Revised 20 August 2021


  • In 1970, Professor Jay Forrester of MIT presented a global computer model to the Club of Rome which took into account over 100 factors including population, agricultural production, natural resources, industrial production, and pollution. The results of this study were published in the book The Limits to Growth published in 1972.
  • The Limits to Growth made the following four points: National policies that existed prior to and in 1972 promoted exponential growth in population and material consumption; There are limits to growth because the Earth is finite; exponential growth on a finite planet will inevitably stop either voluntarily or due to mounting global pressures; the sooner we act to slow down exponential growth and stop growth in population and material consumption, the more possibilities will be available for future generations.
  • The minimum requirements for global equilibrium, or steady state, were defined as being: The capital plant and the population are constant in size. The birth rate equals the death rate and the capital investment rate equals the depreciation rate; All input and output rates - births, deaths, investment, and depreciation - are kept to a minimum.
  • The above minimum requirements for steady state in a human ecosystem are equivalent to the conditions for climax in other ecosystems.
  • The Limits to Growth was widely criticised. The main finding of The Limits to Growth - 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."
  • A second report to The Club of Rome, Humankind at the Turning Point headed by Mihajlo Mesarovic and Edward Pestel also used a world dynamics model which used about 100,000 relationships as compared to a few hundred in previous world models. The main conclusion of the report was that 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. 
  • Limits to Growth (1972) was updated in 1992 with a further update in 2004. 
  • The Limits to Growth (1972) was interpreted by some critics as being a prediction of gloom. This is incorrect. Limits to Growth (1972) was not about a preordained future, but instead was about choice. Limits to Growth (1972) raised questions such as: What will happen if growth in the world’s population continues unchecked; What will be the environmental consequences if economic growth continues at its current pace; What can be done to ensure a human economy that provides sufficiently for all and that also fits within the physical limits of the Earth.
  • In 1991 the Club of Rome team had a re-look at prevailing environmental data and realised that despite the world's improved technologies, humanity had already overshot the limits of Earth’s support capacity. Resource and pollution flows had grown beyond their sustainable limits. This conclusion was based on independent research cited in the Club of Rome 1992 edition, Beyond the Limits: Global Collapse or a Sustainable Future, referred to here onwards as Limits to Growth (1992).  
  • Limits to growth (1992) concluded the following: Without significant reductions in material and energy flows, there will be in the coming decades an uncontrolled decline in per capita food output, energy use, and industrial production; this decline is not inevitable; a sustainable society is still technically and economically possible. 
  • In anticipation of further claims of predictions of gloom, Limits to Growth (1992) added the following clarification to the above conclusions: “These conclusions constitute a conditional warning, not a dire prediction. They offer a living choice, not a death sentence. The choice isn’t necessarily a gloomy one. It does not mean that the poor must be frozen in their poverty or that the rich must become poor. It could actually mean achieving at last the goals that humanity has been pursuing in continuous attempts to maintain physical growth.” (
  • In 1997, Mathis Wackernagel et al. measured the ecological impact of 52 large countries inhabited by 80% of the world population and compared it to Earth’s carrying capacity. Wackernagel et al. concluded that the impact of population and material consumption, or humanity’s ecological footprint, exceeded the Earth’s carrying capacity by 20%. By 1997, the ecological footprint exceeded the Earth’s carrying capacity by 33%. 
  • Limits to Growth (2004) concluded: “We are much more pessimistic about the global future than we were in 1972. Humanity has largely squandered the past 30 years in futile debates and well-intentioned, but half-hearted, responses to the global ecological challenge.” 
  • Limits to Growth (2004) stressed that “resulting damage and suffering can be greatly reduced through wise policy”, and once again clarified that: “We do not write this book in order to publish a forecast about what will actually happen in the twenty-first century. We are not predicting that a particular future will take place. We are simply presenting a range of alternative scenarios: literally, 10 different pictures of how the twenty-first century may evolve. We do this to encourage your learning, reflection, and personal choice”.
  • The three editions of The Limits to Growth reflect a changing understanding of climate change. The 1972 publication showed the C02 curve going up, but the CO2 curve was included primarily to illustrate an example of persistent pollution. There was limited understanding and concern about climate change in 1972. 
  • By 2021, climate change has become a major over-riding global environmental pressure. Notwithstanding the current global focus on mitigating climate change, climate change is but one of several symptoms caused by population growth and growth in material consumption