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Global warming and the El Niño Southern Oscillation

What the science says...

The El Nino Southern Oscillation shows close correlation to global temperatures over the short term. However, it is unable to explain the long term warming trend over the past few decades.

Climate Myth...

It's El Niño
"Three Australasian researchers have shown that natural forces are the dominant influence on climate, in a study just published in the highly-regarded Journal of Geophysical Research. According to this study little or none of the late 20th century global warming and cooling can be attributed to human activity. The close relationship between ENSO and global temperature, as described in the paper, leaves little room for any warming driven by human carbon dioxide emissions. The available data indicate that future global temperatures will continue to change primarily in response to ENSO cycling, volcanic activity and solar changes." (Climate Depot)

The paper claiming a link between global warming and the El Niño Southern Oscillation (ENSO)  is Influence of the Southern Oscillation on tropospheric temperature (McLean 2009). What does the paper find? According to one of it's authors, Bob Carter,

"The close relationship between ENSO and global temperature, as described in the paper, leaves little room for any warming driven by human carbon dioxide emissions."

In other words, they claim that any global warming over the past few decades can be explained by El Niño activity.

How do they arrive at this conclusion? They begin by comparing satellite measurements of tropospheric temperature to El Niño activity. Figure 1 plots a 12 month running average of Global Tropospheric Temperature Anomaly (GTTA, the light grey line) and the Southern Oscillation Index (SOI, the black line).


Figure 1: Twelve-month running means of SOI (dark line) and MSU GTTA (light line) for the period 1980 to 2006 with major periods of volcanic activity indicated (McLean 2009).

The Southern Oscillation Index shows no long term trend (hence the term Oscillation) while the temperature record shows a long term warming trend. Consequently, they find only a weak correlation between temperature and SOI. Next, they compare derivative values of SOI and GTTA. This is done by subtracting the 12 month running average from the same average 1 year later. They do this to "remove the noise" from the data. They fail to mention it also removes any linear trend, which is obvious from just a few steps of basic arithmetic. It is also visually apparent when comparing the SOI derivative to the GTTA derivative in Figure 2:


Figure 2: Derivatives of SOI (dark line) and MSU GTTA (light line) for the period 1981–2007 after removing periods of volcanic influence (McLean 2009).

The linear warming trend has been removed from the temperature record, resulting in a close correlation between the filtered temperature and SOI. The implications from this analysis should be readily apparent. El Niño has a strong short term effect on global temperature but cannot explain the long term trend. In fact, this is a point made repeatedly on this website (eg - here and here).

This view is confirmed in other analyses. An examination of the temperature record from 1880 to 2007 finds internal variability such as El Nino has relatively small impact on the long term trend (Hoerling 2008). Instead, they find long term trends in sea surface temperatures are driven predominantly by the planet's energy imbalance.

There have been various attempts to filter out the ENSO signal from the temperature record. We've examined one such paper by Fawcett 2007 when addressing the global warming stopped in 1998 argument. Similarly, Thompson 2008 filters out the ENSO signal from the temperature record. What remains is a warming trend with less variability:


Figure 3: Surface air temperature records with ENSO signal removed. HadCRUT corrections by Thompson 2008, GISTEMP corrections by Real Climate.

Foster and Rahmstorf (2011) used a multiple linear regression approach to filter out the effects of volcanic and solar activity and ENSO.  They found that ENSO, as measured through the the Multivariate ENSO Index (MEI), had a slight cooling effect of about -0.014 to -0.023°C per decade in the surface and lower troposphere temperatures, respectively from 1979 through 2010 (Table 1, Figure 4).  This corresponds to 0.045 to 0.074°C cooling from ENSO since 1979, respectively.  The results are essentially unchanged when using SOI as opposed to MEI.

Table 1: Trends in  °C/decade of the signal components due to MEI, AOD and TSI in the regression of global temperature, for each of the five temperature records from 1979 to 2010.

table 3

Figure 7

Figure 4: Influence of exogenous factors on global temperature for GISS (blue) and RSS data (red). (a) MEI; (b) AOD; (c) TSI.

Like Foster and Rahmstorf, Lean and Rind (2008) performed a multiple linear regression on the temperature data, and found that although ENSO is responsible for approximately 12% of the observed global warming from 1955 to 2005, it actually had a small net cooling effect from 1979 to 2005.  Overall, from 1889 to 2005, ENSO can only explain approximately 2.3% of the observed global warming.

Ultimately, all the data analysis shouldn't distract us from the physical reality of what is happening to our climate. Over the past 4 decades, oceans all over the globe have been accumulating heat (Levitus 2008; Nuccitelli et al. 2012, Figure 5). The El Niño Southern Oscillation is an internal phenomenon where heat is exchanged between the atmosphere and ocean and cannot explain an overall buildup of global ocean heat. This points to an energy imbalance responsible for the long term trend (Wong 2005).

Fig 1

Figure 5: Land, atmosphere, and ice heating (red), 0-700 meter OHC increase (light blue), 700-2,000 meter OHC increase (dark blue).  From Nuccitelli et al. (2012),

Data analysis, physical observations and basic arithmetic all show ENSO cannot explain the long term warming trend over the past few decades. Hence the irony in Bob Carter's conclusion "The close relationship between ENSO and global temperature leaves little room for any warming driven by human carbon dioxide emissions". What his paper actually proves is once you remove any long term warming trend from the temperature record, it leaves little room for any warming.

Last updated on 2 December 2012 by dana1981. View Archives

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Further reading

NOAA have a very useful resource ENSO Cycle: Recent Evolution, Current Status and Predictions which features recent ENSO activity as well as model predictions of ENSO activity in the near future.

Comments

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Comments 1 to 50 out of 190:

  1. Great post. Another point - your Figure 1 shows the basic problem with this claim at a glance. The grey temperature line has a discernible upward trend, while the dark ENSO line does not. So ENSO doesn't match the warming trend, case closed.

    However, as the paper itself is behind a paywall, the key findings have been posted here, with the graph split into three at 1980 and 1995:

    With this split, the warming trend is much harder to spot.

