the human population and its impact
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The Human Population and Its Impact. Chapter 6. Reasons for human population increase:. Movement into new habitats and climate zones Early and modern agriculture methods Control of infectious diseases through -Sanitation systems -Antibiotics -Vaccines. :. Death Rate. - PowerPoint PPT PresentationTRANSCRIPT
Reasons for human population increase:
Movement into new habitats and climate zonesEarly and modern agriculture methodsControl of infectious diseases through
-Sanitation systems-Antibiotics-Vaccines
:
Death Rate
UN World Population Projections by 2050
World population is
growing exponentially at a rate of
1.21%
2.0 children
1.5 children
2.5 children
The prospect of
stabilization in the near future is nil.
We are moving from a J-Curve to an S-curve
What does a 1.21% growth rate mean?
• There were about 83 million people added to the earth in 2010
• Which is about 227,000 people every day• Which is 2 more people every time your
heart beats
Population growth in developing countries is increasing 15 times faster than developed
countries
By 2050, 97% of growth will be in developing countries
Should the optimum sustainable population be based on cultural carrying capacity?
Optimum level that allows people to live in reasonable comfort and freedom and still have
sustainability
How Long Can the Human Population Keep Growing?
• Thomas Malthus and population growth: 1798 (Populations increase exponentially , food supply increases linearly. Wrong!! Actually-food-exponentially due to genetic and technological advances)
• Humans have altered 83% of the earth’s land surface
• Can the human population grow indefinitely?
What is really the problem?
• Overpopulation? This is degrading our planet. (82% of population is in less developed nations)
• Overconsumption? Americans ecological footprints are 4.5X larger than the average Chinese and 9.5 times larger than the average Indian
• Technology? These advances have helped eliminate environmental resistances
• How do we alter nature?
The Human Population Can Grow, Decline, or Remain
Fairly Stable• Population change
– Births: fertility– Deaths: mortality– Migration
• Population change =
(births + immigration) – (deaths + emigration)
• Crude birth rate=# of live births per 1000 people in a population
• Crude death rate=# of deaths per 1000 people in a population
Women Having Fewer Babies but Not Few Enough to Stabilize the
World’s Population
• Fertility rate- # of children born to a woman during her lifetime–Replacement-level fertility
rate- avg. # of kids that a couple must bear to replace themselves.
– 2.1 developed-2.5 in developing Total fertility rate (TFR)- avg. # of kids born to a woman during reproductive years.
TFR in 2010:
1.7 per woman in developed
countries
2.7 per woman in developing
countries
• In 2010, TFR in developing countries dropped from 6.2 to 2.7 and in developed countries, from 2.8 to 1.7
• In China, the TFR dropped from 5.7 to 1.5 (from 1972-2010)
• Children as part of the labor force
• Cost of raising and educating children
Fact: : It costs to raise a child in the US from birth to 18.
• Availability of private and public pension
• Urbanization
• Educational and employment opportunities for women-TFR is low as education
Several Factors Affect Birth Rates and Fertility Rates
$220,000
Several Factors Affect Birth Rates and Fertility Rates
• Average age at marriage (the older they are when they marry, the fewer children they usually have)
• Religious beliefs, traditions and cultural norms
Reducing Births PROS• better than raising death rate
• we already fail to provide basic necessities for one-fifth of the world
• over pop. Is the main reason for environmental degradation and resource over consumption
• technology is the key to economic power, not more people
• freedom to reproduce should only apply if it does not reduce the quality of other peoples lives
CONS*people live longer*some people believe that the world can support
millions more*people are our most valuable resource
• Infant mortality rate
• Average age of a woman at birth of first child
• Availability of legal abortions
• Availability of reliable birth control methods
• Religious beliefs, traditions, and cultural norms
Several Factors Affect Death Rates
Population increase is
due to decline in
crude death rate
Migration Affects an Area’s Population Size
Why migrate???
• Economic improvement
• Religious freedom
• Political freedom
• Wars• Environmental refugees-40
million in 2008, water and food shortage, drought
Several Factors Affect Death Rates
• Life expectancy- globally, increased from 47 to Life expectancy- globally, increased from 47 to 69 years from 1955-2010. by 2050…74 years69 years from 1955-2010. by 2050…74 years
• Japan has longest life expectancy of 83 and US Japan has longest life expectancy of 83 and US is 78 (50is 78 (50thth of all nations) of all nations)
• Infant mortality rate- reflects country’s level of Infant mortality rate- reflects country’s level of nutrition and health carenutrition and health care
• Why are people living longer and fewer infants dying?Why are people living longer and fewer infants dying?– Increased food supply and distributionIncreased food supply and distribution– Better nutritionBetter nutrition– Medical advancesMedical advances– Improved sanitationImproved sanitation
• U.S. infant mortality rate high due to
–Inadequate health care for poor women during pregnancy and their infants
–Drug addiction among pregnant women
–High birth rate among teenagers
Legal Immigration to the U.S. between 1820 and 2003
• Immigration Reform and Control Act of 1986: granted legal status to illegal immigrants if they showed they lived in the country several years.
