Guest commentary by Kevin Trenberth and John Fasullo
The hype surrounding a new paper by Roy Spencer and Danny Braswell is impressive (see for instance Fox News); unfortunately the paper itself is not. News releases and blogs on climate denier web sites have publicized the claim from the paper’s news release that “Climate models get energy balance wrong, make too hot forecasts of global warming”. The paper has been published in a journal called Remote sensing which is a fine journal for geographers, but it does not deal with atmospheric and climate science, and it is evident that this paper did not get an adequate peer review. It should not have been published.
The paper’s title “On the Misdiagnosis of Surface Temperature Feedbacks from Variations in Earth’s Radiant Energy Balance” is provocative and should have raised red flags with the editors. The basic material in the paper has very basic shortcomings because no statistical significance of results, error bars or uncertainties are given either in the figures or discussed in the text. Moreover the description of methods of what was done is not sufficient to be able to replicate results. As a first step, some quick checks have been made to see whether results can be replicated and we find some points of contention.
The basic observational result seems to be similar to what we can produce but use of slightly different datasets, such as the EBAF CERES dataset, changes the results to be somewhat less in magnitude. And some parts of the results do appear to be significant. So are they replicated in climate models? Spencer and Braswell say no, but this is where attempts to replicate their results require clarification. In contrast, some model results do appear to fall well within the range of uncertainties of the observations. How can that be? For one, the observations cover a 10 year period. The models cover a hundred year period for the 20th century. The latter were detrended by Spencer but for the 20th century that should not be necessary. One could and perhaps should treat the 100 years as 10 sets of 10 years and see whether the observations match any of the ten year periods, but instead what appears to have been done is to use only the one hundred year set by itself. We have done exactly this and the result is in the Figure..
[ed. note: italics below replace the deleted sentence above, to make it clearer what is meant here.]
SB11 appears to have used the full 100 year record to evaluate the models, but this provides no indication of the robustness of their derived relationships. Here instead, we have considered each decade of the 20th century individually and quantified the inter-decadal variability to derive the Figure below. What this figure shows is the results for the observations, as in Spencer and Braswell, using the EBAF dataset (in black). Then we show results from 2 different models, one which does not replicate ENSO well (top) and one which does (second panel). Here we give the average result (red curve) for all 10 decades, plus the range of results that reflects the variations from one decade to the next. The MPI-Echam5 model replicates the observations very well. When all model results from CMIP3 are included, the bottom panel results, showing the red curve not too dis-similar from Spencer and Braswell, but with a huge range, due both to the spread among models, and also the spread due to decadal variability.
Figure: Lagged regression analysis for the Top-of-the-atmosphere Net Radiation against surface temperature. The CERES data is in black (as in SB11), and the individual models in each panel are in red. The dashed lines are the span of the regressions for specific 10 year periods in the model (so that the variance is comparable to the 10 years of the CERES data). The three panels show results for a) a model with poor ENSO variability, b) a model with reasonable ENSO variability, and c) all models.
Consequently, our results suggest that there are good models and some not so good, but rather than stratifying them by climate sensitivity, one should, in this case, stratify them by ability to simulate ENSO. In the Figure, the model that replicates the observations better has high sensitivity while the other has low sensitivity. The net result is that the models agree within reasonable bounds with the observations.
To help interpret the results, Spencer uses a simple model. But the simple model used by Spencer is too simple (Einstein says that things should be made as simple as possible but not simpler): well this has gone way beyond being too simple (see for instance this post by Barry Bickmore). The model has no realistic ocean, no El Niño, and no hydrological cycle, and it was tuned to give the result it gave. Most of what goes on in the real world of significance that causes the relationship in the paper is ENSO. We have already rebutted Lindzen’s work on exactly this point. The clouds respond to ENSO, not the other way round [see: Trenberth, K. E., J. T. Fasullo, C. O’Dell, and T. Wong, 2010: Relationships between tropical sea surface temperatures and top-of-atmosphere radiation. Geophys. Res. Lett., 37, L03702, doi:10.1029/2009GL042314.] During ENSO there is a major uptake of heat by the ocean during the La Niña phase and the heat is moved around and stored in the ocean in the tropical western Pacific, setting the stage for the next El Niño, as which point it is redistributed across the tropical Pacific. The ocean cools as the atmosphere responds with characteristic El Niño weather patterns forced from the region that influence weather patterns world wide. Ocean dynamics play a major role in moving heat around, and atmosphere-ocean interaction is a key to the ENSO cycle. None of those processes are included in the Spencer model.