    You can do the same thing with surface temps (NASA GISTEMP):
    GISTEMP 1958-2009 - trend is clear

    GISTEMP 1958-2009 in 3 slices - trend obscured

    A "trick" to "hide the incline" perhaps?
  2. Erl - for a warming trend, you have to increase the net energy on the planet. Where is the evidence of this in ANY ocean cycle. While the initiation point of an ENSO event remains tricky, (is it wholly a dynamical phenomena?), I would say that other aspects are now pretty well understood. I also note that "ENSO" emerges in climate models, and yet these models do not create temperature trends unless there is a forcing (like CO2 or solar) applied.
  3. scaddenup #2

    My understanding is that ENSO, La Nina, AMO etc are internal re-distributions of heat energy around the globe - not overall gain or loss of heat from the Earth system to space by forcing imbalances.
  4. Ken. So do I but Erl apparently does not.
  5. Please read:http://climatechange1.wordpress.com/2010/08/17/is-enso-rather-than-a-%E2%80%98greenhouse-effect%E2%80%99-the-origin-of-%E2%80%98climate-change%E2%80%99-by-erl-happ/
    Tell me this: What is responsible for the long term change in the differential pressure that drives the trade winds and tropical temperature?
  6. Continuing from #20 on the Goddard-is-cherrypicking-sea-level-data thread. The same statement was made as in #3 here: ENSO are, after all, cycles, which don't make much difference in the long term.

    However, as the familiar MEI graph shows, there seems to be a lot more red since about 1977 or so.


    From a fascinating model run made by Timmerman et al. 1999:

    The tropical Pacific climate system is thus predicted to undergo strong changes if emissions of greenhouse gases continue to increase. The climatic effects will be threefold.
    First, the mean climate in the tropical Pacific region will change towards a state corresponding to present-day El Nino conditions. It is therefore likely that events typical of El Nino will also become more frequent.
    Second, a stronger interannual variability will be superimposed on the changes in the mean state, so year-to-year variations may become more extreme under enhanced greenhouse conditions.
    Third, the interannual variability will be more strongly skewed, with strong cold events (relative to the warmer mean state) becoming more frequent.


    If I read that correctly, sounds like more red overall with the occasional deeper blue.
  7. Isn't the El Nino Southern Oscillation showing a long term trend towards stronger and more frequent El Ninos because of global warming? Because I read a myriad of studies suggesting this. But in recent years that trend seems to be dissipating or is too short of a time period to make any meaningful judgements? Is this trend towards stronger and more frequent El Ninos truly manifesting itself or is it just a fluke of nature?
  8. #7: "I read a myriad of studies suggesting this."

    It would be helpful if you would provide some references, rather than just 'a myriad.'

    "But in recent years that trend seems to be dissipating or is too short of a time period to make any meaningful judgements?"

    Look at the graph in #6. What 'trend seems to be dissipating' are you referring to?
    Also note the 2nd and 3rd points from the Timmerman paper:
    - year-to-year variations may become more extreme and
    - with strong cold events (relative to the warmer mean state) becoming more frequent.

    Or to put it in terms of a 'forecast':
    Continued warming with a 30% chance of occasional heavy snow in some areas. 50% chance of record droughts and/or record flooding. 95% chance of skeptics refusing to look at the long term and seizing on minimal data to say 'No its not!' 100% chance of inaction on the part of the US government.
  9. I would like to see an article where the ENSO argument of Bob Tisdale is being countered. The ENSO argument presented here is not the main skeptical argument on ENSO, after all. Tisdale is going further, claiming that the NINO3.4 index does not fully account for ENSO as a process. He purports to show that when the entire set of processes involved in the progression of the ENSO phenomenon is included, the ENSO IS able to explain global warming since the mid 70s.

    I would like to see you tackle HIS argument to show specifically where it fails.

    In my opinion, this site would not be complete without such an article.
  10. Kayell,

    If any real people took Tisdale's argument seriously, then this site would tackle it. This site is not, however, required to tackle every bit of nonsense generated by every person on earth.

    The fact that Tisdale's cr@p gets play on WUWT is meaningless (and says a lot about WUWT and its readership). Those people are lost, and will stay lost.

    For what it's worth, however, Tisdale's entire collage of nonsense fails on one basic point, the First Law of Thermodynamics. From where does the energy come that allows ENSO to heat the planet?

    Put another way, ENSO has been around for thousands of years. Why, suddenly, now, does each successive El Nino warm the planet (which is actually the opposite, La Nina's warm the planet), while La Nina's have no counteracting effect? Why is heat suddenly accumulating now due to ENSO, yet never before today? What's changed?

    What is the physical mechanism at work?

    And before you ask, no, I haven't paid good money to read his cr@ppy theories, and I won't. If you'd like to send a PDF of his nonsense, and if I decide I'm willing to waste a chunk of my life looking at it, then it can maybe discussed (although, really, I'd rather spend my time looking at real science that is going to affect the course of policy, not sideline nutjobbery that is really of no consequence to anything).

    Short of that... no, I don't see the need for SkS to debunk every bit of Galilean look-at-me-I've-got-it-I'm-a-genius nonsense that exists in the world.
    Response: [Dikran Marsupial] Please keep the discussion to the science and avoid inflamatory terms, regardless of the perceived provocation.
  11. Wow, that was really quite an aggressive response, I must say. Where did that come from?

    You keep calling his ENSO argument 'crap' and 'nonsense'. And yet you admit you haven't actually read what he says, what his argument in full is all about. Sounds like pure reflexive dismissal to me.

    If this is such a nutcase piece of hypothesizing, then it should be exceedingly easy to actually show specifically where it fails. Your 1st law of thermodynamics counter-argument is of course only based in you not having read what he says of the matter. You know, I know and he knows where the energy is coming from. You know, I know and he knows how the Pacific uptake of solar energy varies wildly between La Niña and El Niño conditions.
    Response: [Dikran Marsupial] Please can EVERYBODY keep the discussion even tempered, or I will start deleting posts.

    Kayell: I suspect the tone of the reply was prompted by the rhetorical tone of your initial post "In my opinion, this site would not be complete without such an article. ". If you keep your posts purely scientific and avoid rhetoric you will find you get a much better response. If you want an argument addressed, then at least provide a link to where the argument is presented. If you know where the energy is coming from, then you ought to be in a position to debunk the argument yourself.
  12. Kayell,

    I'm not paying good money to Tisdale to read his nonsense. Period.

    [snip]

    [Why do you think it is that no-one except for WUWT regulars are paying any attention to his theory?]
    Response: [Dikran Marsupial] Discussion of motivations snipped. Please lets just keep this to the science, and wait and see if Kayell can come back with a more substantive description of the argument.
  13. Presumably Tisdale shows that ENSO's influence has become far more extreme over the past few decades, that it is unleashing astounding quantities of formerly stored and hidden energy? Does he explain how that works? Or does the hypothesis only work if explained in isolation from other evidence?

