Two months ago, Daniel Reeves offered me a remarkable bet.  The terms:

1. Bryan reads Climate Shock.  But feel free to skip the parts about short-term extreme weather events — that’s probably least compelling and least relevant to the long-term cost/benefit analysis.

2. Danny puts up $500 to Bryan’s $250 on Bryan doing a 180 on some important policy question related to climate change, such as supporting carbon pricing or subsidizing clean energy or carbon capture tech.  (Merely increasing Bryan’s support for repeal of existing government policies doesn’t count).

3. Bryan automatically loses the bet if he doesn’t finish the book by January 1, 2022.

I have now read Climate Shock, and I’m afraid that the book didn’t change my mind on any important policy question related to climate change.  I really did strive to be fair, and I did warn Reeves that he was overestimating my open-mindedness.  That said, I did win – and the noble Reeves has already paid me.

My main thoughts on the book:

1. Wagner and Weitzman place huge weight on the “fat tails” of climate disaster, and fixate on a 10% chance of hitting 6°C global warming.

Climate change belongs to a rare category of situations where it’s extraordinarily difficult to put meaningful bounds on the extent of possible planetary damages. Focusing on getting precise estimates of the damages associated with eventual global average warming of 4°C (7°F), 5°C (9°F), or 6°C (11°F) misses the point. The appropriate price on carbon is one that will make us comfortable enough to know that we will never get to anything close to 6°C (11°F) and certain eventual catastrophe. Never, of course, is a strong word, since we know the chance of any of these temperatures happening even based on today’s atmospheric concentrations can’t be brought to zero.

One thing we know for sure is that a greater than 10 percent chance of eventual warming of 6°C (11°F) or more— the end of the human adventure on this planet as we now know it— is too high. And that’s the path the planet is on at the moment. With the immense longevity of atmospheric carbon dioxide, “wait and see” would amount to nothing other than willful blindness.

Why doesn’t this change my mind?

a. I’m not remotely surprised that Wagner and Weitzman say there is a 10% chance of disaster.  Given that they’re writing a book about climate change, I actually expected a higher probability.

b. I’m not qualified to assess the research underlying this probability, but I suspect that it is overestimated because (a) predictions of disaster are almost always wrong, and (b) climate experts have a strong and obvious left-wing bias.

c. Furthermore, it is quite clear that climate experts were heavily left-wing long before they started studying climate.  So it is hardly surprising that the smartest people working in this area are so pessimistic.  They started with a more talented team of advocates.

d. Wagner and Weitzman don’t consider the total disasters that might result from aggressive climate policy.  Like what?  Most obviously, their policies keep the world poor, hence war-prone, for many extra decades.  Which in turn raises the probability of World War III before 2100 from say 10% to 15%.

2. Wagner and Weitzman are extremely optimistic about geoengineering, yet childishly reject it.

This is where we’ll end up: with the specter of geoengineering. Everything we know about how humans behave, and how they don’t, leads us to believe that— unless political leaders muster the courage to act, decisively and soon— the world will inevitably be facing some painful choices. It may be folly to believe that technology (in the form of geoengineering) can, once again, bail out society and the planet from the worst of planetary emergencies. But that’s the world we are moving toward.

Talk of geoengineering, much like uncertainty, isn’t very comforting. It shouldn’t be. It’s certainly not an excuse for inaction on sensible climate policy, just as we shouldn’t start smoking because an experimental lung cancer drug treatment showed some promise in a lab. The specter of geoengineering should be a clarion call for action. Decisive, and soon.

Why childish?  Because when they actually discuss the evidence on geoengineering, it’s far more solid than “an experimental lung cancer drug treatment that showed some promise in a lab.”

We may hate the idea of countering amazing amounts of pollution with yet more pollution of a different type. But the entire enterprise is simply too cheap to ignore.

And it’s not like anyone would literally do as Mount Pinatubo did and dump 20 million tons of sulfur dioxide into the stratosphere. At the very least, given current technology and knowledge, the sulfur would likely be delivered in the form of sulfuric acid vapor. Sooner rather than later, we may be looking at particles specifically engineered to reflect as much solar radiation back into space with as little material as possible. That would mean less material to achieve the same impact. It may be a fleet of a few dozen planes flying around the clock. Some have gone as far as to calculate how many commercially available Gulfstream G650 jets it would take to haul the necessary materials. The specifics are indeed too specific. What matters is that the total costs are low, both compared to the damage carbon dioxide causes and the cost of avoiding that damage by reducing emissions.

Actual numbers are all over the place, and all of them are based on estimates, but most put the direct engineering costs on the order of $1 to 10 billion a year. Those are the engineering costs of getting temperatures back down to preindustrial levels. It’s not nothing, but it’s well within the reach of many countries and maybe even the odd billionaire.

If a ton of carbon dioxide emitted today costs $40 over its lifetime, we are talking pennies per equivalent ton. That’s three orders of magnitude lower, and it’s the exact parallel situation to the free-rider problem that has caused the problem in the first place. Instead of one person enjoying all the benefits of that cross-country round-trip and the other seven billion paying fractions of a penny each for the climate damages that one ton of carbon dioxide causes, now it’s one person or (more likely) one country being able to pay for the costs of geoengineering the entire planet — all potentially without consulting the other seven billion people.

The final clause clearly freaks them out.  But why?  They reasonably predict that geoengineering will start slowly.  Are they really worried that “once the genie is out of the bottle,” some tropical countries will decide to freeze the rest of the planet to death?  Or what?

Frankly, it looks like Wagner and Weitzman want to impoverish the world by many extra trillions of dollars to ensure that humanity’s savior is the United Nations instead of the United States or (horrors!) Elon Musk.  Indeed, their objections are so flimsy that you could accuse them of being Straussian proponents of geoengineering.  But that’s a stretch.  Wagner and Weitzman sound like typical smart people under the spell of Social Desirability Bias.  They care such more about solving climate change inoffensively than solving it cheaply.

3. Wagner and Weitzman barely mention nuclear power or the absurd regulatory burden under which it labors.  This fits with the Social Desirability Bias story, and makes me further distrust them.


I freely grant that Climate Shock is one of the best alarmist books on its topic.  Maybe the best such book.  Alas, that’s not good enough to change my mind on climate policy.