Open Mind

Warming, Interrupted?

July 14, 2009 · 74 Comments

A recent post on RealClimate explores a new approach to understanding some of the natural variability in the climate system.


The idea, set forth in a paper by Swanson & Tsonis, is well summarized in the post:


What we find is that when interannual modes of variability in the climate system have what I’ll refer to as an “episode,” shifts in the multi-decadal global mean temperature trend appear to occur. I’ll leave the details of these episodes to interested readers (here and here), as things get pretty technical. It’s sufficient to note that we have an objective criteria for what defines an episode; we aren’t just eyeballing curves. The climate system appears to have had three distinct “episodes” during the 20th century (during the 1910’s, 1940’s, and 1970’s), and all three marked shifts in the trend of the global mean temperature, along with changes in the qualitative character of ENSO variability. We have also found similar types of shifts in a number of model simulations (both forced and unforced) that were run in support of the IPCC AR4 report.

The paper is an update of earlier work (Tsonis, A.A., K.L. Swanson, and S. Kravtsov (2007), A new dynamical mechanism for major climate shifts. Geophys. Res. Lett. 34, doi:10.1029/2007GL030288) positing that in some ways the climate system behaves analogously to a synchronized chaotic dynamical system. In particular it is suggested that when the modes of natural variability of the system (like ENSO, NOA, PDO) synchronize, the coupling between these modes increases. The climate system can then become unstable, entering a new state, and it’s the new state which brings a change in the global mean temperature trend.

Much of the motivation for the hypothesis is the contrast between apparent “discontinuities” in temperature trends, and the continuity of greenhouse-gas and aerosol forcing:


Such discontinuities are difficult to reconcile with the presumed smooth evolution of anthropogenic greenhouse gas and aerosol radiative forcing with respect to time [Hansen et al. 2005]. This suggests that an in internal reorganization of the climate system may underlie such shifts [Zhang et al. 2007].

On the basis of their analysis, the authors suggest that


We hypothesize that the established pre-1998 trend is the true forced warming signal, and that the climate system effectively overshot this signal in response to the 1997/98 El Niño. This overshoot is in the process of radiatively dissipating, and the climate will return to its earlier defined, greenhouse gas-forced warming signal. If this hypothesis is correct, the era of consistent record-breaking global mean temperatures will not resume until roughly 2020.

I have two overriding opinions of this work. My first overall opinion is that I don’t believe it’s correct, for several reasons. One is that the theoretical basis (as outlined in Tsonis et al. 2007) involves an extremely intricate framework of suppositions which I don’t find convincing, and the statistics used to support that work likewise don’t convince me. I don’t believe we have sufficient understanding of the behavior of chaotic dynamical systems to make the transition from the present theoretical framework to a practical real-world analysis of the climate system. Also, the hypothesis uses certain aspects of the HadCRU temperature time series which aren’t shared by the GISS or NCDC time series, so at least in part it’s dependent on the use of a particular data set.

Also, I question the basic supposition that there’s any difficulty at all reconciling known forcing patterns with observed temperature trends. In fact we know that volcanic aerosol forcing and solar forcing go a long way to explain the change in warming trend during the mid-20th century. In fact, even with simple models the known factors do an excellent job matching the last century’s temperature evolution. When we apply full-blown GCMs, the match between hindcasts and observations is nothing short of impressive; it seems to me that no “explanation” of changes in temperature trend is needed at all.

The paper also uses linear trend rates over 7-year intervals to suggest that the most recent lower trend rate (the suggested “plateau”) may indeed match the criteria for a “state change” of the climate, because it doesn’t coincide with a known cause (la Niña or a volcanic explosion). The definition of la Niña used for this claim is “events that exceed 1.5 standard deviations in magnitude based upon on a multivariate ENSO index,” but the MEI (multivariate el Niño Index) defined by Klaus Wolter actually does show a 1.5-sigma event during 2008-2009, so even the most recent “lower trend rate” doesn’t require any unkown explanation.

I’m especially skeptical of the suggestion that we may be beginning an extended “plateau” of temperature change. Using GISS data, the observed variations in trend rate since 1975 (on 7-year or longer time scales) really are statistically indistinguishable from random noise, and the residuals from a straight line fit 1975-present are likewise indistinguishable from noise. Of this I’m sure: although it’s certainly possible that the climate has recently “shifted,” as yet there’s no sound statistical evidence to confirm it (nor does the paper, or the RealClimate post, claim such evidence).

Furthermore, the trend on which they base their projection is from 1979 to 1997 (centered on 1988), which is one of the lowest 18-year trend rates in the recent GISS record. Both earlier and later time spans of the same length indicate greater warming, in particular the time span 1974 to 1992 gives a linear regression trend rate over 0.02 deg.C/yr. And to top it off, the uncertainty in the estimated trend rate using the 1979-1997 span is large enough that the overall trend rate from 1975 to the present is within its confidence interval.

gissrate

My second overriding opinion is that this work is tremendously important. I said earlier that I don’t believe we have sufficient understanding of the behavior of chaotic dynamical systems to make the transition from the present theoretical framework to a practical real-world analysis of the climate system. But without work like this, we never will. If the central hypothesis turns out to be correct, or even if it doesn’t, we may have made great progess toward extending our knowledge of how climate dynamics works. Much of the theoretical underpinning is very appealing, and may be key to future breakthroughs — which almost never happen without someone laying a foundation upon which they’re built. Even if the present work ends up being entirely cast aside, many of its themes may persist and may be an integral part of the next generation of climate dynamics.

As for the implications regarding global warming, the lead author (also the author of the RealClimate post) says it very well:


What do our results have to do with Global Warming, i.e., the century-scale response to greenhouse gas emissions? VERY LITTLE, contrary to claims that others have made on our behalf. Nature (with hopefully some constructive input from humans) will decide the global warming question based upon climate sensitivity, net radiative forcing, and oceanic storage of heat, not on the type of multi-decadal time scale variability we are discussing here. However, this apparent impulsive behavior explicitly highlights the fact that humanity is poking a complex, nonlinear system with GHG forcing – and that there are no guarantees to how the climate may respond.

Categories: Global Warming
Tagged:

74 responses so far ↓

  • Thomas Lee Elifritz // July 14, 2009 at 1:39 am | Reply

    On the curve eyeballing front, certainly something did happen in the 1996 to 1998 timeframe, you can see it in the satellite sea level data and in the arctic ice anomalies. I don’t believe it foreshadows anything multi-decadal, but rather ominously it looks to me to be multi-year. By 1998 a dramatic change was already evident in the erosional behavior of low lying Bahamian beaches, which I believe is directly traceable to the change in thermal behavior of the oceans. Time will tell if decadal oscillations are irrelevant now, but I believe they are, and a new faster oscillation is now evident.

  • Jim Galasyn // July 14, 2009 at 1:55 am | Reply

    Tamino says, quite reasonably, “I don’t believe we have sufficient understanding of the behavior of chaotic dynamical systems to make the transition from the present theoretical framework to a practical real-world analysis of the climate system.”

    We may be a bit further along in understanding the nonlinear dynamics of the climate system than this suggests. I was very impressed with Barry Saltzman’s work, e.g., http://www.agu.org/pubs/crossref/1994/94PA02289.shtml

    Saltzman, B., and M. Verbitsky (1994), Late Pleistocene Climatic Trajectory in the Phase Space of Global Ice, Ocean State, and CO2: Observations and Theory, Paleoceanography, 9(6), 767–779.

