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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Great work, but I’d like to hear more about the La Niña epochs where, according to the phrase I highlighted in bold, the opposite (i.e., SST reduction) is expected to take place.
You have neatly demonstrated that 1/3 of the ocean surface (East Pacific) does not seem to have warmed at all over the past three decades, according to the SST data set.
However, the other 2/3 of the ocean surface (the Rest of the World) seems to have risen in mean temperature by about 0.3ºC over the same period, albeit in steps synchronized to El Niño events.
Thus, over three ENSO cycles, the overall global mean SST has gone up by about 0.2ºC. Due to what?
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. In fact I can see the same steps on that graph as the ones you present on the ‘rest of the world’ one, but in my opinion it’s just too noisy to draw any conclusions. And if it’s El Nino what’s adding to the temperature, where’s the force that’s keeping it constant in between? Shouldn’t it be returning to ‘balanced state’ if there was no such force? Or is it rather like that a steps-like graph can be created as a sum of a see-saw graph and a slope?
Should not the after effects of El Ninos diminish as one gets increasingly distant from each event in time? I doubt that the steps result in permanent shifts that build upon each other ad infinitum. In addition to that, surely there is a phenomenon or set of circumstances that result in downward jumps, but according to your posts on La Nina, that can’t be what would do that. So what phenomenon results in multidecadal and longer cooling trends?
“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.”
I expect the recent step to be short lived.
I hope they appeal to the Inter-Academy Council (IAC) to reconvene and issue opinions on the IPCC’s latest outrages.
(Not applying conflict-of-interest rules; Issuing a hyped-up, NGO-written renewables press release & report; Fiddling with the contents of a peer reviewed paper to increase the climate sensitivity figure.)
Ira Glickstein, PhD says:
July 10, 2011 at 10:14 am
Thus, over three ENSO cycles, the overall global mean SST has gone up by about 0.2ºC. Due to what?
The accumulation of solar derived energy in the upper ocean, due partly to higher than average solar activity over the period, and partly to reduced cloud cover over the tropics.
Yes, the impact of an el nino event ought to diminish with time, say, decay away exponentially like a leaky integrator, but its effects are coupled into other factors that also “integrate” the effect. For instance, el nino humidifies the atmosphere, this in turn acts as additional “green house” warming and might alter precipitation patterns, then perhaps alters albedo, and so on…what is the time scale of these integrators? I dunno. No one else does either. It could be anything from decadal to millenial. This is why I find Tisdale’s suggestions so interesting. They are full of other possibilities.
Yes, but where’s the cooling in between the steps?
Oceans heat up quickly and cool down slowly. The steps would follow this pattern. More frequent warming periods would lead to step increases. I would hazard a guess that when El Nino’s dominate, steps up without falling back to baseline would dominate SST data. When La Nina’s dominate, steps down to eventual baseline and below would dominate SST data.
While this post asks some interesting questions, we don’t really understand what is going on here (yet).
If I may, for a moment, play devil’s advocate, let me hypothesise this:
1. A constant(ish) positive forcing exists (e.g. CO2)
2. While the new energy is entering the system, some unknown damping factor prevents it from warming the SST. The energy must be stored elsewhere (Where???)
3. At the end of an El Nino cycle, the damping temporarily releases and the stored energy warms the SST.
4. The damping then returns and the cycle continues.
Now the above is complete speculation but I propose it as a thought experiment to help us consider if Mr Tisdale’s work actually disproves AGW. Is such a system feasible? Can anybody improve upon it to make it feasible?
Of course feasible doesn’t mean true, but if we can imagine a situation where Mr Tisdale’s analysis could coexist with AGW, then we have not yet disproved it.
Bob,
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.
If you haven’t noticed then I take credit for noticing 🙂
Michael J says:
July 10, 2011 at 11:39 am
While this post asks some interesting questions, we don’t really understand what is going on here (yet).
If I may, for a moment, play devil’s advocate, let me hypothesise this:
1. A constant(ish) positive forcing exists (e.g. CO2)
2. While the new energy is entering the system, some unknown damping factor prevents it from warming the SST. The energy must be stored elsewhere (Where???)
3. At the end of an El Nino cycle, the damping temporarily releases and the stored energy warms the SST.
4. The damping then returns and the cycle continues.
Now the above is complete speculation but I propose it as a thought experiment to help us consider if Mr Tisdale’s work actually disproves AGW. Is such a system feasible? Can anybody improve upon it to make it feasible?
Of course feasible doesn’t mean true, but if we can imagine a situation where Mr Tisdale’s analysis could coexist with AGW, then we have not yet disproved it.
