SkepticalScience Still Misunderstands or Misrepresents the El Niño-Southern Oscillation (ENSO)

The author of the recent SkepticalScience post Distinguishing Between Short-Term Variability and Long-Term Trends, Dana Nuccitelli, still misunderstands or misrepresents El Niño and La Niña processes. Either way, he’s missed something. The instrument temperature record indicates that La Niñas and El Niños serve as a natural recharge-discharge oscillator, with La Niñas acting as the recharge mode and El Niños serving as the discharge and distribution phase. As such, the data indicate that El Niño and La Niña events are responsible for the natural warming of global sea surface temperatures over the past 31 years and that they’re the cause of a portion of the warming of ocean heat content since 1955. If this subject is new to you, refer to my illustrated essay “The Manmade Global Warming Challenge” [42MB]. Also, we’ve discussed time and again that an El Niño-Southern Oscillation (ENSO) index only represents the impacts of ENSO on the variable being measured, and that an ENSO index does not represent all of the ENSO processes or their aftereffects, but the SkepticalScience author Dana Nuccitelli continues to present myths about ENSO indices—and, in turn, about global warming.

I have not read the recent post by Dana Nuccitelli in its entirety. Based on the opening paragraph, it looks to be a comment on the McLean et al (2009) paper Influence of the Southern Oscillation on tropospheric temperature. This post is not a defense of that paper. It’s about the closing statement of Dana Nuccitelli’s post, which is clearly a falsehood. Nuccitelli writes:

If we remove the long-term warming trends, we can see once again that the short-term wiggles in the temperature data are strongly influenced by changes in ENSO. However, the long-term global warming trends are not – they are due to the human-caused greenhouse effect.

Here’s a challenge to Dana Nuccitelli and other bloggers from SkepticalScience. You and your associates at SkepticalScience claim to have analyzed more than 12,000 peer-reviewed papers about global warming and climate change. What I present in the following should be a really easy task, because lower troposphere temperature anomalies for the mid-to-high latitudes of the Northern Hemisphere warmed in a very specific way. Surely, out of the 12,000 papers, a few of them must have addressed how lower troposphere temperatures have actually warmed.

If you believe that manmade greenhouse gases are responsible for the recent bout of global warming, please provide links to the climate model-based, peer-reviewed papers that explain:

1. How and why the lower troposphere temperature anomalies of the mid-latitudes of the Northern Hemisphere show upward shifts in response to strong El Niño events—without proportional cooling during the trailing La Niñas. That is, the RSS lower troposphere temperature anomalies for the latitudes of 20N-90N do not cool proportionally during the La Niña event of 1988/89, Figure 1, but they did warm in response to the 1986/87/88 El Niño, which caused a major portion of the long-term warming trend.

Figure 1

Figure 1

2. And how and why the RSS lower troposphere temperature anomalies for the latitudes of 20N-90N do not cool proportionally during the La Niña event of 1998-01, Figure 2, but they did warm significantly in response to the 1997/98 El Niño, which caused another major portion of the long-term trend.

Figure 2

Figure 2

It is blatantly obvious to anyone reading and comprehending those two graphs that there would be little to no long-term warming of the lower troposphere temperature anomalies for mid-to-high latitudes of the Northern Hemisphere if lower troposphere temperature anomalies had cooled proportionally during the La Niña events of 1988/89 and 1998-01.

I first discussed the warming of lower troposphere temperature data almost 4 years ago in the post RSS Time Latitude Plots Show Climate Responses That Cannot Be Easily Illustrated With Time-Series Graphs Alone. And I discussed why the lower troposphere temperature anomalies for the mid-to-high latitudes of the Northern Hemisphere do not cool proportionally during the 1988/89 and 1998-01 La Niñas in the post The ENSO-Related Variations In Kuroshio-Oyashio Extension (KOE) SST Anomalies And Their Impact On Northern Hemisphere Temperatures.

Back to Nuccitelli’s closing statement: That was the same conclusion reached in a recent video by SkepticalScience, using surface temperatures. I responded to their video with the post The Blatant Errors in the SkepticalScience Video “Global Warming over the Last 16 Years”, which includes the following YouTube video:

DON’T FORGET SEA SURFACE TEMPERATURE AND OCEAN HEAT CONTENT

Further to my challenge to Dana Nuccitelli and his associates at SkepticalScience: if you continue to believe that manmade greenhouse gases are responsible for the recent bout of global warming, please provide links to the climate model-based, peer-reviewed papers that explain how and why sea surface temperature and ocean heat content data have warmed (or not warmed) in the following ways (numbering continued from preceding section):

3. How and why the sea surface temperatures of the East Pacific (90S-90N, 180-80W) haven’t warmed in 31 years (Figure 3).

Figure 3
Figure 3

4. How and why the sea surface temperatures of the Atlantic, Indian and West Pacific Oceans (Figure 4) with the coordinate of 90S-90N, 80W-180, only warmed during the strong El Niño events of 1986/87/88, 1997/98 and 2009/10 and did not cool proportionally during the training La Niñas—and without those El Niño events, the sea surface temperatures there would show no warming.

Figure 4
Figure 4

That should be a simple task since the global oceans were only broken down into two subsets.

Moving now to ocean heat content of the tropical Pacific where the fuel for El Niño events is generated:
5. How and why the warming of the ocean heat content data for the tropical Pacific, Figure 5, is dependent on the 1973-76 and 1995/96 La Niña events, and without those La Niñas the ocean heat content for tropical Pacific would cool.

Figure 5
Figure 5

Still in the subject of ocean heat content:

6. How and why the warming of the ocean heat content of the North Pacific (north of the tropics) is dependent on a 2-year climate shift (1989-90), and without that climate shift, the ocean heat content for the North Pacific would cool (Figure 6).

Figure 6
Figure 6

I discussed the above four graphs and the natural processes that caused their warming in the illustrated essay “The Manmade Global Warming Challenge” [42MB] and in the YouTube video series “The Natural Warming of the Global Oceans” Part 1 and Part 2. And I also discussed them in great detail in my ebook Who Turned on the Heat? which is available in pdf form for only US$8.00. Who Turned on the Heat? also discusses the warming of lower troposphere temperature anomalies shown in Figures 1 and 2.

CLOSING

There’s no reason to wait for links to peer-reviewed papers from Dana Nuccitelli and his associates at SkepticalScience—links that will offer climate model-based explanations for how and why the oceans have warmed in the fashions they’ve warmed and how the lower troposphere temperature anomalies warmed as they had. The warming is dependent on ENSO, and for the ocean heat content of the North Pacific, it depends on a change in wind patterns and sea level pressure. The first problem they’ll encounter is trying to find studies based on climate models that can simulate ENSO. As far as I know, there are a sum total of…How should I put this?…none. See Guilyardi et al (2009), discussed in the post here.

I used the phrases “if you believe” and “if you continue to believe” as part of the challenges to SkepticalScience. Sea surface temperatures, ocean heat content and lower troposphere temperatures have all warmed in very specific ways in response to ENSO. Unless there are climate model-based peer-reviewed papers that explain specifically how and why those variables have actually warmed in the manners in which they’ve warmed as responses to ENSO, then parties like SkepticalScience who are promoting hypothetical manmade global warming are doing so based solely on their beliefs.

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About Bob Tisdale

Research interest: the long-term aftereffects of El Niño and La Nina events on global sea surface temperature and ocean heat content. Author of the ebook Who Turned on the Heat? and regular contributor at WattsUpWithThat.
This entry was posted in ENSO, Lower Troposphere Temperature, Ocean Heat Content, Sea Surface Temperature, Temperature. Bookmark the permalink.

59 Responses to SkepticalScience Still Misunderstands or Misrepresents the El Niño-Southern Oscillation (ENSO)

  1. oldseadog says:

    I haven’t bothered to get in more popcorn – my bet is that they won’t respond.

  2. JJB MKI says:

    Dana Nuccitelli thinks he gets to choose what is a ‘short term wiggle’ and what is a trend. To me, most of his trends are short term wiggles. He also seems to think CO2 somehow saves itself up for very short, intense bursts of climate changing activity. Amazing stuff, CO2. I’m no expert, but it seems that if sea surface temperatures have warmed in the pattern shown as a result of anthropogenic influence rather than asymmetric transport of energy around the ocean basins and to the atmosphere over decadal periods, there must be some serious negative feedbacks at play to prevent warming during ENSO neutral times. What are these Nuccitelli? How can the models tell us anything about them when they cannot reproduce any short term fluctuations? These guys just come out with soap bubble science – it all looks pretty but evaporates into nothing when touched.

  3. Tom says:

    I think I’m missing something here. Sorry if it’s blatantly obvious.

    If ENSO oscillations do not balance out, that is if the cycle results in net warming, then that either represents energy moving from one part of the planet to another (ie oceans to troposphere or some such) or radiative imbalance (ie the earth takes more solar energy in than it re-radiates).

    I haven’t seen anyone suggesting that it’s energy transfer – have I missed this? Is there a theory that ENSO is releasing stored energy into the atmosphere?

    If it’s radiative imbalance, isn’t that global warming? Anthropogenic or otherwise – there’s not enough information there to say why there is a radiative imbalance.

    AFAICT Bob seems to be saying that warming that can be correlated with ENSO “Doesn’t Matter” – which is a technique patented by the Hockey Team, last I checked. But warming is warming, and if it really is net warming then it comes from radiative imbalance – no?

  4. CodeTech says:

    The list of things not understood or misrepresented over there is long and comprehensive, and starts with “Skeptical” and “Science”…

  5. Bob Tisdale says:

    Tom says: “AFAICT Bob seems to be saying that warming that can be correlated with ENSO “Doesn’t Matter” – which is a technique patented by the Hockey Team, last I checked. But warming is warming, and if it really is net warming then it comes from radiative imbalance – no?”

