Source code documentation

Contents

WorldDynamics constants

WorldDynamics functions

Functions in functions.jl

This functions correspond to DYNAMO functions used in the World3 model.

WorldDynamics.clipMethod

clip(returnifgte, returniflt, inputvalue, threshold)

Returns returnifgte if the value inputvalue is greater than the threshold threshold, returniflt otherwise. This function corresponds to the CLIP (also called FIFGE) function in the DYNAMO language.

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WorldDynamics.interpolateMethod

interpolate(x, yvalues, xrange)

Returns the value of a function with input x, by linearly interpolating the function itself through the table yvalues and the range xrange. If x is out of the range, the value at the corresponding extremity is returned. This function corresponds to the TABHL function in the DYNAMO language. This latter function receives a table (that is, yvalues), a value (that is, x), a left and a right extreme of an interval (that is, xrange), and an increment value.

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WorldDynamics.stepMethod

step(inputvalue, returnifgte, threshold)

Returns 0 if the value inputvalue is smaller than the threshold threshold, returnifgte otherwise. This function corresponds to the STEP function in the DYNAMO language.

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WorldDynamics.switchMethod

switch(returnifzero, returnifnotzero, inputvalue)

Returns returnifzero if the value inputvalue is approximately 0 with tolerance 1e-16, returnifnotzero otherwise. This function corresponds to the SWITCH (also called FIFZE) function in the DYNAMO language.

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Functions in plotvariables.jl

WorldDynamics.plotvariablesMethod

plotvariables(solution, xrange, variables::Vector{<:NTuple{4, Any}}; title="", showaxis=true, showlegend=true, linetype="lines", colored=true)

Plot the values of the variables in the vector variables obtained by the ODE system solution (normally, obtained by using the solve function in solvesystems.jl) in the specified xrange interval. For each variable, the vector variables includes a quadruple, containing the Julia variable, its range, and its symbolic name to be shown in the plot.

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Functions in solvesystems.jl

WorldDynamics.composeMethod

compose(systems::Vector{ODESystem}, connection_eqs::Vector{Equation})

Return the ODE system obtained by composing the ODE systems in the vector systems and by making use of the variable equalities in connection_eqs. Normally, each ODE systems in systems corresponds to a subsystem of a system in the World3 model, and the variable equalities specify which variables are shared between the subsystems.

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WorldDynamics.solveMethod

solve(system::ODESystem, timespan; solver=AutoVern9(Rodas5())

Return the solution of the system ODE system in the timespan interval (for the available different ODE system solvers, see the documentation of DifferentialEquations.jl).

We use the AutoVern9(Rodas5()) solver since it is among the suggested ones in the documentation of DifferentialEquations.jl, and among those we tested, it is the one that works best.

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Reproducing World1 figures

World1 system

WorldDynamics.World1.fig_1Method
Reproduce Fig. W1-7/5-1. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
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WorldDynamics.World1.fig_10Method
Reproduce Fig. W1-7/5-10. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_11Method
Reproduce Fig. W1-7/5-11. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_12Method
Reproduce Fig. W1-7/5-12. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_2Method
Reproduce Fig. W1-7/5-2. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_3Method
Reproduce Fig. W1-7/5-3. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_4Method
Reproduce Fig. W1-7/5-4. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_5Method
Reproduce Fig. W1-7/5-5. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_6Method
Reproduce Fig. W1-7/5-6. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_7Method
Reproduce Fig. W1-7/5-7. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_8Method
Reproduce Fig. W1-7/5-8. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
source
WorldDynamics.World1.fig_9Method
Reproduce Fig. W1-7/5-9. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
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WorldDynamics.World1.fig_stdMethod
Reproduce Fig. WORLD1-STD. The original figure is presented in the MIT memorandum D-1348 of [World1](https://dome.mit.edu/handle/1721.3/189645).
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Reproducing World2 figures

World2 system

WorldDynamics.World2.fig_4_1Method
Reproduce Fig. 4-1. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Basic behavior of the world model, showing the mode in which industrialization and population are suppressed by falling natural resources.
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WorldDynamics.World2.fig_4_10Method
Reproduce Fig. 4-10. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: System ratios when growth is suppressed by crowding.
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WorldDynamics.World2.fig_4_11Method
Reproduce Fig. 4-11. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Food shortage as the only remaining pressure to stop population growth.
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WorldDynamics.World2.fig_4_12Method
Reproduce Fig. 4-12. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: System ratios during the food-shortage mode.
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WorldDynamics.World2.fig_4_2Method
Reproduce Fig. 4-2. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Original model as in Fig. 4-1. Material standard of living reaches a maximum and then declines as natural resources are depleted.
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WorldDynamics.World2.fig_4_3Method
Reproduce Fig. 4-3. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Original model as in Fig 4-1. Natural-resource-usage rate reaches a peak about year 2010 and declines as natural resources, population, and capital investment decline.
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WorldDynamics.World2.fig_4_4Method
Reproduce Fig. 4-4. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption:Original model as in Fig. 4-1. The rate of capital-investment generation declines after 2010 but does not fall below the rate of capital-investment discard until 2040, at which time the level of capital investment begins to decline.
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WorldDynamics.World2.fig_4_5Method
Reproduce Fig. 4-5. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Reduced usage rate of natural resources leads to a pollution crisis.
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WorldDynamics.World2.fig_4_6Method
Reproduce Fig. 4-6. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: System ratios during the pollution mode of growth suppression.
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WorldDynamics.World2.fig_4_7Method
Reproduce Fig. 4-7. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Dynamics of the pollution sector. A positive-feedback growth in pollution occurs when the pollution-absorption time increases faster than the pollution.
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WorldDynamics.World2.fig_4_8Method
Reproduce Fig. 4-8. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Population sector during the pollution mode.
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WorldDynamics.World2.fig_4_9Method
Reproduce Fig. 4-9. The original figure is presented in Chapter 4 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Growth suppressed by crowding when natural resources and pollution are inactive.
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WorldDynamics.World2.fig_5_1Method
Reproduce Fig. 5-1. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Higher capital-investment generation triggers the pollution crisis.
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WorldDynamics.World2.fig_5_10Method
Reproduce Fig. 5-10. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Ratios for the conditions of Fig. 5-9. Higher food productivity causes capital reallocation away from agriculture.
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WorldDynamics.World2.fig_5_11Method
Reproduce Fig. 5-11. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Increased food production causes greater population and earlier pollution crisis compared with Fig. 5-8.
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WorldDynamics.World2.fig_5_12Method
Reproduce Fig. 5-12. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Compared with Fig. 5-11, increased capital generation causes an earlier pollution crisis.
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WorldDynamics.World2.fig_5_13Method
Reproduce Fig. 5-13. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Compared with Fig. 5-12, less pollution generation increases peak population and delays the pollution crisis.
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WorldDynamics.World2.fig_5_14Method
Reproduce Fig. 5-14. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Compared with Fig. 5-12, reduced birth rate lowers the peak population but does not ellminate or delay the pollution crisis.
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WorldDynamics.World2.fig_5_2Method
Reproduce Fig. 5-2. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Lower birth rate does not affect suppression of growth by falling natural resources.
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WorldDynamics.World2.fig_5_3Method
Reproduce Fig. 5-3. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Ratios for the same condition of lower birth rate as in Fig. 5-2.
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WorldDynamics.World2.fig_5_4Method
Reproduce Fig. 5-4. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Reduced birth rate still leads to the pollution crisis.
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WorldDynamics.World2.fig_5_5Method
Reproduce Fig. 5-5. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: With resource depletion and pollution suppressed, population still climbs even with a 30% reduction in "normal" birth rate.
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WorldDynamics.World2.fig_5_6Method
Reproduce Fig. 5-6. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: A 50% reduction in "normal" birth rate causes growth of population to pause for 20 years, then resume.
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WorldDynamics.World2.fig_5_7Method
Reproduce Fig. 5-7. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Ratios for conditions of Fig. 5-6.
source
WorldDynamics.World2.fig_5_8Method
Reproduce Fig. 5-8. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Reduction of pollution generation allows population and capital investment to increase further before the pollution crisis.
source
WorldDynamics.World2.fig_5_9Method
Reproduce Fig. 5-9. The original figure is presented in Chapter 5 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Increased food production causes increased population.
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WorldDynamics.World2.fig_6_1Method
Reproduce Fig. 6-1. The original figure is presented in Chapter 6 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Natural-resource-usage rate and pollution generation are reduced in 1970.
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WorldDynamics.World2.fig_6_2Method
Reproduce Fig. 6-2. The original figure is presented in Chapter 6 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Ratios for conditions of Fig. 6-1.
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WorldDynamics.World2.fig_6_3Method
Reproduce Fig. 6-3. The original figure is presented in Chapter 6 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Capital generation is reduced 40% in 1970 in addition to changes in Fig. 6-1. Population
stabilizes at a lower level; quality of life is increased.
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WorldDynamics.World2.fig_6_4Method
Reproduce Fig. 6-4. The original figure is presented in Chapter 6 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Ratios for conditions of Fig. 6-3.
source
WorldDynamics.World2.fig_6_5Method
Reproduce Fig. 6-5. The original figure is presented in Chapter 6 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Food productivity is reduced 20% in 1970 along with changes in Fig. 6-3. Population is lower, quality of life higher.
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WorldDynamics.World2.fig_6_6Method
Reproduce Fig. 6-6. The original figure is presented in Chapter 6 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Ratios for conditions of Fig. 6-5.
source
WorldDynamics.World2.fig_6_7Method
Reproduce Fig. 6-7. The original figure is presented in Chapter 6 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Normal birth rate reduced 30% in 1970 along with changes in Fig. 6-5. Population is lower, quality of life higher again.
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WorldDynamics.World2.fig_6_8Method
Reproduce Fig. 6-8. The original figure is presented in Chapter 6 of [WD](https://archive.org/details/worlddynamics00forr).

