Population Geography: Distribution and Density

Population Geography

• Looks at spatial aspects of population like distribution, reasons for living in certain areas, and relationship between population and environment

Tools for Studying Population

• Maps, graphs, and population pyramids are used to study population patterns and trends
• Demography is closely related to population geography
• Demography is the statistical study of human populations

Statistics

• Information in number form
• Demographers collect statistics to forecast future populations

Population Density

• This is the average number of people living in an area
• It is expressed as persons per square mile or square kilometer
• Calculated by dividing total population by land area
• Population densities vary greatly around the world
• Canada has just 8 persons per square mile
• The Gaza Strip has over 5,700 people per square mile
• Population density reflects the size of a country, the size of its population, and environmental conditions
• Most of Canada's 31.6 million people live along the country's southern border, making it densely populated

Population Distribution

• People are spread unevenly across Earth
• About 90% of the world's population lives in the Northern Hemisphere
• People live in lowland areas, especially along fertile river valleys
• Four major population clusters are East Asia, South Asia, Europe, and Eastern North America
• Smaller clusters include the Nile Valley in Egypt and the island of Java in Indonesia
• Population distribution is influenced by favorable settlement conditions
• Areas with mild climates, fertile soils, and fresh water tend to be more populated
• Polar regions, deserts, and rugged mountains tend to be less populated

Population Change

• Geographers use statistics to study population changes
• Three major factors influence the number of people in a place: birthrate, death rate, and migration

Birthrate

• Number of births each year for every 1,000 people

Deathrate

• Total number of deaths each year for every 1,000 people

Migration

• Moving from one place to live in another
• Emigrants leave a country to live elsewhere
• Immigrants come to a new country to live

Migration Factors

• Push factors cause people to leave a location, e.g., lost job, lack of opportunity, environmental hazards
• Pull factors attract people to a new location, e.g., better job or higher pay
• Most people migrate for economic reasons

Refugees

• People forced to leave their homes and cannot return
• They often leave due to safety concerns or discrimination

Natural Increase

• This rate is based on births and deaths only, not migration
• Calculated by subtracting death rate from birthrate, expressed as a percentage
• The rate in the US is about 0.6% each year

Natural Increase Rates

• Vary greatly in countries around the world
• The highest rates are in Africa and Southwest Asia, sometimes 3% or higher
• Moderate rates are in Central and South America and Southeast Asia, between 1 and 3%
• The lowest rates are found in most European and North American countries, Australia, and New Zealand, less than 1%
• Some countries, like Italy, Russia, and Japan, have negative growth rates

World Population Growth

• Reasons for these increases include
• Medical advances
• Agricultural advances
• Sanitation advances

World Population Trends

• In A.D. 1, the world's population was about 300 million
• By 1600, it doubled to 600 million
• Farm technology and public sanitation improved which allowed modern medicine to arise and cities expanded
• The world population passed 2 billion before 1930
• The world population doubled again to 4 billion by 1975
• In 2000, there were more than 6 billion people
• Earth now has more than 8 billion people, increasing by nearly 80 million each year
• The world's population has increased rapidly in the last 200 years
• Overpopulation is a concern, referring to a situation where the number of people is too large for available resources

Demographic Transition Model (DTM)

• Shows how birth and death rates dropped as Western countries developed
• Most technologically advanced countries have transitioned from high to low birth/death rates
• Many poorer countries are experiencing similar population changes

First Stage of DTM

• Birth and death rates are high
• Parents have many children, with many not surviving to adulthood
• The infant mortality rate is high
• Population remains relatively stable
• This is common in agricultural countries

Second Stage of DTM

• Death rate begins to fall due to improvements in medicine and healthcare for children
• Infant mortality rate drops significantly
• Birthrate remains high, leading to population growth
• Economic improvements and advanced farming cause rural to urban migration
• Birthrate begins to fall near the end of this stage as modern urban society expands

Third Stage of DTM

• Birth and death rates are low
• Total population growth is low
• All economically advanced countries have reached this final stage, including the United States, Canada, Japan, Singapore, Australia, New Zealand, and nearly all European countries
• These countries have experienced a transition from high birth/death rates in an agricultural society to low rates in an urban/industrial society

Future Populations

• Demographic information can be used to make population projections
• Population projections estimate future population size, age, and growth rate
• Forecasting population growth is tied to future birthrates, which are unknown
• Multiple projections are often made, and the less reliable they are, the farther into the future they are projected