Communication and Education, Sunseed News

Limits to Growth (Club of Rome, 1972) and prediction of CO2 emissions based on Limits to Growth‘s scenario

July 9, 2013

by Magued Mohamed.

On Thursday 4th of July 2013, a seminar entitled Limits to Growth was held in Sunseed. The moderator presented the contents and the predictions of a scientific book entitled “limits to Growth” which was published in 1972 by the Club of Rome, whose aim is to discuss short-term thinking in international affairs regarding unlimited resource consumption in an increasingly interdependent world. Then he compared its predictions to a scientific paper entitled “A comparison of the Limits to Growth with thirty years of reality” by Graham Turner which was published in 2008. Finally he discussed his prediction of CO2 emissions’ curve based on the book‘s Standard Run scenario of the pollution curve. In 1798, an English Anglican priest published an anonymous essay on the principle of population which sparked a massive interests and controversies. In contrary to the optimism of the Zeitgeist, the outcome of the book was pessimistic. He concluded that people will die due to famine and diseases and emphasized “Doomsday Scenario”. What made this essay influential is not the religious tone in it but the mathematical and scientific arguments on which it was based. The main argument was that people grow exponentially whilst resources grow linearly. This essay inspired Charles Darwin, Karl Marx, Charles Dickens and others. However, the data in the twentieth century did not tally with these predictions as world population grew, agricultural yield increased due to green revolutions and disease were taken care of by the advancement of medicine. In an attempt to reexamine these predictions, Club of Rome commissioned a group of scientists from MIT led by Dr. Donella Meadows to investigate the matter. The commission used a simulation computer model called Wordl3. Five variables were examined in the original model, on the assumptions that world population, industrialization, pollution, food production and resource depletion have an exponential tendency to grow. On the other hand, the ability of technology to increase the availability of resources grows only linearly. The main purpose of The Limits to Growth was not to make specific predictions with numbers and values, but rather to explore how exponential growth interacts with finite resources and to show their tendencies. Data from 1900 to 1970 were fed into World3. Three scenarios were generated: Standard Run; Comprehensive Technology and Stabilized Run.

Fig 1 Fig 1: Standard Run. Standard Run (the actual business-as-usual situation) has parameters reflecting physical, economic and social relationships where these parameters were maintained in the World3 model at values consistent with the period 1900-1970.

Fig 2 Fig 2: Comprehensive Technology. Comprehensive Technology (the optimistic scenario) which attempts to solve sustainability issues with a broad range of purely technological solutions; assuming resources are effectively unlimited; 75% of materials are recycled; pollution generation is reduced to 25% of its 1970 value; agricultural land yields are doubled and birth control is available world-wide.

fig 3

Fig 3: Stabilized Run with stabilized population and capital. Stabilized Run (the rational scenario) has stable population and capital, with the forces tending to increase or decrease them in a carefully controlled balance. In order to do so, the capital and the population are constant in size with constant rate and that all rates are kept to a minimum. This target can be achieved by either enforcing negative feedback such as the pollution; the depletion of resources or the famine or by weakening positive feedback such as reducing birth rate or reducing capital growth. The authors concluded that if the current growth trends continue unchanged the limits to growth will be reached sometime within the next one hundred years (2072); the most probable result will be a sudden and uncontrollable decline in both population and industrial capacity and recommended altering these trends to establish a sustainable conditions of ecological and economic stability through a state of global equilibrium; the sooner the better. The concept of “sustainable development” instead of economical growth is a direct result of this essay. A comparison of the limits to growth with 30 years of reality by Graham Turner was published in June 2008. The author stated that the recommendations of Limits to Growth to reach a stabilized world were not taken. The analysis showed that observed data after 30 years compare favorably with Standard Run scenario and indicates the particular importance of understanding and controlling global pollution. Prediction of CO2 emissions from the year 2000 to 2100 based on the book‘s Standard Run scenario of the pollution was presented.

Fig 4

Fig 4: estimated CO2 emissions Gtons/Year.

It is predicted that CO2 will increase until the year 2035 reaching (20.16Gtons) then decrease with different rates until it reaches (0.8064Gtons) by 2100.

Fig 5

Fig 5: estimated CO2 emissions with 15% error.

When a 15% margin of error is introduced to the model, CO2 will increase until the year 2035 reaching (17.136 Gtons) then decrease with different rates until it reaches (0.68544Gtons) by 2100. The following table reflects the measured data by US Energy Information Administration and predicted values.