Caption: Ratios for conditions of Fig. 6-7.
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Reproducing World3 figures

Agriculture system

WorldDynamics.World3.Agriculture.fig_69aMethod
Reproduce Fig 4.69a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-1: historical run.
The behavior of land yields and food production.
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WorldDynamics.World3.Agriculture.fig_69bMethod
Reproduce Fig 4.69b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-1: historical run.
The behavior of arable land.
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WorldDynamics.World3.Agriculture.fig_69cMethod
Reproduce Fig 4.69c. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-1: historical run.
The allocation mechanism.
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WorldDynamics.World3.Agriculture.fig_69dMethod
Reproduce Fig 4.69d. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-1: historical run.
The behavior of land fertility.
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WorldDynamics.World3.Agriculture.fig_70aMethod
Reproduce Fig 4.70a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-2: standard run.
The behavior of land yields and food production.
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WorldDynamics.World3.Agriculture.fig_70bMethod
Reproduce Fig 4.70b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-2: standard run.
The behavior of arable land.
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WorldDynamics.World3.Agriculture.fig_70cMethod
Reproduce Fig 4.70c. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-2: standard run.
The allocation mechanism.
source
WorldDynamics.World3.Agriculture.fig_70dMethod
Reproduce Fig 4.70d. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-2: standard run.
The behavior of land fertility.
source
WorldDynamics.World3.Agriculture.fig_72aMethod
Reproduce Fig 4.72a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-3: sensitivity test of the land yield multiplier from capital table, using the optimistic LYMCT.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_72bMethod
Reproduce Fig 4.72b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-3: sensitivity test of the land yield multiplier from capital table, using the optimistic LYMCT.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_73aMethod
Reproduce Fig 4.73a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-4: sensitivity test of the land yield multiplier from capital table, using the pessimistic LYMCT.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_73bMethod
Reproduce Fig 4.73b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-4: sensitivity test of the land yield multiplier from capital table, using the pessimistic LYMCT.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_74aMethod
Reproduce Fig 4.74a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-5: sensitivity test with a 35 percent increase in the estimate of the value of potentially arable land total.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_74bMethod
Reproduce Fig 4.74b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-5: sensitivity test with a 35 percent increase in the estimate of the value of potentially arable land total.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_75aMethod
Reproduce Fig 4.75a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-6: sensitivity test with a 25 percent decrease in the estimate of the value of potentially arable land total.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_75bMethod
Reproduce Fig 4.75b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-6: sensitivity test with a 25 percent decrease in the estimate of the value of potentially arable land total.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_76aMethod
Reproduce Fig 4.76a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-7: sensitivity test with a 35 percent increase in the estimate of the value of potentially arable land total and development costs adjusted to maintain historical behavior.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_76bMethod
Reproduce Fig 4.76b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-7: sensitivity test with a 35 percent increase in the estimate of the value of potentially arable land total and development costs adjusted to maintain historical behavior.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_77aMethod
Reproduce Fig 4.77a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-8: sensitivity test with a 35 percent increase in the estimate of the value of potentially arable land total and a 50 percent increase in the upper limit of the land yield multiplier from capital.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_77bMethod
Reproduce Fig 4.77b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-8: sensitivity test with a 35 percent increase in the estimate of the value of potentially arable land total and a 50 percent increase in the upper limit of the land yield multiplier from capital.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_78aMethod
Reproduce Fig 4.78a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-9: sensitivity test with a 25 percent decrease in the estimate of the value of potentially arable land total and a 25 percent decrease in the upper limit of the land yield multiplier from capital.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_78bMethod
Reproduce Fig 4.78b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-9: sensitivity test with a 25 percent decrease in the estimate of the value of potentially arable land total and a 25 percent decrease in the upper limit of the land yield multiplier from capital.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_82aMethod
Reproduce Fig 4.82a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-10: sensitivity test with optimistic estimates of the cost of land development, the adverse effects of air pollution on yield, and the extent to which high land yield causes land erosion.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_82bMethod
Reproduce Fig 4.82b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-10: sensitivity test with optimistic estimates of the cost of land development, the adverse effects of air pollution on yield, and the extent to which high land yield causes land erosion.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_83aMethod
Reproduce Fig 4.83a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-11: sensitivity test with pessimistic estimates of the cost of land development, the adverse effects of air pollution on yield, and the extent to which high land yield causes land erosion.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_83bMethod
Reproduce Fig 4.83b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-11: sensitivity test with pessimistic estimates of the cost of land development, the adverse effects of air pollution on yield, and the extent to which high land yield causes land erosion.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_84aMethod
Reproduce Fig 4.84a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-12: policy run in which the impairment of land fertility from
persistent pollutants is completely eliminated in 1975.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_84bMethod
Reproduce Fig 4.84b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-12: policy run in which the impairment of land fertility from
persistent pollutants is completely eliminated in 1975.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_85aMethod
Reproduce Fig 4.85a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-13: policy run in which the adverse effects of air pollution on land yield and the impairment of land fertility by persistent pollutants are completely eliminated in 1975.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_85bMethod
Reproduce Fig 4.85b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-13: policy run in which the adverse effects of air pollution on land yield and the impairment of land fertility by persistent pollutants are completely eliminated in 1975.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_86aMethod
Reproduce Fig 4.86a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-14: policy run in which efforts to combat land erosion are initiated in 1975, in addition to the previous policies that eliminate the adverse effects of air pollution and persistent pollution.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_86bMethod
Reproduce Fig 4.86b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-14: policy run in which efforts to combat land erosion are initiated in 1975, in addition to the previous policies that eliminate the adverse effects of air pollution and persistent pollution.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_87aMethod
Reproduce Fig 4.87a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-15: policy run in which the land required for urban and industrial use is reduced to 25 percent of expected requirements, in addition to the previous policies that combat land erosion and eliminate the adverse effects of air pollution and persistent pollution.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_87bMethod
Reproduce Fig 4.87b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-15: policy run in which the land required for urban and industrial use is reduced to 25 percent of expected requirements, in addition to the previous policies that combat land erosion and eliminate the adverse effects of air pollution and persistent pollution.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_88aMethod
Reproduce Fig 4.88a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-16: equilibrium run in which the exogenous inputs level off in the year 2050.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_88bMethod
Reproduce Fig 4.88b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-16: equilibrium run in which the exogenous inputs level off in the year 2050.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_89aMethod
Reproduce Fig 4.89a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-17: equilibrium run in which the exogenous inputs level off in the year 2025.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_89bMethod
Reproduce Fig 4.89b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-17: equilibrium run in which the exogenous inputs level off in the year 2025.
The behavior of arable land.
source
WorldDynamics.World3.Agriculture.fig_90aMethod
Reproduce Fig 4.90a. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 4-18: equilibrium run in which the exogenous inputs level off in the year 2000.
The behavior of land yields and food production.
source
WorldDynamics.World3.Agriculture.fig_90bMethod
Reproduce Fig 4.90b. The original figure is presented in Chapter 4 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption:  Run 4-18: equilibrium run in which the exogenous inputs level off in the year 2000.
The behavior of arable land.
source

