1. What is sustainable development? Concepts and constraints
1.1. Sustainability of human society
There is only one alternative to sustainability: unsustainability. But sus- tainability involves a time dimension: unsustainability now rarely implies an immediate existential threat. Existence is threatened only in the distant future, perhaps too far away to be properly recognized. Even if threats are understood, they may not cause much concern now: there still seems to be enough time for them to disappear, or for finding solutions.
In the past, the sustainability of human society was not really at stake: the glacial change of its environment left plenty of time for adaptive response and evasion.
Threats to sustainability of a system require urgent attention if their rate of change begins to approach the speed with which the system can adequate- ly respond. As the rate of change overwhelms this ability to respond, the system loses its viability and sustainability. The sustainability of humankind is now threatened by both of these factors: the dynamics of its technology, economy and population accelerate the environmental and social rates of change, while growing structural inertia reduces the ability to respond in time. Response time lengthens while respite time—the time available for adequate response—shortens:1 the sustainability of human society becomes an urgent concern.
Sustainability in an evolving world can only mean sustainable development
In previous times, sustainability of humankind was taken for granted and did not appear as an explicit goal. It certainly was an implicit goal: no human society has ever consciously promoted its own unsustainability.
Global developments now focus attention on sustainability as an explicit goal. But the concept has to be translated into the practical dimensions of the real world to make it operational. We must be able to recognize the presence or absence of sustainability, or of threats to sustainability, in the systems under our stewardship. We need proper indicators to provide this information, to tell us where we stand with respect to the goal of sustainability.
To sustain means “to maintain; keep in existence; keep going; prolong.”2 If applied only in this sense, sustainability does not make much sense for human society. Human society cannot be maintained in the same state,whatever it should be. Human society is a complex adaptive system embed- ded in another complex adaptive system—the natural environment—on which it depends for support. These systems coevolve in mutual interac- tion, and they each consist of a myriad of subsystems that coevolve in mutual interaction. There is permanent change and evolution. Moreover, this ability for change and evolution must be maintained if the systems are to remain viable (able to cope with their changing system environment) and sustainable. The sustainability goal translates more accurately into a goal of sustainable development.
Different concepts of sustainable development
How do we define sustainable development? One of the most commonly cited definitions stresses the economic aspects by defining sustainable devel- opment as “economic development that meets the needs of the present gen- eration without compromising the ability of future generations to meet their own needs.”3 Another takes a broader view by defining sustainable develop- ment as “the kind of human activity that nourishes and perpetuates the his- torical fulfillment of the whole community of life on earth.”4
There are many ways of securing sustainability, with very different conse- quences for the participants. Nature has successfully demonstrated sustain- able development for a few billion years, with blind disregard of the fate of individuals and even species. The principle of survival of the fittest with its effectiveness and dynamics, but also its cruelty and hardship, would not be accepted as a principle for sustainable development by the majority of humankind.
Some human societies have been sustainable in their environment over long periods of time by institutionalizing systems of exploitation, injustice, and class privilege that would be equally unacceptable today for most of humankind.
If we would achieve environmental sustainability coupled with a continua- tion of present trends, where a small minority lives in luxury, partly at the expense of an underprivileged majority, this would be socially unsustainable in the long run because of the stresses caused by the institutionalized injus- tice. And an equitable, environmentally and physically sustainable society that exploits the environment at the maximum sustainable rate would still be psychologically and culturally unsustainable.
Sustainable development of human society has environmental, material, ecological, social, economic, legal, cultural, political and psychological dimensions that require attention: some forms of sustainable development can be expected to be much more acceptable to humans and, therefore,much further away from eventual collapse than others. A just and fair soci- ety, for example, is likely to be more securely sustainable than a materially sustainable brutal dictatorship.
The sustainability concept we adopt has consequences: our interpretation of the concept directs our focus to certain indicators at the neglect of oth- ers. Conversely, if we rely on a given set of indicators, we can only see the information transmitted by these indicators, and this defines and limits both the system and the problems we can perceive, and the kind of sus- tainable development we can achieve.
1.2. Sustainable development is constrained by what is accessible
There are numerous constraints that restrict societal development. A few can be negotiated to some degree; most are unchangeable. The total range of theoretical future possibilities is reduced by these constraints, leaving only a limited, potentially accessible set of options, the accessibility space (Fig. 1). Societal development—whatever its form—will be restricted to the remaining accessibility space. Everything outside is fiction, and only con- fuses the discussion. However, within this accessibility space, there is still a broad spectrum of options and possible paths. This leaves choices, and it introduces subjective choice and unavoidable ethical decisions.