The Meaning of Sustainability

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Background on Sustainabilty

In the 1960s and 1970s, it became apparent to many thoughtful individuals that global populations, rates of resource use and environmental degradation were all increasing so rapidly that these increases would soon encounter the limits imposed by the finite productivity of the global ecosphere and the geological availability of mineral and fossil fuel resources.

Perhaps most prominent among the publications that introduced the reality of limits in hard quantitative terms was the book Limits to Growth1 which, in 1972, reported the results of computer simulations of the global economy that were carried out by a systems analysis group at MIT. The simulation recorded five parameters for the global economy (population, agricultural production, natural resources, industrial production and pollution) for the period of time from 1900 to 1970 and then projected the computer-generated values of these parameters for the period from 1970 to 2100. For a wide range of input assumptions, the projections predicted a major collapse of world population in the mid-twenty first century. The computed results seemed to show that sustainability of life as we know it may not be an option.

Limits to Growth evoked admiration from scientists and environmentalists who were comfortable with quantitative analysis. The study evoked consternation from less quantitative types who tend not to believe in limits. Limits to Growth precipitated immediate and urgent rebuttals from the global economic community which proclaimed that human ingenuity can overcome all shortages so that, in effect, there are no limits.2, 3 The book Limits to Growth got people thinking about sustainability.

We must be clear on the meaning of sustainability before we make any more use of the term. A very commonly used definition of sustainability is implied in the following definition of sustainable development which is found in the report of the Brundtland Commission of the United Nations4:

Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

We must note two important things. First, “future generations” (plural) implies “for a very long time,” where long means long compared to a human lifetime.” Second, the arithmetic of steady growth shows that steady growth of populations or of rates of resource consumption for modest periods of time leads to sizes of these quantities that become so large as to be impossible. The combination of these two observations leads us to the First Law of Sustainability5:

Population growth and/or growth in the rates of consumption of resources cannot be sustained.

The First Law is based on arithmetic so it is absolute. Science is not democratic, so the First Law of Sustainability is not debatable; it can not be modified or repealed by professional societies, by congresses or by parliaments. The First Law implies that the term “Sustainable Growth” is an oxymoron. This is true when this term is used by an untutored person on the street, by an economics professor, or by the President of the United States.6

Albert Bartlett

Albert A. Bartlett (1923-2013) was Professor Emeritus in Nuclear Physics at University of Colorado at Boulder.Dr. Bartlett received a BA degree from Colgate University and MA and PhD degrees in Nuclear Physics from Harvard University in 1948 and 1951, respectively. He was a faculty member at the University of Colorado since 1950. He was President of the American Association of Physics Teachers in 1978. In 1981 he received the Association's Robert A. Millikan Award for his outstanding scholarly contributions to physics education.
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