I had been seeing signs of progress from Andy Revkin, but the scratched side of the coin came up this week. Check this article.
Now I want to say that critics of science ask good questions, even though they tend not to listen to the answers. Revkin kicks off by quoting Larry Griesel (apparently disgruntled by the whole climate question) asking for quantification:
I would encourage Mr. Revkin to post a Dot Earth blog entry in which he QUANTIFIES the following:This begins with the not uncommon confusion is the idea that the amount of greenhouse gases in the air is a quantity not under conscious control. What will be depends crucially on what we do. (Think of Scrooge's question to the Ghost.)
1) “A big buildup of greenhouse gasses”: Please restate, in ppm of atmospheric CO2.
2) “A long-lasting and very disruptive shift”: Please specify the exact nature of the one or two most-serious disruptive shifts, and QUANTIFY the minimum degree of this risk. For example, if the “disruptive shift” is future flooding and droughts, specify the predicted annual agricultural output in the period following this “disruptive shift”. “Long-lasting” to be quantified in number of decades.
3) “RISKS”. For each most-serious disruptive shift specified in (2), state the probability of this shift, as a range. For example: Probability range = 0.1 to 0.5. Or, probability range = 0.01 to 0.10.
4) Present the “consensus climate science” that substantiates the RISK probability range specified in (3), to the 80% confidence level. Presumably this consensus climate science is available in an IPCC publication.
But these questions can be answered quantitatively as a function of emissions trajectory, and the uncertainties only get severe as the outcomes get severe. I think it's worth giving it a try. And indeed,
a team (including In It reader Jim Bouldin) Vince Gutschick takes a shot at it in Revkin's article.
And here is where things get weird. The group concludes:
The most extreme risk envisioned in all climate studies is surely a runaway greenhouse effect, in which human activities cause a buildup of CO2 to a level (ca. 1400 ppm). In this condition, as hot as it would be and as much as the patterns of precipitation and other processes have been altered, large additional rises are unstoppable. Natural processes release massive amounts of CO2. Some are biological, such as rapid respiration of vast stores of organic carbon in soils globally by bacteria, activated by high temperature. Others are a-biological, such as ocean degassing from the lower solubility of CO2 in warm versus cool water and also melting of methane clathrates (ice with trapped methane, which is more potent than CO2 as a greenhouse gas. There is good evidence of past runaway greenhouse events. One or more ensued as the recovery from Snowball Earth episodes (a fascinating story, but there is no room to detail this here). Another is themid-Cretaceous period, when CO2 has been inferred to be as high as 3000 ppm (very indirect evidence, such as from the structures of plant leaves). Ocean temperatures as high as 38 C (100 F) are inferred. This level would be lethal to us; dinosaurs prospered in what Richard Alley from Penn State has called the “Saurian Sauna.”OK, that is some scary stuff. It's not "runaway" as on Venus; the ocean does not boil off, but geochemical feedbacks act to take us into territory far beyond normal, far beyond what complex terrestrial life can handle.
Basically, anything that can't survive in a zoo is doomed in that scenario. If civilization survives through something like that, the only silver lining is that it will be great for space colonization, there being no particular advantage to the Earth over other planets.
This is at 5x background CO2 + CO2-equivalent. That won't happen overnight, but it isn't outside the realm of the possible if people continue to make a religious issue out of not accounting for externalities.
That's weird enough. I mean, how scary do things have to get. But that's not the weird part of the article.
Revkin doesn't question this terrifying scenario at all. But he throws in a pitch for Pielkian insouciance anyway. He can't resist.(Lest I be misunderstood, Yohe is not the one talking runaway. That isn't the point, really.)
"(For what it’s worth, I agree with Yohe’s assessment, although I differ with his preference for a rising price on carbon as the most feasible way to develop an energy menu that works for the long haul.) "
The point is, how strong is the compulsion to be "reasonable" and "centrist" and "opposed to draconian taxes" in the face of the literal destruction of the world!
I'm not saying I think the total destruction of the world is on the table. I am resisting believing that. It's probably my own coping mechanism.
Revkin, however, is quoting people saying that the destruction of the world is on the table, and isn't calling that into question. He just doesn't think that an outcome like that is serious enough to try raising taxes.
The evidence is piling up that our circumstances are beyond our cognitive or managerial abilities. I'm more scared of that than of hundred degree oceans right now. I think at the present rate we will not manage to maintain what we are pleased to call civilization long enough to get to 5xCO2. I suppose you could say that may be more good news than bad news; at least a few vertebrates will straggle through.
Note: Attribution in part to Jim Bouldin above was incorrect. The error followed Revkin's erroneous attribution. Jim corrected this and in fact replied in a very scientifically conservative and unimpeachable way which you can now see at the referenced article.