Your objection to the Soviet Union boils down to the idea that it can't be considered a failure of socialism because it was a variant of  Marxism, and Marxism is not real socialism in any form.

Don't know what you mean by "Marxism" here.  It's hard for me to describe the Soviet Union as a "variant of Marxism" when I know that Marx predicted the rise of socialism "in the most advanced nations," and Russia ca. 1917 was hardly one of those.  Marx also had nothing to do with the "socialism in one nation" doctrine of Joseph Stalin.

Isn't there something a bit strange in so utterly rejecting Marx's vision while embracing his critique?

Was Marx supposed to have predicted global warming?  And is the labor theory of value supposed to lead automatically to Marx's endorsement of industrialism?

If you want to find it in Holy Writ, look up those passages in Engels' Dialectics of Nature where he suggests ending the division between countryside and city, because that's where all of this is leading.  

given the approach I don't see how it can possible be anything other than incoherent even if fleshed out.

I don't see how any constructive critique can be made out of your response.  You might try suggesting that I do something different.

Finally, like all expressions of radical environmentalism that I have ever seen, this one marries a radical environmental agenda with a radical sociopolitical one. Yes, I understand that for their proponents you can't have one without the other. Somehow it seems to have escaped them that all it does is make change even more unpalatable and more painful and difficult to implement; adding the massive upheaval of socio-political revolution to the wrenching changes required by the environmental constraints means all the more resistance and suffering.

Are you suggesting that world society shouldn't change its bad environmental behaviors?  Social change will be necessary to adapt to ecosystem change.

Given that, the fact that you've already taken the first big step down the Leninist path in point six doesn't bode well.

I really don't understand how anything I said is "Leninist" in any way, least of all in the doctrine of "democratic centralism" being repudiated here.

"Imagine all the people/ Sharing all the world" -- John Lennon