From the Georgia Institute of Technology
‘Stadium waves’ could explain lull in global warming
One of the most controversial issues emerging from the recent Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) is the failure of global climate models to predict a hiatus in warming of global surface temperatures since 1998. Several ideas have been put forward to explain this hiatus, including what the IPCC refers to as ‘unpredictable climate variability’ that is associated with large-scale circulation regimes in the atmosphere and ocean. The most familiar of these regimes is El Niño/La Niña, which are parts of an oscillation in the ocean-atmosphere system. On longer multi-decadal time scales, there is a network of atmospheric and oceanic circulation regimes, including the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation.
A new paper published in the journal Climate Dynamics suggests that this ‘unpredictable climate variability’ behaves in a more predictable way than previously assumed.
The paper’s authors, Marcia Wyatt and Judith Curry, point to the so-called ‘stadium-wave’ signal that propagates like the cheer at sporting events whereby sections of sports fans seated in a stadium stand and sit as a ‘wave’ propagates through the audience. In like manner, the ‘stadium wave’ climate signal propagates across the Northern Hemisphere through a network of ocean, ice, and atmospheric circulation regimes that self-organize into a collective tempo.
The stadium wave hypothesis provides a plausible explanation for the hiatus in warming and helps explain why climate models did not predict this hiatus. Further, the new hypothesis suggests how long the hiatus might last.
Building upon Wyatt’s Ph.D. thesis at the University of Colorado, Wyatt and Curry identified two key ingredients to the propagation and maintenance of this stadium wave signal: the Atlantic Multidecadal Oscillation (AMO) and sea ice extent in the Eurasian Arctic shelf seas. The AMO sets the signal’s tempo, while the sea ice bridges communication between ocean and atmosphere. The oscillatory nature of the signal can be thought of in terms of ‘braking,’ in which positive and negative feedbacks interact to support reversals of the circulation regimes. As a result, climate regimes — multiple-decade intervals of warming or cooling — evolve in a spatially and temporally ordered manner. While not strictly periodic in occurrence, their repetition is regular — the order of quasi-oscillatory events remains consistent. Wyatt’s thesis found that the stadium wave signal has existed for at least 300 years.
The new study analyzed indices derived from atmospheric, oceanic and sea ice data since 1900. The linear trend was removed from all indices to focus only the multi-decadal component of natural variability. A multivariate statistical technique called Multi-channel Singular Spectrum Analysis (MSSA) was used to identify patterns of variability shared by all indices analyzed, which characterizes the ‘stadium wave.’ The removal of the long-term trend from the data effectively removes the response from long term climate forcing such as anthropogenic greenhouse gases.
The stadium wave periodically enhances or dampens the trend of long-term rising temperatures, which may explain the recent hiatus in rising global surface temperatures.
“The stadium wave signal predicts that the current pause in global warming could extend into the 2030s,” said Wyatt, an independent scientist after having earned her Ph.D. from the University of Colorado in 2012.
Curry added, “This prediction is in contrast to the recently released IPCC AR5 Report that projects an imminent resumption of the warming, likely to be in the range of a 0.3 to 0.7 degree Celsius rise in global mean surface temperature from 2016 to 2035.” Curry is the chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.
Previous work done by Wyatt on the ‘wave’ shows the models fail to capture the stadium-wave signal. That this signal is not seen in climate model simulations may partially explain the models’ inability to simulate the current stagnation in global surface temperatures.
“Current climate models are overly damped and deterministic, focusing on the impacts of external forcing rather than simulating the natural internal variability associated with nonlinear interactions of the coupled atmosphere-ocean system,” Curry said.
The study also provides an explanation for seemingly incongruous climate trends, such as how sea ice can continue to decline during this period of stalled warming, and when the sea ice decline might reverse. After temperatures peaked in the late 1990s, hemispheric surface temperatures began to decrease, while the high latitudes of the North Atlantic Ocean continued to warm and Arctic sea ice extent continued to decline. According to the ‘stadium wave’ hypothesis, these trends mark a transition period whereby the future decades will see the North Atlantic Ocean begin to cool and sea ice in the Eurasian Arctic region begin to rebound.
Most interpretations of the recent decline in Arctic sea ice extent have focused on the role of anthropogenic greenhouse gas forcing, with some allowance for natural variability. Declining sea ice extent over the last decade is consistent with the stadium wave signal, and the wave’s continued evolution portends a reversal of this trend of declining sea ice.
