The great climate debate 2009 – Brook vs Plimer

A quick post to let you know that I’ll be ‘debating’ Ian Plimer of Heaven & Earth ‘fame’, tomorrow, in North Adelaide.

The event is hosted by ‘Engineers without Borders‘. Details below:


Climate change debate! Barry Brook will be going head to head with Ian Plimer on the topic “Climate change is man made”.

6:30 pm on the 28th July at Engineering House, Bagot st, North Adelaide. Speakers have been told that they will be debating the topic: “Climate change is man made”. Speaker for the affirmative: Barry Brook. Speaker for the negative: Ian Plimer.

More information here:

The great Climate Debate

Brook versus Plimer: The great Climate-Change Debate

EWB (Engineers Without Borders) SA has organised a debate between two of South Australia’s most out-spoken climate-change scientists – Prof. Barry Brook (affirmative) and Prof. Ian Plimer (negative). The topic of the debate is “Man-made or not?” and will be moderated by Ian Henschke, presenter of ABC South Australia’s ‘Stateline.’ It promises to be a lively debate and it will shed light on some of the ‘finer’ aspects of climate change science.

WHEN: Tuesday, 28 July, 6 for 6:30 pm start

WHERE: 11 Bagot St, North Adelaide

$5 for members, $15 for non-members (funds raised contribute to EWB’s development projects)



I hope some of you BNC readers can make it. In any case, I’ll report back here on Wednesday with a short report on how it all went.

Oh, and I think I’ll be appearing alongside Ian tomorrow morning (Tue 28 July) on radio, ABC 891 morning show with Matt & Dave, so tune in for that also.

In both cases, I’m not sure whether to expect fireworks or fissle…

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By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

49 replies on “The great climate debate 2009 – Brook vs Plimer”

Dear me, I didn’t realize the veracity of climate science was based on the geographical location of its authors. Imagine had Einstein said “I don’t live in Canbridge, I’ll leave the debate over absolute time to the English physicists”.


Dear me, you obviously can’t read the title of this thread. It is about a face-to-face debate. I’m sure Lindzen will get his traditional ‘debate’ via the traditional means — via a rejoinder published in the scientific literature.


I was suggesting that in your debate, you could start by explaining why Lindzen is wrong, since he claims the negative cloud-feedback evidence points towards a climate sensitivity of 0.5C. If you cannot explain where Lindzen is wrong then there’s not much to debate is there?


Asking a colleague from NCAR, this is what he said:

“I note that he cites Lindzen and Giannitsis, which was shown to be flawed …

Wigley, T.M.L., Ammann, C.M., Santer, B.D. and Raper, S.C.B., 2005: The effect of climate sensitivity on the response to volcanic forcing. Journal of Geophysical Research 110, D09107, doi:10.1020/2004JD005557. (see:

…and his iris idea, which has been demolished in the literature.

He also fails to explain why other estimates of sensitivity based on observed data are wrong. Also, some of the models do not include all forcings so cannot be compared directly with observations. The effects of ENSO are not factored out, nor does he consider that model results may reflect ENSO errors and not be relevant to longer time scales.

Clever stuff — but all his previous clever ideas have been subsequently shot down.”

Regarding that point on other estimates of sensitivity, one of the most robust is the Quaternary data, which indicates a fast-feedback sensitivity of 3 +-0.5 C, and this is the evidence I’ve looked at most (being closest to one of my areas of research interest). It seems quite convincing (with ice sheet albedo providing a similar forcing).


Hmm my post above was meant to be a reply to Barry’s last post. OT, is your NCAR colleague Tom Wigley by any chance? I see from his bio he studied Mathematical Physics at Adelaide University, so there’s the Adelaide connection. I too had the good fortune to study Mathematical Physics at Adelaide before Bert Green, Angus Hurst and Peter Szekeres retired (Szekeres was my honours supervisor. Green and Hurst had retired by then but I took undergrad courses with them).



There are people who have pointed out problems with Lindzen’s point of view. You can start here: Now, you can attack the attackers, and we can attack your attack on the attackers. So in the end, it’s really going to be up to you which set of arguments you are going to believe.

The number of Lindzen’s in the world is very small. Lindzen’s arguments have not persuaded most scientists.

So it’s really up to you who you want to believe…Lindzen or everyone else.


I’m baffled into why you’re debating him. Generally speaking, debates are exactly what denialists love, as public rhetoric defeats logical argument any day of the week. (Beware the Gish Gallop.) On the flipside, take a look at how few of them are actually willing to commit to a bet – as soon as their own money’s on the line, all of the big names button right up.

That said, if I weren’t clear on the other side of the world, I’d be in attendance. Any chance of a transcript, recording, or video?


