College of Business Administration

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John R. Ehrenfeld

Industrial Ecology: Paradigm Shift or Normal Science? The American Behavioral Scientist, Oct 2000. Vol. 44, Iss. 2; pg 229, 16 pga

Abstract (Document Summary)

Industrial ecology is an evolving framework for the analysis and design of public policy, corporate strategy, and technological systems and products. Its metaphorical denotation springs from conceptual models characteristic of sustainable or long-lived ecosystems.

Industrial ecology is an evolving framework for the analysis and design ofpublic policy,corporate strategy and technological systems and products. Its metaphorical denotation springs from conceptual models characteristic of sustainable or long-lived ecosystems. Some authors stress the material and energy flows within a system of producers and consumers and aim to build knowledge about these flows that can be used for such design purposes as above. Others see industrial ecology primarily in its more metaphorical sense as providing new normative themes for a possibly sustainable world. Such norms include connectedness, cooperation, and community These particular norms are, more or less, contrary to prevailing elements ofsocial structures in market-based, industrialized nations. The paradigmatic, normative potential of industrial ecology is contrasted with its potential as an emerging "science" of sustainability

EXPANDING ON SUSTAINABLE DEVELOPMENT

Emerging during about the past 10 years, industrial ecology is a new approach to the analysis and design of sustainable political economies (Erkman, 1997). It has attracted the attention of academics, business managers, and policy makers. But it remains today a somewhat fuzzy concept. I will comment on that state of affairs and argue that such fuzziness is positive. Industrial ecology as it exists today has two related but distinctive shapes. One is paradigmatic, normative, and metaphorical. The other is descriptive and analytic. The paradigmatic aspect is critical to those who would argue that sustainability is fundamentally different from the emergent, politically correct notion of sustainable development and that industrial ecology can serve as a new paradigmatic metaphor. The descriptive/analytic character of industrial ecology is holistic and systems oriented. The strength of this side is that it offers models that may transcend the limitations of narrowly bounded knowledge a more robust, holistic system for examining and designing industrial and social networks.

Other papers in this symposium have argued that in the long run, green technology will disappear; that is, everything will become "green" and the current distinction that categorizes environmentally preferable or "sustainable" products and services will slowly fade away. In a technologically sustainable world, it must disappear. However, I do not believe that it will happen easily. In order for routine technological and institutional innovation processes to become so transparent, we need a different way of thinking and of seeing the world.

As preface to an argument that a new social paradigm is needed, examine the four parts of Figure 1. Each is a typical pattern of behavior for a complex system with many interconnected parts providing both positive and negative feedbacks and controlling signals. These curves are simulations generated by a computer using systems dynamics software (Meadows, Meadows, & Randers, 1992).

More or less, all complex system dynamic behavior resembles one of these canonical shapes. The first is the familiar form of exponential growth. This curve appears in systems where no limits to growth exist or where the rate of technical innovation is rapid and any limits can be made to recede as the actors become aware of them. This is the shape predicted by the neoclassic model of political economy. Such a model ignores any limits created by real material scarcity, arguing that scarcity is only an economic artifact and can be made to disappear by the invention of lower priced alternatives. It is arguable that this is true for automobiles or even fossil fuels, but certainly not for stratospheric ozone and species habitats.

The second shape is that of the logistic curve, which shows a gradual, asymptotic approach to a limit. This kind of behavior can be found in complex systems where the actors (controllers)' have clear, accurate signals that tell them how far away they are from the limits and where they also have a relatively precise means of adjusting or slowing down the system to keep within the limits. Passengers in an airplane hope that its automatic landing system will behave in this manner, for example. Economists also speak about soft landings, but not quite in the same sense. In social systems, such steering mechanisms are not available in a practical sense. Society's collective knowledge about the causes of our increasingly complex and large-scale problems has fallen behind that needed to design appropriate controlling mechanisms. In particular, we do not know much about the limits that the world places on our economic activities. Further social controls, particularly in democratic societies, are messy, take a long time to establish, and are often poorly implemented. Even if knowledge were adequate to design, in theory, a logistic-like pattern, it is doubtful that corrective actions would be taken in time to be effective.