    For instance, the overwhelming balance of evidence indicates that Arctic sea ice is going through area excursions and persistent volume loss in a way that's very unusual and likely not to have taken place for many thousands of years. For this to happen requires some input of additional heat energy to the Arctic Ocean and indeed other measurements confirm that's the case. Given the timeline of Arctic sea ice behavior, integrating these observations of sudden change with Tisdale's approach requires some mechanism that could sequester energy for many thousands of years and then suddenly release it. How does that work? As we all know, energy in the form of heat is very difficult to keep in one place. So what's the storage mechanism for Tisdale's energy?
  14. Kayell - Tisdale's argument appears to be that the ENSO is not symmetric, that La Nina absorbs more energy than El Nino releases, and thus the heat content of the Earth rises in 'steps'.

    Problems with his hypothesis:

    * Why would the ENSO be asymmetric now, when it hasn't been for the last few hundred years - effects require causes and mechanisms, and he has proposed nothing plausible in that regard.

    * The oceans and the atmosphere have warmed, especially over the last 40 years - and given the Stefan-Boltzmann relationship of emitted power with temperature, if the atmosphere was radiatively unchanged we would have a negative (cooling) top of atmosphere (TOA) balance. The evidence shows a postive balance (less leaving than arriving), thus contradicting Tisdale. This is a major problem with any number of 'skeptic' theories.

    * His evidence (what there is of it) consists of extremely short "step" changes of sea surface temperatures - and as has been discussed here and elsewhere (as in the Escalator graphic), those are artifacts of noisy data and statistically insignificant short term trends.

    * Observed warming (25*10^22 Joules over the last 40 years in the top 2000 meters of the oceans) has occurred in a fairly steady rise. Not by "steps".

    * His statistics, if you can call them that, are terrible - he doesn't know enough to numerically support his hypotheses, and what he presents actually contradicts his ideas if you actually know what the numbers mean.

    ---

    In short, Tisdale's hypotheses consist of handwaving over statistically meaningless short periods and changes. None of it has been peer-reviewed, he is clearly not familiar with the body of peer-reviewed science and data on the issue, it's unsupported and unsupportable pixie dust.

    And it's rather frustrating to see such nonsense taken seriously by anyone, let alone be pushed repeatedly by Tisdale in his insulting and accusatory terms (multiple accusations of deception, conspiracy, data manipulation, etc). Hence the impatience from those who know anything about the ENSO and global warming...
  15. Kayell - "...claiming that the NINO3.4 index does not fully account for ENSO as a process..."

    I find this a very curious strawman argument. The NINO3.4 index is one measure (of many) of an acyclic process - consisting of wind driven changes in ocean overturn and hence heat exchange with the atmosphere.

    That index is not the process. I cannot think of anyone who has claimed it is (hence the strawman). It is, rather, one measure of that process, much as GDP is one measure of economic activity.

    If the ENSO index is insufficient to track the process, then what ENSO aspects does Tisdale think have changed in the 1970's? And why? How would he measure that, in a statistically significant fashion - where is his evidence? His favorite measure, sea surface temperature changes in various regions, is actually part of the NINO3.4 index; he's presented nothing new.

    As I said at the start, attacking the index is a Strawman Fallacy. The ENSO can be measured/tracked with trade winds, with atmospheric pressures (Southern Oscillation Index, SOI), or with sea surface temperatures (as in the NINO3.4 index). If Tisdale thinks these are insufficient, it is on him to present evidence of supportable process changes that have diverged from historic behaviors. He has not.
  16. Sphaerica - "Put another way, ENSO has been around for thousands of years"

    ENSO has been around for millions of years. There are enough people responding to Kayell, so I'll stay out of this.
  17. Frankly, I would think you would pounce on the opportunity to rip this particular ’skeptical’ argument apart, to present a clinical, blow-by-blow refutation of it. It is (still in MY opinion, though) the most robust, cohesive skeptical argument AGAINST an anthropogenic and FOR a natural cause of global warming out there. And it’s getting more and more traction amongst ’the skeptical crowd’. So it is indeed a real, important and relevant skeptical argument. It is an easy to grasp argument, mostly descriptive actually, and does not make use of any models or sets of novel assumptions, only available data. The physical mechanisms at work and their effects are readily observable through space and time and well known and described in the geophysical literature. In a way the argument explains itself once you understand the processes at hand and simply track the energy through the Earth system by looking at the various sets of data.

    If you’ll let me, I would be happy to give you a compendious summary of the argument.
    Response: [DB] As noted by Phippe and KR below, the skeptical thing to do would be to first address those questions already put to you on this thread. Those genuinely interested in advancing the scientific understanding should feel that to be an imperative.
  18. Kayell, why don't you start by adressing the robust, cohesive relevant critics to the very premise of that argument that have already been presented above by various contributors? That would be a necessary first step.

    Also, keep in mind that here we concern ourselves with scientific arguments that are supported by peer-reviewed scientific litterature; Tisdale's piece not only doesn't fit that description but also betrays a lack of familiarity with the relevant scientific litterature by its author.

    There is no doubt that the "argument" will gain traction among those with little scientific literacy on the subject, especially if they're frantically looking for any old useable bit to confirm what they want to believe. It doesn't make it better than any other argument that particular public will buy.
  19. Kayell / Kristian - I believe I have discussed Tisdale's arguments in some detail. I would be interested in any comments you might have on the lack of statistical significance of his "step" time periods, the positive (increasing energy) TOA balance that directly contradicts his ENSO attribution of global warming, the fact that sea surface temperatures (SST's) he argues from are actually included in both the NINO3.4 index and the MEI, etc.

    Well? What processes does Tisdale point to, processes that for some reason have changed from their many 10's of thousands of years history to suddenly warm the earth over the last 150? You know, evidence?

    Please point to data supporting your assertions, as per the opening post. (I'm afraid I will not take hand-waving very seriously...)
  20. Philippe Chantreau and KR,

    Since people here so far haven't adressed the actual argument at all, only their strawman versions of it, I see no reason spending time answering their/your appararent objections. Rather I would prefer presenting the argument.

    Dikran, are you seriously asking me to answer all these
    'objections' to the argument before I actually describe the argument to you? That's a strange way of advancing a discussion ...
    Response: [Dikran Marsupial] Kayell, I am telling you to avoid rhetoric and instead stick to the science. If you want people to discuss Tisdales argument then either explain it in detail yourself, or provide a link to somewhere that does. The first law of thermodynamics is a perfectly good explanation of why Tisdales argument is wrong. If you have an objection then present it. If you continue to avoid discussing the science you will be making it clear that you are not interested in the answer to your questions and are merely trolling. The ball is in your court, I suggest you return it.
  21. Kayell / Kristian - If you feel I have incorrectly understood Tisdale's argument, perhaps you could (clearly) state what you feel his argument is? Or in some other fashion indicate what interpretive error you think has been made?