    And his subsequent book:

    Dynamical Paleoclimatology: Generalized Theory of Global Climate Change

  • Carl Wolk // July 14, 2009 at 2:25 am | Reply

    To understand modern climate change, we must understand the timing and nature of the recent rise in temperature. To do this, we must to the source – SST, and we must look beyond the global average. People talk of “global warming” and “global cooling,” when in reality, temperature can trend in opposite directions in different regions, with one trend dominating in the global average. For example, the concept of global cooling from 1945 to 1975 is completely false. SST were essentially flat, globally, with some regions rising in temperature and other regions falling.

    Besides looking regionally, one must also be aware of ENSO. ENSO introduces noise into the SST record; it masks step-changes. It is fairly easy to correct for the immediate, noisy effects of ENSO, and one must do so to understand the underlying behavior of SST.

    Swanson fails to do any of this, but he does accidentily notice the step-change associated with the 1997/8 El Nino.

    Swanson is close to the truth. The fact is that global SST (since 1975) has been dominated by the long-term effects of the 1976, 1986/7, and 1997/8 in the North Atlantic, NW Pacific, S Pacific, and Indian Oceans.

    Something about these events must have been radiative. I’ve got some ideas, but I have failed to determine exactly how the mechanism might work. SW radiation data would help, but I don’t have the programs necessary to access this data. Anyone have any reccomendations?

    I’ve replied to Swanson’s post, here:
    http://climatechange1.wordpress.com/2009/07/13/swansons-not-so-novel-post-at-realclimate/

  • Joel Shore // July 14, 2009 at 2:37 am | Reply

    Glad to see you weigh in on this, Tamino. I am also skeptical that there might not really be anything to explain. It is always very tempting for us humans to see patterns in what is essentially random noise. I guess the next few years should give us a better indication of whether there really is anything to explain or not.

    I was quite curious about that ~0.10 C / decade trend that they found from 1979 to 1997, so it is interesting to see that this is pretty much the lowest possible trend one can come up with in any interval of that length with a starting year after ~1970.

  • Andrew // July 14, 2009 at 4:03 am | Reply

    I asked this question on real climate and nobody bit. How much do we know about ocean heat storage? Is the rate of heat transfer from surface waters to deep waters bounded by physics robustly enough to preclude changes in ocean circulation that would cause global temperatures to decline or stay steady for decades or even centuries? Do we know enough to know this? Also, did the 1998 El Nino raise global temps by causing a slow down in the rate heat is stored in the oceans or was previously stored heat actually released. I.E. could the ocean one day burp up enough heat to cook us all?

  • Hank Roberts // July 14, 2009 at 5:11 am | Reply

    We certainly don’ t know enough, we have very little long time series information.

    Look how many of these itty bitty excerpts mention sparse data and little known areas:
    http://scholar.google.com/scholar?q=1998+%22El+Nino%22+ocean+heat

    We’re not like ‘blind men describing the elephant’ — we’re like fleas describing some kind of angry beast we understand very incompletely, but know we are provoking.

  • Hank Roberts // July 14, 2009 at 5:17 am | Reply

    Also (remember I’m an amateur reader, at best I’m picking up possible _examples_ of what might be interesting and relevant from the grab bag available. I’m not pointing to anything that’s certain to include knowledgeable answers), just what suggests that something is known:

    Re-examination of the Observed Decadal Variability of Earth Radiation
    Budget using Altitude-corrected ERBE/ERBS Nonscanner WFOV Data

    Takmeng Wong
    Bruce A. Wielicki
    Robert B. Lee, III
    G. Louis Smith
    Kathryn A. Bush
    Josh K. Willis

    Revised for the Journal of Climate
    November 2005

    http://asd-www.larc.nasa.gov/~tak/wong/f20m.pdf

    This paper gives an update on the observed decadal variability of Earth Radiation
    Budget using the latest altitude-corrected Earth Radiation Budget Experiment
    (ERBE)/Earth Radiation Budget Satellite (ERBS) Nonscanner Wide Field of View
    (WFOV) instrument Edition3 dataset. …

    “… the ERBS Nonscanner observed decadal changes in tropical mean LW, SW, and net radiation between the 1980s
    and the 1990s now stand at 0.7/-2.1/1.4 Wm-2, respectively, which are similar to the
    observed decadal changes in the HIRS Pathfinder OLR and the ISCCP FD record; but
    disagree with the AVHRR Pathfinder ERB record. Furthermore, the observed inter-
    annual variability of near-global ERBS WFOV Edition3_Rev1 net radiation is found to
    be remarkably consistent with the latest ocean heat storage record for the overlapping
    time period of 1993 to 1999. Both data sets show variations of roughly 1.5 Wm-2 in
    planetary net heat balance during the 1990s. …”

  • mspelto // July 14, 2009 at 12:23 pm | Reply

    Andrew I do not see how the short term 1998 super el nino could add sufficient surplus radiative heat to be stored by the ocean to then take a decade to dissipate that heat. I agree with Tamino the coupling idea and methods seems sound but the temperture record and the types of climate indices limited. This suggests the output is not robust. For example the Arctic Oscillatioin is not used but the PDO and NP both focussed in the North Pacific are. That coupling is critical was brought home to me in deriving a mass balance forecast model, that relies princiipally of the magnitude and the coupling of ENSO and PDO http://www.nichols.edu/departments/glacier/mass%20balance%20forecasting.htm

  • george // July 14, 2009 at 1:29 pm | Reply

    Joel Shore

    It is always very tempting for us humans to see patterns in what is essentially random noise. “

    I agree that appearances can be deceiving, but it seems to me that it is important to distinguish between the event that “drives” the climate system and the “response” of the system to that event (in this case, the change in global temperature).

    The event might be random, but the response might have a pattern.

    There are lots of examples from physics and engineering (one of the simplest being the mass-spring-dashpot system, for example) where the impulse that “jars” the system might be essentially random, but the transient response quite “regular.”

    So, even if phenomena like El Nino are actually “random” events, the response of the climate system to a large El Nino (or other similar temperature influencing event) might nonetheless have some “pattern” to it.

  • Timothy Chase // July 14, 2009 at 2:14 pm | Reply

    Andrew wrote:

    I asked this question on real climate and nobody bit…

    That looks more like four essay type questions. At one point you even ask, “Do we know enough to know this?” Sounds a bit like you are getting ready to pull a Descartes and start staring at your hand. And maybe people don’t feel quite like launching into a philosophic discussion. (Well, I might not mind quite so much — having been a philosophy major and all — in fact I wrote an eighty page paper on Descartes’ Six Meditations’ just for the heck of it a little over a decade ago — but my time is quite limited at this point.)

    We don’t know everything. We can’t claim to have excluded things we know absolutely nothing about, e.g., aliens siphoning off heat and beaming it out into space — while powering their bowling alleys. But we do know some things.

    We have well-supported theories of gravitation, heat transfer, radiation transfer, fluid motion, and so on. This permits us to model the behavior of the ocean and even the earth’s climate system, and then we have instruments that permit us to test this modeling, instruments which include buoys, deep sea robots, cables for measuring ocean speed, satellites and so on. And we can test our models against the paleoclimate record.

    And we also have the scientific method. It doesn’t really permit one to “test theories” by simply proposing that there might be something entirely unknown that hasn’t been accounted, and when asked what it might be, say, “Well, something.” Models and theories get tested all the time. And there is much that different climate models agree upon, and that is increasing as these models take more of the physics which is involved into account.

    However, if you have other specific tests you can suggest, tests of conclusions that may be reasonably drawn from a given model, feel free to propose them. If you have your own testable model you might write about that as well. And perhaps you may contribute something which others will find of value as we engage in this ongoing dialogue between humanity and reality that we call “empirical science.”