Even so, the Spencer interpretation has no merit. The interannual global temperature variations were not radiatively forced, as claimed for the 2000s, and therefore cannot be used to say anything about climate sensitivity. Clouds are not a forcing of the climate system (except for the small portion related to human related aerosol effects, which have a small effect on clouds). Clouds mainly occur because of weather systems (e.g., warm air rises and produces convection, and so on); they do not cause the weather systems. Clouds may provide feedbacks on the weather systems. Spencer has made this error of confounding forcing and feedback before and it leads to a misinterpretation of his results.
The bottom line is that there is NO merit whatsoever in this paper. It turns out that Spencer and Braswell have an almost perfect title for their paper: “the misdiagnosis of surface temperature feedbacks from variations in the Earth’s Radiant Energy Balance” (leaving out the “On”).
Glad to see you post on this study. We fired off a story on this last night, after the Forbes column was highlighted on Drudge. According to Mike Lemonick, who wrote the Climate Central piece, it seemed to be a case where a study was saying 1 thing, and the author was saying/writing another to the press, inspiring all sorts of online shenanigans. http://www.climatecentral.org/blogs/global-warming-debunked-or-not/
Best,
-Andrew
“The paper’s title “On the Misdiagnosis of Surface Temperature Feedbacks from Variations in Earth’s Radiant Energy Balance” is provocative and should have raised red flags with the editors.”
Hmm. On the cynical side, one wonders if the editors published this article because of the provocative title and content. Remote Sensing is not listed on Web of Science; one wonders if they’re trying to increase their visibility with the old adage, “there’s no such thing as bad publicity…”
> visibility
The fee is 500 Swiss Francs to publish:
http://www.mdpi.com/about/apc#amount-apc
and, a bit outdated, that page says
“currently planning for the implementation of a discount system for peer-reviewers that kindly offered their services to our journals. This new discount system will be in place in middle of 2010”
> the editors
There may be an opportunity for someone:
Open positions at MDPI
Assistant Editor
Posted: 1 February 2011
Location: Office in Haidian, Beijing, China
Contact: kelly.chen@mdpi.com
Andrew Dessler seems to have summed the goal of this publication up well in a comment published on Climate Progress:
“[This] paper is not really intended for other scientists, since they do not take [Roy Spencer] seriously anymore (he’s been wrong too many times). Rather, he’s writing his papers for Fox News, the editorial board of the Wall St. Journal, Congressional staffers, and the blogs. These are his audience and the people for whom this research is actually useful — in stopping policies to reduce GHG emissions — which is what Roy wants.”
http://thinkprogress.org/romm/2011/07/29/282584/climate-scienists-debunk-latest-bunk-by-denier-roy-spencer/#more-282584
“Spencer has made this error of confounding forcing and feedback before and it leads to a misinterpretation of his results”.
If CauseA initially produces EffectB = CauseB which then produces EffectC, is EffectC the result of a Forcing (CauseB) or a Feedback (EffectB)?
Methinks we need some rigorous definitions of Forcing and Feedback.
Just to be a contrarian here: Despite your superb dissection, the paper was wildly successful. And it has nothing to do with it’s scientific worth. This was another PR assault masquerading as a serious science paper.
It garnered terrific publicity in Fox, Forbes and other Murdoch outlets. It further stoked the emotional embers of confusion and doubt in the public. Politicians and climate policy wonks can wield and wave this one.
People are getting assaulted by heat waves, droughts and floods. It succeeded wonderfully in distracting attention and feeding the hunger for pseudo validation of magical thinking. Some will fiercely refuse to accept anthropogenic climate change – no matter what the evidence or science.
