CNN needlessly asks:
The writer trades the value of having a “backup Earth” over the rights of any possible native Martian life (assumed to be bacterial at best) and comes down on the side of colonization. This is of course the correct answer, but the discussion leaves out the important detail that terraforming Mars might well be *better* for Martian life.
If there is any life on Mars today, it seems almost certain that that life is the tenacious last remnants of life that evolved a billion or more years ago when the planet was warmer and wetter. While life could well continue to survive in such a dried out frigid environment – just as life survives today in Antarctica – it has little future to evolve added complexity there. In short, life on Mars has gone as far as it’s going to. From here on out it’s a long slow fade to darkness.
But if mankind comes, sets up shop, parks some mirrors over the poles and starts dropping teratons of iceteroids, any existing Martian biota will see conditions that can only be considered “better.” And even if terraforming turns out to be bad for the Marsbugs, humanity will almost certainly preserve them in some way, and perhaps seed them somewhere else. If the bugs can survive on Mars, perhaps they could survive on Ganymede or Callisto and begin the terraforming process *there.* But regardless, the current crop of Marsbugs are going nowhere. They are more doomed than Earthly bunnies (who will not spread to the stars without the assistance of mankind).