We must not be forced to explore the universe in search of a new home because we have made the Earth inhospitable, even uninhabitable.  For if we do not solve the environmental and related social problems that beset us on Earth – pollution, toxic contamination, resource depletion, prejudice, poverty, hunger – those problems will surely accompany us to other worlds.  ~Donald G. Kaufman and Cecilia M. Franz, Biosphere 2000:  Protecting Our Global Environment, 1996