It managed to suck up your time in evaluating the data and methodology and authoring this response but I must thank you so much for doing some excellent analysis, and for correcting this paper. You have turned this into a teaching opportunity. Something that is endless.
There will be more efforts like this – this was too easy. The slight downside of writing a bad science paper is a trivial cost for such a PR success.
The current tally for Google citations for the title is 3,3800
http://bit.ly/p8pKyN
I think the comment from Andrew Dessler (quoted above by Chris McGrath).
This publication is “Ditto-Head Science”. It is not intended as a serious contribution to climate science. It is merely fodder for the deniers, who will for the most part not even look at Spencer’s paper itself, but will simply run around the Internet bellowing that anthropogenic global warming has been “refuted”, and trying to prove that they can shout “alarmist” more times than the Heartland Institute’s propagandist Taylor did in his ludicrous “news article”.
Has anybody given my critique of the paper any thought?
https://www.realclimate.org/?comments_popup=8345#comment-211747
His feedback loop only gives lower results if and only if he selects any period other than -λT, his conclusion is clearly off and maybe his model as well if not done correctly..
[Response: I’m not sure I follow you. The regressions he is doing are on the deseasonalized monthly anomalies – there is no selection there. – gavin]
Well, here’s one blogger not taken in by Taylor.
[Response: This is going too far. I doubt the editors of Remote Sensing are guilty of anything more than poor choice of peer reviewers. The problem with the paper is that it is just poor, not fraudulent – though the overheated commentary in the blogosphere clearly crosses the line into misrepresentation. People are too eager to toss around extremely strong language that does the discourse no good at all. – gavin]
More about Spencer:
http://bartonpaullevenson.com/Spencer.html
A little more on Spencer:
http://bartonpaullevenson.com/Spencer.html
About RS:
http://bartonpaullevenson.com/Spencer.html
@ Richard Pauli
Have you read the blogs in your Google list, though? Even the moms at Cafe Mom rip into Spencer’s paper, beginning with…
Guess the rest.
simon abingdon @ 5 Methinks we need some rigorous definitions of Forcing and Feedback.
Hey! I’ll bet climatologists never thought of that! Write a paper. You’ll get hundreds of citations.
#13 J Bowers…right you are. However a PR success is not measured by the sides of an argument… it is measured by putting the issue in front of the audience. Success is by how many people see the controversy continue. The promotion is for the very idea of dispute. Logic is irrelevant to a PR campaign. A wrong paper creates a bigger controversy – and more buzz – than a correct one.
Pity.
Someone at NASA needs to check a few links; searching on the authors of that paper comes up prominently with links leading to this page:
http://spacescience.spaceref.com/newhome/headlines/essd12mar97_1.htm
“Despite the fact that Hurrell and Trenberth _estimate_ of the temperature of the atmosphere through a simple linear regression model based only on the sea surface temperatures, and a global climate model simulation with the same sea surface temperatures but no stratospheric volcanic aerosols, while the MSU data actually _measure_ the temperature of the free atmosphere, Hurrell and Trenberth conclude that the satellite data must be wrong….”
—–
and that page links to this page:
http://spacescience.spaceref.com/newhome/essd/atmosphere_today.htm#anchor547043
“Maps of Global atmospheric temperatures are available …. All data are available in global or continental U.S. projections. Interactive access for selection of daily temperature data is available.”
And still no one can explain why incremental GHG ‘forcing’ will be amplified by over 400% when solar forcing is only amplified by about 60%. I think the peer review process is broken, but the nonsense continues on.
[Response: Where do you get that from? Climate sensitivity is pretty close to equivalent for most forcings. – gavin]
Gavin,
The ‘direct’ warming from 3.7 W/m^2 is about 0.7 C from the S-B law. The additional 0.4-0.5 C to get the often referenced 1.1-1.2 C of ‘intrinsic’ warming from 2xCO2 comes from adding on net transmittance to space of about 62% (0.7 C x 0.62 = 0.43). Net transmittance to space (aka the planet’s ‘effective’ emissivity) is directly derived from the system’s response to solar forcing (240/390 = 0.615), whose inverse of 1.63 W/m^2 is the amount of radiative surface flux required to allow 1 W/m^2 to leave the system (1/0.615 = 1.63; 1.63 x 240 = 390).