    The difference is that the warming is shown to be natural, and not a result of the increase in manmade greenhouse gas emissions. That is, sea surface temperature data and ocean heat content data show no impact from downward longwave radiation from manmade greenhouse gases. It sounds as though this discussion is new to you, Tom, so if you would, please refer to the following link, which was provided in the body of the post:
    http://bobtisdale.files.wordpress.com/2013/01/the-manmade-global-warming-challenge.pdf
    It provides a pretty good overview.

    Regards

  6. Bob Tisdale says:

    And for those who stopped by my website for the complete monthly sea surface temperature update for April 2013, sorry about the delay. I just posted it:
    http://bobtisdale.wordpress.com/2013/05/07/april-2013-sea-surface-temperature-sst-anomaly-update/
    Yesterday morning, there was a glitch in the data for last week, and I wasn’t sure if that glitch in the weekly data extended over to the monthly data. Sometime in the afternoon, NOAA fixed the problem with the weekly data.

    Regards

  7. wws says:

    You obviously do not have the same Higher Level of Understanding that Mr. Nuctelli has received. What we call “El Nino” is the manifestation of the Male Planetary Essence, and the “La Nina” phenomenon is the outwelling of the Female Essential Spirit. How can it be more obvious? We must throw Gold at them! Showers and showers of Gold, if they are to be appeased! Oh, and please don’t think you can just throw it anywhere. You must first give all of your Gold to Enlightened Beings such as Light Warrior Nucitelli, one of the True High Priests of our age.

    Repent! Repent! Or ye shall all perish in Fire, and Flame, and Nasty, Pointy, Teeth!

  8. Tom says:

    Thanks for the link, it’s very interesting. It does a few things very well, but leaves me with some questions I feel should be really obvious.

    It does really well at showing that climate models are rotten – which I think we all knew pretty well.

    It does really well at explaining the mechanism of the El Nino – La Nina oscillation – that it *is* an oscillation and how heat moves around. I feel like I understand the flows in the oscillation while I only had a vague idea beforehand. Thanks for teaching me something.

    It seems a bit like sleight-of-hand to present graphs with the warming portions of El Nino events removed and to then describe ocean heat content as cooling – after all, you are describing this as a recharge-discharge oscillator, so if you remove the warming bits of the oscillation then *of course* what is left will be cooling. But you say it like it means something, which smells a bit off. I know you’ve not just removed any warming but only the bits that are part of “official” El Nino events, but if you are right and the system is a recharge-discharge oscillator then it amounts to the same thing. You’ve removed the recharge bits and – shockingly! – found that what’s left is an average discharge. To put this another way, how would you respond to someone from the other camp who dismissed all the cooling sections of these graphs as “only caused by La Nina events” and presented a graph that kept stepping upwards – showing that, if you discount the cooling caused by La Nina, warming is even worse than we thought?

    And, lastly, my question I’m left with: If the El Nino – La Nina cycle is a recharge-discharge oscillator, why isn’t it zero-sum? Oscillators either have something driving them, or they average to zero over a long enough course. Why do your graphs show an oscillator that averages to net warming – something that naturally leads to the conclusion that it is an oscillator that is not at its natural equilibrium but one that is being driven up by some external factor?

    I can think of a couple of answers: We might have just got (un)lucky and had several warming cycles in a row by chance. In this case, we ought to expect either zero sum from here on, or perhaps slight cooling to redress the radiative imbalance. Or there might be a longer-term oscillation underlying the immediately apparent oscillation, in which case we should expect accelerating cooling over the coming three or four decades. The current temperature plateau would be consistent with either of these (another method TM the Hockey Team – I’d better watch out) and it’s too early to tell. I’m interested whether you subscribe to one of these theories or whether you have another explanation I’ve missed?

    Thanks for responding!

  9. Tom says:

    I should point out I understand the bit about trade winds and reduced cloud cover – but that’s not an explanation, only moving the problem one step further away. Why have we had an unusual pattern of trade winds and cloud cover that’s persisted for over 50 years? What’s driving the unusual pattern?

    I realise as well that we are getting to the point of trying to discern trends that are much longer than the dataset we have available – so the answer might well be just “we don’t know.”

  10. Réaumur says:

    I have to agree with Tom – there is a lot of interesting information about the details of the El Nino – La Nina oscillation as a transport mechanism, but I also don’t see where the extra energy comes from to cause a net temperature rise.

    Warmists would say that “we” caused it and the oscillations are just moving the result around!

    Please forgive me if I have missed the explanaion in the details, but perhaps others have as well, so it needs to be stated as simply as possible.

  11. Bill_W says:

    Tom,

    As the planet has been warming since the Little Ice Age, the energy is coming from a combination of natural and anthropogenic sources. Since the rate of warming was similar (as a recent Monckton post showed) “from 1976-2001, warming was no greater than in 1860-1880 or 1910-1940″ this would argue that most of it is natural. If now they claim that the heat is hiding in the deep oceans, this would argue for longer lag times so that any affects from man will be muted on very short time scales like 50 years.

    http://wattsupwiththat.com/2013/05/04/monckton-asks-ipcc-for-correction-to-ar4/#comment-1296975

  12. Ed_B says:

    Réaumur says:
    May 7, 2013 at 5:50 am

    I have to agree with Tom – there is a lot of interesting information about the details of the El Nino – La Nina oscillation as a transport mechanism, but I also don’t see where the extra energy comes from to cause a net temperature rise.
    _________________

    That was my first thoughts way back when I first read what Bob was posting. Then I got to think about the fact that the models do not explain why we have warmed since the Little Ice Age.

    Add to that my doubts about the ‘corrections” to the temperature histories.(I trust Central England, which shows nothing alarming at all recently)

    And I conclude that the warming was natural, ie, probablly a result of Sun/planet interactions as per Scafetta, and that Bob Tisdale is quite right, there is no human CO2 signature evident in the records. Just hiccups on the longer term trend. Our CO2 had to ADD to that in a uniformly rising way. It did not.

  13. JohnWho says:

    CodeTech says:

    May 7, 2013 at 4:17 am

    The list of things not understood or misrepresented over there is long and comprehensive, and starts with “Skeptical” and “Science”…

    Agreed.

    An aptly named site, however, since once should be very skeptical of the science there.

    … parties like SkepticalScience who are promoting hypothetical manmade global warming are doing so based solely on their beliefs.

    True dat.

  14. Richard M says:

    One possible answer to the questions raised about the ENSO creation recent warming is the mode of the PDO. For some reason when the PDO is in its cool mode there are fewer El Niño events than when it is in its warm mode. What drives the Pacific ocean to cycle between these modes would be the cause of the cyclic warming and cooling. I’m not aware of any explanations as yet.

  15. Dr. Lurtz says:

    Simple explanation:
    1) Take any Solar Cycle and measure the area under the curve. Convert to Flux [not as noisy ].
    2) Large area under the curve, El Niño will occur. Small area under the curve, La Nina will occur.
    3) Check the strength of the trade winds and the size of the currents leaving Indonesia.
    4) PDO follows as the currents move the warm water to the Northern/Southern Pacific.
    5) Watch the heat leave the Northern/Southern Pacific during a small area under the curve.

    Step 5) is happening now. In about two months, NOAA will declare a La Nina. This will be a great La Nina [very little solar input], and will last a long time.

    The “Great Global Cooling” has been put on hold by this meager Solar Cycle 24. As the Cycle wanes, one should prepare for cold.

  16. _Jim says:

    SkepticalScience: Authors, purveyors of FUD.

    FUD – Fear, Uncertainty and Doubt. Known to be used as a scare tactic, in lieu of logic or cogently expressed ideas and thought, often accomplished by threat (prognosticating imminent doom) or making the opponent doubt his standpoint (through illusion or the presenting of works of outright f raud). A tactic often used in sales, marketing, public relations, politics and propaganda.

    FUD is generally a strategic attempt to influence perception by disseminating negative and dubious or false information.

    One might conclude, therefore, that FUD has _no_ place in science.

    .

  17. Bob Tisdale says:

    Tom says: “It seems a bit like sleight-of-hand to present graphs with the warming portions of El Nino events removed and to then describe ocean heat content as cooling…”

    You’re missing part of the argument. One of the gospels according to the purveyors of the anthropogenic global warming hypothesis is that global temperatures respond proportionally to El Nino and La Nina events. It’s the only way that papers like Foster and Rahmstorf (2011)…
    http://iopscience.iop.org/1748-9326/6/4/044022/pdf/1748-9326_6_4_044022.pdf
    …and Thompson et al (2008)…
    http://www.atmos.colostate.edu/ao/ThompsonPapers/ThompsonWallaceJonesKennedy_JClimate2009.pdf
    …can attempt to remove the impacts of ENSO through linear regression analysis and claim that the remaining warming trend is caused by manmade greenhouse gases.

    And my argument is that they cannot do that because there are residuals from strong El Niño events (leftover warm water) that cause global sea surface temperatures to warm.

