ECO Note Home Page

Human Population

I.  Population Growth Predictions

Doubling Time

  The time it takes a population growing at a given rate to double in size

world population growth


II. Consequences of exploding population

bulletresource depletion
bulletloss of ag land
bulletloss of biodiversity
bulletincrease in disease
bulletpopulation  migration
bulletloss of wetlands
bulletincrease in waste production
consequences of overpopulation

III.  Opposing arguments that predict the future of the human population

Malthusian overpopulation

People use resources and produce pollution. 

Eventually, resources will become scarce and pollution will become debilitating. 

The population will then decline as a result of resource scarcity and pollution.

Cornucopian  view 

People are creative. 

Any problems that develop, as the population increases will spark creative inventions that enable further population growth. 

There will be no population decline.

IV.  Reasons for human population explosion

Causes of disease recognized
Improvements in nutrition
Discovery of antibiotics
Improvements in medicine
Increase in number of women who actually reach child-bearing age
Short doubling times in some countries

IV. Stats

World population is 6.7 billion +


By 2025 it will be 7.8 billion

Between 1963 & 2004 the world’s population grew from 3.2 billion to 6.7 billion people


The growth rate dropped from 2.2% to 1.33% which still adds 77-80 million people a year

93% of the world’s population live in areas with fertility reduction programs.


Most governments spend only 1% of their national budget on fertility programs

(Since being elected President Bush has cut funding to international programs that control fertility)


There are 6.7 billion people on Earth

If each one stood up, pronounced their name, and sat down

It would take 600 years to complete roll call

By 2025 it will take 1,000 years to complete this exercise


U.S. population has grown from


90 million in 1900


273 million in 1999


300 million 6:47am on Tues Oct 18, 2006


301,139,947 now


394 million in 2050?

bullet60% of the population in the U.S. is because births outnumber deaths by 1.64 million/year

(40% of the growth is from immigration 1.1million/year)

V.  Developed vs Developing Nations


Developed Nations


Moderately Developed Nations


Developing Nations

82% of the world’s population lives in developing countries

98% of the world’s population growth; 75 million people a year occurs in developing countries

VI.  Population Change =

Births + Immigration) - (Deaths + Emigration)

zero population occurs when:

(Births + Immigration) = (Deaths + Emigration)

VII. Population Decline

bullet88 countries representing only 13% of the world’s populations have stable or declining populations.
bulletJapan has a low birthrate and almost 0 immigration. The population is expected to decline from 127 million in 2000 to 67 million in 2100.

What special problems can arise?

1.Labor shortages

2. Severe medical and social problems because there are not enough people to take care of the older generation

3.  Fewer people have to pay more to keep social security type programs solvent.


VIII. Factors that Influence Population Growth

A). Biological Factors

1). Fertility

How many women are having children and the number of children each woman will have.

Total Fertility Rate

Average number of babies a woman will have.

Crude Birth Rate 

Number of births per 1000 individuals per year

2.1 children/woman is the replacement rate


The average number of children a woman will have has dropped from 5 in 1950 to 2.53 in 2005


1.5 in developed countries


3.5 in developing countries


5.2 in Africa


Lowest is Hong Kong at .91 and the highest is Somalia at 6.84


U.S.  = 2.08 children/woman

2). Crude Death Rate

number of deaths per 1000 individuals

High death rates usually indicate infant/children mortality.

If the death rate falls—people live longer & the population will increase even if the birth rate falls

But eventually the population decreases because people that live longer have fewer children

 life expectancy (how long an infant is expected to live)

bullet75 years in developed countries
bullet66 years in developing countries
bullet39 years in Botswana

Infant mortality: how many babies out of 1000 die before their first birthday

bullet6.5 in the U.S.
bullet8 in all developed countries
bullet62 in developing countries

What factors affect the death rate?


food supplies




public health systems




water supplies

3) Age Distribution

Age structure or population profile is the number of people of each age group (a group is 5 years) divided by sex (males on the right and females on the left)

Tracking the Baby Boomers

In 2000 baby boomers made up 50% of all adults

By 2030 2-% of the U.S. population will be over 65 years old

Profiles help to determine how many individuals are capable of giving birth

Used for economic and political decisions:

Pension and Medicare programs

Who to market to

Predict labor shortages

Need for schools

Population Profile

Developed Nations Developing Nations

Population Momentum

The effect of the current age structure of future population growth.

Young populations will continue growing due to reproduction of already existing age groups


B). Social Factors That Influence Birth Rate

1). Cultural and religious practices

2). Status and desires of women in the culture

bulletequal rights
bulletopportunities for women particularly education.
bulletage of marriage and first child


Women work 2/3 of all work hours for only 1/10 of the world’s income and .01% of the property.

3) Availability of birth control and legal abortion

bulletcontraception use is only 26% in Africa
bulletBirth control for married women has gone from 10% in 1960 to 49% in 1999 (world wide) and 59% in developed countries.
bulletExpanding family planning world wide would cost $17 billion a year and would result in a decrease:
bulletof 5.8 million births &
bullet5 million abortions per year

4). Infant mortality

5). Children in the labor force

6). Cost of raising children

7). Availability of pension systems

8). Availability of health care

9). Overall death rate


C). Political Factors

Government policies on population growth and immigration.

This may include tax breaks and services for children.

Limits on the number of children a couple can have.

(voluntary or mandatory)

Does the government have any right to interfere with the birth rate?

How much affect can the government have?


The fertility rate in China is 1.8 children/woman


The fertility rate in India is 3.2 children/woman


1.Increase family planning

2.  Concentrate on development & economics



IX). Population Growth and Standard of Living

Standard of living refers to the quality of life

                    As  the birthrate increases Ý

                    The standard of living decreases ß

Which comes first?

Does a high birth rate decrease the standard of living  or does a low standard of living increase the birth rate