The monthly sea surface temperature anomaly updates for the past few years have included, among others, a breakdown of the global oceans into two subsets:
- East Pacific Ocean (Recent graph here)
- Atlantic-Indian-West Pacific Oceans; a.k.a. the Rest of the World (Recent graph here)
I had broken down the global data into those two subsets because:
- the East Pacific data show very little warming for that large portion (33%) of the global oceans, and
- the Atlantic-Indian-West Pacific data (the other 67%) show the surfaces of those oceans (combined) warmed in very clear upward steps in response to the El Niño events of 1986/87/88 and 1997/98 and 2009/10.
With the upcoming El Niño, for the future updates, I’m eliminating the data for the Atlantic-Indian-West Pacific Oceans and replacing it with the sea surface temperature data for the South Atlantic-Indian-West Pacific Oceans; in other words, I’ve removed the North Atlantic data from the “Rest of the World” data. There a couple of reasons for this.
If we look at a map that presents the warming and cooling rates of the surfaces of the global oceans from 1982 to 2013 (the term of the Reynolds OI.v2 satellite-enhanced SST data), Figure 1, we can see that:
- the surfaces of the North Atlantic (including the Mediterranean and Black Seas and its portion of the Arctic Ocean) have warmed the most over that time. That, of course, is a response to the additional warming associated the Atlantic Multidecadal Oscillation (AMO). See the NOAA AMO FAQ webpage here and my blog posts here and here for more info on the Atlantic Multidecadal Oscillation.
- the surface of the East Pacific Ocean (from pole to pole) shows cooling in some portions and warming in others, and as a result, the sea surface temperatures of the East Pacific show little increase.
- the surfaces of the South Atlantic, Indian and West Pacific Oceans show they have warmed, but they have warmed at a lesser rate than the North Atlantic, and we know, based on past discussions, that the sea surface temperatures there warm in very obvious upward steps in responses to strong El Niño events.
By including the North Atlantic in the region where we’re looking for ENSO-related upward shifts, the results are biased by the Atlantic Multidecadal Oscillation.
COMPARISON OF NORTH ATLANTIC, EAST PACIFIC AND SOUTH ATLANTIC-INDIAN-WEST PACIFIC DATA
Figure 2 compares the satellite-era sea surface temperature data for the North Atlantic Plus (0-90N, 80W-40E), East Pacific (90S-90N, 180-80W), and the South Atlantic-Indian-West Pacific, the last of which is a weighted average of the data for the coordinates of 0-90N, 40E-180 at 27.9% and for the coordinates of 90S-0, 80W-180 at 72.1%.
By far, the North Atlantic has the highest warming rate. The trend of the North Atlantic data is more than double the trend of the data for the South Atlantic-Indian-West Pacific Oceans. Based on the trends, it is sometimes wrongly said that the North Atlantic contributed the most to global warming. In reality, the additional warming of the North Atlantic, as a result of the Atlantic Multidecadal Oscillation, enhanced the warming we’ve experienced since the mid-1970s, but, because the South Atlantic-Indian-West Pacific Oceans cover a much greater area than the North Atlantic, the warming of the surfaces of the South Atlantic-Indian-West Pacific Oceans actually contributed the most the global warming. We can see this by area weighting the data. For Figure 3, it’s assumed that the North Atlantic Plus data cover 14.5% of the surface of the global oceans, that the East Pacific data cover 33% and that the South Atlantic-Indian-West Pacific Oceans cover 52.5%.
While each of the three subsets are important for their own reasons, it is the South Atlantic-Indian-West Pacific region that contributed the most to global warming. And the climate-science community has never bothered to explain why it warms in El Niño-related steps.
NORTH ATLANTIC PLUS REGION VERSUS THE “NORMAL” NORTH ATLANTIC
The North Atlantic sea surface temperature anomalies are always included in the monthly updates. The most recent illustration of the North Atlantic data is here. The coordinates used in the update are 0-70N, 80W-0, which are the coordinates used by NOAA for their AMO data. But I’ve been using the coordinates of 0-90N, 80W-40E in this post for the “North Atlantic Plus” region, adding the Mediterranean and Black Seas and a portion of the Arctic Ocean to it. I know I’ve shown this in the past, but in case you weren’t around back then, the two datasets are almost identical. See Figure 4. They have, in effect, the same basic warming rate of 0.22 deg C/decade, and the correlation coefficient for the two datasets is 0.98, where 1.0 is perfect.
So I’m not going to change the coordinates for the North Atlantic data in the updates. I’ll leave them the same as those used by NOAA for their AMO data.
SOUTH ATLANTIC-INDIAN-WEST PACIFIC DATA PRESENTATION
I’ll present the sea surface temperature data for the South Atlantic-Indian-West Pacific Oceans with the same format used for its predecessor. See Figure 5.