    During the satellite era (the last 31 years), only the sea surface temperature anomalies of the East Pacific cool proportionally during La Nina events. Here, let borrow a few illustrations from past posts. Here’s a comparison graph of the sea surface temperature anomalies of the East Pacific compared to NINO3.4 sea surface temperature anomalies, that latter of which is being used as our ENSO index:
    http://bobtisdale.files.wordpress.com/2012/09/figure-111.png

    And here’s a graph of the sea surface temperature anomalies for the rest of the global oceans (the Atlantic, Indian and West Pacific) oceans:
    http://bobtisdale.files.wordpress.com/2012/09/figure-12.png

    Clearly, that dataset does not cool proportionally during La Niñas. To confirm that, we can detrend the Atlantic, Indian and West Pacific data and compare it to our scaled ENSO index:
    http://bobtisdale.files.wordpress.com/2012/09/figure-13.png

    So the warming of the sea surface temperature anomalies for the Atlantic, Indian and West Pacific oceans…
    http://bobtisdale.files.wordpress.com/2012/09/figure-12.png
    …is caused by the failure of the sea surface temperature anomalies to cool proportionally during La Niñas. And the lack of cooling during the La Niñas that follow those strong El Niños results from the warm water that’s left over from the El Niños.

    The above graphs are from the following post:
    http://bobtisdale.wordpress.com/2012/09/20/a-blog-memo-to-kevin-trenberth-ncar/

    I recently carried the illustrations one step farther by removing the warming associated with the specific El Niño events to show that without them there would be no warming:
    http://bobtisdale.files.wordpress.com/2013/05/figure-41.png

    Tom says: “To put this another way, how would you respond to someone from the other camp who dismissed all the cooling sections of these graphs as “only caused by La Nina events” and presented a graph that kept stepping upwards – showing that, if you discount the cooling caused by La Nina, warming is even worse than we thought?”

    They cannot justify doing so. I remove them based on the grounds that if those El Niños had not released the naturally created warm water then those upward steps would not exist.

    Tom says: “And, lastly, my question I’m left with: If the El Nino – La Nina cycle is a recharge-discharge oscillator, why isn’t it zero-sum?”

    Because according to the ocean heat content data for the tropical Pacific it’s not a zero sum. Keep in mind, Tom, that I’m presenting what the data shows. Based on the negative trends in tropical Pacific Ocean Heat Content between the first two 3-year La Niñas of 1954-57 and 1973-76 and between the 1973-76 La Niña and the 1995/96 La Niña …
    http://bobtisdale.files.wordpress.com/2013/01/figure-61.png
    …a typical La Niña that follows an El Niño only replaces part of the warm water released and redistributed by the El Niño—thus the negative trends for those multidecadal periods between them. But the 3-year La Niña events are capable of replacing more ocean heat than was lost over the preceding multidecadal period and that creates the positive trend. Note also in that graph of ocean heat content of the tropical Pacific that the 1995/96 La Niña effectively caused an upward shift in the ocean heat, and the 1998-01 La Niña simply replaced most of the warm water released by the 1997/98 El Niño. Tropical Pacific ocean heat content has cooled since then.

    The last graph is from the following post:
    http://bobtisdale.wordpress.com/2013/01/25/untruths-falsehoods-fabrications-misrepresentations/

    Tom says: “I can think of a couple of answers: We might have just got (un)lucky and had several warming cycles in a row by chance.”

    Bingo. The 1995/96 La Niña was a freak, and when the 1997/98 El Niño released to the surface all of that warm water it created by the 1995/96 La Niña, it effectively raised the sea surface temperatures for the Atlantic, Indian and West Pacific Oceans about 0.19 deg C—and land surface air temperatures and lower troposphere temperatures simply followed suit.

    Tom says: “In this case, we ought to expect either zero sum from here on, or perhaps slight cooling to redress the radiative imbalance.”

    We’ve experienced a cooling of tropical Pacific OHC since the 1998-01 La Niña, but if Mother Nature elects to create another freak La Niña like the one in 1995/96 or another 3-year La Niña like the ones in 1954-57, 1973-76 and 1998-01 then we would expect ocean heat content in the tropical Pacific to warm again.

    Tom says: “I should point out I understand the bit about trade winds and reduced cloud cover – but that’s not an explanation, only moving the problem one step further away.

    Also keep in mind that, due to the reduction of cloud cover, downward longwave radiation (infrared radiation) decreases during La Niñas, while downward shortwave radiation (sunlight) increases. Downward longwave radiation varies in the wrong direction for it to cause the warming. Downward longwave radiation also has another hurdle—it can only penetrate the top few millimeters of the ocean surface and that’s where evaporation takes place.

    Tom says: “Why have we had an unusual pattern of trade winds and cloud cover that’s persisted for over 50 years? What’s driving the unusual pattern?”

    No one knows what drives ENSO. Lots of hypotheses though. ENSO forecasting models still have problems with the springtime prediction barrier, so the ENSO event may be underway (first downwelling or upwelling Kelvin wave) when the models start focusing on the upcoming season. And the models used by the IPCC for hindcasting past and projecting future climate are so pathetic in their modeling efforts that they’re basically useless.

    Regards

  18. Bob Tisdale says:

    Réaumur says: “I have to agree with Tom – there is a lot of interesting information about the details of the El Nino – La Nina oscillation as a transport mechanism, but I also don’t see where the extra energy comes from to cause a net temperature rise.”

    Tropical Pacific cloud cover drops during La Nina events due to the stronger trade winds and resulting cooler sea surface temperatures (less convection, cloud cover and precipitation in the tropical Pacific during La Ninas), and because the stronger trade winds simply push the cloud cover farther west. If there is less cloud cover, there is more sunlight penetrating the tropical Pacific and warming it to depth. On the other hand, less cloud cover means less downward longwave radiation (infrared radiation), so infrared radiation varies in the wrong direction for it to be causing the warming. As I also noted in my reply to Tom above, downward longwave radiation also has another hurdle—it can only penetrate the top few millimeters of the ocean surface and that’s where evaporation takes place.

    Réaumur says: “Warmists would say that “we” caused it and the oscillations are just moving the result around!”

    And as discussed above, they’d be wrong, and the data contradicts their assumptions.

    Regards

  19. Brian says:

    Bob, you continue to post the same idea over and over again. I am starting to get the sense that you are simply promoting your book, since you haven’t provided any new information or ideas in quite a while.

    I agree with Tom and some others that you are just explaining the natural process of ENSO without describing where the warming is coming from. It may be from the same natural processes that brought us out of the little ice age, it may be anthropogenic, or more likely a combination of both. But explaining ENSO to death and creating your own version of the escalator graph does nothing to discredit AGW.

    To be fair, SkepticalScience has also posed questions to you that you have yet to support with peer-reviewed evidence:
    1: Where’s the heat coming from?
    2: What’s the physical mechanism?
    3: Why is this mechanism unidirectional?

    That said, I admire that you have gone to their site to have a civil discussion with them. That’s something I wish they would do more often over here. I believe scientific dialogue is much more beneficial than both you and Nuccitelli repeatedly calling each other’s ideas myths.

  20. Bob Tisdale says:

    Richard M says: “One possible answer to the questions raised about the ENSO creation recent warming is the mode of the PDO. For some reason when the PDO is in its cool mode there are fewer El Niño events than when it is in its warm mode.”

    It’s actually works the other way around. When ENSO is skewed to La Ninas, the PDO tends to be in cool mode, and vice versa when ENSO is skewed to El Ninos. Changes in the sea level pressure of the North Pacific and the resulting wind patterns can also impact the PDO, which is why the PDO’s variations are different that the multidecadal variations of ENSO.

    The sea surface temperatures of the North Pacific of course feed back to the tropics, the North Pacific gyre assures that, but the PDO does not represent the sea surface temperatures of the North Pacific.

    Regards.

  21. Richard M says:

    Bob, thanks for your response. It’s always nice to see someone following the evidence rather than trying to fit it to a preconceived view.

    You say above that you don’t know what drives ENSO modes but then you state that ENSO drives the PDO. Could you articulate a little more on this. Is there actual processes you can follow that demonstrate ENSO is driving the PDO?

    Keep up the good work.

  22. Bob Tisdale says:

    Brian says: “Bob, you continue to post the same idea over and over again.”

    It’s been a long time since I’ve discussed lower troposphere temperature anomalies. So your complaint is unfounded.

    Brian says: “I am starting to get the sense that you are simply promoting your book, since you haven’t provided any new information or ideas in quite a while.”

    Sometimes I include links to my book in posts and other times I don’t.

    Brian says: “I agree with Tom and some others that you are just explaining the natural process of ENSO without describing where the warming is coming from.”

    Actually, if you had read Tom’s comments, he advised that he understood the relationship between cloud cover and trade wind strength in response to ENSO.

    But for you and the others, refer to:
    http://bobtisdale.wordpress.com/2013/01/25/untruths-falsehoods-fabrications-misrepresentations/

    Brian says: “It may be from the same natural processes that brought us out of the little ice age, it may be anthropogenic, or more likely a combination of both. But explaining ENSO to death and creating your own version of the escalator graph does nothing to discredit AGW.”

    Actually, I was first to illustrate the upward shifts in the sea surface temperatures of the Atlantic, Indian and West Pacific oceans. Maybe one of the reasons SkepticalScience created the escalator was to discredit my observations—just maybe.

    Also, if you believe I’m simply repeating myself, then you don’t have to read my posts. Simple as that. But I reach new people each time I discuss ENSO.

    Brian says: “To be fair, SkepticalScience has also posed questions to you that you have yet to support with peer-reviewed evidence:
    “1: Where’s the heat coming from?
    “2: What’s the physical mechanism?
    “3: Why is this mechanism unidirectional?”

    Your and SkepticalScience’s need for peer-reviewed evidence indicates you (plural) cannot read and interpret time-series graphs. I have answered their questions here and at my blog. I answered them repeatedly on the thread you’re discussing, starting at comment 40.
    http://www.skepticalscience.com/argument.php?p=1&t=182&&a=57

    The fact that they didn’t or wouldn’t grasp my answers indicates they weren’t capable of doing so or they were unwilling to.

