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« Cox and Ince on the scientific method | Main | Curbs on FOI »

+++Climate sensitivity is low+++

Matt Ridley has an article in the Wall Street Journal which is of incalculable importance.

Mr. Lewis tells me that the latest observational estimates of the effect of aerosols (such as sulfurous particles from coal smoke) find that they have much less cooling effect than thought when the last IPCC report was written. The rate at which the ocean is absorbing greenhouse-gas-induced warming is also now known to be fairly modest. In other words, the two excuses used to explain away the slow, mild warming we have actually experienced—culminating in a standstill in which global temperatures are no higher than they were 16 years ago—no longer work.

In short: We can now estimate, based on observations, how sensitive the temperature is to carbon dioxide. We do not need to rely heavily on ­unproven models. Comparing the trend in global temperature over the past 100-150 years with the change in “radiative forcing” (heating or cooling power) from carbon dioxide, aerosols and other sources, minus ocean heat uptake, can now give a good estimate of climate sensitivity.

The conclusion—taking the best observational estimates of the change in decadal-average global temperature between 1871-80 and 2002-11, and of the corresponding changes in forcing and ocean heat uptake—is this: A doubling of CO2 will lead to a warming of 1.6°-1.7°C (2.9°-3.1°F).

Warming at a snail's pace is a small problem, not a big one.

The Wall Street Journal is paywalled, unless you go via Google. Click here and then click on the first entry on the search results.

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Reader Comments (56)

Warming at a snail's pace is a small problem, not a big one.

Considering that most of the world's population live in a relatively cold northern hemisphere, 1.6C of warming is a positive outcome. (though I am still sceptical of CO2 contributing more than 0.25C warming per doubling).

Regardless, this isn't turning out to be a good week for the alarmists.

Dec 19, 2012 at 8:14 AM | Registered Commenterlapogus

And of course low sensitivity matches observations on global ice, global temps, sea levels and history of climate optima. With the need for urgent action removed, the current alarmists can repent at leisure while a new generation invested in no more than curiosity itself, continues the work of those so far proved right.

Dec 19, 2012 at 8:16 AM | Unregistered Commenterssat

Given that another reviewerer of AR5
points out no robust trend in global water vapour, it seems that the IPCC is in very hot water.

Dec 19, 2012 at 8:18 AM | Unregistered Commenterconfused

lapogus: your estimate is an exaggeration because CO2 band IR cannot be emitted from the surface when you have radiative equilibrium between two equal temperature emitters both near black body in the main GHG bands.

Dec 19, 2012 at 8:35 AM | Unregistered CommenterAlecM

Excellent article from Ridley. I have been communicating with Nic Lewis for several weeks now and it is really impressive how much he has learned about all the different approaches to estimate climate sensitivity. It will be really interesting to see how AR5 is going to deal with this. If they acknowledge that the best estimate for climate sensitivity is 1.6 degree Celsius (instead of 3) than they have to lower their likely range (now 2 to 4.5) too. This is the range that has been (kept) constant for more than 30 years. If they do this, it is the end of climate alarm as we have seen it for the past decades. If they don't do it, AR5 will be severely criticized (again) as having ignored crucial peer reviewed literature. The AR5 authors have some tough choices to make.

Note: This best estimate of 1.6 is based on the assumption that aerosols cool less than we thought before. However the sun still plays a minor role in this estimate. Two highly relevant papers by Nir Shaviv show the role of the sun is larger (Nir J. Shaviv (2008); Using the oceans as a calorimeter to quantify the solar radiative forcing, J. Geophys. Res., 113, A11101, doi:10.1029/2007JA012989 and Ziskin, S. and Shaviv, N. J., “Quantifying the Role of Solar Radiative Forcing over the 20th Century”, Astrophysics and Space Science.) In the 2008 paper he shows that during a 11 year solar cycle the oceans take up more heat than you would expect purely on the basis of the Total Solar Irradiance differences. The amplification factor is around 6 or 7. In the 2011 paper he then calculates that the sun must have contributed 0.3 C tot the total warming of around 0.8 C. Climate sensitivity then comes down to slightly under 1 C.

Dec 19, 2012 at 8:43 AM | Unregistered CommenterMarcel Crok

Lapogus: "...sceptical of CO2 contributing more than 0.25C warming per doubling."

And you may be right given that CO2 deflects half incoming IR in its absorption bands back to space.