    ...without a statement of where you think the argument stands, it's absurd to claim that I (and others) have not addressed it. On my part, I believe I have addressed Tisdale's unsupported, and contradicted by evidence, hypotheses. Since you feel he's made a good argument, it falls upon you to state what that is, and why the various disagreements are (potentially) not valid.

    Barring that, I would (IMO) consider your posts so far on this thread to be assertions without evidence.

    "Rather I would prefer presenting the argument."

    By all means, please do.
  22. Kayell/Kristian - I said I'd stay out of this, but I've changed my mind. Bob Tisdale himself is unable to explain his hypothesis, so maybe you can have a shot at it?

    No one here is likely to waste one and a half hours watching his videos, so please explain to us what you find so compelling.
  23. For anyone interested, the discussion of the proposed mechanism starts at about 29:15.
  24. KR says: "By all means, please do."

    Thanks. That's all I'm asking for. I will.

    It'll take me more than five minutes though, and that's all I have to spare right now.

    So later.
    Response: [Dikran Marsupial] We will be patient, please do take time to present the argument carefully. I would recommend presenting it as a set of numbered steps that form the logical chain of the argument, I have found that works well in the past as then counter arguments can be discussed for each link in the chain separately in detail.
  25. Dikran says: "If you want people to discuss Tisdales argument then (...) explain it in detail yourself (...)"

    Exactly. I haven't yet presented it. [snip]

    Response: [Dikran Maruspial] You have been asked to present the argument, so please stop complaining about the tone of the discussion and present it so that we can have a productive discussion. I have snipped the remainder of your post so as not to distract further from discussion the science, if you want a positive reception then it is straightforward, stick to the science, regardless of perceived provocation.
  26. Tristan - Tisdale replied basically insisting La Nina is responsible for ocean warming. Colour me unimpressed.

    La Nina is an interval when the Earth sees a net gain in energy, and El Nino a net loss, but this isn't some novel observation, I've discussed this, for instance, in this SkS post: Search For 'Missing Heat' Confirms More Global Warming 'In The Pipeline'. See Figure 3 and the associated heading discussion.

    More importantly The ENSO-related energy fluxes balance out to zero in the long-term. If they didn't (as Tisdale seems to think) the planet would go on warming indefinitely. It's the same problem those Scafetta climastrology papers have - not only do they have to match recent observations, they also have to match with older observations - and that's where they quickly run aground.

    Increased levels of greenhouse gases heat the ocean, by lowering the thermal gradient in the thin cool skin layer of the surface. This reduces the amount of heat lost (from sunlight) to the (typically) cooler atmosphere, and the oceans warm as a consequence. That's why there is such a striking correlation between atmospheric carbon dioxide and temperature (aka ocean heat content) in the ice core reconstructions.

    Vostok ice core records for carbon dioxide concentration (Petit 2000) and temperature change (Barnola 2003)

    However, ocean heat can indeed vary dramatically in the short-term due to changes in aerosols, and especially cloud cover, in the atmosphere (which alters the amount of sunlight heating the surface ocean). So if you just look at the data, without a proper statistical analysis (as Tisdale is prone to), you can convince yourself of anything.

    If Tisdale's misunderstandings gain any traction, we'll get around to debunking it, but it's not a priority at the moment.
  27. I find it strange behaviour to insist anything that has no established science behind it. The thing I took from his video was merely how certain of his conclusion he was.
  28. As other have noted above it's been directly pointed out to Tisdale by many people (including me) that his argument breaks the first law of thermodynamics. He always blathers around the point but never addresses it properly.

    Although most would dismiss his pseudoscience as preposterous, at some point it may actually be worth a coda to formalise rebuttal of his nonsense. It's a sad state of affairs though that it might have to go to that extent... but then, that describes just about all denialism.
  29. Tisdale has now stated that "No one from SkS will never be able to find any flaws, because they very obviously can’t fathom the subject matter."

    Hmmm - claims that nobody can fathom your understated brilliance? Regarding a blog theory contradicted by historic observations (long term neutral average of ENSO), current observations (TOA spectral changes in GHG absorption that demonstrate GHG causation, not ENSO), and basic thermodynamics (claiming atmospheric warming comes from recent excess of El Nino's over La Nina's, yet the oceans are warming too - where does all that energy come from)? All of which has never been discussed or examined in the peer-reviewed literature, by those who study this data? Let alone the issues with his "evidence" lacking any connection to statistical significance...

    I was actually rather surprised to find that claims of "nobody can fathom my subject matter" isn't part of the Crackpot Index; it really belongs there. Ad hominem fallacies aside - if you cannot explain your theories well enough to be understood, you probably don't understand them yourself.

    ---

    Kayell / Kristian - In answer to your original question, 'theories' such as Tisdale's have no place in a scientific discussion - beyond noting that they don't hold up to examination.
  30. KR:

    I believe there is only one appropriate response to Tisdale's claim with respect to Skeptical Science & its contributors' ability to "fathom the subject matter" regarding his confusion surrounding ENSO and climate forcings.
  31. I'm still waiting for someone to cogently present Tisdale's case (without charging for it).
  32. What an excellent chance for Bob Tisdale to argue a specific point and potentially advance the science. Come on, Bob. I'd like to hear your ENSO argument without the heavy sauce of rhetoric. Surely there are at least a few people here who can understand the dynamics as well as you. Surely you're capable of explaining it to the less gifted of us, no? You can preach to the choir all day long at WUWT, and all you'll get is blank-eyed head nodding. Here you have the chance to convince the unconvinced, to put your argument to the test of fire, and to engage in the perfectly healthy behavior of getting feedback from the community. Surely SkS can set up a forum for extended dialogue on a specific issue or two (say ENSO and SST in general or OHC?). I really respect Pielke Sr. more now for wading into the thornbush and having his say. It's refreshing when the discussion isn't rhetorical cruise missiles lobbed from thousands of km away but is instead look-me-in-the-eye-and-tell-me-I'm-not-human dialogue, and I think SkS is the best place for a rhetorically toned-down discussion of the issue: wide reach (continually referenced across the mainstream news network) and a relatively effective comments policy.
  33. As an addendum, Tisdale should also look at John Nielsen-Gammon's analysis, which clearly shows grouped El Nino, La Nina, and ENSO-neutral years all trending upwards in temperatures over the last 50 years. This can hardly be the result of (as Tisdale claims) one or two decades of El Nino heavy ENSO activity.

