We do not need to save the Earth, it will be fine without us.  We cannot preserve the ecosystem because there are many, and they are constantly changing.  There has never been a time or a condition of the planet that has been inherently superior to any other.  There is nothing particularly superior about organisms that have been here for centuries, over ones that have just arrived from Asia in cargo holds.  All existing species are successful invasive species.  We are fairly successful, but far less so than cockroaches.  Most of the organisms that have ever been alive are dead, and their kind extinct.

We need to get rid of sanctimonious claims that Earth is our mother and we must nurture her.  Earth does not care whether we die out or not; it would be just fine as an iceball again.  Mars is not dead, and does not need to be revived.

The only entities to whom our continued existence as a species matters are ourselves, and possibly our dogs.  Certainly not our cats, still less our goldfish.

We need to get over the idea that we are harming nature.  We are nature.  Everything we do is natural, even if it leads to results unfavorable to ourselves.  We need to stop thinking in terms of preserving a sacred other, and realize that what we must do is keep the Earth suitable for ourselves to continue to live on.  That’s it, no holy quest, just pure self interest.  It’s something we’re rather good at.

Even then, if we are wildly successful, our species will no longer exist in a few million years, just as our Australopithecine ancestors no longer exist as a species.

Moral imperatives can be successfully refuted by mere denial; solid arguments based on evidence of our pure self interest are much more difficult to refute.  That’s just the way things are.