Figure 1:

The third curve is characteristic of systems where both the signals and an adequate controlling mechanism are lacking or are of poor quality. Furthermore, as the system approaches and even exceeds the limits, some set of critical elements fails and the system collapses. This is not merely a theoretical pattern. This is the behavior of stratospheric ozone concentration during the past several decades, many of the world's fisheries, and the extinction of species in which case the curve drops irreversibly to zero. In these cases, knowledge is missing (or is ignored), and/or the controlling mechanism is too slow and sluggish to prevent overstressing the critical elements. Even when scientific evidence gathered in the laboratory predicted the potential disappearance of ozone, the creation of a controlling mechanism, the Montreal Protocol, took many years to come to fruition. Global warming concerns may be in the same situation where, even as scientific evidence of system stress mounts, progress on a controlling means is very slow.

The last of the four curves shows behavior where the signals are not perfect and controls exist but are somewhat sluggish, and where the system has sufficient resiliency or robustness to withstand moderate excessive excursions. In this case, the system will oscillate around some limit. This pattern can be found in many natural and human systems.

The point I wish to make in showing these curves is not that I know which best describes the trajectory of the world today. I do not, nor do I believe anyone does. Of course, many make believe that they do. The point I wish to make is that all four look almost the same at the beginning. Foretelling the future by looking at the past is virtually impossible. Human history is far too short, especially when one invokes notions about sustainability far into the future. These curves certainly suggest a strong dose of humility and caution, however. Furthermore, it seems advisable to examine critically the embeddedness of models as to how the world does indeed work in our individual and collective mind-sets. For this article, the starting point for this critical look is the notion of sustainability.

The dominant sense of sustainability is embodied in the so-called Brundtland form of sustainable development (World Council on Environment and Development [WCED], 1987). This definition grew out of the work of the United Nations Commission of Environment and Development and has become the dominant concept of sustainability today. This form of sustainability was endorsed by virtually every government at the Rio Summit in 1992. In this context, sustainable development is a form of development or progress that "meets the needs of the present without compromising the ability of future generations to meet their own needs." What is not stated in this form is that the underlying idea of development takes its shape from current neoclassic economic arguments that equate human welfare to levels of economic output and that assume continuing growth if the market functions properly. It defines scarcity in terms of the limited availability of substitutes at competitive prices without regard to the physical or material reality of factors derived from the natural world. Last, it assumes that as economic scarcity grows, technological innovations will offer more competitively priced substitutes. Some years ago, the Nobel laureate economist Robert Solow (1973) stated that "there is really no reason why we should not think of the productivity of natural resources as increasing more or less exponentially over time" (p. 51 ). The connection to the curve in Figure la is obvious. About the same time, he wrote that "the world can, in effect, get along without natural resources" (Solow, 1974, p. 11).

If this model is correct, then there is no need to be explicitly concerned about the future. Progress will come automatically. Not only is the world to be sustainable for humans far off in time, but such a model promises ever increasing satisfaction. Sustainability in the Brundtland form is tied to a specific model of the world. Many have grave doubts about the accuracy (and appropriateness) of the model's ability to sketch out the future, but my point is not to offer a critique directly about the underlying structures of modernity. In keeping with the notion about humility and explicitly to avoid making any assumption about which of the trajectories global society is on, I offer an entirely different concept for sustainability. Sustainability is a difficult concept. It is difficult because one can never really measure it. It is possible only to know if the world has been sustainable and only by looking backward. To determine if it will be sustainable, one must divine the future by looking at a crystal ball. That is just another metaphor for all the models used by engineers, economists, political scientists, planners, managers, and so on to chart the next strategy for success or for coping with failure. Again, however, one can only know if our practices today are sustainable by waiting until sometime in the future.

