Geoengineering to Have Its Day in the Sun

Most readers of this blog are probably aware of the tit-for-tat between us and some critics of our global-warming chapter in SuperFreakonomics. In the larger scheme of things the dispute is practically meaningless, at best a very distant second to the actual climate issues on the table.

To that end, the best news I’ve heard recently is that Congress will next week hold its first-ever hearing on geoengineering solutions to global warming. I’m grateful to Ken Caldeira for alerting us to this hearing; he will be among the climate scientists to testify.

While there is a lot of room for a lot of legitimate debate about many aspects of global warming, let us say one thing here: we believe that anyone who reads our chapter without an agenda wouldn’t even find it particularly controversial. They will see that we routinely address the concerns that critics accuse us of ignoring (the problem of ocean acidification, e.g., — touched upon in the previous chapter — and the “excuse to pollute” that geoengineering solutions might afford), and that we neither “misrepresent” climate scientists nor flub the facts.

The attacks have been noisy, as is now the backlash. In recent days, the Wall Street Journal, Los Angeles Times, and even Jon Stewart have jumped in to defend what we wrote. USA Today also published our op-ed on the topic.

It seems the global-warming rhetoric is cooling. The Union of Concerned Scientists, for instance, seems to no longer think that we are quite so daft. Levitt and I recently spent a day in Washington talking about the book. During an interview on the Diane Rehm Show (with Terry Smith filling in), we spoke with Dr. Peter Frumhoff, the U.C.S.’s director of Science and Policy. It was a productive and civil discussion. Later in the evening, we had a talk/book signing at the Washington Post Conference Center. During the Q&A session, Aaron Huertas, a press secretary for the U.C.S., took the microphone. (The Union of UnConcerned Scientists, predictably, were a no-show.) Huertas said he liked what he heard about global warming during our lecture and interviews and that he looked forward to keeping the dialogue going. The next morning, Huertas posted a similar comment on the Journal editorial, while again calling for further discussion.

We’d love the discussion to continue! That’s the point of our chapter: to show that the current proposed path for dealing with global warming is inadequate, and to explore better solutions. I know that congressional hearings are often better known for drama than for science, but here’s hoping that the upcoming geoengineering discussions will throw some bright light on this topic.

Point of View

A pessimist says that the glass is half empty.

An optomist says that the glass is half full.

An engineer says that the glass is too big.

A Geo-engineer pumps the water full of C02, sells it in recyclable glass bottles, retires, and takes up organic farming.

Bart Simpsons

I just read your book, and was expecting the chapter on geoengineering to show off the law of how a professors competence falls of with the square of the distance of his own topic, but I found it a quite good read. I'd just like to point out that by saying that mankind only contributes 2 % of the annual output of CO2 is a misleading statement, since it is the net addition that counts, and there mankind is way up.

Thanks for a good read!

Ben D

What, exactly, is "the current proposed path for dealing with global warming?"


The world is engaging in trading and production processes and procedures that have led to an extremely large externality to deal with, global warming. Simplifying the law of thermodynamics and laws of conservation of mass, stuff cannot be destroyed or gotten rid off. This has left us an enormous task of "cleaning up" our Earth. We have to "reverse pump" all toxic pollutants into some sort of nonhazardous product, while consuming energy in the process. First such process of consuming energy without damaging the environment needs to be discovered or invented for us to accomplish such goal.

A way to prevent environmental catastrophes would be to live off interest, meaning to live off what the core of something produces, without risk of the core ever running out. For example, use wood from trees that grow outside a certain forest perimeter. This, of course, would greatly slow down economic growth, but significantly contribute to the effort against global warming. Its up to the human intellect if a system to control global warming is developed before we must resort to living off interest of resources.



It scares me that none of this stuff had broken into the mainstream discussion prior to the book. There's this CO2 glass ceiling that had to be broken. Thank you.


I haven't had a chance to purchase/read the book yet (I will, I will) so I'll apologize if I'm going over something that's been covered. What about the law of unintended consequences? I'm all for researching and exploring geoengineering , especially if a catastrophe scenario has a legitimate possibility but it seems like this type of thing could cause many an unexpected problem. The best example I could think of (and I'll grant this is generally not nearly as sophisticated) is when a non-native species is introduced to control over-breeding. I wouldn't say all of those backfire but I've never heard of a successful example. Do they build this risk into the cost benefit analysis? I don't necessarily expect a response but if there's a Q & A I'd appreciate if some version of this question could be presented. Appreciate the work.


Does this book have any other chapters?


I read "SuperFreakonomics" while running from the Denver snowstorm. Interesting in the discussion of walking vs. driving drunk the subject of relative mileage walked to mileage driven never comes up but later in the book, you fastidiously mention that far more miles are driven today than 40 years ago in the discussion of seat belt safety.... But I digress. The chapter on global warming: Excellently written; however, I'd like to point out that the automobile was an accidental solution to the problem of horse manure in cities. There is no guarantee that any of these solutions you mention will work - I hope they do. I didn't read the words of climate change deniers; however, I did read a technological optimism I can only very cautiously share. We found a way out of the horseshit around the turn of the century but I don't think our leaders ever will, nor will the common man who is far more concerned with having enough money to pay off their mastercard bill than in how hot the midwest will be in fifty years. Not to mention the flatulence that passes for debate in 21st Century America - were that real rather than metaphoric, the surface of our planet would more closely resemble Venus than any other planet in the solar system.