“The stadium wave forecasts that sea ice will recover from its recent minimum, first in the West Eurasian Arctic, followed by recovery in the Siberian Arctic,” Wyatt said. “Hence, the sea ice minimum observed in 2012, followed by an increase of sea ice in 2013, is suggestive of consistency with the timing of evolution of the stadium-wave signal.”
The stadium wave holds promise in putting into perspective numerous observations of climate behavior, such as regional patterns of decadal variability in drought and hurricane activity, the researchers say, but a complete understanding of past climate variability and projections of future climate change requires integrating the stadium-wave signal with external climate forcing from the sun, volcanoes and anthropogenic forcing.
“How external forcing projects onto the stadium wave, and whether it influences signal tempo or affects timing or magnitude of regime shifts, is unknown and requires further investigation,” Wyatt said. “While the results of this study appear to have implications regarding the hiatus in warming, the stadium wave signal does not support or refute anthropogenic global warming. The stadium wave hypothesis seeks to explain the natural multi-decadal component of climate variability.”
Marcia Wyatt is an independent scientist. Judith Curry’s participation in this research was funded by a Department of Energy STTR grant under award number DE SC007554, awarded jointly to Georgia Tech and the Climate Forecast Applications Network. Any conclusions or opinions are those of the authors and do not necessarily represent the official views of the sponsoring agencies.
CITATION: M.G. Wyatt, et al., “Role for Eurasian Arctic shelf sea ice in a secularly varying hemispheric climate signal during the 20th century,” (Climate Dynamics, 2013). http://link.springer.com/article/10.1007/s00382-013-1950-2#page-1
Bart says:
October 10, 2013 at 6:08 pm
It doesn’t get discussed because it is inconvenient. Try this:
http://www.realclimate.org/index.php/archives/2007/10/my-model-used-for-deception/
Rud Istvan: “She is making predictions which should have everyone here rejoicing, not grousing.”
What I noticed immediately, which is pretty much when the predictions begin. And that’s what’s refreshing. There should be plenty of time to falsify the hypothesis, no?
Here in central Arizona we just had a very odd occurance of snow at 6500 feet in early October, with a high temp today 6 degrees below the previous record low high for the day from 1982.
Prescott similarly beat the record from 1912.
Interesting times because of the frantic insistence of the catastrophic warming cabal that we’ll fry regardless of evidence to the contrary. Otherwise, it would just be weather.
Richard M
The media will certainly miss this paper, but the “Team” will certainly not miss this paper.
The paper does not say anything about how this new model explains the pause in global warming, does not say anything explicitly against the IPCC models, it emphasizes that it is not clear how this could be applied to the 21 st century conditions. And the abstract is absolutely unreadable and does not say anything at all about any of the points raised by the authors in their media statements.
The climatology of “oscillations”, a.k.a. averages of pressure from statistical entities that have no synoptical values… Surely that should lead to processes… Not!
And, like the “heat hiding in the ocean” meme, it gives warmists a face-saving way of backing away from CAGW back to AGW. That’s the only way we can get them to dial down their calls for action now.
Wyatt here. Other lengthy posts of mine are at Judith’s site. They may answer some questions that I do not address here. First, Brian H, the quote you posted “there is nothing to tell us that CO2 is doing much to change anything” is grossly taken out of context. The running discussion at Judy’s site had been on what potential influence an external radiative forcing might have on the character of the stadium wave. The short version is that because the wave showed no change in character after about 1780, evidence was not clear on any impact that the linear forcing of ghg might have. on the other hand, a change in forcing by a quasi-oscillatory source would be consonant with network theory, whereby weak forcing of a source whose oscillation tempo was close to that of an internally oscillating index, coupled with that self-oscillator, could entrain the frequency of that intrinsic oscillator. if the oscillator was linked to other oscillators in a synchronized (not to be confused with synchronous) network, then the tempo of the entire network, and therefore the signal propagating through it, could be ‘in step’ with such an external forcing. (See Pikovsky) As the sun weakly forces, and exhibits a cadence similar to that of the stadium wave, I speculate (underline speculate, as the results must go through rigorous review) that this cycle of solar, expounded upon expertly by others on this blog and in juried papers (Scafetta, Soon, and others, for examples), may play a role in nudging the tempo of the synchronized network. Unfortunately, we had to drop solar from this paper, postponing to a future