Transcript Population Geography

Population Geography
Counting the Worlds Population
Bacteria Bottles
A Lesson In Exponential Growth!
This puzzle illustrates the concept of
exponential growth using bacteria. Bacteria
multiply by division. One bacterium
becomes two. Then two divide into four;
the four divide into eight, and so on. For a
certain strain of bacteria, the time for this
division process is one minute. If you put
one bacterium in a bottle at 11:00 p.m., by
midnight the entire bottle will be full.
John Madden - 2009/10
Bacteria Bottles
1)When will the bottle be half-full?
How do you know?
2) Suppose you could be a bacterium
in this bottle. At what time would
you first realize that you were
running out of space? Why?
John Madden - 2009/10
Bacteria Bottles
Suppose that at 11:58 some bacteria realize that they are running out
of space in the bottle. So they launch a search for new bottles.
They look far and wide (working at the speed of light).
Finally, offshore in the Arctic Ocean, they find three new bottles!
Great sighs of relief come from all the bacteria. This is three times
the number of bottles they’ve ever known. Surely, they think, their
space problems are over.
3) Is that so? Explain why the bacteria are still in trouble. Since their
space resources have quadrupled, how long can their growth continue?
(Remember it takes an hour to fill up the first bottle)
John Madden - 2009/10
Bacteria Bottles
Ready For The Answers???
1) The bottle will be half-full at
11:59 p.m. because the doubling
time is one minute and the bottle
will be full at midnight.
2) At 11:55 p.m., when the bottle
was only 3% full and 97% empty,
would it be easy to perceive that
there was a space problem?
John Madden - 2009/10
Bacteria Bottles
3) With space resources quadrupled, the bacteria
have two more doubling times, or two minutes
before they will run out of space.
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11:58 p.m.
:
Bottle 1 is one-quarter full.
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11:59 p.m.
:
Bottle 1 is half-full.
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12:00 a.m.
:
Bottle 1 is full.
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12:01 a.m.
:
Bottles 1 and 2 are full.
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12:02 a.m.
:
Bottles 1, 2, 3, and 4 are full
John Madden - 2009/10
Bacteria Bottles
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So, what does this
suggest about
Human Population
Growth??
John Madden - 2009/10
Bacteria Bottles
John Madden - 2009/10
Bacteria Bottles
John Madden - 2009/10
Year
John Madden - 2009/10
Bacteria Bottles
Human Population Growth!
Why study population?
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Over the last 12,000 years of history,
population is increasing faster than ever
before!
In the last 2000 years, the Earth’s population
has increased 10 times
In the last 50 years, Earth’s population has
doubled
Will this population growth increase to a level
that will cause a global crises?
Population Basics
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Demography: the study of human populations
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Currently 7 billion people on the Earth
This study is very important because the number of people
in a country can influence the infrastructure and support
systems of a country
Population Equation
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Scale of inquiry: size of a geographic investigation (world,
regional or local) important to understand
On global scale, demographers focus on where earth’s
populations are increasing fastest and where they are
expanding more slowly-least stable areas experiencing the
fast growth
Population Facts
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About 81% of earth’s population lives in poorer, less
developed countries
The only two countries to have more than 1 billion
people are India and China
1 in 3 of earth’s people live in China or India
Nearly 3 of every 5 people live in Asia and Europe
Largest population concentration is East Asia-nearly
25% of earth’s total population: most people
subsistent farmers
Third largest population cluster is Europe: most
people are urban dwellers
Population Distribution and
Density
Population Distribution
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Defined: pattern of people across the earth’s
surface-where they live
Over history, people have been unevenly
distributed-Why?
Few people live in desert/tundra
About 75% of global population lives on 5%
of worlds surface
Area people can live is called the ecumene
50% of earth’s people live in cities
Worlds Population Density
http://en.wikipedia.org/wiki/List_of_countries_by_population_density
World Areas of Population Density
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East Asia: China, South and North Korea and
Japan
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South Asia: India, Pakistan and Bangladesh
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1.5 billion people with 1.3 billion in China
Within 50 years, India will pass China as most populace
country on planet
Southeast Asia: Vietnam, Indonesia and Thailand
Western and Central Europe: mostly urban
Northeastern United States and Canada: includes
megalopolis from Boston to Washington D.C.
