Energy and Sustainability

![Figure][1] The theme for the 2007 annual meeting of the AAAS, to be held in San Francisco on 15 to 19 February, is “Science and Technology for Sustainable Well-Being.” The problem of energy, which is the focus of this special issue of Science linked to the meeting, looms as a central element in the web of intertwined challenges that this theme embodies. Well-being has environmental, sociopolitical, and cultural dimensions as well as economic ones, and the goal of sustainable well-being entails improving all of these dimensions in ways and to end points that are consistent with maintaining the improvements indefinitely. This challenge includes not only improving sustainably the standard of living in developing countries, but also converting to a sustainable basis the currently unsustainable practices supporting the standard of living in industrialized ones. Civilization's ability to meet this immense challenge clearly depends on our strengths in natural science and engineering. But it also depends on our strengths in the social sciences and in “social technology” in the form of business, government, and law, as well as on the societal wit and will to integrate all of these elements in pursuit of the sustainable-well-being goal. ![Figure][1] CREDIT: JUPITER IMAGES No part of this challenge is more complex or more demanding than its energy dimension. This is so in part because energy supply is tightly intertwined with national and international security and with many of the most damaging and dangerous environmental problems—from indoor air quality to global climate change—as well as with the capacity to meet basic human needs and fuel economic growth. The multiplicity and importance of these linkages would make energy a vexing issue even in a world where energy demand was constant. But that is not the world we live in. Continuing population growth and rapidly rising affluence in many parts of the globe are driving a rate of increase in energy use that has staggering implications. Even if the energy efficiency of the world economy—gross world product per unit of energy—were to continue to increase at the long-term historical rate of about 1% per year, the realization of middle-of-the-road population and economic projections would entail quadrupling world energy use in this century. In a world where today one-third of primary energy comes from oil (two-thirds of the remaining high-quality supplies of which probably lie under the volatile Middle East) and 80% comes from oil, coal, and natural gas combined (virtually all of the carbon dioxide from the combustion of which continues to go straight into the atmosphere), that middle-of-the-road energy trajectory cannot be managed simply by expanding what we are already doing. Such a path is not merely unsustainable; it is a prescription for disaster. The perils of oil dependence and climate change, coupled with the demand for large increases in the per-capita availability of energy services, compel an early transition to a different path. Its requirements include a reduction in global population growth (achievable, fortunately, by means that are desirable in their own right) and a sharply increased emphasis on improving the efficiency of energy conversion and end use (aiming to improve the energy efficiency of the world economy not by 1% per year but by 2% per year or more). Also required is a several fold increase in public and private investments to improve the technologies of energy supply. We need to know whether and how the carbon dioxide from fossil-fuel use can be affordably and reliably sequestered away from the atmosphere; whether and how nuclear energy can be made safe enough and proliferation-resistant enough to be substantially expanded worldwide; and to what extent biofuel production can be increased without intolerable impacts on food supply or ecosystem services. And we need to improve the affordability of the direct harnessing of sunlight for society's energy needs. Much insight about the current prospects in these and other dimensions of the energy problem is available in this special issue of Science. Still more about energy is on the agenda for the San Francisco meeting, along with much else germane to “Science and Technology for Sustainable Well-Being.” I commend it all to your attention. Nothing is more important to the human condition in the 21st century than rising to this set of challenges. [1]: pending:yes