In seeking an alternative way to think about sustainability, I would argue that sustainability is a mere possibility that human and other life will flourish on the Earth forever. Flourishing means not only survival but the realization of whatever we humans declare makes life meaningful justice, freedom, and dignity. And as a possibility, it is a guide to actions that will or can achieve its central vision of flourishing day by day by day for time immemorial. Possibilities are empty, created by the declarative power of human language. Possibilities are unconstrained by the limits to action created by following deterministic rules that are the product of past experience and limit action to incremental change. If societies can escape the bounds of the existing mode of living, then all is possible, even that which does not appear available from inside the existing paradigm? Sustainability as possibility is a profoundly and radically different notion of the world than those that dominate our current way of thinking. Sustainability is def finitely not a technological characteristic of the global system such as the term sustainable development would imply. Yet, its realization depends on the nature of the system. It is a future vision from which we can design and then construct our present way of living. Collapsing many current "definitions" of sustainability into a statement ontologically mappable as such a possibility, I suggest the following working definition:

Sustainability is a possible way of living or being in which individuals, firms, governments, and other institutions act responsibly in taking care of the future as if it belonged to them today, in equitably sharing the ecological resources on which the survival of human and other species depends, and in assuring that all who live today and in the future will be able to satisfy their needs and human aspirations.

One key word in the above definition is responsibility, meaning that every action taken would entail a prior assessment of the potential harm of that action to the possibility of sustainability. Responsibility is important as it returns a moral dimension to economics (e.g., Etzioni, 1989) and deepens the role of the actor as much more than a resource maximizer. Robert Heilbroner (1993), a noted American economic historian, has noted that

a second familiar, but no less serious objection [to economic-driven behavior] is that a general subordination of action to market forces demotes progress itself from a consciously intended social aim to an unintended consequence of action, thereby robbing it of moral content. (p. 312)

Again compared with the sustainable development construct, I believe that this way of talking about sustainability is a radical conversation. It is directed at moral actors, not just utility maximizers, and not at some shapeless development process as is the Brundtland form. The Brundtland and related concepts of sustainable development are all inextricably rooted in the present dominant social paradigm (at least in the industrial world) and cannot be radical in the paradigmatic sense that I believe is essential (see Table 1 ). In the language of complex systems, the notion of sustainable development is an emergent property of such a system, whereas the radical definition is focused on the actors within the system.

IS SUSTAINABILITY A NEW PARADIGM OR BUSINESS AS USUAL?

It might be argued that the word paradigm is one of the most abused and overused words in common parlance today. Nonetheless, paradigm in Thomas Kuhn's ( 1962) sense appears useful as a context for exploring both sustainability and the two shapes of industrial ecology. Kuhn's model aims at explaining the process by which one great scientific theory replaces another. Kuhn argues that scientists (and for that matter other actors at all levels of institutional aggregation from individuals to entire societies) carry out their normal, everyday search for truth and satisfaction within a commonly held set of ideas and practices. The set of beliefs, norms, and practices constitutes their paradigm. Another way of stating this is that a paradigm is or contains a set of structures on top of which social action is created, or a vocabulary for describing things, or a story the actors tell about their place in the world. It rests in the background and frames human action individually and in a collective sense. As long as actors can find answers to their questions and solutions to their problems, they will continue to follow the route laid out by the paradigm in their unconscious mind-set and familiar resources and tools. They will do this transparently, routinely, and it is hoped, without serious interruptions.

Interruptions (breakdowns) are inevitable, however. The models that humans use never capture the holistic complexity of the world nor its incessant changes. The "best laid schemes o` mice and men" of Robert Burns do indeed often go awry ("Gang aft a-gley," in the original)' and unintended consequences always lurk in the shadows. The environmental dimension of (un)sustainability today could be considered such an unintended consequence of modernity (Giddens, 1990). No one intended that this should happen. If the actors can cope with these interruptions by digging deeper into the underlying belief system, then they will eventually return to normality. If not, the action comes to a halt and, upon reflection, the hidden foundations may come to the surface. The actors may simply abandon their efforts to cope and turn to other tasks, denying the existence of the problems either implicitly or explicitly.

TABLE 1:

On rare occasions, in Kuhn's model, those at work cannot find the answers they seek and become frustrated or perhaps even anxious if they perceive that their continuing livelihood depends on finding a way out of the current mess. This condition of frustration or anxiety sets the stage for the possibility of paradigmatic transformation (see Figure 2). This figure depicts the process of paradigmatic change rather simplistically but serves to illustrate the point. Those, currently laboring in the top oval, who are committed to coping with some set of worldly problems start to seek new visions and concepts. Furthermore, because of the enhanced consciousness that comes in these interruptions, the world shows up anew rather than remaining hidden behind the opacity of the existing paradigmatic structures (new vision). Again, on rare occasions, some actors seize on what they now see and, through the transformative power of metaphor, construct a new model of the world out of what has now appeared. Once done, these actors can then devise new strategies (new norms) and again turn back to their everyday actions of discovering what the world is all about or, in the sense of sustainability, return to the design of new artifacts and institutional structures that keep the possibility of sustainability alive.

