UPDATE: Annan now suggests the IPCC “is in a bit of a pickle”, see below.
UPDATE2: Title has been changed to reflect Annan’s new essay, suggesting lying for political purposes inside the IPCC. Also added some updates about Aldrin et al and other notes for accuracy. See below.
Readers may recall there has been a bit of a hullabaloo at Andrew Revkin’s Dot Earth of the New York Times over the press release I first carried at WUWT, saying that I had “seized on it”.
Purveyors of climate doubt have seized on a news release from the Research Council of Norway with this provocative title: “Global warming less extreme than feared?”
I beg to differ with Andy’s characterization, as I simply repeated the press release verbatim without any embellishments. My only contribution was the title: Yet another study shows lower climate sensitivity. It turns out to the surprise of many that the subject of the press release was not peer reviewed, but based on previous cumulative work by the Norwegian Research Council. That revelation set Andy off again, in a good way with this: When Publicity Precedes Peer Review in Climate Science (Part One), and I followed up with this story demonstrating a lack of and a need for standards in climate science press releases by the worlds largest purveyor of Science PR, Eurekalert: Eurekalert’s lack of press release standards – a systemic problem with science and the media
It turns out that all of this discussion was tremendously fortuitous.
Surprisingly, although the press release was not about a new peer reviewed paper (Update: it appears to be a rehash and translation of a release about Aldrin et al from October), it has caused at least one scientist to consider it. Last night I was cc’d an exceptional email from Andrew Revkin forwarding an email (Update: Andy says of a comment from Dot Earth) quoting climate scientist James Annan, who one could call a member of the “hockey team” based on his strong past opinions related to AGW and paleoclimatology.
Andrew Revkin published the email today at the NYT Dot Earth blog as a comment in that thread, so now I am free to reproduce it here where I was not last night.
Below is the comment left by Andy, quoting Annan’s email, bolding added:
The climate scientist James Annan sent these thoughts by email:
‘Well, the press release is a bit strange, because it sounds like it is talking about the Aldrin et al paper which was published some time ago, to no great fanfare. I don’t know if they have a further update to that.
Anyway, there have now been several recent papers showing much the same – numerous factors including: the increase in positive forcing (CO2 and the recent work on black carbon), decrease in estimated negative forcing (aerosols), combined with the stubborn refusal of the planet to warm as had been predicted over the last decade, all makes a high climate sensitivity increasingly untenable. A value (slightly) under 2 is certainly looking a whole lot more plausible than anything above 4.5.’
And this is what many have been saying now and for some time, that the climate sensitivity has been overestimated. Kudos to Annan for realizing the likelihood of a lower climate sensitivity.
The leader of the “hockey team”, Dr. Michael Mann will likely pan it, but that’s “Mikey, he hates everything”. I do wonder though, if he’ll start calling James Annan a “denier” as he has done in other instances where some scientist suggests a lower climate sensitivity?
UPDATE: over at Annans’ blog, now there is this new essay expounding on the issue titled: A sensitive matter, and this paragraph in it caught my eye because it speaks to a recent “leak” done here at WUWT:
But the point stands, that the IPCC’s sensitivity estimate cannot readily be reconciled with forcing estimates and observational data. All the recent literature that approaches the question from this angle comes up with similar answers, including the papers I mentioned above. By failing to meet this problem head-on, the IPCC authors now find themselves in a bit of a pickle. I expect them to brazen it out, on the grounds that they are the experts and are quite capable of squaring the circle before breakfast if need be. But in doing so, they risk being seen as not so much summarising scientific progress, but obstructing it.
Readers may recall this now famous graph from the IPCC leak, animated and annotated by Dr. Ira Glickstein in this essay here:
Yes, the IPCC is “in a bit of a pickle” to say the least, since as Annan said in his comment/email to Revkin:
…combined with the stubborn refusal of the planet to warm as had been predicted over the last decade, all makes a high climate sensitivity increasingly untenable.
UPDATE 2: Annan also speaks about lying as a political motivator within the IPCC, I’ve repeated this extraordinary paragraph in full. Bold mine.
Note for the avoidance of any doubt I am not quoting directly from the unquotable IPCC draft, but only repeating my own comment on it. However, those who have read the second draft of Chapter 12 will realise why I previously said I thought the report was improved 🙂 Of course there is no guarantee as to what will remain in the final report, which for all the talk of extensive reviews, is not even seen by the proletariat, let alone opened to their comments, prior to its final publication. The paper I refer to as a “small private opinion poll” is of course the Zickfeld et al PNAS paper. The list of pollees in the Zickfeld paper are largely the self-same people responsible for the largely bogus analyses that I’ve criticised over recent years, and which even if they were valid then, are certainly outdated now. Interestingly, one of them stated quite openly in a meeting I attended a few years ago that he deliberately lied in these sort of elicitation exercises (i.e. exaggerating the probability of high sensitivity) in order to help motivate political action. Of course, there may be others who lie in the other direction, which is why it seems bizarre that the IPCC appeared to rely so heavily on this paper to justify their choice, rather than relying on published quantitative analyses of observational data. Since the IPCC can no longer defend their old analyses in any meaningful manner, it seems they have to resort to an unsupported “this is what we think, because we asked our pals”. It’s essentially the Lindzen strategy in reverse: having firmly wedded themselves to their politically convenient long tail of high values, their response to new evidence is little more than sticking their fingers in their ears and singing “la la la I can’t hear you”.
Oh dear oh dear oh dear…
Richard, you write “The truth of ‘global warming’ needs to be stated and those who deliberately misrepresent the truth need to be exposed.”
I agree completely, but there is an old saying, “Who is going to bell the cat?”. Somehow, someone or something needs to convince the Royal Society that you are right, and they need to come clean, and withdraw their support for CAGW. But what it will make this happen, I have no idea.
Matt G says:
You are still not calculating the no-feedback value of the climate sensitivity. If you are calculating anything real (and it is unclear to me if you are), what you are calculating is something akin to the sensitivity when the the lapse rate feedback (a negative feedback) included but none of the other feedbacks included. I have explained to you the correct way that the no-feedback value of the climate sensitivity is calculated.
Matt g says
Since the 1960′s CO2 levels have raised 80ppm until now so a doubling of CO2 won’t occur until it hits 630ppm. That means we are 25.4% of the target for a doubling of CO2. Therefore CO2 should have since the 1960′s only warmed the planet by 0.09c. The planet since then has risen 0.4c so only 25 percent at the most has come from CO2.
Therefore the Earth’s radiative physics not in a laboratory, shows the basic doubling of CO2 is 0.36c. This is how it should be when claiming a non feedback or not taking into account any feedback.
Henry@Matt/ Joeldshore
Sorry, Matt. Even that 0.36 is in doubt. Honestly. Even that estimate might still be too high. In fact, it could even still be that the effect of more CO2 is slightly negative or more like close to just zero.
According to my own results earth has indeed warmed about 0.45C since 1968. I am sure the 80 ppm on the CO2 increase you gave must be correct as well. We agree on that. However, I don’t know where that doubling up story came from, as if we are playing poker with the CO2. It is most surely not based on facts, i.e. actual tests and subsequent measurements. The facts are that there is both radiative warming and radiative cooling caused by the CO2. In fact, most recently they have also discovered absorbency of CO2 in the UV region, which is why we can measure it now on other planets (back radiation = cooling). On top of that we have cooling caused by CO2 due to the increase in greenery on earth:
more UV/warmth + (more)CO2 => (more) crops, more lawns, more trees, think of Las Vegas, Johannesburg etc.places that used to be deserts.
Nobody has produced a balance sheet to show me how much cooling and much warming is caused by the increase in CO2. I have explained the details here
http://blogs.24.com/henryp/2011/08/11/the-greenhouse-effect-and-the-principle-of-re-radiation-11-aug-2011/
so far, all my results seem to suggest that earth is following a natural path and that it is currently naturally cooling. My results also suggest it will continue cooling until about 2038.
http://blogs.24.com/henryp/2013/01/24/our-earth-is-cooling/
Don’t worry about the carbon. Better change your T-shirt now. Start worrying (a bit) about the cold. It won’t be long before everyone will start to notice….
I agree with Rocky Road that Joeldshore remarks were insulting to me and to the intelligence of skeptic thinkers at large..
