Arnold also writes:
Pearce himself said, and I agree, that skepticism about climate models should increase one’s concern about both tails. That is, the models may under-predict global warming. In fact, that is my number one concern with the issue. His book, which I bought, is a litany of potential disaster scenarios, from peat bogs dissolving and releasing massive amounts of methane to ice sheets quickly breaking loose into the ocean. Even though these scenarios are not in the scientific consensus represented by Dr. McCracken, I think they are the right things to worry about.
I’ve got to disagree. As I’ve argued before, all predictions of severe disaster should be treated with utmost skepticism, because they are almost always wrong.
Yes, this too is a defeasible presumption. But in light of the track record of doomsayers through the ages, it’s reasonable to expect overwhelming evidence before we abandon this presumption.
READER COMMENTS
Michael E Sullivan
May 1 2007 at 9:50pm
Your theory has a problem with survival bias.
The fact that we are here is good evidence that we’ve experienced a long, long time without disasters.
But in fact, there *have* been severe disasters in history. Let’s bear in mind, that while many severe disasters have been predicted and the predictions turned out to be specious, many other predictions did not come to pass, because people *heeded the warnings*.
Talking about thick tails is not the same as doomsaying. No serious climate scientist (few?) is predicting that disaster will happen, only that there is a small chance of disaster (and then only under scenarios that fail to halt CO2 emissions growth within the next 30 or so years). The question is “how small?” and our data and models aren’t yet good enough to give a very satisfactory answer.
aaron
May 2 2007 at 6:11am
Even without GHG AGW, these possibilities still exist and probably aren’t even much less likely. That makes uneconimical mitigation (regulation) efforts downright ridiculous.
Paul Vigna
May 2 2007 at 9:56am
The question of global warming isn’t what are we doing to the Earth. The Earth will shake off whatever we throw at it. The question is what are we doing to ourselves, and the cities and towns we live in.
Go to any third world country that’s industrialized but doesn’t have the kinds of environmental laws we have in the U.S., and you can see how unhealthy unchecked industrialization is. Just look at what China’s going through.
We may not destroy the planet, but we can make our own lives very miserable.
Bob
May 2 2007 at 12:34pm
It seems to me that although global warming might be a black swan, it’s highly unlikely because
1) it’s almost a given that you don’t see a black swan coming and
2) if positive feedback made the climate highly unstable, I’d expect to see regular cascade-style changes due to natural variation – that is, radical climate change might be rare, but it wouldn’t be new. It’s not clear to me why the climate would be locally stable (negative feedback) but at some point shift to unstable (positive feedback).
In the end if you’re worried about civilization-ending events, I think you want to be as rich and advanced as possible to be able to best deal with surprises.
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