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Published byTobias Morris Modified over 9 years ago
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World Population Dynamics
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I. The Population Explosion
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A. The Population Explosion MDC’s 1.Last 200 years for MDC’s (Most Developed Countries) – – Industrial Revolution – – improvements in sanitation & medicine LDC’s 2.Last 50 years or less for LDC’s (Least Developed) – – transfer of technology: medical & agricultural
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World population increase has been a result of declining death rates, NOT increasing birth rates
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Population Assumption: pop. growth will hit ZGP at about 10 billion…otherwise 1 trillion people by 2300
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B. THE DEBATE: - The entire human pop. could fit into Delaware - The whole world could live in single story houses in Texas THE DEBATE: carrying capacity carrying capacity… the maximun population that an area can support on a continuous basis withou experiencing unacceptable deterioration how many people are too many??? Population Doubling Times: 1804 – first billion 1927 – second billion 1974 – third billion 2000 – 6 billion
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C. Sir Thomas Robert Malthus (1766-1834) - An English Economist & Demographer Malthus stated (1789): 1. 1.Population is limited by subsistence: *populations grow faster than food production 2.Population increases with subsistence 3.Checks are either “private” or “destructive”: War Poverty Pestilence (disease) Famine 4. He thought pop. Would grow geometrically while food would increase arithmetically.
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D. Destructive Checks: Limits on Population Growth: 1. Starvation: - 50 people die of starvation every minute - 50% are less than 5 years old 2. War: - about 70 million people die every year 3. Epidemics & plagues: - limited population growth mostly in past - famines in India (1943), Ethiopia (1980’s)
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E. The Great Population Debate Cornucopians vs. Neo-Malthusians: “Cornucopian” Viewpoint: − technology raises carrying capacity S-curve − S-curve, NOT J-curve − resources are viewed as infinite − people are the world’s ultimate resource Julian Simon claimed in 1994: "We now have in our hands - in our libraries really - the technology to feed, clothe, and supply energy to an ever- growing population for the next 7 billion years."
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The “S”-curve
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Are you a Cornucopian or Neo-Malthusian??? 1. Are humans the cause of environmental problems? 2. Can we some day colonize the moon or outer space? 3. Are humans parasites on the face of the Earth? 4. Are the possibilities of human ingenuity infinite? 5. When is too many too many?
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Malthusian Theory & Reality Work of Vaclav Smil: Malthus was fairly close on food production but much too pessimistic on population growth. Many people in the world cannot afford to buy food or do not have access to sources of food… BUT these are problems of distribution of wealth NOT insufficient global production of food
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Why do women in some parts of the world have more babies than those in other parts of the world? II. Factors Affecting Fertility
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A. Economic Factors 1. Agrarian societies: children are assets 2. Industrial societies: children are liabilities 3. Level of development: smaller family size= higher standard of living
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B. Social Factors 1. “traditional” role of woman (child-bearer) 2. children to care for elderly 3. male preference 4. high infant mortality rate 5. low literacy rates 6. lack of birth control 7. Religion: Catholicism, Islam, Hinduism
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C. Political factors 1. Anti-natal policies: -China (“One-Child Policy”) & India 2. Pro-natal policies: - China 1950-60’s - pop. implosion fears (Italy, Russia)
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Demographic momentum: this is the tendency for growing population to continue growing after a fertility decline because of their young age distribution. This is important because once this happens a country moves to a different stage in the demographic transition model. Demographic regions: Cape Verde is in Stage 2 (High Growth), Chile is in Stage 3 (Moderate Growth), and Denmark is in Stage 4 (Low Growth). This is important because it shows how different parts of the world are in different stages of the demographic transition. J-curve: This is when the projection population show exponential growth; sometimes shape as a j-curve. This is important because if the population grows exponential our resource use will go up exponential and so will our use as well as a greater demand for food and more. S-curve- traces the cyclical movement upwards and downwards in a graph. So named for its shape as the letter "s" Relates to growth and decline in the natural increase. Overpopulation- relationship between the number of people on Earth, and the availability of resources Problems result when an area’s population exceeds the capacity of the environment to support them at an acceptable standard of living. Underpopulation- it is the opposition to overpopulation and refers to a sharp drop or decrease in a region’s population Unlike overpopulation, it does not refer to resources but to having enough people to support the local economic system. If there are not enough tax payers, then the area cannot continue.
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Epidemiological transition (model): essentially the same thing as the demographic transition, however it specifically denotes a human phase of development witnessed by a sudden and stark increase in population growth rates brought about by medical innovation in disease or sickness therapy and treatment, followed by a re- leveling of population growth from subsequent declines in procreation rates.
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