  34. It is said that it is only in the act of teaching that an educator can truly become the master of what he teaches.

    Mastery awaits Mr. Tisdale...
  35. Here is PART 1:

    Like I said, Tisdale's version of the ENSO argument is pretty straightforward. It is NOT based on some foregone conclusion about the cause of global warming. It is a direct result of an inevitable conclusion arrived at AFTER looking at the real-world observational data at hand, an explanation derived from what we actually see happening in the Earth system as time passes, AND on what we know about the ENSO process and how it is observed to work, both in the Pacific and globally, rather than from a theoretical construct of assumed physical net effects on the complex planetary climate system as a whole.

    The argument follows the scientific method thus: I (or Bob) start out by observing a curious and, quite frankly, striking similarity between the NINO3.4 and the global SSTA curves over the last 30+ years (well, even much further back than this, but Tisdale's argument was always mainly based on data from the satellite era). This is certainly no new discovery. I think we can all agree on that the primary global temperature swings up and down, the large short-term variations in global temperature, are driven by the ENSO's mighty oceanic fluctuations in the East Pacific (where the NINO3.4 resides) and their worldwide impact being propagated partly by ocean currents, partly by atmospheric teleconnections. The global temperature goes up when NINO3.4 goes up (El Niño). And the global temperature goes down when the NINO3.4 goes down (La Niña).

    What happens then if we 'detrend' the global SSTA since 1981 and scale it against the NINO3.4? That is, we take away the obvious upward trend in the global to see how close the fit with NINO really is. This is only out of curiosity. Scientific curiosity. No one is yet suggesting or claiming anything. We just want to take a closer look at how the different data relates to one another. So yes, I'm 'manipulating' the global curve, no need to remind me.

    Here is the result:


    Quite an astounding fit. And it will surprise no one. We know why the fit is so good. You will notice the global imprints in 1982-83/84 of the El Chichón eruption and especially in the wake of the powerful Pinatubo eruption, ~1992-95. Other than that you will see some 'extra' global heat (extra, that is, relative to a 'normal' (proportional) global response to the NINO signal) piling up during the first directly following La Niña year after a few of the El Niño's along the composite plot. But this extra heat always seems to be dissipated again shortly after this first following La Niña - the global soon after back on level with NINO.

    So far, so good. What's next? Yup, that significant global upward trend that I got rid of. It's there, after all. But where does it come from? How do we follow its progression? Where do we look? What do we look for?

    I will let you in on a little secret. When I 'detrended' the global SSTA curve in the graph above, I didn't use a statistical tool to remove a general upward trend. All I did was to pull it down at two (2) short sections: two datapoints in the last half of 1987 (July and November) and one datapoint in the beginning of 1999 (January). Why those two intervals specifically? This will become apparent as we move along (in Part 2). Bear this in mind ...

    There is another way of showing the exact same thing, only WITHOUT removing the long term trend from the global SSTA:


    (The NINO3.4 is here alligned with the global curve between 1981 and 1987/88.)


    (The NINO3.4 is here alligned with the global curve between 1988 and 1997/98.)


    (The NINO3.4 is here alligned with the global curve between 1998 and 2012.)

    Here is a more detailed look at the last 'level', the stretch since 1996, without volcanic impact, across the global upward shift occuring through 1998, and all the way down past the El Niño of 2009/10 and the following La Niña 2010/11:


    (The two red squares mark the conspicuous piling up of extra heat globally during the transitions between the particular ENSO events of El Niño 1997/98 and La Niña 1998/99 and El Niño 2009/10 and La Niña 2010/11. The first is followed by a raised global level in mean SSTA relative to the NINO3.4 curve. The second one isn't. At least, not yet.)

    What can we conclude from all this? Not much as of yet. Except this: Global SSTA follow and mimic the major up and down temperature swings (El Niños and La Niñas) of the East Tropical Pacific on interannual time scales. AND, they also seem to follow the TREND in NINO3.4 rather slavishly over the last 30-31 years, that is, barring two (2) specific instances of marked and sudden global upward shifts relative to NINO.

    That is, along virtually the entire record there is no need for an explanation of the evolution of the global curve besides the well-known relationship between it and the East Tropical Pacific - the already mentioned short-term variations, the primary ups and downs. Here there simply is no extra global warming trend outside of this close relationship, no increasing divergence between the two.

    But then there are the upward shifts. The only places where the global curve diverge permanently from the NINO curve. There are only (and by that I mean ONLY) two cases between 1981 and 2012 where the extra heat piled up globally after an El Niño and during the transition to the first following La Niña is never fully made up for before the ENSO pendulum turns and the heat comes in again, both in the NINO3.4 region and globally. This is during and after the second and final peak of the 1986/87/88 El Niño, on the NINO way down towards the bottom of the very deep La Niña of 1988/89, and during and especially after the peak of the 1997/98 El Niño, on the NINO way down towards the bottom of the deep La Niña of 1998/99.

    This can be illustrated like this:


    (Bear with me on the Norwegian labelling. 'Trinn' is simply 'Level'. 'Ekstra varme globalt' means 'Extra heat globally'. Notice that here the pink curve is NINO3.4 and the black one is the global.)

    Just give this a moment's thought. All we're doing is looking at the data. I'm just stating what the data at hand is telling us. There simply IS no steadily increasing divergence between NINO3.4 and global SSTA between late 1981 and late summer/early autumn of 2012. The ENTIRE global rise above the NINO3.4 occurs at two specific instances. Not at any other time.

    In my world, then these two 'specific instances' are the ones up for closer inspection. THEY need an explanation. Not the rest of the graph. We've found something interesting at specific points in the data record and we want to check them out a bit more closely.

    We follow the scientific method and ask ourselves:

    How do these sudden and marked global upward shifts come to be? Seeing how extremely influential the ENSO processes are on the regular global temperature amplitudes, it would be a strange scientific approach to all of a sudden exclude ENSO from any further involvement in the ensuing investigation, as a possible factor also in the distinct upward shifts. By all means, it hasn't yet been shown to be the case. But it would be wise to at least follow that lead. To see if something out of the ordinary might have occured in those two particular cases.
    Response: [Dikran Marsupial] Images inserted for readability, hopefully without mistakes. It would be best if the subsequent parts have the images in-line (there is advice on HTML formatting for SkS posts here). However I would recommend that you do not proceed onto part 2 until we have had a chance to digest part 1 and for relevant questions to be answered. Please can everybody respond to this post in a calm and scientific manner.
  36. Kayell,

    Well, you got me to thinking, and I realized that Tisdale is so close to being right, but he got the most important parts wrong. See, El Niño events confuse everyone because they raise observed atmospheric temperatures, so people think that means "ah ha! warming!" But in reality, the planet sheds more heat during El Niño events, because the warmer atmosphere emits more radiation. It's sort of like a bathtub overflowing.

