Bad Science Bait & Switch Climate Change Global Warming Media Non-Science Science Rules

Roger Harrabin : One Degree Is Not Enough

I’ve been letting my peers know of my displeasure regarding the article in New Scientist by the BBC journalist Roger Harrabin :-


Hi Guys,

Just thought I’d run the flag up for the fact that an allegedly sceptical journalist, Roger Harrabin, has written a poor opinion piece in the popular science magazine New Scientist.

Annoyed ? We could perhaps be :-



Joseph Romm from got back with this :-


Thanks. I might hit this.
Harrabin is quite lame.
Note that on the BAU path, we are almost certainly headed toward 800 to 1000 ppm by 2100.
I have a lot of links on that here

Joseph Romm
Senior Fellow
Center for American Progress


Kevin Grandia of got back too :-


Thanks for this Jo. I’ve passed it on to one of our writers.

Sent from my mobile device

Kevin Grandia
Managing Editor

DeSmogBlog’s much anticipated book, “Climate Cover Up: the crusade to deny global warming” is now available on Amazon and Barnes and Noble – get your copy today!


Rich Hawkins of was more critical :-


It’s down the meaning of “basic physics”. Without any feedbacks or other GHGs, the consensus IS that a CO2 doubling would warm the world by 1 degree.

Sensitivity comes out as 2-4.5 degrees because the system isn’t basic, and includes feedbacks.

This is what he’s implying the skeptics dispute, in his final paragraph. Other GHGs and forcings are outside the sensitivity measure as you know.

It’s sort of sloppy but I don’t think it’s a terrible piece. Maybe I’m wrong.



Not quite so fast, Rich my boy :-


Hi Rich,

Most of the Global Warming at the moment is caused by the rise in Carbon Dioxide concentrations in the Atmosphere. Therefore, the Transient Climate Response is pretty much due to Carbon Dioxide on its own, as I understand it (correct me if I’m wrong).

This is in the IPCC Fourth Assessment Report, Technical Summary, TS.4 “Understanding and Attributing Climate Change” :-

“The range of transient climate responses (defined as the global average surface air temperature averaged over a 20-year period centred at the time of CO2 doubling in a 1% yr–1 increase experiment) among models is smaller than the range in the equilibrium climate sensitivity. This parameter is now better constrained by multimodel ensembles and comparisons with observations; it is very likely to be greater than 1 degree C and very unlikely to be greater than 3 degrees C.”

That’s the consensus, and that’s not 1 degree Celsius.

The Climate Sensitivity, as you rightly point out, is the total eventual temperature rise calculated from models and data to be associated with a doubling of Carbon Dioxide in the atmosphere. This is not 1 degree Celsius, as you say. Here’s what the IPCC say in the Fourth Assessment Report regarding Climate Sensitivity :-

IPCC AR4 [Fourth Assessment Report] Technical Summary TS4.5 “Climate Response to Radiative Forcing” :-

“A range for equilibrium climate sensitivity – the equilibrium global average warming expected if CO2 concentrations were to be sustained at double their pre-industrial values (about 550 ppm) – was given in the TAR [Third Assessment Report] as between 1.5 degrees C and 4.5 degrees C. It has not been possible previously to provide a best estimate or to estimate the probability that climate sensitivity might fall outside that quoted range.”

And that’s not 1 degree Celsius, either.

The way that Roger Harrabin writes that sentence, he is being weasel-ish, not only using the lowest value of the TCR, but rounding it down.

The Climate Change sceptics pick and choose which elements of Radiative Forcing they choose to accept, and which long-term Climate Changes they choose to accept. This is not the way to proceed.

Roger Harrabin seems to be trying to make an assertion that is not correct about the nature of the scientific consensus.



Rich just got back again :-


I’m not saying sensitivity is 1 degree and nor is Roger Harrabin. The warming you’d get from a doubling of co2 alone (without the fast feedbacks, water vapour and clouds etc.) would be 1 degree.

That’s what Roger is referring to, although I agree it’s not very clear.

This 1 degree doubling is obviously very artificial, as the water vapour etc. WILL change. Hence the 2-4.5 degree climate sensitivity figure, which includes the fast feedbacks: they add the extra 1-3.5 degrees (lots of uncertainty).

Harrabin is implying that the skeptics disagree with fast feedback part (Lindzen comes to mind) rather than the ‘CO2 is a radiative gas’ part.