Due to my own calcylations and analyses back in 1970’s, 1993 and last year, I second all but one thing – I doubt the cooling will end in 2038. Might be a short plus/minus zero but taking the position in the elips round the sun and other data due to wobbling, angle and such, my calculations points to 2072/73…. but of course I might be wrong.
Joel Shore please read RGB’s post at the following.
http://wattsupwiththat.com/2012/12/03/on-certainty-truth-is-the-daughter-of-time/
Please note his pointing out that the Holocene Max was 1.5-2 C higher than today. If we don’t know what caused that high a temperature without CO2 why do you assume CO2 is necessary to get us to a point lower than thousands of years ago. We cannot be sure the same mechanism working then is not working today.
By the way for the record RGB is a physics prof as are you. I would have said like you but that is rather not true.
I have asked you, Joel, several times to write a radiative heat transfer equation that shows how a colder atmosphere transfers heat to a warmer surface with the request that you show what the emissivity of CO2 is at 1 atm and 288K.
Jim Cripwell:
Thankyou for your post to me at February 3, 2013 at 7:30 am.
It says
I agree completely, but I don’t know either. Indeed, the problem is not only the RS.
Several national science institutions have been usurped by a small, unrepresentative clique of ‘green’ activists. Richard Lindzen details what has happened, who did it – he names names – and how they did it in a shocking paper which is a ‘good read’ and is at
http://www.lavoisier.com.au/articles/climate-policy/science-and-policy/LindzenClimatescience2008.pdf
There is another old saying; viz. ‘Possession is nine-tenths of the law’.
The usurpers have taken possession of the Executive Committees of the institutions.
It is one thing to know what has happened and another to correct it.
Richard
joeldshore;
That it is what “top of the atmosphere” means…It means that one is comparing all of the radiative flux coming into the atmosphere vs all leaving it.
>>>>>>>>>>>>>>>.
Oh.
My.
God.
Joel, the IPCC literature is very specific that their definition is at the tropopause, not at TOA. But put aside the fact that you seem unfamiliar with the IPCC literature itself and step back and look at your statement. Unless CO2 changes the amount of radiative flux absorbed in the first place, at equilibrium, the energy flux coming into and leaving the atmosphere are precisely the same. Double the amount of CO2 in the atmosphere and at equilibrium not only will the incoming flux and the outgoing flux be exactly equal to each other, they will be exactly equal to the previous values.
I presume you misstated your opinion in some way rather than raising the possibility that you earned a PhD in physics without understanding the very basics?
joeldshore;
My point is that in this case, there is no right or wrong answer for what sort of figure-of-merit best represents the change due to greenhouse gases. So, one ought to at least go with one that people have some intuition about.
>>>>>>>>>>>>>>>>.
Oh.
My.
God.
richardscourtney;
Our discussion regarding justification for averaging anomaly data has wandered across multiple threads. I’ve decided to expand my informal little survey. Do you have any objections to being listed as follows?
Zeke Hausfather; no response
Steven Mosher; no response
Joel D Shore; no single metric is right or wrong
******************
Robert G Brown; no justification
Richard S Courtney; no justification?
or would you prefer something slightly different? trying to keep it to just a few words (which was a bit of a challenge with Dr Shore)
joeldshore writes “I have explained to you the correct way that the no-feedback value of the climate sensitivity is calculated.”
Sorry, Joel, the no-feedback climate sensitivity cannot be measured, nor can it be calculated. It can only be estimated. There is a significant difference..
davidmhoffer:
re your question to me at February 3, 2013 at 8:58 am .
I absolutely, wholeheartedly and completely agree that there is no justification for using mean global temperature (MGT) as an indicator of climate change. Indeed, I am surprised that you bothered to ask when you know I have repeatedly linked to
http://www.publications.parliament.uk/pa/cm200910/cmselect/cmsctech/memo/climatedata/uc0102.htm
Appendix B of that item demonstrates that MGT is a misleading indicator of climate change. For example, its conclusions include
and
The latter paragraph of the latter quotation directly relates to your point concerning energy fluxes when it says,
“To treat the MGT as an indicative statistic has serious implications. The different teams each provide a data set termed mean global temperature, MGT. But if the teams are each monitoring different climate effects then each should provide a unique title for their data set that is indicative of what is being monitored.”