Capital system

WorldDynamics.World3.Capital.fig_36Method
Reproduce Fig 3.36. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Driving functions for the standard run of the capital sector.
source
WorldDynamics.World3.Capital.fig_37Method
Reproduce Fig 3.37. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 3-1: standard run of the capital sector with exogenous inputs.
source
WorldDynamics.World3.Capital.fig_38Method
Reproduce Fig 3.38. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 3-2: behavior of the capital sector when the average lifetime of industrial capital is increased from 14 to 21 years with standard inputs.
source
WorldDynamics.World3.Capital.fig_39Method
Reproduce Fig 3.39. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run3-3: behaviorofthecapital sector when the capital-output ratio is decreased from 3 to 2 years with standard inputs.
source
WorldDynamics.World3.Capital.fig_40Method
Reproduce Fig 3.40. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 3-4: behavior of the capital sector when the industrial capital-output ratio is increased from 3 to 4 years with standard inputs.
Note: Scales for IOPC, SOPC, and IO have been changed from their normal values.
source
WorldDynamics.World3.Capital.fig_41Method
Reproduce Fig 3.41. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 3-5: behavior of the capital sector when the fraction of capital allocated to obtaining resources is increased from 0.05 to 0.35 with other inputs at their standard values.
Note: Scales for IOPC, SOPC, and IO have been changed from their normal values.
source
WorldDynamics.World3.Capital.fig_42Method
Reproduce Fig 3.42. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 3-6: behavior of the capital sector when the service capital-output ratio is increased from 1 to 2 years with standard inputs.
source
WorldDynamics.World3.Capital.fig_43Method
Reproduce Fig 3.43. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Driving functions for capital sector experiencing increasing resource costs.
source
WorldDynamics.World3.Capital.fig_44Method
Reproduce Fig 3.44. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 3-7: behavior of the capital sector when the fraction of capital allocated to obtaining resources increases after 1970.
source
WorldDynamics.World3.Capital.fig_45Method
Reproduce Fig 3.45. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Driving functions for capital sector undergoing increasing food. costs
source
WorldDynamics.World3.Capital.fig_46Method
Reproduce Fig 3.46. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 3-8: behavior of the capital sector when the fraction of industrial output allocated to agriculture increases after 1970.
source
WorldDynamics.World3.Capital.fig_47Method
Reproduce Fig 3.47. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Driving functions for a population decline in the capital sector.
source
WorldDynamics.World3.Capital.fig_48Method
Reproduce Fig 3.48. The original figure is presented in Chapter 3 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 3-9: behavior of the capital sector when the
population declines after 1970.
source

Non-Renewable system

WorldDynamics.World3.NonRenewable.fig_25Method
Reproduce Fig 5.25. The original figure is presented in Chapter 5 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 5-1: standard run for the nonrenewable resource sector.
source
WorldDynamics.World3.NonRenewable.fig_26Method
Reproduce Fig 5.26. The original figure is presented in Chapter 5 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 5-2: Behavior of the sector with double the initial value of nonrenewable resources.
source
WorldDynamics.World3.NonRenewable.fig_28Method
Reproduce Fig 5.28. The original figure is presented in Chapter 5 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 5-3: The effects of cost-reducing technologies on the behavior of the nonrenewable resource sector.
source
WorldDynamics.World3.NonRenewable.fig_29Method
Reproduce Fig 5.29. The original figure is presented in Chapter 5 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 5-4: the effects of resource-conserving technologies on the behavior of the nonrenewable resource sector.
source
WorldDynamics.World3.NonRenewable.fig_30Method
Reproduce Fig 5.30. The original figure is presented in Chapter 5 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 5-5: The effects of zero population growth and advanced technological policies on the behavior of the nonrenewable resource sector.
source

