Post on 18-May-2015
Population Dynamics
Lokhaze AliVisiting Faculty
NICE, SCEE, NUST
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Population Dynamics 3
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Septimius Tertullianus, 200 B.C
• One thing is sure - the earth is now more cultivated and developed than ever before. There is more farming with pure force, swamps are drying up, and cities are springing up on unprecedented scale
• We've become a burden to our planet. Resources are becoming scare, and soon nature will no longer be able to satisfy our needs. The time will ultimately come when pest, hunger, floods and war will diminish the excessive numbers of our human species.
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Global population evolution The history of the global population
For thousands of years the world population remained well below 500 million. Within the last 200 years the population grew at an enormous speed to over 7 billion.
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World Population: Time to Add Successive Billions in World Population, 1800 to 2050
Source: United Nations 1995; United Nations World Population Prospects: The 2008 Revision Population Database
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What is Population?
Number of people residing in a country and is measured as a snapshot at a particular time
The two components of Population Growth• Natural Increase• Net overseas migration
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Population in major areas, estimates and medium scenario:
1950-2300
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Estimated World-Population1800-2100
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UN DESA continent population 1950 to 2100
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Top 10 World Most Populous Countries
Rank Country / Territory Population Date % of worldpopulation
1 China 1,356,110,000 February 22, 2013 19.2%
2 India 1,210,193,422 March 2011 17%
3 United States 315,550,000 February 22, 2013 4.46%
4 Indonesia 237,641,000 May 2010 3.36%
5 Brazil 197,755,000 February 22, 2013 2.8%
6 Pakistan 182,310,000 February 22, 2013 2.58%
7 Nigeria 170,123,740 July 2012 2.41%
8 Bangladesh 161,083,804 July 2012 2.28%
9 Russia 141,927,297 January 1, 2010 2.008%
10 Japan 127,547,000 June 1, 2012 1.8%
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Ranking of 15 Most Populous Countries from 1970 to 2050
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If the World were 100 PEOPLE
• 50 would be female50 would be male
• 26 would be childrenThere would be 74 adults, 8 of whom would be 65 and older
• 60 Asians15 Africans14 Americans11 Europeans
• 33 Christians22 Muslims14 Hindus7 Buddhists12 people who practice other religions12 people who would not be aligned with a religion
• 83 would be able to read and write; 17 would not
• 7 would have a college degree22 would own or share a computer
• 77 people would have a place to shelter them from the wind and the rain, but 23 would not
• 87 would have access to safe drinking water13 people would have no clean, safe water to drink
Population Forecasts
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Population Forecasts
• Population forecasts depend on the amount and type of data available
• Population forecasts also depend on the resources available i.e. the amount of money that you are willing to spend
• Forecasts are susceptible to error if for no other reason that nobody knows the future
Methods • Graphical• Mathematical or
Logistical• Ratio and
Correlation• Component• Population
Densities
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Graphical
• First step in any projection exercise should be to graph the data
• Graphical projections of past population growths are used to estimate future population growth
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 20050
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
Population vs Time
Years
Po
pu
lati
on
Interpolated values lie between known points
Extrapolated values lie beyond know points
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Arithmetic or Zero Order
dp/dt= Ka
P = P1 + Ka (t - t1)
Ka = (P2-P1)/ (t2-t1)
P = populationt = timeKa = arithmetic growth
constant
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Example # 1Given: Arithmetic Numerical Caset1 = 1990, P1=110,500
