Does The Sea Surface Temperature Record Support The Hypothesis Of Anthropogenic Global Warming?
Guest post by Bob Tisdale
This post is an expansion on my earlier post Sea Surface Temperature Anomalies – East Pacific Versus The Rest Of The World. In that post, I broke the satellite-era Sea Surface Temperature (SST) anomaly data for the global oceans into two subsets. The volcano-adjusted East Pacific SST anomaly data (90S-90N, 180-80W) shows no rise for the past 30 years and the SST anomalies for the Rest-Of-The-World (90S-90N, 80W-180) rose in two easily discernable steps. I used period average SST anomalies to highlight the steps.
This post is also similar in content to the post How Can Things So Obvious Be Overlooked By The Climate Science Community? But in this one, I provided a better way to divide the decade-plus periods that run from the end of the 1986/87/88 El Niño to the beginning of the 1997/98 El Niño and from end of the 1997/98 El Nino to the beginning of the 2009/10 El Niño. This allows for a more consistent way to illustrate the actual Rest-Of-The-World SST anomaly trends between those significant ENSO events.
THE ONE-WORD ANSWER TO THE TITLE QUESTION IS NO.
The satellite-era Sea Surface Temperature record indicates they rose only in response to significant El Niño events. In other words, the Sea Surface Temperature data contradicts the IPCC hypothesis that most of the rise is caused by an increase in Anthropogenic Greenhouse Gases.
The fact that the satellite-era SST anomalies do not support AGW is very easy to illustrate with two graphs, Figure 1. They show the satellite-based sea surface temperature (SST) anomalies for two subsets of the global oceans, using Reynolds OI.v2 SST data that runs from November 1981 (the start of that dataset) to the current month of May 2011. The graph on the left illustrates the volcano-adjusted Sea Surface Temperature for the eastern Pacific from pole to pole (90S-90N, 180-80W). That area represents about 33% of the global ocean surface area. There are major variations from year to year caused by El Niño and La Niña events, but the linear trend is basically flat at +0.003 deg C per decade. In other words, there has been no rise in the volcano-adjusted Sea Surface Temperatures for that portion of the global oceans in almost 30 years. The graph on the right illustrates the volcano-adjusted SST anomalies for the rest of the world from pole to pole (90S-90N, 80E-180). The SST anomalies for this portion of the globe show two distinct upward steps with periods of relatively little (if any) rise between those steps. The upward steps are highlighted by the average SST anomalies for the periods between the upward shifts caused by El Niño-Southern Oscillation events. There is an upward step in 1987 that occurs in response to the 1986/87/88 El Niño, and there is an upward step in 1997, which is a response to the 1997/98 El Niño. Note how the Rest-Of-The-World SST data appears to be in the process of another upward step in response to the 2009/10 El Niño.
Figure 1
Figures 2 and 3 are full-sized versions of the volcano-adjusted East Pacific and Rest-Of-The-World SST anomaly graphs. These datasets were first discussed in my post Sea Surface Temperature Anomalies – East Pacific Versus The Rest Of The World, and they have appeared in my monthly SST anomaly updates since then. Two notes: The Sea Surface Temperature dataset used in this post is NOAA Optimum Interpolation, version 2 SST, also known as Reynolds OI.v2. And as noted during the discussion of Figure 1, both subsets have been adjusted for the effects of the explosive volcanic eruptions of El Chichon in 1982 and Mount Pinatubo in 1991. I performed a linear regression analysis on global SST anomalies to account for the impacts of the volcanic aerosols. This was discussed in the post linked above.
