WOLFRAM SYSTEM MODELER

Scenario_6

6th Scenario

Diagram

Wolfram Language

In[1]:=
SystemModel["SystemDynamics.WorldDynamics.World2.Scenario_6"]
Out[1]:=

Information

The 6th scenario starts out from the 2nd scenario. We now wish to vary the resource utilization rate after the year 1970.


References:

  1. Cellier, F.E. (1991), Continuous System Modeling, Springer-Verlag, New York, ISBN: 0-387-97502-0, 755p.
  2. Forrester, J.W. (1971), World Dynamics, Pegasus Communications, 160p.


Simulate the model six times across 200 years while keeping all six trajectories (plot setup menu). For the six simulation runs, choose different levels of resource utilization after the year 1970:
NRUN2 = {0.25, 0.5, 0.75, 1.0, 1.25, 1.5}.

Compute a performance index:
Perf_Index = min_QL + 5*min_dPop;
where min_QL is the minimal quality of life observed between 2000 and 2100, and min_dPop is the largest negative population gradient observed in the same time period.

Plot the performance index across the calendar years between 2000 and 2100 for all six scenarios on a single graph:

NRUN2 = 0.25 and NRUN2 = 0.5 lead to massive die-off, whereas the other scenarios avoid this problem. However in the short run, those scenarios that offer the worst long-term performance are characterized by the best short-term performance. This is the predicament that humanity is currently facing.


Parameters (21)

Population_0

Value: 1650000000.0

Type: Real

Description: World population in 1900

Pollution_0

Value: 200000000.0

Type: Real

Description: Pollution in 1900

Nat_Resources_0

Value: 900000000000.0

Type: Real (ton)

Description: Unrecoverable natural resources in 1900

Cap_Invest_0

Value: 400000000.0

Type: Real (dollar)

Description: Capital investment in 1900

CIAF_0

Value: 0.2

Type: Real

Description: Proportion of capital investment in agriculture in 1900

BRN

Value: 0.04

Type: Real (1/yr)

Description: Normal birth rate

CIAFN

Value: 0.3

Type: Real (dollar)

Description: CIAF normalization

CIAFT

Value: 15.0

Type: Real (yr)

Description: CIAF time constant

CIDN

Value: 0.025

Type: Real (dollar/yr)

Description: Normal capital discard

CIGN

Value: 0.05

Type: Real (dollar/yr)

Description: Normal capital generation

DRN

Value: 0.028

Type: Real (1/yr)

Description: Normal death rate

ECIRN

Value: 1.0

Type: Real (dollar)

Description: Capital normalization

FC

Value: 1.0

Type: Real (kg/yr)

Description: Food coefficient

FN

Value: 1.0

Type: Real (kg/yr)

Description: Food normalization

Land_Area

Value: 135000000.0

Type: Real (hectare)

Description: Area of arable land

NRI

Value: 900000000000.0

Type: Real (ton)

Description: Initial natural resources

POLN

Value: 1.0

Type: Real (1/yr)

Description: Normal pollution

POLS

Value: 3599900000.0

Type: Real

Description: Standard pollution

Pop_dens_norm

Value: 26.5

Type: Real (1/hectare)

Description: Normal population density

QLS

Value: 1.0

Type: Real

Description: Standard quality of life

NRUN2

Value: 1.0

Type: Real (1/yr)

Description: Resource utilization after 1970

Outputs (6)

Pop

Type: Real

Description: World population

Pol

Type: Real

Description: Pollution

Pol_rat

Type: Real

Description: Pollution ratio

Cap_inv

Type: Real (dollar)

Description: Capital investment

Qual_life

Type: Real

Description: Quality of life

Nat_res

Type: Real (ton)

Description: Natural unrecoverable resources

Components (78)