Dec 19, 2012 at 8:52 AM | Unregistered Commenterssat

Good news for humanity if there is no "C" to go with AGW..... so many Alarmists will be in despair, though..... they didn't want to "waste a good crisis" but the Alarm Bandwagon may soon need new causes.

Dec 19, 2012 at 9:02 AM | Registered CommenterSkiphil

I think were missing the point here: the IPCC is not a scientific body but a political one. Therefore when the science hypothesis of global warming is at odds with the observations, the contributing scientists will get the blame; the politicians/administrators will stay on.

Dec 19, 2012 at 9:02 AM | Unregistered Commenteroebele bruinsma

Yeah, well, if it's true how can anyone explain why the Greenland and Himalayan glaciers are all melting away?

We'll probably have to think of some new problem to tackle, like, oh, I don't know, how about carbon?

Yeah, that will do - we can say it was carbon all along, just not CO2! See, we were right! All those newpaper reports always went on about carbon footprints, we can pretend we meant black carbon all along!

And most industrial countries are already pretty clean compared to last century, so we can claim that we've already fixed the Arctic problem by reducing black carbon! That's why temps are flatlining!

And we can save all the polar bears by getting rid of dirty coal power stations, and using shale gas! Brill!

But where would all the soot come from in the Himalayas? I know, we can blame wood burning in India! So to save the glaciers, we can help India invest in nice clean energy, like electricity!

Dec 19, 2012 at 9:05 AM | Registered Commentersteveta

Exactly what most of us have been saying for years. All observational based climate sensitivity studies indicate low climate sensitivity. Question is will the IPCC take note of these studies or slip in a study casting doubt, before the March 2013 deadline so reviewers don't have a chance to comment?

Dec 19, 2012 at 9:08 AM | Registered Commentermangochutney

Mangochutney - I think you are right, after all they have already instigated that strategy with solar forcing.

I also think oebele bruinsma hits the nail on the head - this is not about science at all. Science is just a cloak for a cause. It doesn't matter that the emperor has no cloak, or any garments at all.

Dec 19, 2012 at 9:24 AM | Unregistered CommenterRetired Dave

I can't see how this is IMPORTANT.

It shows that the IPCC are most likely wrong about a critical part of the argument. This is so usual as to not excite comment. Steve McIntyre kicked off this approach in 1998 by pointing out that the Mann hockey stick was mathematically incorrect - the late John Daly had been pointing out inconvenient truths about sea level to the Australian Met Office for some time before that. Each of these instances (and many more besides at later times) were readily provable failures of the AGW hypothesis. And what has happened over the past 15 years? A bout of fingers in ears and a collective 'la-la-la'.

Humans work in socially-mediated groups, as Charles Mackay pointed out. They lose their heads in a crowd, and only come to their senses slowly, and one-by-one. We are not there yet.

Dec 19, 2012 at 9:33 AM | Unregistered CommenterDodgy Geezer

Even for a lukewarmer like me, Lewis' estimate of 1.6°-1.7°C for a doubling of CO2 seems surprisingly precise and surprisingly high, given the rather poor correlation between recent increases in atmospheric CO2 content and the published estimates of recent global surface temperature trends. With such a wide array of different - and in many cases poorly quantified, poorly understood or even unknown - natural and anthropogenic influences on climate and surface temperature - how can one derive a meaningful figure for 'sensitivity' from just considering CO2 and aerosols? Of course, it may suit the IPCC to limit the discussion in that way, but that's no reason for enquiring scientists to blinker their own vision.

Dec 19, 2012 at 9:37 AM | Unregistered CommenterColdish


I think this is not meant to represent the "likely" range. Just a feel for where the kind of numbers where the mode should be.

Dec 19, 2012 at 9:42 AM | Registered CommenterBishop Hill

I am with Dodgy Geezer on this one. The Catastrophe Scare reached its peak with Climategate and the failure at Copenhagen...with Copenhagen being the more important event. We are seeing a slow overall winding down on the catastrophe front but any one piece of science or politics will not make any huge step-change.
We are stuck with the consequences for years. There has never been anything quite like it in the history of Science.

Dec 19, 2012 at 9:47 AM | Unregistered CommenterJack Savage

Aerosols always were the "ivariable fiddle factor" used in models to put "wiggles" in the models output to help them match the temperature record.
Just like water vapour "positive feedback" was used to magnify CO2's limited effect on temperature.

