Population Clock

http://www.worldometers.info/world-population/

Chapter 19: Population Ecology

Human Numbers Through Time: A.D. 0

Taken from Nova online

300 million

A.D. 1000

310 million

1800

1 billion65% Asia, 21% Europe, 1% North America

1927

2 billion

1960

3 billion

1974

4 billion

1987

5 billion

1999

6 billion62% Asia, 12 % Europe, 12% Africa, 9% Latin America, 5% N. America

2050

Population will more than likely will reach 9 billion peopleNearly all growth will take place in developing countries

PGR: increase in a country’s population during a period of time (1 year).

PGR = birth rate – death rate

Rapid PGR: Africa and Middle EastSlowest PGR: Europe and North America

Average Annual Population Growth Rate, 1980-98

1980: 4.4 Billion2000: 6 Billion

Population (shown in millions)

In the past few decades…

• Death rates have declined – Living longer in both industrial and developing countries

immunization, health care, technology– Avg life expectancy: 78

• Birth rates have declined– Parents are choosing to have less children– Access to family planning– More women starting families later in life

* PGR remain high though because birth rates have not fallen as much as death rates

• PGR have started to decline• But will continue to increase because the population base has

become larger. • Growth rates tend to be higher in low and middle-income

Population Growth Rate

Population momentum• Phenomenon that occurs when a large proportion of a country’s population

is of childbearing age. • Occurs in low-income countries• More than a third of the population is under the age of 15

Why so many children?

• Fear their babies may die• Need laborers to work• Ensure that they themselves will

be cared for in their old age• Lack access to education and to

family planning

To reduce fertility rates

1. Greater access to primary health care and family planning services

2. Receive a basic education (esp. girls and women)

3. Have government serviced that help protect them when sick, old, unemployed

Are we going to reach a carrying capacity?

• Carrying capacity: number of individuals the environment can support over a long period of time

• Some say we have already exceeded the carrying capacity

• Others say billions more can be sustained on earth

• Consensus– World population will continue to grow until after

the middle of this century– Peak of some 9 billion– Perhaps declining in the latter years

What controls population size?

• Density-Independent Factors– Weather, floods, fire– Reduce population by the same proportion

regardless of size

• Density-Dependent Factors– Shortages of food, shelter– Triggered by increasing population density

In groups of 2 or 3, answer the following (in complete sentences)

1. What do you think daily life might be in your town in 2050 when there are 9.2 billion people on this planet?

2. What types of technological changes will be needed to accommodate the world’s growth?

3. What do you think will be the greatest environmental concerns at that time?

4. Do you see population growth becoming a major political issue by 2050? Why or why not? What types of population issues might people be talking about at that time?