Pollution system

WorldDynamics.World3.Pollution.fig_26Method
Reproduce Fig 6.26. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-1: behavior of the pollution sector in response to a pulse input in persistent pollution generation in 1920.
source
WorldDynamics.World3.Pollution.fig_27Method
Reproduce Fig 6.27. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-2: behavior of the pollution sector in response to a step increase and decrease in persistent pollution generation.
source
WorldDynamics.World3.Pollution.fig_28Method
Reproduce Fig 6.28. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Inputs to Run 6-3, the historical run of the pollution sector.
source
WorldDynamics.World3.Pollution.fig_29Method
Reproduce Fig 6.29. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-3: historical run of the pollution sector.
source
WorldDynamics.World3.Pollution.fig_30Method
Reproduce Fig 6.30. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Inputs to Run 6-4 of the pollution sector when continued material growth is assumed.
source
WorldDynamics.World3.Pollution.fig_31Method
Reproduce Fig 6.31. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-4: behavior of the pollution sector in response to continued material growth.
source
WorldDynamics.World3.Pollution.fig_32Method
Reproduce Fig 6.32. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-5: behavior of the pollution sector with decreased toxicity indices.
source
WorldDynamics.World3.Pollution.fig_33Method
Reproduce Fig 6.33. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-6: behavior of the pollution sector when the estimate of the persistent pollution transmission delay is doubled.
source
WorldDynamics.World3.Pollution.fig_34Method
Reproduce Fig 6.34. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-7: behavior of the pollution sector when the estimate of the persistent pollution transmission delay is halved.
source
WorldDynamics.World3.Pollution.fig_35Method
Reproduce Fig 6.35. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-8: behavior of the pollution sector when the assimilation half-life is assumed to increase twice as fast with a rising index of persistent pollution.
source
WorldDynamics.World3.Pollution.fig_36Method
Reproduce Fig 6.36. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-9: behavior of the pollution sector when the assimilation half-life is assumed to be constant.
source
WorldDynamics.World3.Pollution.fig_37Method
Reproduce Fig 6.37. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-10: behavior of the pollution sector in response to a doubling of the persistent pollution transmission delay in 1975.
source
WorldDynamics.World3.Pollution.fig_38Method
Reproduce Fig 6.38. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-11: behavior of the pollution sector in response to an advance in persistent pollution assimilation technology in 1975.
source
WorldDynamics.World3.Pollution.fig_39Method
Reproduce Fig 6.39. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-12: behavior of the pollution sector in response to a 50 percent increase in human health and land fertility technology in 1975.
source
WorldDynamics.World3.Pollution.fig_40Method
Reproduce Fig 6.40. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-13: behavior of the pollution sector in response to a sudden increase in persistent pollution generation control technology in 1975.
source
WorldDynamics.World3.Pollution.fig_41Method
Reproduce Fig 6.41. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-14: behavior of the pollution sector in response to adaptive persistent pollution generation control technologies when the persistent pollution transmission delay is assumed to be 20 years.
source
WorldDynamics.World3.Pollution.fig_43Method
Reproduce Fig 6.43. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-15: behavior of the pollution sector in response to adaptive persistent pollution generation control technologies when the persistent pollution transmission delay is assumed to be 2 years.
source
WorldDynamics.World3.Pollution.fig_44Method
Reproduce Fig 6.44. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-16: behavior of the pollution sector when persistent pollution generation stabilizes in the year 2000.
source
WorldDynamics.World3.Pollution.fig_45Method
Reproduce Fig 6.45. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-17: behavior of the pollution sector when persistent pollution generation stabilizes in the year 2020.
source
WorldDynamics.World3.Pollution.fig_46Method
Reproduce Fig 6.46. The original figure is presented in Chapter 6 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 6-18: behavior of the pollution sector when adaptive persistent pollution generation control technologies are combined with material equilibrium in the year 2020.
source

One level population system

WorldDynamics.World3.Pop1.fig_100Method
Reproduce Fig 2.100. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2- 15: constant total output, perfect fertility control, reduced desired family size.
source
WorldDynamics.World3.Pop1.fig_103aMethod
Reproduce Fig 2.103a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-18: maximum life expectancy of 100 years.
source
WorldDynamics.World3.Pop1.fig_103bMethod
Reproduce Fig 2.103b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-18: maximum life expectancy of 100 years.
source
WorldDynamics.World3.Pop1.fig_103cMethod
Reproduce Fig 2.103c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-18: maximum life expectancy of 100 years.
source
WorldDynamics.World3.Pop1.fig_84Method
Reproduce Fig 2.84. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-1: historical behavior, 1900-1975.
source
WorldDynamics.World3.Pop1.fig_85Method
Reproduce Fig 2.85. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2—2: historical behavior, 1900—1975, mortality variables.
source
WorldDynamics.World3.Pop1.fig_86Method
Reproduce Fig 2.86. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-3: historical behavior, 1900-1975, fertility variables.
source
WorldDynamics.World3.Pop1.fig_87Method
Reproduce Fig 2.87. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-4: constant low income.
source
WorldDynamics.World3.Pop1.fig_88Method
Reproduce Fig 2.88. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-5: constant high income.
source
WorldDynamics.World3.Pop1.fig_89Method
Reproduce Fig 2.89. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-6: constant low income, improved health care.
source
WorldDynamics.World3.Pop1.fig_90Method
Reproduce Fig 2.90. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-7: exponential economic growth.
source
WorldDynamics.World3.Pop1.fig_91Method
Reproduce Fig 2.91. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-8: exponential economic growth, mortality variables.
source
WorldDynamics.World3.Pop1.fig_93Method
Reproduce Fig 2.93. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-9: exponential economic growth, fertility variables.
source
WorldDynamics.World3.Pop1.fig_96Method
Reproduce Fig 2.96. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-11: exponential economic growth, perfect fertility control.
source
WorldDynamics.World3.Pop1.fig_97Method
Reproduce Fig 2.97. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-12: exponential economic growth, perfect fertility control, reduced desired family size.
source
WorldDynamics.World3.Pop1.fig_98Method
Reproduce Fig 2.98. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-13: constant total output.
source
WorldDynamics.World3.Pop1.fig_99Method
Reproduce Fig 2.99. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-14: constant total output, perfect fertility control.
source