0.43C/0.7C = 0.62 (62%); 3.0C/0.7C = 4.29 (429%).
If you really think +3.7 W/m^2 from 2xCO2 is going to become +16.6 W/m^2 required for a 3 C rise, you should explain why it doesn’t take 1077 W/m^2 of surface power to offset the 240 W/m^2 of incident solar power (16.6/3.7)*240 = 1077.
[Response: You are confusing surface energy balance with the response to a TOA/tropopause forcing. Similarly, you are thinking that the Earth’s greenhouse effect can be modelled purely as an effective emissivity (i.e. ‘grey’ body). This does not actually fit the reality of why the surface temperature responds to the greenhouse effect since the emissivity itself is not independent of temperatures and greenhouse absorbers. Read Ray’s Climate Book for a more thorough treatment. – gavin]
re: #9
Yes, people *really* need to be careful to not say academic fraud, just for bad paper.
Plagiarism is academic fraud, and once found, is easy to show. Falsification/fabrication is harder, especially as it takes more expertise to explain convincingly to a larger audience. See the first page of the PDF here for commentary on the differences, and then some examples that go beyond plagiarism.
Lest we forget, this paper made its public debut four years ago as Roy’s after dinner speech at the 1st Heartland conference. He said at the time it had been submitted for peer review (JGR, IIRC) the year before!
“but instead what appears to have been done is to use only the one hundred year set by itself.
Did you mean:
“but instead what appears to have been done is to use only the one ten year set by itself.”?
From:
http://www.climatecentral.org/blogs/global-warming-debunked-or-not/
“Spencer……says that changes in cloud cover are a major cause of climate change.”
Is obviously nonsense because that would lead to a very unstable climate.
Could you go over how you make an “Inter-Decadal Span of Regression” please? I get that you are making a graph of the lead and lag in the timing of the ENSO and then doing statistics on it. I don’t think I took that statistics course yet.
Well, Gavin, what RW says is perfectly correct: no one can explain why GHGs are forced 7 times as much as solar. Of course, no one tries to explain it because no one believes it, but maybe RW isn’t in on that part of the joke ;)
Drs. Trenberth and Fasullo,
Many thanks for the prompt and devastating refutation of Spencer’s latest example of bad sicence. Sorry that you have to waste your valuable time dealing with such BS.
I agree with Richard Pauli’s post at #6.
Spencer has already won his PR victory, and the job of this paper is done. The biases in the vast morass of the collective denialist mind have been confirmed, and inaction has been cemented for yet another critical period – and these days critical periods are able to be measured in months rather than years.
Corrections such as this one of Kevin’s and John’s, and of others such as Barry Bickmore’s, are of course very necessary – but I think that the best answer to Spencer’s shitting in the pool of scientific understanding is to either publish a peer-reviewed rebuttal, or to move for a withdrawal of Spencer’s paper itself. Or both. Less than that, and the appropriate scientific response will not reach the general public, where the damage has been done in the first place.
(ReCaptcha says “dentis subalgebra”…!?)
> where do you get that from
William Connolley asked for cites for his numbers, repeatedly: http://scienceblogs.com/stoat/2011/06/lindzen_goes_emeritus.php#comment-4227967 — he also posted the claim at Spencer’s and was ignored, and also a couple of times at site:skepticalscience.com “amplified by over 400%”
As an aside, I noted a significant error in the first sentence of the Fox News article, documented here:
I’m not saying Fox News is stupid, but…
It sure did make me chuckle. Editing is more than just spelchecking! Consider this my “peer review” of Fox News.
Thanks for posting a substantive criticism which does not engage in ad hominem or poisoning the well. I have been looking for a post which criticizes the study which does not also engage in fallacious rhetoric, and yours is the first I have found.
