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Myles out of line

The reverberations from the Lewis/Crok report are still playing out in the blogosphere. In particular there are some interesting comments at Ed Hawkins' blog.

One of the memes that is being pushed by our climatological friends is the idea that the Lewis/Crok range for transient climate response (i.e. short-term warming) is similar to that of the IPCC models. Myles Allen was the first to promote this idea, in his comments at the Science Media Centre.

Their 5-95% range of uncertainty in TCR (kindly provided by Nic Lewis) is 0.9-2.5 degrees C, almost exactly in line with the range of the models shown in their figure (1.1-2.6 degrees C).

This idea has now been repeated by Ed Hawkins:

Focussing on TCR, Lewis & Crok give a ‘likely’ range of 1.0-2.0K. The same IPCC AR5 range is 1.0-2.5K, taking into account other lines of evidence. The 5-95% ranges from Lewis & Crok are almost the same as the 5-95% ranges from the GCMs (Nic Lewis confirmed this to Myles Allen).

Well up to a point, Lord Copper. As Troy Masters - another independent scientist with publications in the area - has pointed out in the comments at Ed Hawkins' blog, a 5-95% range, being so wide, can hide a multitude of sins, including for example vastly different skews from one distribution to another.

...these ranges can be similar while at the same time the specifics of the actual distributions (median, mode, etc.) can be very different and have largely different policy/impact implications. You are right that the similarity in these ranges between Lewis and Crok and the IPCC report might make the distinction insignificant (although estimated impacts/costs are disproportionately affected by the upper bound) IF the IPCC did not imply knowledge of the distribution within that range of TCRs. However, while the report does not explicitly give a “most likely” value for TCR, it implicitly suggests one with the statement in the SPM that global surface temperatures are “more likely than not to exceed 2C [above pre-industial by 2100] for RCP4.5 (high confidence)”. This is based on the GCMs with an average TCR of 1.8 K, significantly higher than the estimated “most likely” value used in Lewis and Crok. Similarly, I think most people would agree that if TCR is 1.0 K and ECS is 1.5 K (both within the “likely” range of the reports), we are unlikely to hit that 2K target under RCP 6.0 by 2100, but again AR5 says “warming is likely to exceed 2C for RCP6.0…(high confidence)”, thereby implicitly assigning a low probability to the lower end of that range.

I don’t think the IPCC report can have it both ways. Either the SPM must say “we don’t know” about whether we are likely to exceed 2K under RCP4.5 and RCP6.0, because the likely range of TCRs include those that exceed or fall below this mark, or it must stop saying that estimates of TCR are consistent simply because the ranges are consistent (as those statements rely on more specific aspects of the distribution). Given that RCP4.5 includes increasing emissions up to 2040, and RCP6.0 increasing emissions up to 2060 (albeit neither at the rate of RCP8.5), consider the difference of the implications when using the IPCC implicitly assumed distribution of TCR estimates vs. the explicit most likely values of Lewis and Crok:

IPCC AR5 using implictly assumed TCR distribution: we are more likely than not to exceed 2K by 2100 under the scenario where emissions continue to increase up to 2040, and likely to exceed 2K under the scenario where emissions continue to increase up to 2060 (high confidence).

Lewis and Crok: we are unlikely to exceed 2K by 2100 under the scenario where emissions continue to increase up to 2040, and more likely than not to stay below 2K by 2100 under the scenario where emissions continue to increase up to 2060.

In both cases we might say the TCR ranges are the same, but they convey largely different messages to policy makers.

In fact it's worse than that, because although the IPCC's CMIP5 models have an average TCR of the order of 1.8°C, as Lewis and Crok point out in their report the amount of warming that the models predict is even higher than this number implies.

It is actually possible to show the very significant discrepancy between what the IPCC is telling policymakers and Nic Lewis's work, based on the AR5 forcing and heat uptake data and the observational studies. In Figure 12.8 of the Fifth Assessment, the IPCC reports the range of projected warming under the various RCP scenarios, including the 5-95% and 17-83% ranges as well as the medians. Nic Lewis has kindly sent me the equivalent projected figures, calculated using a two-box model and using the various key percentiles from the TCR and ECS ranges in his report. I have drawn these (in blue) next to the IPCC's figures (in red - main warming projections 17-83% ranges and means, based on the ensemble of CMIP5 models; in yellow - 5-95% and 17-83% ranges and medians from AR5 Figure 12.8, based on Rogelj et al 2012).*


The difference, as I'm sure you will agree, is pretty stark. But Lewis's results are, in climatological speak, "almost the same" as the IPCC's.

One last thing. I wondered how it was that Nic Lewis could have provided Myles Allen with the extra data about the range of his TCR estimate without the details of the skewness getting passed on too. Did he not pass on the likely range too?

