Revised 24 May 2019

In 1973, a year after The Limits to Growth was published, thirteen essayists associated with the Science Policy Research Unit of the University of Sussex published the book Thinking about the Future: A Critique of The Limits to Growth. This book represented a severe criticism levelled against the findings of Limits to Growth. The team was co-ordinated by Marie Jahoda, Professor of Social Psychology at the University of Sussex. The main criticisms of the Sussex team were as follows:


    1. There is insufficient data available to construct a satisfactory world model.
    2. The Limits to Growth team concentrated on physical limits to growth and omitted to take into account changes in values. 
    3. That there are strong simplistic technocratic tendencies inherent in Forrester’s approach. (Cole et al., 1973)

The general nature of criticism was on points of methodology which the Limits to Growth team itself had pointed out. Some criticisms were on points of accuracy. The general conclusion of the Sussex team was that forecasts of the world's future are very sensitive to a few key assumptions and the Sussex team suggested that the assumptions made by the Limits to Growth team might be unduly pessimistic. The Sussex team concluded:

"The major weakness of the world dynamics models is that they illustrate the pessimistic consequences of exponential growth in a finite world without taking account of politics, social structure, and human needs and wants. The introduction of an extra variable – man - into thinking about the world and its future may entirely change the structure of the debate which these models have so far limited to physical properties." (Cole et al., 1973, p209)

The main finding of the Limits to Growth team - that unless population and capital growth are constrained, further growth would eventually lead to collapse - was unsuccessfully challenged. As Kenneth Boulding stated in the United States Congress House in 1973, “Anyone who believes that exponential growth can go on forever in a finite world is either a madman or an economist." 

1976 heralded in the publication of the second report to The Club of Rome - Humankind at the Turning Point. Mihajlo Mesarovic and Edward Pestel headed the research team which also used a world dynamics model with the following major structural characteristics:

    1. "The world system is represented in terms of interdependent subsystems, termed regions. This is essential to account for the variety of political, economic, and cultural patterns prevailing within the world system.
    2. The regional development systems are represented in terms of a complete set of descriptions of all essential processes which determine their evolutionary, i.e.; physical, ecological, technological, economic, social, etc. 
    3. Account is taken of the apparent capability possessed by the world development system to adapt and change.” (Mesarovic & Pestel, 1976, p36)

The computer model used about 100,000 relationships as compared to a few hundred in other world models. The following conclusions were made:

    1. "A world consciousness must be developed through which every individual realises his role as a member of the world community... 
    2. A new ethic in the use of material resources must be developed which will result in a style of life compatible with the oncoming age of scarcity. This will require a new technology of production based on minimal use of resources and longevity of products rather than production processes based on maximal throughput. 
    3. An attitude toward nature must be developed based on harmony rather than conquest. 
    4. If the human species is to survive, humankind must develop a sense of identification with future generations, and be ready to trade benefits to the next generations for the benefits to himself. If each generation aims at maximum good for itself, Homo Sapiens is as good as doomed." (Mesarovic & Pestel, 1976, p147)