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Human Population: Growth, Demography and Carrying Capacity

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Presentation on theme: "Human Population: Growth, Demography and Carrying Capacity"— Presentation transcript:

1 Human Population: Growth, Demography and Carrying Capacity


3 “20 and Counting”
What are your thoughts?

4 The More the Merrier!!!???

5 Human Population Growth Historically
Early Hunter Gatherers Nomadic, With a Strong Sense of the Earth Practiced Intentional Birth Control Rise of Agriculture Necessary for Survival Animals became extinct via predation and altered habitat Humans began to cultivate own food

6 C. Agriculture Gives Rise to Cities
Food Produced in Country, Consumed in City Food wastes are no longer returned to soil Soil becomes less productive Waste of Populations Concentrated in Cities Population Control in Medieval Societies Infanticide Plagues

7 D. Industrialization View of Children During Early Phases of Industrial Growth Valued as cheap source of income and cheap labor Exponential growth of populations By 1900s, Birth Rate in Industrialized World Dropped Rise in standards of living Safe and inexpensive means of birth control introduced Increase in the cost of child rearing


9 Current World Population
Population Clock Vital Events (per time unit) Global population was 6,669,203,826 On February 27, 2007 at 6:13 am The global population grows by: Nearly 2.3 persons per seconds Nearly 8,343 persons per hour Over 200,234 persons per day Over 73 million persons per year


11 How Much is a Billion? 1,000 seconds = 16.7 minutes
1 million-s = 16,677 min = 11.6 days 1 billion-s = 11,574 days = 31.7 years 1,000 pennies = ~ 88 ounces = 5.5 pounds 1 million pennies = 5,500 pounds (~1-Suburban) 1 billion pennies = 2,750 tons (~2 Space Shuttles)

12 MI L I O NS

13 Factors which Impact Populations
Developing Countries Developed Countries Poorer countries Lower life expectancy High Birth Rates Higher Death Rates Not industrialized Education – males only Unstable governments Higher % of disease Technology is lacking Richer (affluent) countries Higher life expectancy Low Birth Rates Low Death Rates Highly industrialized Better educated citizens Better technology Stable governments Healthcare

14 Population Projections
Over 95% of this increase will take place in “Developing Countries”

15 Countries Comparison Developing Countries Developed Countries
Afghanistan Bangladesh Belize Ethiopia Tonga Tunisia Peru United States Germany Japan Europe Sweden Lichtinstein Ireland Canada



18 Population Pyramids Graphic device: bar graph
shows the age and gender composition of a region horizontal axis: gender male: left-hand female: right-hand absolute number of people or % vertical axis: age 5-year or 10-year age groups

19 Factors affecting pop pyramids
Medicine Disease Technology War Baby Boomers Natural Disasters Women deciding to delay family More attention to health (graying of America) Gay population increasing!! (~1-5%) Immigration / emigration

20 Population Pyramid with young cohorts
Male cohorts Female cohorts

21 Population Pyramids High Growth: Afghanistan
Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: France, Russia Negative Growth: Austria or Italy

22 Bottom Graph: Projected population pyramid for 2025 when one can again see the large cohorts that were born between 1985 and This large number of births is just the “echo effect” of the baby boom bet mid 1960’s and mid-1970’s. Each couple should only have one child according to government policy—so why is the base so large?

23 Top Graph: China’s baby boom that peaked in late 1960’s and early 1970’s. Started in 1950’s-now visible as those generations in 2000 were years of age. Middle Graph: Birth cohorts rapidly declined. Children born bet in 2007 belonged to the smallest birth cohorts after the baby boom. These ind were born bet 1978 & 1985 when family planning took place.


25 Population Pyramids Moderate Growth: Mexico
Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Austria or Italy


27 Population Pyramids Zero Growth: U.S. Population Pyramids on the Web
High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Austria or Italy


29 Population Pyramids Negative Growth: Italy
Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Italy


31 Human Population Dynamics
There are just three sources of change in population size — Fertility (Birth rates) Mortality (Death rates) "natural decrease" refers to population decline resulting from more deaths than births Net migration - is the number of immigrants minus emigrants



34 Rates of Global Pop. Change use: International Data Base http://www
Rates of Global Pop. Change use: International Data Base then Online Demographic Aggregation CBR (crude birth rate) = # births / 1000 population 1990: 24 now: 20.6 CDR (crude death rate) = # deaths / 1000 population 1990: 9 now: 8.8

35 Human Population Dynamics
Total fertility rate (TFR) The average number of children born to a woman Average in developed countries = 1.5 Average in developing countries = 3.8 Worldwide 1990: 3.1 now: 2.76 On each of the country lines, there is a graph representing that country’s fertility rate. As I scroll down the country list, look at the trends of each of the countries and their fertility rates. Identify the trends.


