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What's all this then?

The blogospheric dissection of the papers by Spencer and Braswell and by Dessler continue apace. In fact the pace is a bit of a problem, as I have been left rather behind - radiative physics is an area I need to get up to speed on. This is a pity because it looks as though today's excitement is all going to be focused the effect of clouds on the earth's energy budget.

Firstly there is this comment by Bart at CA. Then there's this post by Tallbloke, which is essentially just a reposting of a comment by Bill Illis at WUWT.

The Bill Illis/Tallbloke piece seems rather more straightforward to me - if I understand it correctly, it shows that the variability in the amount of heat escaping the earth is driven to a large extent by changes in cloud cover. As one commenter puts it:

But the [climate models] only assign a single, constant value for all clouds, at all latitudes, for all periods of day and night, for all seasons of the year, across all elevations for all values of humidity and rainfall and percent CO2.


I can see that this is a problem, although perhaps I haven't quite got my head around the implications yet.

The Bart comment at CA is, however, more tricky and I haven't made head or tail of it yet. Given that there seems to be general agreement that it may be significant, maybe readers here can explain.

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Reader Comments (162)

Hi Mac

I've already answered your question about Tamin's scientific integrity.

If you look back at the relevant thread, my equation "climate scientist = green activist = fiddled science" was a characature of how many of the opinions here come across, to my perception. Several people responses to say that this was too simplistic, which I was pleased to hear, but someone else (I won't name them - you can check for yourself) did post something which pretty much said exactly what I'd characatured earlier!

So my question to you is: do you think my characature is a fair reflection of your own opinion? If not then I would be very pleased to stand corrected, and will even apologise to you for making unfair assumptions.

Oh and BTW I don't think "greenie" necessarily means "activist" anyway. I think you are going out looking for things to criticise, instead of being prepared to engage in the content of a discussion. I believe "ad hom" is a phrase sometimes used round here in that context.

Sep 12, 2011 at 6:52 PM | Unregistered CommenterRichard Betts

Sep 12, 2011 at 5:12 PM | BBD

Well said. Too many people (although not everybody here, I should point out) assume that acceptance of the basic scientific evidence (that humans exert some influence on climate) automatically implies agreement with a particular view on energy policy. (This is not restricted to the sceptic community, by the way).

The sooner we can separate the two the better. Then we can have a sensible conversation about the science, including its uncertainties, without assumptions about motivations.

Sep 12, 2011 at 7:11 PM | Unregistered CommenterRichard Betts

There is no need for anyone to agonise over whether humans influence the climate. That ought to be a platitude since everything in the climate system ought to be regarded by default as having some influence. The questions of interest are 'by how much?', and 'in which direction?' for any specific measure, e.g. air temperature, sea temperature, precipitation levels, etc etc etc. Briggs has a good post on this here:

It is a little bit like the old widsom about hypothesis testing in statistics - we generally know the null hypothesis is wrong, but we may not know, or be able to demonstrate, in which direction and by how much. Those are the interesting questions.

Sep 12, 2011 at 7:32 PM | Unregistered CommenterJohn Shade

Richard Betts; Philip

Yes. Anti-nuclear renewables boosterism isn't exactly the high road to decarbonising the electricity supply, is it? (I do wish someone would mention this to WGIII).

I too hope that Tamsin decides to contribute here. We could all learn from discussion with someone expert on the subject of modelling and - better yet! - uncertainties in modelled projections. But as we've just seen, she will need a thick skin and saintly patience.

Sep 12, 2011 at 7:41 PM | Unregistered CommenterBBD


Please step back and take a deep breath. There are far too many threads being dominated by the same few voices.

Also, I expect all visitors here to be treated with courtesy. When people come here to the lion's den, as it were, it is a sign of a willingness to engage and should be treated as a clear indication of their bona fides. I will not tolerate visitors' bona fides being called into question without good cause.

Sep 12, 2011 at 7:53 PM | Registered CommenterBishop Hill

John Shade

The questions of interest are 'by how much?', and 'in which direction?' for any specific measure, e.g. air temperature, sea temperature, precipitation levels, etc etc etc.

Indeed. Have you been keeping an eye on this season?

Sep 12, 2011 at 7:57 PM | Unregistered CommenterBBD


Anti-nuclear renewables boosterism isn't exactly the high road to decarbonising the electricity supply, is it? (I do wish someone would mention this to WGIII).

I recommend you try to sign up as a reviewer of the WGIII First Order Draft - then you can tell them yourself!

Evidence-based comments such as those that you provide here will be exactly what they need.

Sep 12, 2011 at 9:33 PM | Unregistered CommenterRichard Betts

RB This is a legitimate line of debate.

We have had a series of papers that strongly suggest that climate models have over-estimated the amount of warming that is observed.

Will climate modellers 'correct' the models (and not just reset them) so that modelled outcomes match observations? That is a matter of concern.

In Tamsin Edwards we have a climate modeller who is also a self-confessed 'greenie'.

This conjours up a different question. Can a climate modeller who is also a 'greenie' correct the models that in all probability runs counter to that person's beliefs?

I don't think they can!