    While at SkepticalScience, I was confronted with quotes taken out of context and nonsensical comments (if memory serves, some [sarc on] geography major [sarc off] comically tried to say that North America was comparable in surface area to the East Pacific with the coordinates of 90S-90N, 180-80W). Their intent was simply to add confusion for those reading the thread afterwards. Of course I had to waste time and respond to those comments. Then, when bloggers started to repeat or reword questions that I’d already answered, the moderator said that I could not refer the person with the new question to the earlier answer, so I simply cut and pasted the old answer in response to the repeated question. It was clearly a waste of time, and I advised them so. I left. I hadn’t been back until today, when I searched for the link I provided above.

    But I did write the post that answered their questions titled “Untruths, Falsehoods, Fabrications, Misrepresentations” that I had linked earlier in this reply. And here’s a link again:
    http://bobtisdale.wordpress.com/2013/01/25/untruths-falsehoods-fabrications-misrepresentations/

    Brian says: “I believe scientific dialogue is much more beneficial than both you and Nuccitelli repeatedly calling each other’s ideas myths.”

    As far as I know, Nuccitelli has never attempted to discuss ENSO processes in one of his posts. Not once. I’ve only seen him representing ENSO as noise. He may not understand those processes—or, just as likely, he may understand them and has chosen to intentionally mislead his readers.

    Regards

  23. Ed_B says:

    Bob Tisdale says:
    “He may not understand those processes—or, just as likely, he may understand them and has chosen to intentionally mislead his readers.”

    ha.. so true. Nuccitelli can always show up here and post his superiour knowledge and debate those that disagree. What he can’t do is edit WUWT to create a false impression. His failure to show up says that Bobs description is correct. Thats easy enough for everyone to understand.

  24. Bob Tisdale says:

    Richard M says: “You say above that you don’t know what drives ENSO modes but then you state that ENSO drives the PDO. Could you articulate a little more on this. Is there actual processes you can follow that demonstrate ENSO is driving the PDO?”

    Zhang et al (1997) was the first to calculate the PDO:
    http://www.atmos.washington.edu/~david/zwb1997.pdf

    In it, the PDO was identified as “NP”, and they use Cold Tongue region (6S-6N, 180-90W) sea surface temperature anomalies (CT) as the ENSO index. Zhang et al (1997) note:

    “Figure 7 shows the cross-correlation function between CT and each of the other time series in Fig. 5. The lag is barely perceptible for TP and G and it increases to about a season for G – TP and NP, confirming that on the interannual timescale the remote features in the patterns shown in Fig. 6 are occurring in response to the ENSO cycle rather than as an integral part of it…”

    Then there’s Newman et al (2005):
    http://courses.washington.edu/pcc587/readings/newman2003.pdf

    Newman et al (2004) also found that the PDO lags ENSO. They describe cell d of their Figure 1 as:
    “ENSO also leads the PDO index by a few months throughout the year (Fig. 1d), most notably in winter and summer. Simultaneous correlation is lowest in November– March, consistent with Mantua et al. (1997). The lag of maximum correlation ranges from two months in summer (r ~ 0.7) to as much as five months by late winter (r ~ 0.6). During winter and spring, ENSO leads the PDO for well over a year, consistent with reemergence of prior ENSO-forced PDO anomalies. Summer PDO appears to lead ENSO the following winter, but this could be an artifact of the strong persistence of ENSO from summer to winter (r = 0.8), combined with ENSO forcing of the PDO in both summer and winter. Note also that for intervals less than 1yr the lag autocorrelation of the PDO is low when the lag autocorrelation of ENSO (not shown) is also low, through the so-called spring persistence barrier (Torrence and Webster 1998).”

    And the first sentence of the Conclusions of Newman et al (2004) reads:

    “The PDO is dependent upon ENSO on all timescales.”

    Both of those quotes are also presented in the following post about the PDO:
    http://bobtisdale.wordpress.com/2011/06/30/yet-even-more-discussions-about-the-pacific-decadal-oscillation-pdo/

    Regards

  25. There may be nothing new here for Brian but I found the question and answer with Tom clarified a few things for me. A good question and thoughtful answer is why I come here.

  26. Brian says:

    Bob says: “It’s been a long time since I’ve discussed lower troposphere temperature anomalies. So your complaint is unfounded.”

    You have two paragraphs about lower troposphere temperature anomalies, which make the same basic point about step changes resulting from ENSO. The rest of your post in its entirety is regurgitated from your other posts.

    Bob says: “Sometimes I include links to my book in posts and other times I don’t.”

    5 of your last 6 posts (minus the open letter) promote your book. Not that there is anything wrong with promoting your work, but many posts seem to serve only that purpose.

    Bob says: “Actually, if you had read Tom’s comments, he advised that he understood the relationship between cloud cover and trade wind strength in response to ENSO.”

    Yes, he did say that, but it’s a strawman. Nowhere in that statement do I see any reference to a long term net warming trend. I’m not talking about the warming within a single El Nino, I’m talking about the net warming over the last 5 decades or so. Here’s his full comment, which I agree with: “I should point out I understand the bit about trade winds and reduced cloud cover – but that’s not an explanation, only moving the problem one step further away. Why have we had an unusual pattern of trade winds and cloud cover that’s persisted for over 50 years? What’s driving the unusual pattern? I realise as well that we are getting to the point of trying to discern trends that are much longer than the dataset we have available – so the answer might well be just “we don’t know.””

    Regarding your experience at SkepticalScience, I agree that many will attack out of context qoutes and that there is a lot of time wasted correcting uninformed opinions. But there are just as many of those kind of people here, just from the opposite point of view. For instance, Dr. Lurtz above seems to think he can predict a deep prolonged La Nina in two months. Why does that comment get a pass here? So I commend you for arguing your case over there and dealing with those with predetermined conclusions.

    Bob says: “The fact that they didn’t or wouldn’t grasp my answers indicates they weren’t capable of doing so or they were unwilling to.”

    That’s just a ridiculous statement. You seem to imply that anyone who disagrees with what you say is either dumb or stubbornly wrong. I think many commenters there (such as Tom Curtis and KevinC) had legitimate concerns with your hypothesis and methods.

    Bob says: “As far as I know, Nuccitelli has never attempted to discuss ENSO processes in one of his posts. Not once. I’ve only seen him representing ENSO as noise. He may not understand those processes—or, just as likely, he may understand them and has chosen to intentionally mislead his readers.”

    Replace Nuccitelli with yourself, replace ENSO with AGW, and preplace noise with natural. It’s a reversible argument. I don’t believe it is valid from either side.

  27. Larry Kirk says:

    Bob, many thanks for your beautifully clear, understated and articulate explanation of 1. the episodic ENSO oceanic warming process and 2. the absence of any monotonously-rising, industrial CO2-induced warming signal in either the SST or ocean heat content records. Your Global Warming Challenge is a much appreciated education, and a very enjoyable read, which I shall pass on to various associates from either side of the discussion (which here in Australia, is often a very political, opinionated, scientifically ignorant discussion).

    And thanks too to some other commenters and yourself in clearing up the question that was niggling at the back of my mind as I was reading your presentation: “But surely this is showing net warming? And why is that happening right now? And what does it all mean? etc., etc.”

    I can see from your responses that such digressions simply miss your intended point. You are completely aware that there is net warming, it is blindingly obvious, but you don’t pretend to know why, or what longer term pattern that may be part of, and it wasn’t the point of your presentation to address that. You weren’t disputing that there was warming. You were simply showing that the warming couldn’t be due to ‘anthropogenic’ CO2 emissions. All you were intending to demonstrate was the fact that this warming is brought about by clearly understood, completely natural, episodic mechanisms, and that aside from the effects of these, there is no other warming signal in the data. There is certainly no monotonously increasing warming signal of the sort that could possibly correlate with the monotonously rising ‘Keeling Curve’ of trace atmospheric carbon dioxide content.

    (Your description of these natural oceanic warming mechanisms are very thought provoking though. Do we know what ultimately controls the position and strength of the trade winds and how they may have varied over time?)

    I wonder if perhaps some audiences need an additional slide at some point in the Global Warming Challenge, for the numerous influential people that may read it, who will be coming from a position of only superficial familiarity with the subject. Something that clearly informs them that:

    1. ‘Only ocean heat content and temperature measurements count in any consideration of ‘global warming. The heat capacity of the air over the small area of the planet’s surface that is land mass is insignificantly small and is of no consequence. It is barely worth measuring it from a Global Warming perspective’, and

    2. ‘Yes, the data does show that the oceans have warmed overall during the past 30 years of satellite and ocean buoy measurements, but the crucial point is that all of this warming has been due to localised, intermittent and entirely natural oceanic phenomena. If you remove the effects of these natural phenomena from the global data there has been no other warming. So the world is not being warmed by anything else, and not therefore by CO2. It is simply warming naturally, and will eventually also cool again naturally at some point. The climate has always varied like this, throughout geological time and throughout recent history. The earth’s climate is continually variable over time. It is not naturally stable and never has been’.