Population Density
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Defined: number of people in a particular land area
Arithmetic density
 Total number of people divided by total land area
 Example: Egypt has arithmetic density of 177 people per square
mile but only 98% of population lives on 3% of land
Physiological density
 Number of people per unit of arable land
 Helps in analyzing amount of farmland available to population
 U.S. physiological density is 340 people per square mile; Japan
is 7,000 people per square mile; Egypt's is 3,000 people per
square mile
Agricultural density
 Number of farmers per unit of arable land
 High density meant many farmers are on each piece of farmland;
low density suggests the presence of larger farms
Population Math
Adding up population numbers
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Equations exist to allow demographers to determine actual
populations
Demographic accounting equations
 Global population accounting equation
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P1=P0+B-D
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Subglobal population accounting equation
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P1=P0+B-D+I-E
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P1 is size of population at end of interval of measurement
P0 is size of population at start of interval of measurement
B is number of births during interval of measurement
D is number of deaths during interval of measurement
P1, P0, B and D same as above
I is number of immigrants moving into region during interval of
measurement
E is number of emigrants moving out of region during interval of
measurement
Immigration: people moving into a region/country
Emigration: people leaving a region/country
Math Example
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Country A has 1 million people in 1990. Over
the next 10 years 75,000 babies are born;
50,000 people die; 10,000 people move into
the country; and 5,000 people exit. What
would the population be in 2000?
P1=1,000,000+75,000-50,000+10,0005,000= 1,030,000 people
Population Pyramids
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Also known as age-sex structures used to
evaluate the distribution of ages and genders in
a given population
Shows sex ratio (number of males compared to
females in a population) at ANY GIVEN TIME!
Cohorts (people of the same age) are split
between men and women on the pyramid
Used to analyze population and/or predict future
population
Cannot determine country size from pyramids
but can determine placement in DTM
Population Pyramid
Algeria’s pyramid has a wide base and a flattened top. What
does that mean?
Italy’s pyramid is wider in the middle than at the base. What
does that mean?
What expectations do you have for a population pyramid from
2025?
Expanding Populations
Stable Population
Contracting
Population
2025 Predictions
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Did Algeria’s growth rate decrease? How can you tell?
What happened to Italy’s population?
Graying population: when a population has more middleaged and older people than young people. Why is this a
problem?
South Africa and the United States
Fertility and Mortality
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Fertility: reproductive behavior of a
population
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Impacted by
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Fecundity of population
Diet and nutritional intake
Economic and industrialization levels
Sociocultural factors like age of marriage
Mortality: death related behavior of a
population
Population Key Terms
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Crude Birth Rate (CBR): number of live births per 1,000 people in
a year
Crude Death Rate (CDR): number of deaths per 1,000 people in
a year
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LDC’s average CDR of 20 while MDC’s average CDR of 10
Infant mortality rate (IMR): number of infant (children who die
before their first birthday) deaths per 1,000 live births
Life expectancy: average number of years to be lived by a
person
Fecundity: ability of a woman to conceive (usually 15 to 45)
General fertility rate (GFR): number of births per 1,000 women in
the fecund years
Total fertility rate (TFR): predicted number of births a woman will
have as she passes through fecund years
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TFR has declined on every continent but Africa over the last 50 years
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Example : in 1975 Mexico’s TFR was 7 but in 2009 had dropped to 2.37 – in China in 1970
TFR was 6 but 1.6 in 2009
2006 TFR rate was greater than 3.0 across the globe
2006 TFR rate in U.S., Europe and China was 2.1 or less
Fertility Rates
Country
Growth
Rate %
Per Year
Birth Rate
per 1,000
Death
Rate per
1,000
United
States
0.883
14.6
8.25
Japan
0.139
7.87
9.26
China
0.629
13.71
7.03
Russia
-0.474
11.03
16.06
Australia
0.801
11.90
7.62
Mexico
1.142
20.04
4.78
South Africa
-0.501
17.71
22.70
India
1.578
22.22
6.40
United
Kingdom
0.276
10.65
10.05
Replacement-Level Fertility
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A TFR of 2.1 is considered replacement-level fertility meaning
parents will produce the number of children needed to replace
themselves
TFR of 2.1 causes zero population growth (ZPG)
Rate of Natural Increase (RNI) is growth rate of a population
using the formula
 CBR-CDR/10
 Does NOT include immigration and emigration
RNI that equals zero means population won’t grow or decline
Global RNI in 2006 was 1.2%
More developed countries had an RNI of 0.1%
Less developed countries had an RNI of 1.5%
Africa’s RNI in 2006 was 2.3%
RNI does NOT include migration
Population Graph Options:
S-curves and J curves
Rule of 70
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Defined: time that it takes for a population to
double
Equation: Divide 70 by current growth rate of
population
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70/ current growth rate = doubling time
Examples
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70/5% = 14 years
70/2% = 35 years
Population Consequences
The good AND the bad!