I asked Nic about this. It turns out he provided Myles with the 'likely' range first, and Myles then asked for the 5-95% range. Nic was worried that quoting just the 5-95% range would mislead people. So he sent Myles the 5-95% range, stating that he was happy for Myles to quote it as long as he also gave his (Nic's) median and likely range.

Oh dear.

 *Nic asks me to note the following caveats: The best estimates and likely ranges are not identical to those given in the Lewis and Crok report (although the TCR best estimate is virtually the same): the values given in the report have been made more conservative. The percentiles that these projections represent will only approximate the percentiles of the TCR and ECS values used, because some uncertainty is not common to TCR and ECS.

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Reader Comments (71)

Wolf, Wolf!

Mar 12, 2014 at 1:25 PM | Unregistered Commenterkim

Can others see the chart? The chart is not visible for me.

Mar 12, 2014 at 2:02 PM | Unregistered Commenterbernie1815

Nice chart.

So, in all three comparisons we can see that:

(a) The upper limit of Lewis' 17-83% range lies below the lower limit of the 17-83% range from the IPCC
(b) Lewis' median value lies below the 5-95% range from the IPCC
(c) The IPCC median values lies above Lewis' 17-83% range (and in the RCP4.5 case, the IPCC median lies above Lewis' 5-95% range.

There is no way to construe these figures as "comparable", "similar", "consistent with" or any other way of describing a possible likeness. Lewis' figures are all significantly lower than the IPCC numbers.

Is Myles Allen blind, stupid or worse?

Mar 12, 2014 at 2:57 PM | Registered Commenterthinkingscientist

Well Myles must be right. Certainty in the range 5% - 95% is, to all intents and purposes, almost the same as 0% - 100%. I will go along with that, we are certain somewhere between 5% (how can you be 5% certain of anything?) and 95% (which means near absolute certainty). Great, I am much more certain, or uncertain, than I was when I read Myles.

5% to 95% certain is exactly the same as 5% - 95% uncertain. That makes all clear.

I think the word 'certain' is the problem, Perhaps 'havent got a clue' would be more to the point. I am 100% certain, when I look at the plots of actual temperature rise in the past 17 years compaired with the models that the latter are wrong and useless, except to dupe MPs.

Mar 12, 2014 at 3:03 PM | Unregistered CommenterWilliam Baird

I think we should give the key Myles Allen phrase a runaround in some other fields:

In poetry, William McGonagall was almost the same as Robbie Burns
In ski jumping, Eddie "the Eagle" was almost the same as Matti Nykänen
In biology, Trofim Lysenko was almost the same as Gregor Mendel

I'm sure such examples will help the layman see the great wisdom of the settled science of climate.

Mar 12, 2014 at 3:14 PM | Registered CommenterRichard Drake

I went to the first Glasgow Uni gravitational waves presentation in 1974. My tutor called the project leader a moron because he didn't understand basic physics. Forty years later. Zero gravitational waves.

James Lovelock in the Guardian

The great climate science centres around the world are more than well aware how weak their science is. If you talk to them privately they're scared stiff of the fact that they don't really know what the clouds and the aerosols are doing. They could be absolutely running the show. We haven't got the physics worked out yet.

Translation. It's bollocks.

Mar 12, 2014 at 3:32 PM | Unregistered Commenteresmiff

This SMC took a line and pushed it very hard (using Allen, Hawkins and Betts) on March 6th when Lewis' GWPF was published. This line appeared repeatedly on social media. It was: "Sceptical bloke confirms global warming!" The implication being "we were right along". But this isn't newsworthy. Any competent editor looks for something unusual: the man bites dog angle. That is fulfilled by reading the report itself: the IPCC has over-estimated warming.

I think only the BBC took the bait offered by SMC.

For this reporter and editor, watching the Science Media Centre is like watching a very amateurish version of The Thick Of It.

Mar 12, 2014 at 4:09 PM | Unregistered CommenterAndrew

Ben had a very good summary of the SMC's spin here, not new to most of you I suspect:

The spin is only persuasive if one already shares the cartoon version of what a "climate sceptic" is. Hasn't the internet made this impossible?

Mar 12, 2014 at 4:14 PM | Unregistered CommenterAndrew

Mar 12, 2014 at 4:09 PM | Andrew

This SMC took a line and pushed it very hard (using Allen, Hawkins and Betts)

In what way do you think the SMC "used" me?

Mar 12, 2014 at 5:16 PM | Registered CommenterRichard Betts

For this reporter and editor, watching the Science Media Centre is like watching a very amateurish version of The Thick Of It.

This is a PR organisation that not only has the Glass Man in its lobby but featured it in its promotional video.

Mar 12, 2014 at 5:35 PM | Unregistered Commenteranonym

Hi Richard Betts,

Just for the record, do you agree my technical summary points (a) - (c) in my post above are accurate statements?



