Yes, climate change is a problem and yes, we do have to do something: but in Britain, we've done it already?

Or, Timmy in the Torygraph. Its a bit broken I’m afraid, though it manages to get some obvious things right. But before I start on the actual matter, we need to sweep away some of the dross.

It starts Perhaps we can sit down and discuss this climate change thing like the adults we are? Put the Delingpoles over here, the vilenesses that are Greenpeace… and the problem – repeated elsewhere – is the pretence of equal treatment of the two “extremes” whilst actually clearly favouring one side. The bias continues in the treatment of climate sensitivity, though for something appearing in the Torygraph it isn’t bad.

The problem is the continuation: Timmy tells us that the IPCC range is 2-4.5 oC, that there are entirely honest and reasonable scientists… out there arguing that this range is either too high or too low (dubious, but we don’t need to worry about that for now) and that It is this “we don’t know” that leads to needing to do something. Economists call this uncertainty, and the correct and reasonable reaction to uncertainty is insurance. This is a broken variation on something I’ll call “mt’s argument”, because as far as I know mt is the person who has been making the (correct, unbroken) version of the argument for longest.

mt’s argument is that uncertainty does not help the cause for inaction, although it is frequently used as such by denialists and the lite. The idea that we don’t know enough climate science, or we don’t know enough about climate sensitivity to pin down its value, and therefore we should do nothing, is twaddle. And this is for two [*] reasons: the first and most obvious is that if there is uncertainty in climate sensitivity, then to first order it is as much on the high side as on the low side, so the mean damage is sort-of the same; so even at the idiot-argument level, it doesn’t work. But the other is that damage is non-linear in sensitivity, in the bad way, increasing faster than linear; so for symmetrical uncertainty about the mean, the more uncertainty, the higher the mean expected damage.

But that isn’t what Timmy is saying. Timmy is asserting that only uncertainty makes action necessary. That if we knew, for certain, that climate sensitivity were 4 oC we would need to do nothing. This, of course, makes no sense at all. Fortunately, this doesn’t much matter, because the uncertainty is much less than Timmy thinks; as any fule kno, climate sensitivity is 3 oC.

The rest of the article argues for a carbon tax, and of course I agree, though I don’t agree that Stern is a good source for the correct numbers.

[*] Oh all right 3: because the distribution of climate sensitivity is limited below (effectively by 0.7 oC, unless you’re a nutter, definitely by 0, unless you’re a true wacko) then “uncertainty” about an expected value implies (to first order) more uncertainty above than below.

17 thoughts on “Yes, climate change is a problem and yes, we do have to do something: but in Britain, we've done it already?”

  1. Fortunately it doesn’t matter whether Stern is the right source for the price of carbon. The point is to try some nonzero price, and then adapt the tax until it actually gets the job done. The market (gradually) does its job of revealing the right price, without the silliness of trying to make a market waltz down a fixed quantity corridor, as in a tradeable permit scheme.


  2. Well yes, but Tim was writing for the Telegraph. Look at how hostile the commentators were. The general view of Telegraph readers seems to be along the lines of “I think the scientific consensus is wrong because wibble teapot, therefore this is all a leftist conspiracy to stop me exercising my birthright to heat my patio and drive a big car”. Faced with this line of thinking, the argument that you can’t be sure so let’s be sensible and do something prudent seems to me to be more likely to be effective than trying to persuade them to look at the science. For these guys, science is about as arbitrary as Latin declensions, but a lot harder to grasp.

    [Yes. I’m surprised by the commentators hostility. My mother reads the Telegraph and she wouldn’t have written that :-). Indeed there are (I know) any number of perfectly sensible mild-mannered Telegraph readers out there. But I suppose that readership doesn’t post to blogs – my mother never would -W]


  3. Actually, the aqctual climate sensitivity is at least 4.5 oC. Called Earth system climate snesitivity or something like that. The 3 oC figure is for the fast feedbacks only.


