Here’s my point-by-point reply to Daniel Reeves. He’s in blockquotes; I’m not.
Daniel gets the last word if he wants it!
Bryan seems to start by acknowledging that 6 degrees of warming (we’re approaching 1 degree so far, for those just tuning in) would be devastating and that a 10% chance of that by the end of the century warrants mitigation efforts. He even acknowledges that — warming being proportional to cumulative historical emissions — we can’t afford to wait.
Not really. My actual view is that I’m not qualified to judge these questions, and reading Climate Shock didn’t make me feel noticeably more able to judge. As I explained at the outset of the bet, I would have to study this subject for years to directly judge the evidence.
The whole point is to assess whether the alarmism is correct. If you dismiss the authors for the very fact that they think alarmism is correct then you are fundamentally closed-minded on this issue and probably shouldn’t have accepted the bet. (To be clear, I’ve paid up already.)
Indeed you have, Daniel. But in my own defense, I did warn you upfront that you were over-estimating my open-mindedness. Given the complexity of the evidence, all a layman can honestly do is assess credibility. Wagner and Weitzman didn’t wow me on that count.
This sounds like assuming bad faith. My sense from the book was that the authors were incredibly conscientious and intellectually honest. But maybe I’m misunderstanding you and you’re agreeing that it’s impressive that the authors resisted the temptation to exaggerate the probability?
My point is just that their claim was more modest than I expected. This has two effects: (a) it slightly raises their credibility, but (b) made me slightly less worried about climate change.
(Also some of the bias is trying to counteract the other side’s bias, which is what turns the whole topic into an epistemic nightmare. I don’t think you can just pin all the bias on the left. Isn’t there even greater right-wing bias to rationalize business-as-usual?)
Both sides are intellectually dishonest. Which is worse on this particular issue? The right is probably worse on the details of the science, but the left is probably worse on the policy analysis. Though again, I would have to study the issue for years to do more than guess.
Some policy interventions — say, funding carbon capture — don’t have that possible failure mode. [of greatly slowing economic growth in LDCs]
Side note: I think Pigouvian taxes should be philosophically fundamental to laissez faire capitalism (by maximizing how much faire we can laissez) and that we want a carbon tax even if — in light of geoengineering? — it’s lower than Wagner and Weitzman recommend. I also disagree that Pigouvian taxes are fundamentally impoverishing. I’m a fan of revenue-neutral carbon taxes.
Wagner and Weitzman didn’t seem very optimistic about carbon capture as a primary policy solution. See here and here for my views on Pigovian taxation. You are correct that Pigovian taxes generally have a lower deadweight cost than regular taxation. Indeed, they can have a negative deadweight cost. Even so, high carbon taxes would plausibly sharply slow poverty reduction in the Third World.
Wait, can I still win this bet on a technicality if Wagner and Weitzman inadvertently convinced you that we should pursue stratospheric aerosol injection (what they mostly mean by geoengineering in the book)? I don’t know how serious I am with that question but I’d love to understand your thinking more!
No, because I’ve long been sympathetic to geoengineering, and the bet requires me to do a 180.
I may be more trusting than you but I’d only have distrusted them on those grounds if they’d argued against nuclear energy. Wagner and Weitzman think policy intervention should be limited to carbon taxes. Nuclear energy doesn’t emit carbon so they are implicitly pro-nuclear. I’m sure they’d agree about the absurd regulatory burden as well.
If they had wanted to signal their lack of left-wing bias, they would have gone out of their way to praise nuclear power. So why didn’t they?
Update: David Henderson is disturbed by my claim that, “Both sides are intellectually dishonest.” If the issue is too complicated to decide without years of study, how can I so casually dismiss almost everyone as “dishonest”? My reply: I’m talking about the vast majority of people who hold strong opinions despite (a) the complexity of the issue, and (b) the minimal time they have actually spent studying the science. You don’t have to understand the evidence to know when other people are forming their beliefs negligently.
READER COMMENTS
Floccina
Nov 16 2021 at 11:28am
When I think of the geoengineering solution of putting something up in the atmosphere that reflects more sunlight, I think could it be done regionally?
Could it be done it in a place that reduce the sunlight hitting Greenland and Antarctica to prevent sea level rise, but would the people in Greenland like that cooling. On the other hand I’d like to see my state Florida, summers cooled, so do you end up with everyone trying to improve their own 100 mile radius climate. Is any of that possible.
Mactoul
Nov 16 2021 at 7:57pm
Indeed, Antarctica is not warming and in fact, had been enjoying a particularly cold winter.
Reducing solar insolation might very well cause rains to fail in unexpected areas and cause far more misery than any realistic warming.
I can’t understand this belief in 6 degree warming. I think its likelihood is far less than 10 percent– maybe exponentially less.
BS
Nov 16 2021 at 12:41pm
>Is any of that possible.
