Population

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Population

• Chapter 2

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Importance of Studying Population

• 6.75 billion people living on Earthmore than
  ever
• Population grew faster during second half of 20th
  century than ever before
• Almost all population growth is now happening in
  LDCs

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Demography

• Def.- the scientific study of population
  characteristics
• Demographers statistically study spatial
  distribution of people by age, gender,
  occupation, fertility, health, etc.

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Where is the Worlds Population Distributed?
Population cartogram- shows size of the country
relative to its population rather than land area
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Population Concentrations

• 2/3 of people living on Earth are clustered
  around 4 regions
• East Asia
• South Asia
• Southeast Asia
• Europe

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• Most of these people in these 4 regions live near
  an ocean or river with easy ocean access
• 2/3 of world live within 300 miles of an ocean
  4/5 within 500 miles
• 4 clusters are generally low in elevation, with
  fertile soils and a temperate climate
• Clusters located in N. hemisphere b/w 10 and 55
  degrees latitude except for part of Southeast Asia

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East Asia

• 1/5 of the world
• Includes eastern China, Japan, the Korean
  Peninsula, and Taiwan
• 5/6 live in China
• Most along the coast or along Huang and Yangtze
  Rivers
• 26 cities with more than 2 million, 52 with more
  than 1 millionstill 2/3 live in rural areas
• Most Japanese live in Tokyo and Osaka
• Most Koreans live in Seoul

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South Asia

• 1/5 of Worlds population
• Includes India, Pakistan, Bangladesh, and Sri
  Lanka
• ¾ live in India
• Mostly rural populations- ¼ live in urban areas

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Europe

• 1/9 of Worlds population
• Includes European section of Russia
• Over 4 dozen countries
• Unlike Asia, ¾ of Europeans live in cities
• Largest concentrations near coalfields of
  Germany, England, and Belgium
• Dont produce enough food for themselves import
  most of it

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Southeast Asia

• ½ billion people live here
• Mostly on islands b/w Indian and Pacific Oceans
• Java, Sumatra, Borneo, Papua New Guinea, and the
  Philippines
• Mostly farmers in rural areas
• Together the 3 Asian concentrations have more
  than half the Worlds pop., living on only 10 of
  the Earths land area

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Other Population Clusters

• Largest cluster in Western hemisphere is NE US
  and SE Canada
• Chicago to Boston to Newport News
• About 2 of World population
• Only 3 farmers
• Another 2 in West Africa
• Most in Nigeria
• Like Asia, mostly agriculture

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Sparsely Populated Regions

• Relatively few people live in areas where it is
  hard to grow food
• Too dry, too wet, too cold, or too mountainous
• Ecumene- portion of Earths surface occupied by
  permanent human settlement
• Has grown over time

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Dry Lands

• 20 of Earths land surface is too dry for
  farming
• Still may have valuable natural resources such as
  oil reserves
• Two largest desert regions are b/w 15 and 50
  degrees N lat. and 20 and 50 degrees S lat.

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Wet Lands

• Too much moisture can be inhospitable for humans
• Mostly b/w 20 degrees N and 20 degrees S latitude
  in South America, Central Africa, and SE Asia
• High rain and high heat lead to rapid depletion
  of soil nutrients
• If rains are seasonal, it may be possible to grow
  enough food to support a large population

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Cold Lands

• The poles are either covered in ice or
  permanently frozen (permafrost)
• Drier than most deserts small annual snowfall
  just never melts
• Cant grow food, therefore very few humans live
  in thee areas

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High Lands

• Highest mountains are steep, snow covered, and
  sparsely settled
• Exceptions------ people prefer higher ground if
  lower areas if temperature and precipitation are
  to high
• Ex. Mexico City
• One of the Worlds largest cities, and its at an
  elevation over 7000 ft.