Don’t know about transcript or video yet — unfortunately not likely. My style won’t be (predominantly) to ‘defend’ the mainstream view. It will be to ask Ian various questions about which I’ve very curious to hear his answer. I think this will serve a purpose (if I didn’t think so, I wouldn’t have agreed — I acknowledge that ‘debate’ over the fundamental science is pointless).


Good luck, although I really have reservations about live debates about science, even compared to blog debates that allow for looking at graphs, checking out referenced data, etc. Confusion is a lot easier to create than clarity.

Here’s one example of a useful blog debate. Search for “John Mashey” post, and then a few posts later, comments by one of the participants, Bob Ryan.

I am curious: can you say more about the format of this debate?


Not sure of the format — I think it is me for 5 min, then Ian for 5 min, then the floor is opened to Q&A with the audience. The less formal presentation and the more chance to get at some core issues, the better, IMHO.


Turns out that Ian couldn’t be contacted for the ABC 891 Matt & Dave interview this morning. BUT — they are interviewing me, on nuclear power. So for those in Adelaide or who can listen via the net, I’ll be speaking at just after 9am today, ACST.


I agree with Brian D. and John Mashey regarding the usefulness of `debating’ denialists. However, I will be there, and I’ll be interested to hear both your questions and Plimer’s answers. I suspect, however, it will be a rather frustrating experience for you.

(My other interest is in seeing how many different rhetorical and obfuscatory tricks are used…)



Sitting here in London let me wish you the best of luck.

I do think its a zero sum game debating denialists, but you are most probably better at debating than me. However, I guess you have thought through and discussed the ways not to get sucked into their lines of thinking. Just don’t, don’t get sidetracked on creationism with Plimer.

Hmmmmm, just thinking about it, perhaps you can on from this to debating Monckton……. sorry, just a thought.

Is it going to be put on U-tube so i can watch it?


Barry has already comprehensively wiped the floor with Plimer at a debate for the Sceptics Society of SA, so I have every confidence he will do the same at this latest debate. From what I have seen and heard Barry “thinks on his feet” therefore we don’t need to be apprehensive for him.
Go get ’em Barry!



You will be “curious to hear his answer”- why, if you know the answer get on the front foot and state it. The CO2 alarmists propaganda campaign has ridiculed science.

Public debate is a political side show, ethics, integrity, and mutual respect of you and Plimer will take a hit. None in the audience will understand the physics and mathematics necessary to “prove the answer”, doing it any other way is lowering yourself down to an Al Gore, a Hollywood actor and a science clown.

The politicians are running a muck, they are airheads on this matter; vested business and financiers are salivating, the matter is now serious, but “genuine and relevant scientists” have been overwhelmed by their own colleagues who have turned feral for politics and/or money.

From your position take the high ground, push for funding “unrestricted research into the climate mechanism”; the hypothesis of man made CO2 emissions causing serious global warming effects is looking sick, nature is prevailing, IPCC has tinkered too much with it’s argument, the best of climate scientists is required.

Undoubtedly your blog cheer squad would not agree with a responsible approach


It’s nice to have a rational ‘cheer squad’, I agree. I’ll be curious to hear is answers to the slew of apparent contradictions in his book. Given that he seems to simultaneously believe bunch of contradictory things, I’m curious to see which one he ends up gravitating towards. Should be interesting.


Barry, I too would love some audio or whatever you can get from this event. Check out this interesting twitter tweet I got in response to mine about this event:

@fang @presidentdalby Even if you can’t hear Brook v Plimer, you can hear Plimer on @medvedshow today at 5:00 Eastern #climatechange #plimer



Hi Barry – good luck with the debate. I share some of the misgivings other people have with debating such people. Engaging them in debate somehow seems to legitimise their position and you can rarely ‘win’ an argument with them. Also the audience has to educated enough to understand that you will be presenting peer reviewed science and he won’t. To most people all science sounds the same so when Pilmer says temperatures have remained flat for the last 10 years for instance the audience has to know that this is against the scientific evidence or accept your authority over his. It is a no-win situation however I applaud your efforts to communicate climate change science to the wider community.


Brian has said what I would have, so I’ll echo that.

Pity if there is no recording of the event though. Debates are performance rather than intellectual exercises, so I am very interested in the analysis, particularly if Plimer Gishs.


Stephen Gloor (post 15) said;
‘I share some of the misgivings other people have with debating such people. Engaging them in debate somehow seems to legitimise their position and you can rarely ‘win’ an argument with them.’

I remember an old Catholic priest using a similar argument to this so as to justify not debating atheists/dpubters. At one stage, congregations couldn’t even read the Bible lest they might ‘misinterpret’ the message (see climate audit re data from the met office).
Unless God appeared tomorrow before all or CO2 was proved conclusively to cause CC, then debate is a natural method of discourse.
Love to see a transcript because some of Plimer’s work is ‘sus’.


