WOLFRAM SYSTEM MODELER

6th Scenario

# 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 Value: 200000000.0 Type: Real Description: Pollution in 1900 Value: 900000000000.0 Type: Real (ton) Description: Unrecoverable natural resources in 1900 Value: 400000000.0 Type: Real (dollar) Description: Capital investment in 1900 Value: 0.2 Type: Real Description: Proportion of capital investment in agriculture in 1900 Value: 0.04 Type: Real (1/yr) Description: Normal birth rate Value: 0.3 Type: Real (dollar) Description: CIAF normalization Value: 15.0 Type: Real (yr) Description: CIAF time constant Value: 0.025 Type: Real (dollar/yr) Description: Normal capital discard Value: 0.05 Type: Real (dollar/yr) Description: Normal capital generation Value: 0.028 Type: Real (1/yr) Description: Normal death rate Value: 1.0 Type: Real (dollar) Description: Capital normalization Value: 1.0 Type: Real (kg/yr) Description: Food coefficient Value: 1.0 Type: Real (kg/yr) Description: Food normalization Value: 135000000.0 Type: Real (hectare) Description: Area of arable land Value: 900000000000.0 Type: Real (ton) Description: Initial natural resources Value: 1.0 Type: Real (1/yr) Description: Normal pollution Value: 3599900000.0 Type: Real Description: Standard pollution Value: 26.5 Type: Real (1/hectare) Description: Normal population density Value: 1.0 Type: Real Description: Standard quality of life Value: 1.0 Type: Real (1/yr) Description: Resource utilization after 1970

# Outputs (6)

Pop Type: Real Description: World population Type: Real Description: Pollution Type: Real Description: Pollution ratio Type: Real (dollar) Description: Capital investment Type: Real Description: Quality of life Type: Real (ton) Description: Natural unrecoverable resources

# Components (78)

Source1 Type: Source Description: This is the (dummy) source model of System Dynamics Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Level Description: General System Dynamics level Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Sink Description: This is the (dummy) sink model of System Dynamics Type: Source Description: This is the (dummy) source model of System Dynamics Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Level Description: General System Dynamics level Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Sink Description: This is the (dummy) sink model of System Dynamics Type: Const Description: A constant factor Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Gain Description: Gain factor Type: Prod_5 Description: Product of five influencing factors Type: Gain Description: Gain factor Type: Prod_5 Description: Product of five influencing factors Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Gain Description: Gain factor Type: Prod_2 Description: Product of two influencing factors Type: Tabular Description: Tabular function Type: Source Description: This is the (dummy) source model of System Dynamics Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Level Description: General System Dynamics level Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Sink Description: This is the (dummy) sink model of System Dynamics Type: Gain Description: Gain factor Type: Prod_2 Description: Product of two influencing factors Type: Gain Description: Gain factor Type: Tabular Description: Tabular function Type: Gain Description: Gain factor Type: Gain Description: Gain factor Type: Gain Description: Gain factor Type: Prod_3 Description: Product of three influencing factors Type: Tabular Description: Tabular function Type: Division Description: Output first input divided by second input Type: Source Description: This is the (dummy) source model of System Dynamics Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Level Description: General System Dynamics level Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Sink Description: This is the (dummy) sink model of System Dynamics Type: Linear Description: Linear function Type: Gain Description: Gain factor Type: Tabular Description: Tabular function Type: Prod_3 Description: Product of three influencing factors Type: Gain Description: Gain factor Type: Source Description: This is the (dummy) source model of System Dynamics Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Level Description: General System Dynamics level Type: Rate_1 Description: Unrestricted rate element with one influencing variable Type: Sink Description: This is the (dummy) sink model of System Dynamics Type: Gain Description: Gain factor Type: Gain Description: Gain factor Type: Prod_2 Description: Product of two influencing factors Type: Division Description: Output first input divided by second input Type: Gain Description: Gain factor Type: Prod_2 Description: Product of two influencing factors Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Prod_2 Description: Product of two influencing factors Type: Gain Description: Gain factor Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Division Description: Output first input divided by second input Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Prod_4 Description: Product of four influencing factors Type: Tabular Description: Tabular function Type: Tabular Description: Tabular function Type: Gain Description: Gain factor Type: Parameter_Change Description: Parameter variation of WORLD2 model