El Niño-Southern Oscillation Myth 2: A New Myth – ENSO Balances Out to Zero over the Long Term

Guest post by Bob Tisdale

This is the second part in a series of posts about El Niño-Southern Oscillation (ENSO). They address many of the myths and misunderstandings about the tropical Pacific processes that herald themselves during El Niño and La Niña events. In them, I’m simply reproducing chapters from my recently published ebook Who Turned on the Heat?

For almost 4 years, my presentations about the long-term effects of El Niño and La Niña events indicate the global oceans over the past 30+ years have warmed naturally. The long-term impacts of El Niño and La Niña are blatantly obvious. Proponents of anthropogenic global warming apparently have difficulty comprehending that so they use misinformation to try to contradict what’s plainly visible. Many of the myths they’ve created are failed attempts to neutralize strong El Niño and La Niña events—to redirect the observable causes of the warming over the past 3 decades from natural factors to manmade greenhouse gases.

The following discussion is from Chapter 7.3 A New Myth – ENSO Balances Out to Zero over the Long Term.

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A new myth about ENSO recently appeared in posts at the website SkepticalScience. This year one author there has been writing something to the effect of, El Niño and La Niña events balance out to zero over the long term. That’s nonsense, plain and simple nonsense. There are a number of ways to show the errors with this myth. The best way is to create a running total of NINO3.4 sea surface temperature anomalies.

Wikipedia provides an easy-to-understand explanation of a Running Total:

A running total is the summation of a sequence of numbers which is updated each time a new number is added to the sequence, simply by adding the value of the new number to the running total. Another term for it is partial sum.

The purposes of a running total are twofold. First, it allows the total to be stated at any point in time without having to sum the entire sequence each time. Second, it can save having to record the sequence itself, if the particular numbers are not individually important.

If, over the long term, El Niño and La Niña events balanced out to zero, then a running total of NINO3.4 sea surface temperature anomalies would equal zero. Does it? Refer to Figure 7-10.

El Niño and La Niña events obviously have NOT balanced out to zero over the past 30+ years. That curve of the running total of NINO3.4 data looks surprisingly similar to the global sea surface temperature anomaly curve. It’s really difficult to miss the very obvious increase.

I’ve actually had someone reply in a blog comment that 30 years was not long enough. I then provided a running total of NINO3.4 sea surface temperature anomalies starting in 1900. That early start year is pushing the boundaries when it comes to equatorial sea surface temperature data. The Panama Canal opened in 1914, and before then, equatorial Pacific sea surface temperature data becomes increasingly sparse.

The base years for anomalies would also impact the running total, especially one that long, so we need to pick some. Trenberth (1997) The Definition of El Niño stated that 1950 to 1979 was the best base period for NINO3.4 sea surface temperature anomalies. Trenberth writes:

Figure 1 shows the five month running mean SST time series for the Niño 3 and 3.4 regions relative to a base period climatology of 1950-1979 given in Table 1. The base period can make a difference. This standard 30 year base period is chosen as it is representative of the record this century, whereas the period after 1979 has been biased warm and dominated by El Niño events (Trenberth and Hoar 1996a). Mean temperatures are higher in the Niño 3.4 region than in Niño 3 and its proximity to the Pacific warm pool and main centers of convection is the reason for the physical importance of Niño 3.4.

We’ll use 1950 to 1979 as the base period for anomalies for our NINO3.4 sea surface temperature anomalies.

Figure 7-11 is the running total of HADISST NINO3.4 sea surface temperature anomalies, starting in January 1900 and ending in May 2012. It does not return to zero. However, it really looks like the global temperature anomaly curve.

The similarity between the curve of the running total of HADISST-based NINO3.4 sea surface temperature anomalies and a global temperature anomaly curve is remarkable. Unfortunately, it only works with HADISST-based NINO3.4 data. A running total of NINO3.4 data based on the ERSST.v3b or Kaplan datasets bears no similarities to the global temperature curve. Also, it only works with the base years of 1950-1979. That is, if you were to shift the base years so that they were weighted more toward El Niño events, like the period of 1971 to 2000, you’d wind up with a long-term running-mean curve that looks completely different. That makes the curve illustrated in Figure 7-11 a curiosity. Nothing more—just a curiosity, because I can’t justify the use of the base years of 1950-1979. It should definitely make you think, though.

That running total was one of the things that sparked my interest in ENSO. I discovered that curious running-total effect in April 2008, and presented it in a post titled Is There A Cumulative ENSO Climate Forcing? (ENSO isn’t a forcing, but that’s neither here nor there.) If you were to include the effects of volcanic aerosols and solar variability, the fit becomes even better. I presented that in a post titled Reproducing Global Temperature Anomalies With Natural Variables.

