Response to Willis Eschenbach’s WUWT Post “How The El Nino Is Changing” 

UPDATE 12/14/22: I replaced the illustrations of the 7 graphs I created for this post, to reflect the correction of a glitch in my spreadsheet that impacted one month. The correction had no effect on the content of the post or the trendlines illustrated.

. . .

Does the start date of Willis Eschenbach’s comparison graph, his Figure 5 (my Figure 1 below), in his recent post at WattsUpWithThat titled “How The El Nino Is Changing”, impact the trends toward La Niña conditions? Answer: Yes. A 9-year earlier start date flattens the trends.


Initial Note: The title of Willis’s recent post at WUWT caught my interest, because it was ENSO related. As you may recall, back when I was blogging regularly, for many years, I wrote many dozens of posts that were cross-posted at WUWT about the El Niño Southern Oscillation, and the coupled ocean-atmosphere processes that drive El Niño and La Niña events, and the aftereffects of those events. In Willis’s post, I was hoping to find analyses and documentation of ENSO coupled ocean-atmosphere processes to show how those were changing. But what did I find? A comparison graph of ENSO indices with linear trends and a curious start date.

So, with that in mind, let’s take a look at that comparison graph, Willis’s Figure 5, which I’ve included as my Figure 1, below. His caption for that comparison graph reads,“Figure 5. LOWESS smooths of four El Nino indices, along with their straight-line trends. El Niño conditions are more positive, La Nina conditions are more negative.”

Figure 1

First: When I was blogging regularly, I had been examining, preparing, and posting graphs of ENSO indices for many years so the first thing that stood out to me was the start year, just before the 1980 hashmark. That caught the attention of at least one other person commenting on the post at WUWT, because most ENSO indices include many decades of data prior to 1980. See the comment by Richard M here and my comment here. Willis’s response to those comments about the start year was that he wanted to include the newest ENSO index, the Multivariate ENSO Index (MEI), and that its data began in 1979.

Second: Notice in Willis’s graph that color-coded index for the curve and trend for the Southern Oscillation Index data is incorrectly identified as the “Southern Ocean Index”. Also note a second typo. NOAA has a NINO3.4 Index, not a NINO34 Index.

Third: Willis has inverted the off-equatorial Southern Oscillation Index (SOI) data. Normally, Southern Oscillation Index (SOI) data is presented without being inverted so that El Niño spikes are downward and La Niña spikes are upward, which is the opposite of how they appear with the other indices. Of course, he inverted the SOI data so that he could include that off-equatorial ENSO index in his comparison graph.

Fourth: Following his Figure 5, Willis states in the text of his post:

“You can see the peaks representing the big El Ninos around 1997-98 and 2015-16. Recall that according to my thermoregulatory hypothesis, the Pacific should be trending towards a more La Nina condition which is more negative.
“And all four indices, in varying amounts, show this exact outcome—in response to the slow gradual warming since 1980, we have more La Nina conditions cooling the planet.”

I had never heard of Willis’s “thermoregulatory hypothesis” prior to reading his recent post (linked above). Therefore, it will be up to you readers to comment on whether the flattening of the trend lines when the data for the ENSO indices starts in 1970, as shown in the graphs below, has any impact on his “thermoregulatory hypothesis”. I also have a question for you readers about the above quoted paragraphs from Willis’s post. Why did he identify the strong 1997/98 and 2015/16 El Niños, but not the strong El Niño of 1982/83, or the strong one of 1987/88 (portion of the 1986/87/88 El Niño), or the strong 1991/92 El Niño? Those other three El Niño events all exceeded NOAA’s +1.5 deg C threshold for a strong El Niño.

Fifth, regarding the start year of Willis’s graph, I stated in a comment on that WUWT thread that the 1980 (1979) start year was curious, considering that it was a few years prior to the strong 1982/83 El Niño. Further on that thread, I suggested to Willis that he exclude the data for the Multivariate ENSO Index (MEI) and he start a set of reference graphs in 1970 to include the La Niña dominant early-to-mid 1970s in an effort to see what happened to the trends. I advised him that I would present them, if he chose not to. He chose not to, as far as I know, so I did. They follow.