  4. The premise is false. Recent social science research indicates that scientific uncertainty is not cause of government inaction. The cause is the uncertainties surrounding the policies themselves. These uncertainties include structure, implementation, targets, and effects.

    The carbon tax is an example. What’s the rate; on whom is it levied? How is it collected; who bears the burden? What is the level of disruption? How is success or failure measured?


  5. I think William’s last point about a zero lower bound is important. I previously thought that the known unknowns had policy implications but you can’t do anything with the unknown unknowns. OTOH, climate change has very limited upside and lots of potential downsides. We can guess that there are truly unknown factors that we haven’t figured out. They have limited ability to make things better, but much more ability to make things worse.


  6. Poor Dellers writes like someone hit too hard upside the head by the lead loaded umbrella of some Hanoverian head boy/


  7. The Torygraph might well be read by reasonable people but it is also read by many very right-wing people. Booker and Delingpole get paid to write stuff that appeals to a large part of its readership. Here’s a nice example.


  8. Lars,

    Yes, of course, although he clearly believes every word of the insane drivel he writes. You might not be aware of the Horizon (BBC2 science series) where he told Sir Paul Nurse how “real science” is done.

    But my point was about the Torygraph: it’s seen as a serious newspaper yet it provides platforms for Booker and Delingpole.


  9. Delingpole is not misrepresenting the study. He hasn’t even read it.

    He is the “interpreter of interpretations”. He came up with that line himself when Paul Nurse pwned him on Horizon. He freely admits that he doesn’t read primary sources, because he doesn’t understand them, and “doesn’t have time”.

    So all he does is look at some blog that tells a load of lies and repeats them. In national newspapers. He really does rate bloggers above, say, professors when it comes to science.

    See RationalWiki for more fun on Delingpole.


  10. Lars,

    When I hit your link it went to a figure in the study. Where’s the despicable part? Not saying there isn’t any, having not ever read Dellingpole.

    Under the figure the study says: Contrary to SCT predictions, higher degrees of science literacy and numeracy are associated with a small decrease in the perceived seriousness of climate change risks.

    It concludes that for climate science a new communication science, not based on the information deficit model is needed to affect policy decisions. It offers several possible avenues looking for a focus. Unfortunately, the study is ignored or dismissed in much of the climate world


  11. “I don’t agree that Stern is a good source for the correct numbers.”

    Interestingly Tim Worstall seems to have changed his mind on that somewhat – asked why he now seems to support Stern after initially criticising him

    “Partly it’s because I’ve been convinced by some of the subsequent work looking at some of Stern’s assumptions. I’m still not entirely convinced by his discount rate for example but I am convinced that standard market interest rates shouldn’t be used. I also think Weizman has a good point about uncertainty.

    Some of my other criticisms remain. Using A2 only for example.”


  12. Unfortunately [redacted – W], you are a ‘Timmy’ as well; just a lefty version of upper middle class privilege the only difference is, you still hate those horrid people that have to get on with trying to feed you and your like. There is a still chance though that you might yet grow up, I see the pony tail has gone already and that’s an encouraging sign.

    [What are you on about? -W]


  13. That link should have a warning, PeteB. Some of the follow on comments are still of the ‘they changed global warming to climate change’ type. Not that the Bish is equipped to recognise the stupid.


  14. Tim has a piece at Forbes.

    [Yeah, I saw that. I keep meaning to write a piece on discount rates myself, despite my ignorance.

    Timmy’s piece isn’t really very interesting, unless you believed Stern in the first place. All it says is that *if* you believed Stern, and *if* you believed that his discount rate of 0.1% did what he claimed – viz, accounted for extinction risk, *then* the discovery of new extinction risks ought to raise your discount rate, and therefore lower the present-day costs.

    However, AFAIK no-one really believes that Stern’s 0.1% was anything other than a small number plucked out of thin air, so Timmy’s argument is nothing more than playful -W]


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