Earlier quoted context omitted.
In that sense then the term "terraforming" is on equal footing with alchemy.
Doing something like that at planetary scale is science fiction anyway even if we did have the tech to do it.
We have converted most of the land to agriculture and released maybe trillions of tons of greenhouse gas in the atmosphere, there are 8 billions of us working on it. And what did we do? Increased the global temperature 2 degrees? Made the sea level rise a couple of meters?
It may be bad for us, but compared to terraforming a planet like Mars, that's nothing, and we have the entire humanity industrial complex to do it while on mars, we need to build everything, starting from a hostile environment.