WUWT provided a primer on cloud feedbacks on June 12th, 2009, followed by Willis Eschenbach’s “thermostat hypothesis” also recently published. This new paper by Spencer and Braswell is in the same theme as these.
On the diagnosis of radiative feedback in the presence of unknown radiative forcing
Roy W. Spencer and William D. Braswell
Received 12 October 2009; revised 29 March 2010; accepted 12 April 2010; published 24 August 2010.
Abstract: The impact of time‐varying radiative forcing on the diagnosis of radiative feedback from satellite observations of the Earth is explored. Phase space plots of variations in global average temperature versus radiative flux reveal linear striations and spiral patterns in both satellite measurements and in output from coupled climate models. A simple forcingfeedback model is used to demonstrate that the linear striations represent radiative feedback upon nonradiatively forced temperature variations, while the spiral patterns are the result of time‐varying radiative forcing generated internal to the climate system. Only in the idealized special case of instantaneous and then constant radiative forcing, a situation that probably never occurs either naturally or anthropogenically, can feedback be observed in the presence of unknown radiative forcing. This is true whether the unknown radiative forcing is generated internal or external to the climate system. In the general case, a mixture of both unknown radiative and nonradiative forcings can be expected, and the challenge for feedback diagnosis is to extract the signal of feedback upon nonradiatively forced temperature change in the presence of the noise generated by unknown time‐varying radiative forcing. These results underscore the need for more accurate methods of diagnosing feedback from satellite data and for quantitatively relating those feedbacks to long‐term climate sensitivity.
Citation: Spencer, R. W., and W. D. Braswell (2010), On the diagnosis of radiative feedback in the presence of unknown radiative forcing, J. Geophys. Res., 115, D16109, doi:10.1029/2009JD013371.
Our JGR Paper on Feedbacks is Published
by Roy W. Spencer, Ph. D.
After years of re-submissions and re-writes — always to accommodate a single hostile reviewer — our latest paper on feedbacks has finally been published by Journal of Geophysical Research (JGR).
Entitled “On the Diagnosis of Feedback in the Presence of Unknown Radiative Forcing“, this paper puts meat on the central claim of my most recent book: that climate researchers have mixed up cause and effect when observing cloud and temperature changes. As a result, the climate system has given the illusion of positive cloud feedback.
Positive cloud feedback amplifies global warming in all the climate models now used by the IPCC to forecast global warming. But if cloud feedback is sufficiently negative, then manmade global warming becomes a non-issue.
While the paper does not actually use the words “cause” or “effect”, this accurately describes the basic issue, and is how I talk about the issue in the book. I wrote the book because I found that non-specialists understood cause-versus-effect better than the climate experts did!
This paper supersedes our previous Journal of Climate paper, entitled “Potential Biases in Feedback Diagnosis from Observational Data: A Simple Model Demonstration“, which I now believe did not adequately demonstrate the existence of a problem in diagnosing feedbacks in the climate system.
The new article shows much more evidence to support the case: from satellite data, a simple climate model, and from the IPCC AR4 climate models themselves.
Back to the Basics
Interestingly, in order to convince the reviewers of what I was claiming, I had to go back to the very basics of forcing versus feedback to illustrate the mistakes researchers have perpetuated when trying to describe how one can supposedly measure feedbacks in observational data.
Researchers traditionally invoke the hypothetical case of an instantaneous doubling of the CO2 concentration of the atmosphere (2XCO2). That doubling then causes warming, and the warming then causes radiative feedback which acts to either reducing the warming (negative feedback) or amplify the warming (positive feedback). With this hypothetical, idealized 2XCO2 case you can compare the time histories of the resulting warming to the resulting changes in the Earth’s radiative budget, and you can indeed extract an accurate estimate of the feedback.
The trouble is that this hypothetical case has nothing to do with the real world, and can totally mislead us when trying to diagnose feedbacks in the real climate system. This is the first thing we demonstrate in the new paper. In the real world, there are always changes in cloud cover (albedo) occurring, which is a forcing. And that “internal radiative forcing” (our term) is what gives the illusion of positive feedback. In fact, feedback in response to internal radiative forcing cannot even be measured. It is drowned out by the forcing itself.
Feedback in the Real World
As we show in the new paper, the only clear signal of feedback we ever find in the global average satellite data is strongly negative, around 6 Watts per sq. meter per degree C. If this was the feedback operating on the long-term warming from increasing CO2, it would result in only 0.6 deg. C of warming from 2XCO2. (Since we have already experienced this level of warming, it raises the issue of whether some portion — maybe even a majority — of past warming is from natural, rather than anthropogenic, causes.)
