Population Geography Counting the Worlds Population

Population Geography

Counting the Worlds Population

Bacteria Bottles

John Madden - 2009/10

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.

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?


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)


Bacteria BottlesReady 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?


Bacteria Bottles

3) With space resources quadrupled, the bacteria have two more doubling times, or two minutes before they will run out of space.

11:58 p.m. : Bottle 1 is one-quarter full.

11:59 p.m. : Bottle 1 is half-full. 12:00 a.m. : Bottle 1 is full. 12:01 a.m. : Bottles 1 and 2 are full. 12:02 a.m. : Bottles 1, 2, 3, and 4 are

full


Bacteria Bottles

So, what does this suggest about Human Population Growth??


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Bacte

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Bacte

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Human Population Growth!

Year


Why study population?

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

Demography: the study of human populations 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 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

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

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 East Asia: China, South and North Korea and

Japan 1.5 billion people with 1.3 billion in China

South Asia: India, Pakistan and Bangladesh 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

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 Equations exist to allow demographers to determine actual

populations Demographic accounting equations

Global population accounting equation P1=P0+B-D

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

Subglobal population accounting equation P1=P0+B-D+I-E

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

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+10,000-5,000= 1,030,000 people

Population Pyramids 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

Did Algeria’s growth rate decrease? How can you tell? What happened to Italy’s population? Graying population: when a population has more middle-

aged and older people than young people. Why is this a problem?

South Africa and the United States

Fertility and Mortality

Fertility: reproductive behavior of a population Impacted by

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

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 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 TFR has declined on every continent but Africa over the last 50 years

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 RatesCountry 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

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

Defined: time that it takes for a population to double

Equation: Divide 70 by current growth rate of population 70/ current growth rate = doubling time

Examples 70/5% = 14 years 70/2% = 35 years

Population Consequences

The good AND the bad!

A Graying Population

What would be the positives and negatives of a graying population?

Dependency ratio: show relationship between dependents and nondependent's 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 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 Carrying capacity: number of people an area can

sustain or support Japan: imports food Saudi Arabia: desalinizes water to increase carrying

capacity Overpopulation: when a region’s population

outgrows its carrying capacity 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 In China, boys now outnumber girls 119 for

every 100 girls born – natural average 105 to 100

Population growth theories Thomas Malthus

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

Is population growth a problem?

Two very different, but supportable ideas

Yes Most of our increased food

availability is tied to non-sustainable resources like oil

Humans bring about environmental destruction I=PAT Environmental Impacts=

Population size times affluence times technology

Most humans live a lifestyle that is not sustainable

No 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

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

10,000-12,000: first agricultural revolution 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 Industrial revolution was new technologies and industries-

started in England Move people into cities

Second industrial revolution improved fertilization and food storage increasing food supply Allowed more people in cities because extra food is grown

can be sold in cities

What causes population growth? Medical Advances

Inoculations, better health care, new medications Quantity and quality of food

Agricultural technology has increased availability and health benefit of food

Ethnic and religious issues Many cultures forbid birth control or abortion Some cultures have beliefs that spread disease

Economic issues Agricultural base economy=higher birth rate Industrial or service base=low or no population growth

Population Projections for the Future Different growth scenarios

exist Medium growth (most

accepted) 2050=9 billion; 2100=9.5

billion Low-growth

Population will begin declining: 2050=7.5 billion; 2100=5.1 billion

High-growth scenario 2050=11 billion; 2100=16

billion

Demographic Transition Model 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)

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) 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) 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)

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

Based on England's transition from subsistent economy to industrialized society

All countries may not pass through this system 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 Germany-something that shows the graying population but what else will happen?

Demographic Momentum

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

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 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

Pro-natalist policies promote reproduction and bigger families-sometimes called expansive policies 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 rates-sometimes calls restrictive policies Examples include easily accessible abortions and

contraceptives, or government policies limiting children Examples include India and China

Global population control

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

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 space-time compression

Spatial interaction is the interconnectedness of two places

Migration: permanently moving from home region and crossing an administrative boundary

Why do people migrate?

Migration stream is pathway from a place of origin to a destination Many develop because of information exchange between

people Usually found with migration counter stream

Push factors: reasons people leave a place Examples: high taxes, high crime rates and abusive

governments Pull factors: reasons people go to a new place

Place desirability: possession of positive features making people want to move there Examples: affordable real estate, being near family member,

good schools

Voluntary vs. Forced MigrationVoluntary Migration 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 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 Sometimes called internally displaced peoples

Brief history of migration 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 Before 1840 England, 1840-1850’s German and Irish

20th century 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

Defined: movement within a country Interregional migration

Moving from region in the country to another region

Intraregional migration Moving within a region, such as from a city to a

suburb Urban migration

Migration from farms to cities

Migration Selectivity 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 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” Late 1800s, British geographer Ernst Ravenstien

identified 11 generalizations about migration-some still apply today

The majority of migrants travel short distances 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.

Migrants who are traveling a long way tend to move to larger cities than smaller cities 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 True in Ravenstein’s time because of industrial revolution Seen in many developing countries like China and Brazil

Last two “Laws”

Families are less likely to migrate across national borders than are young adults It is easier for single people to migrate than whole families Singe people less encumbered with responsibilities

Every migration stream creates a counter stream 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

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.

Documents

Population Geography Counting the Worlds Population