Four level population system

WorldDynamics.World3.Pop4.fig_100Method
Reproduce Fig 2.100. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2- 15: constant total output, perfect fertility control, reduced desired family size.
source
WorldDynamics.World3.Pop4.fig_101aMethod
Reproduce Fig 2.101a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-16: constant total output, reference for sensitivity tests.
source
WorldDynamics.World3.Pop4.fig_101bMethod
Reproduce Fig 2.101b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-16: constant total output, reference for sensitivity tests.
source
WorldDynamics.World3.Pop4.fig_101cMethod
Reproduce Fig 2.101c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-16: constant total output, reference for sensitivity tests.
source
WorldDynamics.World3.Pop4.fig_102aMethod
Reproduce Fig 2.102a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-17: equitable food distribution and nutrition education.
source
WorldDynamics.World3.Pop4.fig_102bMethod
Reproduce Fig 2.102b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-17: equitable food distribution and nutrition education.
source
WorldDynamics.World3.Pop4.fig_102cMethod
Reproduce Fig 2.102c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-17: equitable food distribution and nutrition education.
source
WorldDynamics.World3.Pop4.fig_104aMethod
Reproduce Fig 2.104a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-19: greater allocations to health services.
source
WorldDynamics.World3.Pop4.fig_104bMethod
Reproduce Fig 2.104b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-19: greater allocations to health services.
source
WorldDynamics.World3.Pop4.fig_104cMethod
Reproduce Fig 2.104c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-19: greater allocations to health services.
source
WorldDynamics.World3.Pop4.fig_105aMethod
Reproduce Fig 2.105a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-20: no crowding effect.
source
WorldDynamics.World3.Pop4.fig_105bMethod
Reproduce Fig 2.105b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-20: no crowding effect.
source
WorldDynamics.World3.Pop4.fig_105cMethod
Reproduce Fig 2.105c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-20: no crowding effect.
source
WorldDynamics.World3.Pop4.fig_106aMethod
Reproduce Fig 2.106a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-21: constant maximum total fertility.
source
WorldDynamics.World3.Pop4.fig_106bMethod
Reproduce Fig 2.106b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-21: constant maximum total fertility.
source
WorldDynamics.World3.Pop4.fig_106cMethod
Reproduce Fig 2.106c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-21: constant maximum total fertility.
source
WorldDynamics.World3.Pop4.fig_107aMethod
Reproduce Fig 2.107a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-22: lower family size norm.
source
WorldDynamics.World3.Pop4.fig_107bMethod
Reproduce Fig 2.107b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-22: lower family size norm.
source
WorldDynamics.World3.Pop4.fig_107cMethod
Reproduce Fig 2.107c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-22: lower family size norm.
source
WorldDynamics.World3.Pop4.fig_108aMethod
Reproduce Fig 2.108a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-23: constant family size norm of 3.
source
WorldDynamics.World3.Pop4.fig_108bMethod
Reproduce Fig 2.108b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-23: constant family size norm of 3.
source
WorldDynamics.World3.Pop4.fig_108cMethod
Reproduce Fig 2.108c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-23: constant family size norm of 3.
source
WorldDynamics.World3.Pop4.fig_109aMethod
Reproduce Fig 2.109a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-24: increased social adjustment delay.
source
WorldDynamics.World3.Pop4.fig_109bMethod
Reproduce Fig 2.109b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-24: increased social adjustment delay.
source
WorldDynamics.World3.Pop4.fig_109cMethod
Reproduce Fig 2.109c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-24: increased social adjustment delay.
source
WorldDynamics.World3.Pop4.fig_110aMethod
Reproduce Fig 2.110a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-25: no income expectation effect.
source
WorldDynamics.World3.Pop4.fig_110bMethod
Reproduce Fig 2.110b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-25: no income expectation effect.
source
WorldDynamics.World3.Pop4.fig_110cMethod
Reproduce Fig 2.110c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-25: no income expectation effect.
source
WorldDynamics.World3.Pop4.fig_111aMethod
Reproduce Fig 2.111a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-26: increased compensation for perceived life expectancy.
source
WorldDynamics.World3.Pop4.fig_111bMethod
Reproduce Fig 2.111b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-26: increased compensation for perceived life expectancy.
source
WorldDynamics.World3.Pop4.fig_111cMethod
Reproduce Fig 2.111c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-26: increased compensation for perceived life expectancy.
source
WorldDynamics.World3.Pop4.fig_112aMethod
Reproduce Fig 2.112a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-27: decreased lifetime perception delay.
source
WorldDynamics.World3.Pop4.fig_112bMethod
Reproduce Fig 2.112b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-27: decreased lifetime perception delay.
source
WorldDynamics.World3.Pop4.fig_112cMethod
Reproduce Fig 2.112c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-27: decreased lifetime perception delay.
source
WorldDynamics.World3.Pop4.fig_113aMethod
Reproduce Fig 2.113a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-28: decreased fertility control effectiveness.
source
WorldDynamics.World3.Pop4.fig_113bMethod
Reproduce Fig 2.113b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-28: decreased fertility control effectiveness.
source
WorldDynamics.World3.Pop4.fig_113cMethod
Reproduce Fig 2.113c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-28: decreased fertility control effectiveness.
source
WorldDynamics.World3.Pop4.fig_84Method
Reproduce Fig 2.84. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-1: historical behavior, 1900-1975.
source
WorldDynamics.World3.Pop4.fig_85Method
Reproduce Fig 2.85. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2—2: historical behavior, 1900—1975, mortality variables.
source
WorldDynamics.World3.Pop4.fig_86Method
Reproduce Fig 2.86. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-3: historical behavior, 1900-1975, fertility variables.
source
WorldDynamics.World3.Pop4.fig_87Method
Reproduce Fig 2.87. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-4: constant low income.
source
WorldDynamics.World3.Pop4.fig_88Method
Reproduce Fig 2.88. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-5: constant high income.
source
WorldDynamics.World3.Pop4.fig_89Method
Reproduce Fig 2.89. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-6: constant low income, improved health care.
source
WorldDynamics.World3.Pop4.fig_90Method
Reproduce Fig 2.90. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-7: exponential economic growth.
source
WorldDynamics.World3.Pop4.fig_91Method
Reproduce Fig 2.91. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-8: exponential economic growth, mortality variables.
source
WorldDynamics.World3.Pop4.fig_93Method
Reproduce Fig 2.93. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-9: exponential economic growth, fertility variables.
source
WorldDynamics.World3.Pop4.fig_96Method
Reproduce Fig 2.96. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-11: exponential economic growth, perfect fertility control.
source
WorldDynamics.World3.Pop4.fig_97Method
Reproduce Fig 2.97. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-12: exponential economic growth, perfect fertility control, reduced desired family size.
source
WorldDynamics.World3.Pop4.fig_98Method
Reproduce Fig 2.98. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-13: constant total output.
source
WorldDynamics.World3.Pop4.fig_99Method
Reproduce Fig 2.99. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-14: constant total output, perfect fertility control.
source

Fifteen level population system

WorldDynamics.World3.Pop15.fig_100Method
Reproduce Fig 2.100. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2- 15: constant total output, perfect fertility control, reduced desired family size.
source
WorldDynamics.World3.Pop15.fig_84Method
Reproduce Fig 2.84. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-1: historical behavior, 1900-1975.
source
WorldDynamics.World3.Pop15.fig_85Method
Reproduce Fig 2.85. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2—2: historical behavior, 1900—1975, mortality variables.
source
WorldDynamics.World3.Pop15.fig_86Method
Reproduce Fig 2.86. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-3: historical behavior, 1900-1975, fertility variables.
source
WorldDynamics.World3.Pop15.fig_87Method
Reproduce Fig 2.87. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-4: constant low income.
source
WorldDynamics.World3.Pop15.fig_88Method
Reproduce Fig 2.88. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-5: constant high income.
source
WorldDynamics.World3.Pop15.fig_89Method
Reproduce Fig 2.89. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-6: constant low income, improved health care.
source
WorldDynamics.World3.Pop15.fig_90Method
Reproduce Fig 2.90. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-7: exponential economic growth.
source
WorldDynamics.World3.Pop15.fig_91Method
Reproduce Fig 2.91. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-8: exponential economic growth, mortality variables.
source
WorldDynamics.World3.Pop15.fig_93Method
Reproduce Fig 2.93. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-9: exponential economic growth, fertility variables.
source
WorldDynamics.World3.Pop15.fig_94aMethod
Reproduce Fig 2.94a. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-10: exponential economic growth, higher childbearing age.
source
WorldDynamics.World3.Pop15.fig_94bMethod
Reproduce Fig 2.94b. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-10: exponential economic growth, higher childbearing age.
source
WorldDynamics.World3.Pop15.fig_94cMethod
Reproduce Fig 2.94c. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-10: exponential economic growth, higher childbearing age.
source
WorldDynamics.World3.Pop15.fig_96Method
Reproduce Fig 2.96. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-11: exponential economic growth, perfect fertility control.
source
WorldDynamics.World3.Pop15.fig_97Method
Reproduce Fig 2.97. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-12: exponential economic growth, perfect fertility control, reduced desired family size.
source
WorldDynamics.World3.Pop15.fig_98Method
Reproduce Fig 2.98. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-13: constant total output.
source
WorldDynamics.World3.Pop15.fig_99Method
Reproduce Fig 2.99. The original figure is presented in Chapter 2 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 2-14: constant total output, perfect fertility control.
source