Okay, the debate has come and gone. I haven’t seen Plimer in action before and he is, as befits an experienced lecturer, smooth and polished. Its impossible for me to judge who “won” the debate but I suspect Barry, that you shouldn’t have spent time explaining the IPCC process to that audience and should have gone straight to the evidence. Plimer manages to simultaneously espouse a love of evidence while preaching a conspiracy theory about everybody except him ignoring evidence. A few questions indicated more than a few conspiracy theorists in the audience.

It soon became obvious (to me anyway) during Plimer’s presentation,
that he doesn’t have the foggiest about how climate models work and it also became clear that he has a univariate brain while claiming to be holistic in his approach. The idea that CO2 could be a response during some warmings and a forcing during others seemed beyond him. He wants it to always play the same role despite huge differences in contexts.

What infuriated me totally about Plimer is his off-hand dismissal of change as harmless and his seeming inability to understand that it isn’t just humans at risk from the impacts of large climate change. Barry did a good job trying to illustrate the wider impacts, but it was water off a ducks back. For a professed student of history, Plimer seems either pig ignorant or totally unconcerned about the suffering caused by changes to climate status-quo … for example, by monsoon failures. “We will survive climage change” he says with a smile. Human species survival isn’t the issue. Its not just all about humans and its not just all about what happens at a species level.


You make some broad sweeping statements here Geoff, verging on the insulting – any chance you can back them up? I’m thinking about conspiracy theorists in the audience (how do you know and what do you mean?); Plimer’s conspiracy theory (ditto); and the monsoon failures (what do you know about this and what empirical observations can you provide to substantiate this assertion).

I suspect that Plimer is not pig ignorant but rather that you disagree with him. You do not help in getting your point across with this type of language.


“I suspect that Plimer is not pig ignorant but rather that you disagree with him.”

The two aren’t mutually exclusive, John Smith. Just saying.


Firstly, John, good on you for coming to the aid of the young guy with the “denier” question. Clearly Plimer had every right to be offended by the question, but should have said so and moved on. Methinks he did protest too much.

On conspiracy. The question regarding biases in the kind of research which gets published got quite a few nods of agreement in parts of the audience. I think the proposition that global warming science would be found wanting if not for editorial bias in the peer reviewed journal is a conspiracy theory and rubbish. Which is not to deny that funding biases may not be operating. I have little evidence for or against a funding bias, but have sat on committees reviewing research and seen funding biases a plenty. This is quite different from an editor choosing to publish a bad paper or choosing to reject a good paper.

On monsoons. If ENSO is altered in either frequency or intensity then changes in monsoon behaviour could bring drought in SE Asia

Mark Bowen in “Thin Ice” surveys some of the evidence of past extended El-Nino conditions which have had massive impacts in South America.

Plimer discussed historical climate change like it was changing curtain colors. I hope he is simply ignorant (pig or otherwise) and not uncaring.


Just clarifying my second paragraph … written in haste. I have seen
what I think are funding biases in health/agriculture research
over many years. Have I robustly analysed protocols to check
my gut feeling? No.


Thanks Geoff. I’m not sure where “caring” comes into a science debate, either in relation to Plimer, or in the tipping point article you referenced, as in “A significant number of people care about the fate of the system . . “. I suspect that we all care about the fate of the system. Caring is an affective term and depends somewhat on interpretation. I cannot see its relevance to science.

My original question, based on the certainty and vehemence of your response to the Brook-Plimer debate, was the monsoon failures you mentioned, particularly with regard to what empirical observations can you provide to substantiate this assertion.

The tipping point article, while very interesting, contains no empirical evidence, only conjecture. Is there any empirical measurements or observations to substantiate your bold statement.

“Firstly, John, good on you for coming to the aid of the young guy with the “denier” question.” I don’t know what you mean.


Do I have you confused with somebody else? Were you not at the Plimer debate and stood up to defend a young guy who Plimer harranged over a question? I don’t know him well but I’m pretty sure the guy who did this is really called “John Smith”, but perhaps you are just using the name as a blog handle.

Monsoons and tipping points. “Thin Ice” a book, has plenty of history of civilisations along the west coast of South America who suffered and ultimately died out because of long El Nino periods. The Lenton paper isn’t just a vague guess. I referred you to a publically available website. The full paper is on PNAS and referenced at the bottom of the page. I’ve just checked and it is open access and provides more information on why it considers ENSO shifts likely:

On caring. Some scientists, like some non-scientists don’t care about the fate of people or other animals and you don’t have to be caring or compassionate to do brilliant science. But I don’t care for such people. Perhaps my assessment of Plimer was hasty, but it wasn’t just based on that debate, but on other writings and media appearances. In any event, I think you are right and I will try to refrain from intemperate comments in future.


