Limits to Growth Model

If the present growth trends in world population, industrialization, pollution, food production, and resource depletion continue unchanged, the limits to growth on this planet will be reached sometime within the next one hundred years. The most probable result will be a rather sudden and uncontrollable decline in both population and industrial capacity.

Historical Background

Many academicians approached world political leaders and expressed the future threats that would arise due to the implications of an increasing population, which were initially neglected. A group of international economists, scientists, philosophers, and geographers founded The Club of Rome in 1968, and expressed the first official concern in this regard, which gained attention from many governments.

In 1972, Prof. Jay. Forrester of the Massachusetts Institute of Technology developed a special model on "Limits to Growth", published by the Club of Rome. This model addressed how the equilibrium between a growing population and finite, non-renewable resources get disturbed. Forrester’s model on "Limits to Growth" was carried forward by his colleagues Dennis Meadows and Donnella Meadows, with the assistance of Jergen Randers and William W. Behrens.

Forrester Meadows Model

A dynamic, systematic approach was used in this special model that projected the events likely to happen if the current economic, demographic, and resource utilization trends are traced. This model analyzed the interaction between the following five major variables.

• Population

• Pollution

• Natural resources

• Industrial output per capita

• Food per capita

Assumptions

The most important assumptions in this model can be summarized as follows −

• The non-renewable resources are finite in stock and exploitable in nature.

• The land used to grow food (arable land) is finite.

• The capacity of the environment to absorb pollutants is limited.

• The productivity of arable land is finite.

• There is an expansion of the population.

• The pollution associated with industrial output exists as long as the resources are available.

• The technological process of birth control, pollution control, and recycling of resources can be developed.

Projections of the Model

With the help of the absorbed data on population, pollution, natural resources, industrial output, and food per capita between 1900 and 1970, the model attempts to project changing trends and their consequences up to the year 2100. Dramatic results were drawn from feeding those data into computer simulations. Hence, the "Limits to Growth" model is a projection, not a mere prediction. Even a minor change or impact in any of the factors significantly pushes problems to others, makes them highly interdependent.

Different scenarios were projected in the model, giving at least seven different permutations. Each of such permutation assumes alternations to growth in different combinations of the major factors. Among the various relationships, there are "feedback loops" that register the effects of changes in one variable on another.

First Run

It is a "standard run", that exhibits exponential growth in all the variables, resulting in overshoot and collapse. Due to the high level of industrialization, wide-scale exploitation of the resources takes place. This creates a need for the search for new resources, requiring more capital. Due to this, the agricultural sector lacks investment and food scarcity occurs. Growth halts in all areas and collapses in 2100.

Second Run

Technological development is introduced to address the effects of resource depletion indirectly influencing population growth. Pollutants from industries outnumber the environment's ability to absorb them. Increasing pollution and population lead to food scarcity, thereby increasing the death rate. This makes the collapse of the variables in 2100 inevitable.

Third Run

To control the pollution factor, the process of recycling has been initiated. But the recycling process itself causes a considerable amount of pollution. Increased pollution levels seriously affect the pattern of agriculture. This results in a lower yield of agricultural resources, failing to completely satisfy the population. In 2100, all sectors of growth collapsed due to food insecurity.

Fourth Run

Nuclear power, along with recycling, seemed to be the best-known solution to control pollution. High levels of population and extensive industrialization caused a shortage of arable land. Consequently, food security collapses and influences all the other variables to disintegrate in 2100.

Fifth Run

To overcome the problems of land exhaustion, high-yield variety crops were introduced. Despite the control measures, the population level increases, which will be a source of collapse in 2100.

Sixth Run

Voluntary birth control measures were provided to control the increasing population. This can only slow down population growth and postpone the food crisis.

Seventh Run

The solution for each run and its consequences are fed into the computer. It is again simulated, which results in the same output as observed in the earlier runs and makes the collapse of all the factors in 2100 inevitable.

Criticism

• It does not account for the infinite possibilities of human innovation.

• Obsolete computer technology may be erroneous in nature.

• The distinction among countries was not considered.

• The model is more pessimistic in the report.

• It failed to reason out the collapse in 2100.

• A minor miscalculation in the initial stage became exponentially bigger.

Conclusion

'Limits to Growth' model served as the pioneer of computer simulation models. We recognize that world equilibrium can become a reality only if the lot of the so-called developing countries is substantially improved, both in absolute terms and relative to the economically developed nations, and we affirm that this improvement can be achieved only through a global strategy. The closer we come to the material limits of the planet, the more difficult this problem will be to tackle.

Frequently Asked Questions

What does the “Limits to Growth” model exactly explains?

“Limits to growth” is an environmentalist vision, that represents the growing pressure on the finite availability of non-renewable resources due to the expanding population. This model discusses the interlinkage between economic growth, population expansion and environmental deterioration.

What are the major variables in the Forrester Meadows model?

Following are the major models of Forrester Meadows model −

• Population

• Pollution

• Natural resources

• Industrial output per capita

• Food per capita