Monday, May 12, 2008

350 ppm

Bill McKibben has a piece in the LA Times saying that we need to cut our atmospheric CO2 level to 350 ppm or, really -- really, this time I mean it, I really really mean it -- civilization is going to end at 5:12 pm on May 27th.

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.


Jon Lebkowsky said...

So, David, I read your final paragraph, and I want to be clear about this... you're saying that the real issue is not whether the 350 ppm supposed limit is accurate, but that it's an impossible target, because we can't change our baseline standard of living? And the other billions of humans in the world are entitled to that same baseline standard? And if the results may be catastrophic, so be it?

I think that's really the point of the call to action around the number 350: setting a target helps make the point in a way that really sticks, hopefully sinks in. And it doesn't have to be about a lower standard of living: as my Worldchanging colleagues have pointed out, over and over - this is really an opportunity to reinvent processes and economies so that we reduce our carbon footprint to zero, perhaps evolve other forms of mitigation, while retaining a reasonable to high SOL. McKibben comes down, arguably, a little too heavy on the regulation side - but you can see this as a call for solutions, and not necessarily as a call for regulation.

Dano said...


your argument is like saying that because the experts say we should save 10% of our salary, and most Murricans aren't doing it, therefore we should just not save.

The 10%, as Jon wrote above, is a target. Future investment needs something to shoot for, technology needs something to aim for (that 'massive technology' you like) - tech advances happen because folk are trying to do something.

The point is, BAU means "hard landing". Change means "soft landing". The bigger the change the bigger the pillow to land on.

Just because most people are lazy and resistant to change doesn't mean we do nothing.



David Appell said...

Jon: my answer to you is basically "yes." I don't think society can reach a 350 ppm atmosphere -- even if we could somehow lead a carbon-free life -- a HUGE transition in civilization -- there are still land-use changes to cope with. We will have upwards of 10B people on the planet soon -- I don't see how we can raise enough food and still reduce carbon emissions from land use changes.'

I'm not presenting a detailed calculation. I just can't see a net-zero C society in anything less than 100 years. People will burn whatever they need to stay alive, regardless of the consequences to the planet.