WOLFRAM SYSTEMMODELER

Population_Dynamics

Population dynamics

Diagram

Wolfram Language

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SystemModel["SystemDynamics.WorldDynamics.World3.Population_Dynamics"]
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Information

This model describes the population dynamics of the WORLD3 model. Whereas the earlier WORLD2 model had lumped all of the population together into a single state variable, WORLD3 offers a demographic model that distinguishes between four age groups, those of the children, those of the younger adults representing the child-bearing population, those of the older adults who are still in the work force, and finally, those of the retired population.

Population is measured in numbers of living humans. In accordance with engineering practice, which (arbitrarily) assigns measurement units only to real-valued quantities and not to integer-valued quantities, this model lists the population as dimensionless.

This model is described on p.142 of Dynamics of Growth in a Finite World.

Public Parameters (7)

pop1_init

Value: 650000000.0

Type: Real

Description: Initial population 14 years and younger

pop2_init

Value: 700000000.0

Type: Real

Description: Initial population 15 to 44 years old

pop3_init

Value: 190000000.0

Type: Real

Description: Initial population 45 to 64 years old

pop4_init

Value: 60000000.0

Type: Real

Description: Initial population 65 years and older

labor_force_partic

Value: 0.75

Type: Real

Description: Percentage of participating labor force

reproductive_lifetime

Value: 30

Type: Real (yr)

Description: Reproductive life time

t_pop_equil_time

Value: 4000

Type: Real (yr)

Description: Population equilibrium time

Connectors (4)

life_expectancy

Type: MassInPort

Description: Average life expectancy of human population

labor_force

Type: MassOutPort

Description: Total human labor force

total_fertility

Type: MassInPort

Description: Average human fertility

population

Type: MassOutPort

Description: Population

Components (39)

Births

Type: RRate

Description: p.96 of Dynamics of Growth in a Finite World

source

Type: Source

Pop_0_14

Type: Level2b

Matur_14

Type: RRate

Description: p.141 of Dynamics of Growth in a Finite World

Pop_15_44

Type: Level2b

Description: p.57 of Dynamics of Growth in a Finite World

Matur_44

Type: RRate

Description: p.141 of Dynamics of Growth in a Finite World

Pop_45_64

Type: Level2b

Description: p.57 of Dynamics of Growth in a Finite World

Matur_64

Type: RRate

Description: p.141 of Dynamics of Growth in a Finite World

Pop_65plus

Type: Level

Description: p.57 of Dynamics of Growth in a Finite World

Deaths_65p

Type: RRate

Description: p.57 of Dynamics of Growth in a Finite World

sink

Type: Sink

births

Type: Birth_Factors

Description: p.96 of Dynamics of Growth in a Finite World

Deaths_0_14

Type: RRate

Description: p.57 of Dynamics of Growth in a Finite World

sink1

Type: Sink

Deaths_15_44

Type: RRate

Description: p.57 of Dynamics of Growth in a Finite World

sink2

Type: Sink

Deaths_45_64

Type: RRate

Description: p.57 of Dynamics of Growth in a Finite World

sink3

Type: Sink

matur_14

Type: Matur_Factors

Description: p.141 of Dynamics of Growth in a Finite World

matur_44

Type: Matur_Factors

Description: p.141 of Dynamics of Growth in a Finite World

matur_64

Type: Matur_Factors

Description: p.141 of Dynamics of Growth in a Finite World

deaths_0_14

Type: Death_Factors

Description: p.57 of Dynamics of Growth in a Finite World

deaths_15_44

Type: Death_Factors

Description: p.57 of Dynamics of Growth in a Finite World

deaths_45_64

Type: Death_Factors

Description: p.57 of Dynamics of Growth in a Finite World

deaths_65p

Type: Death_Factors

Description: p.57 of Dynamics of Growth in a Finite World

Mort_0_14

Type: Tabular

Description: p.57 of Dynamics of Growth in a Finite World

Mort_15_44

Type: Tabular

Description: p.57 of Dynamics of Growth in a Finite World

Mort_45_64

Type: Tabular

Description: p.57 of Dynamics of Growth in a Finite World

Mort_65p

Type: Tabular

Description: p.57 of Dynamics of Growth in a Finite World

Pop_Young

Type: Add

Pop_Old

Type: Add

Population

Type: Add

Death_Young

Type: Add

Death_Old

Type: Add

Deaths

Type: Add

Work_Pop

Type: Add

Description: p.241 of Dynamics of Growth in a Finite World

Labor_Force

Type: Gain

Description: p.241 of Dynamics of Growth in a Finite World

Birth_Rate

Type: BD_Rates

Description: p.97 of Dynamics of Growth in a Finite World

Death_Rate

Type: BD_Rates

Description: p.140 of Dynamics of Growth in a Finite World

Used in Examples (11)

Scenario_11

SystemDynamics.WorldDynamics.World3

Influencing the future 10 years later

Scenario_10

SystemDynamics.WorldDynamics.World3

Influencing the future 20 years earlier

Scenario_9

SystemDynamics.WorldDynamics.World3

Combining the measures of Scenarios #6 and #8

Scenario_8

SystemDynamics.WorldDynamics.World3

More abundant non-recoverable natural resources, birth control, and stable industrial output

Scenario_7

SystemDynamics.WorldDynamics.World3

More abundant non-recoverable natural resources and birth control

Scenario_6

SystemDynamics.WorldDynamics.World3

More accessible non-recoverable natural resources, pollution control, land yield enhancement, erosion protection, and resource efficiency

Scenario_5

SystemDynamics.WorldDynamics.World3

More accessible non-recoverable natural resources, pollution control, land yield enhancement, and erosion protection

Scenario_4

SystemDynamics.WorldDynamics.World3

More accessible non-recoverable natural resources, pollution control, and land yield enhancement

Scenario_3

SystemDynamics.WorldDynamics.World3

More accessible non-recoverable natural resources and pollution control

Scenario_2

SystemDynamics.WorldDynamics.World3

More abundant non-recoverable natural resources

Scenario_1

SystemDynamics.WorldDynamics.World3

Original WORLD3 model