Bryan Caplan  

Why I Believe in Moderate Global Warming, But Lose No Sleep Over It

Overconfidence... Supreme Court Overturns Per Se...

Evolution and genetics aside, my understanding of natural science is very weak. Fortunately, examining the bets experts are willing to make is a great substitute for understanding what they are talking about. So when Robin Hanson reports that global warming skeptics aren't betting, at least at reasonable odds, I infer that strong skepticism is cheap talk.

At the same time, I don't see the climate change bet as very interesting. Why not bet on world per-capita GDP and life expectancy in 2057 (or 2107) conditional on doing nothing new about carbon emissions. Does anyone want to bet $100 at even odds that per-capita GDP in fifty years won't be at least 50% higher, and life expectancy 3 years longer, even if we take the do-nothing-more path?

Is the do-nothing-more path too improbable, or too hard to define? OK, then why not just make the unconditional bet that in 2057, per-capita world GDP will be at least 100% higher, and life expectancy 5 years longer? $100 at even odds? If that bet isn't attractive too you, it doesn't mean that doing something about climate change isn't worthwhile, but it does mean that, all things considered, the future is pretty bright.

Feel free to refine the bet in the comments.

Comments and Sharing

COMMENTS (13 to date)
caveatbettor writes:

This is why we need global warming contracts on a prediction exchange!

David Thomson writes:

My understanding of natural science also leaves something to be desired. Still, I have done more than enough reading to become very cynical and suspicious concerning those who claim that global warming is a major problem. If nothing else, they are almost certainly well compensated financially. Their opponents are not lavishly funded whores of the supposedly evil oil companies. No, they are often brave individuals risking their reputations and future incomes. They may be lucky to receive a dollar for every one thousand obtained by the hysterical alarmists. The United States government alone spends over seven billion dollars annually on this crusade. Guess who gets ignored when the grant committees make their decisions?

We also should be aware that the global warming whack jobs minimally at a gut level realize that their crusade will provide them with enormous power. They are, after all, altruistically inclined and highly credentialed elites who should be running the world. We comprising the ignorant sheep of society should graciously accept their benevolent guidance. Allow me to be brutally frank: these clowns are the progeny of the American Progressive movement of the previous century. What more needs to be said?

Tim Worstall writes:

Well, the problem with those bets is that, umm, climate change is actually predicated on those things happening.
Have a look at the SRES (the economic models upon which the IPCC process is based).
Within the whole process we are already assuming that GDP per capita is going to continue its couple of centuries long rise.

Lord writes:

I don't expect to be around then, so it would be rather foolish to bet. Hey kids, it's your problem.

Matt writes:

Isn't it obvious why no one wants to bet? The entire discussion is hypothetical. No one can prove their assertions.

Here some of the positions
1.We simply don't know why the climate is warming. Climatology is too young a science.
2. The climate isn't warming, cities and land management have caused ground temperatures to rise. Our measurements are wrong.
3.The Sun is causing the warming and based on sunspot cycles we had better get ready for global cooling.
4.We simply don't know. Climatology is too young a science.
5.The warming is natural and man has no effect.
6.The warming is mostly natural and man's effect is slight.
7.The warming is mostly natural, but man's effect exacerbates the problem. Very mild corrective measures are needed. (Lomborg)
8. The warming is manmade but who cares? People like warm weather! And the economy will benefit!
9. The warming is manmade and countries that stand to benefit should have to compensate countries that lose.
10. The warming is manmade and a problem, but we can't stop it without causing bigger problems.
11. The warming is manmade and a disaster, and we must do whatever it takes to stop the problem.
12. Cow farts and worms, man.

Horatio writes:

My natural science background is very strong and I am skeptical of AGW, at least to the extent that alarmists claim. The issue gained my attention a couple of years ago so I decided to read up a bit. My conclusion, it's too complicated a system to be making these types of predictions. Also, beware any non-climate scientist who accepts/denies the "consensus", unless that scientist has invested the time to read the literature. An average particle physicist knows no more about the climate than an average economist.

However, climate change is happening and this is possibly an area where a real market failure exists. Even assuming humans have no effect, the earth will see major climate changes in the future. We should invest in the technologies needed to maintain our planet at approximately its current climate or risk extinction when the next big change happens.

Les writes:

For all issues it is important to differentiate facts from opinions. In the case of so-called global warming there are few if any facts beyond this one: over the past 150 years, average global temperatures have increased about one degree Centigrade. Practically everything else is opinion, rather than fact, and mostly these opinions are assumptions built into computer models that purport to predict future climate.

Under these circumstances, it is far from established that global warming has or will occur.

Sinclair Davidson writes:

Define a 'bet'. I have bought a house at the beach for several hundred thousand (Australian) dollars. If global warming occurs to the extent predicted, I'll lose that entire amount. That, to my mind, is a bet; yet I keep being challenged to take a bet.

reason writes:

mmm mmm. And if globals warming causes some major famines your in the money! Nice trick.

Jeff Evans writes:

Don't confuse the absence of bets with unwillingness to accept the risk - a well developed, liquid market with properly defined contracts would likely attract interest. Unfortunately, this requires 50+ year time horizons before payoffs occur - most betting exchanges likely won't exist that long!

Skeptics are probably unwilling to place bets because of poorly developed institutional betting frameworks, not because they don't "believe" their views

Karl Smith writes:

The serious reason to lose sleep over global warming is that its effects are not likely to be evenly distrbuted.

Indeed, the people who are hit hardest by warming are those who are the poorest and unable to mitgate its effect.

The cruel irony that causes many of us to loose sleep is that US may be a net beneficairy of global warming, while people living in low lying areas of Bangladesh may suffer the hardest losses.

Mr. Econotarian writes:

I have a greater belief in global warming than my belief in the ability of governments worldwide to actually be able to reduce carbon and methane emissions.

Nuclear is the only reasonable low-carbon base power system. CO2 capture from coal is much more questionable and riskier (from a global warming perspective).

Solar and wind can play a role in peak power (maybe an important role at some point), but will never provide a serious base power level until we have large solar satellites, which would take a revolution in space access (like a space elevator). Nuclear fission power is available safely right now.

Constant writes:

"So when Robin Hanson reports that global warming skeptics aren't betting, at least at reasonable odds, I infer that strong skepticism is cheap talk."

One clear possibility is that if there's one side that's willing to bet, it's deluded into thinking it knows something about the future and so the bet would be no gamble at all, and if there's one side that's not willing to bet, it has correctly assessed that nobody knows and so the bet would be a gamble.

In short, a lopsided willingness to bet is entirely consistent with delusion on one side (the betting side) and clear perception that the whole thing is highly speculative on the other side (the non-betting side).

I actually think the planet is warming but I would not be willing to bet that it will be warmer in 50 years. However, as one component in a diversified set of bets to minimize my risk, I might be willing to place a bet.

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