Here’s figure 18, which I found interesting, especially the red line. – Anthony
Guest post by Bob Tisdale
Today, blogger “slimething” left me a link to the Karnauskas et al (2012) paper A Pacific Centennial Oscillation Predicted by Coupled GCMs. Thanks, “slimething”.
I’m not going to offer any thoughts, because I don’t want to influence your comments, but I did highlight the two concluding sentences in the following abstract for you, and I’ve also reproduced the two implications listed in the Summary and concluding remarks.
ABSTRACT
Internal climate variability at the centennial time scale is investigated using long control integrations from three state-of-the-art global coupled general circulation models. In the absence of external forcing, all three models produce centennial variability in the mean zonal sea surface temperature (SST) and sea level pressure (SLP) gradients in the equatorial Pacific with counterparts in the extratropics. The centennial pattern in the tropical Pacific is dissimilar to that of the interannual El Niño–Southern Oscillation (ENSO), in that the most prominent expression in temperature is found beneath the surface of the western Pacific warm pool. Some global repercussions nevertheless are analogous, such as a hemispherically symmetric atmospheric wave pattern of alternating highs and lows. Centennial variability in western equatorial Pacific SST is a result of the strong asymmetry of interannual ocean heat content anomalies, while the eastern equatorial Pacific exhibits a lagged, Bjerknes-like response to temperature and convection in the west. The extratropical counterpart is shown to be a flux-driven response to the hemispherically symmetric circulation anomalies emanating from the tropical Pacific.
Significant centennial-length trends in the zonal SST and SLP gradients rivaling those estimated from observations and model simulations forced with increasing CO2 appear to be inherent features of the internal climate dynamics simulated by all three models. Unforced variability and trends on the centennial time scale therefore need to be addressed in estimated uncertainties, beyond more traditional signal-to-noise estimates that do not account for natural variability on the centennial time scale.
From the Summary and concluding remarks:
1) If nature exhibits such strong natural variability of tropical Pacific SSTs on centennial time scales, then assumptions that the observed trend over the past century to a century and a half is a response to radiative forcing are tenuous. It could in fact be that the observed trend over the past century and a half is merely reflective of internal variability. If so, it could strengthen or weaken in the future as the natural variability evolves. This will combine with, and potentially interact with, any forced response and thus have implications for tropical Pacific and global climate.
2) If the centennial variability in the models is spurious, then it nevertheless is a robust component of the three analyzed models, is likely to exist in other models, and therefore will continue to influence coupled GCM projections of future climate, as well as initialized decadal hindcasts and forecasts conducted with GCMs. In all cases, it must be known at what stage the natural centennial variability exists at the beginning of a forecast or projection to isolate the forced change from the modeled internal variability.
After reviewing the paper briefly, one interesting thing I noted is that, even though two of the authors are from Columbia University, they did NOT use NASA GISS Model E in their study. Model E apparently isn’t nearly as good as the codes that were cited (GFDL CM2.1, CCSM4, ECHO-G). Certainly those codes are much better documented than Model E. Of course, NASA GISS can’t be bothered with such trivialities as documentation of their GCM software – they are too busy blogging and making extreme statements about the oil and coal industries.
My study of the change in global maximum temps. (who nobody but me is plotting) suggests a cycle of ca. 88 years, probably the Gleisberg cycle.
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
Can you believe that we are heading for a few of the darkest and coldest winters yet in the NH and nobody has even picked up full well where we are headed……
mind you maxima is like energy in which lags a bit on energy out.
Quite a few commenters are missing the either/or proposition contained in conclusion points 1 and 2 in the post.
The model output varies as much as 100% of the actual data, eyeballing the graph. Strike one.
Future model projections are even greater. Strike two.
The authors used the word robust more than twice, trying to impart significance. Strike three.
Get this B.S. outta here.
Looks like the climate computer models could be worse than we thought!
Sparks says:
“What are your thoughts on pulsar timing cycles? Atomic clocks are based on these cycles, they appear very precise but over the long term, lets say half a million years do you think they slow down and speed up?”
The period of atomic clocks is determined by an atomic energy level transition in a beam of cesium or rubidium atoms. The period of pulsars is the rotation frequency of the neutron star at the center of the pulsar. There is no relation here.