• 36% of US growth is due to legal/illegal immigration
• Many Americans believe all immigration should be reduced.
• Opposition-• It would diminish the historical role of the US
being a place of opportunity for the poor and oppressed
• Take away cultural diversity• Most immigrants pay taxes, start new
businesses and create jobs• Take menial and low paying jobs• Proponents-• Allow immigrants if they can support
themselves• By lowering immigration, the US could stabilize
its population and reduce its ecological footprint
Populations Made Up Mostly of Young People Can Grow Rapidly
• Age structure categories
–Pre-reproductive ages (0-14)
–Reproductive ages (15-44)
–Post-reproductive ages (45-over)Males vs. females
We Can Use Age-Structure Information to Make Population and Economic Projections
• Baby boomers
• Job market when they retire-job shortage
The Fastest Growing Age Group Is…The Fastest Growing Age Group Is…
SENIORS!SENIORS!• The global populations of seniors is projected to triple by 2050 The global populations of seniors is projected to triple by 2050
in which 1 of every 6 people will be 65 or older.in which 1 of every 6 people will be 65 or older.• This graying of the population is due to declining birth rates This graying of the population is due to declining birth rates
and longer life expectancies due to medical advancementsand longer life expectancies due to medical advancements.
Populations Made Up of Mostly Older People Can
Decline Rapidly
• Slow decline– Manageable
• Rapid decline-Japan, Russia, Germany, Hungary, Greece, Italy– Severe economic problems (less in work force,
fewer children to care for grandparents, more spent on medical care, pension funds, and shortages of health-care workers
Fig. 11.20, p. 249
194541.9 workers
40
30
20
10
0
195016.5
20751.9
1945 2000 2050 2075
Nu
mb
er o
f w
ork
ers
sup
po
rtin
gea
ch S
oci
al S
ecu
rity
ben
efic
iary
27 million killed by 2009
Many young adults die: loss of most productive workers
Sharp drop in life expectancy
International community called upon to– Reduce the spread of HIV through
education and health care– Financial assistance and volunteers to
provide education, healthcare, teachers, social workers
Populations Can Decline from a Rising Death Rate: The AIDS
Tragedy
Slowing the Human Population Growth
• Demographic Transition: As countries become industrialized
–Death rate declines
–Then birth rate declines
–4 majors stages…
• US is in the early phase of stage 4 • Most of the less developed countries will make
a demographic transition over the next few decades due to technology and family planning
• Some fear these countries will stay in stage 2 due to extreme poverty, and rapid population growth. Many lack basic services such as food, health care and education. Countries are in civil war, and are training grounds for terrorist groups
• Somalia- 3% population growth, TFR=6.5 and 45% of population under 15.
• Haiti- foreign debt, lack of skilled workers, large number of people in poverty, and the 7.0 earthquake in Jan 2010
Planning for Babies Works
• Family Planning– Responsible for a 55% drop in TFRs– In developing countries– Expansion of program
• Include teenagers, sexually active unmarried women, and men
• Slow and stabilize population growth– Invest in family planning– Reduce poverty– Elevate the social and economic status
of women
• Bangladesh- TFR dropped from 6.0 in 1960 to 2.7 in 2010.
• Family planning and economic development are responsible for the drop.
• Thailand’s TFR dropped from 6.4 to 1.8
• The best way to slow and stabilize population growth are through
1. promoting economic development
2. elevating the social and economic status of women
3. Encouraging family planning
Empowering Women Can Slow Population
Growth• Education-fewer children
• Paying jobs
• Human rights without suppression
• “For poor women the only holiday is when you are asleep”
Women account for 2/3 of all
hours worked, but only get 10%
of world's income
Fig. 11.28, p. 256
4:45 A.M.Wake,wash, andeat
5:00 A.M.-5:30 A.M.Walk tofields
3:00 P.M.-4:00 P.M.Collectfirewood
4:00 P.M.-5:30 P.M.Pound andgrind corn
5:30 P.M.-3:00 P.M.Work infields
5:30 P.M.-6:30 P.M.Collectwater
6:30 P.M.-8:30 P.M.Cook forfamily andeat
8:30 P.M.-9:30 P.M.Washdishesand children
9:30 P.M.Go to bed
Women• Make up 70% of the world’s poor• 64% are illiterate (and 5-7 children)• 60-80% of work associated with
growing food, gathering wood and hauling wood and water
• In most societies, they have fewer rights and educational and economic opportunities
• (Sharbat Gula 1985 and 2002)• (Afghanistan refugee who crossed
over into Pakistan)
Slowing growth in India• 1952- the first national family planning
program began• 2nd largest population today, but projected
to be the largest by 2015• 32% of its population is under 15• 4th largest economy, growing middle class• Faces poverty, malnutrition and
environmental problems• ¼ of urban population lives in slums• 2/3 of population lives in rural areas• Nearly ½ are unemployed or
underemployed• ¾ live on less than $2.25 a day
• Most poor couples believe they need several children to work and care for them in old age
• Cultural preference for male children• Only 48% use some form of birth control• 17% of world’s population, 2.3% of land
and 2% of forests• Soil erosion and overgrazing of ½ of
croplands• 2/3 water is polluted• Sanitation often inadequate• Economic growth= larger ecologic
footprint but possible a slower population growth
Population Calculations
Global population
growth rate = CBR-CDRCBR-CDR
1010
If there were 20 people born per 1,000 people and 8 deaths per 1,000, the global population growth rate would be 1.2% 20-8
10
In 2011, the population growth rate of the ….
world was 1.09%
Zimbabwe = 4.3%
Japan = -0.1%
US = 0.9%
China= 0.5%
India = 1.3%
• To calculate the population growth rate for a single nation, we take immigration and emigration into account.