Mar 12, 2014 at 5:56 PM | Registered Commenterthinkingscientist

I think Richard will have the grace to concede that. Lets hope he does not feel obligated to qualify away the essence of it.

Mar 12, 2014 at 7:28 PM | Registered CommenterPharos

Pharos - yes, but watch. He won't directly respond to me. He never does. Always avoids my questions.

Mar 12, 2014 at 9:25 PM | Unregistered CommenterThinkingScientist

Keep going down guys. ECS looks pretty close to 0.7 C/doubling, ie Lindzen's CERES median value for TCS.

You have to take into account both the ~60 year cycle and the overall solar effect, which the IPCC ensemble models omit. Once you do, it drops your derived ECS falls well under 1 C/doubling.

Also helps to use a validation dataset with limited recent UHIE contamination, which HadCET is and HadCRUT isn't.

Mar 12, 2014 at 9:27 PM | Unregistered CommenterBruce of Newcastle

If you are fed up with my usual moan, skip to the next comment. Otherwise, ECS is a concept of doubtful validity. I ask time and again for the source of it as a defensible concept. No answer. It would be nice to know why so many people accept it apparently without question. I may well be a fairly ignorant Oxfordshire housewife way out of my comfort zone, but the fact that one can play statistical games with the observations and models does not in fact prove that the results have any meaning in the real world. I see the Lewis and Crok work as establishing limits to CS IF it were a real thing. I don't see how it can be shown to be real by assuming it exists, never mind ascribing a value.

If the water in my kettle boils after five minutes from cold, how how will it be after seven minutes?

Mar 12, 2014 at 9:49 PM | Unregistered Commenterrhoda

Yes, rhoda. As I have said before, ECS seems to be the one bit of "climate science" that even sceptics regards as valid.

But there are one or two commenters who have suggested that there is no more reason to believe it makes sense than anything else in the climate science crock.

Mar 12, 2014 at 10:00 PM | Registered CommenterMartin A

I note that I commented on a Myles Allen post without insulting or defaming him by name.

I'll try to do better in future.

Mar 12, 2014 at 10:12 PM | Unregistered Commenterrhoda

I recall that when I first got involved as an AGW sceptic I read a lot written by Fred Singer, the arch-sceptic, and he always always stated that (a) CO2 is a greenhouse gas and (b) the warming for a doubling of CO2 concentration would be about 0.6 degC at the end of the 21st century and therefore almost entirely benign/beneficial.

Singer has a remarkable record as an atmospheric physicist. He is an "old school" scientist. He studied under Van Allen. A remarkable scientific career, unlike some of the shallow climate scientists of today.

I still think he is going to be proved right.

Mar 12, 2014 at 10:25 PM | Registered Commenterthinkingscientist

Double post deleted.

Mar 12, 2014 at 10:34 PM | Registered Commenterthinkingscientist

Thanks for that thinkingscientist - I've been thinking a lot about Singer as I've pondered the origins of scepticism once again, prompted by what seemed to me some slightly less than grounded thoughts of another. I don't know enough about him. Any web refs that do justice to the history in his neck of the woods would be appreciated.

Mar 12, 2014 at 11:34 PM | Registered CommenterRichard Drake

Mar 12, 2014 at 10:00 PM | Martin A

Totally agree with Martin and Rhoda and I'm an ex 'climate scientist'. It is such a small field too. While I was at Reading just quoting recent names we also had Brian Hoskins, Julia Slingo, Piers Forster, Mat Collins, Richard Betts (though I don't remember him) and luckily I think I left just before Ed Hawkins got to annihilate me at squash. On top of that I remember Myles being around frequently too being just next door. They are all very nice and very intelligent people, I just also think they are very, very wrong with the shared theory they seem to hold.

Mar 12, 2014 at 11:38 PM | Unregistered CommenterRob Burton

rhoda - re: your kettle - I think you have the times the wrong way around.

Taking the kettle analogy, as I understand it, the idea is that you start with your kettle of water in thermal equilibrium with its surroundings. Then you fancy a cuppa, so you apply some Watts/m^2 to its base. As a result it starts to warm up. As it gets warmer it will naturally radiate heat to its surroundings.

For the sake of simplicity, lets assume you are running a tight ship and only put it on a very low gas which is insufficient to induce boiling. At some point it will have warmed up to a temperature where it will radiate the same amount of power as the Watts/m^2 you are applying, hence regaining thermal equilibrium. At this point it will warm no more and the temperature rise will be its "Equilibrium Sensitivity" to the Watts/m^2 you supplied. The "Transient Response" will be the temperature rise it achieves at some defined point in time along its path to the new equilibrium temperature. The definition of that intermediate point in time can be chosen to investigate some period of interest - perhaps it could be the length of an advert break or the time to read a blog post.

