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Chapter 2: Population

http://www.ted.com/talks/hans_rosling_on_global_population_growth.html

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Why is Population Increasing at Different Rates?

Demographic Transition Model

Figure 2-15

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Demographic Transition• Countries that don’t fit the model: negative

growth (Ukraine)• Applicability of the demographic transition

to third world populations– Different economic situations– No migration escape hatch for LDCs (“massive

exodus” from Europe during the 19th century)– LDC populations are larger, denser, faster-

growing– Hidden momentum of young age-sex pyramids

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Demographic Momentum (hidden momentum)

• Occurs in an age structure with a large base and small top

• Very few elderly at the top of pyramid are available to die

• Many children who will soon be in peak reproductive ages (reproducing age 19-49)

• Compare the large number of children being born to the small number of elderly dying

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Why Is Population Increasing at Different Rates?

• Demographic transition & world population growth– Most countries = stage 2 or stage 3 of the

Demographic Transition• Stages 2 and 3 are characterized by significant

population growth

– No country is in stage 1 of the demographic transition

– It is easier to cause a drop in the CDR than in the CBR

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World Health ThreatsEpidemiologic Transition

Stage 1: Pestilence and famine–The Black Plague–Pandemics

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• An epidemic is a rate of unexpectedly high disease transmission--caused by something like a new vector, mutation of the disease, or favorable conditions for transmission or infection. H1N1 was an epidemic because it was fairly virulent and more people got it than would be expected in a "normal" flu season.

•  Pandemic is a big epidemic--there isn't a strict definition of when an epidemic is big enough to become a pandemic, but usually at the continental scale if not world scale.

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World Health Threatsthe epidemiologic transition

• Stage 2: Receding pandemics

Cholera and Dr. John Snow

Figure 2-31

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World Health ThreatsThe epidemiologic transition

• Stage 3: Degenerative diseases

–Most significant: Heart disease and cancer

• Stage 4: Delayed degenerative diseases

–Medical advances prolong life

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World Health Threatsthe epidemiologic transition

• A possible stage 5: Reemergence of infectious diseases?

–Three reasons why it might be happening:

»Evolution

»Poverty

»Improved travel

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The Most Lethal Infectious Disease: AIDS

Figure 2-33

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Overpopulation, Malthus, and Neo- Malthusians

“The capacity of Earth to produce food and support people is finite.”

- Anne & Paul Erlich

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Thomas Robert Malthus

• British political economist, demographer and Reverend

• Wrote An Essay on the Principle of Population in 1798

http://www.youtube.com/watch?v=r1ywppAJ1xs&feature=player_embedded

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In response to Utopians….

• Argued that population increased geometrically while food supply increased arithmetically

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Thomas Robert Malthus

• Arithmetic increase: when a series of numbers increases or by adding the same number

• Geometric increase: when a series of numbers increases by being multiplied by the same factor

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Criticisms of Malthus

• Pessimistic viewpoint• Assumes population growth causes

problems, while it can bring economic growth and advancement

• Marxist critique – social problems result from unjust economic structure, not population problems

• Engels critique – Malthus’ theory was based on capitalism, if resources were shared equally, earth could sustain a much larger population

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Criticisms

• Malthus did not account for technological advancements that could increase food output

• Malthus did not account for cultural/economic factors that bring countries to stages 3 and 4 of DTM

• Malthus over-predicted the population growth

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Malthus: Theory & Reality

Figure 2-25

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Declining Birth Rates

Reasons for declining birth rates

• Reliance on economic development

• Distribution of contraceptives

– Reducing birth rates with contraception

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Family Planning

Figure 2-30

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Neo-Malthusians

• Share Malthus’ concern for population growth

• Argue that Malthus thought only wealthy countries would enter periods of high population growth (Stage 2 of DTM)

• Argue world population growth is outpacing many resources, not just food

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Began with this statement…

• The battle to feed all of humanity is over. In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now. At this late date nothing can prevent a substantial increase in the world death rate ...

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• humanity could not prevent severe famines, the spread of disease, social unrest, and other negative consequences of overpopulation.

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The Population Bomb

• Published in 1968

• Launched worldwide debate and spurred along environmental movement

• Was received with much skepticism about its argument and predictions

• In 1968 world population was 3.5 billion, 40 years later it was 6.7 billion

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What it got right….• Drew attention to the “over-consumption

problem”• Expressed concern over the seas’ bounty• Predicted high-yield grains were best

option for meeting the world’s hunger• Expressed concern over the

environmental effects of the “Green Revolution”

• Predicted threats of new epidemics

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What it got wrong…

• Did not account for the number of and increase in greenhouse gas emissions

• Too optimistic about consumption: while population nearly doubled, consumption nearly tripled

• Underestimated environmental impact of “Green Revolution”

• Incorrectly predicted that the Baby Boomers would continue high birth rates of their parents

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Key Issues

• Where is the world’s population distributed?

• Where has the world’s population increased?

• Why is population increasing at different rates in different countries?

• Why might the world face an overpopulation problem?

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• “As U.S. birth rate drops, concern for the future mounts”– U.S. fertility rate fell below replacement

level (1.9)• Deep recession and slower immigration

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• “The Islamic World’s Quiet Revolution”

• “The Fertility Implosion”– “Over the past three decades the Arab

world has undergone a little noticed demographic implosion. Arab adults are having fewer kids.”