paper. Before we decided that solar’s role on the wave had to be culled from this paper, we had used numerous other solar reconstructions. Different magnitudes of the solar constant did not change the results, results which were quite good. The pattern of co-variability was our only interest. the problem came when we employed the Hoyt/Schatten updated series. it is based on five proxies. its pattern worked well. its variance strong. but unlike the other reconstructions based on tsi or ssn, the phasing of this index hit in a very curious place within the wave order. had it been the only reconstruction used for this analysis, we would have used it, unaware of this oddity. in addition, the geomagnetic ak index also co-varies with the wave, but again, phasing is different from the other reconstructions. these findings surely are speaking to dynamics captured in the solar reconstructions and how those dynamics might interact with different components of the wave, but an idea is just an idea until it can be supported rigorously. this is a goal for the next paper. All this said, I invoked another line of evidence to support this thought that the wave tempo is governed by the low-frequency component of solar. That line of evidence comes from my dissertation work with 300 years of proxy data. I noted that in my that work, the wave signal emerged in 300 years of proxy data, yet prior to ~1780, the cadence of the wave and its amplitude changed. What did not change was the orderly sequence of signal propagation. Could the changing output of the sun have been the source of this observation of strikingly modified amplitude and slightly changed tempo? it could just be bad data. it could be good data but something else. but whatever the cause, it caught my attention. Because the amplitude and tempo of the signal has remained relatively unchanged since ~1800, and this while CO 2 has been increasing, is why I stated that CO2 appears to change nothing (with respect to the wave character). I might be shown otherwise. But with what I have to look at, this is my conclusion, one not mentioned in the paper, as that was not the paper’s focus. It is my speculation based on previous work and shared in this informal dialogue. No more, no less.
It is important to be clear on what this hypothesis regards. It describes propagation of a signal through a network of synchronized, lagged ocean, ice, and atmospheric indices in a regularly occurring (not periodic) manner, averaging to ~64 years peak to peak during the 20th century. this is what our hypothesis entails. It is not the same as identifying oscillating indices that correlate with one another or of influence o temperature of combined effects of interacting ocean processes. these aspects may be a part of this scenario, but the hypothesis is much broader. To emphasize how long I have batted around this idea, sharing it with others in hopes of gaining traction,
my first work on this started in 2006. In addition to the dissertation, this is the third paper on the topic, expanding investigation into new realms with each iteration. So it is not about oscillations. It is about a secularly varying trend of a propagating signal, whose implications are broad as far as attribution and potential prediction a decade or two out.
Had we the data, testing the role of the Southern Hemisphere would be ideal. Obviously the globe does not end at the equator. And someone mentioned ocean heat. That is in our first paper, Wyatt et al 2012 with Kravtsov and Tsonis. Data are limited and caveat ridden , but interesting results, nevertheless.
It is also worth mention that another paper evolving from the dissertation was reconstructing these network indices from raw simulated model data generated by the CMIP3 data base. We applied the same methods as in the first paper (WKT 2012). We (Wyatt and Peters) used both preindustrial and industrial era runs (with prescribed annual increases in CO2 forcing. We simulate indices instead of using raw data. we do this in all related studies to effectively compress the data, effectively increasing the degrees of freedom. Not one run generated a stadium wave in the model-generated data! All model experiments were used and in most cases, at least a couple of runs of each experiment were carried out. We cannot state that we falsified the models, as that would be declaring our hypothesis to be the right one. Of course, only time and further testing can hope to be the judge of that, but how curious to have found this signal in index network after index network of instrumental and proxy data alike, but not in analogously reconstructed indices based on model simulated data points. In both the WKT and Wyatt/Peters papers, we offer discussion from broad literature reviews to both establish previous work done on links between two oscillatory processes and on work done that might highlight the features critical to signal propagation that may not be feasible to model with today’s suite of ensembles. It may also be that a network linkage may need to be incorporated into the model design. Some strides have been made in this regard. All of this is in the papers cited. Both are available free online now.
