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
JC presents a lot more plausible explanation than the whole IPCC process, which is hamstrung by consensus.
Wow!
Refreshing.
But where is the sun?
This seems like a stretch. I’m going with the variable Sun.
Does the paper suggest how strong the resumed warming signal post 2030 might be?
This is all very interesting and might well be right, I certainly focus my interests on these multi decadal cycles with 90 percent of my comments and reference page checking. But modeling such long cycles is disingenuous given the data availability and data quality issues. I thought we already suffered from the conversion of these cycles into constants in current models to guarantee large forecast error and the same goes for solar cycles. This is like trying to predict Great Depressions with only one or maybe two such events in the data set. How can you even begin to claim uniformity of those cycles relative to the data universe? I would still call this study progress for opening the door for global and regional cooling trends upcoming from these important cyclical components. Thank you both for shining more light on these important cycles.
“…a reversal of this trend of declining sea ice”. Without this ‘poster child’ of AGW, the warmists will be screwed.
“Marcia Wyatt is an independent scientist.” Yep, as sadly Academe now only welcomes paid-up Consensus believers.
So are they saying that CO2 is warming the planet measurably, and the wave is currently cancelling these measurable CO2 effects predicted by the AGW crowd, but when the wave is not cancelling these CO2 effects, watch out? Or does this say CO2 has no measurable effect on climate?
A simple (e.g., linear) extrapolation of temperatures based on an upswing of such a wave would over-predict future temperature increases. Likewise basing it on a downswing would under-predict increases.
In the case of climate models, “tuning” the parameters to fit an upswing would also over-predict temperature increases, since these models do not allow for such waves. So I guess the questions are (1) does this wave truly exist, and (2) have climate modelers tuned their models to an upswing of this wave?
Judith Curry or the IPCC?
That’s a complete no brainier.
The first is competent and flexible, while the second is a bloated bureaucratic ineptocracy, only interested in its own self-preservation.
DaveR says:
October 10, 2013 at 10:11 am
This seems like a stretch. I’m going with the variable Sun.
A seventh-inning stretch?
Multichannel SSA? Cool. I use that all the time.
I’ve recently developed a more robust version based on tensor rather than matrix rank reduction. I wonder if it would improve the analysis.
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.
I am not convinced. Completely disregarding the Southern Hemisphere may give credence to this new model, but it comes at the cost of credibility. This is simply cherry-picking the location [the Arctic] that supports the new model.
Global sea ice is not declining, it is at about its long term [30+ year] average.
I also do not like predictions that will take decades to validate. Everyone seems to be making predictions for the 2030’s, the 2040’s, and longer. They were completely wrong in all of their previous predictions; why should these farther out predictions be any better? I smell grant trolling.
I think there are more basic climate factors that caused the 16.8 year pause in global climate . These are, a much less active sun, a changing global ocean SST cycle which is headed for cooler ocean surface temperatures and a cooling Arctic due to changing deep ocean currents. Volcanic eruptions can also alter global weather but their effect only lasts for a few years and their timing is unpredictable. However whether you accept that the sun or the oceans or both as the prime climate drivers, both factors seem to point to possible 30-35 years of cooler weather rather than unprecedented warming. If we are also entering the start of the trough period of a longer 110+ year climate cycle as a result of three low solar cycles which occur every 100 years or so, then we may have even colder weather than the typical ocean driven 60 -70 year climate trough. This was the case during, 1790-1820 and again 1880-1910 troughs which were colder than the 1945-1975 trough. In either case the winters may be getting progressively colder for the next several decades. Winters during the next few years will get colder and most likely by 2018/2020 will be much colder than today. The winters could stay cold for the next several decades. This colder period can be moderated by warmer El Nino periods which typically occur every 3-7 years, however, there are also fewer strong climate alerting El Nino’s during cooler periods [only one per decade]. Land locked areas like Central US, Central Canada (especially the Prairies), Central Europe and Asia which do not get the moderating effect of the oceans could have colder winters than the coastal areas.
Key words that stood out to me were “statistics”, “could”, and “unknown”.
Curve fitting is at best a tricky art. It would be nice to see physical mechanisms presented.