    As an incidental aside, anybody in search of a perfect small-scale demonstration of the El Nino effect, only has to go swimming here at one of Western Australia’s beaches in the height of summer. We have a west-facing, north-south coastline, and daytime midsummer temperatures in the high 30s to low 40s (C). The ocean is warm enough to swim all year round, and on the hot summer mornings there is an oven-like, dry easterly wind that blows in from the interior. Then in the afternoons, with luck, we get a cooling sea breeze that comes in from the west, cools down the city, and eventually drives everyone off the beach with whipping sand and choppy surf. The thing is though, when you get into the ocean on a day with a strong, hot, offshore easterly wind behind you, it is usually surprisingly chilly, but if there is an early onshore sea breeze you find yourself in warm summer water instead. The easterly winds obviously drive the warm surface water out to sea, and much colder, deeper waters rise up along the shoreline to replace them. Whereas the westerly sea breezes pile up the warm surface waters along the beach for people to enjoy. I don’t know what this summertime diurnal coastal heat pump does to overall coastal water temperatures. I imagine it warms them, as that shallow cold water then spends half the day being warmed by a blazing sun under a cloudless blue sky. But perhaps the late afternoon sea breeze increases evaporative cooling and mixing enough to compensate for the morning’s warming.

    Pardon excessive my late-night rambling!

    With regards,

  28. Janice Moore says:

    Brian, at 0819 on 5/7/13: “Bob, you continue to post the same idea over and over again. I am starting to get the sense that you are simply promoting your book… .”

    Setting aside the fact that, as he pointed out above, Mr. Tisdale has not addressed this particular aspect of his work for some time, there are many people who come to WUWT who, apparently, still do not understand what he is saying. Given that MANY of the above criticisms or questions could easily be answered by reading Mr. Tisdale’s analyses, including his book, he is extremely generous to devote so much of his time to, once again, try to teach what he has learned.

    Bob Tisdale has donated hundreds of hours to teaching on WUWT and essentially GIVEN us all of his work (you don’t need to buy his book) in his many posts and by his patient, thorough, answers. He deserves our unqualified gratitude and praise.

    If you agree that Mr. Tisdale has conferred a substantial benefit on you by his teaching for free, it seems that buying his book, if you can afford it, would simply be the decent thing to do.

    *************************************************************************************

    “… parties like SkepticalScience who are promoting hypothetical manmade global warming are doing so based solely on their beliefs.” [Tisdale]

    Dear Bob Tisdale, you are too generous to the SS gang. They don’t have a sincerely held belief in AGW. They are either prideful to the point of insanity or out for money. The End.

    THANK YOU FOR ALL YOUR FREE TEACHING AND FOR SO GENEROUSLY SHARING YOUR YEARS OF HARD WORK, Mr. Tisdale.

    You are a scientist in the George Washington Carver tradition — the finest tradition.

  29. Crispin in Waterloo says:

    @Bob T

    I really appreciate Figure 4. It is a direct explanation and to me, a proof that the mechanism you have so clearly identified is tangible, quantifiable and validated.

  30. Mac the Knife says:

    Bob Tisdale says:
    May 7, 2013 at 8:07 am
    Tom says: “It seems a bit like sleight-of-hand to present graphs with the warming portions of El Nino events removed and to then describe ocean heat content as cooling…”

    You’re missing part of the argument. One of the gospels according to the purveyors of the anthropogenic global warming hypothesis is that global temperatures respond proportionally to El Nino and La Nina events. It’s the only way that papers like Foster and Rahmstorf (2011)…
    …can attempt to remove the impacts of ENSO through linear regression analysis and claim that the remaining warming trend is caused by manmade greenhouse gases.
    And my argument is that they cannot do that because there are residuals from strong El Niño events (leftover warm water) that cause global sea surface temperatures to warm.

    Bob,
    Thanks for the explanation! I also needed that reminder….
    MtK

  31. A.D. Everard says:

    Thanks you, Bob. You certainly do reach many and there are always new people at WUWT. I have learned a lot through your words.

    As for Brian’s comment about your book, it comes across to me as a deliberate attempt to have readers here question your motives, which frankly makes me question HIS motives. With apologies to Brian if I am wrong, I can’t help but wonder if he is a troll. He seems to be going after the man when he can’t take on the science.

    Brian, if you are not a troll, please stop fretting about whether Bob promotes his book or not. Who cares? Pay attention to the subject matter and keep your questions there, on observations and science. As for Bob’s book, I think it’s excellent that he promote it. He should. It’s the best way to get the information into the hands of the general public in a copy they can own and share. This is hugely important stuff Bob is talking about, and the more people who understand it, the better.

    Cheers.

  32. Sam Yates says:

    Hm. Have you considered that the stepwise progression in global temperatures might simply be the result of applying a quasi-sinusoidal pattern (the oscillating shifts between El Nino and La Nina, in other words) to a continually rising trend in temperatures? During periods where the oscillation was rising, the increase in temperatures would be magnified to produce an apparent leap upwards in temperatures, and during periods when the oscillation was falling the underlying rising trend would more or less cancel out the descent, producing a plateau or a slow descent–which, as it happens, is more or less exactly what is seen in the global temperature record. How would you respond to that criticism?

    On another note, I’d just like to be absolutely sure I understand you; your argument is that, in effect, the extra heat that has accumulated in the Earth system over the past ~50 years has been due to a string of unusually strong La Ninas, which have resulted in an excess of energy (thanks to low cloud cover and a consequent increase in downwelling shortwave radiation) being plonked into the oceans, yes? Or am I misrepresenting that?

  33. Brian says:

    A.D. Everard, I’m certainly not a troll. I have commented on many of Bob’s posts recently, and this is the first time I have said anything at all about the promotion of his book, and it was just one sentence (I’m not exactly fretting about it). In fact, I’m trying to keep the emphasis on the science in a way that is fair to all viewpoints. I have learned a lot from Bob’s explanations of the natural processes of El Nino. And I have made multiple scientific objections, which Bob has answered to various degrees. Perhaps you should pay more attention to the observations and science that I pointed out, and not so much emphasis on one statement I made.

    Personally, I have an issue with making the jump from “ENSO causes the oceans to warm naturally” to “ENSO proves that there is no AGW”. I understand that this is an oversimplification, but I think it’s the essential stripped-down argument Bob is making. By removing El Nino warming (or a lack of La Nina cooling), he is also removing a possible way for AGW to manifest itself. I don’t think this kind of thing would fly in the peer-reviewed literature. Of course a large component of every ENSO cycle is natural, and some warming may be explained by trade winds and cloud cover. But I think Bob has yet to disprove that some degree of the strength of recent El Ninos may be AGW induced warming.

    I think it is very ironic that Bob demands peer-reviewed evidence in this post, and then says this: “Your and SkepticalScience’s need for peer-reviewed evidence indicates you (plural) cannot read and interpret time-series graphs.”

  34. Thanks, Bob.
    I always learn something about ENSO when you share your observations and comments.

  35. phlogiston says:

    Bob, does your delayed oscillator model of ENSO presented in your book agree generally with this mini-review by Fiona Eccles? I confess I still havent read all of the book. I noticed that your thoughts on El Nino and La Nina being discreet events rather than a continuous oscillation receive support from Kessler who also sees interrupted events and intervening neutrality. The key ingredient seems to be intermittency, e.g. Tadokoro et al 2011.

    There is enough knowledge out there on nonlinear/nonequilibrium oscillatory systems in the “chaos” community to really take ENSO by the scruff of the neck and sort it out once and for all. That no-one does this probably is due to political intimidation – if anyone pinned down ENSO in a working intermittent delayed nonlinear oscillator model, they would be accused of supporting AGW “d***ers”, so they are being scared off – only making non-committal statements from afar. This is a depressing state of affairs and shows how AGW thugs like Cook and Nutticelli are holding back science by decades.

  36. Bob Tisdale says:

    Brian says: “You have two paragraphs about lower troposphere temperature anomalies, which make the same basic point about step changes resulting from ENSO.”

    You, Brian, have presented an argument that can easily be found to be wrong by anyone who has read this thread. Specifically, you’re using a time-wasting tactic called misdirection, which is one of the tactics employed by your brethren at SkepticalScience. Excluding the quote from Nuccitelli, out of the first 8 paragraphs, the word troposphere or tropospheric appears in 6. And it appears in the two closing paragraphs.

    Brian says: “The rest of your post in its entirety is regurgitated from your other posts.”

    As I noted earlier, if you believe I’m simply regurgitating cud then why are you bothering to read my posts? Move on. Why are you wasting your time and mine?

    Brian says: “Not that there is anything wrong with promoting your work, but many posts seem to serve only that purpose.”

    If there’s nothing wrong with promoting my book, why are you belaboring this?

    Brian says: “Yes, he did say that, but it’s a strawman.”

    You originally stated and I quoted, “I agree with Tom and some others that you are just explaining the natural process of ENSO without describing where the warming is coming from.” And I replied, “Actually, if you had read Tom’s comments, he advised that he understood the relationship between cloud cover and trade wind strength in response to ENSO”

    The reduction in cloud cover (and the implied increase in sunlight) explains where the energy to warm the water is coming from—or are you intentionally overlooking that? And if you had bothered to read my reply to him, I expanded on the relationship, as I did in my reply to Réaumur. But giving you the benefit of the doubt, my replies to Tom and Réaumur appeared only a few minutes before you posted your original comment, so you may have started writing that comment before I posted my replies and we simply cross paths. Then again, you’re repeating your questions/concerns now—well after I answered Tom and Réaumur.

    Brian says, “Nowhere in that statement do I see any reference to a long term net warming trend. I’m not talking about the warming within a single El Nino, I’m talking about the net warming over the last 5 decades or so.”

    In the numerous posts that, according to you, are regurgitated, I’ve explained the warming of sea surface temperatures during the satellite era (the last 31 years), by discussing multiple strong El Niño events, not “the warming within a single El Nino.” My presentation on ocean heat content for the tropical Pacific extends for 55+ years, and for the ocean heat content, I present multiple La Ninas, so with it we’re definitely not discussing “the warming within a single El Nino.”