My last comment goes to character assassination. Judy has a very open mind and is rigorous in abiding only by rigorous evidence and testing. I worked with her. i know! When I began my work in 2006 on this rather novel (at the time) idea of signal propagation through synchronized indices of a climate network, few knew what to do with me. This was seven long years ago. Being a much older, and totally non-sponsored (by choice) student, I was given free rein to pursue this idea, with the only requirement that I found others to be willing to consider my idea (and join the committee). First there was Roger Pielke, Sr. He has guided me through the sometimes obstacle ridden path, challenged me to rigorously analyze and support each step along the way. no one was an “easy sell” when this idea hatched and matured. Then I presented the original work (using raw data smoothed five year) to show this propagation sequence and accompanying climate-regime evolution to Kravtsov and Tsonis of UW Milwaukee. They saw potential and came on board. After the first two papers were done, with the daily guidance on statistical applications by Kravtsov, I began investigating how the signal was propagated and sustained. Work done by Frolov et al on Eurasian Arctic sea ice piqued my interest. I explored its role in the wave sequence. I contacted Judy. She took interest in the work and joined the rather large committee. After earning the degree in 2012, I began putting together a paper based on the Arctic ice piece in my dissertation. Frolov et al, Zarkhov, and Klyashtorin and Lyubushin were all inspirational. They, and many, many others are cited liberally in the text. Point here, I was seeking a mechanism. Not the fuel to drive the intrinsic quasi oscillatory character, but the mechanism of propagation. Anthropogenic contribution was not the focus. We removed the linear trend to highlight MD variability, and in the process, certainly removed much of the ghg, but, no claim was made in the paper that we had removed the linear trend with the assumption that we were removing the full co2 fingerprint. The PR piece is the only source for that suggestion. Anyway, the point is that the pursuit was driven by the desire to understand network behavior in climate. If co2 played an obvious role in the wave behavior, we’d be the first to say so. Judy came on as co-author with not one mention of AGW or IPCC. When our work was done and results evident, it appeared clear that of the two 20th century T lulls, both coincided with the downturns of the low-frequency NHT trend. That it might suggest influence on any longterm linear trend, whatever the source or the collection of sources of that trend. The paper was published by total coincidence the week of the IPCC release. We had hoped for a shorter process, but review was rigorous, making for a much better paper, but much later publication date than we had hoped. No stone was left unturned or left unchallenged. Thus, the timing is coincidental. Assigning motive to Judy’s comments regarding the implications of our study’s findings seems unproductive, not to mention unfounded. I urge you to read the manuscript. It is posted at Judy’s site. The PDF of the publisher’s version is also available, yet behind a pay wall. I apologize for the length of this entry. There were so many comments that indicated that many had not read, just assumed. It is hard to convey a complex story with all the checks and balances described in a press release. I hope this memo helps and that you ultimately see the complete body of work for what it is – something intended to study the natural low-frequency component of climate variability with no attempt to support or refute AGW.
dbstealey says:
October 10, 2013 at 10:44 am
What we do know is that we have already lost the propaganda battle: with terms like “pause”, “hiatus”, “lull”, “stall”, and similar words, which imply with certainty that global warming will resume.
Should we propose that the “pause” could be to global warming what menopause is to reproductive ability?
The global warming menopause?
Or the global warming andropause, so Dr. Curry and Dr. Wyatt don’t think we are picking on them.
As in: “Sorry, darling, I am in the first 15 years of my andropause. But don’t worry, I’ll be back to full strength in the 2030s.”
A hilarious timing of our comments, Dr. Wyatt. No “character assassination” on my mind. Just a little play on the semantics of our public discourse.
[Charles: Please delete my duplicate post. I think I found a wordpress bug.]
“The stadium wave periodically enhances or dampens the trend of long-term rising temperatures, which may explain the recent hiatus in rising global surface temperatures.”
There were people here on WUWT saying this 6 or 8 years ago. Maybe more!
There was even a scientist on a video back then, explaining the whole warming thing to an audience and who – on video – realized this ‘stadium wave’ thing and who said, more or less, “Hey, I should look into that!”
I’ve repeated it here multiple times, but I take no credit. I actually think it is sad that it has taken this long for anyone to put it into a paper:
There is an inclining trend, with phases similar to sine waves, but on the incline. So every half cycle the slope is less, while the other half is greater. It explains the 30-year-cycles and Phil Jones’ “other” and “similar” slopes (remember his testimony after Climategate?).
1880 – 1910 – 1940 – 1970 – 2000 are all beginnings of “up” slopes (and the end of “down” slopes). The next “up” slope doesn’t come till 2030. People here have said that over and over and over again. We didn’t need Judy Curry to tell us this. But it IS time someone said it in a journal. Finally.
THERE IS NOTHING NEW ABOUT THIS – other than that a climate person put it down in a paper. And putting the name “stadium wave” to it. It could just as well have been a step wave, except that already means something altogether different.
Hahahaha – And with the up slope not due till 2030, the warmist scientists – and Al Gore – are going to all be heavy drinkers by then! 17 more years of hiatus!
Trenberth is going to be crying long before 2030.