This brings us back to the RB's original 'denier' equation;

climate scientist = green activist = fiddled science

Perhaps we can amend the 'denier' equation to form an 'activist' statement.

climate scientist & green activist => consensus science

I think this represents a reality in parts of the climate science community. We have people at the heart of the climate change debate who are on an ideological mission, they cannot separate their beliefs from scientific practice. Everything is geared to spread, bolster and protect the consensus. No data, no observation will shake their faith in the consensus, the models have become sacrosanct.

Until activism is driven out of climate science no one can be certain that consensus science is no more than fiddled science.

Sep 12, 2011 at 10:01 PM | Unregistered CommenterMac

John Shade

Apologies. Bad tags in my previous:

The questions of interest are 'by how much?', and 'in which direction?' for any specific measure, e.g. air temperature, sea temperature, precipitation levels, etc etc etc.

Indeed. Have you been keeping an eye on Arctic ice melt this season?

Sep 12, 2011 at 10:08 PM | Unregistered CommenterBBD

Bishop, you've been taken over. You've been infiltrated. Your blog is now a talking shop for the alarmist.
Please send me an email when you have reinstated management control over your own blog.

Sep 12, 2011 at 10:09 PM | Unregistered CommenterDavid Porter


I agree the alarmists come to preach, deflect, conflate and decry. To them we are still all "deniers".

Sep 12, 2011 at 10:16 PM | Unregistered CommenterMac

a pet peeve of economics, every month or quarter of year, major governments release figures on a mass of aggregate figures - employment, blance of trade, growth, gdp, inflation, stock levels etc etc. These numbers are controlled by official processes.

An person interested in these numbers can use whatever knowledge she possesses to make an interpretation. There are also numerous academic and commercial bodies churning these numbers through their models. But the general idea is that the more data you have, the better your analysis could be. As a result we can guess what is happening in the US, in the UK, in all the Eurozone countries, Japan, Hong Kong, Singapore and..........

Compare with climate science.

Four indices of a global temperature which all come up with slightly different measurements, with no regional brreakdown.

One observation of CO2 levels.

A blog obsession with Arctic ice - as if the ice sheets in the Himalayas, the Antarctic or Greenland do not matter. And this obsession with Arctic ice has numerous datasets, all incompatible and measuring different things - volume/extent/........

OK, this might be the only available data but with data such as this, it is not possible to discuss climate change nor what should be done to either combat or adapt to it.

No one seems to want to admit to this. If you do mnot have the data, discussion is futile and understanding is.......lacking

Sep 12, 2011 at 11:00 PM | Unregistered Commenterdiogenes

Richard Betts Sep 12, 2011 at 7:11 PM

"The sooner we can separate the two the better. Then we can have a sensible conversation about the science, including its uncertainties, without assumptions about motivations."

Extremely well said Richard, many thanks and I truly mean that, just wished you and others had said so when it mattered before 2008.

I am afraid it is now too late, the politicos now control the "scientific" outcome, unless the climate science community can find a way of letting them save face?

Appeasement has a time line beyond which it becomes intransigent, I fear that we have passed the line.

Sep 12, 2011 at 11:23 PM | Unregistered CommenterGreen Sand

O/T Bish, but have all the regulars went comment/slagging mad? why!!!!

as to Bart, like you have no idea, reminds me of the VG (i think) kerfuffle.

Sep 12, 2011 at 11:26 PM | Unregistered Commenterdougieh

Sep 12, 2011 at 10:01 PM | Mac

I don't use the term "denier" and indeed actively discourage others from doing so, as is a matter of record on Twitter in a discussion between myself and David Roberts from the Grist blog.

Sep 12, 2011 at 11:46 PM | Unregistered CommenterRichard Betts

Richard Betts,

Are you the MetO's designated blog evangelist? By that I mean is it part of your job to explain your beliefs to non-believers?

Serious question.

Sep 13, 2011 at 1:11 AM | Unregistered CommenterBilly Liar

Wow. Yesterday, I was just some anonymous guy posting to a thread on a blog. Today, I'm some anonymous guy who's pseudonym has reached across the pond. I'm kinda' pseudo-famous!

The respondent who wrote "I think Bart is an electronics engineer" is correct to some extent. I am an EE who has had a fairly lengthy career in control systems design and analysis. It has really bothered me seeing analysis of such an important climate subsystem being done in a completely inappropriate manner. Linear regressions on a phase plane graph constructed from signals with nonlinear, dispersive phase relationships make no sense.

Yes, the system is undoubtedly nonlinear, but most nonlinear systems operating in a "narrow" region can be analyzed using linear systems theory. And, lo and behold, a more appropriate analysis reveals a standard 2nd order linear systems response, with a most decidedly negative sign (-180 deg or less phase shift at low frequencies). At the very least, that makes the score in the Spencer-Dessler clash 1-0 in favor of Spencer.

The steady state sensitivity is about -9.5 W/m^2/degC, but this corresponds to sensitivity of the IR exiting through the clouds. A more important measure would be to transform that into how much incoming solar radiation would be reflected by the increased cloud cover. I do not know how to get the information to do that - I'm a control systems geek, not a climate scientist. Hopefully those who do will take notice of the result and determine just how much of a thermostatic effect is exerted by this feedback.