    Brian says, “Regarding your experience at SkepticalScience, I agree that many will attack out of context qoutes and that there is a lot of time wasted correcting uninformed opinions. But there are just as many of those kind of people here, just from the opposite point of view. For instance, Dr. Lurtz above seems to think he can predict a deep prolonged La Nina in two months. Why does that comment get a pass here?”

    Because (1) Dr. Lurtz in not complaining about my post, (2) he’s not asking questions, and (3) I haven’t had time to read his comment to see if I want to respond to any portions of it, because I’ve been busy answering questions from a number of bloggers and responding to your continued complaints.

    Brian says: “That’s just a ridiculous statement.”

    Actually it’s not. I presented an opinion. You obviously don’t agree with it, but your disagreement doesn’t make it ridiculous.

    Brian says: “You seem to imply that anyone who disagrees with what you say is either dumb or stubbornly wrong.”

    You appear to be forgetting what I do, Brian. I present data, and I describe what the data presents. I’ve confirmed the processes of El Niño and La Niña events with numerous different datasets in blog posts over the past 4 years—including sea surface temperature, ocean heat content, trade wind strength and direction, cloud amount, downward shortwave radiation, downward longwave radiation, precipitation, lower troposphere temperature, warm water volume, depth averaged temperature of the equatorial Pacific, sea level, sea level pressure, etc.—and I’ve animated maps of most of those datasets and others (like ocean current and direction maps) so that readers could watch the processes of ENSO and the interactions between datasets. Many of the bloggers at SkepticalScience were therefore disagreeing with data, not me.

    And you’ve overlooked another explanation—that I was implying that the bloggers at SkepticalScience refuse to accept the data because it contradicts the hypothesis of CO2-driven human-induced global warming. The telltales of that are the misdirection, fabrications, misinformation, disinformation, etc., the bloggers from SkepticalScience employ when discussing my observations.

    Brian says: “I think many commenters there (such as Tom Curtis and KevinC) had legitimate concerns with your hypothesis and methods.”

    And I responded to their concerns with data. They may not have liked the answers the data provided, but I presented data that answered questions.

    Brian says: “Replace Nuccitelli with yourself, replace ENSO with AGW, and preplace noise with natural. It’s a reversible argument. I don’t believe it is valid from either side.”

    This is the most telling of your comments. It’s not reversible. Over the past 4 years, I’ve presented ENSO processes in minute detail; on the other hand, Nuccitelli presents a wiggly index and calls it ENSO. If you don’t believe my observations are valid, you haven’t bothered to attempt to understand them.

    You, like those at SkepticalScience, would rather try to argue trivialities and provide misleading comments than attempt to understand the somewhat complex interactions between multiple variables. It’s that simple.

    Adios.

  37. Bob Tisdale says:

    phlogiston says: “Bob, does your delayed oscillator model of ENSO presented in your book agree generally with this mini-review by Fiona Eccles?”

    Thanks for the link. Fiona Eccles’s description of the delayed oscillator theory of ENSO (the first paragraph under the section “3 The delayed oscillator”, page 3) agrees with my description, though I went into more detail in my chapter 4.9 in an attempt to make it easier for those without technical backgrounds to understand. The description from the following IRI webpage also agrees.
    http://iri.columbia.edu/climate/ENSO/theory/index.html

    phlogiston says: “This is a depressing state of affairs and shows how AGW thugs like Cook and Nutticelli are holding back science by decades.”

    Cook and Nuccitelli simply parrot the findings of the mainstream climate science community. It’s the scientists/modelers/statisticians who have either failed to examine and understand ENSO or they’re intentionally misrepresenting it. I would prefer to believe the former—that they’ve simply overlooked it because they couldn’t model it. On the bright side, according to one of the lead authors of the upcoming IPCC AR5:

    “Yes there is a need to do more on improving ENSO, and indeed this will help improve the ability to forecast regional climate variability on season to decadal timescales and beyond. Again this is an area where there is a lot of research going on at the moment.”

    See my exchange with Richard Betts here:
    http://tallbloke.wordpress.com/2013/01/05/major-change-in-uk-met-office-global-warming-forecast/comment-page-1/#comment-40242

    Regards

  38. Bob Tisdale says:

    Brian says: “Personally, I have an issue with making the jump from ‘ENSO causes the oceans to warm naturally’ to ‘ENSO proves that there is no AGW’. I understand that this is an oversimplification, but I think it’s the essential stripped-down argument Bob is making.”

    You’ve personally made a jump that I don’t make. I state that there is no evidence that manmade greenhouse gases have had any impact on the warming of the global oceans. That is not the same as “ENSO proves that there is no AGW”. In fact, in my videos and essays I present the multiple anthropogenic factors that cause land surface temperatures to warm above and beyond the warming there caused by the natural warming of the oceans–including but not limited to the increased emissions of manmade greenhouse gases.

  39. Bob Tisdale says:

    Sam Yates says: “Hm. Have you considered that the stepwise progression in global temperatures might simply be the result of applying a quasi-sinusoidal pattern (the oscillating shifts between El Nino and La Nina, in other words) to a continually rising trend in temperatures?”

    Yes, that’s the basic argument made by those promoting the hypothesis of human-induced global warming. They claim that ENSO is simply noise overlaid on top of the global warming signal. That hypothesis fails to account for the naturally created warm water released and redistributed by strong El Nino events. That warm water is reason for the long-term trend in global sea surface temperatures during the satellite era, not greenhouse gases. For a quick overview, refer to the YouTube video linked in the post…

    …and to the essay;
    http://bobtisdale.files.wordpress.com/2013/01/the-manmade-global-warming-challenge.pdf

    Regards

  40. Bob Tisdale says:

    Mac the Knife says: “Thanks for the explanation! I also needed that reminder….”

    And that means I need to include that reminder when I present those graphs.

    Thanks.

  41. Brian says:

    Bob, in your lengthy hypocritical response, I don’t think you have really answered any of my concerns. You quote me, then twist my words into something that you can easily rebut, thereby arguing against something different from what I actually said. I would explain each (and I will if anyone would like), but I’m sure you’ll just say I’m using “time-wasting tactics”. So I’ll sum up my major concerns succinctly in a few lines:

    1. No one is disputing your data or observations. Myself and others have disputed the conclusions that you draw from the data (that ENSO can explain away AGW).

    2. Reduced cloud cover is one of the causes of each step change. You have yet to explain why there have been more steps up in temperature, creating a decades-long net warm trend.

    3. Removing El Nino from a temperature plot is misleading, as it removes a possible mechanism for AGW to manifest itself.

    4. Your hypothesis has not been reviewed by scientists. The following statement casts considerable doubt on it, especially given your demands for peer-reviewed evidence in this post: “Your and SkepticalScience’s need for peer-reviewed evidence indicates you (plural) cannot read and interpret time-series graphs.”

    These are major concerns, not trivialities.

  42. Brian says:

    Bob, you have a problem with my statement “‘ENSO proves that there is no AGW’. I understand that this is an oversimplification, but I think it’s the essential stripped-down argument Bob is making.”

    Then you say this:

    “They claim that ENSO is simply noise overlaid on top of the global warming signal. That hypothesis fails to account for the naturally created warm water released and redistributed by strong El Nino events. That warm water is reason for the long-term trend in global sea surface temperatures during the satellite era, not greenhouse gases.”

    So you seem to admit there may be an AGW signal over land, but absolutely not in sea surface temperatures. Fine, that’s part of the oversimplification I was referring to. It doesn’t change what I was saying whatsoever, but that’s the only sentence you responded to. How can you accuse me of belaboring trivialities when you continually skip the main components of my arguments?

    Here’s my comment again with your trivial complaint corrected:

    Personally, I have an issue with making the jump from “ENSO causes the oceans to warm naturally” to “ENSO proves that there is no GHG signal in the satellite era SST trends”. I understand that this is an oversimplification, but I think it’s the essential stripped-down argument Bob is making. By removing El Nino warming (or a lack of La Nina cooling), he is also removing a possible way for AGW to manifest itself. I don’t think this kind of thing would fly in the peer-reviewed literature. Of course a large component of every ENSO cycle is natural, and some warming may be explained by trade winds and cloud cover. But I think Bob has yet to disprove that some degree of the strength of recent El Ninos may be AGW induced warming.

    I think it is very ironic that Bob demands peer-reviewed evidence in this post, and then says this: “Your and SkepticalScience’s need for peer-reviewed evidence indicates you (plural) cannot read and interpret time-series graphs.”

  43. Skiphil says:

    FYI, Roger Pielke, Sr. with lengthy comment at Climate Etc. (the full text of his email to David Appell):

    http://judithcurry.com/2013/05/07/more-on-the-pause/#comment-319450

  44. Ed_B says:

    Brian, you are a troll. Bob answered you straw man statement with:

    “You’ve personally made a jump that I don’t make. I state that there is no evidence that manmade greenhouse gases have had any impact on the warming of the global oceans. That is not the same as “ENSO proves that there is no AGW”. In fact, in my videos and essays I present the multiple anthropogenic factors that cause land surface temperatures to warm above and beyond the warming there caused by the natural warming of the oceans–including but not limited to the increased emissions of manmade greenhouse gases”

  45. Theo Goodwin says:

    Brian says:
    May 7, 2013 at 2:04 pm
    “A.D. Everard, I’m certainly not a troll.”

    Actually, Brian, you are a Troll. However, I will explain your (pretended) misunderstanding of Mr. Tisdale’s work.

    In writing about ENSO, Mr. Tisdale uses the published data about ENSO in an effort to describe the natural processes that make up ENSO. That is what he is doing. He sticks to the observations. He has never offered a scientific explanation for ENSO.

