A physical view of sustainability

Bruce Hannon*, Matthias Ruth, Evan Delucia

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We assume that natural ecological communities tend to maximize the amount of stored biomass on a given area, thereby creating the highest sustainable rate of entropy formation possible from that area. We take this climax condition to define sustainability. Human intervention, through agriculture, reduced the ecosystem in given areas to a juvenile state, a state which seems to produce entropy at a lower rate than that of the natural climax condition. The gap in entropy production rates between the natural and the agricultural system would eventually be overcome by the direct and indirect use of fossil fuels. These fossil fuels are consumed much faster than they are being formed and, therefore, a social structure based on their extensive use cannot be sustainable. What type of social structure does meet our definition of sustainability? That is, what style and size of social activity will generate entropy at a rate no greater than that of the climax ecosystem in a particular area? During the last two decades, studies of economic activities and their environmental repercussions were limited to the possible costs and benefits of pollution control and to the economically optimal extraction rates of mineral resources. The intrusion of human activities into the environment became increasingly apparent through the depletion of natural resource stocks and decreasing environmental quality. In the 1990s, sustainability of the socio-economic system within the global ecosystem has become the pressing issue. Although research is increasingly concerned with the question of sustainability, a definition based on physically measurable evidence is missing. Such a definition is proposed in this paper and an example application is given for a particular area.

Original languageEnglish
Pages (from-to)253-268
Number of pages16
JournalEcological Economics
Issue number3
Publication statusPublished - 1 Apr 2002

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