Unfortunately, there is no way I have found to demonstrate that this strongly negative feedback is actually occurring on the long time scales involved in anthropogenic global warming. At this point, I think that belief in the high climate sensitivity (positive feedbacks) in the current crop of climate models is a matter of faith, not unbiased science. The models are infinitely adjustable, and modelers stop adjusting when they get model behavior that reinforces their pre-conceived notions.
They aren’t necessarily wrong — just not very thorough in terms of exploring alternative hypotheses. Or maybe they have explored those, and just don’t want to show the rest of the world the results.
Our next paper will do a direct apples-to-apples comparison between the satellite-based feedbacks and the IPCC model-diagnosed feedbacks from year-to-year climate variability. Preliminary indications are that the satellite results are outside the envelope of all the IPCC models.
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Almost there.
A plot of precipitation by latitude over lapse rate by latitude over solar input by latitude shows the hadley heat pump convection engine clearly.
Not only is it ‘difficult’ to pick out any radiative feedback signature, it’s moot because you are talking about a convection engine that is a constant flow. All the gases go to the refrigerator in the sky all the day and all night long, just removing what the surface can radiate and conduct to them.
If you improve the heat capacity of the working fluid, you can only improve the efficiency.
Interesting that LGF posted Dr. Spencer’s paper with the encouraging comment,
“You know you want to understand what he thinks, even if it is to prove him WRONG!”
Tagged: Denialist
I take it Journal of Geophysical Research is the new home of the “denialists”.
It is good to see Charles Johnson has an open mind and is willing to honestly discuss things that may not adhere to his ideology, not.
Ric Werme, I’d like to see an update of your web page “Science, Method, Limatology, and Forgetting the Basics” in light of the much longer solar cycle than even you originally anticipated. While some out there are screaming “hottest decade ever”, I think other factors are working against them.
I read Dr. Spencer’s book back in April and wondered when this seminal work on feedback would be published. I am glad Dr. Spencer was persistent in accommodating the hostile reviewer so that it it finally appears in the peer reviewed literature.
Congratulations, Dr. Spencer. I am now looking forward to your next paper.
I now wonder if any of the computer models will be adjusted to fit these new results.
Thanks Roy and William, though the truth is just dripping in right now, at least it is climate scientists like you both, and I’ll include Dr. Christy and many others, that are helping to keep the spigot ajar. If given their way, these dishonest “climatologists” would twist it completely off.
I have read once people over at Real Climate claiming that Spencer always advertises his work in a way that inflates the level to which what has been said in his papers challenges the majority position in climate science. I thought that was just their jealousy and a part of the smear campaign against the skeptical scientist whose research is dangerous to their agenda.
However, this new paper seems to indirectly confirm their allegations. This new paper was extensively promoted by dr Spencer for months as a breakthrough that would finally prove that the climate feedbacks are dominantly negative and that the climate scientists were fooled by Mother nature into believing in the positive feedbacks. From the abstract above we can see nothing of the sort. The conclusion is that a “more accurate measurement is needed”.
The basic idea that the diagnosis of the feedbacks was biased by not taking into account the natural cloud variability, an “internal radiative forcing” of the climate system is well known from the previous Spencer and Braswell paper from 2008. What is new here? We know nothing about the real feedbacks, just as we did not know before. What exactly changed in the state of knowledge of the climate science about the feedbacks with this paper?
This is a groundbreaking study!
A true iceberg gash in the hull of the USS CAGW.
Chris
Norfolk, VA, USA
Dr. Spencer, your data given is more than welcomed. On first scan of your paper, without delving into the fine details yet, when just viewing your Figure 1 and Figure 3 data, it appears the by the satellites our climate system is very close to a totally randomized system. Figure 3 does show a very small warm tendency over this period but it is mostly counteracted by rather large random cooling excursions irregardless of the current forcing, plus or minus. Very interesting. Hope I’m interpreting that right. I’ll read on.
The fact that this paper survived a rough review process means it is better than it might have been. Recall the old saying “If it doesn’t kill me, it makes me stronger.” Let us all wish Dr. Spencer all the best with future publications that both shine light on climate science misunderstanding as well as advancing the state of the art.
Here is an intense and well-written editorial which succinctly puts it all into perspective.
And yes, Dr. Spencer is mentioned.
An Al Gore is mentioned a few times, too. LOL
Read it. It is worth it.
http://www.washingtontimes.com/news/2010/aug/24/al-gores-global-warming-crusade-shrinks/?page=1
Chris
Norfolk, VA, USA
….our latest paper on feedbacks has finally been published…
Einstein had troubled getting published too. You’re in good company.
Congrats!! All the hard work is finally getting where it belongs.
RockyRoad says:
August 28, 2010 at 8:28 pm
Updating that is pretty high on my list of stuff to do, but there’s a lot of competition, both climate-wise and other-wise. I’m actually inclined to deemphasize the solar aspect (I have a lot of respect for Leif), but it’s something that’s fairly easy for people to relate to. The biggest challenge may be to keep the information level fairly low – that essay has to be accessible to people who are jsut beginning to look into the subject.