I might have got that wrong and I might have missed your point. Apologies if so - I haven't had time to read the report yet. Have you? I suggest it will be worth it, I've followed some of Nic's other work and posts and he is a very sharp and thorough chap. FWIW my impression is that is one reason why the wagons are being circled by the likes of Allen and Hawkins - they know Nic can (and will) take poor quality work apart.

Mar 12, 2014 at 11:55 PM | Unregistered Commenternot banned yet

Judith Curry's Foreword to the Report:
The sensitivity of our climate to increasing concentrations of carbon dioxide is
at the heart of the scientific debate on anthropogenic climate change, and also
the public debate on the appropriate policy response to increasing carbon
dioxide in the atmosphere. Climate sensitivity and estimates of its uncertainty
are key inputs into the economic models that drive cost-benefit analyses and
estimates of the social cost of carbon.
The complexity and nuances of the issue of climate sensitivity to increasing
carbon dioxide are not easily discerned from reading the Summary for Policy
Makers of the Assessment Reports undertaken by the Intergovernmental
Panel on Climate Change (IPCC). Further, the more detailed discussion of climate
sensitivity in the text of the full Working Group I Reports lacks context
or an explanation that is easily understood by anyone not actively reading the
published literature.
This report by Nic Lewis andMarcel Crok addresses this gap between the IPCC
assessments and the primary scientific literature by providing an overview of
the different methods for estimating climate sensitivity and a historical perspective
on IPCC’s assessments of climate sensitivity. The report also provides
an independent assessment of the different methods for estimating climate
sensitivity and a critique of the IPCC AR4 and AR5 assessments of climate sensitivity.
This report emphasizes the point that evidence for low climate sensitivity
is piling up. I find this report to be a useful contribution to scientific
debate on this topic, as well as an important contribution to the public dialogue
and debate on the subject of climate change policy.
I agreed to review this report and write this Foreword since I hold both authors
of this report in high regard. I have followed with interest Nic Lewis’
emergence as an independent climate scientist and his success in publishing
papers inmajor peer reviewed journals on the topic of climate sensitivity, and
I have endeavored to support and publicize his research. I have interacted
with Marcel Crok over the years and appreciate his insightful analyses, most
recently as a participant in
The collaboration of these two authors in writing this report has resulted in a
technically sound, well-organized and readily comprehensible report on the
scientific issues surrounding climate sensitivity and the deliberations of the
IPCC on this topic.
While writing this Foreword, I considered the very few options available for
publishing a report such as this paper by Lewis and Crok. I am appreciative
of the GWPF for publishing and publicizing this report. Public accountability
of governmental and intergovernmental climate science and policy analysis is
enhanced by independent assessments of their conclusions and arguments.
Judith Curry
Atlanta, GA, USA
February 2014
Judith Curry is Professor and Chair of the School of Earth and Atmospheric Sciences
at the Georgia Institute of Technology. She is a fellowof the AmericanMeteorological
Society, the American Association for the Advancement of Science, and
the American Geophysical Union.

Mar 13, 2014 at 12:01 AM | Unregistered Commenternot banned yet


Your points are a correct reading of the comparisons between the blue and yellow boxes in the Bishop's figure.

However there's a few points to note:

1. The projections presented in the SPM (so highlighted to policymakers) are those in the red boxes, i.e.: the direct CMIP5 model output - see Figure SPM.7 and Table SPM.2 here. These overlap a bit with the blue boxes.

The results in the yellow boxes (with higher levels of warming) are not shown in the SPM. I guess the WG1 authors didn't want to rely on a single study for SPM conclusions - we all remember what happened as a result of that in the TAR…..! [*cough* hockey stick *cough*] :-)

2. The Bish has made a mistake in saying that the red boxes are 17-83% - actually they are 5-95% (see caption for Table SPM.2) and are described as the "likely range".

3. I think the Bish has also made another (small) mistake in the baselines. As far as I can tell from comparing against the numbers in Table 3 of the Lewis & Crok report, he's plotted the numbers which were given for the 2012 baseline (e.g.: the median of 2.1 for RCP8.5). However, the IPCC figure uses a baseline of 1986-2005. From L&C and AR5 respectively, 2012 is taken as 0.8C warmer than 1850-1900, and 1986-2005 is taken as 0.61C warmer than 1850-1900, so this mismatch of baselines increases the difference between L&C and IPCC by 0.19C.

4. It's not usually valid to compare medians against means in a skewed distribution, as they show different things. L&C give the median, but the red boxes (CMIP5) give the mean. If the distribution of CMIP5 is the same as those from L&C and Rogelj et al, we'd expect the median to be lower than the mean. (Unfortunately the CMIP5 medians do not seem to be given in Chapter 10).

So while the projected warming for 2081-2100 from L&C is indeed lower than that from IPCC, the differences are not so large as suggested by the Bish's figure, especially when (i) comparing 5-95% ranges of L&C and IPCC "official" (red) projections, (ii) taking into account the mistake in the baselines and (iii) bearing in mind the comparison of means and medians.

