by Ian Ellingham, PhD, PLE, FRAIC
A major theme of our times is the powerful idea of sustainability. Yet, for the practical decision-maker working in the built environment, choosing between alternatives in an attempt to maximize project sustainability is rarely easy, because true sustainability involves fulfilling three frequently conflicting factors: economic, social and environmental. For example, if an existing project is not economically viable long term, it is likely to be demolished and the care put into achieving environmental sustainability will have been wasted. Searching questions must be asked, conflicting and uncertain information dealt with, and trade-offs made.
Even within the environmental factor, how might one balance resource utilization, energy consumption and carbon dioxide (CO2) emissions? Ideally, some discerning analysis should be undertaken. Quantitative methods are important in moving towards real sustainability, and even a basic understanding of the principles behind them can help increase one’s capabilities as a decision-maker.
Making sustainable decisions
We all make decisions, in our personal and business lives. Do we choose Alternative A or Alternative B, or look for something else? Choosing one thing almost inevitably means not selecting something else. Monetary resources are usually limited. Should money be spent on a higher-performing structural system or more prestigious floor finishes?
Humans make these sorts of decisions, but so do animals. Just think of the antics of your family dog: Does it go for the food or the friendly pat?
Sustainability is a complex concept, and is often misunderstood and misrepresented. A few key elements are worth keeping in mind. The fundamental feature of the concept of sustainability is how it deals with the longer term—ensuring society or some element of society can thrive over a protracted period of time. Decisions about buildings can have long-term implications, and those about urban environments even longer. One city councillor of a European city once said a big problem was the main roads into the city were established by the Roman administration when it was just a village of a few hundred people.
Sustainability implies considering intertemporal decisions, decisions relating and balancing flows of resources occuring at different times. We do something in the near future, in anticipation of someone receiving some benefit in the more distant future, or at least not having their future well-being undermined. As a result, many questions arise.
Objectives of an analysis
The objectives of an analysis for sustainability are reasonably clear, and in many ways are not much different from strictly economic objectives—both are seeking balance, neither overinvesting nor underinvesting. It is very easy to overinvest in the pursuit of environmental concerns, initially paying too much to achieve future benefits that may not materialize, or may be of little value to future generations.
Humans are very capable decision-making machines, capable of integrating more information and subtleties than any computer program (so far) and making judgments about risk and future possibilities, yet are also replete with biases and prone to fall into all sorts of traps. Different people will offer different opinions. How do you tell whose assessment is best? Hence one of the objectives of a quantitative analysis can be to verify decisions made on the basis of expert informed intuition.