in use in Egypt
• 3,500 years ago: Iron Age
• 3,100 years ago: Permanent roads in China
• 2,800 years ago: Anatomical models used in medical training in India
• AD 1: World Population 250-300 million

Entering Modern Era

• 700 Population explosion in China, first large urban developments
• 1230 Leprosy imported to Europe by Crusaders
• 1347-1351 Black Death/Plague; 75 million people die (earlier bout 542-597)
• 1492 Europeans discover the Americas
• 1495 Syphilis epidemic spreads through Europe
• 1500 World Population 450-500 million

The New World

• 1567 2 million South American Indians die of typhoid
• 1650 Extermination of American Indians begins, World Population 500,000,000
• 1750 Industrial Revolution begins in Europe
• 1790 First U.S. Census, U.S. population 3.9 million
• 1796 Smallpox vaccination introduced
• 1800 Beginning of Industrial Revolution in the U.S., World Population 1,000,000,000

Rapid Population Growth

• 1810 Food canning
• 1824 Sperm essential to fertilization proved
• 1853 Hypodermic syringe
• 1900 World Population 1,600,000,000
• 1927 Airplanes used to dust crops with insecticide, World Population 2,000,000,000 (doubled in 127 years)

Twentieth Century

• 1943 Penicillin used against infection
• 1945 Atomic bomb detonated
• 1952 Contraceptive pill produced
• 1954 Vaccine for polio
• 1957 Great famine in China; 20 million die
• 1960 World Population 3,000,000,000
• 1978 Test-tube baby born
• 1979 China implements government's one-child family program
• 1987 World population 5,000,000,000
• 1992 World Population 5,400,000,000

World Population

Growth Rate

Doubling Time

Suggested Readings

• Peters, Gary and Robert Larkin
• Population Geography, Dubuque, Iowa: Kendall/Hunt Publishing Company, 1989
• Menard, Scott "Regional Variations in Population Histories"
• Perspectives on Population, Menard and Moen, eds. New York: Oxford University Press, 1987