This is a refreshing paper that is looking in the right direction for the decadal-century scale climate oscillation – a network of nonlinear oscillators and synchrony between them. Wyatt and Curry should be applauded for this.
It was said by Winston Churchill that the USA always does the right thing in the end, after they have exhausted all the alternatives. The same might be said of climate science – after all the wild goose-chase dead ends have been fully played out, what will remain will be nonlinear / nonequilibrium oscillators and emergent pattern formation plus Lyapunov stability of such systems.
This well-known video on metronomes nicely illustrates synchrony between oscillators:
Marcia Wyatt says:
October 10, 2013 at 10:49 pm
Thanks for dropping by and posting, and for the great research.
Some years ago there was a poster here who used the name “Its always Marcia, Marcia” – that was not you I guess?
“In like manner, the ‘stadium wave’ climate signal propagates across the Northern Hemisphere through a network of ocean, ice, and atmospheric circulation regimes that self-organize into a collective tempo.”
Okay, now.. . . channel Jon Stewart, (those of us who are Liberals, anyway!) and
Self-organizing!? But. . . But. . . But!. . . BUT! But ciimate is CHAOTIC! [affect a confused desperation…]
It can’t BE organized! [look into the camera…]
CAN IT???? [cue audience silence, as the camera zooms fully on his left eye iris… and fade to a beach in the Seychelles, with slowly scrolling graphic: “In the year 2125, and the sea level has risen 12 cms since the year 2000“]
@steveta_uk Oct 10, 2013 at 10:12 am:
“Does the paper suggest how strong the resumed warming signal post 2030 might be?”
As Phil Jones himself said, the slopes of the 1990 increase is pretty indistinguishable from the previous two increases.
So, expect a similar rise AND duration.
We are STILL coming out of the LIA, so the climate is doing what climate after ice ages does: IT WARMS UP OVER TIME. We are still in the middle of that warming. When will it end? Who knows? How many more stadium waves? 5? 10? 100? It will end when it ends.
@ur momisugly Mickey Reno (October 10, 2013 at 2:16 pm)
You really think eliminating IPCC would somehow magically correct the patently false assumptions made by mainstream climate “science” (e.g. Judy’s “internal” narrative)? Get the problem by the root or it will grow back in new form.
– –
@ur momisugly Salvatore Del Prete
Marcia’s brilliant contribution IMHO was figure 4 of WKT2011. There was nothing new in it. It was the way she (with some talented help from K & T) pulled all the threads together into 1 concise summary of a coupled bundle. (Contrast that with some favorite “contributors” here who spew 10s of 1000s of words to say almost nothing.)
New results on solar/ozone-gradient coherence forthcoming Salvatore …
I very much support and appreciate the paper from Marcia and Judith even though it is a reworking of propositions already published by me.
However it is only a start.
One next needs to integrate the finding into a more complete climate change description which follows the observations from beginning to end as they alternately cause warming or cooling of the climate system around the basic level of energy content determined by mass, gravity and ToA insolation.
In fact, I have already attempted that and my New Climate Model not only incorporates that ‘stadium’ wave’ as it works through the ocean basins but also places it within an overall climate change description.
http://www.newclimatemodel.com/new-climate-model/
Inter alia:
“It should be borne in mind that internal ocean oscillations substantially modulate the solar induced effects by inducing a similar atmospheric response but from the bottom up (and primarily from the equator) sometimes offsetting and sometimes compounding the top down (and primarily from the poles) solar effects but over multi-decadal periods of time the solar influence becomes clear enough in the historical records. The entire history of climate change is simply a record of the constant interplay between the top down solar and bottom up oceanic influences with any contribution from our emissions being indistinguishable from zero.”
Friends:
In my opinion the best and most important post in this thread has been provided at October 10, 2013 at 5:15 pm by Jim Clarke.
He states the present reality which we all need to face and to accept if we are to assist rapid overthrow of the zombie AGW-scare.
I copy his post here to avoid people who missed it needing to find it.
Richard
Congratulations with a very interesting paper! In addition to its own merit (quality work), its main content is a clear testable hypotheses with qualities rarely seen in climate research. As far as I can see:
1) (I believe) it has the necessary simplifying assumptions described
2) The predictions are deduceable from theory and initial conditions
3) The outcome is UNLIKELY (The probablilty they will occur for trivial or unknown reasons is low)
Cassanders
In Cod we trust
The “pause” is nothing more than the statistical impact of UHI and HADCRUT adjustments in the years up to 1995 introducing a temperature gradient in the years 1950 to 1995.
