Today it could be argued that human beings daily act against our own self-interests. How? Biologist Paul Ehrlich and fellow scientists tell us we are expanding our population and economy beyond the Earth's carrying capacity - at our peril. Why do we insist on continuing? Ehrlich has been a keen observer of human behavior for over 50 years, and he thinks "we need a millennium assessment of human behavior." If we can understand how we behave, and why we behave that way, perhaps we can figure out how to behave as though we want to hang around another thousand years.
