Sustainability Research's Definition of Sustainability
Version 2.0 Posted March 12,2004
First Posted: Oct. 2003
The goal of this analysis is to clarify Sustainability Research's definition of sustainability.
Sustainability Definition
The working definition of sustainability for the explorations of Sustainability Research is:
"A sustainable system is one where the amount of output from the system does not exceed the amount of input. Put another way: for a practice to be sustainable it must not use up any resource faster than that resource can be replaced."
Notice that the determination of sustainability is dependant upon both the rate a resource is being used and the rate the resource is being renewed. Because of this it is not possible to specify a resource as sustainable. Oil can be sustainable if it is not used up more quickly than the earth creates it (the pollution created by oil use may not be sustainable however depending on how fast the earth cleans itself). You can only define a system to be sustainable or not. Ultimately it is impossible for the earth to be sustainable since we are told by those who know that the sun will be enveloping our planet some billions of years in the future. The sun's demise, however, is far enough out that we can assume the sun exists for purposes of human considerations. The text below expands upon the terse definition above.
Defining the Boundaries
The sustainability definition applies to all situations but complications arise when it is applied to a specific discussion. To talk about sustainability you must define the system you are considering. A system may have a geographic boundary (a town, a state, a country), a product boundary (is the manufacture of widgets sustainable), or an entity boundary (is corporation "Makes a Lot" sustainable). There is some overlap in these definitions as you might think a company has a certain physical location which would be a geographic boundary. While true, the sustainability of the company probably extends beyond the property. Employees of the company may use the airlines, for example, and for the company as an entity to be sustainable, those flights would have to be considered in the sustainability analysis. For the purpose of illustration, in this analysis we use a geographic boundary and define the system under consideration to be the physical entity of a house ("physical entity" implies just the house building and not the fact that it is home to people who travel and work etc. To take into consideration all the elements of home, the boundary of "family" could be used).
After the system is defined, further narrowing can be done by specifying the system elements to be considered. To determine the complete system sustainability all system elements have to be included, but for some analyses only a few may be of interest. A couple of element examples for a house would be lumber for shelves and natural gas. There is also the aspect of the system element that must be considered. What is meant by aspect will become clear in the following examples.
For the System: House and System Element: Lumber it could actually be sustainable in that all wood for building shelves that is brought into the house will be, at some point, taken out of the house again. This fits the definition of sustainability. Here is where aspect fits in. The aspect of that system component may have changed: what went in as usable lumber comes out as unusable scrap wood. If the aspect of the lumber is usable lumber then the house may not be sustainable, while if the aspect is merely wood, in any form, then the lumber element of the house is sustainable.
Similarly for natural gas. Natural gas with Aspect: Natural Gas is not sustainable in the house system. Natural gas is piped in, burned for heat and there is no way for the house to at some point return natural gas to the pipes. If, however, the aspect under consideration is the energy of the natural gas, it may be possible for the house to be sustainable, as a house can generate energy if included in the house system is the sunlight falling on its roof. As you can see, the answer to the question "Is it sustainable?" will depend greatly upon what "it" is.
A subset of the sustainable systems is the closed system. A closed system is one where there is no input or output. All needs of the system are fulfilled within the system. If this system can exist indefinitely than clearly it is a sustainable system. The earth-sun-moon system can be viewed as almost a closed system when it is looked at from the human time and space scale. The sun will eventually burn itself out, the earth exhausts energy to the vacuum of space, and the three heavenly bodies do rely upon the rest of the universe for their motion and existence, but for our purposes this system can be considered closed.
Domains of Sustainability
Sustainability Research's primary focus is on technological aspects of sustainability, but it is important to recognize the human aspect. Many sustainability indices include consideration of some form of human well being - whether humans can live conformably under the conditions imposed. Human contentedness is recognized by Sustainability Research as a resource that must be considered when complete sustainability is being examined. The following is a list of all the categories a resource might fall into:
* Pollution Absorbency (the quantity of harmful substances a system can absorb)
* Physical Resources (like trees, metals, water etc.)
* Energy (how much energy is used and where it comes from)
* Human Contentedness (are people satisfied)
All categories are of equal importance.
Though all categories will be investigated by Sustainability Research, to begin with the primary focus is on the use of energy. Obviously using energy emits large quantities of pollution and also uses up physical resources so it is impossible to focus on only one category when looking at sustainability.
Humans, Sustainability, and the Environment
There are many discussions about the environment that progress as if humans were not a part of the global ecosystem. Making the statement that the earth would behave a certain way "naturally" has no meaning -- as if the natural environment does not include humans. We are an integral part of this planet and are not extricable from the rules that govern life on it. There is no place on earth that is not impacted by the presence of humans, even those places where humans are not physically located. To live fully on this planet we must accept that we are part of it and not an "other" that is imposed upon the "natural" world around us. Sustainability Research is interested in the sustainability of humans and in tandem with that believes that a healthy and diverse environment is a critical part of human sustainability.
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