Re: Prof Schmidt’s response to #9: wise words indeed – perhaps there is nothing more sinister than confirmation bias going on. What is your opinion of recent developments in the UK? It concerns me that “regulation” of peer review has a very real potential to have a chilling effect on research, and certainly of outlying views, in exchange for limited benefits if any at all. Fraud will be extremely difficult to prove, but easy to allege, and you don’t have to be a climate scientist to figure out where most of these allegations will be coming from. It seems to me that this will provide another weapon for the Cuccinellis of this world to harass researchers, and yet it will not prevent papers such as Spencer and Braswell being published (assuming such prevention is desirable).
#14 Pete Dunkelberg
So what are the definitions of Forcing and Feedback? How are they to be unambiguously distinguished? I think I might reasonably claim that the Sun is the only real Forcing and that all climatic effects are consequent Feedbacks.
Further to my earlier post: If you want to study the behaviour of a “system” you might start by defining its boundaries. Then any external influence is a Forcing on that system while its internal behaviours are the Feedbacks resulting from that external Forcing. The choice of the “system” is arbitrary, in the sense that it’s whatever you choose to study. So one man’s Feedback is another man’s Forcing. To say that Spencer confounds the two looks to me unreasonably dismissive.
[Response: I agree that the boundaries of a modelled system define what is forcing (external) and what is feedback (internal), but Spencer’s idea of ‘internal radiative forcing’ is nonsense even by your definition. Furthermore, the system we are talking about almost exclusively is already well-defined, and so there isn’t that much ambiguity. Only if you have a forcing that specifically affects clouds by means of some aspect of their physics that is already within the system will you have a specific forcing from clouds (in this sense). For instance, indirect aerosol effects (via increased SO2 pollution, or cosmic ray modulation of ionisation) count as forcings, but the response of clouds to dynamical changes, circulation, temperature or humidity do not. – gavin]
The arguments are incomprehensible for a naive Sustainable Development scientist, like me and therefore useless for a debate with me at least. Either one believes one side or the other.
But one of the comments No. 6, Pauli, deserves special attention, me thinks. It says the scientifc quality is unimportant. It’s the PR and confusion generated that counts.
That’s why the speech of Mr Achim Steiner, head of UNEP at the UN Security Council, some ten days ago is so utterly stupid and a waste of time. (Link to Steiner’s speech:
http://www.unmultimedia.org/tv/webcast/2011/07/achim-steiner-unep-security-council-meeting-part-1.html )
The whole flipping climate debate is one huge distraction from the underlying I=PAT.
Human Impact on the planet
equals
Population size times Affluence (standard of living) times Technology.
The very same IPCC is beset by people who believe the market and technology will provide solutions, whereas growth is no issue.
Earlier this year a main author of the IPCC’s 4th report said in a public presentation at the Geneva Graduate Institute that we’ve lost the battle against GreenHouseGas emissions. (cf.
http://www.wachstumsforum.ch/climate/e/index.htm )
Yet he does not call for a growth stop, he said, obviously suffering from the same omnipresent growth virus.
This Climate Craze does not influence the bureaucrates at the WTO, ICTSD et al. They’re functioning because a job is a job is a job.
My next trip is to Korea, the country that’s on it’s Green Growth trajectory, for a series of talks to explain why Aid for Trade is good
for hungry Africans and will help stopping Climate Change and resource
depletion.
Yours climatolocrazically … Helmut
PS: Did anybody enroll for the next WTO public Forum, in September?
Try to tell Mr Lamy that the temperature predictions have been debated and how important that is for the success of the DOHA round.
My view of climate is basically similar to Trenberth and Fasullo’s. But I do not think their words “Clouds … they do not cause the weather systems” are adequate in the tropics. Tropical weather systems are driven by cumulus cloud convection, and what we see as weather systems are their collective behavior. They are modulated, of course, by the planetary-scale circulations, land-sea contrast and sea surface temperature anomalies. But they do not seem fully determined by large-scale forcing, but they seem considerably stochastic or chaotic.