Regardless, ENSO has been skewed toward El Niño in recent decades. It has been skewed toward La Niña as well—the period from the 1940s to the mid-1970s for example. This is well known. We’ve shown the “skewness” in the preceding chapter using period average sea surface temperatures for the NINO3.4 region.

The myth that “El Niño and La Niña events balance out to zero over the long term” is simply another very obvious attempt to neutralize El Niño and La Niña. It’s a comical attempt that failed.

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The illustration from a previous chapter I was referring to above was Figure 7-7 from Chapter 7.1 Myth – ENSO Has No Trend and Cannot Contribute to Long-Term Warming.

I’ll present that chapter next.  (Hmm.  Just noticed a typo.  In the book, the illustration is identifed as Figure 5-7.  I’ve corrected it here.)

SOURCES

The sea surface temperature data for Figure 7-10 was downloaded from the NOAA NOMADS website. NOAA uses 1971-2000 as base years. The dataset used in the other graphs is HADISST. It’s available through the KNMI Climate Explorer. There I’ve used the base years of 1950-1979 per the discussion above.

THE REST OF THIS SERIES

The remainder of this series of posts will be taken from the following myths and failed arguments. They’re from Section 7 of my book Who Turned on the Heat? I may select them out of the order they’ve been presented here, and I’ll try to remember to include links to the other posts in these lists as the new posts are published.

ALREADY PUBLISHED

1. El Niño-Southern Oscillation Myth 1: El Niño and La Niña Events are Cyclical. Refer also to the cross post at WattsUpWithThat for comments.

UPCOMING

Myth – ENSO Has No Trend and Cannot Contribute to Long-Term Warming

Myth – The Effects of La Niña Events on Global Surface Temperatures Oppose those of El Niño Events

Failed Argument – El Niño Events Don’t Create Heat

Myth – El Niño Events Dominated the Recent Warming Period Because of Greenhouse Gases

Myth – ENSO Only Adds Noise to the Instrument Temperature Record and We Can Determine its Effects through Linear Regression Analysis, Then Remove Those Effects, Leaving the Anthropogenic Global Warming Signal

Myth – The Warm Water Available for El Niño Events Can Only be Explained by Anthropogenic Greenhouse Gas Forcing

Myth – The Frequency and Strength of El Niño and La Niña Events are Dictated by the Pacific Decadal Oscillation

And I’ll include a few of the failed arguments that have been presented in defense of anthropogenic warming of the global oceans.

Failed Argument – The East Indian-West Pacific and East Pacific Sea Surface Temperature Datasets are Inversely Related. That Is, There’s a Seesaw Effect. One Warms, the Other Cools. They Counteract One Another.

INTERESTED IN LEARNING MORE ABOUT EL NIÑO AND LA NIÑA AND THEIR LONG-TERM EFFECTS ON GLOBAL SEA SURFACE TEMPERATURES?

Why should you be interested? Sea surface temperature records indicate El Niño and La Niña events are responsible for the warming of global sea surface temperature anomalies over the past 30 years, not manmade greenhouse gases. I’ve searched sea surface temperature records for more than 4 years, and I can find no evidence of an anthropogenic greenhouse gas signal. That is, the warming of the global oceans has been caused by Mother Nature, not anthropogenic greenhouse gases.

I’ve recently published my e-book (pdf) about the phenomena called El Niño and La Niña. It’s titled Who Turned on the Heat? with the subtitle The Unsuspected Global Warming Culprit, El Niño Southern Oscillation. It is intended for persons (with or without technical backgrounds) interested in learning about El Niño and La Niña events and in understanding the natural causes of the warming of our global oceans for the past 30 years. Because land surface air temperatures simply exaggerate the natural warming of the global oceans over annual and multidecadal time periods, the vast majority of the warming taking place on land is natural as well. The book is the product of years of research of the satellite-era sea surface temperature data that’s available to the public via the internet. It presents how the data accounts for its warming—and there are no indications the warming was caused by manmade greenhouse gases. None at all.

Who Turned on the Heat?was introduced in the blog post Everything You Every Wanted to Know about El Niño and La Niña… …Well Just about Everything. The Updated Free Preview includes the Table of Contents; the Introduction; the beginning of Section 1, with the cartoon-like illustrations; the discussion About the Cover; and the Closing. The book was updated recently to correct a few typos.

Please buy a copy. (Credit/Debit Card through PayPal. You do NOT need to open a PayPal account. Simply scroll down past where they ask you to open one.). It’s only US$8.00.

VIDEOS

For those who’d like a more detailed preview of Who Turned on the Heat? see Part 1 and Part 2 of the video series The Natural Warming of the Global Oceans. Part 1 appeared in the 24-hour WattsUpWithThat TV (WUWT-TV) special in November 2012. You may also be interested in the video Dear President Obama: A Video Memo about Climate Change.