World3

The World3 model was a computer simulation of interactions between population, industrial growth, food production and limits in the ecosystems of the Earth. It was originally produced and used by a Club of Rome study that produced the model and the book Limits to Growth. The principal creaters of the model were Donella Meadows, Dennis Meadows, and Jørgen Randers.

The model was documented in the book Dynamics of Growth in a Finite World. It added new features to Jay W. Forrester's World2 model. Since World3 was originally created it has had minor tweaks to get to the World3/91 model used in the book Beyond the Limits and later was tweaked to get the World3/2000 model distributed by the Institute for Policy and Social Science Research.

Model

The model consisted of several interacting parts. Each of these dealt with a different system of the model. The main systems where the food system, dealing with agriculture and food production, the industrial system, the population system, the non-renewable resources system and the pollution system.

Agricultural system

The simplest useful view of this system is that there is land and fertilizer are used for farming, and more of either will produce more food. In the context of the model, since land is finite, and industrial output required to produce fertilizer and other agricultural inputs can not keep up with demand, there will be a food collapse at some point in the future.

Nonrenewable resources system

The nonrenewable resource system starts with the assumption that the total amount of resources available is finite (about 110 times the consumption at 1990s rates for the world3/91 model). These resources can be extracted and then used for various purposes in other systems in the model. An important assumption that was made is that as the nonrenewable resources are extracted, the later resources are increasingly difficult to extract.

External links

• The Institute for Policy and Social Science Research