Defining Sustainability and Sustainable Development


to maintain, hold, or support the existence of a process, dynamic system, or dynamic system state over an extended period of time.


1) The ability of a dynamic system to maintain a relatively steady state or constructive development pattern for an extended period of time.

2) The ability of a social-economic system to provide sustained social development and quality of life improvements within a resource-constrained ecosystem.


Definition (2) is not at odds with the UN sponsored Brundtland report (1987) definition of sustainable development: “development which meets the needs of the present without sacrificing the ability of the future to meet its needs.”   Definition (2), however, explicitly acknowledges that our society is a dynamic system operating with constrained resources.

Definition (2) is also similar to Herman Daly’s concept of a “steady-state” economy with social and technological development.

A steady-state economy, in Daly’s description, is an economy in which the flow of inputs and outputs is steady and sustainable into the future.  This does not preclude development within the steady-state economy:  new products can emerge, old products disappear, education and healthcare can improve, and so on.   A stable or slowly declining population is presumed, since an increasing population inevitably requires an increasing flow of resources.

From a public relations point of view, however, “steady state” is not a desirable term. Regardless of how it is technically defined, it sounds like nothing changes, and there are too many people suffering for that to sell.  Even the concept of a pastoral, abundant steady state is not attractive to many people who thrive on change.

Although Daly and others correctly point out that efficiency improvements cannot go on forever, we can still envision technological transformations that will allow us to produce goods using far less resources than we do now.   This isn’t an argument that we can afford to continue existing policies.  But sustainability is not incompatible with higher standards of living, including even more material goods.

Daly points out that technology cannot fully substitute for resources.   He uses first the undeniable example that you can’t keep increasing the catch of fish by building more boats, because the ocean has a limited number of fish in it.  The truth of that statement is now very evident in declining world fisheries.  However, Daly also likes to suggest that you can’t build the same house with half the wood and twice as many saws.   That example is not so strong.  You can’t build the same house, perhaps, but you could build a better one.  [The wood could be sawed into thin layers, then made into plywood with air gaps, increasing both strength and insulation value.]  That would, of course, require lots of energy to run the saws and machinery.

Sustainability means living within the limits of renewable energy and resources. And there is no doubt that in the near term (at least 50 years), we have no way to increase total usable energy while reducing fossil fuel use.  But in the long run (beyond 50 years) we can, through highly efficient solar energy systems, wind, wave and geothermal systems, and well-protected, low-waste nuclear generators.  Advances in materials science will allow us to build shelters and material goods with a fraction of the material resources used today.  Advances in bioscience may lead us to engineered food production systems that require less space, water, fertilizer and energy to produce protein rich, nutritious and hopefully tasty food.  Manufacture for recycling will allow us to reduce the waste of matter dramatically.  One can imagine robotic technologies that mine our existing landfills for recyclable matter.  A vision of a sustainable economy can be a vibrant, developing economy in which production of value increases while consumption of non-renewable resources decreases.  A sustainable economy can include a human society that delivers more good to its members, even while enriching, rather than degrading, the ecosystem we live in.

Our urgent need to move to a sustainable economy is a social development problem as much as a business and governmental problem.  Terminology must be evaluated from a “marketing” point of view as much as an academic point of view.  Negative terminology like “steady-state” or “zero-growth” should be avoided in favor of positive terms like “sustainable development”.  We have to make it really clear that our current model of economic growth is actually making us poorer, but that an alternative exists that can lead us into prosperity.

Keys to Sustainable Development:

  • Stabilization of population through education, healthcare, and standard of living improvements
  • Incentives for resource and energy use efficiency (and disincentives for consumption)
  • Incentives for alternative (renewable) energy development (and disincentives for fossil fuels)
  • Protection of biological assets from depletion
  • Widespread Ecological and Econosystemics literacy
  • Governmental policies focused on Quality of Life, not GDP

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2 Responses

  1. Chip Pitts says:

    To your list of prerequisites for sustainable development, I would explicitly add “human rights” (although it’s there implicitly already). This is an established body of social norms and even of jurisprudence that represents the most widely approved global values in human history. It’s thus a uniquely valuable guide to the quality of life and social development dimensions of the problem, as recognized for example by the growing numbers of businesses that are joining governments and NGO’s etc in committing to the Universal Declaration of Human Rights.

    On Daly’s question of whether and to what extent technology can help achieve sustainable development, I’m actually a bit more optimistic than he is. Technology has offered and can continue to offer many solutions to the sustainability challenges we currently see. That doesn’t mean that we should assume that the needed technologies will come, and solve all our problems (as, say, the industry-funded Competitive Enterprise Institute and its allies argue). But historically the power of technology (e.g. enhancing agricultural yields) did manage to avoid the otherwise scary dilemma Malthus identified about population expanding exponentially but food production expanding only linearly.

    While Star-Trek type visions such as food replicators, transporters, dilithium crystals producing clean-burning energy, and an economy without money may seem utterly utopian at present, they all have analogues today that might help us make the leap to the next stage of human evolution. There are even some long-shot “breakthrough” solutions that could in theory solve the energy situation before 50 years from now.

    The problem is, again, we can’t just assume such things will happen. We’re all part of either the solution or the problem (or, more usually, both). And we already know that the challenge is as serious as can be — even existential for our species and most others on the planet. So in the meantime we urgently need not only to emphasize efficiencies and conservation and changes in unsustainable lifestyles, but also to invest in and strongly advocate for alternative energy and other sustainable technologies in order to help create that more sensible future.

  2. Bryan K Long says:

    I think you are right, but want to see that argument detailed out a little, and am having trouble coming up with a tight argument. There is the argument by induction, that the world’s most prosperous and developed nations have the most protections for human rights, therefore human rights are likely a factor in prosperity. But prosperity is not sustainability. There is the argument that sustainability isn’t worth much to people who live in fear, but that makes it a key to happiness, not sustainability. More effectively, we could argue that without rights there will be never be sufficient social morals to protect the future. That certainly makes some sense: a manipulative class exploiting the underclasses is likely to exploit the rest of the ecosystem as well, without much thought to sustainability. But give me more on this.