The periods used for the significant El Niño events of 1982/83, 1986/87/88, 1997/98, and 2009/10 and the average sea surface temperature anomalies between them are determined as follows. Using the original NOAA Oceanic Nino Index (ONI) for the official months of those El Niño events, I shifted (lagged) those El Niño periods by six months to accommodate the lag between NINO3.4 SST anomalies and the response of the sea surface temperature anomalies for the South Atlantic-Indian-West Pacific Oceans. The data that corresponds to those significant El Niño events is excluded. Then the sea surface temperature data between those El Niño-related gaps are averaged.
It’s blatantly obvious that the sea surface temperature anomalies of the South Atlantic-Indian-West Pacific Oceans warmed in upward steps, but the data shows the oceans cooling slightly between the 1986/87/88 and 1997/98 El Niños and between the 1997/98 and 2009/10 El Ninos. That cooling was not evident if we included the North Atlantic data.
We’re isolating the South Atlantic-Indian-West Pacific data to see if history repeats itself with another upward step in response to the 2014/15 El Niño…assuming it continues to form.
THE AREA-WEIGHTED COMPARISON HELPS TO SHOW WHY AND WHEN SEA SURFACE TEMPERATURES HAVE WARMED
Figure 3 above showed why the South Atlantic-Indian-West Pacific data acquired their long-term trend, but the North Atlantic data obscured it. So let’s delete the North Atlantic data. See Figure 6. If we focus on the upward spike associated with the 1997/98 El Niño, we can see that the area-weighted responses to the evolution of the El Niño are similar in magnitude, with the South Atlantic-Indian-West Pacific data trailing the East Pacific data. Then during the decay of the El Niño and the transition to the La Niña, we can see that the East Pacific responds fully, but on the other hand, the South Atlantic-Indian-West Pacific data do not.
For more than 5 years, we’ve discussed the reasons why the South Atlantic-Indian-West Pacific data do not cool fully during the transition from the strong El Niños to La Niñas that trail them. I discussed this once again in the post Answer to the Question Posed at Climate Etc.: By What Mechanism Does an El Niño Contribute to Global Warming? There I wrote:
An El Niño discharges heat stored in the form of warm water from below the surface of the West Pacific Warm Pool, or as Trenberth et al. (2002) noted “the heat is stored in the western Pacific tropics.” That discharged warm water rises to the surface through upwelling and releases heat to the atmosphere during the El Niño (primarily through evaporation), and then all of the remaining warm water that was discharged by the El Niño is subsequently redistributed around the global oceans at the conclusion of the El Niño, some on the surface and some below the surface of the oceans. Let’s rephrase that because it’s important. The discharge phase is the release of “the heat [that] is stored in the western Pacific tropics”, which is taking subsurface warm water from the West Pacific Warm Pool and initially relocating it into the eastern tropical Pacific where it is upwelled to the surface and then subsequently redistributed at the conclusion of the El Niño. One of the byproducts of that discharge of warm water from “western Pacific tropics” is the release of heat to the atmosphere, and that’s what many persons focus on, but it’s only a portion of the discharge phase.
Which brings us to the Trenberth “big jumps” in response to the strong El Niño events of 1986/87/88, 1997/98 and 2009/10. (I initially discussed Trenberth’s “big jumps” article here.) Those “big jumps” are plainly evident in the sea surface temperature anomalies of the South Atlantic, Indian and West Pacific Ocean. See the graph here. Two things are stand out in that graph: (1) the warming of the sea surface temperatures for the South Atlantic-Indian-West Pacific occurs during the El Niño events and (2) the sea surface temperatures there do not respond proportionally during the trailing La Niñas. Those upward shifts are the long-term responses to the discharge phases of ENSO that occurs during strong El Niños. As part of the discharge phase of ENSO, the El Niño takes warm water from below the surface of the western tropical Pacific and places it on the surface (warm water that was created by the increased sunlight during the prior recharging La Niña). The discharged warm water floods into the East Pacific, where it temporarily raises sea surface temperatures during the El Niño, but causes little long-term trend there. And at the end of the El Niño, the warm water is redistributed by the renewed trade winds, ocean currents and the downwelling Rossby wave into the West Pacific, Indian Ocean and eventually the South Atlantic.
I’ll include a link to this post in that section of the monthly updates staring in May 2014.
INTERESTED IN LEARNING MORE ABOUT HOW AND WHY THE GLOBAL OCEANS INDICATE THEY’VE WARMED NATURALLY?
Why should you be interested? The hypothesis of manmade global warming depends on manmade greenhouse gases being the cause of the recent warming. But the sea surface temperature record indicates El Niño and La Niña events are responsible for the warming of global sea surface temperature anomalies over the past 32 years, not manmade greenhouse gases. Scroll back up to the discussion of the East Pacific versus the Rest of the World. 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 published an 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 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.
Please buy a copy. (Paypal or Credit/Debit Card). You do not need to have a PayPal account. Simply scroll down to the “Don’t Have a PayPal Account” purchase option. It’s now sale priced at US$5.00.
The Sea Surface Temperature anomaly data used in this post is available through the NOAA NOMADS website: