Talk in the town

Last night’s session with the Skeptics in the Pub in Christchurch was an interesting experience (some nice feedback too, thanks). It gave me a chance to develop a few of the thoughts that have been running through my mind recently — and it’s good to do that by presenting them to an audience willing to explore and challenge ideas. The question session at the end ran for about 40 minutes, and the best moment came when one sceptic (no “k”, he was clearly of the “not persuaded” variety) had been pushing me for a worst case. I said that it was conceivable that climate change could end our civilisation. The questioner turned to the rest of the audience and asked them if they really believed that, to receive a chorus of agreement and nods. That’s what happens in the real world: when sceptics leave the comfortable certainty of Wishart-world or Treadgold territory, µWatts or Morano’s depot, they find that the rational world is coming to terms with the real risks.

I promised the group I would make my slides available: they’re here [3.3MB pdf]. The first half of the talk dealt with some basics, and ended with a Katey Walter earth fart lighting session. I then moved on to explore some of the reasons why there is so much manufactured doubt about the reality or seriousness of climate change. The slides are reasonably self-explanatory, happy to discuss in comments.


Many thanks to John Cook at Skeptical Science for making so much of the necessary material so easy to find and use. And for the iPhone app…

[The (older) Pretenders]

29 thoughts on “Talk in the town”

  1. It sounds like a grand evening, Gareth. Last night the place to be in Wellington was the Town Hall, to hear Martin Rees' lecture organised by the Royal Society. He is an extremely eminent scientist, and is the current president of the Royal Society of London. To make a long story short he threw the weight of the Society behind climate science – it was probably the main theme of the talk, in the context of human impacts on planet earth. He also ranged far and wide over other topics: bioterrorism, species extinctions, the global village and space exploration. I'd have liked to hear a bit more about astronomy – he's also the Astronomer Royal – but he clearly considers the future of humanity to be the more pressing subject.

      1. He was a very elegant speaker, DW. Beuatiful turn of phrase, funny and sharp. They're replaying the lecture on Nat Rad on Easter Sunday.

        1. Excellent. I can't say I've listened to such lectures in person, but Richard Alley is likewise a great communicator of the science.

          Oh, and good on ya Gareth, who knows you may have pulled a couple of heads up out of the sand.

  2. Barry: I read the link at Quadrant and it seems to me that the cart is well ahead of the horse. Being distracted by fractions of a degree ignores the question of what is the blanket effect of the rising CO2 & other GHGs or the visible and well documented changes in the polar regions and elsewhere. We know how much surplus fossil carbon has been released, we know what effect that will have, we know the planet is being affected by something and there doesn't appear to be any other causes.
    If it looks like a duck and quacks like a duck….

  3. Ah–hem. Some honesty afterall

    End-phase of the Climate Wars?

    March 22, 2010

    History may see the interview of CRU’s Professor Phil Jones by the BBC’s Roger Harrabin on 12 February 2010 as the opening of the end-phase of the long-running “alarmists versus sceptics” debate.

    The gap between these two schools has never yawned as widely as media reports often suggest. Both agree that climate is always changing, that we have recently been in a warming period (with tiny temperature changes), that “greenhouse theory” has some validity, and that human activities are capable of impacting climate. The core dispute lies in the detection and attribution of ‘anthropogenic global warming’ (AGW), and is brought out in the following exchange:

    Harrabin – How confident are you that warming has taken place and that humans are mainly responsible?

    Jones – I’m 100% confident that the climate has warmed. As to the second question, I would go along with IPCC Chapter 9 – there’s evidence that most of the warming since the 1950s is due to human activity.

    Sceptics say any human causation was trivial. This dispute was addressed directly:

    Harrabin – what factors convince you that recent warming has been largely man-made?
    Jones – The fact that we can’t explain the warming from the 1950s by solar and volcanic forcing.

    “The warming from the 1950s” didn’t actually commence until 1975, and the 1975-2009 warming is identified by Professor Jones as a trend-rate of temperature increase of 0.161C per decade.

    This decadal figure is significant, but only just. In the second interview question, Jones says a trend of “0.12C per decade is not significant at the 95% significance level”.

    The world has been experiencing a long-term gentle warming since the end of the Little Ice Age. Professor Jones has said elsewhere[i] that this natural variability has averaged 0.11C per decade. So, the “extraordinary” recent warming that calls for explanation is the balance of 0.051C per decade.

    This is the smoking gun. It is the sole evidence that a measurable but unexplained increase in global temperatures has coincided with the post-1950 increase in human-induced greenhouse gas emissions. Jones says that this correlation is evidence of causation, because the IPCC has no other explanation.

    The first rejoinder by sceptics is that this is an argument from ignorance. Humanity cops the blame solely because IPCC researchers know so little about all the vast natural forces and cycles influencing global temperatures that they can’t pin it firmly on any one suspect. Cast in this way, the strength of the IPPC’s case is inversely proportional to the depth of their climatic understanding. But why should homo sapiens be the default option?

    Secondly, doubters say it is not surprising that IPCC models can’t explain an infinitesimal heat anomaly of five-hundredths of a degree over a 10-year period. They have a track record of being wrong about much larger matters, including their prediction of 0.2C warming over the past decade. Phil Jones says there has been no significant warming since 1995.

    Thirdly, a very important question arises as to the precision of the instrumental record, as well as all the statistical processing, that produces this key trend figure of 0.161C per decade. This seems an impossibly precise figure for all the world’s temperatures, over lengthy periods, in all seasons, using diverse and changing instruments. What are the margins of error for the thermometers? What are the statistical confidence intervals for the homogenization of records? What of the spatial and temporal gaps?

    Error bars narrow over time, but the IPCC accepts that even the most modern gridded readings contain errors of +/- 0.17. When this level is applied to Professor Jones’ trend for 1975-2009 it overwhelms it. The anomaly which “we can’t explain” is so small as to be swamped by the margins of error.

    Doubts about the accuracy of data processing are heightened by the ongoing unavailability of worldwide raw data and metadata. CRU evaded Freedom of Information obligations and then confessed that computer data was lost. This pattern was mirrored by the actions of NIWA in New Zealand, and perhaps others. What of the ‘Climategate’ accusations of manipulation, also mirrored in New Zealand? There are a great many known unknowns, and perhaps just as many unknown unknowns.

    The fourth objection is that a trend of 0.161C per decade is NOT outside the boundaries of internal natural variability. This is where the BBC testimony of Professor Jones becomes invaluable in settling the argument:

    Harrabin – Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?
    Jones – The 1860-1880 period is only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different.

    and theres much more from the interview. Too much for here

  4. Sorry I missed the Twisted Hop gig Gareth, I got stuck at work until too late. Did make the City Council effort at the Theatre Royal last night (Tues). Very good, the powers-that-be are aware of looming problems, although I fear they are aiming too low. Taking the IPCC lower estimates when we are aware that they always opt for a conservative projection to avoid 'alarmist' accusations. It should be noted that the high tide limit on the Avon River is less than 500m from Cathedral Square.

  5. Your successful presentation to a group of “skeptics” is truly a wonder. Even Goebbels would have been proud of you. Tell me, did you use the “hockey stick” picture or perhaps a poor polar bear swimming in the ocean, or what about the ever popular melting ice shot? The belief in AGW requires a suspension of all critical thinking. How ironic that many of the skeptics present must have shaken off the insanity of belief in imaginary beings but were sucked in by the new high priests of lies – the scientists. Were it not for L. Ron – I’m sure environmentalists would have loved to use the term Scientology to describe their beliefs.

  6. Looking at your slide show is quite alarming.

    The second half of the presentation is simply a made up attack on skeptics that has no ties to reality. Slide 1 starts the presentation by painting the ‘denier’ as someone who belives Elvis is still alive and the moon landings never happened. The debate has been degraded before the slide show has really begun.

    Slides 14: Very vague and meaningless slide. Where does the data come from?? Following the link it seems like it was just made up. What is ‘substantial cost’? What does actual scientific meta analysis suggest??

    This study (below) looks at the scientific literature and finds that most studies deem it likely that climate change will cost less than $25 per tonne of carbon dioxide, however there is large down side risk (chance that it will cost lots more).

    1. That's a fully referenced and documented "made up attack". I suggest you exercise some real scepticism and do some reading on th background to the campaign to delay action. Post coming shortly with news of a good overview.

      I wonder why you had to pick a 2004 paper by Richard Tol? Could you find nothing more recent to support your case? I'll stick with WG3 and Stern, thank you very much.

      1. The point is it’s a meta analysis. It is not based on one study.

        Your slide made claims about where the majority of estimates place the cost of climate change. You have accused me of false representation in the past, now you are doing this to me. I made no claims about what estimate was correct (although the study I quoted does). My only claim is that your graph is not referenced and non-definitive (does not quantify ‘substantial cost’).

        In terms of the roots of ‘climate denial’ (who ever denied the existence of a climate???). This is a false debate. Sure some people who promote anthropogenic climate change scepticism may have disingenuous motives. But this does not prove anthropogenic climate change correct, or mean that anyone who is the least bit sceptical is being conned by these people.

        1. It may be a meta analysis, but it's six years out of date!

          The slide you object to is not meant to be quantitaive. It's a schematic to illustrate how the campaign to create doubt has distorted the perception of what we know.

          You may not have \”disingenuous\” motives, but the people coordinating the campaign most certainly do. You may be happy to play along with that. I, on the other hand, believe the public have a right to know who's pulling the strings.

          1. Give me a break – its wrong cause its 'out of date'. Show me an updated meta analysis that proves the study wrong and ill be convinced, but disregarding work simply because its 6 years old is silly.

            If that logic holds then ALL WORK EVER PUBLISHED IS WRONG. Because all science will one day be at least “6 years old”.

            So why should we take the conclusions of any report seriously if they are to be made redundant by ‘new science’?

            No I do not prescribe by this belief. Each study represents the best knowledge at that time (if done accurately). Sure it may be improved overtime. But unless it is proved wrong, it is not out of date just because it is “6 years old”.

          2. (continued…)
            I’m sure if the conclusion fit your beliefs you would not be so ‘skeptical’.

            I am willing to be proved wrong so I did a google search for meta analysis, and what did I find?


            “This paper presents an update of an earlier meta-analysis (Tol, 2005) of the social cost of carbon. Besides more data and more advanced statistical analysis, this paper offers four results. Firstly, there is a downward trend in the estimates of the social cost of carbon – even if the IPCC (Schneider et al., 2007) would like to believe the opposite. Secondly, the Stern Review (Stern et al., 2006) is an outlier – and its impact estimates are pessimistic even when compared to other studies in the gray literature and other estimates that use low discount rates.”

            1. Same author, known for his low estimates of cost. Note also that it is impossible (or at least very difficult) to value ecosystems and the services they provide. There is a European effort to do that under way, but the link is not to hand. Rest assured it's not alarmist : but you may find the figures alarming.

            2. "known for his low estimates of cost" – so you pick Stern?

              Its a meta analysis, it should cut through that.

              Good point about ecosystems and biodiversity. Keep in mind that climate changes impact on these factors is 'contributory negligence'.

            3. For good order, the latest version of the meta-analysis will be published next month or so.

              The 2004 paper is indeed a bit out of date, but the updated versions do not change the fundamental conclusions.

          3. Also, how can you say the slide is not meant to be quantitaive? It has a graph with axis labelled "Number of Proponents" and "Predicted Impact of Climate Change". Two quantitaive measures. Do you even know what quantitaive means? How can you plot the graph with out quantities? (I guess the only answer is draw a made up line).

          4. "It's a schematic to illustrate how the campaign to create doubt has distorted the perception of what we know."

            This is ironic. The meta analysis of the literature actually suggests the campaign to create alarm has distorted the predicted costs of climate change.

            1. Final paragraph:

              There is a strong case for near-term action on climate change, although prudence may dictate phasing in a higher cost of carbon over time, both to ease the transition and to give analysts the ongoing ability to evaluate costs, benefits, and policy mechanisms.

              Since you provide the study, I take it you support this conclusion and will henceforward support strong near term action on emissions.

            2. Haha one step at a time.

              First, the study says "Strong case for near-term action", not a case for "Strong near tem action".

              Secondly the study is an assessment of the economics, not the science. So presuming the IPCC models correctly predict the physical changes, the damages this may create can be assessed and show a strong case for near term action that can be ramped up overtime. Yes I can most certainly agree with this conclusion.

            3. Go and read my latest post, and the references therein, and then come back for a chat about "campaigns to create alarm".

  7. from the study

    “If we take all studies without discriminating between them, the best guess for the marginal damage costs of carbon dioxide emissions is $5/tC, but the mean is $104/ tC. This difference reflects the large uncertainty combined with the notion that negative surprises are more likely than positive ones. However, there are good reasons to discriminate between studies, and this has a systematic effect on the combined marginal damage cost estimate. It appears that studies with better methods yield lower estimates with smaller uncertainties than do studies with worse methods. If one excludes the studies in the gray literature, the combined marginal damage cost estimate falls further, and so does its uncertainty. It seems as if the most pessimistic estimates of climate change impacts do not withstand a quality test.”

    …..“One can therefore safely say that, for all practical purposes, climate change impacts may be very uncertain but is unlikely that the marginal damage costs of carbon dioxide emissions exceed $50/tC and are likely to be substantially smaller than that.”

  8. Gareth, sorry this got into such a protracted debate. I did not mean to hijack the comments section of this post. I was alarmed at the slides you presented and wanted to point out that slide 14 in particular was not backed by literature.

    Can I suggest in the future where a reader points out a fault you do not treat yourself as infallible? I will do my best to be more diplomatic.

  9. Slide 14 is a very succinct way to illustrate the way the balance of the debate has been distorted. In the context of that section of the talk, it's useful and I make no apologies for using it or defending it.

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