So why not right now then? What number of years or days or hours would concern you? Are you not concerned about other life besides human life on Earth?
Of course, I want to protect nonhuman life with all my heart. I just don't think it's a big deal if humans go extinct in some thousands or millions of years. I feel much differently about nonhuman life. From the perspective of nonhuman life, we are a disease.
If we're a disease, don't you want to exterminate us?
But then, if all other life is so much better than human life, and if by adding 220ppm of CO2 we extended the time left for that life on Earth by a few million years, didn't our intervention save non-human life from a worse fate[0] than merely having to deal with us? So we can be both, disease and cure.
[0] All life on Earth will go extinct eventually, but if we've added a few million years to its story so far, and we could add more millions later, then maybe saying we've "saved" that life is fair.