t2 = 2000, P2=118,200
Find: A.) Ka
B.) General equationC.) Population in 2020 A.) Ka
Ka = (P2-P1)/ (t2-t1)
= (118200-110500)/(2000-1990) = 7700/10Ka = 770
B.) General equationP = P1 + Ka (t - t1)
P = 110,500 + 770 (t - t1990), based on 1990Any population and the corresponding year may be used:P = 118,200 + 770 (t - t2000), based on 2000
C.) Population in 2020P2020 =P1990 + Ka (t2020 - t1990)
P2020 = 110,500 + 770 (2020-1990), based on 1990P2020 = 110,500 + 23,100
P2020 = 133,600
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Geometric or First Order
dp/dt= KgP
lnP = lnP1 + Kg (t - t1)
Kg = (lnP2-lnP1)/(t2-t1)
Kg = ln(P2/P1)/(t2-t1)
P = populationt = timeKg = geometric growth constant
Note: lim (1+K)1/K = e = 2.718… base of the natural logarithms
K0
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Example # 2
Given: Geometric Numerical Caset1 = 1990, P1=110,500
t2 = 2000, P2=118,200
Find: A.) Kg
B.) General equationC.) Population in 2020 A.) Kg
Kg = ln(P2)-ln(P1)/(t2-t1)
= ln(P2/P1)/(t2-t1)
=(ln1182000-ln110500)/(2000-1990) = 0.07/10Kg = 0.00700
B.) General equationlnP = lnP1 + Kg (t - t1)
lnP = ln (110,500) + 0.00700(t-1990)lnP = 11.61+0.00700(t-1990)P = e(11.61+.00700(t-1990)
Any population and the corresponding year may be used: C.) Population in 2020lnP2020 =lnP1990 + Ka (t2020 - t1990)
lnP = 11.61 + 0.00700(2020-1990) = 11.61 + 0.21lnP = 11.82P2020 = e 11.82
P2020 = 135,944
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Ratio and Correlation Method
• Assumes that the population growth rate of any given community can be related to a larger region, i.e. county, state.
• Use of the appropriate scale factor allows correlation
Formulas P2/P2R = P1/P1R = KR
P2 = Projected population
P2R = Projected population in the larger regionP1 = Population at last census for the projected regionP1R = Population at last census for the projected region in the larger regionKR = ratio or correlation constant
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Component Method
Based on the detailed analysis of the components that make up population growth:• Natural increase,
births over deaths• Migration whose
accurate determination is extremely complex
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Population Densities• Zoning Categories (Typical, vary
by community)• "Fly", survey the town to gather
topographical, physical data.• Consult the community
planning entity and determine the zoning plan.
• Combine the zoning and physical data.
• Measure the number of acres in each zoning category. Multiply the acreage by the density. Total the results which is the current population if existing acreage is used or the saturation population if all the land is considered.
Zoning Category Density (persons/acre)
Residential - single 5-35
Residential - multiple 30-100
Apartments 100-1000
Commercial 15-30
Industrial 5-15
Open 0
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Example # 3
Zoning Category Area(acres)Residential - single 457Residential - multiple
112
Apartments 3Commercial 87Industrial 22Open 176
Zoning Category
Area (acres) Usage(people/acre)
Pop
Residential - single
457 20 9,140
Residential - multiple
112 65 7,280
Apartments 3 550 1,650Commercial 87 22.5 1,958Industrial 22 10 220
Open 176 0 0TOTAL 20,248
Given: You have overflown a city, identified the zoning compositions and plain metered the areas with the following result:
Find: The population
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Assignment # 2 Due Date: 4th March,2013
Given: Arithmetic Numerical Caset1 = 2000, P1=150,000
t2 = 2010, P2=178,200
Find: A.) Ka
B.) General equationC.) Population in 2020, 2030 and 2050
Note: The assignment should be handwritten and submitted individually
Given: Geometric Numerical Caset1 = 2000, P1=150,000
t2 = 2010, P2=178,200
Find: A.) Kg
B.) General equationC.) Population in 2020, 2030 and 2050
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Pakistan’s Population
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Pakistan’s Population RankOrder in the World
Year Rank Population (Million)1950 14 33.02009 6 169
Net Addition in PopulationBIRTHS DEATHS ADDITION
In One Year 4.2M 1.3M 2.9M
One Month 350,833 110,000 240,833
One Day 11,534 3,616 7,918
One Minute 8 3 5
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Pakistan Population Policy2010
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Our Future-Our Choices