A Graying Population
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What would be the positives and negatives of a
graying population?
Dependency ratio: show relationship between
dependents and nondependent's
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Dependents: people who depend on workers for survival
Nondependent's: people who can support themselves
through work
High ratio means more people are dependent than
working
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Fewer people to pay taxes
Social security dependency
2000 was first time in history that people under 14 years of
age were outnumbered by people over 60
Carrying Capacity and Overpopulation
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Carrying capacity: number of people an area can
sustain or support
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Japan: imports food
Saudi Arabia: desalinizes water to increase carrying
capacity
Overpopulation: when a region’s population
outgrows its carrying capacity
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Resource availability very important but resources can be
indigenous or imported
Some areas have resources to produce more than they
harvest-lack of infrastructure, political/economic stability,
etc.
Other population growth
consequences
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In China, boys now outnumber girls 119 for
every 100 girls born – natural average 105 to
100
Population
growth
theories
Thomas Malthus
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Wrote An Essay on the Principle of Population, 1798
 Argued that global population was growing exponentially while
food supplies were growing arithmetically
 Advocated birth control and celibacy (positive checks) and
warned of war, starvation and disease (negative checks)
 Said population growth caused poverty, crime and misery
Karl Marx
 Said population wasn’t problem-the problem was unequal
distribution of resources and wages
 Said population growth was caused by poverty and unequal
distribution so if things were distributed evenly, population
wouldn’t grow
Ester Boserup
 Believed overpopulation problem could be solved by increasing
number of subsistence farmers because when humans are faced
with starvation, they WILL develop new technology
Neo-Malthusians
 Argue that sustainable development hinges on Malthusian idea
that human population must reach a “sustainable” level within
carrying capacity
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Is population growth a problem?
Two very different, but supportable ideas
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Yes
 Most of our increased food
availability is tied to nonsustainable resources like
oil
 Humans bring about
environmental destruction
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No
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I=PAT
Environmental Impacts=
Population size times
affluence times technology
Most humans live a lifestyle
that is not sustainable
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Food supplies have
increased - in 1970
average caloric intake was
2,435 but in 2000 average
was 2,087
Countries like China have
industrialized quickly
BECAUSE of increased
population that create
workers and a market
Humans are the ultimate
resource and will continue
to advance to support
ourselves
Historical Growth
The DTM
Population Explosion
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Over last three centuries, earth has experienced a
population explosion
Currently population is growing at exponential rate
Exponential growth: the more people that are
added, the faster the population is growing
Linear (a.k.a. arithmetic) growth: constant fixed rate
of growth
In 1750 world population was 700 million
In 200 years (1950) population grew to 6 billion
Historical population growth
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10,000-12,000: first agricultural revolution
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Humans domesticated crops
Led to development of cities and stationary settlements
City development leads to population growth
1700’s Industrial Revolution and second agricultural
revolution
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Industrial revolution was new technologies and industriesstarted in England
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Move people into cities
Second industrial revolution improved fertilization and food
storage increasing food supply
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Allowed more people in cities because extra food is grown can
be sold in cities
What causes population growth?