Mar 13, 2014 at 12:13 AM | Registered CommenterRichard Betts

thinkingscientist @ 2:57pm - I agree with your reading.

Richard Betts - please answer ts's query @ 5:56pm.

Mar 13, 2014 at 12:15 AM | Unregistered Commenternot banned yet

Richard Betts - apologies for the crossed post.

Mar 13, 2014 at 12:17 AM | Unregistered Commenternot banned yet

Richard Betts - thank you for the additional information. I hope the Bish responds.

Re: your point 4, please can you expand on what you think the mean does show in a skewed distribution and the value of comparing it between distributions?

Mar 13, 2014 at 12:25 AM | Unregistered Commenternot banned yet

There's an easy answer to all this. After extensive and robust modeling experiments, climate scientists will announce (by press handout) that the tipping point for CAGW has been accurately determined to be 1.4 deg C rather than 2.0 deg C by 2100.

In line with projections of the IPCC, Lewis/Crok and anyone else for that matter.

Mar 13, 2014 at 3:01 AM | Registered CommenterGrantB

The Allen-spin, for spin it is, is not very becoming for anyone with scientific aspirations. It might look good as a political/media ploy to try to take the sting out of an unscripted event unmanaged by his side - the publication of a report which criticises IPCC methods and shows how less scary results than theirs can readily be obtained by improving upon said methods. Richard Betts has rallied to the flag raised by Allen on this new skirmish for hearts and minds in the media, but his warcries are but squeeks.

Mar 13, 2014 at 7:00 AM | Registered CommenterJohn Shade

I noted that my comments were removed on Ed Hawkins blog in response to Clive Best's comment about CO2 effects being well understood (a whole load of theoretical equations and talk about changes to radiation)

God forbid I broke the AGW rule of stating that you need to do experiments. Ed's blog looks very much like a theorists get together completely devoid of reality but more importantly of actual scientific method.

A common excuse is that we can't do experiments on climate. Doesn't stop people quoting MODTRAN and line by line calculations which are a specific characteristic of gases and which can be measured and characterised in a lab.

AGW has too many excuses on its side. To that end I think I'll open a discussion about what experiments need to be done to demonstrate various proposed CO2 heating effects and thus ideal climate sensitivity. Things like CO2 in a box experiments but done such that convection can be eliminated. IR and UV forcing of water is another. etc etc.

Mar 13, 2014 at 7:52 AM | Unregistered CommenterMicky H Corbett

Hi Richard,

Thanks for your direct response to my question, most refeshing.

So taking on board your reply and considering the red boxes which represent the "official" IPCC position.

You stated the Bish has mislabelled the red ranges, the official range in the summary to policymakers. The ranges of the red boxes are the 5-95% confidence interval.

Lewis' median value clearly lies below the official IPCC range. Given the importance attached generally in statistics to comparing a value to the confidence interval to decide whether to accept or reject a hypothesis, it would appear (to first order quick look anyway) that the difference is significant at the 90% CI level. It would be interesting to see if Lewis' median value falls outside the IPCC p2.5-p97.5 range.

I cannot see any way to legitimately describe these distributions as similar. Given that they are skewed and the bulk of the pdf in Lewis' result is below the official IPCC 5% level I think the only proper way to describe the difference is "significant". Perhaps you could comment on that.

Also, given what you say that the differences in the Bish's plot would be increased if the correct baseline were used, would the median for the IPCC red boxes in the plot fall outside the Lewis 17-83% range and what would happen to the overlap of the 17-83% intervals? Perhaps you could comment on this. (Eyeballing the plot, I think they would be non-overlapping). Again, I think the only proper way to describe these differences would be "significant" and certainly not as "similar".

And note I have not mentioned mean anywhere in my posts. I am fully aware of the importance of the median for reporting skewed distributions. Not sure why you mentioned that.

Look forward to your further comments.

Mar 13, 2014 at 7:59 AM | Registered Commenterthinkingscientist


I saw that comment of Eds (the climate too big can't experiment) in his back and forth with Clive and this highlighted just how crap climate science is where observation is always trumped by simulation!


Mar 13, 2014 at 8:03 AM | Unregistered CommenterMailman

Otherwise, ECS is a concept of doubtful validity. I ask time and again for the source of it as a defensible concept. No answer. It would be nice to know why so many people accept it apparently without question.

If the water in my kettle boils after five minutes from cold, how hot will it be after seven minutes?

Mar 12, 2014 at 9:49 PM rhoda

Mar 12, 2014 at 11:55 PM not banned yet

I think you entirely missed rhoda's point. Rhoda is always banging on about being just an Oxfordshire housewife but I rather suspect that her understanding of basic physics is much more profound than yours or mine.