Figure 2
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Figure 3
THE REST-OF-THE-WORLD SST ANOMALY TRENDS BETWEEN THE SIGNIFICANT EL NIÑO EVENTS
Above I described the Rest-Of-The-World SST data as having two distinct upward steps with periods of relatively little (if any) rise between those steps. Actually, the linear trend for the period between the El Niño events of 1986/87/88 and 1997/98 is -0.01 deg C per decade and for the period between the El Niño events of 1997/98 and 2009/10 it’s +0.001 deg C per decade. Refer to Figure 4. In other words, the volcano-adjusted Rest-Of-The-World Sea Surface Temperature anomalies rose in response the significant El Niño events of 1986/87/88 and 1997/98, and then the sea surface temperatures did not rise over the decade (plus) periods that followed.
Figure 4
To establish the periods between the significant El Niño events, I used the NOAA Oceanic Nino Index(ONI) to determine the official months of the 1986/87/88, 1998/98, and 2009/10 El Niño events.. There is a 6-month lag between NINO3.4 SST anomalies and the response of the Rest-Of-The-World SST anomalies during the evolution phase of the 1997/98 El Niño. So I lagged the ONI data by six months and deleted all of the Rest-Of-The-World SST data that corresponded to the El Niño events of the 1986/87/88, 1998/98, and 2009/10 El Niño events. Then I performed the trend analyses on the data for the two periods that remained.
There will be those who will attempt to downplay the trend analyses shown in Figures 4 by stating that I’ve excluded the data after June 2009 to hide a rise in SST anomalies. In reality, I’ve excluded that recent data because the 2009/10 El Niño appears to be causing yet another upward step as shown in Figure 3.
CLOSING
Unless Anthropogenic Greenhouse Gases only impacted Sea Surface Temperature Anomalies during the 1986/87/88 and 1997/98 El Niño events, there is no evidence of Anthropogenic Global Warming in the satellite-era Sea Surface Temperature data. The volcano-adjusted East Pacific Ocean Sea Surface Temperature anomalies have not risen in 30 years. For the Rest Of The World, the volcano-adjusted Sea Surface Temperature anomalies rose only during the El Niño events of 1986/87/88 and 1997/98, but between the 1986/87/88 and 1997/98 El Niño events and between the 1997/98 and 2009/10 El Niño events, there was no rise in the volcano-adjusted Rest-Of-The-World Sea Surface Temperatures.
I have presented and described ENSO and the multiyear aftereffects of ENSO in numerous posts over the past years. Links to many of them are listed under the heading of FURTHER INFORMATION.
ENSO is a process that periodically discharges heat from the oceans and redistributes warm waters from the tropical Pacific. ENSO also recharges the tropical Pacific Ocean Heat through a periodic increase in Downward Shortwave Radiation. In that respect, ENSO events are fueled by a periodic increase in natural radiative forcing (solar energy) over the tropical Pacific. When El Niño events dominate a multidecadal era, indicating the tropical Pacific is releasing and distributing more ocean heat than “normal”, global surface temperatures rise. The opposite holds true during epochs when La Niña events dominate.
SOURCES
SST anomaly data is available through the NOAA NOMADS website:
http://nomad1.ncep.noaa.gov/cgi-bin/pdisp_sst.sh
or:
http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_sst.sh?lite
The GISS Global Stratospheric Aerosol Optical Thickness data is available here:
http://data.giss.nasa.gov/modelforce/strataer/tau_line.txt
FURTHER INFORMATION
My first detailed posts on the multiyear aftereffects of ENSO events are:
Can El Nino Events Explain All of the Global Warming Since 1976? – Part 1
And:
Can El Nino Events Explain All of the Global Warming Since 1976? – Part 2
And:
Supplement To “Can El Nino Events Explain All Of The Warming Since 1976?”
And:
Supplement 2 To “Can El Nino Events Explain All Of The Warming Since 1976?”
And for those who like visual aids, refer to the two videos included in:
La Niña Is Not The Opposite Of El Niño – The Videos.
The impacts of these El Nino events on the North Atlantic are discussed in:
There Are Also El Nino-Induced Step Changes In The North Atlantic
And:
Atlantic Meridional Overturning Circulation Data
I’ve also written a rebuttal post to Tamino’s AMO Post. I hope to have a new post on the North Atlantic posted sometime soon.