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Population Density

• Aka arithmetic density- total of people divide
  by total land area
• Used to compare countries because the info. for
  computing is easy to obtain
• About 80 per sq. mile in US (31 per sq.
  kilometer)
• Bangladesh 2700 per sq. mile (many people, small
  land)
• India 900 (more people than US, less land)
• Canada 8 (big land, few people)
• Manhattan island-68,000

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continued

• Arithmetic density helps answer the where
  people live question
• To explain why people live where they do we
  need other measures

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Physiological Density

• Def.- the of people supported by a unit of
  arable land
• In US, 445 per sq. mile (172 p/sq. kilo.)
• In Egypt, its 6,682 sq. mi
• Therefore, 1 unit of arable land in Egypt must
  feed far more people than in the US
• The higher the physiological density, the greater
  pressure that people place on the land to produce
  enough food

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continued

• Comparing physiological and arithmetic densities
  helps geographers understand the capacity of the
  land to yield enough food for the needs of the
  people
• If the physiological density is much larger than
  the arithmetic density, much of the countrys
  land mass is unsuitable for agriculture

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95 of Egyptian population lives in the Nile
Valley and Delta
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Agricultural Density

• Def.- the ratio of the of farmers to the amount
  of arable land
• helps account for economic differences
• MDCs have lower agricultural densities because
  technology and finance allow a few people to farm
  extensive land area
• Allows pop. to work in other industries

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continued

• High physiological density paired with a low
  agricultural density means an that a country has
  an efficient agricultural system

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Natural Increase

• Three ways geographers measure pop. Change
• Crude birth rate (CBR) total of live births
  in a year for every 1,000 people alive in the
  society
• Crude death rate (CDR) total of deaths in a
  year for every 1,000 people alive in the society
• Natural increase rate (NIR) the growth of a
  population in a year, computed as the crude birth
  rate minus the crude death rate

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continued

• NIR for world is currently about 1.2
• All-time high was 2.2 in 1963
• About 80 million being added each year
• Highest ever was 1989 when 87 million people were
  added
• With current pop. level, a change of .01 in the
  NIR causes a huge swing in pop. growth

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continued

• The NIR affects the doubling time-
• The number of years needed to double the
  population, assuming a constant NIR
• At current rate, doubling time is 54 years
• If remains constant, pop. will reach 24 billion
  by 2100
• At peak NIR of 2.2 in 1963, pop. was doubling
  every 35 years
• At constant 2.2 rate, 2100 pop. Would be 50
  billion

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continued

• Almost 100 of natural increase is clustered in
  LDCs
• More than 2 in most of Africa, Latin America,
  and the Middle East
• Actually negative in Europe
• 2/3 of World pop. growth during past 10 years has
  been in Asia

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Fertility

• Total fertility rate (TFR) the average number
  of children a woman will have throughout her
  childbearing years (15-49)
• Attempts to predict the future behavior of
  individual women in a world of rapid cultural
  change
• TFR for world is 2.7
• Much higher in LDCs than MDCs
• Over 6 in some African countries

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Mortality

• Infant mortality rate (IMR)- the annual of
  deaths of infants under 1 year of age, compared
  with total live births
• Per 1000 births
• Very high in Africa, very low in Europe
• A reflection of the countrys health care system
• US has a higher IMR than Canada and Europe
• Many poor in US cant afford health care

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• Life expectancy- the average of years a newborn
  infant can expect to live at current mortality
  levels
• Higher in MDCs average late 70s
• Lower in LDCs- only 40s in most of Africa

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• NIR, CBR, TFR, IMR, and life expectancy
  distributions follow similar patterns
• More developed regions have lower NIR, CBR, TFR,
  and IMR with higher average life expectancy
• CDR does not follow this pattern
• The combined CDR is lower for LDCs than MDCs
• This is due to their stages in the process of
  demographic transition

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Demographic Transition

• Def.- the process of change in a societys pop.
  from a condition of high CBR and CDR and low NIR
  to a condition of low CBR and CDR, low NIR, and a
  higher total pop.
• 4 stages have been identified
• As a country moves from one stage to the next, it
  will never go back

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Demographic Transition
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Stage 1 Low Growth

• Most of human history fits this category
• CBR and CDR vary from year to year, but always
  remain high
• In effect they cancel out the possibility of pop.
  growth
• NIR basically zero