The answer is that if after five minutes the water is at 100°C, then after seven minutes it will be at . . . . . . . . . . . . . . . . 100°C.

I've started to read through the Lewis/Crok report and I'll be interested to learn how much of existing "climate science" they take as providing a foundation.

We are dealing with a super-complicated nonlinear system, probably simultaneously exhibiting chaotic behaviours on hugely varying timescales (atmosphere, ocean).

Even the notion that ECS is a single-valued, deterministic function of CO2 seems to me to be an assumption whose validity is very far from obvious.

Mar 13, 2014 at 8:51 AM | Registered CommenterMartin A

Actually, neither the mean or the median is important in a skew - only the mode. Unless folk are mixing up median and mode.

Of course these are very nice, very intelligent people who are also very aware of the huge gaps in their knowledge about natural variability, clouds and aerosols and also, you'd assume, aware that a hindcast is not a validation of a model and cannot possibly give anyone any confidence in future projections by itself and of course they are also aware that frequentist stats cannot possibly be used on a handful of any data whatsoever but most especially data pre-selected by a pseudo-Bayesian process with extremely biased priors; so talking about 5% and 95% confidence limits is pure and utter drivel.

What a pity such nice people are proven wrong all the time yet seem utterly incapable of admitting it and what a pity they so often just make stuff up and pretend there is some science or data to support it. Especially a pity when energy policy needs the best policy advice, not just a collection of pessimistic gut feelings based on a show of hands of those who were invited to attend the meeting - all of whom are benefit from a pessimistic narrative, unlike the rest of the country who need their industries not to be crippled by high energy prices and who may need to choose between heating and eating. So difficult to just say "we really don't have a clue" when you've been teaching/preaching the wrong thing for 20 years too isn't it? But jolly, jolly where's the next climate change conference - in a nice hot place I hope? And of course there surely an award coming up for the most hypocritical, self-righteous prig of the year.

Mar 13, 2014 at 9:21 AM | Unregistered CommenterJamesG


The line you adopted in reaction to Lewis/Crok on publication day didn't advance the debate. It was a diversionary tactic. As a journalist, I'm not in a position to speculate on who used who - we're "used" by everyone :)

Mar 13, 2014 at 10:27 AM | Unregistered CommenterAndrew

This is a long post, but I think worth it.

I would like to try and put the difference between the Lewis and IPCC values into a real world context. As some regular BH readers may recall, I work in the oil industry. I do a lot of work in stochastic modelling and have a lot of experience in oil & gas reserve uncertainty and its reporting.

Let us imagine the IPCC were a stock exchange listed oil company, perhaps in the UK or US. Its reported reserves affect the share price of that company, its ability to raise capital for funding development and so forth. The future economic value of that oil company depends on the accuracy of its reserves reporting.

Similarly, there is a forward economic outlook that can be calculated based on the reported value of climate sensitivity and its range of uncertainty. Think Stern report, calculating huge future economic gains or losses worth trillions of dollars based on economic forecasts and adaptation/mitigation strategies using these numbers.

In oil company terminology the IPCC has “booked” its reserves numbers for climate sensitivity. In the oil industry there are a number of accepted (and regulated) ways of booking reserves, which are of course uncertain owing to having to be analysed and estimated based on sparse real world observations and complex computer models. Just like the IPCC and climate models.

In the oil industry we work with (cumulative) probability numbers, just like we are discussing here. In the oil industry we actually report our cumulative integrated from the largest to the smallest value (it’s just a convention) so they are reversed compared to the statistical reporting used here by Lewis and the IPCC. We define our uncertainty points as P90 (smallest/lowest) through P50 (median) to P10 (largest), so our confidence interval is 10-90%. Note that what I am about to say would be even worse for the IPCC numbers because they report 5-95% intervals.

Reserve booking is in categories. There is a 90% chance of exceeding the P90 reserves and these are typically referred to as “Proven”. There is a 50% chance of exceeding the P50 reserves and these are termed “Probable”. And there is a 10% chance of exceeding the P10 reserves and these are termed “Possible”.

Imagine an oil company has reported to the shareholders and stock markets its booked reserves and reported its minimum proven reserves. They then commission an independent review of their reserves and the new analysis determines that the new P50 (median) is now below the old “Proven” reserves. All hell would break loose. If a company made such an announcement, or was found to have misclassified its reserves in this way it would be in serious trouble and its credibility would be seriously questioned.

This is exactly what happened to Shell in 2004. Shell was forced to downgrade its reserve numbers. It paid £87.2 million in fines to the regulators in the UK and the US alone. The Daily Telegraph reported:

“An investigation by the SEC - launched in January after Shell admitted its reserves were 20 per cent smaller than previously thought - found the company had violated reporting, record-keeping and anti-trust rules.”