Well, I don’t know whether there is enough data available to draw the conclusions that this paper suggests, but at least the hypothesis seems plausible compared to the usual nonsense we frequently see like Trenberth’s deep diving ocean heat. Also, unlike many other fanciful notions advanced recently to explain the hiatus we should not have too long to wait to begin to confirm or falsify some of the conclusions put forward by this paper e.g. sea ice recovery.
Go Home says:
October 10, 2013 at 10:24 am
Exactly: the “stadium wave” speaks to variability but not to the underlying trend. However, if the pause portion is a SW modification, then there is a component in the pre-pause that has to be attributed to the SW.
What the Stadium Wave theory does is reduce the possible A-CO2 effect. Taken with probable (my work and opinion) component of increased insolation reaching the ground (less clouds), there isn’t much room for significant radiative forcing in CO2 (on a practical, results-of, scale).
Wyatt and Curry’s paper is surely interesting. It clarifies how several subsystems of the Earth are linked to each other. And it confirms my (numerous) studies published since 2010 that “the current pause in global warming could extend into the 2030s” because of the quasi 60-year natural cycle.
However, this work misses the major physical issue because it misses to explain the origin of the pattern itself. The key problem refers to this sentence “The AMO sets the signal’s tempo”. The paper does not tell us what is making the AMO to oscillate in the first place with a quasi 60-year cycle.
As extensively demonstrated in the scientific literature (in particular my papers) this oscillation correlates with solar/astronomical oscillations. Thus is very likely of astronomical origin.
To know more on the topic visit my web-site:
http://people.duke.edu/~ns2002/#astronomical_model
Or read my latest work, e.g.
Scafetta, N. 2013. Discussion on climate oscillations: CMIP5 general
circulation models versus a semi-empirical harmonic model based on
astronomical cycles. Earth-Science Reviews 126, 321-357.
DOI: 10.1016/j.earscirev.2013.08.008.
http://www.sciencedirect.com/science/article/pii/S0012825213001402
This paper contains a detailed analysis of all CMIP5 models used by the IPCC, and demonstrates that they do not reproduce the decadal and multidecadal patterns since 1850 (not just the temperature standstill since 2000, the failure is nearly total). The paper extensively discusses my astronomical based model since the Medieval Warm Period and demonstrates its far better performance than the CMIP5 models.
Abstract:
Power spectra of global surface temperature (GST) records (available since
1850) revealmajor periodicities at about 9.1, 10–11, 19–22 and 59–62 years.
Equivalent oscillations are found in numerous multisecular paleoclimatic
records. The Coupled Model Intercomparison Project 5 (CMIP5) general
circulation models (GCMs), to be used in the IPCC Fifth Assessment Report
(AR5, 2013), are analyzed and found not able to reconstruct this
variability. In particular, from 2000 to 2013.5 a GST plateau is observed
while the GCMs predicted a warming rate of about 2 °C/century.
In contrast, the hypothesis that the climate is regulated by specific natural
oscillations more accurately fits the GST records at multiple time scales. For
example, a quasi 60-year natural oscillation simultaneously explains the
1850–1880, 1910–1940 and 1970–2000 warming periods, the 1880–1910 and
1940–1970 cooling periods and the post 2000 GST plateau. This hypothesis
implies that about 50% of the ~0.5 °C global surface warming observed from
1970 to 2000 was due to natural oscillations of the climate system, not to
anthropogenic forcing as modeled by the CMIP3 and CMIP5 GCMs. Consequently,
the climate sensitivity to CO2 doubling should be reduced by half, for
example from the 2.0–4.5 °C range (as claimed by the IPCC, 2007) to 1.0–2.3
°Cwith a likelymedian of ~1.5 °C instead of ~3.0 °C.
Also modern paleoclimatic temperature reconstructions showing a larger preindustrial
variability than the hockey-stick shaped temperature reconstructions
developed in early 2000 imply aweaker anthropogenic effect and a stronger
solar contribution to climatic changes. The observed natural oscillations
could be driven by astronomical forcings. The ~9.1 year oscillation appears
to be a combination of long soli–lunar tidal oscillations, while quasi
10–11, 20 and 60 year oscillations are typically found amongmajor solar and
heliospheric oscillations drivenmostly by Jupiter and Saturn movements.