The posts related to the effects of ENSO on Ocean Heat Content are here:
ENSO Dominates NODC Ocean Heat Content (0-700 Meters) Data
And:
North Atlantic Ocean Heat Content (0-700 Meters) Is Governed By Natural Variables
Additional detailed technical discussions can be found here:
More Detail On The Multiyear Aftereffects Of ENSO – Part 1 – El Nino Events Warm The Oceans
And:
More Detail On The Multiyear Aftereffects Of ENSO – Part 2 – La Nina Events Recharge The Heat Released By El Nino Events AND…During Major Traditional ENSO Events, Warm Water Is Redistributed Via Ocean Currents.
And:
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Bob Tisdale says:
July 10, 2011 at 12:44 pm
So, the Satellite era does not give us any perspective on the La Nina dominated SST’s.
We’ll just have to wait some decades to see what that is like.
Some have put the ENSO change in 1998, some in 2007.
My take on when ENSO flipped is 2006/2007, so we are just now seeing the first effects.
The period of 1995 to present being globally flat temps is a result of the wane of the last ‘warm’ ENSO cycle, if the ENSO only flipped in 2006/7.
Your thought on this?
R. Gates says: “It seems a discussion of the relationship between total ocean heat content and SST’s would be useful as the longer-term warming signal from increased CO2 would favor being seen more readily in total OHC. “
Your comment sounds familiar, as if you’ve posted something similar on another thread of one of my guest posts here at WUWT. And in response to it, haven’t I provided links to posts in which I’ve illustrated and discussed that much of the rise in Global OHC since 1955 can be shown to result from ENSO:
http://bobtisdale.blogspot.com/2009/09/enso-dominates-nodc-ocean-heat-content.html
And AMO/AMOC:
http://bobtisdale.blogspot.com/2009/10/north-atlantic-ocean-heat-content-0-700.html
And shifts In Sea Level Pressure:
http://bobtisdale.blogspot.com/2009/12/north-pacific-ocean-heat-content-shift.html
Jack Greer says: “The least squared trend re: total solar irradiance over the past 30 years is mildly negative. The least squared trend re: global SST over the past 30 years is strongly positive.”
That’s nice to know, Jack, but how does your observation relate to my post?
Billy Liar says:
July 10, 2011 at 12:00 pm
“Have you noticed that your step increases coincide exactly with the last 3 solar minima. I believe there was a ‘climate shift’ in 1976 as well, another solar minimum.”
Speculation:
When each step up happens during a solar minimum, maybe because the trade winds relax during the solar minimum, allowing the warm pool to form a big El Niño, and discharging the Warm Pool, then what will the coming Grand minimum do? It will lead to a constant trickle-discharge of the Warm Pool so that it can never recharge completely and we will not see any El Niño’s during the Grand Minimum.
In my search for the natural causes related to the climate change, beside two already known in the N. Atlantic and N. Pacific (with promising correlations), there is one more, this time in the equatorial Pacific which correlates well to the integrated monthly Southern Oscillation Index, but only if delayed by ~12 years, possibly coincidence but unlikely.
http://www.vukcevic.talktalk.net/SOI.htm
Why there should be 12 year delay I have no idea; distance Darwin to Tahiti is about 8,500 km, so it would give velocity for the South Equatorial Current of 80m/hr, a bit on slow side but realistic for deeper level currents. Any ideas?
R. Gates says:
July 10, 2011 at 12:15 pm
“Assuming there aren’t other flaws in Bob’s analysis,…..”
========
What flaw did you find in “Bob’s analysis”?
Care to enlighten us ?
Crispin in Waterloo says:
July 10, 2011 at 1:35 pm
“and the gentle temperature rise out of the last ice age…”
_____
??? There’s been a “gentle temperature rise” out of the last ice age. Really? Please show your proof of this contention. Oh, perhaps you’re talking about the so-called “LIttle Ice Age” which was of course not an ice age at all? What are you talking about here??
R Gates says “[You asked if] the energy must be stored somewhere, and the answer may be the deeper oceans …”
I think there is a problem with that argument. As I understand the IPCC report, the global temperature predictions are based on the GHG-driven warming staying mainly in the upper layers of the oceans. If the GHG-driven warming is instead being spread through the deeper ocean, then the IPCC predictions of global temperature increases are far too high. (It takes a lot more energy to warm the deeper oceans than just the upper part).
Jim D says: “So you have proposed this ratchet effect whereby SSTs will increase ad infinitum, or do you suppose there is a cooling effect between these El Ninos that may be countered by AGW?”
I’ve never said the ratchet effect will increase SST anomalies ad infinitum. Regarding “a cooling effect between these El Ninos that may be countered by AGW”, the the multi-model mean of the IPCC 20C3m/SRES A1B Hindcasts/Projections show no skill at reproducing the observed rise, or lack thereof, in regional sea surface temperatures. I illustrated and discussed this in the following two posts:
http://bobtisdale.wordpress.com/2011/04/10/part-1-%e2%80%93-satellite-era-sea-surface-temperature-versus-ipcc-hindcastprojections/
And:
http://bobtisdale.wordpress.com/2011/04/19/492/
The hypothesis that anthropogenic greenhouse gases have any impact on sea surface temperatures is not supported by the satellite-era SST data or the IPCC’s 20C3m/SRES A1B Hindcasts/Projections.
James of the West says: “Isn’t it too early to tell if we have another step change upwards in SST?”
We’ll see what happens. That’s why I’ve included those East Pacific and Rest-Of-The-World SST datasets in my monthly updates. I’ll be posting the June data tomorrow, and I’ve deleted the 13-month smoothing in those two datasets.
FYI, I don’t believe Roy Spencer’s SST data is global. If memory serves me well, it runs from 60S-60N. By excluding the data poleward of those latitudes, he doesn’t have to deal with seasonal sea ice.
Ira Glickstein, PhD says: “Thus, over three ENSO cycles, the overall global mean SST has gone up by about 0.2ºC. Due to what?”
A one-sentence answer: The discharge and distribution of warm waters created by the ENSO process.
Maybe this is a silly question, but I guess the only silly questions are the ones you don’t ask.
Why adjusted the SST anomalies for volcanoes? I understand why you would for air temperature, but I would think that such a temporary difference would make such a big dent on the ocean. Wouldn’t the ocean temperature be harder to affect by changing the air temperature a half a degree or so?
In many of Bob’s posts on the SST of different ocean basins it can be seen that the entire South Pacific Ocean has been warming only gradually and the Southern ocean has not been warming at all.. To my eye it seems possible that the Southern Ocean SST has cooled slightly. So over the period from 1981 to present maybe one could say that there has been little or no warming in about 50% of the global ocean.
It would be interesting to see another posting from Bob showing essentially the same graphs as above but with the ocean surface areas reconfigured slightly to zero in on the areas that have warmed substantially and the areas that have not warmed significantly. Would this highlight the heat transfer process even more explicitly?
@- Bob Tisdale says:
July 10, 2011 at 3:46 pm
“Ira Glickstein, PhD says: “Thus, over three ENSO cycles, the overall global mean SST has gone up by about 0.2ºC. Due to what?”
A one-sentence answer: The discharge and distribution of warm waters created by the ENSO process.”
You cannot ‘create’ warm water from the ENSO process, you have to get energy from somewhere to warm water.
The ENSO process is not causal, it is a convenient description of warm/cold ocean currents, a way of parsing ocean processes. Its a reification of measurements, not a primary causal agent.
The essay mentions –
“ENSO also recharges the tropical Pacific Ocean Heat through a periodic increase in Downward Shortwave Radiation.”
However the last few decades have seen a DECREASE in downward shortwave radiation or TSI. If your hypothesis was right then there would be a step-change DOWN after every El Niño.
Kasuha says: “Sorry but I’m not buying that. If I cut just a few years from both sides on Figure 2 graph I can get a completely different slope and we can argue which of the two is cherry picking.”
There’s no cherry picking on my part with the start date. That’s when that data starts, And there’s no cherry picking about the end date either. But if you’re concerned that the start year is followed immediately by the 1982/83 El Nino, here’s the graph again starting in January 1984. I’ve also eliminated the smoothing—wouldn’t want you to complain about that, too:
http://i53.tinypic.com/2hp6mn4.jpg
So without the response of the 1982/83 El Niño, the trend rises to +0.013 deg C per decade. Do you know what the IPCC 20C3m/SRES A1B Hindcast/Projection linear trend is for that part of the global oceans? It’s ten times higher at 0.137 deg C per decade.
You asked, “And if it’s El Nino what’s adding to the temperature, where’s the force that’s keeping it constant in between?
The La Nina events that follow those El Nino events take the leftover warm water that was released from below the surface of the Pacific Warm Pool and redistributes it poleward in the western Pacific and into the East Indian Oceans. Here’s an animation of sea level residuals for the 1998/99/00/01 La Nina. The animation starts at the peak of the 1997/98 El Nino. Watch for a process that carries warm water west in the northern tropical Pacific, at about 10N. It’s called a Rossby wave. Follow it west and keep an eye on the western Pacific as that multiyear La Nina continues. The west Pacific and East Indian Oceans warrn during that La Nina, and very shortly thereafter there’s the 2002/03 El Nino, and it helps to maintain the elevated Sea Surface temperatures.
After watching that, do think La Nina events are the opposite of El Nino events?
Bob, you have probably realized by now from the general theme in the questions that you did not provide an energy balance. When clouds decrease and cause an anomaly warming, they also increase back to the previous cloud cover by the next El Nino causing an equal anomaly cooling, and the only way it can keep stepping up is for cloud cover never to quite recover between El Ninos. If this is what you are saying, you need to state it explicitly. Then the energy supply would be decreasing cloud cover, which is a testable hypothesis.
timetochooseagain says: “So what phenomenon results in multidecadal and longer cooling trends?”
Sorry,.I don’t have an answer for you. I present what exists in the data, Since we don’t have satellite-based SST data during a cooling epoch, I have no way to determine it. The AMO might impact it, but we’ll have to wait until North Atlantic SST anomalies start to decline.
Michael J says: “If I may, for a moment, play devil’s advocate, let me hypothesise this:
1. A constant(ish) positive forcing exists (e.g. CO2)”
There’s nothing in the SST or OHC records that indicate that CO2 has any noticeable impact.
DirkH says:
July 10, 2011 at 3:04 pm
I’ll be checking your hypothesis!
Bob,
When you say that ENSO is fuelled by periodic changes in solar radiative forcing, presumably you are referring to cloud changes, something along the lines of the meridional shifts in the ITCZ (as Stephen Wilde proposes). Some appear to be interpreting solar changes as the 11 year sun spot cycle. ENSO does not have any 11 year signature. It does however (if you look at global or NH smoothed SST) appear to move in 8 year “jumps” (nodes in 1985, 1993, 2001 and 2009). 8 years is Scaffeta’s ocean thermal heat time constant.
izen says: “You cannot ‘create’ warm water from the ENSO process, you have to get energy from somewhere to warm water.”