Why would you want to do any of that? How is any one of the proposals less of an unknown leap of faith than pumping CO2 into the atmosphere would have been be if advanced as a solution to “global cooling” in 1970?
nobody.really
Nov 16 2021 at 3:43pm
My understanding is that the reflecty-stuff we’d inject into the atmosphere would dissipate fairly quickly. Thus, geo-engineering would require regular applications to work. But if it DIDN’T work, you could just stop doing it, and the world would revert to “normal” fairly soon. This makes experimentation less threatening. In contrast, the CO2 we add to the atmosphere hangs around for decades or centuries. So there’s a significant asymmetry to the idea of adding reflecty-stuff to the atmosphere and adding CO2.
We still face fascinating collective action problems: Once you start doing it, who gets to control it? Imagine the people of northern Africa decide that they’re tired of living in a desert, and start dumping reflecty-stuff into the atmosphere to make their part of the world especially temperate–even if this makes the rest of the world into an ice chest. Or imagine warmer nations decide to hold colder nations hostage, threatening to dump ever more stuff into the atmosphere unless the Warmies receive tribute. Who knows what fun we can have with this?
Andrew_FL
Nov 16 2021 at 7:56pm
Orbital mirrors are both permanent and reversible
BS
Nov 17 2021 at 12:45pm
How big would they have to be? What would be the risk of ending up with more pulverized (and pulverizing) junk in orbit?
Andrew_FL
Nov 17 2021 at 2:38pm
Depends where you put them mostly, but lots of smaller mirrors is better if you want finer control
However you wouldn’t likely position them in currently crowded low Earth orbital space, but at the L1 Lagrange Point, so collisions with currently artificial satellites & space junk aren’t a big concern.
nobody.really
Nov 16 2021 at 4:27pm
Caplan and Reeves pose fascinating epistemological questions: To what extent is rational argument an illusion?
I generally have high regard for expertise. Why? Well … probably because I was raised in a professional household and people in my family got advanced degrees, and I wield a bit of it myself. Can I really say that I understand what my family members do or say? Not entirely. But they’re part of my tribe, so I (mostly) trust them. It’s not about knowledge; it’s about trust. So why should I expect other people to embrace expertise–especially people from different tribes? And by what right to I withhold trust of their tribe’s norms and philosophies?
Ok, it’s not just about trust. I also have learned certain models of the world a/k/a preconceptions. I’m more likely to trust experts who say things that do not conflict with my preconceptions–or, at least, don’t conflict too much.
Here, Reeves invites Caplan to review a book by reputed experts. Caplan concludes he is not in a position to evaluate their expert analysis–a nice expression of intellectual humility–but because they draw conclusions that conflict with his preconceptions, he takes that as sufficient grounds to hold their claims in dispute.
Caplan has had formal training in economics. He has elected to publish books on voting, child rearing, education, and immigration. I can’t claim any expertise in any of these topics (except the standard “I had six theories about raising children; now I have six children and no theories”). Sure, I might find his arguments persuasive–just as I might find Wagner and Weitzman’s arguments persuasive. Which of us laymen would have the hubris to be think ourselves qualified to evaluate any of those claims?
Mactoul
Nov 16 2021 at 8:06pm
But the claims are in dispute among experts. In particular, the central claim of 10 percent probability of 6 degree warming is not generally accepted. So it is entirely rational for Caplan not to do a 180 if he can neither evaluate the claims himself nor believe the claims to be unanimous opinion of the experts.
nobody.really
Nov 17 2021 at 3:32am
Surely claims about voting, child rearing, education, and immigration are disputed, too. By what theory would I ever judge myself in a position to evaluate any of the ideas in Caplan’s books (or most books)?
Don’t get me wrong. I haven’t read Wagner and Weitzman’s book, and it’s not on my list. In truth, the issue seems kinda academic to me since I don’t anticipate making any big decisions related to climate change. Ok, I guess I continually chose to live according to a number of status quo practices that result in energy consumption. And from time to time I fly on airlines, so there’s that. I tend to vote for Democratic candidates, but not specifically regarding climate policy, so again climate issues have not been on the margin.
But if push came to shove, I suspect I’d make choices based on my tribe’s beliefs–not on the basis of my own critical evaluation of the evidence. It seems as if Caplan would do likewise. We’re just members of somewhat different tribes.
Philo
Nov 16 2021 at 11:50pm
“I would have to study this subject for years to directly judge the evidence.” And even then, your judgment might well be that the evidence is indecisive.
Thomas Lee Hutcheson
Nov 17 2021 at 7:06am
So where does BC come out on policies to deal with the increase in atmospheric CO2?
Daniel Reeves
Nov 17 2021 at 1:00pm
Huge thank you to Bryan for the debate and the kind offer of the last word. I have some notes for my official reply that it would be awesome to run by the commentariat here, if that’s ok?