____
Yes, there are many ways in which AGW can “coexist” with Bob’s analysis, and your thought experiment is headed in the right direction. Assuming there aren’t other flaws in Bob’s analysis, his underlying assumption is that AGW will be seen in the narrow range and conditional SST parameters he’s created, and furthermore, that no signal from AGW is part of the “stepwise” incremental increase in SST’s related to the EL Nino events. Finally, his analysis includes no discussion as to the association between SST’s, which fluctuate based on many causal factors, and total Ocean Heat Content, which, even though only currently measuring down to 700m, shows a much more steady rise over his period of analysis. You asked in question #2 if the energy must be stored somewhere, and the answer may be the deeper oceans. See:
http://journals.ametsoc.org/doi/abs/10.1175/2010JCLI3682.1
In short, Bob’s analysis, while interesting, in no way disproves the contention that the rapid increases in CO2 over the past few centuries is affecting the earth’s energy budget, and until we see the expect step-wise decrease in SST’s that would have to occur if this is a natural cyclical phenomenon, we still have more heat even in the surface SST’s (not to mention the deeper warming as referenced above) than we had at the beginning of the analysis period.
PJB says: “If the sun goes “quiet” for an extended period (several decades at least) then would it be reasonable to assume that the radiative driver would favor La Nina episodes and that the step-wise graph would continue, but with the opposite slope?”
I’ve never seen any papers that support this. On the other hand, I’ve never seen any papers that acknowledge the upward steps over the past 20+ years.
walt man says: “To suggest that there is no AGW you should have an explanation for the steps.”
I have. They’re discussed in detail in the posts linked under the heading of FURTHER INFORMATION.
Stephen Wilde says: “Agreed but what about trends from one El Nino dominated multidecadal era to the next?”
As discussed on numerous threads before this, I do not study paleoclimatological data. In fact, I spend most of my efforts with satellite-era data because there’s better coverage.
Grant says: “Where does the heat for these el niño events come from?”
The warm water that fuels an El Nino is “stored” in an area of the western Tropical Pacific called the Pacific Warm Pool. The trade winds “pile it up” there. During an El Nino, the trade winds relax and the warm water (surface and subsurface) sloshes east. During the La Nina, the trade winds strengthen and return leftover warm water to the surface of the western Pacific. It gets distributed poleward and into the Indian Ocean from there. Also during the La Nina, stronger trade winds reduce cloud cover, which allows more sunlight to warm the tropical Pacific to depth, and through that increase in sunlight, the La Nina recharges the warm water in the Pacific Warm Pool for the next El Nino.
Refer to:
http://bobtisdale.blogspot.com/2010/08/introduction-to-enso-amo-and-pdo-part-1.html
Monbiot’s mum says: “Looking at figure 4, following the 1998 el nino, we never then went below (or got near) the previous baseline, the green line. Following the recent el nino, we are possibly going to go below the previous baseline (the brown line)…”
The 2009/10 El Nino was weaker than the 1997/98 El Nino. If, big if, there’s another upward step, it should not be as large as the one in 1997/98.
Seems to me there is something going on here related to the thermohaline current (THC). ENSO could be driven by changes in the 1600 year flow starting in the North Atlantic. What was going on 1600 years ago in the North Atlantic in terms of temperature, and what effect might that have had on what we observe today? The time error bars are probably pretty big (1600 +/- 200 or more?). If many cubic km of water are spreading out on the surface, a slow deep current can affect a large area. It may be we are seeing the effects of faster versus slower THC, larger versus smaller volume, or perhaps warmer versus colder current. More cold water upwelling could keep the SST lower, i.e. a bigger La Niña. Less might make El Niño dominate. Perhaps we are seeing the delayed effects of reduced evaporation of the waters of the Atlantic during the Dark Ages.
I found a paper with excellent discussion of THC issues. It has models and IPCC (my first reaction was “ick”), but it also has GCRs. It discusses technology to get answers. It seems to be balanced, and looking for answers.
http://www.ifm.zmaw.de/fileadmin/files/images/Staff/Quadfasel/8MSFfE_meincke.pdf
R.M.B. says:
July 10, 2011 at 8:26 am
Heat from a molecule of “greenhouse gas” can not warm the ocean and the reason is surface tension.The ocean will not accept physical heat only radiation.
Surely if the ocean is absorbing the greenhouse gas it must be absorbing its heat with it?
steveta_uk says: “But you don’t attempt to explain where the additional energy comes from that triggers the step changes….”