Clouds respond to radiative forcing and feed back to large-scale climatic states. But that is not straightforward. Radiative forcing has, first, day-night contrast, and second, land-sea contrast. Forcing due to climate change comes as modulation to these complex spatio-temporal structure. So what we can do is to try partial understanding our based on either statistical analyses or simplified models.
richard pauli — “However a PR success is not measured by the sides of an argument… it is measured by putting the issue in front of the audience.”
I think that’s oversimplistic, and the method can also backfire. People do click on the links. The difference with this paper is that it isn’t being splashed all over the web in general comments as usual, that I can see. Sure, FOX will run with it, and Forbes, but up would be down if they didn’t. It just ain’t cropping up as proof of “a scam” everywhere else. It’s actually a bit weird.
And sorry, perhaps I shouldn’t have quoted in #9. Harsh words, though. Harsher than you’ll usually find.
“vast morass of the collective denialist mind. . .”
Surely it’s only half vast?
A feedback is just a response to a forcing. If that response causes a further effect, it becomes a new forcing. Feedbacks by themselves are merely passive; only when they become forcings do they cause changes. So there’s your definition: forcings cause changes, feedbacks as such do not, until or unless they become forcings, when their erstwhile feedback status is no more than interesting history.
[Response: This definition makes no sense at all. The whole point of a forcing/feedback analysis is to be able to predict the response of the system to external perturbations. We are interested in the internal responses to those perturbations that then cause further perturbations (i.e. water vapour response to temperature which then further affects temperature via the greenhouse effect). If we define them away as forcings we end up with no actual feedback at all, and an unknown amount of forcing. I don’t see how that is useful in the slightest. – gavin]
gavin, apologies. Please disregard my #35 (or so, awaiting moderation) written before reading your response to my #30.
Gavin,
“You are confusing surface energy balance with the response to a TOA/tropopause forcing. Similarly, you are thinking that the Earth’s greenhouse effect can be modelled purely as an effective emissivity (i.e. ‘grey’ body). This does not actually fit the reality of why the surface temperature responds to the greenhouse effect since the emissivity itself is not independent of temperatures and greenhouse absorbers.
Are you trying to say that the 240 W/m^2 from the Sun is not forcing the climate system? The +3.7 W/m^2 from 2xCO2 is supposed to be equivalent to +3.7 W/m^2 of post albedo solar power, is it not?
The bottom line is the the 240 W/m^2 from the Sun is only amplified by a little over 60% (to about 390 W/m^2). If watts are watts, you can’t apply some nebulous new ‘feedback’ to an additional 3.7 W/m^2 from 2xCO2 and ignore the way the system is responding to the original 240 W/m^2 from the Sun.
If, as you believe, +3.7 W/m^2 is to become +16.6 W/m^2 through ‘feedback’, quantify specifically how the feedback will cause this much change on the next 3.7 W/m^2 and why it does not on the original 98+% (240 W/m^2) from the Sun. You should also explain why the planet doesn’t have an emissivity of 0.22 (3.7/16.6 = 0.22).
[Response: The basis of your error is the attempt to define sensitivity from the overall surface energy balance. This assumes a) no feedbacks and b) linearity from no atmosphere/same albedo to present day. Neither assumption is justified. See the workings of a ‘simple’ model and demonstrate to yourself that even in the simplest case your calculation does not correctly define sensitivity. When it comes to equivalent forcings from either solar (say +2% irradiance) or GHGs, sensitivity and feedbacks are very similar. – gavin]
Would you guys consider a separate small post (maybe more easily quoted for blogs) on some of the different problems with the study?
I think it would be comprehensible and hugely influential for the average reader (not anti-global warming ideologue) who sees even the “news” / blog summaries about the variation in cloud cover which is central to the article, to get the basic point that clouds are caused by related mechanisms, and not the *cause* of the described phenomena.
It may seem to require a bit of attention to the relation of clouds to forcings (a word foreign to most), but the general point of confusing (or intentionally reversing) *cause and effect* is a very, very powerful punch.
And I say “you” because people will want to quote this blog.