Sep 13, 2011 at 1:28 AM | Unregistered CommenterBart

Bishop, think of a water bed. The top of the bed has a latex layer with water underneath.
You could make a depression with you hands and then quickly remove them. The depression would bounce up and the edges will drop, then you will have a series of smaller and smaller oscillations, until the surface is again flat.
Or you could do it another way, grasp the center of the bed, lift the surface and let it go; again you will have a series of smaller and smaller oscillations, until the surface is again flat.
Now the periodicity of the oscillations will be the same if you disturb the surface by pushing or pulling. In fact, no matter what you do you will get the same frequency of oscillations. The periodicity of you bed is a function of the density of the liquid inside (water) and its size. You can use a bigger bed and get a longer oscillation or change the liquid; the less dense the quicker the bed will oscillate.
Many things, like pendulums, strings (think piano wires) or bridges have natural frequencies.
Bert has looked at the response of the ocean to heat changes (clouds) and looked at the oscillations that follow. In a mathematical model he is trying to make waves in his bed, he is both pushing and pulling it, then looking at the frequency of the response is the same as he sees in real life.
The easiest way to think of it is like this;
Earth gets hot (pushing the bed), heat stored in top of ocean, water evaporation rate above average, clouds increase above average, sunlight hitting ocean drops, heating of top layer of ocean drops, full ocean oscillation takes 5 years.
Earth gets cool (pulling up cover of the water bed), heat stored in top of ocean radiated and not restored, water evaporation rate drops below average, clouds decrease below average, sunlight hitting ocean rises, ocean circulation slows, full ocean oscillation takes 5 years.

Sep 13, 2011 at 2:05 AM | Unregistered CommenterDocmartyn

Billy Liar


Sep 13, 2011 at 7:29 AM | Unregistered CommenterRichard Betts

Bart - typical Control Engineer always trying to the close the loop (engineering joke)

As someone, myself, who has dabbled with designing 2nd order electronic systems I am very impressed by your analysis.

Sep 13, 2011 at 9:18 AM | Unregistered CommenterMac

RB - "I don't use the term "denier"" .........................but, Tamsin Edwards does!

I would argue that any 'objective' scientist, your description, who uses the "denier" word is indulging in activism, and hence is NOT behaving objectively. I would argue further that the use of the "denier" word in scientific blogs is a deliberate ploy to divide and rule the climate science community.

Personally, I doubt Tamsin Edwards can separate her 'greenie' beliefs from the science she practices. You can't have a sensible discussion on science when to her we are all 'deniers'.

If as you say you actively discourage others from using the 'denier' word, what words of discouragement would you have for a self-confessed 'greenie' like Tamsin Edwards? I would be interested in what you would or would not say.

Sep 13, 2011 at 9:34 AM | Unregistered CommenterMac

On this: "A more important measure would be to transform that into how much incoming solar radiation would be reflected by the increased cloud cover. I do not know how to get the information to do that - I'm a control systems geek, not a climate scientist."

I don't think I was interpreting what the quantities mean correctly. But, like I said, I'm no climate scientist. All I know for sure is I have determined that something the mandarins assumed was a positive feedback is, instead, strongly negative.

Sep 13, 2011 at 10:26 AM | Unregistered CommenterBart


At the request of biologist ECEgeorgia, one davidmhoffer - in posts from September 12, 2011 at 11:19 pm to September 13, 2011 at 12:15 am - has prepared the first nontechnical summary of what Bill Illis contribution to the Spencer-Desler debate might be.

Please start here.
[HOT LINK not previewing.]

To cut to Hoffer’s chase:

“Spencer and others have long argued that clouds dominate earth’s climate variations to the point that other factors such as CO2 are simply insignificant by comparison. Illis appears to have simply done the obvious, which is to compare the variations in earth’s radiance to space over all to variations in radiance due to clouds. The result?...MOST of the variation is due to clouds. There’s hardly anything left for CO2…or methane…or [anything else.]

“So…Co2 is insignificant (like we knew 20+ years ago) compared to clouds, clouds are not a major positive feedback and are probably even a negative feedback, making any additional cloud
cover from extra water vapor a cancelling effect on what ever warming CO2 actually causes.”

To put in other terms, let's begin with Richard Lindzen’s hypothesized ‘adaptive iris effect’ to explain how clouds might naturally vent CO2-accumulated energies harmlessly into space. With Spencer and now Illiss, after Dessler, we seem to have arrived at a data-driven ‘infilling of the gap’ between weather and climate change. Or at least a decent sketch.

My worry comes from the limited radiant resolution from the satellite data over a quite limited time period. Here there exists holes. It is one thing to doubt AGW-theory; now we have well-founded reasons to doubt AGW-skeptic data that answers it. To invoke Shakespeare, Uncertainty? “Twas ever thus” the fountainhead of continuing scientific research projects!

But the upshot is clear. If we can have more accurate data from satellites, better measurements from short-time periods of only many years ought to be able to narrow these uncertainties rather swiftly. Devilish problems like planetary radiative transmission involving clouds, against a backdrop of rising CO2,
may be an "uncertainty monster" not living for long.

Sep 13, 2011 at 11:45 AM | Unregistered CommenterOrson

Lest we forget:

IMO, none of these papers are of particular scientific interest, although they have become important in the public debate. The broader issue is that we need more papers comparing satellite observations to climate model simulations, and need to design better ways of using these data to evaluate processes of relevance to cloud feedback.

Bottom line: S&B and LC papers do have flaws, as discussed on previous Climate Etc. threads. Dessler (2011) adds relatively little to this debate. None of these papers are particularly useful in evaluating the sign or magnitude of the cloud feedback.

