Whether one defines sustainability broadly with respect to the global environment or narrowly with respect to a particular industry or technology, one characteristic stands out as a hallmark trait. In the broadest terms, sustainability is the idea that our actions today should not ignore the effects on future generations of life on our planet. This of course gives rise to the notion that were it not for humans, nature would be inherently sustainable for eternity, which is a fine point for philosophers and astrophysicists to argue, but not practical for our lifetimes. We have the ability to alter our environment to meet our present and future needs in a way that other species do not. This is no surprise, but there are critical implications for our future depending on our implementation of this philosophy in the present.
For all of our good intentions, we are faced with a persistent paradox and conflicting goals. We are capable of predicting the future with much greater power than our ancestors, but with that ability comes even greater uncertainty. We may model such complex physical systems as global climate, but lack the ability to predict our ultimate fate due to the chaos around us. We therefore are no further toward the goal of reducing or eliminating unintended consequences of our actions, since our actions can still only directly affect the present. Once the dice are cast, there is no turning back.
How do civil engineers fit into this paradigm? Our projects’ design and construction often span a decade, but their long-term effects may not be known for many years. We also deal with municipal systems for water and wastewater that must efficiently serve our communities for 50 years or longer and expand to accommodate additional demand. But these systems, especially underground, hold little promise for adaptation if the conditions under which they were designed change over time. The point of these examples is to highlight the shortcomings of even the best designs and intentions, since all designs are subject to similar constraints on time and money. And the more complex the design, the more prevalent are the uncertainties.
Consider also our efforts to reduce dependence on limited fossil fuels in favor of renewable energy. Such sources include wind, hydroelectric, and solar among others. We think of these as elegant solutions to our energy needs, since the sources of the energy will likely outlast our time on this planet. Nevertheless, in nature nothing is free, and the universe is governed by the laws of thermodynamics. Every watt of power generated by the wind or the sun is a watt of energy that is not entering the "environment" but is rather captured for our present benefit. Might these incremental subtractions someday become a driving force for some other doomsday scenario? Just as our early dependence on oil and coal seemed eternal, eventually the consequences became apparent. But we are fooling ourselves if we believe that the "next big thing" will be the last. If there is one thing that has remained constant, it is our ability to grow and adapt to our environment, and our technology will continue to advance to take advantage of new opportunities.
If indeed we owe a duty of care to future generations-and I believe that we do-we can only be obligated to act with the tools that we have at hand. But our predictive power is still relatively young and limited. One of the ways to continue forward is to further expand our collective knowledge and emphasize science and mathematics in education. It is through science-the strict study and application of nature’s laws-that we will attain a deeper understanding of the complexities of our environment. Absolute sustainability may be an unreachable ideal, but sustainability of our civilization in the midst of shortsightedness need not be.
The topic of this column was inspired by "Environmental Ethics: Sustainability, Competition, & Forestry," Chris J. Macdonald, ed., 1992; posted online at http://www.ethics.ubc.ca/papers/susdev.html