Actually, I have, just not in this post. I’ve been documenting, illustrating, discussing, and animating the reasons why the East Indian and West Pacific Oceans rise in apparent steps in response to those El Nino events. Some of the posts are provided above in the links under the heading of FURTHER DISCUSSION. The North Atlantic also experiences these upward steps, which are what one would expect with an extended response to ENSO laid on top of the additional upward trend of the AMO for the past three-plus decades.
The most recent peak is barely above the previous, so I would not expect much of an upward step at all.
Pamela Gray says:
Oceans heat up quickly and cool down slowly. The steps would follow this pattern. More frequent warming periods would lead to step increases. I would hazard a guess that when El Nino’s dominate, steps up without falling back to baseline would dominate SST data. When La Nina’s dominate, steps down to eventual baseline and below would dominate SST data.
+++++
Agreed, Pamela. Can we not use the movement of the solar barycenter and its correlation to solar activity to project back to the 1600 to gain some understanding of the time it takes for this to happen?
Suppose Svensmark is correct. The 10Be deposition rate yields the GCR intensity. The rate of change of the acceleration of the centre of gravity of the sun (not its diameter) around the barycentre correlates well with the magnetic activity (as I read it). So from two completely different inputs it should be possible to derive some general case formula that will predict El Nino’s. That was what Landsheidt did so well and Corbyn continues to do (with more resolution), but both forward and backward.
The El Nino ‘heat decay rate’ should then be extractable, and the gentle temperature rise out of the last ice age detected by simple subtraction. Any change from that final set of sums over the past 60 years would be the AG portion, minus any natural rise in CO2 other GHS’s as a result of ice age and mini-ice age retreat.
From the appearance of things now, if things go normally, Greenland will continue to melt slowly for perhaps 500,000 years and the Northern Forests, Fauna and Fisheries will return to their former glory.
Bob, with regard to La Nina you say that cloudiness decreases to allow more solar energy into the ocean to enhance the recharge process.
Is that simply a regional effect involving a shift in the position of the ITCZ?
I ask because cooler ocean surfaces during a La Nina would shrink the width of the tropical air masses, weaken the subtropical high pressure cells and allow more meridional jetstreams with increased cloudiness globally notwithstanding the opposite effect over the ENSO region itself.
Could the global effect on cloudiness be opposite to the regional effect?
HaroldW says: “Are you saying that El Nino directly ‘provides’ that energy?”
ENSO provides that energy, not necessarily the El Niño phase. The El Niño phase of ENSO raises the global surface temperatures in a number of ways. But the La Niña phase (during the significant El Niño/La Niña events) is what maintains the global surface temperatures at the elevated levels.
1. The La Niña event returns leftover warm water from the El Niño back the surface of the western Tropical Pacific, due to a resumption of the trade winds and a phenomenon called a Rossby wave.
2. The La Niña event distributes that leftover warm water poleward in the western Pacific and distributes it into the East Indian Ocean,
3. Due to an increase in the strength of the trade winds during the La Niña, cloud cover is reduced over the tropical Pacific, which allows more Downward Shortwave Radiation (visible sunlight) to warm the tropical Pacific to depth, recharging the ocean heat released during the El Nino.
4, The increased strength of the trade winds and the increase in Downward Shortwave Radiation during the La Nina also allows more warm water than normal to be distributed poleward and into the Eastern Indian Ocean.
El Niño gets all of the coverage, but there’s lots more going on during the La Niña.
I illustrated the processes in the following YouTube videos:
And:
They’re from this post:
http://bobtisdale.wordpress.com/2010/06/10/la-nina-is-not-the-opposite-of-el-nino-%e2%80%93-the-videos/
If these step ups from El Nino’s illustrated on the main topic of this thread don’t contribute to overall global temperatures long term, then we would expect no increased long term trend overall in the NINO3.4 region. The NINO3.4 surface temperatures from 1900 to the present day are shown below from ERSSTv3b.
http://img651.imageshack.us/img651/963/nino34.png
From the 1900’s up to the 2000’s surface ocean temperatures on average have risen 0.8c in the region of NINO3.4.
The graph below shows the global temperatures warming and cooling corresponding with NINO3.4.
http://img198.imageshack.us/img198/3726/had3vnino34.png
Since 1900 there has been so far 4 different phases with different trending ENSO. (the first one is only partly shown) The periods above 0.5c have been increasing while at the same time periods below -0.5c decreasing. This explains why the cooling period between the 1940’s and 1970’s didn’t decline to previous global levels around the early 1900’s and 1910’s.
Finally the graph below shows how the warming trend of the NINO3.4 matches the trends in global temperatures very well.
http://img577.imageshack.us/img577/7039/had3vpdovnino34.png
The first and last 5 years use a 13 month filter while the rest 121-month one.