Briefly, humanity has overshot the limits of what is physically and biologically sustainable. That overshoot WILL lead to the collapse of the planetary environmentÕs ability to support not only our species but much of the rest of the biosphere if we do not act rapidly and effectively to reduce our footprint. These conclusions provide reasons for both optimism and alarm: optimism because humanity has demonstrated its capacity to act appropriately in one specific instance; and alarm because thirty years have been largely wasted since the consequences of our failing to act were detailed. There is still time but the need to act quickly and effectively is urgent. The authors demonstrate that the most critical areas needing immediate attention are: population; wasteful, inefficient growth; and pollution. They show how attention to all three simultaneously can result in returning the human footprint on the environment to manageable, sustainable size, while sharply reducing the disparity between human well-being and fostering a generous quality-of-life worldwide. Absent this, the prospects are grim indeed.
The book is divided into three sections, the first outlining in principle the authorsåÕ systems analytical approach to understanding the planet’s ecology. Their presentation is clear and comprehensible with an abundance of charts and figures that make visualizing the concepts easy. They successfully avoid the pitfalls of many technical presentations by using familiar analogies and largely avoiding professional jargon. As a result readers come away with insights not just into global interconnectedness of inputs, outputs, accumulation and feedback but also the significance of such dynamics in local, even personal, situations.
The second section deals with the authorsåÕ updated and revised modeling program, World3, which they utilize to test the plausible effects of changes in human political, economic and social behavior on the environment. Their discussion of World3 focuse