CO2 induced global warming is a myth. I recently spent some time looking at the thought experiment “Maxwell’s Demon” and it became clear to me why it is a myth. Look it up on Wikipedia and you will likely come to the same conclusions I did.
“The stadium wave signal predicts that the current pause in global warming could extend into the 2030s,” said Wyatt
Whether or not the stadium wave signal hypothesis is correct Wyatt is making the assumption that the recent plateau/decline in global temperature is a “pause” and not the start of another cycle of cooling. What us the evidence for a “pause”?
Ignoring these quasi-cyclical effects and solar relations has also lead to bias in the analysis of feedback mechanisms. The resulting over-estimation of feedbacks means that global warming outside of the range that is beneficial simply aren’t plausible.
Some might be interesting in this Econbrowser post, discussing political manipulation using science publications.
http://www.econbrowser.com/archives/2013/10/on_weights_and.html
Solomon Green:
Your post at October 11, 2013 at 4:46 am asks
The literal answer to your question is that there has been no discernible trend in global temperature at 95% confidence for at least the last 17 years but there was a discernible trend of global warming at 95% confidence for the previous 17 years.
However, the word “pause” implies an interruption to the global warming when the evidence only indicates that discernible global warming has stopped.
I am interpreting your question to be a query of the implication provided by the word “pause”, and I address that interpretation as follows.
The word “pause” implies that global warming will resume. However, that implication is not justified by the empirical evidence because a discernible trend of either global warming or global cooling can be expected to occur in future. Hence, the word “pause” implies knowledge of the future which does not exist. And that implied knowledge can be claimed to be inappropriate in a scientific discussion of the cause(s) of the existing lack of a discernible trend.
This brings us to the issue of paradigms. Scientists have a prevailing view of the appropriate theory (or theories) to adopt when conducting an analysis. Their choice of theory (or theories) is their paradigm. In hindsight it can be apparent that scientists may adhere strongly to a paradigm long after it has been surpassed by new understandings. For example, after the oxidation theory of combustion was experimentally demonstrated it did not supplant the phlogiston theory of combustion until a generation of scientists had passed away.
The prevailing paradigm in ‘climate science’ is that global temperature change is driven by radiative forcing changes induced by increased concentrations of greenhouse gases (GHGs) notably CO2 in the atmosphere. And GHG concentrations have continued to rise so according to that paradigm the global temperature will rise. Clearly, according to that paradigm the cessation of discernible global warming must be an interruption to the warming; i.e. it is a “pause”.
However, many people – including me – have never accepted that paradigm so we object to the word “pause” because it accepts that paradigm as a given.
This goes to the crux of the paper under discussion. The so-called “pause” is not explicable according to the radiative forcing paradigm alone and, therefore, the paper applies a modification to the paradigm; i.e. natural variations in the climate system can oscillate to add to or negate the warming. According to this modification the “stadium wave” has negated the warming for the last 17 years and will continue to negate it for decades in the future.
It follows from the above that the paper has two serious implications.
Firstly, and most importantly, the paper is a fall-back from the radiative forcing paradigm alone. This is typical of how paradigm shifts usually occur: the old paradigm is repeatedly modified to include unavoidable realities until the paradigm is replaced by another theory. In this case, those of us who always rejected the radiative forcing paradigm have consistently argued that natural variations in the climate were a more plausible explanation of the global warming that happened in the twentieth century (some GHG warming probably happened but was too small for it to be discernible).
So, the paper is a move from the radiative forcing paradigm alone. It incorporates some of the natural variation which those who refute that paradigm claim is responsible for discernible variations in global temperature.
Secondly, the “stadium wave” removes the suggestion of dangerous AGW. Assuming the modified radiative forcing paradigm is correct, it follows that the present “pause” was preceded by a period of warming which was enhanced by the “stadium wave”. Hence, the warming effect of GHGs over that warming period must be at most only half of the warming which occurred.
I hope this answer is clear and what you wanted.
Richard
“Roger Knights says:
October 10, 2013 at 6:27 pm
” dbstealey says:
October 10, 2013 at 10:44 am
“What we do know is that we have already lost the propaganda battle: with terms like “pause”, “hiatus”, “lull”, “stall”, and similar words, which imply with certainty that global warming will resume.
“The (neutral) term I suggest we use is PLATEAU.”
I like the term “rollercoaster.” But maybe that’s a tad “over the top.”