Solar models based on heliospheric oscillations also predict quasi secular
(e.g. ~115 years) andmillennial (e.g. ~983 years) solar oscillations,which
hindcast observed climatic oscillations during the Holocene.
Herein I propose a semi-empirical climate modelmade of six specific astronomical
oscillations as constructors of the natural climate variability spanning
from the decadal to the millennial scales plus a 50% attenuated radiative
warming component deduced from the GCM mean simulation as a measure of the
anthropogenic and volcano contributions to climatic changes. The
semi-empirical model reconstructs the 1850–2013 GST patterns significantly
better than any CMIP5 GCM simulation. Under the same CMIP5 anthropogenic
emission scenarios, themodel projects a possible 2000–2100 average warming
ranging from about 0.3 °C to 1.8 °C. This range is significantly below the original CMIP5GCMensemblemean projections spanning fromabout 1 °C to 4 °C.
Future research should investigate space-climate coupling mechanisms in order to develop more advanced analytical and semiempirical climatemodels. The HadCRUT3 and HadCRUT4, UAHMSU, RSS MSU, GISS and NCDC GST reconstructions and 162 CMIP5 GCM GST simulations from 48 alternative models are analyzed.
herkimer,
Good post. The planet may well cool from this point; we just do not know.
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.
Those words all assume that the future is in full view: global warming will continue, therefore a ‘carbon’ tax is necessary. But those who pay attention to the real world know that presuming the future is exactly what witch doctors do to make a living.
Skeptics look at the scientific evidence, and let the planet — not the IPCC, or scientists’ models — tell us what is happening.
The planet [the ultimate Authority] tells us that global warming has stopped. For seventeen years! It may resume. Or not. But calling it a “pause” is premature. It is a spin word, nothing more.
Congrats, Judith!!!!!!
From an external analysis, the Solar system and our galactic system is what drives the temperature of the Earth. The variability is measured on very long time scales but (as we see from Voyager probes “leaving” our solar system) can also experience step changes in very short time periods. From an internal analysis, our Earth has numerous components that interact with each other to delay, prolong or lag the external forces imposed upon the Earth climate sum. Such small scale Earth systems (in comparison with the much large Solar and galactic) still have significant influence over Earth regional climates but they cannot lead the Solar/galactic forces, they only react and or delay the changes. The Sun has recently entered a period of lower activity, which influences Earth climate in ways that we do not understand. But my bet is that the stall in heating is related to Earth internal systems causing a lag in regional distribution but the stall was led by the Solar activity reduction. This new paper provides new insight into the way chaotic systems on earth are able to propagate variable levels of heat throughout Earth but it in no way explains the global stall in total Earth heat content. If it weren’t for so many warmists touting “missing heat in the bottom of the oceans” then we would be able to admit that the Earth has failed to heat up for fifteen years and now that the Sun has decided to dim down a bit, we’re entering a cooling phase. How much and for how long is the larger question.
And congrats to Marcia Wyatt!!
For those who aren’t aware of this, I believe Marcia was one of Roger Pielke Sr’s students.
Magicjava – Here’s an interesting article on “standing wave” high pressure cells linked to the 18.6 year lunar cycle. That’s one possible physical mechanism.
http://joannenova.com.au/2013/06/can-the-moon-change-our-climate-can-tides-in-the-atmosphere-solve-the-mystery-of-enso/
“The removal of the long-term trend from the data effectively removes the {potential (if it exists at all)} response from long term climate forcing such as anthropogenic greenhouse gases.” (Curry and Wyatt, 2013 – annotated by me)
If Curry and Wyatt do not want to subtly and definitely (albeit weakly) promote AGW, qualifying language such as I added above must be included.
At this point in the game, we are DONE with lukewarm, limp-wristed, hand waving. What is called for from this day forth is bold, loud, robust, assertion of the essentials, e.g., “HUMAN CO2 UP, WARMING STOPPED.”
We are not at a relatively friendly ball game — we are in a WAR for the very survival of Western Civilization (which of course includes Israel and Japan) and FREEDOM.
While scientific integrity, thus, no exaggerating of claims, is always required, we cannot afford to give even the tiniest quarter to the enemy. Not one inch.