It might be time for a Page 2 that goes into topics in more detail. I’d also like to mention the dichotomy of people in a tizzy about the warmest year ever in 1998, then the warmist decade ever because the year-to-year trend was down, back to the warmest year ever only seven months into the year, all compared to cold years being just weather and far too short a period to be climate.
Ivan… You question what is new in this paper and what advancement of the knowledge base does it possess.
Well it shows that the AGW Hypothesis is flawed… I would have thought, that alone would be enough?
It is not up to Dr Spencer to try and explain the vagaries of Natural climate change when showing the flaws in the AGW hypothesis…. Just show that natural variation is a valid explaination for the observed measurements.
It is up to the AGW proponents to show that Anthopogenic CO2 is having a profound effect on climate and to explain that in a scientific way. After all, it is they who are hypothesising an effect on the natural system. Surely they can show it without flaws…. and surely it is upon them to understand the natural system before attributing anthropogenic changes to it.
Gentlemen, congratulations upon your achievement! I’m looking forward to diving into the paper as soon as possible.
Maybe I’m missing something but it seems to me that the data in Figure 1 (of the paper) tells a pretty simple story. Firstly LW+SW depends only weakly on T. With r^2 around 0.2 the regression on T explains only about 20% of the variability in LW+SW; so 80% depends on something else. To the extent that this dependence is real the data show an increase in LW+SW for an increase in T, as expected without any feedback, or with some negative feedback. But I think this is inconsistent with a dominant positive (with respect to T) feedback, which should show a decrease in LW+SW (heat being trapped more) with increasing T. What am I missing?
Interesting comment over at RC:
“Some of Spencer’s blog followers will need to selectively agree w/him on his feedback paper while still emphatically disagreeing with his heretical refusal to comply with G&T dogma. Deemed definitely wrong on a fundamental matter, correct on something else much more subtle, a strange and tense heterodoxy but the man is too valuable to be discarded as an apostate.
Tough row those folks must hoe, positively rocky.”
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Uhhhh…. too valuable to be discarded as an apostate???
Reading this, I cannot shake the images from Bladerunner, of the always wet, humid conditions in L.A.
CRS, Dr.P.H. says:
August 28, 2010 at 11:12 pm
Interesting comment over at RC:
“Some of Spencer’s blog followers will need to selectively agree w/him on his feedback paper while still emphatically disagreeing with his heretical refusal to comply with G&T dogma. Deemed definitely wrong on a fundamental matter, correct on something else much more subtle, a strange and tense heterodoxy but the man is too valuable to be discarded as an apostate.”
Typical of the pseudo-intellectual bullshit that RC commenters excel in.
“Dr. Spencer’s book should become a standard in science and philosophy classrooms where scientific method is alive and well.”
It just needs a grabbier title (maybe for his next book?): An Inconvenient Goof.
“while still emphatically disagreeing with his heretical refusal to comply with G&T dogma”
Gin & Tonic?
I’d always thought the Real Climate gang were most likely suffering from a surfeit of those strange “herbal” cigarettes……
Excellent article. I will have to read it a few more times to digest it.
I do think that this is where our effort should be concentrated. Rather than squabble with AGW proponents about sea ice thicknesses and Siberian temperature records I think that we need to expose the models for the weak and flimsy approximations that they are.
It really has to be stressed that these models are no more than guesses and any claims to long term accuracy are blatant lies.
THIS is where the battle needs to take place.
Congratulations Roy and William! Took some time and effort to get , but worth it in the end.
The next IPCC report will have to include the knowledge in your paper when discussing the validity of climate models ‘predictions’. Politicians need to be aware of the uncertainty of results.
DocMartyn says:
August 28, 2010 at 6:44 pm
“The models are infinitely adjustable, and modelers stop adjusting when they get model behavior that reinforces their pre-conceived notions.”
Which means they are not models, they are fits.
My aunt Agatha used to have fits. And yes, she too would stop when she got what she wanted.
wayne says:
August 28, 2010 at 9:11 pm
“…when just viewing your Figure 1 and Figure 3 data, it appears the by the satellites our climate system is very close to a totally randomized system. Figure 3 does show a very small warm tendency over this period but it is mostly counteracted by rather large random cooling excursions irregardless of the current forcing, plus or minus…”
What we observe to be ‘random’ is actually the result of turbulence and our climate system is driven by deterministic chaos, not random chance.
Here’s a good example of some of the features which our non-linear global weather / climate system displays (can be slow loading the animation):-
http://cimss.ssec.wisc.edu/tropic/real-time/tpw2/natl/anim/latest72hrs.gif