Speaking about papers that should not have been published, I’ve been blogging with a person who keeps insisting the greenhouse effect theory has been disproved. She keep citing news releases about “studies.” I don’t have time to follow these, but are there any peer-reviewed studies that have disproved the greenhouse effect (or thrown it into doubt), aside from one in a Hungarian science journal we discuss here sometime back (and the scientists here said it was bunk)?
Or are these just bogus “studies” that don’t really make it into a journal?
[Response: These are just bogus studies, though some have made it into (not very good) journals. See the information here: which includes various links to paper and commentaries explaining why these claims are false.–eric]
eric]
Sorry for being OT, but here’s something I just got — http://hol.sagepub.com/content/21/5/793.abstract?ct=ct — and I’m wonder what they are saying. Is it: we would be much cooler now and heading for an ice age, if not for our GHG emissions during the pre-idustrial & industrial times during the Holocene?
Are they saying that the human GHG emissions of PI times led to greater positive GHG feedbacks from nature that thought before. And in a non-human-GHG world, the cooling feedbacks during the Holocene would have been greater than thought.
Which then would mean, what, the climate is more sensitive (thru these positive warming & cooling feedbacks) in both the warming & cooling directions than thought?
Meaning ?? we’re pretty much in deeper do-do now.
Re: Hank Roberts #3 and Gavin’s response at #9.
Perhaps the following is not too far off topic.
http://www.mdpi.com has a portfolio of 60 open-access journals
listed. Of those 60, 26 are new in 2011, 10 new in 2010, and 12
new in 2009. Remote Sensing dates from 2009.
The oldest of mdpi.com’s journal is “molecules”, 1996.
A Google search will turn up some interesting comments, etc. Not sure
what, if anything, to make of it all.
#35 [gavin response] “The whole point of a forcing/feedback analysis is to be able to predict the response of the system to external perturbations”; “the system” and “external” referring to what, exactly?
[Response: Gavin’s point is a general one. If you want specifics in this case, the answer is system = ‘the earth’s atmosphere and surface’, ‘external forcing’ means the radiative forcing from extra (meaning ‘above pre-industrial levels’) CO2 and other greenhouse gases. This is what Spencer has purported to do but he has not done, because clouds are part of the ‘system’.–eric]
#35 [gavin response] “The whole point of a forcing/feedback analysis is to be able to predict the response of the system to external perturbations”. Had you said the whole point of a forcing/feedback analysis is to be able to predict the [ultimate] response of the system to external perturbations [and their consequent internal perturbations] I might have agreed with you, but you’d still have to accurately draw that line in the sand between external and internal. I don’t think you can do it convincingly. You said earlier #30 [gavin response] “indirect aerosol effects (via increased SO2 pollution, or cosmic ray modulation of ionisation) count as forcings, but the response of clouds to dynamical changes, circulation, temperature or humidity do not”. I don’t understand the reasoning behind this categorisation. It looks arbitrary to me, tendentious even.
[Response: Why? The dynamics, temperatures etc are all part of the system for which you are calculating prognostically. In a standard model without interactive aerosols or micorphysics, the impact of GCR or SO4 on nucleation and aerosol growth is simply not included. Therefore they have to be put in as a forcing. For interactive models, it is the ionisation change or SO2 etc. emission change that is the forcing. – gavin]
Gavin,
“The basis of your error is the attempt to define sensitivity from the overall surface energy balance. This assumes a) no feedbacks and b) linearity from no atmosphere/same albedo to present day. Neither assumption is justified.”
What then is controlling the surface energy balance of 390 W/m^2, which is just the net surface energy flux in an of itself? If not all the feedback mechanisms and physical processes in the climate system, then what? I presume you’re aware that the climate is a dynamic equilibrium system – not a static steady-state system. And one that is remarkably stable to boot, despite a large degree of local, regional, seasonal hemispheric, and even sometimes globally averaged variability. Hardly consistent with net positive feedback – let alone positive feedback of 300%.
I’m aware the there is some non-linearity, but relative to GHG ‘forcing’ all that matters is the global average.
Also, let’s not forget that only the Sun truly forces the system – all additional GHGs can do is slightly modify the response of the system to the forcing of the Sun. Claiming the system will respond 3 times more powerfully to a slight modification like this in such a highly dynamic – yet very stable and tightly constrained system, is an extraordinary claim that requires extraordinary proof.
You cannot arbitrarily separate the feedback mechanisms controlling the surface’s energy balance of 390 W/m^2 from those that will act on the +3.7 W/m^2 from 2xCO2 without explaining and answering the questions I posed. If you can’t answer those questions, I suggest you rethink the feasibility of a 3 C sensitivity, as some pretty simple fundamentals strongly suggest it’s way outside the system’s measured bounds.
[Response: I gave you the link above so that you could perhaps learn something. I still urge you to do so. – gavin]
i thinks y’all needs a comma in dere “what we can produce but use” (or even a dreaded semicolon) like this “what we can produce; but use” (?)
#42 [eric response] “the answer is system = ‘the earth’s atmosphere and surface’, ‘external forcing’ means the radiative forcing from extra (meaning ‘above pre-industrial levels’) CO2 and other greenhouse gases”. I’m not at all sure I even begin to understand this. I was under the impression that “external” meant “outside the system”. The only CO2 external to the system you’ve defined is overwhelmingly in the oceans. Is that what you meant?
[Response: I didn’t mean to imply that the system boundaries have to be spatial boundaries (e.g., the sides of a box containing the atmosphere). CO2 from fossil fuel burning is being added to the atmosphere quite independently of everything else. From a modeling perspective — in the context of what Spencer and Braswell are trying to do — the interaction of CO2 with the ocean and atmosphere is being entirely ignored, and that’s just fine because the timescales are totally different. Increased radiative forcing from CO2 will affect the carbon cycle on the long term, but not on the short term, and so it can be ignored. Indeed, in this context, CO2 is not being modeled at all, merely the radiative forcing at a given CO2 concentration (and that radiative forcing is obviously independent of how the CO2 got there). This is *not* the case with clouds, which are much more quickly (like in a matter of hours to days) linked with dependent on the state of the atmosphere, and so cannot be treated as ‘forcing’ in anything like a comparable way to CO2. Does that help? –eric]
I made this comment on the Unforced Variations thread, but it’s on-topic here as well: scienceblogger Greg Laden posted on the Spencer and Braswell paper yesterday. Deniers are spewing familiar nonsense in the comments, and the realists can use some expert help. TIA.
@Lynn Vincentnathan says:
30 Jul 2011 at 9:12 AM
Sorry for being OT, but here’s something I just got — http://hol.sagepub.com/content/21/5/793.abstract?ct=ct —
Are they saying that the human GHG emissions of PI times led to greater positive GHG feedbacks from nature that thought before. And in a non-human-GHG world, the cooling feedbacks during the Holocene would have been greater than thought.
Yes, seems like it. Hansen recently stated one coal-fired plant is enough to overwhelm natural variation. I’m assuming he was serious and that I didn’t misunderstand what I read.
Which then would mean, what, the climate is more sensitive (thru these positive warming & cooling feedbacks) in both the warming & cooling directions than thought?
No, just that we’ve been nudging the climate with a twig, now we’re beating the heck out of it with a club.
Meaning ?? we’re pretty much in deeper do-do now.
Actually, it’s good news. We could live like Hobbits and still maybe never have to worry about glacial periods again – assuming there is no absolute need for a healthy biosphere to go through glacials.
Thanks for doing the work/math to address this paper. As the droughts in the US continue, and the record heat waves continue, and the record breaking of record breaking continue, a lot of deniers are finding thier idolatry tested. The Spencer paper is just another idol, I think, soon to topple.
re: #40
Yes.
That’s part of an interesting special issue, which relates somewhat to the topic at hand, i.e., better paleo modles may help further constrain uncertainties. Very nice interdisciplinary issue.
Read the Introduction, 2nd page and then you can at least peruse the abstracts for free. I especially recommend the last 2 articles.