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Science  02 Feb 2007:
Vol. 315, Issue 5812, pp. 573
DOI: 10.1126/science.1139909

The theme of this year's annual meeting of the American Association for the Advancement of Science (AAAS) focuses on sustainability and the need for scientific efforts to guarantee it. In next week's Editorial, AAAS President John Holdren will point out that human well-being has multiple dimensions and that the goal of sustainable well-being aims at improving all of them. His analysis focuses appropriately on how to manage our energy resources sustainably.

In its most straightforward formulation, sustainability would require that a resource be technically managed in such a way that its contribution to human welfare is conserved or improved for succeeding generations. But because the term has gained iconic status in the language of environmental conservation, it's hardly surprising that it now carries a lot of freight—in particular, a cargo of economic, social, and ethical assumptions and preferences, leading to different standards and expectations. In the interest of thinking about these before the forthcoming meeting, here are three sample sustainability scenarios we might explore.

First, the human population is growing, rapidly in some places (many developing countries) but unexpectedly slowly in others (much of Europe). If the objective of sustainability is to ensure the maintenance of available resource levels on a per-capita basis, then complex and very different utilization rules will have to be adopted by rapidly and slowly growing societies. Furthermore, societies of either kind will have to make difficult decisions about what resource levels are adequate. If each member of a generation at time t uses substantially more water per capita than is needed for his or her basic needs, then is it reasonable for that society to decide on a future water allocation that meets all of everyone's needs but no more? Can it then claim that it has managed the resource sustainably?


Next, complicated issues of transgenerational equity emerge from other scenarios. Suppose that at some time t, average per-capita access to some resource is adequate. In the t + 1 generation, average per-capita access is increased. But members of the top third in t + 1 receive substantially more than before, whereas those in the bottom third get less, and for some of them the allocation falls below the level of essentiality. Could such a society claim that the resource has been treated sustainably? Perhaps it would assert that wise conservation has produced a sustainable resource improvement. But most would argue that the failure of the transformation to manage reallocation equitably leaves it short of achieving a sustainable outcome.

Finally, there are other social and cultural challenges to sustainability that relate to rates of historical change. For example, societies often become accustomed to positive improvements in average welfare and are likely to insist that the upward trajectory continue. Suppose that the renewal rate of some resource is slightly higher than that of population growth, so that the annual increase in welfare on a per-capita basis has been a consistently positive number. Would the sustainability criterion be met by simply guaranteeing that generation t + 1 has the same welfare as generation t, or will those in t + 1 feel as though they have lost?

These scenarios suggest a problem with the concept of sustainability, which turns out not to be just about resource use, efficiency of utilization, and conservation. Instead, the term carries with it strong social, economic, and cultural attributes. Different societies will therefore create their own definitions of sustainability and their own criteria for achieving it, and they are likely to set about the task in their own ways. Articles in Science's 2003 “State of the Planet” issues, now included in a book of the same title, have shown how small groups dependent on common-pool resources work out their own solutions and develop the means to enforce them.

Extending such successes to large-scale problems such as depletion of marine fisheries or global climate change is a difficult challenge. But more local successes have shown that social capital and broad participation in rule-making are important ingredients. In thinking about sustainability, prevailing economic, social, and ethical dimensions will be important factors in deciding what can work. Indeed, these are likely to dominate the technological aspects of resource management.

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