Yale Environment 360: I want to start with this little dust-up over SuperFreakonomics. In the book, you are quoted as saying, when it comes to global warming, “Carbon dioxide is not the right villain.” Is that accurate?

Ken Caldeira: That is not accurate. I don’t believe I said anything remotely like that because I believe that we should be outlawing the production of devices that emit carbon dioxide, and I don’t think we can solve this carbon climate problem unless we drastically reduce our carbon dioxide emissions very soon.

e360: They also write that you are convinced that human activity is responsible for “some” global warming. What does that mean?

Caldeira: I don’t think we can say with certainty whether we’re responsible for 90 percent of it or we might be responsible for 110 percent of it. But the vast majority of global warming, I believe, is due to human release of greenhouse gases to the atmosphere.

e360: Another thing that plays in to the same kind of sensibility is the idea [which the book quotes Caldeira saying] that the “doubling of CO2 traps less than 2 percent of the outgoing radiation emitted by the Earth.” When that’s phrased like that, it makes it sound like it’s not really much of a problem.

Caldeira: You should think of the whole global warming problem as a 1 percent problem, at least for doubling of CO2. In absolute temperature Kelvin — scientists like to use the Kelvin scale — the current Earth temperature is around 288 degrees Kelvin, and a 3-degree warming on top of that is basically a one-percent additional warming. And so this whole issue of climate change, when viewed from an Earth-system perspective, is a story about 1 percents and 2 percents. Two percent might sound like a small number, but that’s the difference between a much hotter world, and the kind of world we’re accustomed to….

e360: Overall, do you feel like your work has been accurately and fairly represented in this book?

Caldeira: The main misrepresentation is the quote that says that CO2 is not “the right villain.” Now, again, I don’t use “villain” talk myself, but if you say what’s the primary gas responsible for the planetary warming, I would say it’s carbon dioxide.

Now, there’s a tougher question when it comes to the other statements that are attributed to me. All of those other statements are based in fact and based on studies that either I have published or other scientists have published. And if we pull back to the case of the biosphere taking up 70 percent of CO2 — well, yes, we have a published study that said that. It also presented results saying that we might warm up the planet enough to risk melting Antarctica ultimately. And so there is a selective use of quotes.

If you spend several hours talking to somebody and they take a half-dozen things and put it in a book, then it’s going to be in the context and framing of arguments that the authors are trying to make. And so the actual statements attributed to me are based on fact, but the contexts and the framing of those issues are very different from the context and framing that I would put those same facts in…

So I think that the casual reader can … come up with a misimpression of what I believe and what I feel about things.

None of Caldeira’s statements in this recent Yale e360 interview are a surprise if you read my original, accurate debunking — Error-riddled ‘Superfreakonomics’: New book pushes global cooling myths, sheer illogic, and “patent nonsense” — and the primary climatologist it relies on, Ken Caldeira, says “it is an inaccurate portrayal of me” and “misleading” in “many” places.

And this all matches the Bloomberg interview of Dubner and Caldeira, which also backed up my reporting on error-riddled Superfreakonomics:

Caldeira, like the vast majority of climate scientists, believes cutting carbon dioxide and other greenhouse-gas emissions is our only real chance to avoid runaway climate change.

“Carbon dioxide is the right villain,” Caldeira wrote on his Web site in reply. He told Joe Romm, the respected climate blogger who broke the story, that he had objected to the “wrong villain” line but Dubner and Levitt didn’t correct it; instead, they added the “incredibly foolish” quote, a half step in the right direction. Caldeira gave the same account to me.

Levitt and Dubner do say that the book “overstates” Caldeira’s position. That’s a weasel word: The book claims the opposite of what Caldeira believes. Caldeira told me the book contains “many errors” in addition to the “major error” of misstating his scientific opinion on carbon dioxide’s role….

Although this made a lot of news, it really isn’t news.  Anyone who spends a great deal of time reading Caldeira’s work, communicating with and listening to him, as I have, would know instantly how directly at odds his views are with the entire Superfreakonomics chapter.

More newsworthy is Caldeira’s longer elaboration on his views of geoengineering and what the world’s overall approach to global warming should be:

e360: Let’s talk a little bit more broadly about geoengineering. I was struck by something one of the authors said on NPR the other day — that he got interested in geoengineering when he realized that the problem with global warming is not that there is too much carbon in the air; it’s that it is too hot. Do you agree with that?

Caldeira: The reason it is too hot is that there is too much carbon dioxide in the air. Now the carbon dioxide itself, of course, has big negative implications for ocean acidification and ecosystems, including coral reefs. So there are direct CO2 effects.

But I think if we had some magic thing that would reverse all effects of CO2 perfectly, then you could say, “Well the problem is not CO2.” But nobody re
ally expects that we are going to have some magic, perfect CO2 nullifier. And it’s clear to me that if we continue allowing greenhouse gas concentration to grow in the atmosphere, and try to engineer our climate to counteract those effects, that as the greenhouse gases accumulate, and our counteracting system grows ever larger and larger, that the risk of some kind of catastrophic failure of this offsetting — or the imperfections in this offsetting — would grow in time and the net result would be pretty negative, I would imagine.

So, I do see CO2 as the problem. I think to present it as if, “Well, it not’s really CO2, but the effects of CO2,” it’s like if you got shot by a bullet and you said, “Well, it wasn’t really the bullet that was the problem, it was just that I happened to have this hole through my body…”

e360: Right. Well, a lot of people think of geoengineering as a quick and cheap fix for global warming. Is it?

