Our Unique Spaceship Earth
The concept of Spaceship Earth reminds us this simple fact that we all live aboard the same spaceship. Until proven wrong, there's only one Earth that we have access to, and that can sustain life. As rational living entities bound to Earth, we should therefore be careful not to make it inhospitable for our own survival.
 Snippets from the Wikipedia Article
Spaceship Earth is a world view term usually expressing concern over the use of limited resources available on Earth and the behavior of everyone on it to act as a harmonious crew working toward the greater good.
The earliest known use is a passage in Henry George's best known work, Progress and Poverty (1879). From book IV, chapter 2:
It is a well-provisioned ship, this on which we sail through space. If the bread and beef above decks seem to grow scarce, we but open a hatch and there is a new supply, of which before we never dreamed. And very great command over the services of others comes to those who as the hatches are opened are permitted to say, "This is mine!"
On July 9, 1965, in Geneva, Switzerland, Adlai Stevenson made a famous speech to the Economic and Social Council of the United Nations in which he said:
We travel together, passengers on a little space ship, dependent on its vulnerable reserves of air and soil; all committed for our safety to its security and peace; preserved from annihilation only by the care, the work, and, I will say, the love we give our fragile craft. We cannot maintain it half fortunate, half miserable, half confident, half despairing, half slave—to the ancient enemies of man—half free in a liberation of resources undreamed of until this day. No craft, no crew can travel safely with such vast contradictions. On their resolution depends the survival of us all.
The phrase was also popularized by Buckminster Fuller, who published a book in 1968 under the title of Operating Manual for Spaceship Earth. The quotation is from Section 8: The regenerative landscape. This quotation, referring to fossil fuels, reflects his approach:
"...we can make all of humanity successful through science's world-engulfing industrial evolution provided that we are not so foolish as to continue to exhaust in a split second of astronomical history the orderly energy savings of billions of years' energy conservation aboard our Spaceship Earth. These energy savings have been put into our Spaceship's life-regeneration-guaranteeing bank account for use only in self-starter functions."