december 2011. human population growth: historical perspective the human population has experienced...
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December 2011
Human Population Growth: Historical PerspectiveThe human population has experienced exponential
growth over the past 200 years. Why?
Expanded into diverse habitats and climate zones.Development of modern agricultureModern sanitation and public health advancesDevelopment of antibiotics and vaccinationsHarnessed concentrated sources of energy
The Bottom LineNo population can continue to grow indefinitely.Degradation of natural systems and resources jeopardizes our ability to
sustain populations and build economies.Differential effect of developed vs. developing countries
In 2006, developed countries added 1.2 million people Developing countries added 79.5 million people.
Population Growth Projections
By 2050, human population is projected to be between 7.2 and 10.6 billion people.
97% of the growth in developing countries.
Factors Affecting Human Population Size
When births plus immigration exceed deaths plus emigration, population increases; when the reverse is true, population declines.
This is true of other species as well as humans.
Comparison of birth rates and death rates
Demographers use:
Birth rate or crude birth rate: number of live births per 1,000 people in a population in a given year (U.S. – 14.18)
Death rate or crude death rate: number of deaths per 1,000 people in a population in a given year (U.S. – 8.27)
Declining Population: Observing Fertility Rates
Fertility – number of children born to a woman during her lifetime.replacement –level fertility - number of children a couple
must bear to replace themselves Typically between 2.1 and 2.5 children per couple
Total fertility (TFR) – average number of children a woman typically has during her reproductive years Global average about 2.7 Developed countries about 1.6
United States – 2.06 Developing countries about 2.9 Range according to CIA (0.91 in Macau and 7.68 in Niger)
Population Projections
Case Study: Fertility and Birth Rates in the U.S.
1900 – 76 million AmericansBaby boom – post WWII – 1946 to 1964
Birth rate up to 3.7 at one pointCorresponding “baby bust” – 1964 to 1977
Due to delayed marriage, contraceptive use, and abortion2007 – saw 300 millionth American
56% growth due to birth rate, 44% due to immigrationImmigration shift from Europe to Latin American/Southeast
AsiaHigh per capita resource use
Case Study: Fertility and Birth Rates in the U.S.
Case Study: Fertility and Birth Rates in the U.S.
Think about how life has changed…
Case Study: Fertility and Birth Rates in the U.S.
In the United States in 1905… Three leading causes of death: pneumonia,
tuberculosis, and diarrhea 90% of doctors had no college education 1 out 5 adults cannot read or write Average U.S. worker earns $200-$400 per
year Only 9,000 cars in the U.S. with 144 miles of
paved roads 3 minute phone call cost $11 30 people live in Las Vegas, NV Most women washed their hair once a
month
In the United States NOW… Three leading causes of death: heart
disease, cancer, stroke Common path to becoming a physician
requires 8 years of college and 3-8 years of internship and residency
99% literate Average U.S. worker earns $42,028 per
year (2005 figures according to Worldsalaries.com)
450 million cars in the U.S. with 5.7 million miles of paved roads
3 minute phone call costs $0.51 (according to Mr. Bromwell’s cell phone plan)
567,641people live in Las Vegas, NV I would imagine hair washing is daily
among other things…
Tractor-plow, 1905
Factors Affecting Birth Rates and Fertility RatesImportance of children as part of the labor forceCost of raising and educating childrenAvailability of private and public pension systemsUrbanizationEducational and employment opportunities available for
womenInfant mortality rateAverage age at marriage (or first child)Availability of legal abortionsAvailability of reliable birth control methodsReligious beliefs, traditions and cultural norms
Factors Affecting Death RatesAvailability of food suppliesNutrition quality of available food suppliesAvailability of medical care, immunization, and
antibioticsSanitationSafe drinking water suppliesCivil, governmental, or societal unrest or disadvantageInfant mortality rate
Life Expectancy and Infant Mortality RateTwo useful indicators of overall health of a population:Life expectancy – average number of years a newborn
infant can expect to liveInfant mortality rate – number of babies out of every
1,000 born who die before their first birthdaySingle best measure of a society’s qualityReflects overall nutrition and health care
Infant Mortality in the U.S.
In U.S. approximately 6.3 deaths / 1,000 births
Higher than expected due to inadequate health care for poor women during pregnancy,
drug addiction among pregnant women,
and a high birth rate among teenagers.
Migration Immigration + emigrationSince 1820, U.S. admitted twice as
many immigrants as all other nations combined!
Legal vs. illegal immigrationRacial/ethnic shift Pros
‘land of opportunity’ Accept undesirable jobs, pay taxes,
create jobs Will replace aging boomer
generationCons
Increase countries population, strain resources
Magnet for world’s poor
Population Age StructureThe distribution of males and
females in each age group in the world’s population
Age structure diagrams Examine # of people in three age
categoriesprereproductivereproductivepostreproductive
Population Age Structure Diagrams
The Baby-BoomersThis generation makes up half of all adult workers and
dominates demand for goods and services.
Consequences of Population Decline• Can threaten economic growth • Less government revenues with fewer
workers• Reduces availability of young people for
military service• Less entrepreneurship and new
business formation• Less likelihood for new technology
development• Increasing public deficits to fund higher
pension and healthcare costs
Global Aging
The Demographic Transition
Fig. 9-15, p. 186
Total fertility rate
Percentageof world
populationPopulation
Population (2050)(estimated)
Illiteracy (% of adults)
Population under age 15 (%)
Population growth rate (%)
17%20%
1.1 billion1.3 billion
1.6 billion
IndiaChina
GDP PPP per capita
Percentage livingbelow $2 per day
Life expectancy
47%17%
36%20%
1.6%0.6%
1.4 billion
$5,890$3,120
4780
70 years62 years
2758
1.6 children per women (down from 5.7 in 1972)
Infant mortality rate
2.9 children per women (down from 5.3 in 1970)
ReferencesAnnual Estimates of the Resident Population for Incorporated Places in Nevada: April 1, 2000 to July 1, 2009" (CSV). United States
Census Bureau, Population Division. 2010-09. http://www.census.gov/popest/cities/tables/SUB-EST2009-04-32.csv. Retrieved 2010-11-16
“Infant Mortality Rate (per 1,000 live births)” Digital Image. Unnatural Causes. 2008. California Newsreel. 11 January, 2009. http://www.unnaturalcauses.org/interactivities_04-6.php
Miller, G.T. Living in the Environment: 15th edition. Brooks/Cole, Belmont, CA, 2007.“Population by region” Digital Image. The Sustainable Scale Project. 2003. The Santa-Barbara Family Foundation. 11 January,
2009. http://www.sustainablescale.org/AreasofConcern/Population/PopulationandScale/QuickFacts.aspx“Population growth” Digital Image. The Sustainable Scale Project. 2003. The Santa-Barbara Family Foundation. 11 January, 2009.
http://www.sustainablescale.org/AreasofConcern/Population/PopulationandScale/QuickFacts.aspx"Rank Order - Total Fertility Rate." CIA - The World Fact Book. 18 Dec 2008. Central Intelligence Agency. 11 Jan 2009
<https://www.cia.gov/library/publications/the-world-factbook/rankorder/2127rank.html>.