Nevertheless, all this stuff is like crack cocaine for the climate blogosphere :) .

Sep 13, 2011 at 11:58 AM | Unregistered CommenterBBD

yes, don't think people. just listen to judgements passed on papers after days they've been published and unscrew your brains and keep it aside.

God to bed Bishop Hill readership, the consensus is in control.

Sep 13, 2011 at 12:11 PM | Unregistered CommenterShub

BDD: "None of these papers are particularly useful in evaluating the sign or magnitude of the cloud feedback."

OK, Then tell us where the feared energy is coming from, if not from cloud amplification? IF none of these (above) analyses can find it, using the best empirical tools we have, where do you hypothesize it will be found?

Sep 13, 2011 at 12:53 PM | Unregistered CommenterOrson


I have followed your arguments on Climate Audit with interest. I am a working geophysicist trained in signal processing so I am able to follow your arguments closely, especially the detailed conversations with people such as Nick Stokes concerning the intricacies of the symmetry/non-symmetry in the real and imaginary parts of the FFT/iFFT. I understand the convolution arguments thoroughly, the significance of the amplitude and phase spectra in the context you have used it and so on. You clearly know exactly what you are talking about. I am not familiar with the use of these frequency domain techniques for evaluating feedback systems (I am a geophysicist, not an EE, so I will have to read up on this) but your results are so simple and they are remarkable. The 180 degree phase shift looks unequivocal as indicating the feedback due to clouds is negative. Like you I am not a climate expert like Lindzen, Spencer or Christy to know about the magnitudes or the significance of this in understanding long term climate behaviour.

What I do know is that the CO2 effect is too small to give the alarming predictions of the GCM's without also incorporating a positive feedback mechanism with water vapour. The models are currently diverging from reality and seem poor predictors on a decadel scale. You have provided a neat, simple analysis based on well established methods to demonstrate that with the data available from satellites a standard analysis strongly suggests a substantial negative feedback due to clouds.

Well done sir, if this analysis is carried forward by the likes of Lindzen, Christy and Spencer and is found to be correct then the little nugget you have discovered may turn out to be a gamechanger for understanding clouds and climate. Well done!

Sep 13, 2011 at 12:59 PM | Unregistered CommenterThinkingScientist


If you are interested in a synopsis of Stoke's thinking wrt Bart's comments, you will find it on his blog here.


OK, Then tell us where the feared energy is coming from, if not from cloud amplification?

It comes from water vapour amplification (positive feedback). There is a great deal more water vapour in the atmosphere than cloud. Are you missing the point here? (BTW, that was Judith Curry in the quote, not me).


Could you possibly stop baiting me? Failing that, at least do it constructively, with an actual argument.

Sep 13, 2011 at 1:13 PM | Unregistered CommenterBBD


<waves cheery hello!>

I'm sorry that you have this impression of me. I think Bish and Barry Woods would vouch for me: that I am not trying to "divide and rule", that I no longer use the word denier, that I am now careful not to advocate particular policy decisions.

It's true that I wrote "greenie" on my (light-hearted) interview on High Heels in the Lab. But that was meant to be a short-hand for concern about sustainability issues, including: landfill, availability of resources, habitat loss, farming efficiency, ozone depletion. It does not mean that I have pre-formed ideas about what action should be taken, or not taken, with respect to AGW and energy policy.

Primarily I am a physicist: one that takes science, impartiality and transparency extremely seriously. In fact, to that end, I am in the process of entirely re-writing, at great time expense, all my analyses in free software tools (e.g. Climate Data Operators, R) with a view to sharing my code (on a personal website and in journal supplementary material) and climate simulation data (on the BADC website) for others to view and reproduce. I am also planning a couple of guest blog posts about my research and hope to expand on this with plain English summaries of all my papers that are currently in preparation when they are published.

Talking to Bish and Barry, and on occasion others, is helping me to understand the concerns of the sceptic community (or non-alarmist, or other related names/groups). I'm still learning...

I do apologise for my use of the word denier in the past. When I wrote that interview reply I put quotes around it, thinking that was sufficient to show it was other people's term. But since talking to Barry et al. I've stopped using it completely.

Best wishes,


Sep 13, 2011 at 1:36 PM | Unregistered CommenterTamsin Edwards

TS - with Bart closing the loop it implies that change can only happen if there is a 'controller' fiddling with the inputs or that the behaviour of the system has changed. Analysis in the frequency domain gives additional insight on systems and processes. Bart should be encouraged to take this analysis forward.

Sep 13, 2011 at 1:36 PM | Unregistered CommenterMac


I would also agree with all your 'green' concerns above they are mine as well, I could even add a few. I'm pretty green save energy, care about poluttion in the environment(non co2 kind) recycle, reuse, save energy, I even freecycle

I think many climate scientists have passively absorbed the green lobby groups pr that sceptics' are 'anti-science' 'deniers' and don't care for the environment line without much thought, IN THE PAST and just have this cliche of 'sceptics' of some republican, ignorant of science,oil swilling creationist evil exxon funded capitalist in their minds..

Many I think still do... without every really thinking about it, oblivious to Climate Audit, or Bishop Hill, or Watts Up (robustly american)

The green groups can be very emotive and are on a mission 'to save the planet', and just assume that anybody that ask questions, has a 'motive' and treats them with suspicion.

When in fact, many of the sceptics are very concerned for both the environment and the state of science..

If you notice, I've discussed many issues with scientists, and on occasions I feel they come across as 'superior' and condescending, without having actually looked at the issues for themselves.

ie "97% scientists believe" then someone points out the actual flaws in the survey, or so badly worded sceptics would be agreeing. But it has just been used as a soundbite to promote policy & close down debate.

or another says on updating the proxies, aren't the trees cut down, and Bishop Hill explains, core samples

Or others talk about the climategate emails, haven't looked for themselves, etc based on what the media reported .. or talk about issues, without informing themselves of the other view. Ie Prof Judith Curry trying to persuade other climate scientists to read the Hockey Stick Illusion, to be met with derision.

THIS is CHANGING.. thanks to people like Prof Judith Curry, Paul Dennis Prof J Jones and Richard Betts and yourself now Tamsin, people are talking, discussing the issues, AND MOST IMPORTANTLY getting to know each other and hopefully respect each other, getting past pre-conceptions.

I could not (nor would I ) call any climate scientist I know an Alarmist, because I know them.
nor as they know me a little, would they slip into a pre-conception of dismissing me as an anti science denier

To many sceptics, climate scientists have been turning a blind eye, deliberately.
But personally, I think not..

I do think most climate scientists,trust other scientists and are just busy getting on with their lives, bills, mortgages, life, children, etc. I've a friend that is a 'climate scientist' and who is just to busy to engage in blogs, 3 kids (like me) and just permanently in a rush.

DougMcneil linked an article on twitter today that Richard Betts wrote for the BBC

I thought WOW,
this is what we sceptics want, a moderate voice, issues acknowledged that need addressing, etc
so very current and now.

I thought it was out today and thanked Richard for going public, with all that sceptics just want to be aired.... And I gave Andrew Montford a call

The irony is, it was written in January 2010....

And tomorrow, Al Gore is going to 'Reveal the Deniers' I guess he means me?
What he wants done to the deniers or what happens next is anybodies guess..

With all the scientist I've discussed issues with (where they have dropped pre-conceptions about sceptics) we find we are virtually in agreement about the science..

The only thing probably we might argue/discuss is what to do about percieved risks of future projection.. IE POLICY not science.... energy policy, economics, etc,etc

I think I'm on your side, you are on mine..

The problem I have is with greenpeace/politicians and a few scientists that are alarmist and grab the media and political attention.. and label others..

So much so that when climate scientists do chat with 'sceptics' (on the serious blogs) they are surpised to find (hopefully)intelligent, informed, rational people many with decades of professional experience in other disciplines, including engineering, science, economics,statiticians, etc, that they can discuss issues with.

I've tried to engage with 'climate scientists' and some sceptics might think as believers (ie Mark Lynas, Leo Hickman) because I think they are sincere and honest. But this was based on my own personal experience as having a friend that is an active climate scientist (edited IPCC Summary for policy makers, and key member of a UK gov advisory team to this day) and my sister in law, who is a Green party Press Officer, former editor of Greenworld, and a former Green Parlimentary Candidate.

I know they are both very nice people.

Yet tomorrow, the politics of it all.. has Al Gore - Revealing the Deniers

When we are revealed (make no mistake he means rhetorical me, ie Watts Up Guess Author, Bishop Hill contribution, my own 'denier blog' RealClimategate)

Just what is exactly is Al Gore going to do..... Ask me over for tea ? ;-)

I really do not like the political climate.

One thought, as a climate scientist commenting here, you may have some people 'blaming you for all ills' don't take it personally (some venting), this shoud soon turn into gratitude for actually engaging and discussing issues. The very same happened to Judith Curry, lots of suspicion, when she started engaging with sceptical blogs a few years ago now. Now she is seen by the less moderate climate scientists as something of a heretic!?

One final thought, which should make it all worthwhile ;-) for Tamsin.
If you're really lucky Josh might draw you your very own cartoon...

Apparently, Judith Curry likes the one of her as the Laser Toting Space babe, defending Montford and The Hockey Stick Illusion..

Sep 13, 2011 at 2:32 PM | Unregistered CommenterBarry Woods


I commend your efforts to make your science more open and transparent. It is a worthy effort on your part.

The comments on sustainabilty I having difficulty with, .............. because ..............I have to say.............. it is recognised as being a well worn tactic by activists to side-line or deflect controversy over climate change by engaging critics by listing things that everyone can agree about.

Sorry, I know it is unworthy of me, but that listing still raises a doubt in my mind about what primarily has drawn you to your current vocation.

Sep 13, 2011 at 2:50 PM | Unregistered CommenterMac


Thanks for your thoughtful reply.

"many climate scientists ... have this cliche of 'sceptics' of some republican, ignorant of science,oil swilling creationist evil exxon funded capitalist in their minds"

Absolutely they do, and non-scientists too. I fight against people who are anti-American, anti-republican or anti-creationist, because, as the cliche goes, "some of my best friends are.." from my time living in America during my PhD. (Just as one of your friends is a climate scientist... ;))

It's not just this. Many climate scientists are out of touch with the level of complexity and understanding of the debate at places like BH. I forget myself, sometimes, even though I am increasingly in touch with it. I come out with pat lines that are several years out of date: sledgehammers to deal with the big errors of "The Great Global Warming Swindle", rather than tweezers to unpick the multiple, much more detailed and informed lines of concern that people have nowadays.