I’m not sure they do all think this (for example Piers Morgan [Corbyn ?] doesn’t, although he’s REALLY loopy), but the savvy ones certainly do (Lawson et al.). This is possibly because it’s pretty easy to demonstrate the radiative nature of CO2 with a glass tube and an infrared camera (as Ian Stewart has done). Much stronger to play on the inherent uncertainty in both the fast (climate sensitivity) and slow (carbon cycle, long-term albedo etc.) feedbacks, a la Lawson’s ‘we don’t know how much the world will warm, how quickly or how much damage it will do… so let’s just wait and see’!



So, I felt obliged to reply :-


But Rich,

By saying “Most agree with the scientific consensus that basic physics means CO2 will warm the planet by about 1 degree C above pre-industrial levels.” about the Climate Change sceptics, Roger Harrabin is effectively making the claim that the “basic physics” means we will only get a total, eventual warming of “1 degree C”.

I assume he is talking about the climate models when he says this. But this is what I am unhappy about, as it does not match the data coming out of research based on paleoclimates.

Here’s a very recent example : during an Ice Age, for a drop of 30% in atmospheric Carbon Dioxide levels, the temperature of the tropical oceans dropped by 1 to 3 degrees C (and the reverse case, also) :-

“Carbon Dioxide Has Played Leading Role in Dictating Global Climate Patterns”, Agency: NSF, Date: June 17, 2010

A presentation by Schellnhuber at the 4 degrees and beyond conference last year made the case for treating the Pliocene as an analogue to current times :-

That’s certainly not 1 degree of warming, and that’s real, live historical data.

There are many questions (most of them unjustified) about the climate models, but there can surely be no arguing with history ? Or are the Climate Change sceptics all into revisionism ?



Joe Romm replies :-


Jo is right.

One can waste a lifetime trying to figure out what The “skeptics” aka the disinformers “believe.” Who knows and who really cares? The job of the media isn’t to explain what people who are wrong and/or are paid to lie believe or say they believe. The piece is bad — though there have been much worse recently.


Rich writes back :-


Whether it’s useful for journalists to present what skeptics believe is another matter. My point relates to the 1 degree issue. Harrabin isn’t referring to the paleoclimate, climate sensitivity or the models, he’s referring to “basic physics”, Wikipedia citing Rahmstorf:

“Without any feedbacks, a doubling of CO2 (which amounts to a forcing of 3.7 W/m2) would result in 1 degree C global warming, which is easy to calculate and is undisputed. The remaining uncertainty is due entirely to feedbacks in the system, namely, the water vapor feedback, the ice-albedo feedback, the cloud feedback, and the lapse rate feedback”

I agree that the language he uses is ambiguous, particularly the use of the word ‘consensus’, and I’ve emailed him about that. If you don’t like the piece, attack the fellow by all means, but arguing that he’s completely wrong on the 1 degree point won’t get you anywhere.



So, I replied again…


Hi Rich,

One of my problems is the use of the phrase “basic physics” itself. It sounds like a classic fudge from Patrick Michaels. What “basic physics” does Roger Harrabin possibly mean ? :-

“Most agree with the scientific consensus that basic physics means CO2 will warm the planet by about 1 degree C above pre-industrial levels.”

I don’t think you can safely assume that Roger Harrabin is making a reference to the actual science as quoted by Stefan Rahmstorf.

I think Roger Harrabin is making a reference to what he thinks is the “basic physics” as presented by Christopher Monckton :-

Roger Harrabin does not mention that the “one degree” would be in relation to a “doubling” of Carbon Dioxide. This is a critical omission.

Another problem is that even if he is talking about the radiative forcing of Carbon Dioxide he has not included other parts of the “basic physics”, as fleshed out in the Rahmstorf paper you refer to :-

Stefan Rahmstorf is not talking about highly speculative Climate Change effects – he is still talking about “basic physics”.

The fundamental “basic physics” includes things about which we are not entirely certain, but can give a range of probable values for. Therefore the use of the figure “about 1 degree C”, without giving a range from the full set of the “basic physics” is highly dubious.

I don’t like Roger Harrabin’s use of the term “scientific consensus”, because a casual reader would not know which part of the literature this refers to. The use of this term makes it an “us” type statement – usurping any opposition – as in “we think this – are you with us ?”, the kind of language used to shore up disastrous philosophies and regimes for centuries.

That means that the whole sentence is a fudge, and it seems to be intended to lodge in peoples’ minds. It would need a heap of qualifications in order to justify using it. Its purpose appears to be to leave a shard of falsehood in the public discourse.

Readers who have no inkling of what the sceptics get up to, and who have no in-depth exposure to the Climate Change science, could be left in error.

The sentence seems to be hinting at and reinforcing the “Global Warming is not that significant. Things will only change a little bit” argument of the sceptics.