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Medical Advances
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Quantity and quality of food
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Agricultural technology has increased availability and
health benefit of food
Ethnic and religious issues
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Inoculations, better health care, new medications
Many cultures forbid birth control or abortion
Some cultures have beliefs that spread disease
Economic issues
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Agricultural base economy=higher birth rate
Industrial or service base=low or no population growth
Population Projections for the Future
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Different growth scenarios
exist
Medium growth (most
accepted)
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Low-growth
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2050=9 billion; 2100=9.5
billion
Population will begin
declining: 2050=7.5 billion;
2100=5.1 billion
High-growth scenario
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2050=11 billion; 2100=16
billion
Demographic Transition Model
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Defined: DTM predicts changes in birth,
death and natural increase rates in countries
as they transition or mature
Based on assumption that economics drive
demographic change and that all countries
will pass through five stages of demographic
transition or change
The three measurements in the model are
CBR, CDR and RNI
Stage 1: Low Growth (high stationary
stage)
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Hunter and Gatherer
Societies
High CBR and CDR leading
to low RNI
Fluctuation in CBR and
CDR because of disease,
famine and war
Usually characterizes a
subsistence farming country
without industrialized
economy
Stage 2: High Growth (Expanding Stage)
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Agricultural Societies
High CBR: children are still
needed on the farms to help
Declining CDR: CDR starts to
drop as new health care
systems arrive-industrialization
has begun but CBR has not
fallen because children still
seen as economic necessity
RNI increases because same
high number of births is
occurring with fewer deaths to
match the high birth numbers
Population expansion is high
Stage 3: Moderate Growth (expanding
stage)
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Industrial Societies
Declining CBR
CBR drops because families’ decisions to lower number of children they are
having
RNI is decreasing but still greater than zero so population is still expanding
Stage 4: Low Growth (low stationary
stage)
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Tertiary Societies
CBR and CDR meet at equal levels (equilibrium) but this time they are at low
levels
RNI is low
Seen as modern society stage with zero population growth
Criticisms of DTM
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Based on England's transition from subsistent
economy to industrialized society
All countries may not pass through this system
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Some African countries received medicines and food from
more developed countries
England took 100 years to go from stage 2 to 3 and
countries today are being pushed at a much faster rate
We don’t know exactly where the 5th stage is
headed. It includes a decline in the CBR as seen in
modern countries like France and Germanysomething that shows the graying population but
what else will happen?
Demographic Momentum
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Also known as hidden momentum
Occurs in many developed countries when
population continues to grow even after
replacement-fertility is reached
Happens when people live longer-even
though TFR is 2.1 to 2.5 population is still
growing because people are dying at slower
rates
Makes zero population growth difficult to
attain
Global DTM
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All countries on globe are out of stage 1
Most Latin American and Asian countries are
in stage 3
Most African countries remain at high growth
in stage 2
Many Europeans at end of stage 4
Japan, Germany and France are facing a fifth
stage or the graying population problem
Checks on Population
Public and Private
Negative Checks on Population
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Three basic categories: natural disasters, war or political turmoil
and economic issues
Black Plague: killed 40% of European population and 13 million
Chinese in 1300s
Irish potato famine: killed almost 50 percent and caused
massive emigration
HIV/AIDS: since 1980s has risen to pandemic (disease affecting
very large amounts of people in large area) levels
 In 2005, 39 million people living with HIV, nearly 3 million died
from AIDS
 In Sub-Saharan Africa, 19% of all adults are infected
 China expected to see nearly 11 million infections by 2010
 More than ½ of 5 million new cases every year are people ages
15-24
 In 2010 were 25 million AIDS orphans
Global HIV/AIDS Rates
Population Policies
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Pro-natalist policies promote reproduction and
bigger families-sometimes called expansive policies
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Examples include tax breaks for children or antiabortion
laws
Found in Europe, 1950s China and modern United States
Also found historically and in susbistent type economies
Anti-natalist policies discourage high fertility ratessometimes calls restrictive policies
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Examples include easily accessible abortions and
contraceptives, or government policies limiting children
Examples include India and China
Global population control
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1984 UN population conference held in Mexico influenced by
new technologies to increase global food production and China’s
recent enactment of one-child policy
1994 conference in Egypt proposed the Cairo Strategy-Teaching
contraceptive uses in schools in poorer countries
 Cairo Strategy has been very controversial with certain
conservative groups
2004 conference declared the key to limiting population growth is
to empower women through education and economic parity
(equality)
Population Movement
a.k.a. Migration
Population Movement
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In the modern world, friction of distance
(difficulty of distance) has been reduced
Process of coming together even though
distances are not decreasing is called spacetime compression
Spatial interaction is the interconnectedness
of two places
Migration: permanently moving from home
region and crossing an administrative
boundary
Why do people migrate?