    • Ron D. // July 15, 2009 at 4:59 pm | Reply

      Timothy, I’m sure you’ll have an appreciation for the possibility that today’s great AGW debate may, to some degree, be the result of ignoring the big picture lessons of Descartes’ invention of analytic geometry and his subsequent use of clear and distinct ideas of mathematical reasoning as a method to resolve all questions (contrary to the then prevailing Aristotelian view). Last I read the split Descartes’ method created between mind and matter is still unresolved, and his proposal to use the pineal gland as the connecting point between the physical and the mental worlds wasn’t a great success. So considering you must have a well beyond average fluency in the Cartesian issue (and please believe me, I’m not trying to be snarky or smart assy here) I must ask if you’ve mulled on Rene’s bifurcation of reality being replayed in the current insistence on a split between weather (matter) and climate (mind), as well as the pineal being an analog of a climate model i.e. a device to turn mathematically created mental weather into actual physical sensory weather? If, and I’m sure you would agree, there is at least a plausible degree of similarity here then the ultimate success of the use of climate models to provide knowledge of future weather might be the equivalent of Descartes’ knowledge about the future of philosophical development that resulted from his method. Thanks in advance if you decide to respond.

      Ron D.

  • dhogaza // July 14, 2009 at 4:21 pm | Reply

    As usually, Watts manages to entirely miss the point both of the paper …

    and of the fact that the real climate post was a guest post to allow Swanson the opportunity to present his hypothesis and paper results in a very visible public forum.

  • dhogaza // July 14, 2009 at 4:25 pm | Reply

    Actually, it’s Peilke The Lesser” who made the post referenced by WUWT, and makes no effort to point out that it’s a post by one of the authors of Swanson and Tsonis rather than the opinion of the RC team.

    Pffft.

  • Andy // July 14, 2009 at 9:13 pm | Reply

    Yeah, this is way beyond me. Aerosol affects are still not well known and I wondered if potential changes in ocean circulation also kept climate modelers up at night. How would one test possible outcomes? I guess by seeing how sensitive climate models are to increasing or decreasing global wind velocities and ocean circulation volumes by say 25%? If such a massive change has little effect on atmospheric temps then there you go. No need for the lunesta anymore.

    Why do I ask? I’m a poor slob armed with nothing more than a masters in ecology who has to try and reach out beyond what can be gleaned from the normal news outlets and then inform my supervisors about what the heck is going on with all this global warming stuff so they can accomplish reasonable long term planning in a coastal environment that’s already on the edge of a desert. A typical conversation: “Is this global warming for real? Didn’t I just see on Fox News last night that global warming has stopped and won’t start up for another 20 years? Oh yea, those global warming freaks are making excuses now. And hey, it’s been freezing cold up north this year so why’s that if the earth is getting warmer. I heard it snowed in Germany this past June. And now you what? You don’t want us to rebuild this on the beach because the sea is getting deeper?” Etc, Etc, Etc.

    I’ve go to go cry in my hankie now.

    Thanks for the google Hank Roberts. I’ll start reading.

  • MikeN // July 14, 2009 at 9:35 pm | Reply

    Tamino, aren’t you of the opinion that there was a ‘climate shift’ in 1975? That is right around the time they are saying.

    [Response: I'm of the opinion that the warming trend changed around 1975. By "climate shift" they're referring to a chaotic dynamical system entering a new regime -- which is a different issue.]

  • sidd // July 14, 2009 at 10:51 pm | Reply

    Andrew writes: re Ocean Heat Content

    OHC reveals itself in sea level rise.

  • David B. Benson // July 15, 2009 at 12:01 am | Reply

    Jim Galasyn // July 14, 2009 at 1:55 am — The paper by Barry Saltzman and his coauther is behind a paywall for me. Could you say a bit about the dynamical system they used?

  • Timothy Chase // July 15, 2009 at 12:33 am | Reply

    Tamino wrote inline:

    I’m of the opinion that the warming trend changed around 1975. By “climate shift” they’re referring to a chaotic dynamical system entering a new regime — which is a different issue.

    I’m not sure how different it is. And I am not sure how much sense I have been making. But in my view the forcings are principally projected onto the modes of natural variability (e.g., Corti et al., 1999), and this gives rise to a complementarity of sorts in which the view in terms of chaotic climate mode networks that exist within different phase space regimes and the view in terms of a system subject to forcings and feedbacks may be two different perspectives on the same phenomena rather than two different processes that compete in terms of relative importance.

    Climate shifts are stepwise — you have pointed this out in the past with respect to hurricanes. And it would make sense if other aspects of the climate system — such as the average rate of warming — were stepwise as well.

    However, the question at that point is how sensitive the stepwise shifts are to changes in the forcing — how efficient they are in homing in on a roughly linear trend that results from the forcing. And in this context, the synchronicity at the time of the transition (which implies that the system is acting as a coherent whole) and then the fluctuations or “variability” that exists in the regime that follows might very well act as engines of an exploratory process by which the system is able to quickly home in on that trend.

  • Deep Climate // July 15, 2009 at 1:32 am | Reply

    dhogaza,
    Thanks (I think) for pointing out RP jr’s weird take on this. I asked RP to clarify that the RC post was a guest post by Swanson.

    I also suggested that his readers come here for a discussion of the issues with the paper.

  • dhogaza // July 15, 2009 at 4:56 am | Reply

    Deep Climate – nice post over at RP jr’s blog. You’ll be ignored, I’m sure, which is why I didn’t bother posting (figuring out an ID that would take there, etc).

    Anyway, good effort. The RPs drift further from science as politics drift further from what they’d like to see. They’re putting their reputations on the line hoping to help forestall action. Well, that’s not new, but since we have a bill (no matter how weak) through the House, with reasonable prospects for the Senate, apparently they’ve (RP sr, RP jr) to blow up whatever scientific credibility they’ve had left.

    Good on them. Much better to have them so transparent and obvious rather than hiding behind the veil of “we just talk about science” crap.

  • Riccardo // July 15, 2009 at 9:12 am | Reply

    The idea of mode resonance is intriguing and i agree with Tamino’s second opinion on the importance this study may have.
    What i find hard to immagine is the picture of a sort of bistable climate system in which whenever there is a resonance the climate system switches. But maybe my reasoning is too “linear”.

  • vibenna // July 15, 2009 at 10:39 am | Reply

    Interesting. I recall getting roundly abused on this blog when I tried to engage with these issues. Turns out my thinking ain’t so different. Here’s what I said on 8 February.

    http://vibenna.wordpress.com/2009/02/08/global-warming-a-skeptic-recants-part-two/

  • Timothy Chase // July 15, 2009 at 3:01 pm | Reply

    vibenna wrote:

    Interesting. I recall getting roundly abused on this blog when I tried to engage with these issues. Turns out my thinking ain’t so different. Here’s what I said on 8 February.

    http://vibenna.wordpress.com/2009/02/08/global-warming-a-skeptic-recants-part-two/

    Well, part of the problem is that you introduced yourself as a skeptic in that particular essay, and early into the essay it at least sounds like you might be arguing that climate modes are some sort of alternative explanation for global warming. However, we know for example that as you increase the opacity of the atmosphere to thermal radiation things have got to warm up until a balance between the rate at which energy leaves the system is equal to the rate at which it enters. Climate modes won’t change that.

    But looking at the rest of your essay I can see that what you are arguing for is a stepwise evolution of the climate system of sorts, or at least one in which the states of climate oscillations determine to some extent the rate at which the climate system warms in the short-run (which in this context means the scale of decades), but not the long-run — although you would still apparently argue for a lower rate of warming than say the IPCC.

