Population Dynamics

Population Dynamics

Lokhaze AliVisiting Faculty

NICE, SCEE, NUST

Population Dynamics 2


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.


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.


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


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


Population in major areas, estimates and medium scenario:

1950-2300


Estimated World-Population1800-2100


UN DESA continent population 1950 to 2100


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%


Ranking of 15 Most Populous Countries from 1970 to 2050


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


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


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


Arithmetic or Zero Order

dp/dt= Ka

P = P1 + Ka (t - t1)

Ka = (P2-P1)/ (t2-t1)

P = populationt = timeKa = arithmetic growth

constant


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


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


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


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


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


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


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


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


Pakistan’s Population


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


Pakistan Population Policy2010


Our Future-Our Choices

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Population Dynamics

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