World3 system

WorldDynamics.World3.fig_10Method
Reproduce Fig 7.10. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-7: sensitivity of the initial value of nonrenewable resources to a doubling of NRI.
To test the sensitivity of the reference run (Figure 7.7) to an error in the estimate of initial nonrenewable resources, NRI is doubled. As a result, industrialization continues for an additional 15 years until growth is again halted by the effects of resource depletion.
source
WorldDynamics.World3.fig_11Method
Reproduce Fig 7.11. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-8: sensitivity of the initial value of nonrenewable resources to a tenfold increase in NRI.
The initial value of nonrenewable resources NRI is increased by a factor
of 10, to a value well outside its most likely range. Under this optimistic
assumption, the effects of nonrenewable resource depletion are no longer
a constraint to growth. Note that there is no dynamic difference in this
run between setting resources at 10 times their reference value or assum¬
ing an infinite value of resources. However, population and capital con¬
tinue to grow until constrained by the rising level of pollution.
source
WorldDynamics.World3.fig_13Method
Reproduce Fig 7.13. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-9: sensitivity of the fraction of industrial output allocated to agriculture.
The slope of the fraction of industrial output allocated to agriculture
FIOAA relationship is increased, reducing the time needed to redirect
industrial output into or out of agricultural investment. This change has
very little effect on the overall behavior of the model.
source
WorldDynamics.World3.fig_14Method
Reproduce Fig 7.14. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-10: sensitivity of the average lifetime of industrial capital.
The average lifetime of industrial capital ALIC is increased 50 percent
over its value in the reference run (from 14 years to 21 years), causing
capital to grow faster than in the reference run. Although the behavior
mode of the model is unchanged, the model variables do not pass through
their 1970 historical values. This parameter, as well as the other
parameters in the capital growth loop, is an important factor in determining the growth rate of capital.
source
WorldDynamics.World3.fig_15Method
Reproduce Fig 7.15. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-11: sensitivity of the average lifetime of industrial capital and the industrial capital-output ratio.
As in the previous run, the average lifetime of industrial capital ALIC is
increased from 14 to 21 years. To ensure that the model duplicates
historical behavior, the industrial capital-output ratio ICOR is also increased (from 3 to 3.75). The resulting behavior is very similar to that of the reference run. Changes in the elements affecting capital growth, when
constrained to produce behavior consistent with historical behavior, do
not significantly affect the behavior of the model.
source
WorldDynamics.World3.fig_16Method
Reproduce Fig 7.16. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-12: improved resource exploration and extraction technologies.
The implementation of improved resource exploration and extraction
technologies in 1975 is modeled by lowering the capital cost of obtaining
resources for industrial production. This policy allows industrial production to continue growing for a few more years than in the reference run, but it is ineffective in avoiding the effects of resource depletion.
source
WorldDynamics.World3.fig_18Method
Reproduce Fig 7.18. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-13: recycling technologies.
The advances in resource exploration and extraction technologies of Run
7-12 are supplemented by an improvement in recycling technologies that
reduces per capita resource usage by a factor of eight in 1975. That
policy removes the constraining effects of resource depletion and allows
population and capital growth to continue until checked by persistent
pollution.
source
WorldDynamics.World3.fig_19Method
Reproduce Fig 7.19. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-14: resource and air pollution control technologies.
As resource technologies eliminate the resource constraint to growth,
industrial output continues to grow until it generates intolerable levels of
pollution. To decrease the constraining effects of pollution on the system,
Run 7-14 assumes that new air pollution control technologies are implemented in 1975. These additional technologies substantially reduce the
adverse effects of air pollution on land yield. However, land yield and
food per capita still decline, for the high index of persistent pollution
PPOLX decreases the land fertility. The improvement in air pollution
control technologies has solved only a small part of the pollution problem, for the rise in persistent pollutants ends growth in the other sectors of
the model.
source
WorldDynamics.World3.fig_2Method
Reproduce Fig 7.2. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-1: population sector behavior, 1900-1970.
Population POP increases over time at an average growth rate of 1.2 percent per year. Both the birth rate CBR and the death rate CDR decrease over the period, the former largely because of a lower desired total
fertility DTF, and the latter primarily as a result of increased health services LMHS. Both trends occur as a result of industrialization.
source
WorldDynamics.World3.fig_20Method
Reproduce Fig 7.20. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-15: resource and pollution technologies.
Note: The scale for lOPC has been increased from 1,000 to 2,000 dollars
per person-year.
The resource arid air pollution control technologies of the previous run
are augmented in 1975 by a technological policy that reduces by a factor
of 10 the index of persistent pollution PPOLX 'generated by each unit of
agricultural and industrial output. The lower level of pollution allows
population and industrial output to continue to grow until the amount of
available food becomes the constraining factor. The decline in food per
capita FPC eventually causes a reduction in both population POP and
industrial output per capita IOPC.
source
WorldDynamics.World3.fig_21Method
Reproduce Fig 7.21. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-16: resource, pollution, and land yield technologies.
Note: The scale of IOPC has been increased from 1,000 to 2,000 dollars
per person-year.
To increase food production, new agricultural technologies are implemented, augmenting the resource and pollution technologies of the previous run; they increase the land yield LY by a factor of 2 in 1975.
This policy successfully raises the level of food in the short run, but in the long run the high yields cause increased land erosion, which later decreases the available food. After the year 2050 the higher rate of erosion
depresses yields (and thus food per capita FPC) below the values observed in the previous run. As a result, population POP and industrial
output per capita IOPC decline earlier than in Run 7-15, which assumed
no new land yield technologies.
source
WorldDynamics.World3.fig_22Method
Reproduce Fig 7.22. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-17: resource, pollution, and agricultural technologies.
Note: The scale of IOPC has been increased from 1,000 to 8,000 dollars
per person-year.
The resource, pollution, and land yield technologies of the previous run
are supplemented in 1975 by an improvement in land maintenance technologies. These new technologies ensure that higher land yields do not
lead to any significant increase in land erosion. The reduced constraints in
the resource, pollution, and agriculture sectors allow population POP and
industrial output per capita IOPC to continue to grow until the effects of
resource depletion are again evident, as in the reference run. Both population POP and industrial output per capita IOPC decline after the year
2080.
source
WorldDynamics.World3.fig_23Method
Reproduce Fig 7.23. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-18: exponential changes in technology.
Here it is assumed that exponentially increasing technologies are able to
postpone indefinitely the effects of the constraints to growth, as modeled
in World3, at no cost and with no delays in development and implementation. The improved technologies tend to reduce per capita resource usage
and pollution generation per unit of agricultural and industrial output at 4
percent per year after 1975. At the same time, land yields tend to increase
at 4 percent per year, with no upper limit and with practically no adverse
side effects such as land erosion. Although industrialization grows exponentially, the rate of removal of land for urban-industrial use decreases to zero by the year 2000. Finally, air pollution is assumed to have no adverse effects on land yield. Under these assumptions, population
reaches 14 billion people in the year 2100 and continues to grow (though
at a slow rate of 0.6 percent per year). Food is in abundance throughout
the run resource usage declines to zero as fewer resources are needed to
sustain output, and industrial output per capita IOPC continues to grow
indefinitely.
source
WorldDynamics.World3.fig_24Method
Reproduce Fig 7.24. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-19: adaptive technological policies—no delays, no costs.
Technological advances in reducing per capita resource usage, diminishing pollution, and increasing land yield are assumed to occur in response
to a perceived need for the technologies. The maximum rate of change for
each technology is assumed to be 5 percent per year. In addition, discrete
advances in exploration and extraction technologies, land maintenance
technologies, and air pollution technologies are assumed to be implemented
in 1975. This run is similar in behavior to Run 7-18, in which technological
improvements rise continuously at 4 percent per year. Growth is maintained through the year 2100 because of the absence of significant delays
and costs in the development of new technologies.
source
WorldDynamics.World3.fig_26Method
Reproduce Fig 7.26. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-20: adaptive technological policies—the effects of limitations to technological capabilities.
The adaptive technological policies assumed in this run are identical to
those in Run 7-19 except that the maximum rate of technological change
is assumed to be 2 percent instead of 5 percent per year. Technology is
unable to avoid the effects of the constraints to growth because industrial
output per capita IOPC and population POP grow faster than the maximum rate of technological change. In this run, resource depletion again halts growth in population and industrial output.
source
WorldDynamics.World3.fig_27Method
Reproduce Fig 7.27. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-21: adaptive technological policies—the effects of technological development and implementation costs.
Here it is assumed that more effective recycling, pollution control, and
land yield advances can be obtained only at increasing costs. These
higher costs are represented in the model by a rise in the industrial
capital-output ratio I COR. A trade-off now occurs between the benefits of
continued growth and the costs of the technologies that make further
growth possible. The rising costs of the new technologies cause industrial
output per capita IOPC to decline after the year 2010.
source
WorldDynamics.World3.fig_3Method
Reproduce Fig 7.3. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-2: capital sector behavior, 1900-1970.
Industrial capital IC grows exponentially, causing industrial output IO to