I'm sure that Richard Betts would wish to comment on this and Matt Ridley's article.

Dec 19, 2012 at 9:48 AM | Unregistered CommenterDon Keiller

Mark Lynas has asked Richard to comment.

Dec 19, 2012 at 9:58 AM | Registered CommenterBishop Hill

The conclusion—taking the best observational estimates of the change in decadal-average global temperature between 1871-80 and 2002-11, and of the corresponding changes in forcing and ocean heat uptake—is this: A doubling of CO2 will lead to a warming of 1.6°-1.7°C (2.9°-3.1°F).

It's a guess no better than a guess from a climate model. The problem remains the same. We have no way of empirically, accurately measuring any of the parametres mentioned in this article or for that matter, the effect of the sun. Yes there are correllations but correllation a cause does not make.

Dec 19, 2012 at 10:11 AM | Unregistered CommenterStephen Richards

Alarmist spinners (in Germany?) picked out the nice round number of 2C for the temperature rise we must stay beneath. It has no other merit as far as I know, but it has been widely disseminated as a piece of pseudo-science that campaigners can readily use along with scare-talk of tipping-points and of course the end of life as we know it. Therefore publicity for 1.6C as a credible value for a CO2 doubling is a welcome counter that will have extra edge thanks to the aforementioned and fatuous 2.

I'm with lapogus in suspecting that 1.6 is on the high side even if it is an 'all else being equal' type of guesstimate, but then the whole thing about guessing small changes in temperatures 100 years or so ahead is something of a can of somewhat unsettled worms.

Dec 19, 2012 at 10:15 AM | Unregistered CommenterJohn Shade

The article by Ridley, or at least part of it, is reproduced at Greenie Watch:

Dec 19, 2012 at 10:22 AM | Unregistered CommenterJohn Shade

Is Mr Lewis going to make his calculations public? Standard practice is to submit these sorts of results to a journal before announcing them in a major news outlet.

In fact I worry that by taking this route Matt Ridley could undermine Mr Lewis' work. To the general public this kind of article may sound a bit crackpot - "Retired hobbyist confounds scientists by disproving fundamental climate theory - trust me!".

Show us the full scientific write-up, Mr Lewis, then we'll be more comfortable.

Dec 19, 2012 at 10:41 AM | Unregistered Commentertilting@windmills

"The rate at which the ocean is absorbing greenhouse-gas-induced warming......"

And how does the inanimate ocean differentiate that type of warming, & any other type of warming?

Dec 19, 2012 at 10:52 AM | Unregistered CommenterJoe Public

Actually, the "general public", left to its own devices, would understand and support Nic Lewis since what he is saying chimes with what reasonable people instinctively understand about the world they live in.
Since there never has been in several million years "runaway global warming" and the weather has done nothing especially dramatic over the lifetime of most of us and there is no observational evidence that it is currently doing anything out of the ordinary, it is only the partisan bleatings of the hyperactive Chicken Littles (can chickens bleat?) with their rather poor imitations of Corporal Jones and Private Fraser that is spreading alarm and despondency among the lieges.
"Retired hobbyist confounds scientists by disproving fundamental climate theory ..." sounds more like the professional sneering that we are used to hearing from ZDB and the other vacuous trolls that drift in and out of the room occasionally.

Dec 19, 2012 at 11:04 AM | Registered CommenterMike Jackson

@Jack Savage

...We are stuck with the consequences for years. There has never been anything quite like it in the history of Science....

It seems invidious to take issue with someone who asserts that he agrees with me - but I fear that the History of Science is less anodyne than you may suppose. Thomas Kuhn pointed this out in the 1960s, and what he said was simply a retelling of what Roger Bacon had noticed in the 1260s. It is actually the norm for Science (and most aspects of human life) to proceed by following authority, and NOT to think outside the narrow bands that this allows.

Just taking the last century, we had the Piltdown controversy in the 1910s, where the paleontological establishment enforced an incorrect lineage which suppressed progress for 40 years, by 1930 we had Continental Drift being rigorously vilified and ignored by the geologists until the 1960s, and in the early 1980s the H. Pylori cause of peptic ulcers was successfully rejected for the best part of 20 years, nearly ruining the careers of Warren and Marshall, who were pushing the correct diagnosis against the establishment drug companies.

Almost ALL the history of science is the history of establishment-enforced error and the maintenance of funded interests against lone brave individuals who are usually denied any recognition when finally proven right.