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Migration stream is pathway from a place of origin to
a destination
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Push factors: reasons people leave a place
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Many develop because of information exchange between
people
Usually found with migration counter stream
Examples: high taxes, high crime rates and abusive
governments
Pull factors: reasons people go to a new place
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Place desirability: possession of positive features making
people want to move there
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Examples: affordable real estate, being near family member,
good schools
Voluntary vs. Forced Migration
Voluntary Migration
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Occurs when migrants have
an option of whether or not
to move
Usually not associated with
violence or abusive
governments
Example: a new job,
moving to be near family
Forced Migration
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Emigrants pushed from land
Refugees: migrants fleeing
some form of persecution or
abuse
International refugees: fell
country to move to another
country
Intranational refugees:
abandon homes but remain
in their country to escape
persecution
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Sometimes called internally
displaced peoples
Brief history of migration
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About 3% of worlds people have migrated from their countries of
origin
North America, Oceania and Europe have net immigration
Asia, Africa and Latin America have net emigration
50% of Southwest Asia’s population are immigrants
U.S. had three major waves of immigration
 Colonial era (1607-1776) primarily from Europe and Africa and
was both voluntary and involuntary
 19th century primarily from Europe
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Before 1840 England, 1840-1850’s German and Irish
20th century
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1907 northern and western Europe and Russia; 1970-1980’s Asia
leading source of immigrants, 1980’s Latin America primary source
Immigration altered by Quota Act of 1921 which allowed highest
number of immigrants from European countries and discriminated
against Asians and other regions
8 Great Migrations (KNOW THESE!)
Internal Migration
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Defined: movement within a country
Interregional migration
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Intraregional migration
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Moving from region in the country to another
region
Moving within a region, such as from a city to a
suburb
Urban migration
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Migration from farms to cities
Migration Selectivity
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Often, migration fits into a pattern based on age,
income and other socioeconomic factors
Defined: evaluation of how likely someone is to
migrate based on personal, social and economic
factors
Most influential factor is age
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Most people move 12 times in their lifetimes, ½ before age
25
Brain Drain: net out-migration from one place of
most educated workers who leave for more
attractive places
Guest Workers: people let into a country to work
jobs native people don’t necessarily want to do like
heavy, dangerous or disagreeable work
Ravenstein’s Migration “Laws”
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Late 1800s, British geographer Ernst Ravenstien
identified 11 generalizations about migration-some
still apply today
The majority of migrants travel short distances
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Step migration: person has a long distance goal in mind
and achieves it in a series of small steps
Intervening opportunity: when an opportunity is found along
destination that journey is stopped
Intervening obstacles: barriers in migration journey like
financial problems, roadblocks, immigration requirements
and wars
Ravenstein’s “Laws”, cont.
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Migrants who are traveling a long way tend to move
to larger cities than smaller cities
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Large city has more opportunities creating an almost
magnetic pull
Keep in mind, Ravenstein was writing during height of
industrial revolution
Rural residents are more likely to migrate than are
urban residents
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True in Ravenstein’s time because of industrial revolution
Seen in many developing countries like China and Brazil
Last two “Laws”
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Families are less likely to migrate across national
borders than are young adults
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It is easier for single people to migrate than whole families
Singe people less encumbered with responsibilities
Every migration stream creates a counter stream
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Net migration is the number of people in the original flow
minus the number of people in opposite flow (counter
stream)
Caused by many factors
Example: Jews leaving Germany before WWII who were
captured at borders and forced to return or young boy from
rural setting who moves to city and then returns to rural
area after trying city life
Chain Migration
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Occurs when people migrate to be with other
people who migrated before them and with
whom they feel some tie
Tie can be religious, familial, cultural, ethnic
or any type of connection
Most common type of migration to the U.S.