    His work is not intended as a direct criticism of AGW or Alarmist climate science. However, his work is a powerful indirect indictment of Alarmist climate science because it shows that ENSO does consist of natural processes that have been described to some extent. Because he is not a rich institution, he has not found all the natural processes that make up ENSO and he has not followed any natural process to its ultimate cause. As you no doubt know, Alarmist climate science does not treat ENSO as a natural process at all. In fact, they deny that it is a natural process.

    Mr. Tisdale might seem to repeat himself because such repetition is the very nature of describing natural processes as one’s knowledge of the process is growing and being refined.

    When you ask him for causes or explanations, you show that you have not a clue what he is doing or what he has achieved in his work. When you berate him for not answering your questions about causes or explanations, you are simply compounding your error.

  46. Crispin in Waterloo says:

    Brian

    I don’t think you’re a troll but I am pretty sure you have no intention of accepting the conclusions of any argument or sets of data that contradict the idea that the warming, stepped or not, depending on how you wish to draw the trend lines, is not primarily caused by AGW. It is clear though all your posts that you are scurrying around the essential arguments looking for a way to hide AGW behind every tree and I am getting tired of reading it. You are being out-classed.

    For your putative ‘AGW signal in the ENSO warming’ or AGW from CO2 to be a large contributor to long term warming (I noted your very carefully worded #2 above so don’t think we are not considering your statements carefully) you will have to provide some alternative explanation for the warming that has something to do with CO2. Central to this need is some mechanism for CO2 to heat the oceans. How on earth do you explain that back-radiation is going to heat the oceans?

    I know there is no such mechanism because the physics are dead set against it. So, what does that leave? It leaves you a very weak argument that somehow warmer air is damping the heat loss from a natural ENSO heating event and the result is a ‘stronger El Nino’. Poppycock, I say.

    If such a mechanism existed, and it was primary caused by AGW induced by CO2, there would be a continuous influence that would smooth the rise along with the CO2. There is clearly no such rise in the data. It is a stepped signal and it only steps up with solar-induced El Nino events. I expect some rebuttal from you about ocean heat content and yatta yatta about how it could be happening in some as-yet-undiscovered cyclical way in which ocean heat content is driven up (again by either having back-radiation heat the oceans or limiting heat loss) that just happens to match the rather obvious El Nino heating. Well, it could be a large number of mice running on tiny treadmills connected to friction brakes with water cooling systems connected to the ocean floor. Or not.

    I find Bob’s rather specific complaints about the poor quality of discussion at SkS to be believable. The main points Bob makes are well documented, well presented and alternative explanations are, so far, simply not viable – make that ‘not believable’. I think your treatment of him here is shabby and poorly intended, perhaps for an external audience that is not contributing at all. I find your analyses intent only on showing that he has not shown that AGW is disproved. To what end? If you understand this subject so well, why not just present your view on how the data shows that CO2 can create step-wise increases is ocean temperatures so we have an alternative to consider?

    After you do that, you can write to SkS and point out that the single-slope-trendline graph is bunk, not because the very real ‘stepped’ nature of ocean heat content is caused by El Nino events, but because it is actually caused by your newly discovered CO2-related mechanism with its clear tie to human emissions of fossil CO2. Until then I encourage to adopt a silent key approach to this subject. As Victor Borge so wisely said, “If you have nothing to say, the least you can do is shut up.”

  47. Brian says:

    I’ll respond somewhat briefly, as I don’t want these discussions to become overly verbose and lose sight of the science. Still, I would like to try to respond to each poster who addresses me.

    Theo, I have never said that Bob offers an explanation for ENSO, but he certainly does claim that his observations indicate that there is no GHG signal in the oceans. This is a claim, more than just showing data. I understand that he doesn’t have substantial resources to work with, but he is putting his work out there on a widely read blog, and I think he handles rebuttals quite well. He very rarely resorts to ad hominem attacks, and does a great job of answering many comments. Overall, I have great respect for Bob and his work. I don’t think I am berating him, but rather giving point by point responses in civilized dialogue.

    Crispin, you have come to the conclusion that I subscribe to CAGW, or that I’m some sort of SkS crony. I am neither of those. I’m in the camp that says we don’t know nearly enough about climate yet to either prove or disprove the precise impact of any possible forcing. As such, your first 4 paragraphs are generally falling on deaf ears for me. You do make a very valid point when you say “I find your analyses intent only on showing that he has not shown that AGW is disproved. To what end?” I suppose it is because many commenters here seem to think that Bob has indeed disproved AGW, and there are very few dissenting opinions. I think dissenting opinions are necessary to avoid confirmation bias. Believe me, I don’t like the way SkS handles dissent either. They will fit any forcing imaginable into their GHG framework without acknowledging any shortcomings.

    Looking back, I see that I got off on the wrong foot by (unintentionally strongly) accusing Bob of self-promotion. Bob, I apologize for that, and I appreciate that you respond to rather than ignore criticism..

  48. Pierre-Normand says:

    The paper: Pavlakis et al. (2008) “ENSO surface shortwave radiation forcing over the tropical Pacific”, referred to by Bob Tisdale, is quite interesting. I was unaware of this cloud induced amplification of the ENSO induced effect on ocean heat content.
    This paper (Pav. 2008) also refers to their earlier Pavlakis et al. (2007) “ENSO surface longwave radiation forcing over the tropical Pacific” where they present evidence for longwave forcing about twice as large as the shortwave forcing. This forcing is partly caused by the SST variation between La Nina and El Nino. They define NSL (the net surface longwave downwelling) as the difference between the downward longwave radiation (DLR) and the surface thermal emission. This latter term is εσT^4. The variation of that term accounts for much of the La Nina induced forcing (and the corresponding El Nino dampening). (See figure 7 in the paper; available online).
    Bob Tisdale makes no mention of this longwave forcing, but it seems that it could potentially change the strength of his La Nina ‘recharge’ mechanism. He seems to be dismissing such effects on the ground that longwave radiation can’t penetrate much beyond the ocean skin layer. However, if the effect of this forcing merely is to slowdown the rate of longwave surface cooling that compensates the rate of (deeper) shortwave warming, then this objection is irrelevant. (This objection was put to some Sky Dragon Slayer, and I can’t remember hearing a convincing response). Second, it doesn’t seem to me that an increase in latent heat flux can neutralize this forcing (as Bob Tisdale suggested it could). There are both a theoretical and an empirical objection to this proposal. The theoretical objection is that the forcing can hardly cause a large increase in the latent heat flux when the air above the surface already is saturated (or nearly saturated) with water vapor. The empirical objection is that the sensible heat flux actually seems larger over much of the Tropical Pacific during the El Nino phase of ENSO than it is in the La Nina phase. I am wrong about this?

  49. Bob Tisdale says:

    Brian says: “Personally, I have an issue with making the jump from ‘ENSO causes the oceans to warm naturally’ to ‘ENSO proves that there is no GHG signal in the satellite era SST trends’. I understand that this is an oversimplification, but I think it’s the essential stripped-down argument Bob is making. By removing El Nino warming (or a lack of La Nina cooling), he is also removing a possible way for AGW to manifest itself.”

    Then you’ll have to wait around until climate models can simulate ENSO properly. Until they can, there is no way to even suggest that manmade greenhouse gases have had any impact on the warming of sea surface temperatures and ocean heat content.

    Brian, you’re overlooking the obvious. According to IPCC, only anthropogenic forcings can explain the warming over the past 30 years:
    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-9-5.html

    The assumption there is that the climate models simulate natural ocean-atmosphere processes. But it’s well known that climate models don’t. In fact, ENSO is neutered in most climate models, meaning ENSO in models is skewed to zero (El Niños and La Niñas balance out over multidecadal periods), so that ENSO cannot contribute to the warming or cooling.

    Then there are studies like Foster and Rahmstorf (2011)…
    http://iopscience.iop.org/1748-9326/6/4/044022/pdf/1748-9326_6_4_044022.pdf
    …and Thompson et al (2008)…
    http://www.atmos.colostate.edu/ao/ThompsonPapers/ThompsonWallaceJonesKennedy_JClimate2009.pdf
    … that continue the myths about ENSO and attempt (and fail) to remove the impacts of ENSO through linear regression analysis and then claim that the remaining warming trend is caused by manmade greenhouse gases.

    I’ll repeat now what I wrote to Tom:
    And my argument is that they cannot do that because there are residuals from strong El Niño events (leftover warm water) that cause global sea surface temperatures to warm.

    During the satellite era (the last 31 years), only the sea surface temperature anomalies of the East Pacific cool proportionally during La Nina events. Here, let borrow a few illustrations from past posts. Here’s a comparison graph of the sea surface temperature anomalies of the East Pacific compared to NINO3.4 sea surface temperature anomalies, that latter of which is being used as our ENSO index:
    http://bobtisdale.files.wordpress.com/2012/09/figure-111.png

    And here’s a graph of the sea surface temperature anomalies for the rest of the global oceans (the Atlantic, Indian and West Pacific) oceans:
    http://bobtisdale.files.wordpress.com/2012/09/figure-12.png

    Clearly, that dataset does not cool proportionally during La Niñas. To confirm that, we can detrend the Atlantic, Indian and West Pacific data and compare it to our scaled ENSO index:
    http://bobtisdale.files.wordpress.com/2012/09/figure-13.png

    So the warming of the sea surface temperature anomalies for the Atlantic, Indian and West Pacific oceans…
    http://bobtisdale.files.wordpress.com/2012/09/figure-12.png
    …is caused by the failure of the sea surface temperature anomalies to cool proportionally during La Niñas. And the lack of cooling during the La Niñas that follow those strong El Niños results from the warm water that’s left over from the El Niños.

