Mid-May 2013 Sea Surface Temperature Anomaly Update

The sea surface temperature anomalies of the NINO3.4 region in the equatorial Pacific (5S-5N, 170W-120W) are a commonly used metric for the frequency, strength and duration of El Niño and La Niña events. For the week centered on May 15, 2013, they’ve dropped well below zero but have not reached the threshold of a La Niña (-0.5 deg C). They’re at about -0.28 deg C.

Weekly NINO3.4

Weekly NINO3.4

Global sea surface temperatures are at +0.195 deg C for the week centered on May 15th. As noted in earlier updates, a global sea surface temperature anomaly of +0.2 deg C appears to have become the “new normal”. Other than the rises and falls in response to El Niño and La Niña events, it doesn’t look as though they’ve wandered very far from that value over the past 11-plus years.

Weekly Global

Weekly Global


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’ve searched ocean heat content records for more than 3 years, and I can find no evidence of an anthropogenic greenhouse gas signal. That is, the data indicates the warming of the global oceans has been caused by Mother Nature, not anthropogenic greenhouse gases.

For a further discussion, see the essay (pdf) titled The Manmade Global Warming Challenge. (It’s 42MB, but it’s free and worth the download time.)

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 Ever 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 to the “Don’t Have a PayPal Account” purchase option. It’s only US$8.00.


For those who’d like a more detailed preview of Who Turned on the Heat?, see Parts 1 and 2 of the video series The Natural Warming of the Global Oceans.


The Sea Surface Temperature anomaly data used in this post is available through the NOAA NOMADS website:




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.
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3 Responses to Mid-May 2013 Sea Surface Temperature Anomaly Update

  1. Green Sand says:

    Hi Bob, many thanks for the update. I note “not reached the threshold of a La Niña (-0.5 deg C).”

    Do you know if the BOM have widened their La Nina/El Nino thresholds? Or has there always been a difference? Would appreciate your comments. TIA

    The following has just been posted by ukphonta at BH:-

    “Climate Model Summary

    ‘The following graph shows the average forecast value of NINO3.4 for each international model surveyed for the selected calendar month. If the bars on the graph are approaching or exceeding the blue dashed line, there is an increased risk of La Niña. Similarly, if the bars on the graph are approaching or exceeding the red dashed line, there is an increased chance of El Niño.’

    Lines set at +/-0.8C

    ‘NINO3.4 and other indices

    The National Climate Centre (NCC) uses the “NINO3.4 index” to classify ENSO conditions (see “Note:” below). The NINO3.4 index is defined as the average of SST anomalies over the region 5°N – 5°S and 170° – 120°W. NCC classifies the NINO3.4 temperature anomaly as “warm” if it exceeds 0.8°C, which is about one standard deviation above average. Similarly, anomaly predictions below –0.8°C are tabled as “cool”, with those in between classed “neutral”. There are also other “NINO” indices that refer to SST anomalies over different areas of the Pacific Ocean. The regions covered by the NINO indices are shown in this map of the tropical Pacific Ocean. ‘

  2. Bob Tisdale says:

    Green Sand: The differences between the BOM and NOAA classifications of El Nino and La Nina conditions have existed for as long as I’ve known.

  3. Green Sand says:

    Thanks Bob!

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