    What matters more is La Niña events, where the atmosphere is cool, but this means that the planet doesn't radiate heat well (it's basically trapped in the ocean), so this must be what is really causing global warming (or, rather, a lack of global cooling, as Jo Nova likes to say).

    So I broke the temperatures up at large La Niña events, and used that to "detrend" the global temperatures. Let's take a look (I helped you out by adding blue vertical bars where I broke the temperature record... the original temperature record is in green, while red is the "detrended" temperatures):



    Of course I didn't rescale the ENSO and Global Temperatures to match, a step you performed but seemingly failed to mention. Still...

    Hmmm. My graph looks closer than yours, using Tisdale's method. So I must be right!!!



    La Niña is causing global warming!!!!

    Or is it pirates? Hang on. If I can find a graph of pirate populations, I'm sure I can make pirates the cause of global warming.

    [This climate science stuff is so easy! Anyone can do it!]
  37. Kayell,

    FIrst off, I should say I appreciate you putting together the summary.

    I have a few questions regarding the data.

    1) Do you have a link to the specific dataset(s)?
    2) Is the NINO3.4 data processed in anyway? and if so, how?
  38. Do we get to see where all our extra energy is coming from in Kayell's Part 2, or will that be left as an exercise for the reader? Put another way, how is ENSO creating all the extra energy we're seeing? How long can ENSO continue raising the global temperature? If as we've seen the ocean stubbornly continues to warm during the period Kayell is describing, where's the energy source? Or is there a disproportionate increasingly refrigerated cool patch in the E. Pacific we've missed?

    A simple question with an answer readily to hand, surely?
  39. Oh, that's an interesting analysis Sphaerica.

    The next step would be to take the difference between NINO and SST, and do an automated breakpoint analysis on it. That might give an objective test of whether Nina breakpoints are better than Nino breakpoints, and whether either is really reflected by the data.

    A more rudimentary test would be to compare the AIC between a linear detrend and both sets of piecewise constant offsets.

    Tamino's post 'Steps' covers the methods.
  40. KR, Philippe Chantreau, Rob Painting, Sphaerica, et al.: The basis of this discussion appears to have been this video that appeared on the WUWT-TV webcast. Since some of you have not watched the video, you would have missed the bases for it. Therefore, let’s start with satellite-era sea surface temperature data and let me then ask you to explain the following:

    The East Pacific Ocean (90S-90N, 180-80W) has not warmed since the start of the satellite-based Reynolds OI.v2 sea surface temperature dataset, yet the multi-model mean of the CMIP3 (IPCC AR4) and CMIP5 (IPCC AR5) simulations of sea surface temperatures say, if they were warmed by anthropogenic forcings, they should have warmed approximately 0.42 to 0.44 deg C. Why hasn’t the East Pacific warmed?

    The detrended sea surface temperature anomalies for the Rest of the World (90S-90N, 80W-180) diverge significantly from scaled NINO3.4 sea surface temperature anomalies in 4 places. Other than those four-multiyear periods, the detrended sea surface temperature anomalies for the Rest of the World mimic the scaled ENSO index. The first and third divergences are caused by the eruptions or El Chichon and Mount Pinatubo. Why does the detrended data diverge from the ENSO index during the 1988/89 and 1998/99/00/01 La Niñas? According to numerous peer-reviewed papers, surface temperatures respond proportionally to El Niño and La Niña events, but it’s obvious they do not.

    I’ve answered those two questions in the video. Can you answer those questions? The data is available in an easy to use form through the KNMI Climate Explorer. Feel free to confirm my results in the above graphs.

    Response:

    [DB] To reiterate Ian's questions, so the dialogue can proceed:

    1) Do you have a link to the specific dataset(s)?

    2) Is the NINO3.4 data processed in anyway? and if so, how?

  41. Bob,

    1) Regarding your first point:

    The sea surface temperature is of course strongly influenced by ENSO and interdecadal variability. Now when you are taking the ensemble mean of CMIP3/5 models, you are effectively averaging out all the internal variability, so the ensemble mean is just the expected response due to external forcing (e.g. solar, GHG, aerosol etc).

    You are comparing data with a particular realization of internal variability to data with internal variability filtered out. You are effectively comparing apples to oranges, so of course they look different.

    To actually make a sensible analysis, you will at the very least have to look into internal variability of each model run, which entail comparing a large number individual model runs.

    To answer your question, a far more plausible explanation is internal variability (e.g. PDO).

    2) Regarding your second point,
    (i) What scaling and time shifting have you applied to the NINO3.4 data?
    (ii) You said " According to numerous peer-reviewed papers, surface temperatures respond proportionally to El Niño and La Niña events, but it’s obvious they do not." Can you provide references?
  42. IanC: Excuse the delay. 

    You replied, “You are comparing data with a particular realization of internal variability to data with internal variability filtered out. You are effectively comparing apples to oranges, so of course they look different.”

    I assume this is a discussion of the East Pacific data. The appearances are not in question. The trends are.

    You replied, “To actually make a sensible analysis, you will at the very least have to look into internal variability of each model run, which entail comparing a large number individual model runs.”

    Not me. I’m done with my analysis. It is the responsibility of the party wishing to dispute my results to show the effects of the point that party wants to introduce to the discussion. With that in mind, the models do such a poor job of simulating ENSO you’d be better off trying to remove the effects of ENSO from the East Pacific sea surface temperature data. Then you won’t have to analyze each of the dozens and dozens of model runs. If you don’t want to do that, that’s okay, because the “Rest of the World” data still needs to be explored.

    You replied, “To answer your question, a far more plausible explanation is internal variability (e.g. PDO).”

    Unfortunately, that explanation doesn’t work for a number of reasons. (a) The PDO represents the standardized leading Principal Component of the sea surface temperature anomalies of the North Pacific north of 20N after the global temperatures have been removed, not the sea surface temperature anomalies. (b) The standardization of the PDO exaggerates its actual variability by a factor of about 5.6, if memory serves. In other words, the standardization exaggerates the importance of the PDO. (c) The PDO is actually inversely related to the sea surface temperature anomalies of that portion of the North Pacific on decadal timescales. (d) The PDO is an aftereffect of ENSO and the sea level pressure of the North Pacific. The sea level pressure of the North Pacific causes the difference between the PDO and ENSO. (e) The dominant component of the PDO is the sea surface temperature of the Kuroshio-Oyashio Extension, in the western North Pacific, not the East Pacific.

    You asked, “What scaling and time shifting have you applied to the NINO3.4 data?”

    The scaling factor is 0.12 and there’s a 6-month lag.

