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Ken Caldeira's Carbon Solution

There’s been a brouhaha over whether we “misrepresented” the research and views of the climate scientist Ken Caldeira, whom we write about in the global-warming chapter of SuperFreakonomics. We’ve been in constant touch with him over the past few weeks, since we wanted to amend future printings of our book if indeed there were misrepresentations. If you want to know the end of this story, just skip ahead to the bottom of this post. Otherwise, here’s the background:
Caldeira is working with Nathan Myhrvold and other scientists at the firm Intellectual Ventures on potential global-warming solutions, which include a variety of geoengineering ideas. We cite a variety of Caldeira’s research, primarily on atmospheric carbon dioxide, including these passages:

Caldeira is thoroughly convinced that human activity is responsible for some global warming and is more pessimistic than Myhrvold about how future climate will affect humankind. He believes “we are being incredibly foolish emitting carbon dioxide” as we currently do.


“Twenty thousand years ago,” Caldeira says, “carbon-dioxide levels were lower, sea level was lower — and trees were in a near state of asphyxiation for lack of carbon dioxide. There’s nothing special about today’s carbon-dioxide level, or today’s sea level, or today’s temperature. What damages us are rapid rates of change. Overall, more carbon dioxide is probably a good thing for the biosphere — it’s just that it’s increasing too fast.”


As much as Caldeira personally lives the green life — his Stanford office is cooled by a misting water chamber rather than air-conditioning — his research has found that planting trees in certain locations actually exacerbates warming because comparatively dark leaves absorb more incoming sunlight than, say, grassy plains, sandy deserts, or snow-covered expanses.

But as you can read here (if you really feel like going down a rabbit hole), it was the first sentence of the following paragraph that incurred the scorn of a climate blogger named Joseph Romm:

Yet his research tells him that carbon dioxide is not the right villain in this fight. For starters, as green house gases go, it’s not particularly efficient. “A doubling of carbon dioxide traps less than 2 percent of the outgoing radiation emitted by the earth,” he says. Furthermore, atmospheric carbon dioxide is governed by the law of diminishing returns: each gigaton added to the air has less radiative impact than the previous one.

A noisy conversation ensued, primarily in the climate blogosphere, and we were charged with gravely misrepresenting Caldeira’s views even though we sent him the manuscript for review before publication, and incorporated many of his additions and changes. (For the latest on this conversation, see here, here, or here.)
So what is Caldeira’s own position?
Here’s a block of text he sent me recently that he has labeled “Text Sent to Inquiring Journalists,” which he sends out when someone asks him about the “villain” issue:

Q: Romm says you objected to the “not the right villain” line but Levitt and Dubner left it in anyway. Is that accurate?
A: Reality is just slightly more complex.
I did receive a version in MSWord. I did not read it all but just searched for my name. (I feel no need to fact check things that come in over the transom.)
I highlit the offending sentence and wrote the following comment:
And yet his research tells him that carbon dioxide is not the right villain in this fight.[KC1]
[KC1]My views differ significantly from Lowell‘s and Nathan‘s. I do think we are being incredibly foolish emitting CO2 and that avoiding all of this environmental risk is a good way to invest a few percent of our GDP. My pessimism stems from the apparent difficulties of solving the “prisoner’s dilemma”- and “tragedy of the commons”-type aspects of this problem.
I expected, based on this comment, that the highlit sentence would be removed but did not explicitly request them to remove it. Instead, Levitt and Dubner added a line about “foolish” preceding the line that I was concerned about. So now the text reads:
He believes “we are being incredibly foolish emitting carbon dioxide” as we currently do. Yet his research tells him that carbon dioxide is not the right villain in this fight.
Did I object to the line? Arguably, yes. Was I clear and explicit about not wanting the line in there? No. Was there room for people acting in good faith to differ regarding what my highlighting meant? Yes.
All of the other statements attributed to me are based on fact, although there are differences in detail, nuance, etc.
As I have tried to say several times now: my views, beliefs, policy prescriptions, etc., differ from those of Myhrvold, Wood, Levitt, Dubner, etc., however, I do not question their good intentions.
I can and do frame my own beliefs differently and set them in a different context.

So, given all this drama, and how extensively Caldeira’s views and research figured in our global-warming chapter, we wrote to him and offered to change anything in the chapter in future printings if indeed we failed to portray his research and views accurately.
Here’s the only change he requested:

You could just change it to “However, carbon dioxide may not be the right villain in this fight” or something like that and not attribute it to me.

Sounds like a good solution. So that’s how future editions of SuperFreakonomics will read. Some critics may of course charge us with making this change only in order to make the first printing of the book more valuable and therefore drive sales. If only we’d been so clever on purpose …