INDUSTRIAL ECOLOGY HUMAN ACTIVITIES AND GLOBAL
ECOSYSTEMS
The field of Industrial Ecology was created to inform purposive human decision making
about industrial production processes, especially as they impact the environment, by
taking advantage of knowledge about the functioning of successful ecosystems. More
recently the scope of the field has enlarged to include decision-making regarding
consumption activities as well. Human decision-making is important because humans,
while one species among many, are responsible for dramatic and far-reaching changes to
the global environment and thus to the existence of other species.
Industrial Ecology is not the only new, cross-disciplinary field employing the word
"ecology." Among others utilizing the ecological metaphor are the Ecology of the Family,
Organizational Ecology, and Ecological Economics [see entry in this volume]. In all cases
the intention is to suggest that the field in question constitutes a complex system, in some
instances with direct relations to biological ecosystems. The Ecology of the Family focuses
on how family members are shaped by their interactions, both competitive and
mutualistic, with one another.
Organizational Ecology applies population dynamics models to the births and deaths of
firms and industries and examines how the evolution of organizational structure is shaped
by competitive and cooperative interactions. Ecological Economics departs from the
observation that natural ecosystems uninfluenced by human activity no longer actually
exist: counting both economists and ecologists among its numbers, it attempts to
integrate the two professional domains.
Industrial Ecology is distinctive in its focus on the industrial system, literally treating it as
an ecosystem or, more exactly, the subsystem of principal interest within a more inclusive
ecosystem. The flows of energy and material characterize an industrial system and serve
as the integrating focus of all description, design and analysis in Industrial Ecology. Not
merely analogous to the flows of energy and material in ecosystems, they actually
constitute those flows. The production and consumption activities of humans can be
described in terms of these flows just like the activities of any other animal. Given this
focus on industrially valuable resources, it is not surprising that most of the field’s
founders were engineers or applied physical scientists with interests in chemical
processes and effluents and, more generally, the reduction, reuse, and recycling of
industrial wastes. Industrial Ecology is motivated by its concern for the well being of the
environment.
As the inclusion of ecology in its name indicates, it puts special emphasis on developing
and implementing solutions and policies at the system level, up to and including the global
system. Central to the system perspective is the concept that the behavior of individual
components cannot be fully understood without reference to the system in which they
interact. Industrial Ecology explicitly recognizes that human industrial activities in the
modern industrialized world are characterized by the interdependence of many
industries, each industry itself often performing many interconnected production
processes, all reliant on inputs of energy and materials and discharging wastes.
System scientists have long understood that the basic features of a system of interacting
components need to be understood in a top-down fashion, even though many processes
operate at the level of component parts. In the case of system design, top-down and
bottom-up contributions generally proceed in an iterative fashion. This system
perspective influences the direction that Industrial Ecology takes in confronting
environmental challenges: improving the environmental compatibility of individual
industrial processes is evaluated in the context of improving the overall industrial system.
A simple illustration is provided by Figure 1, which combines two waste streams, fly ash
from coal-fired power plants and waste plastic from plastic manufacturing, into a useful
product, light-weight building blocks.
At the same time the waste heat and carbon dioxide from the power plant can be supplied
to a large-scale greenhouse, leading to increased production of fruits and vegetables.
Reducing any of these waste streams might both increase the unusable waste from the
others while also reducing the quantity of useful product. Recognizing the value of waste
as a resource is a major theme of Industrial Ecology. <Figure 1 near here> The tracking of
resources, intermediate products, final products, and wastes can be conducted at the
level of business establishments, towns, nations, or in the context of nations interacting
in the global economy.
And the analysis of these flows, as a basis for action, can also take place at all these levels.
II. Resources and Products in Industrial Systems The industrial system and the natural
system were long seen as separate although overlapping domains. Economists, for
example, used to treat resources as “free gifts of nature” and therefore exogenous to
their concerns, limiting the designation of so-called factor inputs to built capital and labor.
(Many still do, contrasting the ‘built environment’ with the natural environment.)
It was a contribution of Industrial Ecology to treat the industrial system as a subsystem of
the natural system (see panel a of Figure 2). As Industrial Ecology now broadens its
concerns to include consumption as well as production, this simple diagram is being
reconsidered because of the importance of human motives and human agency to the
decision-making process. The built environment is part of the biophysical structure of the
social-ecological system and subject to the laws of nature (see panel b of Figure 2), but
the cultural sphere is better understood using the concepts and methods of the social
sciences.
<Figure 2 near here> In the earliest societies, the built environment was insignificant.
Humans in hunter- gatherer societies, like all other species, primarily take what nature
makes available. They are not likely to severely overexploit a local ecosystem; when
resources become scarce, they move on. However, even before the advent of agriculture,
humans began to modify their local environments for the purpose of increasing its
productivity (for humans) through the use of fire. With the transition from hunter-
gatherer to settled agriculture, farming and herding societies greatly extended the
modification and control of the natural system to overcome natural supply constraints
and produce more of what humans desired. This control allowed for the possibility of
individuals or groups producing more than they required of agricultural and other goods
and thus making some of their production available for trade. With the development of
trade and of markets, agricultural and other types of output were converted into
products: goods (or services) exchanged for something else of value. A second and related
historical transition is the explosive growth of human requirements, the average of what
is considered standard in a given society, and the related changes in human consumption
patterns.
Early human requirements differed little from those of other social mammals, were
closely related to physical survival, and were met by the output of nature. In modern times
humans are unique among ecosystem species in the volume, variety, and sources of their
material requirements. Consumer demand in affluent societies is met by an extensive
array of products -- the goods and services output by the industrial system. Humans are
not alone in producing products, but no other species even approaches the scale of
human production. The modern built environment reflects the prevalence of these
human products.
While the flow of mass and energy in ‘natural’ ecosystems is largely dictated by the
consumption of resources to supply energy and nutrients to sustain life, many if not most
products of modern industry have little to do with directly providing energy and nutrients,
and a substantial number have little to do with that function even indirectly. The extent
to which industrial systems are dedicated to producing such products contrasts them to
the rest of the natural system. Industrial Ecology is concerned with a unique feature of
these industrial systems: the unprecedented degree to which the appropriation of
resources -- materials and energy -- for the fabrication of products is not bounded by the
metabolic constraints of the biological world, both in the quantity of those flows and in
the variety of materials involved. One could say that humans in a modern consumer
society have developed extended metabolic needs, where consumer goods and services
play a role similar to the need for proteins and carbohydrates in nature.
To have toast in the morning requires not only bread but also a toaster and thus electric
power as well. This concept of humans having extended needs is hardly new. Rousseau
saw industrialization as creating a set of artificial (as opposed to natural) needs, and Marx
made the distinction between human and inhuman needs. The material and energy
requirements of the modern industrial system serve the extended needs of human
consumers. The concept of distinct industrial metabolisms, reflecting the material
realities of specific societies, and attempts to quantify them, is an active research area in
Industrial Ecology. Since the majority of industrial products do not satisfy biological
metabolic requirements, they need not be composed of organic material. The relaxing of
this constraint, coupled with the specialized functions of many products, leads to the
development and use of a