    You asked, “Can you provide references?”

    Yup. Every study that attempts to remove the effects of ENSO from the surface temperature record by scaling an ENSO index and by subtracting the scaled and lagged ENSO index from surface temperatures assumes surface temperatures respond proportionally to El Niño and La Niña events. Examples in alphabetical order:

    Foster and Rahmstorf (2011) “Global Temperature Evolution 1979–2010

    And:

    Lean and Rind (2009) How Will Earth’s Surface Temperature Change in Future Decades?

    And:

    Lean and Rind (2008) How Natural and Anthropogenic Influences Alter Global and Regional Surface Temperatures: 1889 to 2006

    And:

    Santer et al (2001), Accounting for the effects of volcanoes and ENSO in comparisons of modeled and observed temperature trends

    And:

    Thompson et al (2008), Identifying signatures of natural climate variability in time series of global-mean surface temperature: Methodology and Insights

    And:

    Trenberth et al (2002) Evolution of El Nino–Southern Oscillation and global atmospheric surface temperatures (See note 1)

    And:

    Wigley, T. M. L. (2000), ENSO, volcanoes, and record-breaking temperatures

    Note 1: Trenberth et al (2002) included the following caveat (my boldface):

    “The main tool used in this study is correlation and regression analysis that, through least squares fitting, tends to emphasize the larger events. This seems appropriate as it is in those events that the signal is clearly larger than the noise. Moreover, the method properly weights each event (unlike many composite analyses). Although it is possible to use regression to eliminate the linear portion of the global mean temperature signal associated with ENSO, the processes that contribute regionally to the global mean differ considerably, and the linear approach likely leaves an ENSO residual.”


    The divergences shown in brown are those ENSO residuals.

    Moderator DB asked, “Do you have a link to the specific dataset(s)?”

    The Reynolds OI.v2 data is available on a gridded basis through the KNMI Climate Explorer:

    http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere

    And through the NOAA NOMADS website:

    http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_sst.sh?ctlfile=monoiv2.ctl&varlist=on&new_window=on&lite=&ptype=ts&dir=

    The coordinates of the NINO3.4 region are 5S-5N, 170W-120W. The coordinates for the East Pacific is 90S-90N, 180-80W. And the coordinates for the Rest of the World are 90S-90N, 80W-180. I provided a brief introduction to the KNMI Climate Explorer here:

    http://bobtisdale.wordpress.com/2010/12/30/very-basic-introduction-to-the-knmi-climate-explorer/

    And DB asked, “Is the NINO3.4 data processed in anyway? and if so, how?”

    The NINO3.4 sea surface temperature anomalies were scaled by a factor is 0.12, lagged 6 months, and both datasets in the graph of the detrended Rest of the World data were smoothed with 13-month running-mean filters.

    Regards

  43. Bob Tisdale, you wrote, "The East Pacific Ocean (90S-90N, 180-80W) has not warmed since the start of the satellite-based Reynolds OI.v2 sea surface temperature dataset".

    The Reynolds OI.v2 data set is normalized to the period 1971-2000. The NOAA website you link to above plots data from Nov 1, 1982. To what date do you refer when you mention "the start of the satellite-based" dataset?
  44. Tom Curtis asked, "To what date do you refer when you mention 'the start of the satellite-based' dataset?"

    Since we're discussing the monthly Reynolds OI.v2 data, the first month is November 1981.
  45. Thankyou. I notice that the strongest correlation between Nino 3.4 and global SST is when global SST lag Nino 3.4 by nine weeks. In your comparison, you say you used a 6 month (equivalent to a 26 week) lag. Why did you use a lag 17 weeks longer than that indicated by the data?
  46. Not to Distract too much from Tom Curtis' points above, but I would be interested if Bob Tisdale could answer KR's three underlined points in post #29 on this thread. Frankly, I feel that until he works out and demonstrates to the world:

    1: why ENSO should suddenly be involved with warming the world despite a long-term (multicentury) neutral average)

    2: why the demonstrated TOA spectral changes in IR emission/absorption that have CO2's fingerprints all over it are unimportant.

    3: (perhaps most importantly) what is the energy source that allows the oceans to drive atmospheric temperature changes while themselves warming on a global scale? Where is the energy coming from, Bob?

    Until then, selective examination of partial regions of ocean basin data are, to me, the oceanographic equivalent of suggesting that a cold winter's day in Reykjavik disproves global warming. Just a more fancy cherry-pick, but a cherry-pick, nonetheless.
  47. PART 2

    We continue to explore the satellite-based SST data from Reynolds OI.v2 (Nov'81-Oct'12) and see what patterns it might reveal.

    This graph, global SSTA:


    is the area weighted sum of the two following subsets:

    (left: The World Ocean Outside the East Pacific - 90N-90S, 80W-180E; 2/3rds of the global ocean
    right: The East Pacific Ocean - 90N-90S, 180-80W; 1/3rd of the global ocean)


    It was when looking at these two SSTA graphs, together producing the global graph above, that Tisdale had his eureka moment.

    If we superimpose the two global subset graphs above on each other, we see quite clearly specifically where the discrepancy between the East Pacific and the global SSTA curve (recalling Part 1) primarily arises:


    The NINO3.4 region is located in the East Pacific Ocean. Its signal totally dominates the SSTA evolution of that basin. According to the graph above, there is no upward trend in SSTA in the East Pacific Ocean since at least 1981. That's 1/3rd of the global ocean. Look at this map (from GISTEMP):


    It shows the global distribution of temperature change between 1982 and 2011. Please disregard the continental parts at this point. The oceanic change (its size and distribution) is calculated using Reynolds OI.v2. I've defined the East Pacific Ocean (65N-60S, 180-80W) and the NINO3.4 region (5N-5S, 170-120W), the latter making up ~5,7% (!) of the former.

    There's a distinct pattern manifesting itself here. Peculiarly, the West Pacific is one of two sectors of the world ocean (the other being the North Atlantic) displaying a particularly large positive change over the period in question. It has experienced a pronounced warming. And this even while sitting just next to (and being intimately oceanically linked to) the one major region of the world ocean that hasn't warmed at all. In fact, barring those two sub- to extratropical warm tongues coming in from the West Pacific, the East Pacific Ocean (and specifically the equatorial NINO3.4 region) has actually cooled since 1982.

    This striking contrast between two neighboring, tightly interconnected sectors of the same ocean basin alone should tell us something.

    What is going on?