I'm definitely viewed within the University of Bristol as a scientist that engages significantly with the public and sceptic communities (more in person than online, so far). But a commonly-made mistake by scientists that don't is to lump all sceptics together in one group. I think many scientists got tired early on of arguing that CO2 is definitely a greenhouse gas and that warming definitely has occurred, and didn't realise that many sceptics do agree with the essential tenets of AGW but doubt the certainty of, say, the magnitude+timing or the best political actions (if any).

We are definitely culpable on this, and I do my best amongst my peers to spread the message of "They're better than you think!" :)

On the other side, if I may make a criticism myself here, some sceptics muddy the waters by challenging scientists on policy issues or governmental / NGO viewpoints, dragging the discussion away from the pure science. If we scientists answer these, we are (rightly) described as advocates. I no longer answer questions outside the science. For my views on energy efficiency / nuclear / geoengineering / solving poverty, you'll have to find me in the pub :)

Hope that helps. I'm worried I've blown it before I've even started here at BH! Here's hoping for that cartoon….

Sep 13, 2011 at 2:57 PM | Unregistered CommenterTamsin Edwards


In my defence, the question in the interview was "Give 3 words that describe how you got there" not "..that describe who you *are*".

So I'll try to describe the "greenie" bit - i.e. how I was drawn to the "environmental" aspect of this job (as opposed to any other physics job). I'm at risk of over-sharing here, but my instinct is to be honest and open in the hope that I gain your trust and/or respect.

Aged 7ish: hearing a talk at school on the ozone layer - probably my first awareness of an environmental issue

Aged 14ish: talking to family and friends about wanting to do something useful for the environment - my concerns were habitat loss, species extinction, pollution, landfill, finite resources

Post-PhD: talking to a friend (@ed_hawkins in fact) about leaving particle physics and what to do next - I wanted to do something more broad and more directly "useful to society" (particle physics is definitely useful but the benefits are abstracted from day-to-day research). He said he enjoyed climate modelling and sent me details of the jobs email list.

I also looked into other "physics/maths/computing + useful to society" topics, e.g. spatial modelling of social problems and vulnerability.

I don't think you could argue that viewing climate modelling as "useful to society" indicates a pre-disposed view to "spend lots of money mitigating AGW" - the causes and likely futures of climate change are globally-relevant questions that need answers. I don't go searching for confirmation of alarmist viewpoints. In fact, my first post-doc was entirely modelling palaeoclimates, not future climates, and we haven't yet used those results to try and calibrate model predictions of the future (Google project PalaeoQUMP if you want to see a bit more on this).

I really am not an activist. For example, I avoided going to the Brisbane march about climate change action while I was there precisely because I am a climate scientist and want to be seen as impartial. Ditto climate camp etc. I don't even talk to my family and friends that much about what I think we should do: only the science of what has happened, what might happen, and the range of options (such as geoengineering).

It's only in the past 6 months to (less than?) a year that I've become super-aware of drawing the line between my science and my opinions. I used to answer policy questions with "This is just my opinion, but...". And now I just don't say. So if I was an activist, I wouldn't be a very good one :)

Sep 13, 2011 at 3:21 PM | Unregistered CommenterTamsin Edwards


I saw your presentation against the Great Global Warming Swindle. Many of your rebuttal points presented in there are simplistic, and some outright wrongly directed.

Sep 13, 2011 at 4:28 PM | Unregistered CommenterShub

Hi Shrub,

It would be helpful if you could let me know which points?


Sep 13, 2011 at 4:35 PM | Unregistered CommenterTamsin Edwards

Dear all,

Apologies for making this thread all about me. I'm a newbie here at BH as you know, so I've only just noticed all the discussion about me on pages 1-3. (Richard sent me a link to page 4 and I hastily replied before checking back).

But I'd like to reply to some of the earlier comments.

Green Sands - glad you found the SUPRAnet link interesting, thanks. They are a good group of proxy scientists, statisticians and palaeoclimate modellers trying to do a better job of quantifying uncertainty in reconstructions. It's not an easy task. But as far as I can see many key players in proxy reconstructions are working more closely with statisticians who are interested in this research area.

PaulM - thanks for the welcome and for sticking up for me. I saw Richard was appreciated here so I thought I'd join in too. Got my fingers burnt! Think my copy of HSI is waiting at home for me today.

Richard - thanks for sticking up for me!

BBD - thanks for sticking up for me, and yes, the skin is noticeably thicker now than it was yesterday! Aargh. But I am greatly encouraged now that I've read everyone's welcoming comments on pages 2 and 3.

Shub - apologies for misspelling your name.

Philip - thanks for the welcome. I do intend to stick around. <joke>Unless you all make me cry</joke>

Bish - thanks for stepping in! This is the lion's den. Perhaps you are Aslan?