So, let’s start the presentation.


The following three pairs of time series graphs are provided to show the easily discernable flattening of the trend lines when the start date for the ENSO index graphs is changed from 1979 (used by Willis Eschenbach in his post at WUWT) to 1970. In the graphs starting in 1970, the strong 1972/73 El Niño and the three La Niña events (one moderate, two strong) in the early-to-mid 1970s really stand out in the graphs of the ONI and NINO3.4 data…not so much in the SOI data.

Why did I use 1970 as the start year? The early to mid 1970s are dominated by La Niña events, as are the most recent years. In other words, with the 1970 start year, the graph starts and ends in periods dominated by La Niña events, making it difficult for anyone to accuse me of cherry picking the start year.

I didn’t use any smoothing on the data in the graphs. That would reduce the magnitude of the ENSO variations and make the trends appear greater by comparison. Additionally, as I presented the data for each index individually, there was no need to standardize the data. As a result, the graphs are of data as provided by the suppliers, which are linked in the following discussions.


Figures 2a and 2b present the unsmoothed monthly Oceanic Nino Index (ONI) data (data here), with 2a starting in January 1979 and 2b with the data starting in January 1970. With the 1979 start (Figure 2a), there is a noticeable trend from positive values to negative, but with the 1970 start (Figure 2b) the trend line flattens greatly.

Figure 2a

Figure 2b


Figures 3a and 3b present the unsmoothed monthly NOAA NINO3.4 Index data (data here), 3a with the data starting in January 1979 and 3b with the data starting in January 1970. With the 1979 start (Figure 3a), there is a very minor trend from positive values to negative, but with the 1970 start (Figure 3b) the trend changes sign to a very minor trend from negative to positive.

Figure 3a

Figure 3b


A reminder: The noisy, off-equatorial, sea-level-pressure-based Southern Oscillation Index (SOI) data shows El Niño events as downward spikes and La Niña events as upward ones…the opposite of the sea surface temperature-based ENSO indices. Figures 4a and 4b present the unsmoothed monthly Southern Oscillation Index (SOI) data (data here), 4a with the data starting in January 1979 and 4b with the data starting in January 1970. With the 1979 start (Figure 4a), there is a noticeable trend from negative (El Niño) values to positive (La Niña) ones, but with the 1970 start (Figure 4b) the trend flattens very noticeably.

Figure 4a

Figure 4b


Figure 5 presents the unsmoothed monthly Multivariate ENSO Index (MEI) starting in January 1979 (data here). A couple of things stand out: Note how the strong El Niño of 2015/16 has a lesser peak value than strong 1982/83 and 1997/98 El Niños, while with the sea-surface-temperature-only-based ENSO indices (ONI and NINO3.4 Index) show the 2015/16 El Niño peaks at a higher value than the other two. Note also how the La Niña events toward the end of the MEI data have much greater negative values than the ONI and NINO3.4 data, while toward the beginning, the La Niñas have lesser negative values.

Figure 5

The MEI data appears very skewed toward a negative trend compared to the sea-surface-temperature-only-based ENSO indices; therefore, the next time some alarmist says that strong El Niños are growing stronger due to global warming show them a graph of the MEI data.


In closing, here’s a very brief introduction to El Niño events from one of my recent short stories. It was also included in a 2019 post here at WUWT:

Most news stories about El Niños call them unusual warming events in the eastern tropical Pacific Ocean, off the west coast of South America. They’re the cause of the huge upward spikes we see in the global surface temperature graphs.

They are much more than just warming events, and, further, regardless of what the numbskull science reporters say, there’s nothing unusual about them.” … “Magnificent would be a better word. Here are the facts. El Niño events occur every two to seven years. El Niños are the most-amazing, and the most powerful, weather events ever devised by Mother Nature. How powerful? El Niños are often kick-started by series of tropical storms in the western tropical Pacific.

Further from that post:

El Niño and La Niña events act together as a chaotic, naturally occurring, sunlight-fueled, recharge-discharge oscillator, with El Niño events acting as the discharge phase and La Niña events acting as the recharge phase...

I hope you enjoyed this post. Have fun.


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 El Nino-La Nina Processes, Uncategorized. Bookmark the permalink.

22 Responses to Response to Willis Eschenbach’s WUWT Post “How The El Nino Is Changing” 

  1. Bob Tisdale says:

    Yup, I came out of retirement to comment on Willis Eschenbach’s recent ENSO post at WUWT. I tried to remain as objective as possible.


  2. Bob Tisdale says:

    Thanks for the reblog, HiFast.


  3. Bob Tisdale says:

    UPDATE: I corrected two typos in the post.


  4. Janice Moore says:

    Very nice, Bob. Highly informative and easily readable by a non-scientist.

    SO GLAD to see your fine, data-driven, “just the facts,” analysis once again. We need more articles like yours at WUWT…

    Re: your being objective, you succeeded.

    FYI: I, too, never read W. E.’s posts anymore. He lets his emotions distort his arguments to the point that they are either inaccurate or become very unpleasant-to-read personal attacks. Also, he often either cannot or will not carefully consider what others try to tell him. Finally, he regularly asserts what others have already discovered, sometimes decades before, as his own, new, idea. Finally, even in his better articles, his megalomania colors them to the extent that they cause one to wince more than to nod and smile. And, perhaps, since 2014 (or so, can’t remember when I last read his writing), he has reformed and is a joy to read, now. I wouldn’t know.

  5. Bob Tisdale says:

    UPDATE 2: At the suggestion of a friend, I’ve also made a few other changes to the text, including rewriting the closing.


  6. Janice Moore says:

    Hi, Bob,

    My comment went to moderation and never re-appeared. Just letting you know. Given, you have commented since I submitted that, I’m guessing you didn’t find it suitable for publishing, not sure why….
    Anyway, in case it went to some kind of “spam bin,” wanted you to know I tried to comment and compliment you on a fine article.

    Thank you (again) for your excellent analysis.


  7. Janice Moore says:

    I just re-read the article. I think your friend was mistaken in his or her suggestions. Your refreshing candor about that egomaniac was A JOY to read. All we ever see are his “fan boys.” Ugh. Disappointed, but, still in admiration of your fine analysis.


  8. Bob Tisdale says:

    Hi, Janice. I just approved your string of comments that were in moderation. Has your missing comment appeared? If so, sorry if I missed it earlier. If not, I have no idea where it is.

    Also, I very much appreciate your comments on the content of the post.

    I was told it would appear at WUWT soon. Hopefully, that means tomorrow sometime. Considering the backlog there, maybe Saturday or Sunday…I hope.


  9. Janice Moore says:

    Lol. Good for you, Bob. You published every last one of my comments. Good!

    Hope your article appears on WUWT soon.

  10. Bob Tisdale says:

    UPDATE 3: Just corrected “sea-level-based Southern Oscillation Index” to “sea-level-pressure-based Southern Oscillation Index”.


  11. Jamal Munshi says:



    I am not blogging regularly either

  12. Bob Tisdale says:

    Jamal, thank you.


  13. Bob Tisdale says:

    Willis Eschenbach stated in his post, “And all four indices, in varying amounts, show this exact outcome—in response to the slow gradual warming since 1980, we have more La Nina conditions cooling the planet.”

    “…cooling the planet.”????

    That’s a very curious statement, because the HADISST-based sea surface temperature data for the Tropical Pacific have warmed, not cooled, since 1979, according to the slope of the trendline …

    …and not even the HADISST-based sea surface temperature data for the Equatorial Pacific show cooling during that time period, according to the slope of the trendline:

    And, as expected, it’s worse if we plot NOAA’s “pause buster” ERSST.v5 sea surface temperature data, with the tropical Pacific data here…

    …and the equatorial Pacific data here:

    “…cooling the planet.”????


