The greenhouse effect is a more apt name than those who coined it imagined. The carbon dioxide and trace gases act like the panes of glass on a green… - Bill McKibben

They'll lead us bit by bit toward the revolutionary idea that we've grown about as powerful as it's wise to grow; that the rush of technological innovation that's marked the last five hundred years can finally slow, and spread out to water the whole delta of human possibility. But those decisions will only emerge if people understand the time for what it is: the moment when we stand precariously on the sharp ridge between the human past and the posthuman future, the moment when meaning might evaporate in a tangle of genes or chips.

Human beings—any one of us, and our species as a whole—are not all-important, not at the center of the world. That is the one essential piece of information, the one great secret, offered by any encounter with the woods or the mountains or the ocean or any wilderness or chunk of nature or patch of night sky.

The expected effects of a sea-level rise typify the many consequences of a global warming. On the one hand, they are so big we literally can't understand them. If there is a significant polar melting, the Earth's center of gravity will shift, tipping the globe in such a way that the sea level might actually drop at Cape Horn and along the coast of Iceland—I read this in a recent EPA report and found that I didn't really understand what it meant to tip the Earth, through I was awed by the idea. On the other hand, the changes ultimately acquire a quite personal dimension: Should I put in a wall in front of my house? Does this taste salty to you? And, most telling of all, the human response to the problems, the utterly natural human attempt to preserve the old natural way of life in this postnatural world, creates entirely new consequences. The ocean rises; I build a wall; the marsh dies, and, with it, the fish.