David Porter - "Bishop, you've been taken over. You've been infiltrated. Your blog is now a talking shop for the alarmist." - was this tongue-in-cheek? You really don't want to talk to climate modellers? [And by the way, I'm not an alarmist - I try to quantify the uncertainties :) ]

Mac - I've just seen your original comments, before the one at the top of p4. As I said in an earlier post, the 3 words were to describe how I became a climate modeller. And I would describe "greenie" as meaning trying to reduce use of resources etc, as Barry agreed recently. So many topics are tagged with the "green" label - washing my cat food tins for the recycling doesn't mean I am a rabid activist :)

And is Brian Cox being my supervisor a problem? I never discussed climate science with him during my PhD, and I had no contact with him from when I submitted my final PhD thesis (2006) until May this year. So I'm not influenced in my climate modelling by him, if that was what you were hinting at? I'm only influenced in the sense that he is an excellent physicist and a big-picture thinker, so I try to be these.

On your (Mac's) specific comments:

"Will climate modellers 'correct' the models (and not just reset them) so that modelled outcomes match observations?"
My work is exactly the opposite - varying lots of poorly-known parameters in the model to test which best simulates the observations. Not tuning those parameters so that the model does fit the observations.

"Can a climate modeller who is also a 'greenie' correct the models that in all probability runs counter to that person's beliefs"
Already addressed the "greenie" and the "correct". I test the models, I don't change them.

"on an ideological mission"
Nope! Hope I've reassured you somewhat on this point.

"No data, no observation will shake their faith in the consensus, the models have become sacrosanct."
Quite the opposite - see above.

"I agree the alarmists come to preach, deflect, conflate and decry. To them we are still all "deniers".
Hope I'm starting to convince you that I'm not doing any of these, and that I'm no longer using the "d word.


Sep 13, 2011 at 5:32 PM | Unregistered CommenterTamsin Edwards

Re Tamsin

Welcome to the madhouse and if it's any consolation, Dr Curry also got a bit of a rough ride. From my pov, it's great to have people willing to comment 'from the trenches' here and add to the debate. Bit disappointed to see your SUPRAnet isn't the same as the Gartner/Snowcrash version though :)

Sep 13, 2011 at 5:54 PM | Unregistered CommenterAtomic Hairdryer

Hi Tamsin,

You say:

"My work is exactly the opposite - varying lots of poorly-known parameters in the model to test which best simulates the observations. Not tuning those parameters so that the model does fit the observations."

This raises several thoughts with me. Firstly, testing which parameters best simulates the observations is simply the prior step to choosing (aka "tuning") the parameters so that the model does fit observations.

Secondly, in testing do you run these on a forward prediction basis ie set aside say the last ten years of observations, select parameters that give good fits over the preceding data time span and then run the model to test the forward prediction?

I ask the second point because I am very familiar with what happens in fitting complex models with many parameters. Very often the parameters are fitted to be able to say "look how good the model is over the data period". This can result in an apparently good fit to observations, but a poor predicitve capability at unmeasured locations (ie future times in the case of a GCM). Its like saying you have reduced uncertainty and improved the fit to observations in a regression by using a fourth order polynomial not just a straight line. The fourth order polynomial might appear to be a good fit (lots of free parameters!) but it may be a terrible predictor of values at unmeasured locations or times.

Finally, can you give me some idea of the dimensionality of the model you are trying to fit. By this I don't mean its real world coordinate system but the number of parameters on which you run sensitivities?

Sep 13, 2011 at 6:20 PM | Unregistered CommenterThinkingScientist

I'd like to second what Barry says. Briefly
(a) It is quite possible to be a sceptic and 'green'. I am a member of 3 environmental-type organisations.
(b) It's only through skeptics and AGW-believers talking to each other that each side can realise that in fact the other side are not the evil ogres they are often portrayed as, so more participation from Tamsin and Richard is a Good Thing.

Thanks to Tamsin for substantially clarifying her position.

Sep 13, 2011 at 6:28 PM | Unregistered CommenterPaulM



I thought you might be interested in a snapshot of the sceptic demographic here. The Bishop ran a snapshot survey a while ago

Also there are some more detailed summary bio's at Judith Curry's blog here, for a typical selection of sceptics.

In general, we seem to lean towards a traditional science background, and be of middle to mature age.

That seems to fit my case, a retired geologist.

Sep 13, 2011 at 10:20 PM | Unregistered CommenterPharos


I'm a long-time visitor here, over 2 years I think and only, maybe, 2 comments! One of the reasons is, as a layperson (bitten with the bug of an obsessive interest in the "climate blogosphere"), I have benefitted greatly from the open discussions - I have never felt BH to be an echo-chamber.

I was very pleased to see Richard Betts begin to participate (also from time to time Richard Tol and others I can't name offhand) but didn't want to take up space to say so - if you see this, Richard, I do appreciate it greatly.

Now that you have begun to participate, Tamsin, I felt it could be appropriate to give my small input to encourage you, Richard, and others, to keep checking back and participating. I'm sure there are many other shy lurkers who would feel the same.

I have to say - it gives me hope! Thank you.


P.S. I just wish tomorrow wasn't a continuation of the "climate wars" with the same old, same old from the self-appointed expert/guru - what's the slogan, expose the deniars or something? I don't know what I qualify as - as a lowly anthropologist (non-practicing, for many reasons), I certainly don't feel qualified to call myself a sceptic as that implies I have a total understanding of all the related issues (not to mention the all-important degrees and publications). But I have acquired very good knowledge of the basic issues and so do not feel that the term deniar applies to me either! Well, I know who is being referred to - others in powerful (political) positions - but by the same token, interested, informed, non-shill, lay people like me, who have discovered what is going on, are a huge force to be reckoned with and this kind of event is counter-productive, at minimum.