It's a wonder that we manage to progress at all. Of course, if it were up to the Greens, we wouldn't...

Dec 19, 2012 at 11:04 AM | Unregistered CommenterDodgy Geezer

First things first. You guys are all deniers. That is why you are so willing to believe in good news.

Second, expect skepticalscience to rebut this article with a pre-debunking.

Thirdly, this is just a theory. If, as a result of what was exposed in Climategate, those scienctists who held their peace earlier witnessing the shenanigans of 'the Team' had now gained some moral high ground inside the IPCC machine, the 'attacks' on the IPCC would expose their position. They would be used cynically by 'the Team' to turn the tide back.

Dec 19, 2012 at 11:09 AM | Registered Commentershub

I've deleted a couple of comments. Please keep this thread to the contents of Matt Ridley's article rather than general complaining about what has gone before.

Dec 19, 2012 at 11:15 AM | Registered CommenterBishop Hill

Money quote ...

... given the [IPCC's} record of replacing evidence-based policy-making with policy-based evidence-making ...

tilting@windmills asked to see Nic Lewis' calculations. Suggested readings ...

Nic Lewis on Statistical errors in the Forest 2006 climate sensitivity study
The IPCC’s alteration of Forster & Gregory’s model-independent climate sensitivity results
Questioning the Forest et al. (2006) sensitivity study

Dec 19, 2012 at 11:20 AM | Unregistered CommenterSpeed


Dec 19, 2012 at 11:26 AM | Unregistered Commentercedarhill

I think taw has a point, though. What is sauce for the goose is sauce for the gander, and I would far rather have learned of this via a posting from Nic on CA or in a publication, with stats attached, than from an article in the WSJ. Leave this kind of approach to Mann, Muller or dare I say Lewandowsky.

Dec 19, 2012 at 11:43 AM | Unregistered CommenterDavid S

I have a question for Lewis:

What is the role of 'natural internal climate variability' in the calculation of climate 'sensitivitiy' as currently performed by the IPCC?

The formula seems to be: temperature raise caused by CO2(doubling) + temperature rise caused by 'feedbacks' = total rise.

Clearly, there is no accommodation of natural variability in this formula, if I am indeed summarizing it correctly.

Dec 19, 2012 at 11:48 AM | Registered Commentershub


Dec 19, 2012 at 12:09 PM | Unregistered CommenterJustice4Rinka


"The formula seems to be: temperature raise caused by CO2(doubling) + temperature rise caused by 'feedbacks' = total rise."

The formula is more like:
(forcing due to CO2 + other forcings + internal variability) x sensitivity / (1 - feedback) = ocean warming + surface warming.

There are a lot of unknown and adjustable parameters. The elephant can indeed wiggle his trunk.

Dec 19, 2012 at 12:40 PM | Unregistered CommenterNullius in Verba

This is silly and very dangerous nonsense. It plays into the hands of the 97% of professionals who disagree. If Hansen says he's wrong, then he's damned well wrong, and now he has accepted that Hansen is capable of forecasting the future. The idea that it is possible to make predictions on the future of the earth's climate with its hundreds of interacting variables and dimly known proxified past is farcical.

What happened to cosmic rays in this little fantasy ?

I had no idea who Ridley was until I read about him here. Others may disagree, I am not trying to offend, but Hayek followers and the like have no credibility in Britain outside a lunatic fringe.

Dec 19, 2012 at 12:57 PM | Unregistered Commenteresmiff

To me this seems newsworthy. So given our national TV broadcaster is impartial on such matters perhaps Matt Ridley should make an appointment with the editor of Newsnight?

Dec 19, 2012 at 12:58 PM | Unregistered CommenterDolphinhead

Thanks niv. If one observes the IPCC AR4 temperature projections, there is a graph of multimodel averages (which we are familiar with) with one of the curves which is a 'year 2000 co2 constant' curve - the yellow one.

The yellow line shows no variability whatsoever. Which means, in the models, its contribution to the formula above should be minimal, or zero?

Dec 19, 2012 at 12:59 PM | Registered Commentershub

Sorry, but it has to be said:

"No Virginia, There Is No CO2 Climate Sensitivity"

The public is not being well served, in the present insane political environment.