    Let's get back to the SSTA graph for the world ocean outside the East Pacific:


    A staircase if ever there was one. This is how the change in SSTs outside the East Pacific in the GISTEMP map above actually progressed through time. If we were to draw a straight trendline from 1981/82 to 2011/12, we would only see the total upward change. We would miss (obscure) all that which happened in between, what led to that total, how (and specifically at what times) the change in temperature took place.

    Blessed with a natural scientific curiosity, we're of course interested in the how and when. We want to investigate the total change a bit closer.

    There are two definite upward shifts to be found along the curve above - one in 1987-88 and one in 1998-99. Do these years sound familiar in any way? In addition, there's one, albeit much smaller, in 2010. Outside of these two (three) pretty eye-catching sudden thrusts, there is no traceable upward trend in the dataset. If anything, there's a hint of the opposite. The entire rise in SST for this vast region from 1981/82 to 2011/12 is to be found in these two (three) particular instances of abrupt elevation of the mean level of anomalies. Without these instances, no general warming. Note how the specific shift events (particularly the first two) put all other up and down fluctuations along the curve to shame. They shoot up like towering pinnacles at the front of each new step.

    I've adapted the graph to visualize the steps:


    The red squares down by the x axis denote the great El Niños that directly preceded the shifts: The double Niño of 1986/87/88, the Super-El Niño of 1997/98 and the globally influential Niño 2009/10 (I have also included the giant El Niño of 1982/83, almost as powerful as the 1997/98 event, but noticeably suppressed globally by the El Chichón eruption).

    Ok. We've now looked at how the SSTA evolved in the world ocean outside the East Pacific through time. It basically all happened in two (three) sudden upward shifts, one in 1987-88 and one through 1998 (+ the minor (and still unresolved) one in 2010).

    Now let's look at how it evolved spatially.

    We split the world ocean into 7 sectors:

    (Sector 1: East Pacific Ocean (65N-60S, 180-80W); Sector 2: West Pacific/East Indian Ocean (65N-60S, 80-180E); Sector 3: North Atlantic Ocean (65N-0, 80W-20E); Sector 4: West Indian Ocean (65N-60S, 20-80E); Sector 5: South Atlantic Ocean (0-60S, 80W-20E); Sector 6: Arctic Ocean (90-65N); Sector 7: Southern Ocean (60-90S). The black rectangle in Sector 1 is the NINO3.4 region. The two black ellipses in Sector 2 mark different definitions of the West Pacific Warm Pool (WPWP). Nevermind those for now.)

    If we area weight the SSTA data for each of these sectors against each other, we come out with something like this:


    This shows the absolute influence each separate sector has on the final global SSTA graph shown at the top of this post.

    It is quite revealing. The Pacific reigns supreme. Not really big news. But still.

    There is something in particular one should note about these graphs. The (NINO) amplitudes of the East Pacific completely overwhelms the amplitudes of all other sectors of the world ocean. No wonder the global graph looks so similar to the East Pacific one, the main difference being the trend. The East Pacific (Sector 1) temperature swings also dwarf those of the West Pacific/East Indian Ocean (Sector 2). Only at two points along the Sector 2 curve above there's a rise that is (nearly) comparable to the amplitudes of Sector 1. These two instances occur in 1987-88 and in 1998-99. Those dates are getting familiar.

    But why is the SSTA evolution of the East Pacific (Sector 1) and the West Pacific/East Indian (Sector 2) so different from one another?

    To understand this, one has to understand how the ENSO process works. More on that in Part 3.

    But first (and rounding off Part 2) let me show you something. What happens if we add the area weighted SSTA data from the other basins outside the East Pacific to the SSTA curve of the West Pacific/East Indian? That is, Sector 2 +3+4+5+6 and 7.

    This is what happens:

    (The lower graph, the blue one, is Sector 2 (West Pacific/East Indian Ocean). The middle graph, the orange one, is Sector 2+3 (The North Atlantic). The upper graph, the pale blue one, is the world ocean outside the East Pacific (65N-60S).)

    Watch how the upward shifts and the steps are simply consolidated going from Sector 2 (West Pacific/East Indian) to global outside Sector 1 (East Pacific).
    Response:

    [DB] If you walk away when a flaw is identified in your analysis then you shouldn't be surprised if others find your argument unconvincing. As you are challenging the mainstream scientific position, the onus is on you to show that your argument is solid. That is the way science works.

    Therefore, you shouldn't ignore the moderator's advice here: "I would recommend that you do not proceed onto part 2 until we have had a chance to digest part 1 and for relevant questions to be answered".

  48. Bob,

    "I assume this is a discussion of the East Pacific data. The appearances are not in question. The trends are."

    The trend is going to be affected by the particular realization of internal variability, particularity since you are looking at a 30 year long trend, any inter-decadal variability will affect the trend. Your observation is "the actual trend differs from the ensemble trend", from which you drew the conclusion that "models are wrong". For your assertion to be valid, you have to show that the discrepancy is larger than what internal variability can account for. You haven't done the necessary step.

    Regarding PDO:


    PDO (regardless the physical cause) is fundamentally a basin-wide mode of variability over inter-decadal timescale.

    In the above the left is the positive phase, while the right is the negative phase.

    You are correct that the most significant change occurs in the northwestern pacific, but there is also a significant component in the eastern pacific as well: the amplitude of the mode is 0.4 degrees for the eastern pacific.

    Furthermore the PDO index went from positive to negative over 1980-2010

    A change of PDO index from 1 to 0 corresponds to a relative cooling of 0.4 degrees over 1982-2010, which is large enough to account of the lack of warming in eastern pacific.

    Your points (a)-(c) ( which you've written about here ) refer to how PDO index relates to the actual temperature anomaly. I don't see the relevance here.

    Your point (d): Is this post the basis of your point? If so, your reasoning is fundamentally flawed, as a correlation does not imply causation, it is equally, if not more, likely that SST anomaly causes a change in air pressue.

    Regarding ENSO:
    Your references all appear to be linear regression analyses, which assume that surface temperature respond proportionally to El Niño and La Niña, which is very different from your assertion in post 40, where you said: "According to numerous peer-reviewed papers, surface temperatures respond proportionally to El Niño and La Niña events, but it’s obvious they do not."
  49. DB (moderator) says: "If you walk away when a flaw is identified in your analysis then you shouldn't be surprised if others find your argument unconvincing. As you are challenging the mainstream scientific position, the onus is on you to show that your argument is solid. That is the way science works."

    What did you have in mind? Where's the flaw?
  50. Could I get a point of clarification?

    Stripping away the forest of verbiage that's sprouted up here and instant treading lightly on brass tacks, is it the claim of Bob Tisdale that there's no trend in global ocean heat content, or if anything that global ocean heat content has in fact decreased as global surface temperature has increased?

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