Sep 13, 2011 at 10:34 PM | Unregistered CommenterKendra

Hi Tasmin

Working through SUPRAnet links presently immersed in "lakes, oceans and ice cores"!

A quick very basic question if you have a moment re global temperature data sets, which do you rely on for your research?

Is it terrestrial or satellite based? I have aquired the perception that most "in the trade" gravitate to HadCRUT3/v?

Sep 13, 2011 at 11:00 PM | Unregistered CommenterGreen Sand



I agree that "expose the deniers" is likely to achieve nothing more than furthering the polarisation of opinion.

Sep 13, 2011 at 11:55 PM | Unregistered CommenterRichard Betts

Orson "OK, Then tell us where the feared energy is coming from, if not from cloud amplification?"

BBD "It comes from water vapour amplification (positive feedback). There is a great deal more water vapour in the atmosphere than cloud. Are you missing the point here? (BTW, that was Judith Curry in the quote, not me)."

YES, yes, the theory we know. Now where should this evidence appear? Where should we look that we are not now looking?

"(BTW, that was Judith Curry in the quote, not me)." Huh? (I don't recall quoting you in this thread, or Curry.)

Sep 14, 2011 at 12:01 AM | Unregistered CommenterOrson

Tamsin and Richard, if I may, I think you may be placing too much hope in climate models. I suspect we shall need a series of huge breakthroughs in physics, in mathematics and in computing before they will be of much use for practical guidance involving prediction. But who knows when such breakthroughs will occur? Given that uncertainty, and the likelihood that computers will be crucial one day, it is a good thing that some people like yourselves devote time to making the best you can of them. In the meantime, I think entrepreneurs (for economic growth), civil engineers (for better structrures), and agricultural scientists (for making the most of the soil etc) will have more immediate and useful contributions to make to help us cope with climate variations. It is most unfortunate that the GCMs have been misused for political purposes over the last 30 years or so, bringing harm and loss of various kinds to societies around the world. Not your fault of course - yours is a noble approach, but it must pain you to see what has happened to date.

Sep 14, 2011 at 9:54 AM | Unregistered CommenterJohn Shade


Explain this;

Here was an opportunity for a climate scientist to persuade, to discourage or perhaps to denounce the use of "d" word and argue that everyone should be open about the climate debate and to refrain from censorship. Why wasn't that opportunity taken?

The NRDC (Natural Resources Defense Council) is an international environmental advocacy group.

Sep 14, 2011 at 12:05 PM | Unregistered CommenterMac

"Where should we look that we are not now looking?"

In the circular argument;

CO2 x f = current warming (where f is the number required to balance the equation).

This equation would never have seen the light of day had we been experiencing declining temperatures. Would we have seen a headline "Fossil fuel slows our decent into ice age", I somehow doubt it.

Sep 14, 2011 at 1:49 PM | Unregistered Commentersimpleseekeraftertruth


YES, yes, the theory we know. Now where should this evidence appear? Where should we look that we are not now looking?

I'm not sure I understand what you are driving at.

To cover all the bases:

- Temperature. Increase in second half of C20 is larger than in first half. A proof that the rate of warming over the whole century is increasing:

To make the trend lines more visible (and for no other reason) I have used the annual means for HADCRUT3 and GISTEMP. The actual trends were calculated from the monthly anomalies.

HADCRUT3 and GISTEMP. Trends: 1900 - present; 1950 - present.

Evans & Puckrin (2006) examines actual measurements of DLW and compares them with modelled estimates. Emphasis added:

Measurements of the downward radiative flux have been made for several important greenhouse gases. At mid-latitudes in summer as compared to winter, our measurements show that the downward surface flux from H2O has doubled to 200 W/m2. The water increase causes a reduction of the fluxes from the other greenhouse gases. These measurements show that the greenhouse effect from trace gases in the atmosphere is real and adds significantly to the radiative burden of the atmosphere. The greenhouse radiation has increased by approximately 3.52 W/m2 since pre-industrial
times. This compares favorably with a modeled prediction of 2.55 W/m2. Measurements such as these can provide a means by which to verify the predictions made by global warming models (Puckrin et al; 2004).

Brown et al. (2007) uses satellite observations to demonstrate the upward trend in atmospheric water vapour over the major ocean basins (emphasis added):

The Topex Microwave Radiometer was decommissioned in January 2006, but left 13 years of continuous observations. An end-of-mission recalibration effort was recently completed, yielding a high quality TMR climate record of precipitable water vapor and cloud liquid water. This dataset is analysed to observe the trends from 1992-2005. It is found that the global precipitable water vapor trend is positive at 0.9 + 0.06 mm/decade. Maps of regional water vapor trends are generated and it is shown that the correlation between sea surface temperature trends and water vapor trends follows a simple relationship derived from the Clausius-Clapeyron equation.

Sep 14, 2011 at 7:05 PM | Unregistered CommenterBBD

Hi all,

Thanks for your replies, questions and encouragement. I've been meaning to reply to you all day but work and chores had to be done first and now I'm exhausted!

ThinkingScientist - great questions - you have inspired me to start (finally!) a blog where I can post longer answers to questions like yours. Watch this space...

Everyone else - I'll be back, hopefully tomorrow.


Sep 14, 2011 at 10:16 PM | Unregistered CommenterTamsin Edwards

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