At this point the paradigm shift has occurred, anxiety abates, and the action returns to the normal stage, shown in the bottom of Figure 2. The sequence of actions follows conventional models of intentional behavior. The metaphorical character of the upper stage recedes and the process shifts to the more familiar world of practical action. Metrics and analytic systems become important. This is where the second aspect of industrial ecology emerges as a set of tools and explanatory constructs that permit the actors to proceed without serious, frequent failures. The paradigm-shifting phase is a social process in which new concepts and norms are established in the culture of the institutional world of the actors. Normal practice takes place within those institutions without further social construction. The basis of action now exists in the private worlds of the actors.

Figure 2

With respect to sustainability, then, one needs to ask the question, "In which part of the two-stage process are we?" Are we encountering the persistent breakdowns that signal the end of the utility of one paradigm and call for another? Or, do we simply need better "normal" practices? There are many signs that the basic structures of modernity and of the industrial societies that have come to dominate the globe and continue to grow no longer work so well. Despite great technological advances and increasing levels of affluence (as measured by conventional indicators), persistent problems are showing up in both the natural and the social systems all around the globe. I will not enumerate them here. However, it is important to note that although much attention is paid to natural system problems, like global warming, fisheries collapsing, desertification, and extinction, social indicators tell of failures to move toward the key goals of equity that are also a part even of the Brundtland notion of sustainable development. The gap between rich and poor within and between nations continues to widen. Business grows constantly at the expense of both government and civil society (Korten, 1995).

Given the persistence of the problems, despite the application of more knowledge, better tools, and a clearer ideological sense of the basic fundaments of modernity (see Table 1 ), it is arguable that a new paradigm is called for. It seems that those who are most powerful in creating the future are committed to the present way of doing business.

The reflexive consciousness that signals a shift of paradigms seems missing in the political and economic systems of modern industrial nations. Perhaps it is due simply to the inertia of social systems. Or perhaps it is due to a form of insanity as defined by some as continuing to act in the same manner but expecting the outcome to be different. In such an extreme, the idea of Kuhnian "normal" behavior could be interpreted by observers as socially aberrant behavior (Laing, 1967). Perhaps it is just a matter of conserving power. But what if the powerful are wrong? And what if the radical definition of sustainability does not even exist in the current dominant social paradigm? Where then can one look? In the next section, industrial ecology will be presented as a potential new paradigm out of which societies can construct a sustainable world.

INDUSTRIAL ECOLOGY AS A PARADIGM SHIFT

Let me, then, suggest a different paradigmatic structure for moving toward, and operating within, a sustainable world. As in Table 1, the basic elements of such a paradigm are suggested in Table 2.

Some of these items are simply apposed to their counterparts in Table 1. Others come from a search for examples of sustainability that can serve as the metaphorical basis of a new paradigm. Table 2 is constructed, in part, from the context presented so far but also by thinking about the features of sustainable ecosystems-the source of the ecology metaphor in industrial ecology. Natural ecosystems, in my experience, offer the only worldly example available to humans of long-lived, robust, resilient living systems, the characteristics of which are all features of the radical idea of sustainability as presented earlier. Our own human history offers no similar source for paradigmatically distinct thinking. Three collective features of stable ecosystems seem very important: connectedness, community, and cooperation. Other characteristics such as tightly closed material loops and thermodynamically efficient energy flows offer important themes for technological and institutional design. The underlined elements in Table 2 are directly connected to the ecological metaphor. Other elements relate to the criticality of explicit design and to the ethical sense of sustainability.

