It is obvious that if we want at least to halt the ongoing destruction of the biosphere, and then make steps toward renewing the harmony between human society and nature, we must first change our value structure. (Josef Vavrousek).
Because Homo sapiens is the dominant species on Earth, we and many others think that people have an absolute moral responsibility to protect what are our only known living companions in the universe. Human responsibility in this respect is deep, beyond measure, beyond conventional science for the moment, but urgent nonetheless. (Paul Ehrlich and Ed Wilson).