We strive ever harder to realize the world of our deepest longings, only to find it receding further from our grasp, perhaps unconsciously counting on a crisis to wake us up. Our cultural history is a series of relatively calm periods punctuated with often-violent social change. We adjust to these altered conditions relatively quickly, as new generations replace those who were vanquished in the violent transitions from one order to another. Meanwhile, the natural world continues inexorably along its slowand steady evolutionary path, with little or no notice of the upheavals occurring in the human sphere. 

The world is different today. We have developed weapons of such power that humans no longer can recover their numbers so simply after these periodic hiccups of history. In addition, the rapid spread of modern technological, consumerist economies—a weapon of cultural, if not biological, mass destruction—is wiping out what little remains of cultures that once lived in harmony with the world and with themselves. – John R. Ehrenfeld Yale University