Industrial ecology is an emerging concept (Ehrenfeld, 1997; Erkman, 1997) that has already begun to acquire the characteristics of a discipline. I prefer to call it a new field to avoid the sharpness associated with the word discipline. A new journal, the Journal of Industrial Ecology, devoted to both learned and practical articles, was introduced in 1997. In the United States, as in Norway, our National Academy has convened a series of meetings and conferences designed to explore and develop the idea. Many of my colleagues see industrial ecology as an analytic system, but with broader boundaries than those that define other technical areas in science and engineering, much like the discipline of ecology from which the name comes. These academics seek a way to become more holistic and more precise in describing the complexity of the world.

TABLE 2:

I would argue that in the radical sense of sustainability, the analytic or disciplinary form of industrial ecology is not up to the task of coping with unsustainability. I believe that the power of the concept of industrial ecology lies in its normative context and in its potential to shape paradigmatic thinking. It is normative in the sense that the above-mentioned three features of the ecological metaphor-community, connectedness, and cooperation-are characteristics we should strive for in designing our worlds. We ought to become more like an ecological community.

Changing the paradigm to incorporate these three notions is bound to be conflictual and strongly resisted. Such resistance is to be expected as pointed out by Kuhn and nearly all scholars looking at deep social change or even the innovation process for technological systems (Hughes, 1998). In this case, however, this paradigm challenges the current set of ideas head-on. Connectedness runs counter to the positivist, reductionist notions of knowledge and to the central idea of individual libertarianism-the realization of the autonomous self. Community obviously becomes eroded as a result of the latter aspect. Competition is the shibboleth of modern corporate liberalism (Korten, 1995), protected explicitly by the framework of law in the United States and, to a lesser degree, elsewhere in the world. Competition is not inherently normatively bad. Competition exists in natural systems, but in a balance between competition and cooperation. Individual creatures in a given niche compete for scarce resources but never make war on the others in a winner-take-all strategy. Ethologists have found that animals in a niche follow a law of "limited competition." Individuals compete vigorously for a limited food supply, but not beyond the point that the biological success of their community becomes threatened. Restoring such a balance to human communities seems important. The ideas of returns to scale and monopoly are found only in human economies.

The notion of loop closing is not complete without accepting the criticality of detritivores-the scavengers. Scavengers, those at the bottom of the food chain that take the wastes and turn it into something useful are as important as the predators at the top, but not in human society. Scavengers have historically lived in a social niche outside the mainstream of society. They are the untouchables. It appears that this situation must change as it is just as important to have actors who will transform the last bit of what we have called waste into useful materials for society as those who produced the "useful" products in the first place.

Several other characteristics of stable ecosystems also suggest new norms to pursue in thinking about sustainability. One is that these systems are at a steady state, often far from an equilibrium condition. Prigogine (1955) observed several very interesting features about steady state biological systems.` One is that they are in a state of minimum entropy production, that is, the system is functioning with the least degree of dissipation of energy (and materials) thermodynamically possible in a real situation. Furthermore, he noted that as biological systems evolve toward this state, the degree of organization and interconnection increases. These systems also exhibit a high degree of material loop closing. Materials are circulated through a web of interconnections with scavengers located at the bottom of the food web turning wastes into food. Even long-lived biological systems eventually succumb to environmental and internal stresses. They are not ideal models for a concept that implies flourishing forever. However, even in recent natural history they show stability during much longer periods than at any other times in human history. The steady state characteristic dif fers from the dynamic equilibrium models central to neoclassic economics.

INDUSTRIAL ECOLOGY AS NORMAL SCIENCE

So far I have argued that industrial ecology offers a new metaphor to reshape many of the basic notions within the modern paradigm. But it also has a powerful role in the normal stage of human activities. Allenby (1999) calls industrial ecology the "science of sustainability" (p. 40). I think it is more like a road map, but the ecological metaphor can be extended to encompass the discipline of ecology. Ecology is fundamentally a science of living systems. Ecology focuses on the interconnections and community character of a system and seeks to identify and characterize the web of energy and material flow that maintain its health. Adding the "industrial" half of industrial ecology, it is not difficult to conceive of a science of modern industrial societies that seeks to understand the intricate web of energy and material flows and discover the rules that govern robustness and resiliency in such systems. The holistic nature is appealing as a countervailing force to the ever more reductionist form of technical knowledge in vogue today.