Richard
richardscourtney;
Indeed, I am surprised that you bothered to ask
>>>>>>>>>>>>>>>>>>
When stating the opinion of others, I always ask.
Richard, you write “I agree completely, but I don’t know either. Indeed, the problem is not only the RS.”
Yes, but if the RS changed, it would be a major triumph. I believe you live in the UK. You may have seen http://www.telegraph.co.uk/news/uknews/theroyalfamily/9844243/Duke-of-Edinburgh-invites-climate-change-heretic-David-Bellamy-to-Buckingham-Palace.html
It surely cannot be much more high profile than to have a first lecture in Buckingham Palace, with Prince Philip as a sponsor. Do you think that there is a chance that this might make a difference?
davidmhoffer:
I write to provide information as an addendum to my post addressed to you at February 3, 2013 at 9:19 am.
Some years ago I was a speaker at a Conference in Stockholm where Fred Singer, Bob Carter and Steve McIntyre were also speakers. One of the pro-AGW speakers was a representative of the Potsdam Insititute, and I challenged him to agree that MGT is not an appropriate indicator of climate change. He agreed and suggested that precipitation would be an appropriate indicator.
My question and the answer were in the questions following his presentation so are not on the public record, but I suspect those whom I have named would remember it.
Richard
All,
The question is (and it has varied from thread to thread):
Given that temperature anomalies have no linear relationship to temperature, is there any scientific justification for averaging and trending them in order to track the effects of CO2 and the global surface energy balance? As an example, an anomaly of 1 degree calculated from a baseline of -40 represents a change of 2.9 w/m2 while an anomaly of 1 degree from a baseline of +40 represents a change of 7.0 w/m2.
The informal results now stand as:
Zeke Hausfather; no response
Steven Mosher; no response
Joel D Shore; no single metric is right or wrong
******************
Robert G Brown; no justification
Richard S Courtney; no justification
Other people have expressed their opinion that there is no justification, but I can’t remember who for certain. If you’d like to be added to the list, please reply to that effect in this thread and I will add you in future threads. A statement of credentials would also be of value, if the list starts to get long I’ll probably want to add those. For now it is short enough that regular readers most likely know who each of those people are.
joeldshore says:
February 3, 2013 at 7:40 am
When calculating doubling of greenhouse effect from a simple black-body calculation and therefore using the Stefan–Boltzmann law is inaccurate. Black-bodies don’t take into account greenhouse gases and their behavior is different. Greenhouse gases are not proportional to temperature, whereas temperature is proportional to irradiance in a black-body. I agree this is supposed to be one of the better ways for estimating basic doubling, but it is still wrong.
If 150 w/m2 is the total background radiation then 3.7w/m2 must be no more than 2.5% of the total greenhouse energy. Using SB this gives a value which is higher than the percentage increase of the overall greenhouse effect. How is that even possible? Taking 2.5% of 33c is therefore only 0.81c of the greenhouse effect. The difference being CO2 is logarithmic so a additional 3.7w/m2 will have less effect than 0.81c for a doubling CO2 on average. The SB law doesn’t take this into account and can’t calculate how much of a increasing greenhouse gas component contributes to the overall greenhouse effect.
HenryP says:
February 3, 2013 at 7:53 am
The 0.36c value using more recent updated observed back-radiation satellite data actually declines further. I agree it likely is a value lower than this using this data because the value represents the basic highest one possible. Note – I did mention this below in my post also and neither of these were taken into account with this value.
“This is being generous because most of the warming from greenhouse gases occurs during the first parts with it being logarithmic. This also doesn’t take a water body into account either on the surface.”
[However, I don’t know where that doubling up story came from,]
There is more about this in my previous post.
Jim Cripwell:
At February 3, 2013 at 9:26 am you write to me
Firstly, I need to declare two personal interests.
I know David Bellamy because he and I have shared platforms at speaking engagements on a couple of occasions. He is a celebrity: I am not. Hence, although I can provide him with support, there is no possibility that I could have anywhere near as much effect as him. People will listen to him but only wonder who I am.
