ment that the future may hold (Chapter 4). In such analysis lies the prospect for informed investment in research, capacity building, action, and policy that can make more attractive the prospects for our common journey.
In the Board's judgment, a transition to sustainability over the next two generations should aim to meet the needs of a much larger but stabilizing human population, to sustain the life support systems of the planet, and to substantially reduce hunger and poverty. For each of these dimensions of a successful transition, there is wide international agreement about minimal goals and targets.
The current trends mentioned above are likely to persist well into the coming century and could significantly undermine the prospects for sustainability. If they do, we conclude that many human needs will not be met, life support systems will be dangerously degraded, and the numbers of hungry and poor will increase. Even the most alarming current trends, however, may experience transitions that enhance the prospects for sustainability. Based on our analysis of persistent trends and plausible futures, we believe that a successful transition toward sustainability is possible over the next two generations. This transition could be achieved without miraculous technologies or drastic transformations of human societies. What will be required, however, are significant advances in basic knowledge, in the social capacity and technological capabilities to utilize it, and in the political will to turn this knowledge and know-how into action.
The individual environmental problems that have occupied most of the world's attention to date are unlikely in themselves to prevent substantial progress in a transition toward sustainability over the next two generations. Over longer time periods, unmitigated expansion of even these individual problems could certainly pose serious threats to people and the planet's life support systems. Even more troubling in the medium term, however, are the environmental threats arising from multiple, cumulative, and interactive stresses and driven by a variety of human activities. These stresses or syndromes, which result in severe environmental degradation, can be difficult to untangle from one another and complex to manage. Though often aggravated by global changes, they are shaped by the physical, ecological, and social interactions at particular places, that is, locales or regions. Developing an integrated and place-based understanding of such threats and the options for dealing with them is a central challenge for the development of a useful ''sustainability science" for promoting a transition toward sustainability.
There are no maps for navigating a transition toward sustainability. Our common journey is nonetheless already under way. This Board's study has suggested the need for navigational strategies that can better