Dr. Roy Spencer from The University of Alabama at Huntsville will be presenting a special seminar at CU Boulder in the CIRES Auditorium on Thursday, July 17th, based on the Journal of Climate paper (in press):
Spencer, R.W., and W.D. Braswell, 2008: Feedback vs. Chaotic Radiative Forcing: “Smoking Gun” Evidence for an Insensitive Climate System?
Abstract
“A simple model and satellite observations are used to demonstrate that previous diagnoses of climate feedbacks from the satellite record have a strong bias in the direction of high climate sensitivity (positive feedback). The source of the bias is chaotic radiative forcing generated within the climate system, most likely due to low clouds. Through analysis of frequency histograms of local regression slopes computed throughout the low-pass filtered time series of temperature and total (reflected shortwave SW and emitted longwave LW) radiative fluxes, the radiative forcing signal is shown to have a unique signature separate from the feedback signature. The global oceanic averages of satellite CERES data during 2000 through 2005 reveal a net (SW+LW) feedback parameter of around 8 W m-2 K-1. This strong negative feedback signal exists independent of the low-pass filter time scale, from 10 day to 2 years. In stark contrast, IPCC AR4 models analyzed with the same method all exhibit positive feedbacks of various strengths. It is suggested that the unrealistically high sensitivity of the climate models is the result of a misinterpretation of the co-variability of clouds and temperature when specifying cloud parameterizations. Since only radiative feedback has been assumed in feedback analysis of natural variability (clouds being forced by temperature), the presence of chaotic radiative forcing of temperature by clouds causes the false appearance of positive feedback. In short, cause and effect have been confused. Finally, if such a strong negative feedback has indeed been operating on multi-decadal time scales, this means that the radiative forcing from anthropogenic greenhouse gas emissions is not nearly strong enough to explain the 1°C warming in the last century.”
The pdf of the ms powerpoint presentation is here.
Climate Science: Roger Pielke Sr. Research Group News: Special Guest Seminar at CU by Roy Spencer, July 17, 2008:Global Warming: Recent Evidence for Reduced Climate Sensitivity
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Can anyone see any flaws in Spencer’s & Braswell’s arguments of internal radiative forcing & low climate sensitivity?
Part of it is speculative; that part which attributes slight changes in cloud cover to fluctuations in atmospheric & oceanic circulation changes. However even this part makes compelling reading and certainly a good case is made for more extensive research into this aspect.
After reading the recent papers of Forster, Gregory & Taylor, and associated papers, I was struck by two things. One their results appeared very preliminary. Associated with this much of it was very speculative & they were ringed with contradictions & doubts. Take this paragraph from Forster & Gregory, AMS, Jan 2006, p50, on clouds as representative of much of this: –
“c. Clouds
The NET cloud feedback appears close to neutral in
the scanner data; it is made up of components due to a positive SW feedback and negative LW feedback of around 2.0Wm ^-2 K ^-1 each (Fig. 6). Soden et al. (2004) point out that this feedback is not representative of the actual cloud feedback term. However, we are still able
to compare it to similar diagnostics from other models. One model out of the 10 models presented in Fig. 7.2 of the 2001 Intergovernmental Panel on Climate Change (IPCC) report had a similar cloud radiative forcing feedback (Houghton et al. 2001); other models behaved quite differently. As the clear-sky Y values from the scanner data (Fig. 6) resemble the total Y values for the
Pinatubo response (Fig. 4), it is interesting to speculate that this may indicate that Pinatubo caused few cloud changes.”
Yet according to the IPPC clouds give a positive feedback! Based on what; this??? They were obviously based on bias & faulty analysis and models with incorrect assumptions feed in. It amazes me that good scientists can put together an hypothesis (large positive feedback) that neglects the possibility (they apparently didn’t even discuss it in publication!) that cause and effect may be the other way round.
I would love to be at Spencer’s & Braswell’s presentation at the University Of Alabama in Huntsville this Thursday. My prediction; expect to see many more scientists coming on board with this work in the near future.
