You’re sitting there at home on Alpha Centauri Bb minding your own business when all of a sudden this warp ship shows up full of humans from Earth. Pretty soon you and your species are gone. Too bad for you, and your planet, but that’s progress.
Oh, but surely humanity will have learned better by then. Surely the prospect of billions of potentially habitable planets in the galaxy announced this week presages the glorious dawn of eternal human exploration and of cooperative inter-planetary development.
Tell that to the mastodons, and I don’t mean the ones at IPFW.
True, scientists are not sure that early humans trekking around the world wiped out most of the giant mammals. Maybe it was just a coincidence that the great creatures died out about the same time the humans arrived — again and again and again. But we know we are wiping out thousands of species of plants and animals every year right now and that we frequently even kill each other when we are in a bad mood.
Starships remain imaginary, but some people hope we can escape the mess we’ve made here by going somewhere else. And if we do escape, people wonder (see the accompanying covers from 2013 books at the library) whether there will be something on the far side to greet us. I suppose if other planets are just naked rocks, like Mars, then there will be no ecosystems for humans to despoil, but it seems likely that many of these planets will have water, and some of those will have complex life. Perhaps if humans ever do reach the stars, we will be so technologically advanced that we won’t need to exploit resources — living and non-living — as our ancestors always did. But our sheer desire to dominate may not have a technological fix.
Regardless of what humans may do elsewhere, however, the momentum to colonize other planets — which for now means only Mars — risks diverting attention from emergency measures to achieve a stable relationship between humans and the rest of life on the only planet we actually occupy. Besides, if we screw up Earth so badly that we can no longer support our technological civilization, other planets will remain forever beyond our grasp. If so, that will be lucky for them.