grow. Since their growth rate is greater than that of population, industrial
output per capita IOPC also grows over the period, as do service output
per capita SOPC and food per capita (not graphed). As development proceeds, (1) the fraction of output in agriculture FOA declines, (2) FOA is
largely replaced by the increasing fraction of output in industry FOI, and
(3) the fraction of output in services FOS remains relatively constant, near
50 percent of total output.
source
WorldDynamics.World3.fig_30Method
Reproduce Fig 7.30. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-22: adaptive technological policies—the effects of delays and costs of technological development and implementation.
Advances in recycling, pollution control, and land yield technologies are
again assumed to be obtainable only at a finite cost. In addition, it is
assumed that the benefits of these technologies will not be realized until
10 years after their initiation. As in Run 7-21, the rising costs, modeled
as a rise in the industrial capital-output ratio ICOR, cause industrial
output per capita IOPC to decline. The added costs incurred by the continued implementation of new technologies even after IOPC has peaked
force IOPC to fall more precipitously than in Run 7-21.
source
WorldDynamics.World3.fig_32Method
Reproduce Fig 7.32. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-23: adaptive technological policies—the effects of delays and costs,with a bias for continued growth in industrial output per capita.
The previous run assumed that new recycling, pollution control, and land
yield technologies are developed in response to a perceived need for
them. Because of the time involved in technological development and
implementation, however, these new technologies were effective only after
a delay. Moreover, their development and implementation required additional capital, which increased the industrial capital-output ratio. In this
run, the assumptions of Run 7-22 are augmented with a societal bias
toward continued growth in industrial output per capita IOPC. Technological policies are implemented only as long as they do not hamper
continued growth in IOPC. This policy is effective in continuing growth
in the short run but counterproductive in the long run: the failure to implement the new technologies causes a significant depletion of resources
and growth is ultimately terminated.
source
WorldDynamics.World3.fig_34Method
Reproduce Fig 7.34. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-24: reduction of the desired completed family size.
To reduce the pressures of population growth in the reference run, the
desired completed family size is reduced to 2 children per family in 1975.
Population POP continues to grow gradually for 70 years because of the
delays inherent in the age structure. However, the effects of resource depletion again force the population to decline after 2040, as in the reference run. Since population growth is reduced, industrial output per capita IOPC and food per capita FPC rise more rapidly between 1975 and 2020
than in the reference run.
source
WorldDynamics.World3.fig_35Method
Reproduce Fig 7.35. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-25: increase of industrial and service capital lifetimes.
Both the average lifetime of industrial capital ALIC and the lifetime of
service capital ALSC are increased 50 percent in 1975, thereby extending
the productivity of capital. When implemented without additional policies
to reduce the capital investment rate, this policy proves to be counterproductive in the long run. Compared with the reference run, the extension of product lifetimes allows industrial output to grow more rapidly, leading to a quicker depletion of resources. The rise in resource costs forces industrial output per capita IOPC to decline earlier than in the reference run.
source
WorldDynamics.World3.fig_36Method
Reproduce Fig 7.36. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-26: shift in the choice of output forms.
The amount of food and services desired by the population per unit of
industrial output is increased by 50 percent in 1975. This shift in the
choice of output slows the growth in industrial capital and industrial
output, putting less pressure on the resource base. In the long run,
however, the continually rising population POP thwarts the effectiveness
of this policy, forcing a decline in industrial output per capita IOPC due
to resource depletion.
source
WorldDynamics.World3.fig_37Method
Reproduce Fig 7.37. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-27: population policy and shift of output choices.
A combination of social policies that cause a reduction of growth both in
population and in industrial capital is simulated in this run. In 1975 the
desired completed family size is reduced to 2 children per family and the
amount of services and food per unit of industrial output desired by the population is increased by 50 percent. The resulting behavior is substantially more stable than in the reference run, but the overshoot and decline mode is still evident. In World3, even these reduced levels of population and industrial capital cannot be sustained over the long term; new technological policies must be added to offset the effects of the limits to growth.
source
WorldDynamics.World3.fig_38Method
Reproduce Fig 7.38. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-28: equilibrium through discrete policy changes.
To obtain one example of a sustainable state of equilibrium, this run
combines discrete policy changes in both technology and social values.
To stabilize the population POP, the desired completed family size is
reduced to 2 children per family in 1975. The growth in industrial capital is reduced in 1990 by reinvesting only enough industrial output to keep industrial output per capita IOPC at a constant level. In addition, new recycling and pollution control technologies are developed, capital lifetimes are increased, and social choices of output forms are shifted toward a preference for food and services. Population POP stabilizes in 2050 at 5 billion people, industrial output per capita IOPC levels off in 1990 at 350 dollars per person-year, and food per capita FPC stabilizes by the year 2000 at three times the subsistence level. The index of persistent pollution PPOLX is kept at very low levels, and the rate of resource depletion is slow enough to permit technology and industrial processes to adjust to changes in the availability of resources.
source
WorldDynamics.World3.fig_39Method
Reproduce Fig 7.39. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-29: equilibrium through adaptive policies.
Adaptive technological policies that increase resource recycling, reduce
persistent pollution generation, and increase land yields are combined
with social policies that stabilize population POP and industrial output
per capita IOPC. The technological advances in recycling, pollution control , and land yields are assumed to be effective only after a delay and to require capital for their development and implementation. As in the adaptive technological runs described in section 7.5, additional technologies are assumed to be implemented in 1975. These policies lower resource costs, decrease the effects of air pollution, and reduce land erosion. The resulting model behavior reaches equilibrium because the stable population and capital reduce the need for new technologies. Thus the newly implemented technologies are less costly, and the delays in their development and implementation are less critical to their effectiveness.
source
WorldDynamics.World3.fig_4Method
Reproduce Fig 7.4. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-3: agriculture sector behavior, 1900-1970.
Increases in arable land AL and land yields LY cause a rise in food
production over the historical period. The increase in land yields is
primarily attributable to greater agricultural inputs per hectare AIPH (fertilizers, pesticides), for the land fertility LFERT remains nearly constant.
Food per capita FPC also grows during the 70-year period but at a much
slower rate than total food F, since the population is also increasing.
source
WorldDynamics.World3.fig_41Method
Reproduce Fig 7.41. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-30: stabilization policies introduced in the year 2000.
The combination of adaptive technological and social policies of the previous run are not introduced until the year 2000. The continuation of
growth for an additional 25 years further erodes the carrying capacity of
World3; therefore, the policies that led to equilibrium 25 years earlier are
no longer effective.
source
WorldDynamics.World3.fig_5Method
Reproduce Fig 7.5. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-4: nonrenewable resource sector behavior, 1900-1970.
The rate of usage of nonrenewable resources NRUR grows exponentially
at 4 percent per year over the historical period. This continuous increase is caused by the growth in both population POP and resource usage per
capita PCRUM. Per capita resource usage rises as a result of industrial
development. The increase in resource usage occurs at no additional increase
in unit costs (see FCAOR in graph), in accordance with historical trends.
In 1970, over 90 percent of the initial supply of nonrenewable resources
remains to be used.
source
WorldDynamics.World3.fig_6Method
Reproduce Fig 7.6. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-5: persistent pollution sector behavior, 1900-1970.
The rate of generation of persistent pollutants PPGR increases exponentially as its two components, persistent pollutants generated from industrial output PPGIO and persistent pollutants generated from agricultural output PPG AO, rise over the 70-year period. After a 20-year delay, the persistent pollutant appearance rate PPAPR also rises, causing the index of persistent pollutants PPOLX to rise and eventually pass through its normalized value of 1.0 in 1970.
source
WorldDynamics.World3.fig_7Method
Reproduce Fig 7.7. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-6A: World3 reference run.
This is the World3 reference run, to be compared with the sensitivity and
policy tests that follow. Both population POP and industrial output per
capita IOPC grow beyond sustainable levels and subsequently decline. The
cause of their decline is traceable to the depletion of nonrenewable resources. Runs 7-6B and 7-6C illustrate the mechanisms that force population POP and industrial output per capita IOPC to decline.
source
WorldDynamics.World3.fig_8Method
Reproduce Fig 7.8. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-6B: capital sector variables from the reference run.
This and the following run depict the mechanisms that forced population POP
and industrial output per capita IOPC to decline in the preceding reference
run (Figure 7.7). As resources are depleted, a larger fraction of capital must be allocated to obtaining resources FCAOR after the year 2000. FCAOR
rises quite steeply because of the high rate of growth of the nonrenewable
resource usage rate. The increase in FCAOR reduces the amount of capital allocated to producing industrial output so that both industrial output
10 and industrial output per capita 10PC decrease after the year 2015.
The lower industrial output 10 causes a reduction in total agricultural
investment TAI and therefore in the amount of agricultural inputs per
hectare AIPH allocated to producing food.
source
WorldDynamics.World3.fig_9Method
Reproduce Fig 7.9. The original figure is presented in Chapter 7 of [DGFW](https://archive.org/details/dynamicsofgrowth0000unse).

