Too many rich people in the world is a major threat to the human future, and cultural and genetic diversity are great human resources. - Paul R. Ehrlich

Few problems are less recognized, but more important than, the accelerating disappearance of the earth's biological resources. In pushing other species to extinction, humanity is busy sawing off the limb on which it is perched.

Interstellar transport for surplus people presents an musing perspective. Since the ships would take generations to reach most stars, the only people who could be transported would be those willing to exercise strict birth control. Population explosions on space ships would be disastrous. Thus we would have to export our responsible people, leaving the irresponsible at home on Earth to breed.

Life has now entered a . This is probably the most serious environmental problem, because the loss of a species is permanent, each of them playing a greater or lesser role in the living systems on which we all depend . The species extinctions that define the current crisis are, in turn, based on the massive disappearance of their component populations, mostly since the 1800s. The massive losses that we are experiencing are being caused, directly or indirectly, by the activities of Homo sapiens. They have almost all occurred since our ancestors developed agriculture, some 11,000 y ago. At that time, we numbered about 1 million people worldwide; now there are 7.7 billion of us, and our numbers are still rapidly growing. As our numbers have grown, humanity has come to pose an unprecedented threat to the vast majority of its living companions.