37 Total Fertility Rate

38 Total Fertility Replacement Rate
= The number of children a couple must have to replace themselves (i.e. 2 children) - Also known as replacement-level fertility A TFR of 2.1 for developed countries with low infant and child mortality rates Africa RFR = 2.5 children per couple Mali RFR = 2.7 (ties in with the growth rate—see later) Source:

39 Mali located in Africa

40 Human Population Dynamics
infant mortality rate (IMR) infant deaths per 1000 live births (infant < 1 yr) 1990: 62 now: 52.4 (normal in 1900: 200)

41 http://www. povertymap

42 What Is Family Planning?
Definition Measures enabling parents to control number of children (if they so desire) Goals of Family Planning Not to limit births For couples to have healthy children For couples to be able to care for their children For couples to have the number of children that they want


44 What Methods are Used to Control Births?
Preconception Birth Control Methods Barrier Methods Condom Vaginal sponge Diaphragm Spermicides Hormonal Contraceptives Pill Injections and implants Sterilization Postconception Birth Control Measures Intrauterine Device RU-486 Pill Abortion

45 Contraceptive Use Worldwide
People in industrialized countries enjoy easy access to contraceptives while those in LDCs do not. In the U.S., teens and poor women are least likely to use contraceptives. Severe problems are associated with teen pregnancy.

46 chem-enc-1.html

47 Maternal Deaths per 100,000 Live Births
Source: WHO, UNICEF, UNFPA Maternal Mortality in 1995: Estimates Developed by WHO, UNICEF AND UNFPA, 2001.

48 Growth Rate The average annual rate of change for a population within a specified time period. Noted in a percentage. Growth Rate = (b + i) – (d + e) Total Population (births + immigration) – (deaths + emigration) 1990: 1.5% now: 1.19% growth rates have come down

49 Overall, the world population is growing at a rate of about 1
Overall, the world population is growing at a rate of about 1.7 per cent; if this rate continues, the population will double in 42 years. Unabated, such a rate would lead to a point about 2000 years hence when the mass of humanity would weigh more, and be larger, than the Earth. But, the growth rate is decreasing

50 Rule of 70 Rule of 70 – standard to determine how long it takes for a population to double. Focus on: migration, aging, youth bulge, urbanization and new socio-economic-political consequences. Some countries will double—some will not. World is in j-curve growth.  


52 Rule of 70 Assume that the pop doubles every 70 years.
Problem: If the population has a growth rate of 2%, how long will it take for the population to double? Answer: 70/2 = 35 years to double.

53 Demographic Transition
Movement of a nation from high population growth to low population as it develops economically Transition as a result of four stages Stage 1—Birth and death rates are both high Stage 2—Death rates fall; birth rates remain high; growth rate rises Stage 3—Birth rates fall as standard of living rises; growth rate falls Stage 4—Growth rate continues to fall to zero or to a negative rate

54 The Demographic Transition

55 Five Stages of the Demographic Transition
Used to be 4, now 5 stages birth rates, death rates and growth rates systematically change through time as societies change: modernize, urbanize gain access to technology

56 Population Pyramids and Demographic Stages
characteristics shapes of ‘pyramids’ wide base (true pyramid) wide middle (bulge), somewhat wider base urn- or bottle-shaped reversed pyramid different shapes--different dynamics

57 Stage 1: Pre-Industrial
high birth rates, high (at time erratic) death rates, low growth rates stage for much of human history, traditional societies practically no country today


59 Stage 2 TRANSITIONAL high birth rates, declining death rates,
rising growth rates improvements in sanitation (water) and medicine in Europe during Industrial Revolution in developing countries since the 50s/60s much of Africa today, some countries of Asia (Afghanistan, Nepal, etc.)

60 Population Pyramid and Demographic Transition
Stage 2: wide base stage 3: wide middle stage 4: slender stage 5: narrow base

61 Stage 3 INDUSTRIALIZED continued decline of death
rates, declining birth rates, growth rates decline from high to lower levels change in behavior: adaptation to lower death rate, in particular infant mortality rate economic change: urbanization (incentive to have fewer children) Mexico today

62 Population Pyramid and Demographic Transition
Stage 2: wide base stage 3: wide middle stage 4: slender stage 5: narrow base

63 Stage 4 & 5 POST-INDUSTRIALIZED Stage 4: low birth rates,
low death rates, low growth rates United States today Stage 5: low birth rates, rising death rates, declining growth rates (if birth rates drop below death rates: negative growth rates) several countries of Europe today (Austria)

64 Population Pyramid and Demographic Transition
Stage 2: wide base stage 3: wide middle stage 4: slender stage 5: narrow base

65 Population Pyramid and Demographic Transition
Stage 2: wide base stage 3: wide middle stage 4: slender stage 5: narrow base

66 2010

67 Stage 2 to Stage 4

68 China-Stage 2 to Stage 5?

69 What does this mean to you?

70 China Current Population Trends


72 The Graying of Japan Family-planning access, cramped housing, expensive land, late marriage, education cost --> voluntary decrease in birth rate Low immigration rate Health insurance and pension - 45% of national income; could -->low economy Illegal immigration bolsters work force


74 Influencing Population Size
Most countries restrict immigration Canada, Australia, U.S. - most immigration Involuntary immigration results from armed conflict environmental degradation natural disaster --> environmental refugees ~1% of developing nations pop. Emigrates Migration from rural to urban areas

75 Family Planning: reduce births and abortions
59% contraceptive use in developed countries -46% overall, up from 10% in 60s FP reduces children's social services needs FP reduces risk of childbearing deaths FP effectiveness depends on program design and funding: good in some counties with good program poor in other counties

76 Family Planning: reduce births and abortions -2
Services not always accessible; add female teenagers and sexually active unmarried Add birth control for men (sperm-killing device used in China) If developed countries provided $17 billion/ year, and each person pays $4.80/year, average family size would be 2.1 and world population would be 2.9 billion

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