Year estimated data without error margin estimated data with 15% error margin measured data
2000 5.76 4.896 6.586
2001 6.12864 5.209344 6.612
2002 6.49728 5.522688 6.797
2003 6.86592 5.836032 7.087
2004 7.23456 6.149376 7.400
2005 7.6032 6.46272 7.707
2006 7.98336 6.785856 7.917
2007 8.36352 7.108992 8.109
2008 8.74368 7.432128 8.251
2009 9.12384 7.755264 8.246
2010 9.504 8.0784 8.591
2011 9.792 8.3232 8.885
2012 10.08 8.568 9.709
References: by Magued Mohamed . On Thursday 4th of July 2013, a seminar entitled Limits to Growth was held in Sunseed. The moderator presented the contents and the predictions of a scientific book entitled “limits to Growth” which was published in 1972 by the Club of Rome, whose aim is to discuss short-term thinking in international affairs regarding unlimited resource consumption in an increasingly interdependent world. Then he compared its predictions to a scientific paper entitled “A comparison of the Limits to Growth with thirty years of reality” by Graham Turner which was published in 2008. Finally he discussed his prediction of CO2 emissions’ curve based on the book‘s Standard Run scenario of the pollution curve. In 1798, an English Anglican priest published an anonymous essay on the principle of population which sparked a massive interests and controversies. In contrary to the optimism of the Zeitgeist, the outcome of the book was pessimistic. He concluded that people will die due to famine and diseases and emphasized “Doomsday Scenario”. What made this essay influential is not the religious tone in it but the mathematical and scientific arguments on which it was based. The main argument was that people grow exponentially whilst resources grow linearly. This essay inspired Charles Darwin, Karl Marx, Charles Dickens and others. However, the data in the twentieth century did not tally with these predictions as world population grew, agricultural yield increased due to green revolutions and disease were taken care of by the advancement of medicine. In an attempt to reexamine these predictions, Club of Rome commissioned a group of scientists from MIT led by Dr. Donella Meadows to investigate the matter. The commission used a simulation computer model called Wordl3. Five variables were examined in the original model, on the assumptions that world population, industrialization, pollution, food production and resource depletion have an exponential tendency to grow. On the other hand, the ability of technology to increase the availability of resources grows only linearly. The main purpose of The Limits to Growth was not to make specific predictions with numbers and values, but rather to explore how exponential growth interacts with finite resources and to show their tendencies. Data from 1900 to 1970 were fed into World3. Three scenarios were generated: Standard Run; Comprehensive Technology and Stabilized Run. Fig 1 Fig 1: Standard Run. Standard Run (the actual business-as-usual situation) has parameters reflecting physical, economic and social relationships where these parameters were maintained in the World3 model at values consistent with the period 1900-1970. Fig 2 Fig 2: Comprehensive Technology. Comprehensive Technology (the optimistic scenario) which attempts to solve sustainability issues with a broad range of purely technological solutions; assuming resources are effectively unlimited; 75% of materials are recycled; pollution generation is reduced to 25% of its 1970 value; agricultural land yields are doubled and birth control is available world-wide. fig 3 Fig 3: Stabilized Run with stabilized population and capital. Stabilized Run (the rational scenario) has stable population and capital, with the forces tending to increase or decrease them in a carefully controlled balance. In order to do so, the capital and the population are constant in size with constant rate and that all rates are kept to a minimum. This target can be achieved by either enforcing negative feedback such as the pollution; the depletion of resources or the famine or by weakening positive feedback such as reducing birth rate or reducing capital growth. The authors concluded that if the current growth trends continue unchanged the limits to growth will be reached sometime within the next one hundred years (2072); the most probable result will be a sudden and uncontrollable decline in both population and industrial capacity and recommended altering these trends to establish a sustainable conditions of ecological and economic stability through a state of global equilibrium; the sooner the better. The concept of “sustainable development” instead of economical growth is a direct result of this essay. A comparison of the limits to growth with 30 years of reality by Graham Turner was published in June 2008. The author stated that the recommendations of Limits to Growth to reach a stabilized world were not taken. The analysis showed that observed data after 30 years compare favorably with Standard Run scenario and indicates the particular importance of understanding and controlling global pollution. Prediction of CO2 emissions from the year 2000 to 2100 based on the book‘s Standard Run scenario of the pollution was presented. Fig 4 Fig 4: estimated CO2 emissions Gtons/Year. It is predicted that CO2 will increase until the year 2035 reaching (20.16Gtons) then decrease with different rates until it reaches (0.8064Gtons) by 2100. Fig 5 Fig 5: estimated CO2 emissions with 15% error.