Caption: Run 7-6C: agriculture sector variables from the reference run.
As the level of agricultural inputs per hectare AIPH decreases after the
year 2015 (Run 7-6B), land yield LY begins to fall. The resulting drop in
food production causes food per capita FPC to decline after 2015. The
lower food per capita FPC in turn reduces the lifetime multiplier from food
LMF, which eventually raises the death rate and stops population growth.
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Reproducing World3-91 figures

World3-91 system

WorldDynamics.World3_91.fig_scenario1aMethod

Reproduce the first subfigure of Scenario 1 from Chapter 4, page 133, in BTL.

Caption: The "Standard Run" from The Limits to Growth The world society proceeds along its historical path as long as possible without major policy change. Population and industry output grow until a combination of environmental and natural resource constraints eliminate the capacity of the capital sector to sustain investment. Industrial capital begins to depreciate faster than the new investment can rebuild it. As it falls, food and health services also fall, decreasing life expectancy and raising the death rate.

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WorldDynamics.World3_91.fig_scenario1bMethod

Reproduce the second subfigure of Scenario 1 from Chapter 4, page 133, in BTL.

Caption: The "Standard Run" from The Limits to Growth The world society proceeds along its historical path as long as possible without major policy change. Population and industry output grow until a combination of environmental and natural resource constraints eliminate the capacity of the capital sector to sustain investment. Industrial capital begins to depreciate faster than the new investment can rebuild it. As it falls, food and health services also fall, decreasing life expectancy and raising the death rate.

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WorldDynamics.World3_91.fig_scenario2aMethod

Reproduce the first subfigure of Scenario 2 from Chapter 4, page 135, in BTL.

Caption: Doubled Resources Are Added to Scenario 1 If we double the natural resource endowment we assumed in Scenario 1, industry can grow 20 years longer. Population rises to more than 9 billion in 2040. These increased levels generate much more pollution, which reduces land yield and forces much greater investment in agriculture. Eventually declining food raises the population death rate.

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WorldDynamics.World3_91.fig_scenario2bMethod

Reproduce the second subfigure of Scenario 2 from Chapter 4, page 135, in BTL.

Caption: Doubled Resources Are Added to Scenario 1 If we double the natural resource endowment we assumed in Scenario 1, industry can grow 20 years longer. Population rises to more than 9 billion in 2040. These increased levels generate much more pollution, which reduces land yield and forces much greater investment in agriculture. Eventually declining food raises the population death rate.

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Reproducing World3-03 figures

World3-03 system

WorldDynamics.World3_03.fig_scenario1aMethod

Reproduce the first subfigure of Scenario 1 from Chapter 4, page 169, in LtG30y.

Caption: Scenario 1: A Reference Point The world society proceeds in a traditional manner without any major deviation from the policies pursued during most of the twentieth century. Population and production increase until growth is halted by increasingly inaccessible nonrenewable resources. Ever more investment is required to maintain resource flows. Finally, lack of investment funds in the other sectors of the economy leads to declining output of both industrial goods and services. As they fall, food and health services are reduced, decreasing life expectancy and raising average death rates.

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WorldDynamics.World3_03.fig_scenario1bMethod

Reproduce the second subfigure of Scenario 1 from Chapter 4, page 169, in LtG30y.

Caption: Scenario 1: A Reference Point The world society proceeds in a traditional manner without any major deviation from the policies pursued during most of the twentieth century. Population and production increase until growth is halted by increasingly inaccessible nonrenewable resources. Ever more investment is required to maintain resource flows. Finally, lack of investment funds in the other sectors of the economy leads to declining output of both industrial goods and services. As they fall, food and health services are reduced, decreasing life expectancy and raising average death rates.

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WorldDynamics.World3_03.fig_scenario1cMethod

Reproduce the third subfigure of Scenario 1 from Chapter 4, page 169, in LtG30y.

Caption: Scenario 1: A Reference Point The world society proceeds in a traditional manner without any major deviation from the policies pursued during most of the twentieth century. Population and production increase until growth is halted by increasingly inaccessible nonrenewable resources. Ever more investment is required to maintain resource flows. Finally, lack of investment funds in the other sectors of the economy leads to declining output of both industrial goods and services. As they fall, food and health services are reduced, decreasing life expectancy and raising average death rates.

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