    Now, Brian, how do we know that leftover warm water exists?

    Because we can see it. It’s there. It exists. For example, the leftover warm waters can be seen in the following sea level animation from the Jet Propulsion Laboratory. The Rossby wave appears just west of Central America at about 10N, right after the peak of the 1997/98 El Niño. And the Rossby wave carries the warm leftover warm water back to the western tropical Pacific, where there then appears to be a secondary El Niño event taking place in the northwestern tropical Pacific, while the La Niña is taking place in the eastern tropical Pacific:
    http://bobtisdale.files.wordpress.com/2012/06/animation-3-1.gif

    All of that leftover warm water in the western tropical Pacific is redistributed with time, but it also counteracts the effects of the 1998-01 La Niña on land surface temperatures and on remote ocean basins like the North Atlantic.

    Do studies like Foster and Rahmstorf (2011) and Thompson et al (2008) account for that easy-to-see leftover warm water? No!

    Brian says: “I don’t think this kind of thing would fly in the peer-reviewed literature.”

    It’s not intended for peer-reviewed literature. It’s intended for consumption the general public who can read and interpret time series graphs and who can look at an animation and understand how we know the leftover warm water exists. The climate science community would never think of changing their mindset unless the general public understands the flaws in the hypothesis of manmade global warming and insists the climate science community cleans up its act.

    Brian says: “Of course a large component of every ENSO cycle is natural, and some warming may be explained by trade winds and cloud cover. But I think Bob has yet to disprove that some degree of the strength of recent El Ninos may be AGW induced warming.”

    Refer to the abstract of Ray and Giese (2012) Historical changes in El Niño and La Niña characteristics in an ocean reanalysis:
    http://onlinelibrary.wiley.com/doi/10.1029/2012JC008031/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false

    Their abstract ends with:
    “Overall, there is no evidence that there are changes in the strength, frequency, duration, location or direction of propagation of El Niño and La Niña anomalies caused by global warming during the period from 1871 to 2008.”

    Brian says: “I think it is very ironic that Bob demands peer-reviewed evidence in this post, and then says this: ‘Your and SkepticalScience’s need for peer-reviewed evidence indicates you (plural) cannot read and interpret time-series graphs.’”

    Once again, you miss the obvious. You asked me for peer-reviewed literature earlier in the thread, and the bloggers at SkepticalScience will accept a discussion of data only if it appears in peer-reviewed literature. Yet, you as a group can’t provide peer-reviewed papers that explain how and why the oceans (sea surface temperatures and ocean heat content) warmed in the fashions in which they’ve warmed. That’s why I asked in the post. That’s the irony.

    Regards.

  50. Bob Tisdale says:

    Pierre-Normand, regarding Pavlakis et al. (2007) “ENSO surface longwave radiation forcing over the tropical Pacific”:

    I haven’t overlooked it. Please note the sign of the variations in downward longwave radiation for eastern and central tropical Pacific . Downward longwave radiation increases during El Ninos and decreases during La Ninas. In order for downward longwave radiation to contribute to the recharge of ocean heat during La Ninas, it would have to increase, not decrease. Downward longwave radiation may increase during El Ninos, but the tropical Pacific is releasing heat then.

    Then again, downward longwave radiation has the other hurdle–it can only penetrate the top few millimeters of the ocean surface (where heat is released through evaporation), while downward shortwave radiation (sunlight) penetrates to depth. Even if we assume the majority of the sunlight is absorbed in the top 10 meters, it’s contribution is many orders of magnitude greater than any of the effects of infrared radiation that remain after the loses through evaporation.

    Regards

  51. Pierre-Normand says:

    I wrote “I am wrong about this?”
    Having done some more research, it seems I may have been mislead by a graph. The latent heat flux likely is larger during La Nina episodes. Please, disregard this specific objection.

  52. Brian says:

    Bob says: “Until they can, there is no way to even suggest that manmade greenhouse gases have had any impact on the warming of sea surface temperatures and ocean heat content.
    Brian, you’re overlooking the obvious. According to IPCC, only anthropogenic forcings can explain the warming over the past 30 years:”

    I’m not sure why you boil this down to such a black and white issue. I do not believe that ocean warming can only be due to anthropogenic forcings. I believe that almost any forcing can be suggested at this point, but none have been proved. I am not arguing in favor of Foster and Rahmstorf, Thompson, SkS, the IPCC, or any CAGW agenda. You are wasting your own time by lumping me in with them. In your extremely lengthy response, you have directly answered one of my four major concerns, about peer-reviewed evidence. I don’t agree with your answer, but you certainly cleared up your stance on the issue. Thanks for that. I will no longer bring up that point.

    Here are the other thee that remain unaddressed:

    1. No one is disputing your data or observations. Myself and others have disputed the conclusions that you draw from the data (that ENSO can explain away AGW in the oceans).

    2. Reduced cloud cover is one of the causes of each step change. You have yet to explain why there have been more steps up in temperature, creating a decades-long net warm trend.

    3. Removing El Nino from a temperature plot is misleading, as it removes a possible mechanism for AGW to manifest itself.

    You can talk about warm water that models don’t account for all day long. I’m not discussing AGW models here, only you are. There is a huge difference between saying models are not accounting for natural ENSO warming, and saying that there is no way to suggest any GHG forcing in the oceans.

    The Ray and Giese paper is a good start. I’m unsure how to interpret the last sentence of their abstract, since earlier they say “As has been previously shown for the strength and location of ENSO there is little overall trend in the characteristics.” So if they are saying there is no ENSO trend regardless, that seems to go against your hypothesis. They could be implying that warming is seen in the oceans without affecting ENSO over the long term. I don’t have access to the paper though, so I don’t know what they are really trying to say. Are there any others you know of that deal with this?

  53. Matthew R Marler says:

    It is blatantly obvious to anyone reading and comprehending those two graphs that there would be little to no long-term warming of the lower troposphere temperature anomalies for mid-to-high latitudes of the Northern Hemisphere if lower troposphere temperature anomalies had cooled proportionally during the La Niña events of 1988/89 and 1998-01.

    What’s your point? Accumulated CO2 prevents the La Niña event from cooling after facilitating El Niño warming? I wouldn’t say that it does, but I do not think that your data rule it out.

  54. Bob Tisdale says:

    Matthew R Marler says: “What’s your point? Accumulated CO2 prevents the La Niña event from cooling after facilitating El Niño warming?”

    I’m not sure how you could jump to that conclusion. Just the opposite. The paragraph you quoted was followed by one that discussed two prior posts about TLT data. The second link included a detailed discussion that basically boils down to the leftover warm water from the 1986/87/88 and 1997/98 El Niño events counteract the effects of the trailing La Niñas and keeps the lower troposphere temperature anomalies of the mid-to-high latitudes Northern Hemisphere from cooling during those La Niñas.

  55. Bob Tisdale says:

    Brian, are you aware that there is no long-term warming trend in the sea surface temperature anomalies of the eastern equatorial Pacific?
    http://oi46.tinypic.com/11s36ua.jpg

    Are you aware that, even though there is no long-term trend, there is a decadal/multidecadal component to ENSO?
    http://i43.tinypic.com/33agh3c.jpg

    If CO2 was driving the El Nino dominated period, why have NINO3.4 sea surface temperature anomalies turned back to La Nina conditions?

  56. Pierre-Normand says:

    Bob, when you speak of the “leftover warm water” for an El Niño even, do you mean to refer (1) to an active area where the SST anomaly remains high (down to the thermocline) on account of some active ocean/atmosphere dynamical heat transfer process, or continuous forcing, or (2) do you rather mean to refer to the simple release of the accumulated heat in the warm pool? In other words, do the “events … counteracting the effects of the trailing La Niña” come from some dynamical process that provides a continuous source of energy, or is the energy simply a release of the energy previously accumulated in surface waters over the preceding ENSO phases? It sounds like you mean the latter, but I’d like to be sure. If it’s the case, did you compute if the amount of thermal energy in that pool might be sufficient to counteract the effects of the La Niña while SST might still remain quite high over the area of the warm pool?

  57. Brian says:

    Yes, Bob, I’m aware of both of those things, as I have been following your posts for a while. I have learned much about ENSO, PDO, and AMO, none of which discredit the fact that there may be a GHG forcing component in the warming of the oceans as a whole. Again you make this a black and white issue with your last question. I never said CO2 was driving anything. I said that it may be one component of the overall warming trend, possibly manifested by strong El Ninos.

    You still aren’t answering any of my major concerns. Please stop using time-wasting tactics.

  58. matt says:

    “If CO2 was driving the El Nino dominated period, why have NINO3.4 sea surface temperature anomalies turned back to La Nina conditions?”

    Whether it is correct or not, there is a theory about this called the dynamical thermostat. See for example Clement et al. 1996, Journal of Climate. FWIW, paleoclimate reconstructions of Nino3.4 also seem to suggest an anticorrelation between the cold tongue and ~200-yr solar cycle (Emile-Geay et al 2013, also J. Climate). Also fwiw, the Hadley SSTs show 20th century warming everywhere except a piece of the North Atlantic and One effect of this is to increase the east-west temperature gradient on the equator which maybe could strengthen El Nino events. Still a *lot* of uncertainty in all this, and it’s fairly controversial even within the climate community (more researchers argue an opposite mechanism, in fact), but it is at least consistent.

    BTW, my paper is 2003.

  59. matt says:

    Hmm, that line should be “Also fwiw, the Hadley SSTs show 20th century warming everywhere except a piece of the North Atlantic and the cold tongue region.”

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