Well, as have been said over and over… we need our planet, our planet does not need us. If we make it unfit for humans to live on, our race will be simply be replaced by some other living form. Even if we manage to come out from Earth and colonize some other place in the solar system, those places will be dependant on Earth for looong time.
Many precious speechs have been spoken, many will be. I’ve selected a couple.