(1) I think I’m content to let Bryan have the last word on the “well, they didn’t wow me enough what can I say” part. (Like maybe him saying that makes the case better than I can that Bryan’s libertarian bias is preventing him from soberly assessing the scientific consensus on climate change. Maybe linking to Scott Alexander’s “Learning to Love Scientific Consensus” would be helpful?)
(Side note: Please don’t bristle at “libertarian bias”! David Friedman, who’s far to the right of Bryan on this question, is refreshingly candid about his own libertarian bias. He put it something like “I have a strong bias against believing a scientific conclusion for which the solution is coordinated government action”.)
(2) But previously Bryan’s complaint about climate activism was lack of cost/benefit analysis, so I guess this feels like moving the goalposts?
(3) I think carbon capture is looking more promising in the 7 years since the book was published. Check out stripe.com/climate (which Beeminder is helping, a tiny bit, to fund: beeminder.com/climate)!
(4) As for why the authors didn’t signal their lack of left-wing bias by going out of their way to praise nuclear power: Maybe they weren’t looking for ways to signal their lack of left-wing bias, or just thought the topic riles people up and would distract from their core points. Or maybe they just think that nuclear power is good exactly to the extent that the market says it’s good, assuming externalities are priced correctly. I.e., no need to praise it just for the sake of signaling.
(5) I think I’m most disappointed with Bryan’s uncharitable take on the authors’ take on geoengineering. I called it Bulverism. Bryan claims that the authors, in their despicable leftism, hated geoengineering on principle. He seems to have entirely skipped over their arguments for why geoengineering would actually be bad, climatologically.
(6) I believe the “10% chance of 6 degrees of warming” estimate has gotten a bit less dire in the last 7 years, thankfully. I don’t think that that impugns Wagner and Weitzman’s credibility, just that we’ve gotten more data and climate models gradually improve. Also that estimate was based on emissions projections which are gradually improving as we take gradually take climate change more seriously.
(7) Climatologists say there’s an X% chance of civilization-decimating amounts of climate change, even with geoengineering on the table. That X doesn’t have to be very high for emissions reduction to be necessary. Latest estimates may have it fairly low but not much under 1% if you account for model risk. For Bryan to read this book and be like “well probably the numbers are wrong though la dee da bias” or to fixate on how the authors don’t take geoengineering seriously enough because of how leftist they are, is frustrating.
Thanks also to the commenters on the previous posts in this series! Some good discussions there. Again, eager to hear more of your thoughts on the above notes before I turn it into my official final reply!
Mactoul
Nov 17 2021 at 6:45pm
Daniel Reeves,
I wonder if you have read Unsettled by Steve Koonin which is a well-regarded sceptical take by a person who is not on libertarian/conservative side at all. Would like your comments on that book.
Vera
Nov 18 2021 at 6:46pm
What other opinions do you hold that can only really be supported by years of in-depth studying? (I can think of one: sympathy for geoengineering!) This is a cop-out – trusting those who you judge to be unbiased experts is a critical step in almost every opinion.
And on that point, while the left is now associated with climate change, that was an endogenous process, so the fact that someone is on the left does not automatically mean that they are trying to pull one over on us. (I’m not on “the left” but I can recognize that.)
Alex Viladot
Dec 11 2021 at 5:08am
“Even so, high carbon taxes would plausibly sharply slow poverty reduction in the Third World.”
Not necessarily.
At this moment the reduction of a set amount of carbon is much cheaper in the Third World than in rich countries, by the law of diminishing returns (richer nations have been doing a lot to become greener in the last decades, whereas poorer ones haven’t).
If we start from the premise that any person on the planet has exactly the same right to emit carbon as any other person, we could conclude that Third World countries are emitting way less carbon than they would be entitled to if we were to say that current levels of carbon emissions were acceptable.
If we consider current levels unacceptable, a cap-and-trade system among nations should be put in place (if only that were politically feasible!). The cap should be diminishing every year by a specific amount until acceptable levels were achieved in an acceptable time frame.
What would that mean? At the outset, rich nations would be paying poor ones for their emission rights, and poor nations would have an incentive to reduce their already smaller carbon footprint as long as that made economic sense.
Of course, with time, and as global emissions targets would decrease, a point would be reached were it would start harming Third World economies as well, but where is that point and how long would it take to reach and would it even actually ever be reached for all poor nations?
The thing is that this idea is already being used. Switzerland is paying poorer nations like Peru to actually reduce their carbon emissions. They have figured that it is cheaper (lower hanging fruit) to pay Peru to reduce their carbon emissions by say 1 Ton than trying to reduce the same amount in their country.
Looks like a win for poorer nations to me. They get to have better air quality (carbon emissions go usually in tandem with other, locally harmful, emissions) without having to pay for it. At the same time, we all get to benefit from a reduction in global carbon emissions.
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