If that had been a small, AIM- listed oil company in the UK with just a few assets the consequences of making an announcement that moved the companies “Probable” (P50) reserves down to below its previously stated “Proven” (P90) reserves would be likely catastrophic to the market perception of the company. It would probably trigger an investigation, the shares would be suspended from trading and there would be resignations from the Board of Directors – probably the chief executive and the technical director. If the board had failed to announce these changes to the market and tried to cover it up there would probably be a criminal investigation if they were discovered. On re-commencing trading in the shares, the share price would plummet.

The difference between Lewis and the IPCC is like a reserve booking problem. If we accept Lewis’ figures then the new "Possible" P50 (median) is now below the previously booked “Proven” reserves. And in the analogy, the IPCC proven is not 90% like it is in the oil industry, but 95%. If Lewis is right, those are serious consequences – economic futures will need to be re-evaluated and trillion dollar mitigation or adaptation plans revised. All this hand waving by academics that “the ranges overlap” is just nonsense. In the real world the IPCC shares would already be suspended from trading and investigations by the regulator have started.

Mar 13, 2014 at 10:44 AM | Registered Commenterthinkingscientist

thinkingscientist, the IPCC can of course make whatever exaggerated claim they like. There is no moral hazard. There is no incentive to honesty or to full disclosure.

Mar 13, 2014 at 11:02 AM | Unregistered Commenterrhoda

Heh, ts, in the real world those measures are in place to lessen the catastrophe when reality collides with expectation. What is the equivalent measure in climate science and policy?

Mar 13, 2014 at 11:14 AM | Unregistered Commenterkim

Very well put, thinking scientist at 10:44 AM.

Such an investigation of the IPCC would be a good sign and I dream of the day that it takes place. A great deal of documentation relevant to such a review is building up, and powerful commentaries on it exist. The work of Donna Laframboise on the procedural, loud-mouth, and deliberate deceit aspects is well known. The NIPCC reports are exploring scientific research and observations that seem, one need not wonder why, to not figure very highly if at all in the IPCC version of the world and what we know of it. In between, Tim Ball's new book, 'The Deliberate Corruption of Science' promises (I have only just got a copy of it) to provide a penetrating narrative linking sloppy science with smart-alec politics - two of the hallmarks of the campaign to alarm us all about CO2 and climate. And what a disgraceful blot on our history that campaign has turned out to be. The audit I dream of would be starting from that insight and seek to expose and record in some formal manner just how it managed to get so far, and do so much harm. It might also seek to highlight ways in which we might hope to protect ourselves from anything like it in the future.

Mar 13, 2014 at 11:46 AM | Registered CommenterJohn Shade


Some comments on the points you make in your response to thinking scientist:

1. Agreed that my projection 'likely' ranges overlap a bit with the main AR5 ones – which represent the CMIP5 models 5-95% statistical fit range. But the central cases for my and the main AR5 projections lie outside each others 'likely' ranges.

2. The Bish has not made a mistake in saying that the IPCC main warming projection red boxes are 17-83% ('likely') ranges and means based on the ensemble of CMIP5 models. The post says "based on the ensemble of CMIP5 models", not that it represents the 17-83% ranges of the CMIP5 ensemble. The AR5 Technical Summary says, in relation to 2081-2100 projections, "the 5 to 95% range of CMIP5 is assessed as 'likely' rather than 'very likely' based on the assessment of TCR." [TS 5.5.1]. So the red boxes are regarded in AR5 as 'likely' ranges.

3.Neither has the Bish made a mistake in the baselines, although I can see why you think he might have. As the footnote says, "The best estimates and likely ranges are not identical to those given in the Lewis and Crok report (although the TCR best estimate is virtually the same)". The 2.1 C warming from 2012 to 2081-2100 given in the report was calculated using the simple TCR multiplier plus warming-in-pipeline method, and rounded upwards. The ranges I supplied for the figure in this post use the more sophisticated 2-box model method referred to in the report, are unrounded and adjust the baseline from 2012 to 1986-2005 (by 0.76 - 0.61 = 0.15 C: 0.19 C uses a 0.8 C rounded figure).

4. Agreed that for skewed distributions means should not be compared against medians – in fact means should not be used as a central measure at all. But the CMIP5 ensemble range is not skewed (for RCP8.5 it is 2.6 C to 4.8 C, with a mean of 3.7 C), so one would expect the median to be the same as the mean. That is consistent with the distribution of TCRs for CMIP5 models given in Table 9.5 of AR5: the mean is 1.83 C; the median is almost the same at 1.80 C. Therefore, the comparisons are fair as they are essentially medians against medians.
It is odd that the CMIP5 projected warming distribution is not skewed, unlike my distribution based on AR5 forcing etc. data (it's not from the LC report - that doesn't give ranges for projected warming). The CMIP5 range should be similarly skewed if it represented actual uncertainty about the climate system's relevant properties. The fact that it isn't suggests to me the influence of model tuning and/or model selection.

