Pale Blue Dot - Carl Sagan [124]
IF THERE WERE A COMPELLING REASON for terraforming other worlds, this greatest of engineering projects might be feasible on the timescale we’ve been describing—certainly for asteroids, possibly for Mars, Titan, and other moons of the outer planets, and probably not for Venus. Pollack and I recognized that there are those who feel a powerful attraction to the idea of rendering other worlds in the Solar System suitable for human habitation—in establishing observatories, exploratory bases, communities, and homesteads there. Because of its pioneering history, this may be a particularly natural and attractive idea in the United States.
In any case, massive alteration of the environments of other worlds can be done competently and responsibly only when we have a much better understanding of those worlds than is available today. Advocates of terraforming must first become advocates of the long-term and thorough scientific exploration of other worlds.
Perhaps when we really understand the difficulties of terraforming, the costs or the environmental penalties will prove too steep, and we will lower our sights to domed or subsurface cities or other local, closed ecological systems, greatly improved versions of Biosphere II, on other worlds. Perhaps we will abandon the dream of converting the surfaces of other worlds to something approaching the Earth’s. Or perhaps there are much more elegant, cost-effective, and environmentally responsible ways of terraforming that we have not yet imagined.
But if we are seriously to pursue the matter, certain questions ought to be asked: Given that any terraforming scheme entails a balance of benefits against costs, how certain must we be that key scientific information will not thereby be destroyed before proceeding? How much understanding of the world in question do we need before planetary engineering can be relied upon to produce the desired end state? Can we guarantee a long-term human commitment to maintain and replenish an engineered world, when human political institutions are so short-lived? If a world is even conceivably inhabited—perhaps only by microorganisms—do humans have a right to alter it? What is our responsibility to preserve the worlds of the Solar System in their present wilderness states for future generations—who may contemplate uses that today we are too ignorant to foresee? These questions may perhaps be encapsulated into a final question: Can we, who have made such a mess of this world, be trusted with others?
It is just conceivable that some of the techniques that might eventually terraform other worlds might be applied to ameliorate the damage we have done to this one. Considering the relative urgencies, a useful indication of when the human species is ready to consider terraforming seriously is when we have put our own world right. We can consider it a test of the depth of our understanding and our commitment. The first step in engineering the Solar System is to guarantee the habitability of the Earth.
Then we’ll be ready to spread out to asteroids, comets, Mars, the moons of the outer Solar System, and beyond. Jack Williamson’s prediction that this will begin to come about by the twenty-second century may not be far off the mark.
THE NOTION OF OUR DESCENDANTS living and working on other worlds, and even moving some of them around for their convenience, seems the most extravagant science fiction. Be realistic, a voice inside my head counsels. But this is realistic. We’re on the cusp of the technology, near the midpoint between impossible and routine. It’s easy to be conflicted about it. If we don’t do something