• Nat. pop = (CBR + immigr) – (CDR+ emigr)
growth rate 10
Fig. 11.3, p. 240
<1%
1-1.9%
2-2.9%
3+%
Data notavailable
Annual worldpopulation growth
Population Growth Rate
• If we know the growth rate of a population and assume that growth rate is constant, we can calculate the number of years it takes for a population to double. Doubling Time
• Rule-of-70 - way to calculate the approximate number of years it takes for the level of a population growing at a constant rate to double.
• States that the approximate number of years n for a variable growing at the constant growth rate of r percent, to double is:
n = 70/r
For example, a city with an annual population growth rate of 5% will double its population in approximately 14 years. 70 =14
5 If the growth rate were 7%, it would double its population in approximately ? years.
10
• Remember that a population growing at 2 percent per year, regardless of the size
will double in 35 years. Whether the population is 500,000 or 50,000, it will still
double in the same amount of time.
• It is almost certain that the Earth’s population will not double again. Most demographers believe that the human
population will be somewhere between 8.1 billion and 9.6 billion in 2050 and stabilize
by 2100.
• New Zealand has a population of 4.3 million people, a TFR of 2.1 and a net migration rate of 2 per 1,000. How many people will New Zealand gain next year as a result of immigration? (assume the TFR and net migrations stays the same)
• Net migration = # of immigrants
rate # of people in pop
A TFR of 2.1 for a developed country suggests that the country is at replacement-level fertility and thus the population is stable.
• The migration rate suggest that• 2__ = __ x_ _
1000 4,300,000
So, X= 8,600 people/year
Since there is no growth due to biological replacement and a net migration of 8,600 people, the rate of increase is
8,600 people/year = 0.2%
4,300,000 people
How many years will it take the population to double at this rate?
• A metropolitan region of 100,000 people has 2,000 births, 500 deaths, 200 emigrants, and 100 immigrants over a 1 year period. Calculate its population growth rate.
• Net increase = 2,100• Net decrease= 700
• Total change in population= 1400• Total number in population = 100,000• = 0.014 = 1.4%
• In 2010, the population of Upper Fremont was 200,000 and growing at a rate of 2% each year.
• If the rate of population growth remains constant, calculate the population in 2045.
• Determine the doubling time of the population by dividing 70 by 2 to get 35 years. Since one 35-year period passes between 2010 and 2045, the population would have doubled once from 200,000 to 400,000.
• The population of Lower Fremont was 20,000 in 1968. In 2010 the population was 160,000. Assuming the growth is exponential, calculate the average annual percentage rate of population growth since 1968.
• 2010-1968 = 42 years• The population has doubled 3 times
since 1968. 20,000 → 40,000 → 80,000 → 160,000
• 42/3 = 14 years• T= 70/r and r= 70/t• 70/14 = 5%
• In 2010, the CBRin East Fremont was 25 and the CDR was 11. Calculate the percentage growth rate of East Fremont in 2010. If the population was 15,000 in 2010, and the population growth rate remains constant, when will the population reach 30,000?
__CBR-CDR__ 14 = 1.4%
10 10
70/1.4 = 50 years
50 years + 2010 = 2060
Population Density
• New York City has 8,175,113 people within 305 mi2.
• Calculate the density of the population in mi2 and km2. 1 km2 = 0.386 mi2
• 8,175,113 people = 26,804 people/ mi2
305 mi2
26,804 people x 0.386 mi2 = 10,346 people
1 mi2 1 km2 km2
The population of Atlanta is 420,003 and covers an area of 131 square miles.Calculate the density of the population inin mi2 and km2
420,003 people = 3206 people/ mi2
131 mi2
3206 people x 0.386 mi2
mi2 1 km
= 1238 people/km2
• The tiny country of Monaco has the world's highest population density. With an area of 3/4 of a square mile and a total population of 32,000, Monaco has a density of almost 43,000 people per square mile.
• However, since Monaco and other microstates have very high densities due to their extremely small size, Bangladesh is often considered the most densely populated country, with more than 2,200 people per square mile.
States by density: New Jersey, Rhode Island, Massachusetts- density
States: California, Texas, New York by population
Cities: New York, LA, Chicago by population
““People are People are everywhere. everywhere. Some people Some people say there are say there are too many of too many of
us, but no one us, but no one wants to wants to leave.”leave.”
The End
If the world had 100 people…
• http://www.100people.org/statistics_detailed_statistics.php?section=statistics
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