DOI
N/A

Summary
The analysis of World 3 scenarios turns out to a concern for growing costs of exploiting the globe´s sources and sinks. Those costs emerge from a combination of physical, environmental, and social factors. Eventually they will be high enough that growth in industry can no longer be sustained which is made plausible by looking at global data. The assertion is based on necessary resources divided in two categories, physical necessities for industry and social necessities. Price is the best indicator for the first category, while the second, social factors are considered as difficult to assess and probably impossible to predict. Thus, the assumption is made that the best possible conditions will prevail. The chapter then goes on to discuss resource use from an entropy model where the different conversions in the economic subsystem eventually will lead to a heat loss for the global ecosystem. Resources are then categorized as renewable for which the rate of use cannot be greater than the regeneration, non-renewable where the sustainability rate of use can be no greater than the rate at which they can be substituted for by renewable resources, and finally the pollutants where the rate can be no greater than the pollutant can be recycled, absorbed or rendered harmless. The chapter then turns to a presentation of measures and trends in global data for the main physical necessities.

Relevance for Complex Systems Knowledge
In chapter 3 the discussion focus on possible results of the system dynamics model. The discussion is is open as regards different types of uncertainties, relating to uncertainties in the model and to the availability of data and facts from the real world. Uncertainties regarding positive and negative feedback loops is discussed in relation to climate change. The discussion on possible scenarios include ethical dimensions for decision making based on the overview of scenarios.

Point of Strength
The chapter can serve as a standalone discussion on possible world scenarios and opportunities to act upon them. It can be used to showcase what can be done with system dynamic modelling and it can be used to discuss strengths and weaknesses of the approach.