I am a Member of the RS having been appointed to the Association of British Science Writers by the British association for the Advancement of Science, so I have access to the RS Library etc. (which is why e.g. I was able to obtain documents from the RS archives for the late John Daly in his ‘Isle Of The Dead’ study). However, I am NOT an RS Fellow so I cannot interact with or affect the RS organisation in any way.
Hence, I don’t think I can do anything to publicise the meeting of David Bellamy with HRH or to get the publicity to affect the RS. But I will ask Bellamy if there is anything I can do to help in these matters if that is his desire. Other than that, I don’t know what I can do.
Richard
Matt G;
You’ve got a whole lot of different issues all tangled up with each other. The SB Law formula is:
P=5.67*10^-8*T^4
P is in w/m2
T is in degrees K (degrees C+273)
Noting that P and T do not vary linearly with each other, let’s go through your statements:
If 150 w/m2 is the total background radiation then 3.7w/m2 must be no more than 2.5% of the total greenhouse energy.
150 w/m2 is not the background radiation, it is an approximation of the ghe. There is no such thing as “greenhouse energy” , there is such a thing as the “energy flux” measured in w/m2. Lastly, since the relationship between P and T is not linear, calculating a % of anything is applying a linear calculation to a non-linear system.
Using SB this gives a value which is higher than the percentage increase of the overall greenhouse effect. How is that even possible?
Apply the formula to any given temperature and any given energy flux and you will get the right results.
Taking 2.5% of 33c is therefore only 0.81c of the greenhouse effect
Again, you are applying a linear calculation to a non-linear function.
The difference being CO2 is logarithmic so a additional 3.7w/m2 will have less effect than 0.81c for a doubling CO2 on average.
That’s not what being logarithmic means. It means that doubling of CO2 from any given starting point results in 3.7 w/m2. So, if we are currently at 400 ppm, getting another 3.7 w/m2 would require +400 ppm. But at 800 ppm, it would require +800 ppm to get that same 3.7 w/m2.
The SB law doesn’t take this into account and can’t calculate how much of a increasing greenhouse gas component contributes to the overall greenhouse effect.
Well it does if you apply it correctly. That said, calculating an average T for earth surface and an average P for ghe is a fool’s errand, so there’s no easy way to apply SB Law.
Matt G says
[However, I don’t know where that doubling up story came from,]
There is more about this in my previous post.
Henry says
Don’t worry. I know it (i.e. the doubling story) is rubbish anyway.
You cannot “calculate” that which has never been measured first.
richardscourtney says:
The correct answer is closest to (b). How could I possibly know unless I have actually investigated it, as others such as NOAA have? And, alas, they did not present their results in the way that you want (in terms of the length that the 95%…or whatever…confidence interval of the measured trend includes a trend of zero) because, at best, this would be a very indirect way of looking for incompatibility between the models and the observed trend.
My point is that it takes 12-14 years for the trend to be statistically-significant even if the trend is EXACTLY what is expected by the models. Do you really believe that just a few more years would then lead to a complete incompatibility with the models? That would be truly bizarre.
As for the larger point of the complete untenability of your interpretation of the NOAA statement, I will simply summarize the points I made before in that other thread:
(1) The NOAA statement reads: “The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more…” The authors chose to put the parenthetical expression after “rule out” rather than after “zero trends”. Why would they do this if they wanted it to modify “zero trends”? I could actually see the reverse happening, i.e., I could see them writing “The simulations rule out zero trends (at the 95% level)” when they really meant it to modify “rule out”…This would be a little sloppy, but certaintly reads more naturally than sticking the parenthetical expression in the middle. The fact that the authors explicitly avoided that more natural-sounding construction is clearly because they wanted to make it clear that the parenthetical expression modifies “rule out” and not “zero trends”.
(2) If you adopt my interpretation, there is no real ambiguity in the statement. We know what is meant by “rule out” and we don’t have to worry about questions of how one determines the uncertainty in the trend estimate on the empirical data (i.e., what model one uses for the correlations known to exact in the data) because no such estimate is required. With your and Monckton’s interpretation, we don’t know what “ruled out” means (to what level of certainty?) and we don’t know what sort of model to use for the correlations in the empirical data in order to arrive at an uncertainty estimate for the trend.