    However, at the same time, whatever “theorizing” you or I might do isn’t really that comparable to what is actually done by climatologists or even what statisticians do when critiquing the statistical arguments that climatologists do. I wouldn’t say that we are simply shooting the breeze, but it is somewhere in between. If either you or I presented ourselves as heralding the next revolution in climate science we would probably get what we deserve: being treated as crackpot substitutes for clay pigeons at the shooting range.

  • Timothy Chase // July 15, 2009 at 3:19 pm | Reply

    PS to vibenna

    Science elicits curiosity, and with curiosity one tries to understand oftentimes by “playing” with ideas, trying to make sense of reality of the theories proposed by others and how everything fits together. This is a good thing.

    However, climatology has been and still is the target of a large disinformation campaign by the fossil fuel industry — even though in the long run this will in all likelihood cost a great many lives. As such people of good will who see this happening naturally want to rush to the defense of science and climatology.

    But no doubt we can get a little trigger-happy. Sometimes we might mistake the products of natural curiosity for part of the disinformation campaign, and this may lead to what in times of war would be called “collateral damage.”

  • Timothy Chase // July 15, 2009 at 3:42 pm | Reply

    PS PS to vibenna

    In the comments it looks like Gareth had a pretty good handle on what you were arguing.

    Take care.

  • sidd // July 15, 2009 at 3:48 pm | Reply

    Mr. Galasyn, thanx for the reference to Saltzman’s work,.

    Mr. Benson, let me try an summarize for you. Saltzman et al. use proxies for ocean state(theta), ice mass(psi) and CO2 concentrations (mu) and graph them both in a 3D space as well as their projections in the theta-psi, theta-mu and psi-mu planes. The results are a little messy but reveal that there is a phase lag between mu and psi and mu and theta. But there is none between psi and theta.

    Some smoothing produces beautiful graphs which I have reproduced at
    http://membrane.com/sidd/7a-b.png
    and http://membrane.com/sidd/7c.png

    clearly showing the 100KYr oscillation.

    Very pretty. (the smoothing suppresses the hi-frequency behaviour). The states lie along a climate attractor which circles an unstable ‘hole’ in the phase space.

    They go on to construct a system of 3 coupled oscillators, admitting of a closed form solution and reproduce many of the features of the data, including the propensity for the system to sit in the cold, glacial state. The model also indicates the the carbon cycle instability drives the oscillation while Milankovitch forcing sets the phase.

    I am sure that I have missed many important points, but hopefully you get the gist…

    I quite like this paper, and I would appreciate pointers to more modern work along the same lines, using newer data over much longer timescales than were used in the Saltzman paper.

    sidd

  • Hank Roberts // July 15, 2009 at 5:34 pm | Reply

    Vibenna, they say there, in the bit Tamino quotes above:

    “… note that we have an objective criteria for what defines an episode; we aren’t just eyeballing curves. ”

    What criteria were you using?

  • vibenna // July 15, 2009 at 10:39 pm | Reply

    Timothy, thanks for your thoughtful comments.

    Hank – I accepted the distinction made at http://www.intellicast.com/Community/Content.aspx?ref=rss&a=151 between warm mode and cool mode. I also found this convincing because the El-Ninos since 2002 had relatively less intensity than previous El-Ninos, as predicted by the hypothesis that the PDO modulates El-Nino / La Ninas.

    So I’m looking a more macro level – for confirmatory evidence of predicted consequences – that at the micro level of detailed statistics. There are of course other competing explanations, but I found the set of hypotheses I adopted were good at both explaining the past and predicting the future.

    The other part of my prediction is that when the PDO flips, warming will re-start at double the centenniel average.

    And I guess the key take out is that climate forecasts need to take account of heterogeneity in these warm/cold events – that is, they aren’t evenly distributed, so estimates over a particular time period will be biased by the random inclusion of more warm or more cold events.

  • Alex Luta // July 15, 2009 at 11:06 pm | Reply

    Tamino,

    after spending some good two hours reading your blog, i have to thank you for restoring my confidence that i am not wasting my life doing research on the politics of climate change. :)

    One small question, though, asked in good faith: Search as hard as i might, i have been unable to find a reference in your blog as to who you are and what kind of work you do? Do you not share that information with your readership?

  • Timothy Chase // July 16, 2009 at 2:13 pm | Reply

    Alex Luta wrote:

    after spending some good two hours reading your blog, i have to thank you for restoring my confidence that i am not wasting my life doing research on the politics of climate change. :)

    I and others can probably dig a few things up for you such as the connections between various front organizations and the fossil fuel industry, libertarian organizations, organizations involved in the defense of cigarettes, and the major financiers of the religious right’s attempt to take over the Republican Party. There is actually a lot of documentation (including PDFs available online of Exxon’s tax returns listing the amounts and recipients of its charitable contributions), but much of it is scattered. Let us know if you are interested. However, simply as a matter of human psychology and every individual in one way or another regarding their time as limited, it might help motivate people if you give them some idea of your intended goal.

    Alex Luta wrote:

    One small question, though, asked in good faith: Search as hard as i might, i have been unable to find a reference in your blog as to who you are and what kind of work you do? Do you not share that information with your readership?

    Tamino is a professional statistician whose work normally focuses on issues involving astronomy if I remember correctly. However, he has coauthored papers with the professional climatologists in charge of Real Climate. So clearly they (and some others around here, including Ian Jolliffe, a prominent theoretician in the field of statistics) know who he is. However, for at least a couple of reasons (related to work and health) he has chosen to use his moniker.

  • Timothy Chase // July 16, 2009 at 2:30 pm | Reply

    PS

    I believe it would be a good idea to make whatever documentation (preferably by means of links and descriptions) available to Mr. Luta. Either in the Open Thread, a new thread devoted to the politics of climate change if Tamino is interested in creating one, etc.. I will put up some material tomorrow. Today is a little busy, but tomorrow will be less so.

  • Paul Middents // July 16, 2009 at 3:54 pm | Reply

    James Annan has a post on this topic today.

    http://julesandjames.blogspot.com/2009/07/yet-more-on-decadal-prediction-and.html

    James is sceptical of the predictive ability of Swanson and Tsonis latest work. He particularly questions the flat red line in the figure posted at RC which Swanson refers to as the post 1998 plateau.

  • David B. Benson // July 16, 2009 at 10:34 pm | Reply

    sidd // July 15, 2009 at 3:48 pm — Thank you! Turns out I’ve read his book.

    Much of modern climatology is focused on the bottum-up GCM approach. There are some other papers, for example
    E. Tziperman, M. E. Raymo, P. Huybers, C. Wunsch, 2006. Consequences of pacing the Pleistocene 100 kyr ice ages by non linear phase locking to Milankovitch forcing (pdf), Paleoceanography
    available from
    http://puddle.mit.edu/~cwunsch/

  • Dan Satterfield // July 17, 2009 at 6:49 am | Reply

    The RC article left a bad taste in my mouth as well.
    What a great discussion here about it. Much better than the tripe on some of the blogs. Tamino, you are either exercising good editorial control or just lucky!

    As for Watts et al. Last weeks response from NOAA about his Heartland Inst. PR stunt gave me the best laugh in awhile.

  • dan // July 17, 2009 at 10:14 pm | Reply

    Looks like global surface anomaly maps are being released on a monthly and even weekly basis here by the Japanese Meterological Agency:

    http://ds.data.jma.go.jp/tcc/tcc/products/climate/monthly.html

    You’ll have to pick “temperature anomaly” from the combo box to see it. Bear in mind the anomaly maps use the baseline 1971-2000.

