The time scale for new species adapted to a completely new climate is many millions of years, not a few thousands. What we destroy today won’t be replaced while humans as a species as we know it today even exists.
It will always be many orders of magnitude easier to terraform Earth, even after we screwed it up, than trying to terraform Mars.
It will always be many orders of magnitude easier to terraform Earth, even after we screwed it up, than trying to terraform Mars.