The piece even has the ridiculous title "Civilization's last chance," which, I don't know about you, but I kind of resent on behalf of my 3-yr old nephew and my 0.5-yr old niece.
He's even gone so far as to establish an organization -- another one, again -- calling for a 350 ppm CO2 atmosphere. It seems to already cover most of the green efforts on the planet and so, you can be sure, won't accomplish anything, except maybe sell a few more books.
McKibben bases all this on a recent paper -- which hasn't even yet cleared peer-review -- by Hansen, et. al., "Target atmospheric CO2: Where should humanity aim?", available on the ArXiv.
I read this paper last night and to me, an admitted non-expert, it seems to contain an awful lot of what physicists call "hand-waving arguments" -- semi-quantitative arguments that look more-or-less reasonable but which rapidly pile-up with a chain-link of uncertainites until you can't be sure of whether anything has been proven or not. There's very little rigor and no equation at all that says
disaster > 350 ppm
The 350 ppm level is "suggested," nothing more, which seems like very thin proof to base a reorganization of civilization on.
I might sign on for this, on the day McKibben demonstrates that he's willing to practice what he preaches -- live a life of about, what, 2 tC/yr? And I don't mean with carbon offsets, either -- trees die in 60-80 years and return all that sucked-up carbon to the atmo, just when we don't need it.
PS: I am sorry for being so flippant. It's just that changing some light bulbs and buying a Prius isn't going to cut it. Personally, I can't get much below 6 tC/yr. I doubt many others can either. Everyone else on the planet deserves to live at least as well as I do. That's going to require massive -- MASSIVE -- shifts in technology, in all sectors of life. Probably we can't do it. It will take decades if it is even possible. Asking for 350 ppm is simply a fantasy at this point, and fundamentally ignores reality.