It would be fine to use that sort of language amongst sceptic-kind, but please, not in the New Scientist magazine.

Language is so important. And in Climate Change, language is critical. We have to give a range of values if there is a range of values, and a range of probabilities if there is a range of probabilities. There is no room for shortcuts of the Roger Harrabin kind. He must know this, so I find it highly damaging that he has chosen the language he has.

I don’t think we needed to read what happened at the Heartland Institute sceptic conference in the New Scientist magazine. A huge waste of paper. The so-called sceptical position is actually unscientific, and based on conjecture and whim, including shaving values, warping research results, and denying the evidence.

Giving room for discussion of sceptic events is tantamount to offering support Climate Change scepticism – as there’s no such thing as bad news. For Roger Harrabin to write this article shows that he still doesn’t understand the problem with Climate Change scepticism, which is further evidence to corroborate the accusation levelled at him by some – that he is perhaps a Climate Change sceptic himself.

I don’t want to see articles like that again in New Scientist. One less page for non-science, one more page for proper science, in my view !

My finest regards,



3 replies on “Roger Harrabin : One Degree Is Not Enough”

Jo; Rich is right about climate senstivity.

Climate sensitivity for a doubling of CO2 is estimated at 2 – 4.5 degrees but that INCLUDES feedbacks.

The theoretical figure for climate senstivity without feedbacks can be worked out from basic physics and it is about one degree. In the real world this is physically impossible because you always get feedbacks, so 1 degree is not the real climate sensitivity, but it is what you would get in a fictional world in which the earth was just a lump of rock in space.

AR4 here, 3rd paragraph from the bottom:

And a much nicer explanation from Tamino:

There are various ways to estimate the real climate sensitivity. John Cook lists some of them here:

I agree that the New Scientist article is highly misleading because it suggests that computer models are the only evidence we have that the real climate sensitivity is higher than the sensitivity with no feedbacks. And that is garbage- there are many other lines of reasoning including plenty of direct empirical evidence, and – as you describe- paleodata.

However, IT IS completely correct to say that the theoretical construct “sensitivity with no feedbacks” is about one degree.

Best Wishes, Josie


The main question is this : what does Roger Harrabin mean by the “basic physics” ?

The feedbacks discussed in the first of your references are all what I could consider to be “basic physics” :-

“The diagnosis of global radiative feedbacks allows better understanding of the spread of equilibrium climate sensitivity estimates among current GCMs [General Circulation Model or Global Climate Model]. In the idealised situation that the climate response to a doubling of atmospheric CO2 [Carbon Dioxide] consisted of a uniform temperature change only, with no feedbacks operating (but allowing for the enhanced radiative cooling resulting from the temperature increase), the global warming from GCMs would be around 1.2 degrees C [Celsius] (Hansen et al., 1984; Bony et al., 2006). The water vapour feedback, operating alone on top of this, would at least double the response. The water vapour feedback is, however, closely related to the lapse rate feedback…, and the two combined result in a feedback parameter of approximately 1 Watt per metre squared per degree C, corresponding to an amplification of the basic temperature response by approximately 50%…”

By the way, this reference points to 1.2 degrees C, not “about 1 degree”.

This shows that Roger Harrabin has already rounded down the number.

The Climate Change sceptics have invented this trick argument that they don’t think they need to accept “the feedbacks”, confusing positive feedbacks such as land use change with the positive feedbacks of the basic physics such as water vapour increase.

This is a massive fudge. You can’t get Global Warming without getting these basic feedback responses. It is why Venus is hot and very cloudy and why the Earth is only warm and not so cloudy.

But that very paragraph that you are pointing to indicates a possible temperature rise of 2.4 – 3.6 degrees C or more, if I’m reading it right.

The very next paragraph says :-

“Using feedback parameters from Figure 8.14, it can be estimated that in the presence of water vapour, lapse rate and surface albedo feedbacks, but in the absence of cloud feedbacks, current GCMs would predict a climate sensitivity (within 1 standard deviation) of roughly 1.9 degrees C +/- 0.15 degrees C (ignoring spread from radiative forcing differences)…”

And that’s not 1 degree C either.


In the second link you give, of Tamino in his/her “Feedback” post, Tamino writes :-

Basic physics (the Clausius-Clapeyron equation) indicates that as temperature increases, the amount of wator vapor in the air should also increase….”

So Roger Harrabin should have included that in his figure for the Global Warming attributable to a doubling of Carbon Dioxide according to the “basic physics“. But he does not.

It’s because the Earth has an atmosphere that Roger Harrabin is in error, and he should admit to it.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.