"Sustainable development" has become the leading environmental theme of our time. Like most great issues, the discussion about sustainable development involves an argument about our future. It is a concept of both common sense and controversy. It reflects common sense because no one is for a mode of life that diminishes our capital stock, which would make future generations poorer, or degrades our living conditions, which would make current and future generations less healthy. Yet sustainable development is also a subject of controversy because of the difficulty of comprehending the myriad linkages between environmental factors in a dynamic world.

Clashing conceptual frameworks lead to widely varying conclusions about what constitutes "sustainability." Still less is there any clear direction for public policy with regard to sustainability; at this point the policy discussion resembles the Woody Allen gag about trying to find a framework to turn a concept into an idea. The conceptual difficulties with the issue arise chiefly because of a lack of clarity and definition about what "sustainable development" means.

Most discussion begins with the UN World Commission on Environment and Development's 1987 definition: "To meet the needs of the present without compromising the ability of future generations to meet their own needs." This definition is too vague and general to be helpful. The President's Council on Sustainable Development, which has been laboring over the subject since 1993, recognizes this definition to be "inexact." Even some environmental groups have expressed misgivings about the plastic nature of sustainable development. Greenpeace once described sustainable development as the "deceptive jargon" of anti-environmentalism.

 

Some Alternative Definitions of Sustainable Development

"Sustainable utilization is a simple idea: we should utilize species and ecosystems at levels and in ways that allow them to go on renewing themselves for all practical purposes indefinitely."

—Robert Allen, How To Save The World (Totowa, New Jersey: Barnes & Noble Books, 1980), p. 18

 

"Sustainability might be redefined in terms of a requirement that the use of resources today should not reduce real incomes in the future."

—Anil Markandya and David Pearce, "Natural Environments and the Social Rate of Discount," Project Appraisal, Vol. 3, No. 1, 1988, p. 11

 

"The core idea of sustainability . . . is the concept that current decisions should not impair the prospects for maintaining or improving future living standards . . . . This implies that our economic systems should be managed so that we live off the dividend of our resources, maintaining and improving the asset base."

—Robert Repetto, The Global Possible—Resources, Development, and the New Century (New Haven: Yale University Press, 1985), p. 10

 

"Sustainable development implies using renewable natural resources in a manner which does not eliminate or degrade them, or otherwise diminish their usefulness to future generations. . . Sustainable development further implies using non-renewable (exhaustible) mineral resources in a manner which does not unnecessarily preclude easy access to them by future generation . . . . Sustainable development also implies depleting non-renewable energy resources at a slow enough rate so as to ensure the high probability of an orderly societal transition to renewable energy sources."

—Robert Goodland and G. Ledec, "Neoclassical Economics and Principles of Sustainable Development," Ecological Modeling, No. 38 (1987), p. 37

 

"[Sustainable development is] development without growth in throughput of matter and energy beyond regenerative and absorptive capacities."

—Herman Daly and Robert Goodland, "Environmental Sustainability: Universal and Non-negotiable," Ecological Applications, Vol. 6, no. 4 (1996), p. 1002

 

Sustainable development is of little use if it is just a "motherhood and apple pie" concept. Until a more exacting definition of sustainable development is found, it will be a solution in search of a problem, not unlike the evanescent enthusiasm for "participatory democracy" in the 1960s. Ultimately this does a disservice to sound environmental policy and to the idea of sustainable development itself. Environmental scientist Timothy O'Riordan warned in 1988: "It may only be a matter of time before the metaphor of sustainability becomes so confused as to be meaningless, certainly as a device to straddle the ideological conflicts that pervade contemporary environmentalism."54

The one seemingly clear application of the concept of sustainable development is global warming, i.e., if the temperature rise from CO2 emissions will cause catastrophic consequences, then our current way of life is unsustainable and will have to change. But is this conclusion as clear cut as it seems?

Leaving aside the issue of whether the catastrophic scenario of global warming is firmly established and predictable, what the imperative of sustainability requires us to do is not self-evident. A prominent theme is that we should abide by the "precautionary principle," i.e., that we should undertake significant changes in our mode of life just in case the catastrophic scenario comes to pass. Aside from the tenuous logic of the precautionary principle (which could readily justify a multi-trillion dollar space-based "precautionary" defense against asteroids striking Earth), it is arguable whether mankind would be better able to sustain itself and the rest of nature in the face of such change with the technology and wealth that will be accumulated with further growth. This weakens the case for requiring a vast transformation in our mode of life through institutional and policy means that remain murky and speculative, not to mention expensive. We won't begin to solve the issue here, but a few observations are in order.

The core idea of sustainable development is that future generations will have the means to meet their own needs better than we are able to meet our own today without degrading the natural environment. This implies that there will be adequate resources for future generations, and that sufficient care should be taken not to pollute our air and water, and not to despoil our forests and biological habitats. This suggests that the question can be divided into two halves: resource use and pollution. When thinking about resources, it is further necessary to divide them into two categories. The renewable resources include forests, water, food supplies, and animal species, while fossil fuels and minerals are non-renewable.