  14. Bob Tisdale says:

    For those interested in how precipitation responds to El Niño and La Niña events where those events are taking place, I’ve prepared 4 comparison graphs using the NOAA Nino3.4 index, as a reference for the time and strength of El Niño and La Niña events, and NOAA’s CAMS-OPI precipitation data, the latter of which is available through the KNMI Climate Explorer in anomaly form. I’m presenting precipitation data for the NINO3.4 region (5S-5N, 170W-120W) in 2 graphs and the Eastern Tropical Pacific (20S-20N, 180-80W) in the other two. The CAMS-OPI precipitation data at the KNMI Climate Explorer begins in January 1983, near or at the peak of the very strong 1982/83 El Niño and ends in August 2020, near the beginning of the 2020/21 La Niña. The CAMS-OPI data are based on rain-gauge and satellite data. It is presented in mm/day. As noted on the first and second graphs, I’ve scaled the CAMS-OPI data for the NINO3.4 region by a factor of 0.21 to bring its variations more into line with the NINO3.4 data. In other words, I multiplied the CAMS-OPI values by 0.21. See Figure A below.

    Figure A – NINO3.4 SSTa versus NINO3.4 Precipitation Anomalies

    The first thing that stood out to me was that NINO3.4 region precipitation anomalies increased during El Niño events as expected, but did not decrease proportionally during La Niña events. The second thing to catch my eye was that the precipitation anomalies response was not consistent during strong El Niño events. In fact, there was comparatively little response of precipitation during the 2015/16 El Niño.
    It’s also very obvious that there is a seasonal component to the precipitation anomalies. To reduce those, I’ve smoothed both datasets with 13-month running-average filters centered on month 7 in the graph below in Figure B.

    Figure B – Smoothed NINO3.4 SSTa versus NINO3.4 Precipitation Anomalies

    I thought it might be possible that the curious responses of precipitation to ENSO events were local to the relatively small NINO3.4 region (5S-5N, 170W-120W), so I increased the area to the Eastern Tropical Pacific (20S-20N, 180-80W) for the next 2 graphs. Note that I did not have to scale the precipitation data in this instance. See the Figure C below.

    Figure C – NINO3.4 SSTa versus Eastern Tropical Pacific Precipitation Anomalies

    As we can see in the unsmoothed version (above in Figure C) and the smoothed version (below in Figure D) versions of the comparison graphs, the minimal precipitation response to La Niña events and the inconsistent response to strong El Niño events continue to exist even across the entire Eastern Tropical Pacific.

    Figure D – Smoothed NINO3.4 SSTa versus Eastern Tropical Pacific Precipitation Anomalies

    That’s it for this comment.

  15. Bob Tisdale says:

    Note: The version of the Multivariate ENSO Index (MEI) presented in the post above is the current version, Version 2. The original version, which NOAA identifies as mei.old in the http address, begins in 1950. Its data is also available online:

    NOAA discusses the MEI.OLD here:

    The data online for MEI.OLD ends in November 2018. The graph below illustrates the version beginning in January 1970. There appears to be a discontinuity, in the form of an upward shift, in 1976.

    That’s it for this comment.


  16. Janice Moore says:

    Dear Bob,

    What’s the deal with WUWT?? They still haven’t published your EXCELLENT response. Did I miss it?

    Cheering for you! Go, Bob, our hero for data-driven, bona fide, science!


  17. Bob Tisdale says:

    Thank you very much for your comment, Janice. It’s being added to the queue as we speak.

    Thanks again,

  18. Pingback: Response to Willis Eschenbach’s WUWT Post “How The El Nino Is Changing” - Climate-

  19. Pingback: Response to Willis Eschenbach’s WUWT Post “How The El Nino Is Changing” - The Crude Truth

  20. Ashok Patel says:

    I had been following you at WUWT and have read various updates on ENSO for many years. I learnt how to prepare a Boiler Plate template for ENSO, which I have been using to report the same on my website at .
    My last post about the current Double Dip La Nina event was updated on 5th October 2022. The link is .
    Any suggestions Bob?

  21. Bob Tisdale says:

    Hi, Ashok Patel. Thank you for following my ENSO updates at WUWT.

    I read your comment on the thread of the cross post at WUWT and visited your website then. Sorry I didn’t get a chance to reply to you at that time. I just reread your post. It looks good and I’ll check back when you update for the triple-dip La Nina after we cross into the new year.


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