Pulsars do slow down in discrete steps of very small magnitude. It is generally believed that this is due to “starquakes,” microscopic shifts in the neutronium that makes up the neutron star. It is amazing that we can detect a microscopic shift in an object that is 10’s, hundreds, or thousands of light years away.
I have to agree generally with several who have already commented, notably Grant Brown, nuclearcannoli and BillC. Others are underwhelmed by the paper apparently because it is very weak support for any claim(s) about how the climate system actually works on the centennial scale. Granted. But it is worth bearing in mind that those of us who flat out oppose or are unconvinced by the IPCC “settled science” are not just involved in a purely scientific dispute with the IPCC, but also in a rhetorical war with its acolytes. The paper represents a big, fat, juicy forensic plum that has been dropped into our laps! We can say, “Three of the best of your own damn models spontaneously produce centennial scale cycles with no external forcing by GHGs or anything else, cycles which produce long term trends in SSTs. Maybe most of the other models do so as well. Thus, assuming your models are worth anything to begin with, they simulate large natural internal climate variability that could account for much of the warming we have actually seen. . . .etc. . .etc.”
At last we are seeing some sanity getting back into published climate science.
The predictions hightlighted in the graph shown above echoes the cyclic analysis shown over at Judith Curry’s site and is close to Scaffetta’s work.
http://curryja.files.wordpress.com/2012/03/icoads_monthly_adj0_40-triple1.png
That plot comes from an article which shows Hadley adjustments effectively remove the long term variations from the SST record.
http://judithcurry.com/2012/03/15/on-the-adjustments-to-the-hadsst3-data-set-2/
Thanks Bob, this is an excellent and important study, a serious attempt to encompass multidecadal cycles in a GCM. The ECHO-G model is quite provocative (fig 18). The section b under results, “a proposed mechanism” contains a very useful discussion which actually includes ideas that Bob has been developing such as the symmetry / asymmetry of heat discharge / recharge of ENSO events and the role this plays in multidecadal climate warming (or cooling) i.e. its ENSO wot dunnit. Plus a recognition of Bjerknes feedback. Plus recognition of nonlinear oscillation. Light at the end of the tunnel of the current climate science dark age?
One final observation. We are wired to find patterns where none exist, and while intuitively I feel our long term stable climate must have cycles to maintain that stability, I am cautious about labelling things cycles.
One thing that raises a red flag for me is where a cycle appears to be symmetrical. That is, the down phase is the mirror of the up phase. There is no reason for this to be the case in a complex system – just look a graph of glacial and interglacial phases of our current ice age – and I suspect this expectation of symmetry is part of what’s wired into us.
So, my conclusion is the centennial cycle in the models is likely just unconscious bias by the modellers, expecting symmetrical cycles in the climate. At least until someone comes with data that shows this cycle.
Philip Bradley says
One thing that raises a red flag for me is where a cycle appears to be symmetrical. So, my conclusion is the centennial cycle in the models is likely just unconscious bias by the modelers, expecting symmetrical cycles in the climate.
Henry says
I would tend to agree with you if we are looking at average temps. on earth, i.e. the mean
Namely, earth has so many, many places where it stores energy, like in water, in chemicals, in vegetation etc. so that what is bound to come out (energy-out) looks strange and unrecognizable in terms of patterns.
However, in my case I Iooked at maximum temperatures, which is like an evaluation of energy-in. Looking at the deceleration of warming on the maxima, I was stunned to find that it seemed to follow on a bi-nominal curve and the correlation I got for that was 0.998. Eventually I realized that it must be like an a-c-wave and of course that is symmetrical.
http://wattsupwiththat.com/2012/10/03/new-paper-predicts-sst-temperature-based-on-pacific-centennial-oscillation/#comment-1100779
I have already figured out what mechanism causes this wave, more or less.
Henry, I and a number of others agree with you about the significance of maximum temperatures. Max temps are a better metric of the heat gain of the climate system than averages, and that is what the debate is about.
Henry@Philip
Thanks Philip, I am glad you guys have picked up on it.
Just now, I felt a bit like having peed in my (black) pants: you get that warm feeling of having “done” something, nut nobody notices it.
Never mind, I am probably further ahead then any of my countrymen in South Africa in this field and that should make me feel good.. It is now a bit like it was in the past when I had finished a job or investigation:
what are we going to do with the results?
It looks we are heading for quite a bit of colder weather in the years ahead, but it is not like we have never been there before….