This research IMO has many similarities with the work of Barry J. Marshall and J. Robin Warren who received the Nobel prize for their discovery of “the bacterium Helicobacter pylori and its role in gastritis and peptic ulcer disease”. They found the bacterium in 1982 & it took them 2 decades of argument against the prevailing dogma that stress and lifestyle were considered the major causes of stomach and intestinal ulcers. Sound familiar? Don’t expect Spencer & Braswell to turn this around anytime soon; there are large & influential vested interests intent on maintaining the current dogma of catastrophic AGW. Too many reputations & egos to protect. However it will turn around; we are in for an interesting period, at the scientific, economic & political levels.
http://www.medscape.com/viewarticle/514219
All good points, Geoff. Too bad there isn’t a way for Spencer & Braswell to do spectacular experiments which attract world wide media sympathy as Marshall & Warren finally did.
The only good news is that the jack-booted Gaia thugs will no longer have the leg of science to stand on.
But science will be overthrown because of this and other failures.
Eventually, the shooting starts.
““A simple model ”
sweet irony.
Comment from an attendee at Roy Spencer’s seminar yesterday at Boulder, Colorado, US; taken from Steve McIntyre’s CA blog.
http://www.climateaudit.org/?p=3258#comment-277300
“Orson says:
July 17th, 2008 at 11:01 pm
I managed to make Roy Spencer’s presentation today at CIRES, University of Colorado at Boulder. (cf #79, Jim Arnt) He elaborated on his work since last year on climate sensitivity, and it is now in press at Journal of Climate.
He comes to a 0.25 C per century delta-T estimate. Mind you, this is derived on only six years of data. Clearly, more and better will yield more and better representations of reality. What stands out starkly is that we have the first realistic modeling of the global climate system in Spencer’s work. As I commented during Q&A, “there is lots left to explore.” Dr Spencer agreed.
He pitted his empirically derived model against selected IPCC models. None of the latter stood up well.
Two points of humor: he named (something important-I’ll check notes later) “the Hansen effect.” The “Smoking gun” in his title was to tweak Hansen for his infamously titled paper wherein he projected catastrophe.
He asked if anyone from (nearby) NCARs climate modeling program was in attendance? No voices or hands went up. He quipped something about some people having a problem with reality….
His line of thought conveyed how a meteorologist thinks practically about climate and its subtleties, as opposed to most modelers, typically trained in math (Connelley) or physics (astro- in Hansen’s case) or other fields, who think more categorically, unable to see tenuous connections in brut nature that meteorologists only find natural.
For instance, the modelers assume the climate system is naturally in equilibrium unless disturbed from the outside, like from mankind. His satellite evidence shows how climate trends tend to persist, on up to decadal timescales, because of internal forcings. But climate never actually equilibriates as these modelers presuppose.
In just the last days or weeks, he has integrated some insights on ENSO and other known oceanic circulatory phenomenon as climatic drivers that he has been pulling together since January (cf. Anthony Watts web site) on natural climate drivers.
Th BIG point is that internal climate variability has been mis-identified, heretofore. His model was matched against Forster (et Al, 2006), and improved on his results, indicating that his results are veridical.
His new insight is that ocean PDO-neg and PDO-pos effects are likely driving a more dominant natural climate effect, and his results are unlikely to be coincidental. Forster agreed.
It was an almost full house, maybe 70 (out of 100) seats filled. He says his PP presentation should be up at Roger Pielke (Sr?) web site now, he said.
(Too busy right now to check details right now – this all from memory after work – THIS was full of interest for people here.) I’ll try to fill in gaps later, and see the PPP myself to refresh my notes and memory.
There were also two interesting working elements on display here. First, the fact that he’s doing this all on Excel spreadsheets, not the multi-million dollar super-computers with teams of well-paid researchers like the modelers. Second, when someone asked if he had communicated with Bill Gray, Spencer said he had not seen Bill in ten years time, but bumped into him while registering at a conference awhile ago. Dr Gray got down on his knees and reportedly said “I love you!” “Kind of embarrassing,” said Spencer smirkingly, admitting that Gray is very passionate about observationally driven climate science. NOT what’s become of it these days.
Again, see the PPP at Pielke’s web site for Spencer’s compelling conclusions and implications for what this means for climate modeling. And again, this work opens up a lot more work to do to confirm his teasing inferences.
Spencer admitted to having engaged in the kind of “handwaving” often criticized at CA. But now there are increasing amounts of hard empirical evidence to back up such previously idle claims. Quite fascinating. Could this be a turning point in the theory versus observational debate that has characterized the field since the demise of the Hockey Stick?”
Any idea why in the beginning of Spencer’s presentation he uses an ocean mixed layer depth of 50 m and that at the end he uses a mixed-layer depth of 1000 m?