I’ve described and illustrated this in numerous posts. A couple of questions and answers: Is La Nina part of the ENSO process? The answer is yes. Do the Pacific trade winds increase in strength during a La Nina event? The answer is yes. Do stronger trade winds during the La Nina decrease cloud cover over the tropical Pacific? The answer is yes. Does the decrease in cloud cover during the La Nina allow more Downward Shortwave radiation to warm the tropical Pacific to depth? The answer is yes. Apparently warm water can be “created” by the ENSO process. Are there instances where a La Nina event recharged more tropical Pacific Ocean Heat Content than the preceeding El Nino had discharged? Yup. It happened during the 1973/74/75/76 La Nina, which provided the fuel for the 1982/83 El Nino and it happened during the 1995/96 La Nina, which fueled the 1997/98 El Nino.
http://i56.tinypic.com/a5dhy0.jpg
Just to give you an idea of the magnitudes we’re dealing with, Pavlakis et al (2008) determined the increase in Downward Shortwave Radiation during a La Nina can be as much as +40 watts per square meter over portions of the tropical Pacific.
http://www.atmos-chem-phys-discuss.net/8/6697/2008/acpd-8-6697-2008-print.pdf
You wrote, “The ENSO process is not causal, it is a convenient description of warm/cold ocean currents, a way of parsing ocean processes. Its a reification of measurements, not a primary causal agent.”
The equatorial Pacific Sea Surface Temperature-based ENSO indices (NINO3.4 SST anomalies, ONI, CTI, etc.) do not represent the ENSO process. They illustrate one of the effects of ENSO. They are used do describe the frequency and magnitude of ENSO events, nothing more.
You wrote, “However the last few decades have seen a DECREASE in downward shortwave radiation or TSI. If your hypothesis was right then there would be a step-change DOWN after every El Niño.”
You’ll need to explain the logic behind that. You lost me. Whatever point you’re trying to make is most likely based on your misunderstandings about ENSO.
Jim D says: “Bob, you have probably realized by now from the general theme in the questions that you did not provide an energy balance. When clouds decrease and cause an anomaly warming, they also increase back to the previous cloud cover by the next El Nino causing an equal anomaly cooling…”
The El Nino is releasing heat during that phase in the form of evaporation, which causes the cooling…and the cloud cover.
David Falkner says: “Why adjusted the SST anomalies for volcanoes? I understand why you would for air temperature, but I would think that such a temporary difference would make such a big dent on the ocean.”
The peak effect of Mount Pinatubo on global SST anomalies is about 0.2 deg C. The peak effect of Mount Pinatubo on global Sea+Land Surface temperatures is approximately 0.35 deg C. I’ve never checked the effect on land surface temperatures alone.
Bob, Crispin, Pamela
Thanks for the comments. I have always felt that the key to understanding global temeperature variation is understanding the processes of energy re-distribution in the oceans. It is the ocean that ‘holds’ all the stored energy of the planet surface. And these factors are not well understood – agreed.
My query about the time lag was to be able to try and predict future OHC, SST and also global air temperature variations, if we assume that the sun is indeed going into a low magnetic flux period and that the theory about cloud formation is indeed correct. How would this play out regarding less energy entering the oceans and the then lagged translation of that towards a cooling atmosphere etc. Are there models that integrate the cloud theory and the ENSO effects etc to allow this to be predicted. To date it just seems that everyone states we are going to enter ‘a cooling phase’ ….. but it would be good to quantify this prediction and then see how accurate we are.
Jim D says:
July 10, 2011 at 4:58 pm
“When clouds decrease and cause an anomaly warming, they also increase back to the previous cloud cover by the next El Nino causing an equal anomaly cooling, and the only way it can keep stepping up is for cloud cover never to quite recover between El Ninos.”
Global cloud albedo had continued declining until around 2001 despite ongoing El Ninos. Since then global cloud levels have become stable and even slightly increasing over the period shown below. Hence, the next step up speculation from the recent El Nino during 2009/10 will very likely not occur while global cloud levels remain in this new trend. At least this will be therefore a testable hypothesis with no step up occurring until if global cloud albedo starts decreasing again.
http://img854.imageshack.us/img854/5246/globaltempvglobalcloudb.png