more holistic approach, from the beginning, might have achieved considerably more at considerably less cost.
In fact, there is a tendency for suboptimal choices to get "locked in" by widespread adoption. Large investments in so-called clean coal technology would surely extend the use of coal as a fuel—an eventuality highly desired by the energy establishment—but would also guarantee that larger cumulative quantities of sulfur, fly ash (with associated toxic heavy metals), and carbon dioxide would be produced. The adoption of catalytic converters for automotive engine exhaust is another case in point. This technology is surely not the final answer, since it is not effective in older vehicles. Yet it has deferred the day when internal combustion engines will eventually be replaced by some inherently cleaner automotive propulsion technology. By the time that day comes, the world's automotive fleet will be two or three times bigger than it might have been otherwise, and the cost of substitution will be enormously greater.
The implication of all these points for policymakers, of course, is that the traditional governmental division of responsibility into a large number of independent bureaucratic fiefdoms is dangerously faulty.8 Yet the way out of this organizational impasse is far from clear. Top-down central planning has failed miserably and is unlikely to be tried again soon. On the other hand, pure "market" solutions to environmental problems are limited in cases where there is no convenient mechanism for valuation of environmental resource assets (such as beautiful scenery) or functions (such as the ultraviolet radiation protection afforded by the stratospheric ozone layer). This is primarily a problem of indivisibility. Indivisibility means that there is no possibility of subdividing the attribute into "parcels" suitable for physical exchange. In some cases this problem can be finessed by creating exchangeable "rights" or "permits," but the creation of a market for such instruments depends on other factors, including the existence of an effective mechanism for allocating such rights, limiting their number, and preventing poaching or illicit use of the resource.
Needless to say, the policy problems have economic and sociopolitical ramifications well beyond the scope of this paper. However, as the Chinese proverb has it, the longest journey begins with a single step. Developing industrial metabolism as an analytic tool certainly represents one critical step in understanding industrial ecology systems and effecting change toward sustainability.
This analogy between firms and organisms can be carried further, resulting in the notion of "industrial ecology." Just as an ecosystem is a balanced, interdependent quasi-stable community of organisms living together, so its industrial analogue may be described as a balanced, quasi-stable collection of interdependent firms belonging to the same economy. The interactions be