(3) With my interpretation, there is a straightforward way to explain how they came to the conclusion that they did based on what they discuss regarding the simulations that they performed using the climate models: They looked at all the independent periods of a certain length in these multiple simulations and found that one had to make the length 15 years long in order that fewer than 5% of the simulations had trends less than zero. That is what it means to rule out at the 95% confidence level a zero trend. With your and Monckton’s interpretation, it is not clear what they did. How did they get from their simulations to their conclusion? You have never explained this because you can’t.
(4) As I noted previously, the SkepticalScience trend calculator (the only one that I know of that is available online) shows 15-year trends of temperature data to have an uncertainty of about 0.14 C per decade. That means that the “borderline” case of a trend that would not rule out a zero trend at 95% confidence is a trend of 0.14 C per decade, which would be compatible with the underlying trend lying anywhere between 0 and 0.28 C per decade with 95% confidence. Does it really make sense whatsoever that the models, which predict trends on average of about 0.20 C per decade would rule out an empirical trend whose 95% confidence interval goes from 0 and 0.28 C per decade? That is patently absurd!
(5) Furthermore, the entire context of their discussion is that they are looking at ENSO-adjusted data, where the adjustment procedure is discussed in a paper that they reference. Such a procedure is necessary in order to increase the signal-to-noise ratio enough to even be able to come to the conclusion they have about 15 year trends. I
In response, the only real argument that you have been able to come up in response is a claim that to talk about ruling something out at a 95% confidence level is oxymoronic. However, you have been shown that it is in fact rather common practice to talk in such terms when discussing statistical data analysis, as this example from the entirely unrelated field of high energy physics shows:
Inger E says
Due to my own calcylations and analyses back in 1970′s, 1993 and last year, I second all but one thing – I doubt the cooling will end in 2038. Might be a short plus/minus zero but taking the position in the elips round the sun and other data due to wobbling, angle and such, my calculations points to 2072/73…. but of course I might be wrong.
Henry says
My original results
http://blogs.24.com/henryp/2012/04/23/global-cooling-is-here/
initially led me to believe in a (natural) binomial for the speed of warming versus time (degreesK/yr2),
at least for the period measured, i.e 1974-2012
but eventually I agreed with those commenting that it must be an A-C wave, like this,
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
it is this fit that suggests the 2038 as the date when cooling turns back to warming again.
However, Inger, I am always interested in seeing other people’s evaluations of actual data,
so I am very curious – and indeed most interested! – as to how you came to the 2072 date?
Sorry if my English isn’t the best at almost 5 in the morning. (I read 9 languages, speak 6 but I have problems with grammar in every one of them. Partly dyslectic while writing)
Given that everything is energy, and energy never ceases to exist, but only changes form, I looked at the changes in the in-and outflow of energy since
Stone Age. The period up to the year 1000, I analyzed 1992 to put “meat” on the bones re. understanding the sea-level changes there been during the period.
ie changes within and between different time periods. Premisses needed to complete the changes in waterlevels using Archimedes principle on impact from melting ice including the landrise effect.
While looking at the later period 1000 AD (or if you so want 1000 BP) up almost to now all changes in Earth temperature, Ice Ages including peaks and such can be explained only using the Natural forces. In other words the Physical laws as we know them. But there is one difference to be observed. That is the period after we humans started to use aerosoler effecting the Ozone layer. At first the ‘hole’ got wider and then after global forbidding of usage they are growing towards ‘normal’.
If one look at the anual average total ozon trend 1979 to 2000 Chapter 12: Modeling, Assessments, and Trend Prediction; ccpo.odu.edu it’s possible to see the quick recovery after UN decided re. Regulation on substances that deplete the ozone layer.
Back to basic. If everything is energy which only change form, and we are discussing the form of inflow and outflow of energy from Earth one has to consider the effect of the “Ozonhole” as a new factor taking into consideration while analysing the total effect. Not only from the point of view that the ‘hole’ extended the inflow, but also where to look for changes in the outflow of energy not taken into consideration using ‘ordinary’ calculations. Since the changes of Ozon in Stratosphere were seen over the poles I in my analyse taken that into consideration. The only assumtion I have made is that we are in the second phase of a longer global cooling broken by for example Atombombs and for example aerosols ‘hurting’ the Ozon layer. If one look at the image that is one of a very few possible conclusions to be drawn.
