to know how any individual action affects the environment. LCA is being developed to produce a framework within which this information can be collected, refined, and acted on.

However, analysis of any kind is limited in its ability to resolve complex problems, particularly when an action has consequences that advance some objectives while hindering others. Under these conditions, the choice among alternatives must incorporate not only analytical elements, but strategic ones as well. LCA is well suited to supplying the former but not the latter.

Life-Cycle Analysis

The basic objective of LCA is to guide decision makers, whether consumers, industrialists, or government policy makers, in devising or selecting actions that will minimize environmental impacts while furthering other objectives. Decision makers must use this tool in concert with traditional criteria for selecting one action over another, including economic, engineering, and social goals.

The life-cycle paradigm requires the consideration not only of the immediate impacts of a product or process choice, but also of the products and processes that gave rise to that choice and of those that occur in response to it. This view reflects the notion that "industrial ecosystems," like natural ecosystems, are vast networks of interconnected activities. In such networks, the size of a particular change does not necessarily indicate the scope of its effect, and care must be taken to avoid changes that maximize local benefits at the expense of global effects.

LCA is a three-step process:

  • inventory analysis, or the identification and quantification of energy and resource use and environmental releases to air, water, and land;
  • impact analysis, or the technical qualitative and quantitative characterization and assessment of the consequences of resource use and environmental releases for the environment; and
  • improvement analysis, or the evaluation and implementation of opportunities to reduce environmental burdens (Vigon et al., 1993).

The three stages of LCA reflect classical technical decision-making procedures. In each case, a control volume is identified. Resource flows into the control volume and waste emissions from the control volume are then measured. The next step is to determine the relationship between these resource and waste fluxes and the underlying scientific and technological principles. Finally, the problem is resolved based on the insight gained from these principles and the objectives of the analyst.

Much of the focus on LCA has been on how and why it is used. Organizations such as the Society of Environmental Toxicology and Chemistry and the



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