  • ab // July 18, 2009 at 10:18 am | Reply

    Tamino you responded to MikeN (July 14; 9:35) „ I’m of the opinion that the warming trend changed around 1975.“, which we comment as follows:
    Did a shift occurred in app. 1975, or did a warming trend only returned, which had been interrupted around 1940? The last Century experienced presumably only two shifts. There was the marked shifts in the late 1910s (the early Arctic warming 1919-1939 : Here) which could have been initiated (or partly caused) by the Great World War (1914-1918) http://www.arctic-warming.com/, that was followed by the cooling between 1940 and the 1970s, would have defiantly not have occurred in the way it did, if the naval war activities in Europe and around the world during the World War II had not taken place, as thoroughly explained at: http://www.seaclimate.com/ .
    In a recent paper ( Extreme Winter 1939/40 – PDF) it has been demonstrated, that the extreme winter 1939/40 in Europe did not came from nowhere, but has had its cause in the immense naval war activities since 1st September 1939. It became the coldest winter in Central Europe for more than 100 years; details at: http://www.oceanclimate.de/
    If Kyle Swanson et al. had proved that the cold Europe winters 1939-1942 had nothing to do with WWII, their claim would be more credible.

  • Hank Roberts // July 18, 2009 at 4:35 pm | Reply

    Oh, ‘ab’ is back. Well, I’m a skeptic on this.

    Ab’s one of the userids often seen pointing to the book and websites arguing that the oil spilled during naval encouters during the world wars changed the climate. I’ve pointed out to several of their avatars the published estimates of total natural petroleum leaking into the oceans (somewhere between 10x and 100x the total spilled in the war years by naval action, annually).

    You’ll find their arguments posted under a lot of websites; the ones I know of are oceanclimate.de, seaclimate.com, arctic-warming.com, warchangesclimate.com, bernaerts-sealaw.com, arctic-heats-up.com, whatisclimate.com, 1-ocean-1-climate.com, 1-okeah-1klimat.com, bernaerts-guide.de, bernaerts-guide-russian.de, 1ocean-1system.de, ozeankilma.de

    I’m sure there are others.

    If they ever, anywhere, address the total amount of petroleum spilled compared to current estimates of natural leaks of petroleum per year, it might be interesting to see the numbers.

    The guy’s certainly convinced and passionate. If there’s any science supporting it, not written by the guy with the websites, citations to journals would be welcome. Pointers to the multiple websites, not.

  • ab // July 18, 2009 at 6:33 pm | Reply

    #Hank Roberts
    Its fine that you are a skeptics of a thesis: „that the oil spilled during naval encounters during the world wars changed the climate”. I fully agree as this would be utterly nonsense. The naval war thesis as discussed in a number of cited websites is based on a complete different approach concerning ocean and climate matters, and has nothing to do with oil pollution or any other pollution.
    ABSOLUTE NOTHING!!
    The matter is about changing the temperature and salinity structure of the sea surface over a considerable depths.
    Best regards ab

  • Kevin McKinney // July 19, 2009 at 12:09 am | Reply

    “sea surface over a considerable depths?”

    I think you just lost me. . .

  • Hank Roberts // July 19, 2009 at 2:04 am | Reply

    ‘ab’ — the replies people make to you consistently on many blogs always repeat the basic objections; lack of citation, lack of recognition of physics. Everyone gives you top ratings for persistence and staying on your message.

    Here for example:
    http://www.scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=13&idContribution=1954

    Starting with:
    —-excerpt follows—-

    [7] Comment by thx1138 – 17 May, 2008 10:06 am

    The Nature article: NATURE 453, 84-88 (1 May 2008), quoted by ArndB DOES NOT call into question the effects of greenhouse gases, of which CO2 is just one, but a very significant one. The source of the anomalous warmth is predominantly from the greenhouse effect and the excess CO2 in the atmosphere….”

    And going on to say

    “… My very simplistic analysis:
    I have a feeling that the enormous growth in world-wide shipping traffic, in recent decades, must be vastly greater than the short-lived WW2 shipping movements. Modern shipping includes container ships and tankers that are much larger and more numerous than typical WW2 ships and nuclear submarines that travel at high speed when submerged.

    If as you maintain, shipping induced ocean mixing were significant as a cooling effect, this would imply that the current true magnitude of warming from all sources is much greater than reflected in increased temperatures. But that would have been noticed, since AFAICT, it hasn’t, I strongly suspect your idea is seriously flawed. Is this why it hasn’t been published in a relevant reputable ISI peer-reviewed journal?

    I’m sorry if I’ve dismissed your life’s work in a paragraph, but I want to see citations of peer-reviewed science, in a relevant respectable journal, or I’ll consider it’s just junk! No websites, please!”

    —- end quote—

  • ab // July 19, 2009 at 10:26 am | Reply

    #Hank Roberts
    One of my replies to “thx1138” had actually been questions, which presumably would find a reasonable answer if paying more attention to the naval war thesis as explained and discussed in articles, books and websites.
    >>QUOTE> from Scitizen>>
    [11] Comment by ArndB – 24 May, 2008 07:21 pm
    # No 7; Comment by thx1138 – 17 May, 2008 10:06 am
    __What caused the sudden arctic warming in winter 1918/19 lasting winter 1939?
    __What caused the extreme war winter 1939/40 ?
    __What caused the global cooling from 1940 – ca.1970?
    __ Why does the UNFCCC not define CLIMATE”?
    You know the answers?
    Maybe J.D. Woods did: Nevertheless, the upper ocean holds the key to climate prediction”.
    REF: “The upper ocean and sea-air interaction in global climate”, in: John T. Houghton (ed), 1984,
    The Global Climate, Cambridge, p.141, 142.
    http://www.scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=13&idContribution=1954
    >>UNQUOTE>>

    Kindly take note that my work is based on the understanding that
    CLIMATE IS THE CONTINUATION OF THE OCEAN BY OTHER MEANS
    _____(see: Letter to the Editor of „NATURE“, 1992; “Climate Change” 360, 26 Nov. 1992, p. 292, http://www.whatisclimate.com/1992-nature.html ,
    _____and other articles, for example: “Legal means for understanding the marine and climate change issue”, in: Thomas A. Mensah (ed), “Ocean Governance: Strategies and Approaches for the 21st Century”, Proceedings The Law of the Sea Institute, 28th Conference, Hawaii, 1994, pp. 156 – 180, -see here: http://www.oceanclimate.de/English/index.html )

    The core subject of my investigation are the three ice-age-style war winters 1939-1942 in Northern Europe. If simple physics and the developments of the winter condition are recognised, any due analysis will eventually require to take the naval war activities into consideration. Due to the sudden arrival of huge naval armadas and their various activities in the only modestly deep North- and Baltic Sea, any stored heat during the summer period is earlier released than usually, allowing continental and polar air to prevail. This three war winters in Europe are thoroughly explained over 200 pages in the book: ‘Climate Change and Naval War”, Victoria/CA, 2005, with a List of References p.313-326. (also available at: http://www.seaclimate.com/ ) The subsequent war winters (1943-1944) were different in so far as since the ambush on Pearl Harbour on 7th December 1942 the naval war went global. For this reason it seems not to far fetched to ask whether the global cooling since the early 1940s stands in any connection with the naval war during that time. But raising and discussing this question would be easier if the reason for the extreme war winters 1939/40, 1940/41, and 1941/42 is settled.

    For the same reason it would make little sense nowadays to discuss impact of the world merchant navy on the ocean, seas, and climate since it changed from sail to machine vessels since about 1850. This fleet has increased in ship number and ship size constantly over the years, while the naval activities during WWII arrived very suddenly on the scene. This situation and the fact that one can confine the matter in one case (of the questions cited above) to three war winters, provide a unique opportunity to investigate the matter, as done for the first war winter one year ago “A Large-Scale Experiment with Climate – The Extreme Winter of 1939/40 and Climate Research – “, 2008,
    In PDF: http://www.oceanclimate.de/A_Large_Scale_Experiment_with_Climate/A_Large_Scale_Experiment_with_Climate.pdf
    In WORD at: http://www.oceanclimate.de/ (left column)
    Efforts to discuss the influence of the oceans on climate due to human activities will continue.