The fundamental interconnectedness of an ecological system is appealing here as a metaphor and thus the transition from the earlier concept of industrial metabolism (Ayres &. Kneese, 1969) to that of industrial ecology-a way of describing modern industrial societies, particularly examining the flows of materials and energy just as one does in the ecology of natural systems. Furthermore, in this sense of industrial ecology, this expanded analytic or descriptive body of knowledge would become the basis for designing more effective technologies and institutional structures. It is hoped that the enlarged ability to incorporate processes more like those that occur in the world would avoid the unintended consequences that prior applications of less robust models have created. I am personally skeptical. I do not think that bigger and more complex models of, for example, the economic system would prevent further deterioration of justice and increasing maldistribution among today's global inhabitants and those to come in the future. The shortcomings lie in the hidden assumptions of the models.

Much of the early history of industrial ecology was, indeed, focused on flows. Ayres ( 1989) coined the term industrial metabolism as the web of flows of energy and material. But the ecological notion offers more than just an expanded holism. Other features of ecosystems suggest design principles directly without further analysis-thus, the road map I referred to earlier. Stable ecosystems are very parsimonious in their use of both energy and material. Material flows are essentially closed loops, with scavengers playing a critical role by converting metabolic wastes to food. Energy flows are thermodynamically efficient within the system, converting much of the solar energy captured by the system. Such stable ecosystems are thermodynamically steady state systems as opposed to equilibrium systems. Finally, stable ecosystems have evolved so that they are metabolically stable. None of the metabolic effluents of any of the component organisms act as a systemic poison or upsetting mechanism for any other. All exist together in a homeostatic or dynamically stable state.

Modeling an industrial economy as an interconnected system of energy, material, and money flows provides an analytic means to repair the breach inherent in both the economic and environmental sciences. Daly (1977) and others have stressed the importance of including material flows in economic analysis, noting the fundamental connections of economics to natural resources, quite the opposite to Solow's stance cited earlier in this article. Daly and earlier Georgescu-Roegen (1971) developed a steady state framework for describing modern economic systems and for designing policy, invoking basic laws of thermodynamics and ecological systems behavior as part of the grounding. Expanding the typically sectoral or firm-level models used by policy analysts and corporate planners to material and energy flows during the entire life cycles of economic goods, in theory, should reduce the probability of suboptimal solutions and of the appearance of unintended consequences.

Converting some of these notions into an industrial design context, it is reasonably direct to establish a set of simple design rules for the innovation of more environmentally sustainable products and services. Four such rules are (Ehrenfeld, 1997):

1. Close material loops.

2. Use energy in a thermodynamically efficient manner; employ energy cascades.

3. Avoid upsetting the systems metabolism; eliminate materials or wastes that upset living or inanimate components of the system.5

4. Dematerialize; deliver the function with fewer materials.

The Natural Step is another system of rules derived by analogy to natural ecosystems. The basic premise of the Natural Step is that materials cannot be indefinitely transferred from the lithosphere (the inanimate part of the earth's surface) to the biosphere (the life-supporting system) without eventually interfering with evolutionary patterns pathologically. This premise converts to a set of rules that are similar to those in the above list; for example, do not allow human-produced substances to accumulate systematically in the air, water, or land. Their argument like that in industrial ecology is to construct rules for designing industrial systems and their products of commerce from observations of natural system behavior. The founder of the Natural Step, K. H. Robert (1991), calls their framework a compass.

CONCLUSION

I would like to return to the idea of sustainability but in another context. Some 30 years ago, Paul Ehrlich ( 1969) used an identity, sometimes called the Master Equation, to illustrate the problems of increased population.

where

I = some aggregate measure of environmental impact; P = population; A = a measure of affluence or economic output, usually gross domestic product (GDP) per capita; and T= resource efficiency as materials or energy used or spoiled per unit of economic output.

This is an identity with each side having the dimension of impact. Now if we take today's impact (I) as sustainable and project population (P) and economic development (A) to double in the next several generations, the efficiency of materials and energy consumption should drop by a factor of 4 just to keep I constant. If one argues that present levels of output are producing unsustainable impacts, the reduction factor should be even greater. This simple relationship has produced a call by many for vastly improved technologies about 4 to 20 times more efficient than those they replace (von Weizsacker, Lovins, & Lovins, 1998). Even among these calls for dematerialization, there are some important differences. The Factor 4 notion calls for a relative increase in efficiency of use of natural resources. The Factor 10 Club argues for a tenfold absolute reduction of materials' flows.