"While there is a lot of room for a lot of legitimate debate about many aspects of global warming, let us say one thing here: we believe that anyone who reads our chapter without an agenda wouldn't even find it particularly controversial."

Right. Because being controversial was the furthest thing from your minds.

(rolls eyes)


The WSJ article you link to is "jumping in to defend what you wrote"? Have you read it? An article that compares Marxism to global warming is a worthwhile validation of your book?


I just finished the book today and glad I didn't skip ahead to the global warming chapter. I thought it was well presented and thought provoking. I have mostly ignored the flat-earthers who don't believe in man-made global warming as most of them are coming from 'God would never let us destroy his creation'. You boys have done a good job of contributing to the conversation and done so in a civil, professional, intelligent if we can just get most of our leaders to do the same.

The geo-engineering balloon is a great idea that needs to be explored. The one question I had about the the 34 lbs of sulfur dioxide that would be pumped: How evenly would it be dispersed and how quickly? The 'pipe' of a volcano plume is a lot bigger than what is being suggested, but then maybe IV has incorporated this into their model.

Matt Andrews

You claim that "we routinely address the concerns that critics accuse us of ignoring [...] the problem of ocean acidification".

Could you clarify? With some kind of specific quote, for instance? Because, y'know, there's nothing I can see in the book that even remotely "addresses" it.

Ocean acidicifcation is one of several fundamental flaws with the sulphur aerosol techno-fix. Flaws that you would have discovered very quickly, had you actually researched the issue.

Seems to me this ThingsBreak piece is summarising the situation quite aptly at the moment.


Here is everything your chapter 5 says about ocean acidification:

[Caldeira] and a co-author coined the phrase 'ocean acidification.' the process by which the seas absorb so much carbon dioxide that corals and other shallow-water organisms are threatened.


It seems there is a little dissent about the science on solar cells and other things in the chapter:

All good publicity in the end, no doubt?


Obviously, geoengineering needs to be assessed and studied. We may very well need to pump sulfates high into the atmosphere to slow global warming.

My impression, though, is that the science in the chapter is just plain sloppy and somewhat misleading, and lacks the intellectual rigor I'd expect from the the two of you (I have a master's degree in climate science, so I know the topic well). It's not an issue of bias -- it's more of an issue of how the numbers are presented.

For instance, how do you respond to this?:

I mean, don't you honestly think you misrepresent these numbers?

If you own up to misrepresenting these facts, it doesn't mean you have to abandon the idea that geoengineering may work, or that you think it could be cost effective. (You've already succeeded greatly in drawing attention to this possible solution). But your sloppiness in the chapter really requires some explaining -- otherwise, how can we trust the rest of your research?


Ben Kalafut

Ray Pierrehumbert crunches some numbers here and makes a pretty convincing case that you flubbed something. At this point there's no harm in admitting that you guys goofed up a bit. The ensuing discussion has actually been constructive.



'The WSJ article you link to is "jumping in to defend what you wrote"? Have you read it? An article that compares Marxism to global warming is a worthwhile validation of your book?'

I'm sure Dubner has read it. That's one of the two themes of the chapter: One is to promote geoengineering, the other is to argue that the scientific consensus on global warming is rigidly ideological (they prefer the metaphor of "religious", but "Marxist" carries the same general connotation in this context). To be clear, it's not that Levitt and Dubner argue that humanity is definitely not responsible for the increase in CO2 and temperature or that the trends will continue. They just (mostly implicitly) dispute what they see as the excessive confidence of most climate scientists on this.

Aaron Huertas

Thanks for this post, Mr. Dubner.

We here at UCS appreciated your willingness to engage with a scientific critic. During the interview, Levitt quoted others saying geoengineering is a solution to global warming like "methadone is to a heroin addiction." He added, "You won't be able to stop this if you don't deal with the carbon issue."

At the talk Mr. Dubner references, I thanked both authors for clarifying their views on geoengineering earlier that day with Dr. Furmhoff. I also urged them to clarify the scientific claims in the book that have been criticized by UCS and independent climate scientists. Mr. Dubner said they will respond to these scientific criticisms. Having a productive dialogue about the book is predicated on addressing those criticisms and accurately communicating climate science.

On the substance of the book and how it presents the scientific facts of climate change, UCS stands by the criticisms it has expressed. Our organization also shares the mainstream scientific view that swift, deep heat-trapping emissions reductions are necessary to avoid the worst consequences of climate change.

Aaron Huertas
Union of Concerned Scientists



Re. poster #5, saying "It scares me that none of this stuff had broken into the mainstream discussion prior to the book."

There's been at least some attention, but I agree that it hasn't been promoted as a solution. The 4th IPCC report, representing a fairly-up-to-date consensus on the climate, for instance, says that geoengineering "needs study" and that while we could cool the planet, "there are also risks and this approach will not mitigate or address other effects, such as increasing ocean acidification."

So, the reason that there hasn't been much attention in the general media seems to be because the response from the experts has been unenthusiastic. The IPCC report only devotes a few pages to changing the amount of sunlight, compared to the hundreds it devotes to ways to reduce greenhouse gases.

I'm of the opinion that there's a reason for that.


I am just starting to take an active interest for this matter so my opinion as an average person is that every solution should be fairly considered irrespective of the politics involved....although I am not really that naive to think that the issue won't go for a political scrutiny....but the government should not do that on a partisan basis, as this is in the interest of humankind present and future.