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Geography Chapter 6
Population Geography
- Total population of Earth is a balance between two forces: births and deaths.
- Current World and U.S. Population
- The world population reached 6 billion on May 26, 1999.
- Projections indicate 7 billion by February of 2012.
- Human Population Through Time
- Growth Rate
Thomas Robert Malthus was the first to point out that:
- Because of the natural human urge to reproduce, human population grows geometrically.
- exponential growth - 1, 2, 4, 16, 52, 64, 128, 256, etc.
- Food supply, at most, can only increase arithmetically.
- linear growth - 1, 2, 3, 4, 5, 6, 7, 8, etc.
- Since food is an essential component to human life, population growth in any area or on the planet, if unchecked, will lead to starvation.
- Preventative checks are those that lower the birth rate and include marrying at a later age and abstaining from procreation, birth control.
- Positive checks are those that increase the death rate. These include disease, war, disaster, and finally, when other checks don't reduce population, famine.
- Story: More Food for More People - But Not for All, and Not Forever
- World Population Distribution
- Unevenly distributed
- Approximately 75% of Earth's population occupies only about 5% of the land area, with the largest concentrations being in East and South Asia, Western Europe, and Northeastern North America.
- Habitable vs Uninhabitable
- Habitable land is suitable to live on.
- Of the earth's 57.5 million square miles of land, approximately 12 million square miles are habitable.
- Uninhabitable land is too hot or cold, too wet or dry, or too mountainous.
- Arable vs Non-arable
- Arable land can be used to grow crops.
- Of the earth's 57.5 million square miles of land, approximately 7.65 million square miles are arable.
- Non-arable land usually has at least one of the following deficiencies:
- no source of fresh water
- too rainy
- too hot (desert) or too cold (Arctic)
- too rocky or mountainous
- too salty or polluted
- too nutrient poor
- Arable land can be lost to droughts, erosion, improper farming practices, and urban sprawl.
- Non-arable land can be converted to arable land by irrigation, desalination, fertilizer, and PET film insulation.
- Most of these are very expensive.
- Exceptions - where people have developed an alternative way to make a living (for example: mining).
- Why do some areas have a very dense population?
- Human Migration and Cultural Interaction
- Immigrate or Emigrate?
 (immigrants, 4 min)
- Immigrate - to come into a country of which one is not a native for permanent residence.
(migrants, 3 min)
- Emigrate - to leave one's place of residence or country to live elsewhere.
- The Demographic Equation combines the effect of natural change in population and immigration:
Population (t + 1) = Population (t) + Natural increase (t) + Net migration (t)
- Natural increase from time t to t + 1:
Natural increase (t) = Births (t) − Deaths (t)
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Net migration from time t to t + 1:
Net migration (t) = Immigration (t) − Emigration (t)
- U.S. Migration
- Population Relocation - in the past, immigration was a population pressure release, providing new regions with in flux of needed population. Today, immigration is not large compared to local populations.
- Immigration Impacts - Unbalanced groups of cohorts represent immigration (usually young, single men.) Currently, woman are a growing component of immigration (going abroad to look for work to support families.)
- World Population Distribution
- Pattern of Unevenness:
- 1/2 of the world's population lives in cities.
- Europe and North America have approximately the same population.
- Europe has 70% less land than North America.
- 90% of world's population lives north of the equator.
- 1/2 of the world's population lives on 5% of land (90% live on 20% of land.) Most congregate in lowlands.
- Continental margins are favored - 2/3 of population live within 300 miles of the ocean.
- 35% to 49% of the Earth is uninhabitable.
- Population Density (relationship between people and the area they occupy).
- Arithmetic density - (crude density) number of people per unit area of land.
- North America - 32 people/sq mi
- South America - 73 people/sq mi
- Europe has - 134 people/sq mi
- Asia - 203 people per square mile
- Africa - 65 people/sq mi
- Australia - 6.4 people/sq mi
- Physiological density - population divided by arable land area.
- Agricultural density - rural population on arable land.
- Overpopulation - not a matter of density. It is a value judgment concerning numbers related to resources and environmental degradation.
- Carrying Capacity - population that an area can support (resources, energy, economic activity, etc).
- World capacity - 65 of the world's 190 countries are unable to feed their populations from within their own national boundaries.
Egypt imports 1/2 of its food - dependent upon international aid for food - receive 2nd largest amount of US aid. Isreal is the first.
30% of developing world population unable to feed its populations. China's (1.3 billion people) wheat harvest had been steadily declining due to water issues, while demand rises.
Japan - the world's biggest food importer - produces only 40% of its own food.
- Urbanization - transition from rural to urban population is rising dramatically.
- Over next 30 years almost all population increase will happen in urban areas.
- Urbanization often converts agricultural lands into cities.
- Millions of acres of productive Texas Blackland Prairie have been lost to urban sprawl within the Texas Triangle Megalopolis.
- Austin - Dallas/Ft. Worth - Houston/San Antonio
- Patterns of Urbanization
- Demographic Cycles - Industrialization and urbanization in the last 200 years have caused a transition in world population growth patterns
- Demographic Transition - sequence of changes over time in vital population growth rates.
- Stage 1 - High Stationary
- Preindustrial technology
- Longest stage - 98% of history
- High birth rate - needed for labor intensive economics
- High death rate - linked to high infant mortality
- Population is low but fluctuating
- Stage 2 - Early Expanding
- Early Industrial technology
- High birth rate and lower death rate due to medical technology and lower infant mortality.
- Population rapidly expands
- Stage 3 - Late Expanding
- Mature Industrial technology
- Death rate continues to decline at low pace
- Big drop in birth rate - linked to urban-industrial society
- Expansion of population slows
- Stage 4 - Low Stationary
- Highly urbanized with a shift to postindustrial technology
- Birth and death rates stable and low
- Population is stationary
- A Fifth Stage is beginning to emerge
- Death rates equal to or greater than birth rates = a decline in population
- Changes in economics and child mortality result in smaller families - woman entering the workforce change the family structure. The level of development in a country is no longer revealed by fertility rates.
- Rich, industrialized world - Japan and Europe
- The "S" Curve
- How does the world fit into this pattern today?
- No Stage 1 nations because of improved medical care, sanitation, and technology.
- Stage 2 describes all human groups in early history.
- Today's stage 2 countries are Third World countries with uncertain low levels of food production, subsistence economic systems. Increasing development and associated socio-economic changes are moving some of these countries into Stage 3.
- Mentifacts vs. artifacts = lag
- Stage 4 - US, Canada, Europe, Australia-NZ, Japan - the developed, industrialized nations.
- Rule of 70 is a useful rule of thumb that roughly explains the time periods involved in exponential growth at a constant rate.
- A 1% annual growth rate results in population doubling every 70 years.
- At 2% doubling occurs every 35 years.
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