Dec 19, 2012 at 1:34 PM | Unregistered CommenterHarry Dale Huffman

Brilliant to see Murdoch, Ridley and Lewis on such great form here, after a trying year! And the host here, for removing messages not on the subject - the most important subject in the science, let's remember, for on it all else in the turgid IPCC narrative depends. No time for me to process the details, as with so much else, but blessed to know it's in such good hands. Indeed, as Tiny Tim would surely put it at this juncture, God bless us, every one :)

Dec 19, 2012 at 1:36 PM | Registered CommenterRichard Drake

David S wrote, " ...I would far rather have learned of this via a posting from Nic on CA or in a publication, with stats attached ... "

I guess you missed this one.

Dec 19, 2012 at 1:54 PM | Unregistered CommenterSpeed

Thanks Speed, if Matt's article is a rehash of the CA paper I stand corrected; I had thought that it was a new piece of work.

Dec 19, 2012 at 2:34 PM | Unregistered CommenterDavid S

I suppose that I should be grateful to anyone who stands up and attempts to prove that the gubbins being promoted as truth by "the opposition" is wrong. I also suppose that we have no alternative but to attempt to counter opposition claims when we see the political decisions that use them as justification.
However as one or two have attempted to point out; the truth is that Matt Ridley is just as wrong as the IPCC.
The correct position for both sides to take would be to admit that with our current limited knowledge of exactly how our climate works, it is close to insanity to make predictions and spend billions on dealing with those predictions.

Dec 19, 2012 at 2:48 PM | Registered CommenterDung

Just a thought on "greenhouse-gas-induced warming." If GHG warming is LWIR, how does it heat the ocean? I was under the impression that LWIR penetrates a millimetre or so into the water and serves only to increase evaporation. This in turn will increase heat transport to the upper atmosphere. Am I missing something?

Dec 19, 2012 at 2:48 PM | Unregistered CommenterTim Bromige


However as one or two have attempted to point out; the truth is that Matt Ridley is just as wrong as the IPCC.

Yeah, Matt and Nic are so dumb, compared to some other BH contributors, aren't they?

Dec 19, 2012 at 2:53 PM | Registered CommenterRichard Drake

Speed - this is actually a new piece of work, not Mr Lewis' previous entries. Fortunately he's just put his work up on BH :-)

I do stand by my previous comment, even if I couched it in a rather forthright way. Mr Lewis has made what appears to us a credible contribution to scientific knowledge. Let it be published, debated and reviewed, then covered in the WSJ. Not the other way round. That way, if it turns out to be good science, nothing is lost. If it turns out there is a mistake (perhaps unlikely, but possible) then red faces are avoided all around.

Let's keep at least as high standards as those we would point fault with. I think that could help things. Call me old-fashioned/naive...

Dec 19, 2012 at 3:18 PM | Unregistered Commentertilting@windmills


It's interesting to ponder the question of whether a journal would accept an article based on these findings. In some ways it's a critique of the IPCC's distillation of the science rather than new findings.

Dec 19, 2012 at 3:42 PM | Registered CommenterBishop Hill

Richard Drake

tsk tsk, lets stay on topic shall we.

Dec 19, 2012 at 4:11 PM | Unregistered CommenterDung

tilting@windmills wrote, "Mr Lewis has made what appears to us a credible contribution to scientific knowledge. Let it be published, debated and reviewed, then covered in the WSJ. Not the other way round."

Which will take how many years? What's the harm in doing it Nic's way?

Dec 19, 2012 at 4:20 PM | Unregistered CommenterSpeed

Come now, Bishop. I think you do the work of Mr Lewis a disservice!

Don't know if you don't try ;)

Dec 19, 2012 at 4:28 PM | Unregistered Commentertilting@windmills

I think it was McKitrick who couldn't get a critique of the IPCC process published in a climate journal because it was not new science.

Dec 19, 2012 at 4:38 PM | Registered CommenterBishop Hill

I said Matt Ridley was wrong.

Just about the only person in the climate change debate who is always right is Steve McIntyre because he does not predict anything, does not express a belief one way or the other; he just deals with the facts and the math.

Dec 19, 2012 at 4:40 PM | Registered CommenterDung


For the avoidance of doubt I'm referring to Mr Lewis' calculations and not Matt Ridley's commentary.

In this case I think the more comparable example is the paper on Antarctic warming that Mr Lewis and others wrote. Rather than being a "new finding" as such, it used existing data and some statistical methods to criticise an existing finding. And it was published in Journal of Climate - three cheers!

Dec 19, 2012 at 5:11 PM | Unregistered Commentertilting@windmills

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