AP Human Geography Mrs. Bellisari

Chapter 2 - Key Issue #2- Why is Global Population Increasing?

What does this graphic tell us about world population growth between 1950-2012?

3 Measures of Population Change

• CBR - Crude Birth Rate–

• CDR - Crude Death Rate–

• NIR - Natural Increase Rate–

- To calculate natural increase in a country’s population, subtract CDR from CBR, after converting both numbers to percentages

What implications does the information in this map have?

What implications does the information in this map have?

Doubling Time•

• 2000 years ago – world population estimated at 250 million• Took 16 centuries to double to 500 million (1650)• 1820 (170 years later) – population doubled to 1 billion• 1930 – 2 billion

• POPULATION EXPLOSION! Why?

• 1975 – 4 billion• Today world population is doubling in 54 years• About 82 million people annually – still significant

J-Curve and S-Curve• J-curve – when the projection population shows

exponential growth. This is important because if the population grows exponential our resource use will go up exponential and so will our use as well as a greater demand for food and more.

• S-curve- traces the cyclical movement upwards and downwards in a graph.

• Carrying capacity- largest number of individuals of a population that a environment can support

Population GrowthThere are actually four elements that go into determining population growth

1. deaths2. births3. immigration4. emigration

TFR - Total Fertility Rate•

• Attempts to predict the future behavior of individual women in a world of rapid cultural change

• Population Reference Bureau estimates global population will reach 9.3 billion by 2050

• Rising TFRs in India, Indonesia, Bangladesh, Pakistan, Nigeria

• Countries and regions go through stages of expansion and decline at varying times

• Continuing high growth rates in Muslim countries of North Africa & SW Asia

• Saudi Arabia – one of highest growth rates in world

• Iran & Morocco – significant declines

• Demographers connect high growth rates with low standing of women

• Cultural traditions restrict educational and professional opportunities for women and men dominate per custom

Population Pyramids• Display percentages of each age group (5 year groups) by horizontal bar whose

length represents its share (males to left, females to right)• Population in a country is influenced by the demographic transition in 2 major

ways:– Percentage of population in each age group– Distribution of males and females

• Population composition = # of men and women & their ages (also includes marital status and education)

Age Distribution• Dependency ratio = number of people who are too young or too old to work,

compared to the number of people in their productive years• Divide population into 3 groups

– Age 0-14– Age 15-64– Age 65 and older

Japan’s Dependency Ratio

• Sex Ratio : Number of males per hundred females• In general, more males than females, but males have higher death rates• Europe & North America 95:100• Rest of world 102:100• USA males under age 15 105:100

– Women start outnumbering men at age 40– Women comprise 58% of pop over age 65