Guy, I’m hoping it will be available shortly, however, I fear there may have been a problem with the audio equipment. But as a backup, ABC Lateline caught the first hour or so of it, so we (The Environment Institute) might alternatively be able to get a copy of that (the audio at least — it was also filmed for this portion — most of the debate minus the Q&A). I’ll update here when I know more.


Wigley, T.M.L., Ammann, C.M., Santer, B.D. and Raper, S.C.B., 2005

This looks like yet another paper in the series “sensitivity is proportional to 1 / (1-f) and we can’t rule out f close to 1 so sensitivity could be large”. Dig deep enough and you find this same uncertainty underlying every poorly-constrained sensitivity estimate. It doesn’t mean sensitivity is likely to be high, it just means we have to constrain it by other means. BTW, Other papers (eg Douglass and Knox) tell a very different story about sensitivity from volcanic eruptions.

…and his iris idea, which has been demolished in the literature.

No it hasn’t. And he hardly relied on it in the paper. At its loosest the “Iris idea” is nothing more than negative cloud feedbacks.

He also fails to explain why other estimates of sensitivity based on observed data are wrong.

Which other estimates of sensitivity based on observed data? I’ve not seen anything that did not suffer from the aforementioned difficulties (except, as you say, the estimates based on the Quaternary, but they have their own problems – I’ll get to that).

Also, some of the models do not include all forcings so cannot be compared directly with observations.

Maybe, but every model gives the opposite sign to the data.

The effects of ENSO are not factored out,

Maybe. But again, every model gives the opposite sign to the data.

nor does he consider that model results may reflect ENSO errors and not be relevant to longer time scales.

Again, ENSO is unlikely to be the models’ saviour when every single one gets the wrong sign. Your NCAR friend needs to back up his claim.

Clever stuff — but all his previous clever ideas have been subsequently shot down

All his previous clever ideas have been subsequently shot down? Oh sure, they hand out MIT professorships to idiots all the time.

On the Quaternary studies. The fundamental problem with those studies is they assume sensitivity is independent of climate state, viz: a 3C rise for doubling of CO2 (factoring out ice albedo) over 100,000 years does not imply climate sensitivity today is 3C. At the start of the temperature rise the Earth is colder (and drier) – there could be far greater positive water-vapor feedbacks from increased forcing than at the end (where we are now) when the Earth is already warmer and wetter. Integrating over 100,000 years does not tell you today’s sensitivity.


Barry, I hope it went well.

But then, many people prefer sweet lies to bitter truths …

Is there an MP3 available of the debate? If positive, can I get a copy?




New Climate Crock of the Week – Polar sea ice melt and permafrost thaw. Those of you wondering if the pseude-sceptics are right should check out all of this excellent series.


Try Dr. Roy Spencer for recent articles about climate feedbacks. He as well as Lindzen shows that feedbacks are neutral or negative. Also, more radiation is escaping or being reflected to space than the models predict.
Don’t forget, Dr.Robert Carter, “Three realities of Climate Change”.
Finally, in a new paper, “Small fluctuations in solar activity, large influence on the Climate”
Researchers from the USA and Germany have now, for the first time, successfully simulated the complex interaction between solar radiation, atmosphere, and the ocean. As the scientific journal “Climate” reports in it’s latest issue,Gerald Meehl of the US National Center for Atmospheric Research and his team have been able to calculate how the extremely small variations in radiation brings about a comparatively significant change in the System “Atmosphere-Ocean” It blows away the IPCC and CCSP arguments that the sun is a bit player in climate compared to CO2


Click to access dessler09.pdf

And Meehl et al. propose a mechanism that may explain the mechanism for the known small effect. It doesn’t change the size of the effect — small, compared to CO2 forcing.

Jim, you really should cite your sources. You’re quoting from what, CO2science? If you’d look at the actual papers it would be much harder to fool yourself, or anyone else.

We’d like to be able to rely on you for facts.


Oh, Jim’s apparently quoting Morano; Greenfyre tags that one with many links worth reading.

Here, Jim, this is how:

“I have a paper [PDF] in this week’s Science discussing the water vapor feedback. It is a Perspective, meaning that it is a summary of the existing literature rather than new scientific results. In it, my co-author Steve Sherwood and I discuss the mountain of evidence in support of a strong and positive water vapor feedback.
… just about everybody now agrees water vapor provides a robustly strong and positive feedback. Roy Spencer even sent me email saying that he agrees.”


“how the relatively small fluctuations of the 11-year solar cycle can produce the magnitude of the observed climate signals in the tropical Pacific associated with such solar variability.”




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