So I'm afraid that your conclusions are all invalid. But thanks for raising these points; clarifying the position in regard to them is helpful.

Mar 13, 2014 at 12:00 PM | Unregistered CommenterNic Lewis


Thanks for that, I'm sure you are totally correct. However, the whole thing is a con because the temperature record is a closely guarded fantasy. This so called sceptical paper has been publicised to show that the sceptics are in the same ball park (give or take) and that the science is basically sound which it absolutely isn't.

My science page.

Mar 13, 2014 at 12:09 PM | Unregistered Commenteresmiff

esmiff - I disagree.

Far from showing the science is "basically sound", IMO the paper is showing that there are sceptics who can argue within the terms of debate set by the IPCC and expose significant errors in both substance and presentation.

Mar 13, 2014 at 12:36 PM | Unregistered Commenternot banned yet

nby: very well said. And that takes me back to Martin A (Mar 12 at 10:00 PM):

As I have said before, ECS seems to be the one bit of "climate science" that even sceptics regards as valid.

I think 'valid' may be too strong. But sceptics like Dick Lindzen and Nic Lewis think it's important and cogent enough as a line of argument to join the discussion with a view to improving the answer(s) given. After all, if a policy maker asks "If we add more CO2 what will be the effect on temperature?" it's a pretty fair question. Nic is showing that the current IPCC answer is well off-centre even on its own terms, based on real world observations. A very important contribution.

Mar 13, 2014 at 12:54 PM | Registered CommenterRichard Drake

It is noteworthy that Nic did not say to Myles

'Why should I make the data available to you, when your aim is to try and find something wrong with it.'

Mar 13, 2014 at 1:23 PM | Registered CommenterPharos

Pharos: Yeah, that has to be filed under "Great crimes the deniers didn't commit". Funny that.

Mar 13, 2014 at 1:27 PM | Registered CommenterRichard Drake

However "... when your aim is to misrepresent it" might have been a justified concern...

Mar 13, 2014 at 1:54 PM | Unregistered Commenternot banned yet

Double heh heh. One 'equivalent measure' is Nic's response to Richard. Richard, the scare has been exaggerated. Just stop it.

Mar 13, 2014 at 2:20 PM | Unregistered Commenterkim

I'm reminded of an old favorite line: 'Oh, sit down!'

Mar 13, 2014 at 2:22 PM | Unregistered Commenterkim

A further point can also be made about the comparison of the Lewis versus IPCC numbers for the various Representative Concentration Pathways (RCP).

Myles Allen (and Richard Betts) seem keen to assert that there are overlaps between IPCC and Lewis’ numbers, that they are similar and therefore that it is “business as usual”. Lewis’ figures are “consistent with” the IPCC. At least that is what they are trying to dissemble too.

But looking at the Bish’s plot at the top of the post something else becomes very clear. The RCP pathways are defined in terms of W/m^2, the number after RCP corresponding to the assumed W/m^2 of global warming in the scenario.

If we assume Lewis’ figures are correct and we also believe that the possible scenarios presented by the IPCC are the only reasonable ones for the future emissions, then we find that the IPCC RCP8.5 is actually only as bad as the RCP6.0, using Lewis’ figures. Using Lewis’ figures RCP6.0 is actually better (safer?) than RCP4.5 and RCP4.5 looks like RCP2.6.

So after all the hand waving and dissembling we can actually see that if Lewis is correct all the outcomes shift to the next RCP scenario down (and even better in the case of RCP6.0).

Good news, shurely?

Mar 13, 2014 at 4:56 PM | Registered Commenterthinkingscientist


You mentioned the key point:

"After all, if a policy maker asks "If we add more CO2 what will be the effect on temperature?" it's a pretty fair question."

So what data and evidence would you use that CO2 has an effect on temperature? Based on what evidence there is out there at the moment the answer is between "no effect and don't know - I'll get back to you when I've done the proper experiments" which will happen somewhere over the Rainbow at this rate.

All there is is theory, and not the tightest theory at that. But for something like climate impacts, which is basically an applied engineering field, theory is no subsitute for data. Even more so when the outcome directly affects people's livelihoods and their pockets.

Climate science is addicted to theory and governments are chucking money at it purely to feed its addiction. Scientists have careers purely to cater for self-indulgence and navel-gazing. The money gushes out to computer models and study papers and nothing appears to go into experimentation and actually finding stuff out.

And here we are getting sucked into the game of trying to define Climate Sensitivity. We should be better than this.

You should go look up the Diagonal Steam Trap by Crawford Howard, a Northern Ireland poet who writes very funny verses. Climate Science is like the Diagonal Steam Trap.

Mar 13, 2014 at 4:58 PM | Unregistered CommenterMicky H Corbett

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