Both the relationship and the suggested technological solution are appealing in their simplicity. von Weizsacker and his coauthors argue that many such improved technologies now exist, for example, a hyperperforming automobile capable of some 150 miles per gallon and virtually nonpolluting at the same time. I am not so sanguine and suspect that although such improvements are necessary for the creation of sustainability, they are insufficient. Their failings spring from two sources: One is simply the insufficiency of efficiency improvements to counter the absolute impacts created by growth occurring at rates greater than those of the improvements. Such growth is expected and projected by most models of near-term patterns of global development. Technological innovation is essential to achieving part of the possibility of sustainability and the simple design rules are very useful here.

There is no way to avoid the thermodynamic limits of energy consumption. We cannot recycle energy. Once all the useful work has been extracted, it is no longer of any value to human society, even though none of the energy has been used up. It has only been transformed. Materials, on the other hand, can be used over and over again, although not without costs in both economic and energy terms. The potential reusability of materials has been a subject of controversy following Georgescu-Roegen's (1971) intriguing work on entropy and economics. He argued that metals will become dissipated in use and eventually are lost to the economic system in a manner similar to the loss of utility of energy as the entropy increases. Modern systems for recovering and recycling materials attempt to mitigate these limits and maintain the viability of materials won from their original natural sources. This subject is one of the central ideas of industrial ecology.

Dematerialization and loop closing can bring much improved material efficiencies to new products and services. Information technology-replacing stuff with bits-an produce satisfaction without the burdens of material goods. This approach is very promising but not available for many important functions of everyday living. Some of the early promises of an electronic world have not panned out. Per capita paper consumption has continued to rise despite today's electronic office. Light weighting, a process that seems closely tied with industrial development (Wernick, Herman, Govind, & Ausubel, 1996), can also reduce material demands, but not more than a factor of 2 or so. There have been great reductions in steel and copper use in the past 50 years in the United States, but the result has been accompanied by increases in aluminum and plastics. Most of the concepts in the book Factor Four by von Weizsacker et al. ( 1997) are some form of dematerialization. On the other hand, loop closing, particularly multiple iterations as in a natural ecosystem, can lead to very large increases in material efficiency. Every time a material is recycled (and replaces a unit of virgin material) the intensity of use is cut by two. Recycle it twice and the factor is 4, and so on. Herein lies one of the simple secrets of ecological sustainability.

Industrial ecology as the "normal" science of sustainability (modifying slightly the phrase as used by Allenby) promises much in improving the efficiency of human use of the ecosystem that supports us. But, again, is it enough? Technological improvements are not always better in the full sense of sustainability. Those who argue that economies in an electronic world can be uncoupled from the current excessive dependence on natural resources lend, perhaps, some credence to Solow's assertion of 25 years ago. But technologies are not the solution to problems that confront us in dealing with equity, justice, dignity, and the satisfaction of other sustaining human concerns. Consciousness of the (un)sustainability of today's world raises many questions about what is better. Are new energy and material-conservative technologies that also produce unemployment better than the old? It is simply not enough to seek better ways of designing the world out of old patterns of thinking. In this sense, industrial ecology as science is inadequate. Its other face, paradigmatic possibility, offers a road map to different, not just better, designs for the future. Table 3 summarizes the characteristics of the two forms of industrial ecology.

Cooperation and community also are parts of the ecological metaphor of sustainability. In an interconnected world, autonomy is a paradoxical idea. Evolutionary theories in both nature and industrial organization point to the importance of competition. Natural systems operate, however, with a balance between competition and cooperation. Perhaps if that balance can be restored to society, other parts of the system will begin to come into balance as well, including the demands made on nature. Similarly, studies of traditional cultures built on strong community ties point to their power in maintaining central cultural values of justice and dignity, among others. Like other endangered species, these cultures have not sustained the onslaught of modernity. Can we have both modernity and sustainability? Industrial ecology suggests, on one hand, we have some serious thinking to do. But on the other, it offers a possibility to have both.

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