Thus when looking at the ‘healing’ of the Ozon holes I taken into consideration the possibility of changes in the outflow over same period. That is where the angle and vobbling comes in. But of course I can be wrong in my calculations re. cooling period to come.
davidmhoffer says:
We are not talking about what happens once one is back in equilibrium. Here is the sequence of events after an imagined instantaneous doubling of CO2:
(1) The amount of radiative forcing is a little over 4 W/m^2. In other words, 4 W/m^2 more are being absorbed by the Earth than emitted.
(2) The stratosphere undergoes relatively rapid adjustment and this imbalance drops a bit to about 3.7 W/m^2. You are correct that for technical reasons, the IPCC chooses to use this “tropopause” value rather than the original value.
(3) Over time (and it takes quite a bit of time!), the temperature rises due to the radiative imbalance until such time as the Earth is again emitting as much as it is absorbing.
That is a reasonable summary in 10 words or less of what my major point is.
Jim Cripwell says:
I will not disagree with you. What you call the “no-feedback” case does have a certain amount of arbitrariness to it. So, maybe a better way to put it is that for the way that climate science has chosen to define the no-feedback case, my discussion explains the correct way to calculate it.
davidmhoffer says:
February 3, 2013 at 10:22 am
The two paragraphs are separate calculations and issues. (I did mean energy flux.)
The 150 w/m2 was a made up value I used to demonstrate this point. The actual values I have already posted were 324w/m2 and 333 w/m2 for back-ground radiation. This value was never used with SB so not using linear and non-linear calculation together here.
[Taking 2.5% of 33c is therefore only 0.81c of the greenhouse effect
“Again, you are applying a linear calculation to a non-linear function.”
The difference being CO2 is logarithmic so a additional 3.7w/m2 will have less effect than 0.81c for a doubling CO2 on average.]
I agree with applying a linear calculation to a non-linear function here, but it still gives a good estimate. No where near as bad as using SB for doubling of CO2 calculation.
In previous posts covering this topic I have mentioned the logarithmic function before correctly. I have muddle this sentence up and sorry for the confusion.This is what happens sometimes when you rush posts and of course meant there is less effect with an additional 3.7w/m2 because it requires a continuous doubling of CO2 from the previous 3.7w/m2.
“The SB law doesn’t take this into account and can’t calculate how much of a increasing greenhouse gas component contributes to the overall greenhouse effect.”
[Well it does if you apply it correctly. That said, calculating an average T for earth surface and an average P for ghe is a fool’s errand, so there’s no easy way to apply SB Law.]
Using SB the temperature is 279k that a black-body would have, the Earth’s temperature already been shown is about 288k.
Matt G;
Sorry, but you still have multiple issues confused. SB has nothing to do, nothing at all, with calculating the change in w/m2 of doubling of CO2. You arrive at a value for doubling of CO2 in w/m2 first and then as a second step you can calculate the change in T for a given change in w/m2.
You’ve also got the SB temperature of the planet wrong, it is 253K, not 279.
You’ve also misunderstood the reference frame. As seen from space, the temperature of the planet is indeed 253K, a match to SB Law. This is called the effective black body temperature of earth. As seen from space however, we are not seeing a surface. We’re seeing escaping energy flux that may have been radiated from earth surface, from TOA, or anywhere in between. At about 14 km altitude, temps are indeed about 253K. Above, they are colder. Below, they are warmer. (that’s a generalization). At earth surface, they are 33K warmer. The effective average (if you will) from surface to TOA is in fact 253K.
When CO2 doubles, the effective black body temperature of earth stays precisely the same, 253K. What changes (in theory) is the average height at which the effective black body temperature occurs, with temps above being cooler and temps below being higher.
Now I have certain reservations about the theory, and the feedbacks, but discussion of the ghe and any effective criticism of the theory must start with a sound understanding of the theory itself. I suggest you spend some time with first year physics texts. I think Robert G Brown mentioned he has published same on the internet for free.