  • Hank Roberts // July 19, 2009 at 3:34 pm | Reply

    Look for numbers. You can get the numbers behind the shipping charts. Do something with available information instead of simply reposting the same stuff year after year, under one of many userids, on blog after blog!

    The economy runs other experiments all the time. Shipping collapsed during the last depression and during the current one.

    Correlate this over time.
    http://www.investmenttools.com/futures/bdi_baltic_dry_index.htm

  • drawp // July 20, 2009 at 12:04 am | Reply

    Re: ab’s list
    Here’s another question to add to the list.
    What happened to the “nuclear winter” scenario predicted by Carl Sagan and others if Saddam Hussein fired the oil fields in the first gulf war of 1991?
    He set them afire and as far as I know the weather was unremarkable despite huge clouds that covered much of Asia. Perhaps the earth is not in such a delicate balance.

  • JCH // July 20, 2009 at 12:24 am | Reply

    Yes, gobs of climatologists agreed with Sagan.

    Well, okay, maybe one?
    The discussion was based upon the idea of a long war in which nobody would be able to get in an extinguish the fires at free flowing wells. The war was very short and many of the wells were not as free flowing as assumed.

  • David B. Benson // July 20, 2009 at 1:34 am | Reply

    I read the quite short “Detecting low frequency oscillations of the pacific ocean by the ocean upper layer temperature data” by Mingquiang Fang et al. which appeared in some IEEE publication in 2003 and is probably behind a paywall, but try
    fmq@orsi.ouc.edu.cn

    The relevance here is they established, by typical FFT methods, the existence of pronounced low frequency oscillations in heat content using the 45+ years of instrumental data. Naturally, ENSO frequencies show up well but the interesting aspect is noticable power at a periods of about 14 (horizontal) and 27 (vertcal) years. Now the instrumental record is too short to detect power at a period of around 60 years but this possiblity remains open.

    The short paper hints at the possiblity that these low frequency oscillations are energized by variations in TSI (although they forgot to take volcanic and other aerosols into account, perhaps). Still, this aspect seems to agree with a recent paper from NCAR discussed popularly here:
    http://www.sciencedaily.com/releases/2009/07/090716113358.htm
    (one which seems to have taken the denialosphere by storm, I fear; why am I not surprised?)

  • Kevin McKinney // July 20, 2009 at 12:24 pm | Reply

    David, a naive question perhaps, but what do you mean by (horizontal) and (vertical) years?

  • David B. Benson // July 20, 2009 at 8:22 pm | Reply

    Kevin McKinney // July 20, 2009 at 12:24 pm — Sorry, I was too brief. One figure refers to horizontal redistribution of heat and the other a vertical redistributiion.

  • David B. Benson // July 20, 2009 at 10:46 pm | Reply

    Poster george, on another thread, inquired about ringing in the climate. From the Mingquiang Fang et al. paper I referenced above, we have the following periodic, low frequency, vertical behavior of heat in the upper (400 m) Pacific Ocean:
    27.4, 8.1, 5, 3.8, 2.5 year periods.

    I’ve looked at several papers regarding the 3.8 year period signal. From these, it is clear that this is a free vibrational mode of the North Pacific (Rossby/Kelvin wave) with teleconnections to the Atlantic. There is enough energy from surface waves and tides to keep this mode activated, compensating for the inevitable losses at reflective boundaries.

    The 5 year period power band is wide and high in the horizontal components of the heat signal. This is ENSO. The 2.5 year power might be a form of ringing following an ENSO change, that is, a forced vibration mode rather than a free one. Either way, there is little power in that period band.

    The 8.1 year power band is also quite weak. I question whether or not the 27.4 year signal is but an artifact of the algorithm employed with only 47 years of data.

  • David B. Benson // July 21, 2009 at 12:37 am | Reply

    I posted earlier a link to an article about the recent NCAR study stating a connection between the solar sunspot cycle and mini-ENSO phenomena in the Pacific. Now NOAA (as I recall) states that the average sunspot cyle is 10.448 years long. Looking again at the Mingquiang Fang et al. paper for periods near that one finds
    Zonal (a horizontal component): 12.9 years; maximum power for zonal;
    Meridional (a horizontal component): 13.8 years; maximum power for meridional;
    Vertical: nothing interpretable (which is quite surprising to me);
    Mean temperature: 10.7 years; second most powerful for mean temperature.

    Now the data used was the 47 years from 1955 to 2001 CE. That is over 4 complete sun cycles of average length and I suppose those were fairly average in length and irradiance change. During these 47 years there were several fairly major volcano erruptions; taking that into account this 2003 paper seems to support the NCAR study, except for the anomalous vertical temperature power spectral density.

  • David B. Benson // July 22, 2009 at 10:25 pm | Reply

    Being but an amateur at this, I make mistakes. In particular, the papers on ocean Rossby waves I’ve been perusing mention winds as the energy source for these nonlinear body waves.

    Going through Toshihiro Sakamoto’s “Low frequency variability of a two layer ocean forced by periodic winds”, Eartth Planets Space 58(2006)
    http://www.terrapub.co.jp/journals/EPS/pdf/2006/5809/58091203.pdf
    we see many n-cycles , that is, (1/n)-subharmonics, in Sakamoto’s 1000 km by 1000 km flat bottomed ocean. See especially figures 4 and 5.

    Interestingly, another paper mentions that Rossby waves appear to travel a bit faster in the actual Pacific Ocean than in model studies such as Sakamoto’s (where in difficulties of doing the numercal intergrations required for modeling Rossby wave propagation are evident). Taking that into account, the 3.8 year period signal from the Mingquiang Fang et al. paper can be interpreted as the 4-cycle to annual variability, the 5 year period is the 5-cycle and so on.

    The substantial power in the long cycles might be explained by decadal and inter-decadal variablity of gyres, the roughly circular ocean currents. Sakamoto writes “It is also known that the Koroshiro off Japan and its extension show interannual and decadal variations in path, velocity and volume transport.”

    I would naively expect the n-cycles to become less powerful with increasing n; it is approximately what is seen in Sakamoto’s modeling. So the large power found around 12 years and even larger around 25 years is either an artifact of the power spectral analysis in the Mingquiang Fang et al. paper or is pumped somehow from the solar cycle. Having myself having had such troubles with FFT for very low frequencies, I’m inclined to view those low frequencies as contining much less power than the Mingquiang Fang et al. graph indicates. So I now am of the opinion that these oceanic variations are generally masking the mini-ENSO produced by the solar cycle.

    The original reason for considering all this was to relate these other papers to the Swanson & Tsonis, paper. I know believe I have failed but I have certainly managed to learn much more about Rossby waves and something more about the still rather mystereous ENSO.

  • David B. Benson // July 22, 2009 at 11:32 pm | Reply

    Just for completeness, here is the abstract by Gerald A. Meehl and Julie M. Arblaster at NCAR I referred to in comments above:
    http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F2009JCLI2619.1
    The paper is behind a paywall for me so I relied on the ScienceDaily(?) article about the study.

  • David B. Benson // July 23, 2009 at 2:12 am | Reply

    This lecture by David Battisti, “Developing a Theory for ENSO”
    http://www.asp.ucar.edu/colloquium/2000/Lectures/battisti1.html
    is much better than any other I have seen so far on ENSO.