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continued

• Most were hunter/gatherers during this period
• Pop. would increase when there was an abundance
  of food, but would decrease when it was hard to
  come by
• About 8000BC the pop. began to grow by several
  thousand each year
• From about 5 mill. In 8000BC to 800 million in
  1750

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continued

• Agricultural revolution- when humans first
  domesticated plants and animals and no longer
  relied entirely on hunting and gathering
• There was now a more stable food supply, but it
  could still be unpredictable
• Therefore, stage1 continued because of things
  like war and famine
• No country still in this stage

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Stage 2 High Growth

• Soon after 1750 the World pop. grew 10 times
  faster than it had ever done
• In 1750 about ½ million people were added to the
  pop. In 1800 5 million were added
• Some countries moved into stage 2
• CDR plummets, while CBR remains high
• Leads to high NIR

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Continued

• Industrial revolution- a series of improvements
  in ind. technology that transformed the process
  of manufacturing goods
• Led to never seen before amount of wealth, which
  made some communities healthier places to live
• Machines helped farmers increase harvests and
  freed people to work in factories

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• Sanitation and personal hygiene were improved,
  sewers were installed
• People were healthier and lived longer
• European and NA countries entered stage 2 around
  1800
• Most African, Asian, and Latin American did not
  until 1950
• In 1900 8 million people were added, 2000 80
  million were added

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• The LDCs moved into stage 2 for different reasons
  than the MDCs
• Medical revolution- medical technology from
  Europe and US diffused to LDCs eliminating many
  causes of death and allowed people to live longer

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Stage 3 Moderate Growth

• CBR drops sharply, CDR slowly declines
• CBR still greater than the CDR, but NIR is not as
  high
• European and NA countries made the transition in
  the first half of the 20th century
• Most LA and Asian countries have recently moved
• Most African countries are still in stage 2

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• The sudden drop of the CBR is caused by a change
  in social customs
• People choose to have fewer children, they are
  more likely to live in cities and not on a
  farmmaking children an economic liability
  instead of an asset, and urban homes often dont
  have enough space for large families

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Stage 4 Low Growth

• CBR declines to the point where it equals CDR,
  and the NIR approaches zero
• Called zero population growth
• can occur when the CBR is slightly higher than
  the CDR because some females die before reaching
  childbearing years
• A TFR (total fertility rate) of 2.1 produces zero
  pop. growth (not counting immigration)

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continued

• Stage four countries can be identified by looking
  at a map of TFR
• In the US the TFR has moved slightly below zero
  population growth since 2000

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• Social customs again help explain the transition
• Women work outside the home, birth control is
  more accepted and more available
• Some European countries like Russia have negative
  NIRs (more deaths than births) blame it on the
  communistshigh pollution and unhappy people

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• Demographic transition is almost like a cycle
• Stage 1 little or no natural increase
• Stage 4 little or no natural increase
• 2 major differences
• Stage 1 CBR is high 35-40, stage 4 its low 10
• Total pop. Is much higher in stage 4

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Demographic Transition
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Population Pyramids

• The stage of demographic transition gives a
  country a distinctive population structure
• Demographic transition effects the structure in 2
  ways
• of population in each age group
• Distribution of males and females

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Continued

• Population pyramid- a bar graph representing the
  distribution of population by age and sex
• Pop. is broken down into 5 year age groups
• Men on the left, females on the right
• Shape determined primarily by CBR
• Stage 2 pyramid likestage 4 rectangular

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Age Distribution

• Dependency ratio- the of people who are to
  young or too old to work, compared to the number
  of people in their productive years
• The larger the of dependents, the greater the
  burden on the working pop.

