Oh it gets worse than that: we're in an interglacial period right now, coming out of an ice age.

When the Bering Strait ice bridge formed and the descendants of native peoples migrated down through the American continent, California was not a dry desert. It was probably covered by lush forests and wetlands with a much lower sea level than today so there's literally no way to return it to that "natural state"

With the Kelp highway hypothesis [1], humans were here for most of that transition so really there's a whole list of "natural states" to pick from (that we largely can't return to)

[1] https://en.wikipedia.org/wiki/Coastal_migration_(Americas)#K...

You're looking for rationality in an irrational position. These "preservationists" are really just environmental Catholics. Underneath the environmental rhetoric, they've internalized a version of original sin and desire to submit themselves to punishment for said sin. To suggest modern solutions and forward progress would be to suggest that the sinners could erase the original sin by sinning more.

To convince them to take action you have to validate their self-imposed guilt with images of reverting to noble savages clapping hands and playing pan-flutes around a fire while the animals sway in time to the music.

There was a time I would have said these people need education, now I'll settle for using their guilt to herd them in the correct direction.

One could argue that anything that ever happens is natural, since humans are part of nature.