  • Curious // July 23, 2009 at 10:34 am | Reply

    I don’t find any “contact” link, so I suggest here giving some perspective on this new paper (I’ve also suggested it in other couple of blogs):

    Influence of the Southern Oscillation on tropospheric temperature
    McLean, J. D., C. R. de Freitas, and R. M. Carter (2009),
    Geophys. Res., 114, D14104, doi:10.1029/2008JD011637
    http://www.agu.org/pubs/crossref/2009/2008JD011637.shtml

    Reading the abstract, I thought it was about variability alongside the underlying trend (nothing new under the sun), but I’m astonished by its author’s declarations:

    http://www.climatedepot.com/a/2117/New-PeerReviewed-Study-Rocks-Climate-Debate-Nature-not-man-responsible-for-recent-global-warminglittle-or-none-of-late-20th-century-warming-and-cooling-can-be-attributed-to-humans

    http://climaterealists.com/index.php?id=3756

    Are we in front of a new unnoticed and revolutionary paper? Or is it just a cheap trendy way of getting publicity?

    Thanks for your blog.

  • dhogaza // July 23, 2009 at 1:03 pm | Reply

    Are we in front of a new unnoticed and revolutionary paper?

    Two words for you: Bob Carter. He’s a notorious denialist.

    My guess is that Real Climate will take the sword to this paper at some point.

  • Hank Roberts // July 23, 2009 at 3:19 pm | Reply

    So he’s up to five papers now?

    http://www.desmogblog.com/chris-dde-freitas

    … Dr. Chris de Frietas, has a controversial record of past editorial practices … chief editor Hans von Storch and 3 additional editors subsequently resigned … by David Appell in Scientific American, and in a news brief in Nature. …
    http://www.realclimate.org/…/peer-review-a-necessary-but-not-sufficient-condition/

  • dhogaza // July 23, 2009 at 3:39 pm | Reply

    Are we in front of a new unnoticed and revolutionary paper?

    Well, it would seem to assume that the ocean is heating itself, and therefore the atmosphere, rather than the mainstream view that the oceans are warming because of AGW.

    Somehow I don’t think the mainstream’s going to find this argument very convincing.

  • Curious // July 23, 2009 at 4:18 pm | Reply

    Sorry, dhogaza, I didn’t make it clear at all that I meant to be sarcastic with my question about science revolution (I didn’t have Carter in my dossier of untrustworthy sources, though, thanks).

    Thanks also for that link to desmogblog, it looks really useful and a good complement to sourcewatch and exxonsecrets.

    I guess that if oceans were the cause of the warming by energy transfer to the atmosphere, they would be cooling somewhere, instead of getting warmer. I guess that there would also be some issue with TOA energy budget as there would be more energy going upwards from the surface. And I also think that, at some point, ocean temperature anomalies would have led instead of lagged (compared to land temperatures). I also think that southern hemisphere would be getting warmer faster than the northern hemisphere. I’m not an expert, though. Anyway, these peer-review flips are a bit of a pain in the neck :)

    Sorry for the off-topic, tamino.

  • dhogaza // July 23, 2009 at 4:44 pm | Reply

    Apparently Lindzen’s got a new negative feedback piece of work out that smashes mainstream AGW as well.

    Meanwhile, arctic ice doesn’t seem to be hearing the global cooling message.

  • Hank Roberts // July 23, 2009 at 6:07 pm | Reply

    David (Benson) — thank you for the link just above to the Battisti paper. His name on that page is a link to other material and his working group. I also found his work much cited by others in recent years, when I looked with Google Scholar. Very productive pointer!

    Dang, more to read ….

  • David B. Benson // July 23, 2009 at 9:09 pm | Reply

    Hank Roberts // July 23, 2009 at 6:07 pm — You are more than welcome!
    Thank you for the tip about the name link.

  • Alex Luta // July 23, 2009 at 10:11 pm | Reply

    I apologize for my delayed response. I was traveling. :)

    As you can see from the link i posted on July 15 (or you could just click on my name), i am a climate *policy* researcher. However, before i went into political science i was seriously considering natural science, specifically chemistry, so i am inclined to be very interested when somebody comes up to me and says that the scientific foundation of my work is fundamentally flawed. That is all that my interest is based on. I just want to go as far as my *limited* scientific acumen will take me.

    And, yes, i would be interested on such materials. I hate to admit it, but i hate to lose an argument, and i would like to be able to smite people if they ever stand up during one of my presentations and start “debunking” the “bad science” that the IPCC is “putting out there” to save their “cozy jobs” or some such.

    Thank you.

  • David B. Benson // July 24, 2009 at 12:45 am | Reply

    Alex Luta // July 23, 2009 at 10:11 pm — On Open Thread #14 Hank Roberts recently posted a link to CF Keller’s “Global Warming: a review of this mostly settled issue” Stoch Environ Res Risk Assess 23(2009). I think it will be just what you need.

    • Alex Luta // July 26, 2009 at 1:15 pm | Reply

      Heh, lovely. I had to go through my university’s servers to get a free copy of this, but i will sit myself down and read it.

      Thank you very much.

  • David B. Benson // July 24, 2009 at 1:45 am | Reply

    Consider figure 3(a) in
    2001 Marshall, J., Y. Kushnir, D.S. Battisti, P. Chang, J. Hurrell, M. McCartney and M. Visbeck: Atantic Climate Variability. Int. J. Climatology, 21, 1863-98,
    obtainable from Prof. Battisti’s web site. This is the power spectral density for the North Atlantic Oscillation. We can trust this due to the long record and the agreement between two difference power spectra estimation methods.

    This is a “slightly red” (pink?) spectrum; one supposes with much more data the power spectrum for the Pacific would show similar characteristics, but with peaks at different periods due to ocean size. There is a lot of power at low frequencies.

    Indeed, some time ago I ran FFT on the GISP2 temperatures of Alley, just for the Holocene. I obtained a red spectrum with no significant peaks. So then I tried a method based on the Lomb periodogram, designed to look for quasi-periodic behaviors in cardiograms, etc. At the limit of sensitivity it was possible to see slightly more power in the bands with periods between 90 and 30- years, but not for shorter periods down to the limit of around 22 years and not for longer periods up to the limit of several centuries. This actually appears to agree rather well with Hurrell’s index in figure 3(a), but not with the PC1 result in the figure. It also agrees fairly well with the SST tripole in figure 3(b). One certainly expects the GISP2 Greenland temperature proxy to be similar to that of the North Atlantic.

    In a Chilean conference paper I found an interesting discussion of the last two major El Ninos. The slides claimed that ENSO periods were 3 and 5 years; 15 is a multiple of both periods and the two large El Ninos were 15 years apart, constructive reinforcement. Also of interest is that the more recent one launched a Rossby wave which took 10 years to cross the Pacific. The point is that there are ways for the air-ocean system to put energy into long period effects.

    So now I think I have enough data to comment on the Swanson & Tsonis paper. With lots of power at long periods, it is enough to notice that if these just happen to constructively add across ocean basins there would be a rather noticeable wobble, persisting for some years, in the global temperature without having to posit any form of reorganization whatsoever. Such might indeed occur due to teleconnections, but as in so many other aspects of climate there simply is not a long enough record at enough different locations (for me) to know.

  • Barton Paul Levenson // July 24, 2009 at 8:40 am | Reply

    Lindzen’s paper says the feedback is in shortwave radiation.

    Shortwave radiation??? Visible light??? Is he saying the tropics glow more brightly when they heat up?