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• The pop. Is divided in to three groups to compare
  dependency ratios
• 0-14
• 15-64
• 65 and older
• Group 1 and 3 are generally considered dependents

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• Stage 2 countries have about 50 dependents
• Stage 4 only about 33
• Makes the dependency ratio 11 in stage 2
  countries and 12 in stage 4
• Young dependents outnumber elderly 10 to 1 in
  stage 2about even in stage 4 countries

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Continued

• Stage 2 countries 1/3 of pop. is under 15
• Makes it hard for poorer countries to provide
  enough schools, hospitals, and daycares
• Stage 4 countries have a graying population
• US spends more than ¼ of budget on Social
  Security and healthcare for older Americans

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Sex Ratio

• Def.- the number of males per hundred females in
  the population
• Varies among countries
• In general, slightly more males are born, but
  they also have higher death rates
• In Europe in US it is 95100, it is 102100 in
  the rest of the world
• In US, males under 15 outnumber girls 105100
  until about age 40

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Malthus on Overpopulation

• Wrote An Essay on the Principle of Population in
  1798
• Claimed that the population was growing much
  faster than the food supply
• Pop. Growing geometrically, food supply only
  arithmetically
• Malthus wrote this several decades after England
  entered stage 2
• Believed pop. Growth would drain all countries of
  resources unless moral restraint was used to
  lower the birth rate or disease, famine and war
  raised the death rate

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Neo-Malthusians

• Argue that 2 char. of recent pop. growth make the
  theory even more scary
• Most pop. Growth is in poor countries that dont
  have many resources to begin with
• World pop. Growth is outstripping other resources
  besides food (ex. Energy)

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Malthuss Critics

• Viewed as unrealistically pessimistic because he
  assumed the worlds food resources as stable, not
  expanding
• Humans have the ability to adapt to the
  environment and sometimes adapt the environment
  (called _______________)
• Other critics argue that the World is better off
  with 6 billion people than 1 billion because of
  the economic development that has occurred

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Declining Birth Rates

• On a global scale Malthuss theory has not come
  true
• Food production has increased faster than the NIR
  since 1950
• NIR for the world declined in the 1990s from 1.8
  to 1.3
• Can only happen because of a rise in the CDR or a
  decline in the CBR

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Cont.

• The decrease in the NIR is largely the result of
  declining birth rates
• Has happened for two reasons
• Economic development
• Distribution of contraceptives

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Economic Development

• Wealthier communities have more money to spend on
  education and healthcare programs that lower
  birth rates
• If women go to school and learn employment skills
  they will have more economic control over their
  lives

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Distribution of Contraceptives

• In LDCs, demand for contraception is greater than
  the supply
• Which means if more are distributed, more will be
  used and birth rate will decline
• About ¼ of African women use contraceptives
• Economic, religious, and educational reasons for
  this

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World Health Threats

• In some countries high CDRs have resulted in the
  declining NIR
• Epidemiologic transition- distinctive causes of
  death in each stage of the demographic transition

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Epidemiologic Transition Stages 1 and 2

• Stage one has been called the stage of pestilence
  and famine
• Infectious and parasitic disease were principal
  causes of human death
• Ex. Black Plague
• Stage 2 has been called the stage of receding
  pandemics
• A disease that occurs over a wide geographic area
  that affects a very high proportion of the
  population
• Can be reduced by improved sanitation, nutrition,
  and medicine

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continued

• Death rates didnt decline immediately in stage 2
  after industrialization
• The working poor lived in overcrowded slums had
  high death rates
• Ex. Cholera

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Epidemiologic Transition Stages 3 and 4

• Stage 3 is known as the stage of degenerative and
  human-created diseases
• Decrease in deaths from infectious diseases and
  an increase in chronic disorders associated with
  aging
• Stage 4 known as the stage of delayed
  degenerative diseases
• Medical advances allow people to live longer even
  with degenerative diseases

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Epidemiologic Transition Possible Stage 5

• Some argue for a stage of reemergence of
  infectious and parasitic diseases
• 3 reasons for possible reemergence
• Evolution of microbes
• Poverty leads to sub-par medical care
• Improved travel

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continued

• Ex. Avian Flu
• Only a modest change in its makeup would make
  humans very susceptible
• Would become a pandemic
• AIDS
• 20 million have died and 40 million are infected
  worldwide
• Mostly effects LDCs now
• 25 million in sub-Saharan Africa

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