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ENVIRONMENTAL SYSTEMS MANAGEMENT, SUSTAINABILITY THEORY, AND THE CHALLENGE OF UNCERTAINTY
Citation:
Cabezas*, H C. ENVIRONMENTAL SYSTEMS MANAGEMENT, SUSTAINABILITY THEORY, AND THE CHALLENGE OF UNCERTAINTY. Presented at Applied Optimization under Uncertainty Conference, Carnegie Mellon University, Pittsburgh, PA, 9/16-18/2001.
Description:
Environmental Systems Management is the management of environmental problems at the systems level fully accounting fo rthe multi-dimensional nature of the environment. This includes socio-economic dimensions as well s the usual physical and life science aspects. This is important because all environmental problems are multidimensional in both a causative and a symptomatic sense. The mission of the Environmental Systems Management Research program at the USEPA is therefore, to construct a strategy for sustainable environmental management that coherently addresses the physical, biological or ecological, legal, economic, and social dimensions of the system. An overview of this program will be presented. One important aspect of Environmental Systems Management is the construction of a holistic theory of sustainability. Such a theory can provide criteria on what is a sustainable system and guidance on system management. An effort is underway to devise a theory. Starting with a food web, open to energy but closed to mass, with ten biological species and a nutrient pool, we built an ecological model to simulate its dynamic behavior at the species population and trophic level. Discretization of the phase space trajectory of the system forms the basis for a probability density function for observing the system in any particular state. From the probability function, the Fisher Information is computed as a function of time under various regimes including seasonal growth cycles, climatic changes, and loss of species. The Fisher Information is the maximum amount of information obtainable from a given set of observations and is a measure of system self-organization. The criterion that we hypothesize is that a system in a sustainable state neither gains nor loses Fisher Information with time. Future efforts in the theory include the addition of economic and social principles. An outline of the theory with simulated results will be presented. One critical challenge that arises in both Environmental Systems management and Sustainability Theory is uncertainty. The challenge is that for the complex ecological-social-economic relevant to sustainability we have: (1) difficulty determining the appropriate state variables of the system, (2) difficulty accurately measuring any state variables, and (3) missing relationships between the state variables of the system. All these contribute to major uncertainty in the accuracy and usefulness of any model, result, or simulation. This is inherent to the nature of the system not an after-the-fact complication. Yet the question of sustainability is so critical to the future existence of humanity, that the scientific community would default in its most basic responsibilities by ignoring the issue.