  • ab // July 24, 2009 at 4:51 pm | Reply

    #David B. Benson // July 23, 2009 at 2:12 am This lecture by David Battisti….
    In a paper*) NATURE, 428, 15 April 2004, p. 733, Dake Chen et al. suggested: that the evolution of El Niño is controlled to a larger degree by self-sustaining internal dynamics than by stochastic forcing”. This could mean that there is first the internal dynamic of the ocean, and only subsequently ENSO.
    *) Dake Chen et al.; Predictability of El Niño over the past 148 years

  • dhogaza // July 24, 2009 at 5:40 pm | Reply

    Lindzen’s paper says the feedback is in shortwave radiation.

    Shortwave radiation??? Visible light??? Is he saying the tropics glow more brightly when they heat up?
    </blockquote.

    reflected shortwave radiation, i.e. clouds, apparently …

    I just gave it a quick read-through thus far …

  • David B. Benson // July 25, 2009 at 9:50 pm | Reply

    ab // July 24, 2009 at 4:51 pm — Thanks. I am quite positi8ve that is true for the 3.8 year period component of ENSO. Too regular to be otherwise.

  • David B. Benson // July 27, 2009 at 10:32 pm | Reply

    “The Problem of Red Noise in Climate Regime Shift Detection”:
    http://www.beringclimate.noaa.gov/…/Red_noise_paper_v3_with_figures.pdf
    is short, to-the-point and relatedd to the main topic of this thread. The example is PDO; the pre-whitining technique does appear to demonstrate so-called regime shifts in 1948 and 1976 CE.

  • Hank Roberts // July 27, 2009 at 11:25 pm | Reply

    http://www.beringclimate.noaa.gov/regimes/Red_noise_paper_v3_with_figures.pdf

    but Acrobat8 crashed and FF3.5.1 closed unexpectedly on trying. Search for the title; there’s a HTML version Google provides.

    [Response: This appears to be nearly identical to Rodionov, S.N., 2006, The use of prewhitening in climate regime shift detection, Geophys. Res. Lett., 31, L12707, which is available here.

    Fascinating stuff! Well worth careful study.]

  • David B. Benson // July 28, 2009 at 12:34 am | Reply

    Hank Roberts // July 27, 2009 at 11:25 pm & Tamino — Thank you. Tamino’s link provides the published version of the study (which certainly improved in the revision).

  • David B. Benson // July 28, 2009 at 11:41 pm | Reply

    I have commented several times on the red noise spectrum of GISP2 temperatures during the Holocene. A nicely done wavelet analysis is
    Holocene climate variability on millennial scales recorded in Greenland ice cores
    A. Witt and A. Y. Schumann
    third paper down here:
    http://www.nonlin-processes-geophys.net/12/issue3.html
    with almost nothing but red noise for the most recent 13 ky (down to centennial scales). Knowing where to look, one can see the 8.2 kya event, but it is not statistically significant. Niether is Younger Dryas.

    Indeed, for the most recent 4.5 ky there is nothing but red noise at these long periods. Of some interest the the GISP2 ammonium record in figure 3 which seems to contain a regular structure at long periods. Note the 3–4 ky period throughout the entire 50 ky analysis. This might be tentatively identified as a flunctuation in Pacific deepwater with a storage time of around 2 ky causing periodic droughts in North America.

  • simple // August 8, 2009 at 11:42 am | Reply

    Hi,

    There is little doubt that the world is a choatic system and will act as such.

    Thus during a time of an external warming influence the rate of heat dissipation into any particular point in the system (lower troposphere temp) will vary although at first there will be a linear warming.

    After a critical point linear warming is lost to be replaced by times of comparitively less warming (can be even be apparent cooling due to changes in other factors (sunspots, La Nina etc..) and greater warming with jumps occuring between the two (funny attractors), although the overall warming of that part of system continues.

    If the warming influence continues the rise (as it is) the rate and size of changes also change. It therefore reasonable to predict that the rate of rise of surface temeprature will vary more and more dramatically although still continue to rise relentlessly; there are no real cooling periods just periods of faster and slower cooling with natural variations overlayed giving breif episodes of apparent cooling or cool years or runs of cooler years (e.g. 2007-8).

    Now whether we are in a slower warming period after 1998 is questionable. It does seem to be the case if the 1998 extreme is taken as a peak rather part of the trend, take the 10years from 1988-98 including 1998 and then 1999 to 2008 and there is a clear warming, despite 1998 effectively biasing the early ten years to be warmer however. Also it must the be remembered that the the surface temp is likley to be falsely low due to shading from brown clouds over Asia, Africa, Americas and the Pacific, the far greater than expected rate of ice melt (including the thinning from beneath of the arctic sea ice) that has occured, the low sunspots and the tendency of the Nina system to La Nina conditions. That is a lot more heat has been coming into the system from GHG than is apparent from ST and the apparent cooling is likely to be myth of relying on one measurement.

    It also seems to be the case the earth’s sensitivity to a warming force is also extremely variable as would be expected in the chaotic system and it does seem to change of time.

    However how fast can it change?

    Has the climate sensitivity altered over the last 100years on several occassions?

    It is quite clear that >50% of the time it is >3C and recent evidence suggests it is currently more like 5C.

    Will it or has it changed again?

    Will it Drop or fall?

    No way of knowing really, although it is likely that it will continue fluctuate as the size of the warming influence increases and lets face it CO2 is going up, EL Nino has just formed and sunspots are on the rise, arctic ice is decreasing, it appears oceans warm low level clouds dissipate or in other words all the warming influences are currently increasing and we still have the heat from the last 20-30years to make its way into the system.

    Lets hope the climate sensitivity doesn’t shift gear again or global warming will take us all by surpise by doing a rapid jump, although of course this may have already happened just it is lagged in the system as it is truly surprising that warming has continued despite increasing natural cooling influences since 2001.

    Anyway i’m rambling and the most rapid change in climate systems will be the changes in prevailing winds and weather patterns (this has already happened i’d say in the UK unless 3 winters and 3 summers of aborant jetstream positioning is just pure chance and not connected to the arctic melts and expanding tropics!).

    Change the wind patterns and change the regional climate overnight, from wet to dry or cold to hot or conbinations there of. The sort of thing eco-systems find hard to adapt to, occuring very rapidly.

    Also lets hope the heat dissipation doesn’t become turbulent with large swings in step wise heating and cooling events, otherwise the weather would get truly something to talk about, sudden expanding tropics, out bursts of cool winds to the mid tropics etc. Remember that the greatest cause of crop loss is wind damage!!!

    Maybe its time we seriously started not adding to the potential and remove Co2 and start planning for the adaptations we are going to need to be free from fossil fuels, intensive GHG agriculture, ground salination, extreme weather events, population migrations and flooding.

    Negative carbon living now that is a challenge for every individual!

  • Hank Roberts // August 8, 2009 at 4:33 pm | Reply

    Shorter and simpler:

    > > There is little doubt … (funny attractors)….
    > It also seems to be the case
    [ citation needed]
    > the earth’s sensitivity … is also
    > extremely variable
    [ citation needed]
    > as would be expected in the chaotic system
    > …and it does seem to change of time.
    [ citation needed]
    > … Has the climate sensitivity altered …
    > It is quite clear
    [ citation needed]
    > that >50% of the time it is >3C
    [ citation needed]
    > and recent evidence suggests
    [ citation needed]
    > it is currently more like 5C.
    [ citation needed]
    > … Anyway i’m rambling
    > … the greatest cause of crop loss is
    > wind damage!!!
    [ citation needed]

    I spent a few minutes trying to look up the wind damage claim and can’t sort it out; there are extensive data sets shared among crop insurance programs for example, but it looks like hail and rain rather than wind per se may be more of a problem.

    I think the point ’simple’ is trying to make is that climate change may cause more extreme weather; that can be supported with a little research.

Leave a Comment