Source1

Type: Source

Description: This is the (dummy) source model of System Dynamics

Birth_Rate

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

Population

Type: Level

Description: General System Dynamics level

Death_Rate

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

Sink1

Type: Sink

Description: This is the (dummy) sink model of System Dynamics

Source2

Type: Source

Description: This is the (dummy) source model of System Dynamics

Generation

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

Natural_Resources

Type: Level

Description: General System Dynamics level

Depletion

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

Sink2

Type: Sink

Description: This is the (dummy) sink model of System Dynamics

Gen_Const

Type: Const

Description: A constant factor

BRMM

Type: Tabular

Description: Tabular function

DRMM

Type: Tabular

Description: Tabular function

BR_norm

Type: Gain

Description: Gain factor

Prod_5_1

Type: Prod_5

Description: Product of five influencing factors

DR_norm

Type: Gain

Description: Gain factor

Prod_5_2

Type: Prod_5

Description: Product of five influencing factors

BRFM

Type: Tabular

Description: Tabular function

BRPM

Type: Tabular

Description: Tabular function

BRCM

Type: Tabular

Description: Tabular function

DRCM

Type: Tabular

Description: Tabular function

DRPM

Type: Tabular

Description: Tabular function

DRFM

Type: Tabular

Description: Tabular function

Crowd_Rat

Type: Gain

Description: Gain factor

Prod_2_1

Type: Prod_2

Description: Product of two influencing factors

NRMM

Type: Tabular

Description: Tabular function

Source3

Type: Source

Description: This is the (dummy) source model of System Dynamics

CI_Generation

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

Capital_Investment

Type: Level

Description: General System Dynamics level

CI_Discard

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

Sink3

Type: Sink

Description: This is the (dummy) sink model of System Dynamics

CIG_norm

Type: Gain

Description: Gain factor

Prod_2_2

Type: Prod_2

Description: Product of two influencing factors

CID_norm

Type: Gain

Description: Gain factor

CIM

Type: Tabular

Description: Tabular function

MSL

Type: Gain

Description: Gain factor

NRFR

Type: Gain

Description: Gain factor

ECIR

Type: Gain

Description: Gain factor

Prod_3_1

Type: Prod_3

Description: Product of three influencing factors

NREM

Type: Tabular

Description: Tabular function

CIR

Type: Division

Description: Output first input divided by second input

Source4

Type: Source

Description: This is the (dummy) source model of System Dynamics

P_Generation

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

Pollution

Type: Level

Description: General System Dynamics level

P_Absorption

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

Sink4

Type: Sink

Description: This is the (dummy) sink model of System Dynamics

NotCIAF

Type: Linear

Description: Linear function

Pol_Ratio

Type: Gain

Description: Gain factor

FCM

Type: Tabular

Description: Tabular function

Prod_3_2

Type: Prod_3

Description: Product of three influencing factors

Food_Ratio

Type: Gain

Description: Gain factor

Source5

Type: Source

Description: This is the (dummy) source model of System Dynamics

CIAFG

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

CIAF

Type: Level

Description: General System Dynamics level

CIAFD

Type: Rate_1

Description: Unrestricted rate element with one influencing variable

Sink5

Type: Sink

Description: This is the (dummy) sink model of System Dynamics

CIAF_D

Type: Gain

Description: Gain factor

CIAF_G

Type: Gain

Description: Gain factor

Prod_2_3

Type: Prod_2

Description: Product of two influencing factors

P_Abs

Type: Division

Description: Output first input divided by second input

Pol_norm

Type: Gain

Description: Gain factor

Prod_2_4

Type: Prod_2

Description: Product of two influencing factors

POLCM

Type: Tabular

Description: Tabular function

POLAT

Type: Tabular

Description: Tabular function

CFIFR

Type: Tabular

Description: Tabular function

FPM

Type: Tabular

Description: Tabular function

Prod_2_5

Type: Prod_2

Description: Product of two influencing factors

CIRA

Type: Gain

Description: Gain factor

FPCI

Type: Tabular

Description: Tabular function

CIQR

Type: Tabular

Description: Tabular function

QLMF

Type: Division

Description: Output first input divided by second input

QLM

Type: Tabular

Description: Tabular function

QLF

Type: Tabular

Description: Tabular function

Prod_4_1

Type: Prod_4

Description: Product of four influencing factors

QLC

Type: Tabular

Description: Tabular function

QLP

Type: Tabular

Description: Tabular function

Quality_of_Life

Type: Gain

Description: Gain factor

NR_norm

Type: Parameter_Change

Description: Parameter variation of WORLD2 model