Caldeira: Let’s pretend for a moment that putting dust in the stratosphere is easy to do and works reasonably well. And let’s say the United States and England and the “Coalition of the Willing” decided to go ahead and deploy this system, and that China or India then went into a decade or two of deep drought. Whether the system caused that drought or not, I think the Chinese or the Indians would rightly suspect that the reason they have this drought and ensuing famines might be due to this system that was put up by these other countries. And you could easily imagine that there would be a great amount of political tension, and possibly even leading to warfare. So I think just the political dimensions and the governance dimensions of these geoengineering options suggest that we would be very reluctant to deploy these things, even if we thought they worked more or less perfectly.

Another example is that, in many climate model simulations, the area around Egypt tends to get wetter with global warming. And so what if you do this geoengineering scheme and it takes away water from countries that didn’t have water a few centuries ago? Are they are going to be happy you’re doing this? So I think just the political problems associated with perceived winners and losers are so great that a politician is not going to want to deal with these problems.

Then, of course, the system is not going to work perfectly. First of all, it’s not going to address the issues of ocean acidification. It’s not going to perfectly offset global warming, so you’ll have some residual effects. So, I look at these geoengineering options as something we would only want to consider if our backs were really up against the wall, and where all these environmental and political risks seem worth taking because the alternatives look so frightening.

e360: I know that some scientists have suggested that there should be some kind of taboo on geoengineering research. But I know that you’ve been outspoken in the need for a federally-funded geoengineering research program. Can you explain that?

Caldeira: Yes, I think we don’t know right now whether these kinds of approaches have the potential to reduce risk or not. In our climate models, the amount of climate change can be reduced by these kinds of approaches, but the climate models are an imperfect reflection of reality, and they don’t consider the kinds of political risks that I was mentioning before. And so I think we just have to say we don’t know whether these options can really reduce overall risk…

Let’s say geoengineering doesn’t work, and that it would add to risk. It seems to me it would be worth having a research program to demonstrate that beyond a reasonable doubt so we can all forget about this and move on.

On the other hand, if these options do have the potential to reduce risk, then it seems to me that we would like to have the option to reduce that risk should a time come where that would seem necessary. I kind of think of these geoengineering options as seeing, “Well, can we invent some kind of seatbelts for our climate system?” We need to drive the climate system carefully, we need to greatly reduce emissions. But even if we’re driving carefully we still run the risk of getting into an accident. And seatbelts can potentially reduce the damage when we’re in an accident.

But the reason I’m concerned about geoengineering is because I am so concerned about greenhouse gas emissions, and so, again, I’m in favor of essentially making greenhouse gas-emitting devices illegal. But I don’t think we’re going to reduce emissions fast enough to make me feel that we’re not running some really grave risks. And so I think we need to develop options to diminish those risks.

And it’s not just geoengineering. I’m much in favor of a very broad-spectrum approach. I think one of the things we saw with the subprime mortgage crisis is that a few million people in the United States defaulted on their mortgages and we have a worldwide economic crisis. I think we have to assume that climate change damage will be a much bigger amplitude than a few million mortgage defaults.

If there’s some kind of climate crisis in Southeast Asia, is that going to amplify and shake the whole global economic system? This is the kind of thing that Jim Lovelock is afraid of, that you’ll have “economic migrants” resulting from climate change that will ultimately destabilize modern civilization.

And so I think we also need to be doing research in how do we make our society more robust, so that these local climate damages won’t turn into global problems. We need to be doing basic adaptation planning; we need to look at geoengineering options. But the main thing we need to do is work to eliminate carbon dioxide emissions.

But thinking of geoengineering as a substitute for emissions reduction is analogous to saying, “Now that I’ve got the seatbelts on, I can’t just take my hands off the wheel and turn around and talk to people in the back seat.” It’s crazy.

The authors of SuperFreakonomics simply never understood what the chief climatologist they interviewed believed about the central thesis of their chapter, As Bloomberg reported last week:

Caldeira, who is researching the idea [of aerosol geoengineering], argues that it can succeed only if we first reduce emissions. Otherwise, he says, geoengineering can’t begin to cope with the collateral damage, such as acidic oceans killing off shellfish.

Levitt and Dubner ignore his view and champion his work as a permanent substitute for emissions cuts. When I told Dubner that Caldeira doesn’t believe geoengineering can work without cutting emissions, he was baffled. “I don’t understand how that could be,” he said. In other words, the Freakonomics guys just flunked climate science.

And ironically, the “polymath’s polymath” contrarian’s contrarian apparently agrees with Caldeira in opposing the geoengineering-only approach — although Nathan Myhrvold apparently never understood what the Superfreaks actually wrote in their chapter and the Superfreaks apparently never understood what the former Microsoft CTO actually believed!  See Nathan Myhrvold jumps the shark — and jumps ship on Levitt and Dubner (on their blog!) asserting: “Geoengineering is proposed only as a last resort to try to reduce or cope with the even greater harms of global warming! … The point of the chapter in SuperFreakonomics is that geoengineering might be good insurance in case we don’t get global warming under control.” Did he even read the book?

One final quote that I think might surprise a great many people who don’t know Caldeira, who got their entire misimpression of him from Superfreakonomics:

If I had to wager, I would wager that we would never deploy any geoengineering system….

If you want to know what Caldeira thinks will happen, you can listen to Caldeira’s entire interview with journalist Jeff Goodell on the Yale e360 website.

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