Bray and von S

Posted by William M. Connolley on August 9, 2007
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Apologies – back to climate, but opinion, not science. Bray and von Storch ride again! See Nature’s blog and a long write-up of their results.

In the blog, they attack Singer for taking stuff out of context, and the skeptics for misrepresenting their results. But they also defend the methodology of the 2003 survey, which Tim Lambert attacked [update: TL maintains his opinion]. I’m still dubious about the possible selection bias, though the good news is that they will address this in the next version.

But they also need to redesign the questions (as they note). The most headline-y one was “Climate change is mostly the result of anthropogenic causes.” The answer to this depends a lot on the timescale you’re thinking of. If you mean 1000′s, or 100,000′s of years, then the answer is clearly no. If you mean last-50, then the answer is clearly yes, unless you’re a wacko. The possibility of misinterpretation of the question (I assume that B+von S meant recent change) makes the results difficult to interpret.

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  1. #1 MarkH
    2007/08/10

    I read the survey and while I agree the numbering system is really stupid and non-specific, it doesn’t seem all that bad to me. Large majorities agree that global warming is happening, that CO2 is a greenhouse gas, that climate change will have harmful effects. I can see with many of the questions a great deal of noise – largely because the questions lack specificity, but only with cherry-picking could one come to the conclusion it shows anything less than a majority of climate scientists agreeing with the major points.

    Now, models get a drumming. But when don’t they? It basically reads to me that the scientists (or whoever) surveyed believe in the basic mechanics of the warming world but are justifiably uncertain about prediction, and think that global warming will be a mixed bag of effects – albeit mostly negative.

  2. #2 Sparrow
    2007/08/10

    “The answer to this depends a lot on the timescale you’re thinking of. If you mean 1000′s, or 100,000′s of years, then the answer is clearly no.”

    When it comes to cooling it’s obvious orbital cycles play a far greater roll than current CO2 due to albedo effects of the ice sheets. But it is my understanding that CO2 can trump the orbital forcings. If this happens then the much more powerful cooling effects of the ice sheets (albedo is 2/3 and CO2 is 1/3 of the forcing if I remember correctly) never come into play. Is this true?

    The question of nature vs. man is a tricky one because if man has the power to stop the ice ages by making relatively small changes then the headline will have to be reworded again.

  3. #3 Steve Bloom
    2007/08/11

    “But it is my understanding that CO2 can trump the orbital forcings.”

    Oh, yeah? Well, I’ll see those orbital forcings and raise you continental drift!

    Mixed card game metaphors aside, really it’s just a matter of how far back you want to go. And what is “mostly”? A majority? 75%? 99%? Do you have to answer no if you think it’s 100%?

    Assuming they can solve the sample problem (which I seriously doubt), von S. and B. should probably try to find themselves a professional survey type to design the thing.

  4. #4 Hank Roberts
    2007/08/17

    Speaking of asking people’s opinion, have you any pointers to what came up in discussions at “a meeting on complexity in nature organised by the British Antarctic Survey in Cambridge …” in the last week or so? The only mention I found was http://thescotsman.scotsman.com/international.cfm?id=1294172007

    I assume they agreed it is complex.

  5. #5 SomeBeans
    2007/08/17

    There’s a one page report on the meeting in New Scientist:

    http://environment.newscientist.com/article/mg19526173.900-climate-tipping-points-loom-large.html

    (You need a subscription, or the paper copy to read it all) Aside from the runaway tipping points mentioned at the top there is a comment linking to the paper described here:

    http://www.lse.ac.uk/collections/pressAndInformationOffice/newsAndEvents/archives/2007/ClimateChangeReport.htm

    The problems with the statistical interpretations…

  6. #6 Hank Roberts
    2007/08/17

    Thanks, that was very helpful, and the second link led me eventually to a press release with a pointer to abstracts:

    … For full details of speakers, programme and presentation abstracts visit:
    http://www.antarctica.ac.uk/about_bas/events/complexity2007/complexity_timetable.pdf