|Models||Meadows||Brocker I 550
Models/Simulation/World3/Growth/Meadows: Meadows used the preparatory work of Jay W. Forrester, who developed the World-2-model at MIT (Forrester 1971 (1)) to develop his model "World3". Meadows: focused on five macroeconomic variables: population, food production, industrial production, raw material stocks and environmental pollution (2). All five variables are characterized by exponential growth.
Problem: Even food production can only be increased linearly.
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World3 model: is constructed from 4 steps: 1. The interaction of the 5 basic variables is described in feedback control loops. This can be positive (increasing) or negative.
2. These interactions are defined, resulting in 99 variables that are linked in more than one hundred basically similar causal chains. (3)
3. This data was calculated on the computer for the 200 years between 1900 and 2100. The inputs were varied several times to observe the behavior of the system.
4. Measures proposed at that time were introduced into the system on a trial basis. (4)
Results: A. The curves of the first seventy years to the present were identical in all runs, then they diverged and documented how the model reacted to different of the fed-in quantified assumptions. The system behaviour clearly tends to exceed the limits of growth and then collapses," wrote the authors, with the collapse taking place "as a result of depletion of raw material stocks" (5).
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B: The various scenarios (assumptions about population growth, food resources, technologies, etc.) showed climate change to be the most pressing global environmental problem. All runs with variants ended in system crashes This would ultimately lead to a decline in population and industrial capacity (6)
VsMeadows: the results were to be expected since the facility ((s) of simulation) was chosen such that exponentially growing factors (population and industrial production) were interacting with limited factors (food, raw material stocks,
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absorption capacity of pollutants). Under these assumptions, the model world inevitably had to collapse sooner or later. The result was ultimately included in the question.
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VsMeadows: his model ignored the price mechanism. This would ensure that scarce goods would be replaced by abundant goods. VsMeadows: his database is too narrow for far-reaching statements.
VsMeadows: there is a lack of regional differentiation, which leads to a hasty globalisation of problems. Ultimately, this will depoliticize the problem.
VsMeadows: recent criticism: the predicted shortage of resources and food has failed to materialize.
1. J.W. Forrester, Word Dynamics, 1971
2. Vgl. Donella H. Meadows/Dennis L. Meadows/Jørgen Randers/William W. Behrens III, The Limits to Growth. A Report for the Club of Rome’s Project on the Predicament of Mankind, New York 1972. Dt.: Dennis Meadows/Donella Meadows/Erich Zahn/Peter Milling, Die Grenzen des Wachstums. Bericht des Club of Rome zur Lage der Menschheit, Stuttgart 1972, p. 15
3. Ibid. p. 108, Diagramm des Weltmodells: p. 88-91.
4. Ibid. p. 76-77.
5. Ibid. p. 111.
6. Ibid. p. 17.
Patrick Kupper, „Dennis Meadows u. a., Die Grenzen des Wachstums“ in: Manfred Brocker (Hg.) Geschichte des politischen Denkens. Das 20. Jahrhundert. Frankfurt/M. 2018
Dennis L. Meadows
Dynamics of Growth in a Finite World Cambridge 1973
Geschichte des politischen Denkens. Das 20. Jahrhundert Frankfurt/M. 2018