Shifting of the Pacific Decadal Oscillation from its warm mode to cool mode assures global cooling for the next three decades.

Foreword: Don J. Easterbrook sent me this essay on Friday for publication here, but with the dustup over Monckton’s paper and the APS, I decided to hold off publishing it for a bit. For background, see Easterbrook’s web page here. – Anthony

Shifting of the Pacific Decadal Oscillation from its warm mode to cool mode assures global cooling for the next three decades.

Don J. Easterbrook, Dept. of Geology, Western Washington University, Bellingham, WA

Addressing the Washington Policymakers in Seattle, WA, Dr. Don Easterbrook said that shifting of the Pacific Decadal Oscillation (PDO) from its warm mode to its cool mode virtually assures global cooling for the next 25-30 years and means that the global warming of the past 30 years is over. The announcement by NASA that the (PDO) had shifted from its warm mode to its cool mode (Fig. 1) is right on schedule as predicted by past climate and PDO changes (Easterbrook, 2001, 2006, 2007) and is not an oddity superimposed upon and masking the predicted severe warming by the IPCC.  This has significant implications for the future and indicates that the IPCC climate models were wrong in their prediction of global temperatures soaring 1°F per decade for the rest of the century.

Figure 1.  Cooling of the Pacific Ocean and setting up of the cool-mode PDO. Sea surface temperature anomaly in the Pacific Ocean from April 14-21, 2008. The anomaly compares the recent temperatures measured by the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) on NASA’s Aqua satellite with an average of data collected by the NOAA Pathfinder satellites from 1985-1997. Places where the Pacific was cooler than normal are blue, places where temperatures were average are white, and places where the ocean was warmer than normal are red. The cool water anomaly in the center of the image shows the lingering effect of the year-old La Niña. However, the much broader area of cooler-than-average water off the coast of North America from Alaska (top center) to the equator is a classic feature of the cool phase of the Pacific Decadal Oscillation (PDO). The cool waters wrap in a horseshoe shape around a core of warmer-than-average water. (In the warm phase, the pattern is reversed). Unlike El Niño and La Niña, which may occur every 3 to 7 years and last from 6 to 18 months, the PDO can remain in the same phase for 20 to 30 years. (NASA image by Jesse Allen, AMSR-E data processed and provided by Chelle Gentemann and Frank Wentz, Remote Sensing Systems. Caption by Rebecca Lindsey, adapted from a press release from NASA JPL).

Instead of a rise of 1°F during the first decade of this century as predicted by IPCC climate models (Fig 2), global temperatures cooled slightly for the past nine years and cooled more than 1°F this year (Fig 3).  Global cooling over the past decade appears to be due to a global cooling trend set up by the PDO cool mode and a similar shift in the Atlantic. The IPCC’s prediction of a 1° F warming by 2011, will require warming of about 1° F in the next three years and unless that happens, the IPCC models will be proven invalid.

Figure 2.  IPCC predicted warming.

Figure 3.  Measured cooling.

As shown by the historic pattern of PDOs over the past century (Fig. 4) and by corresponding global warming and cooling, the pattern is part of ongoing warm/cool cycles that last 25-30 years. Each time the PDO mode has shifted from warm to cool or cool to warm, the global climate has changed accordingly.  In 1977, the PDO shifted from cool mode to warm mode (Fig. 4) and set off the global warming from 1977 to 1998, often referred to as the “Great Climate Shift.”  The recent shift from PDO warm mode to cool mode is similar to the shift that occurred in the mid-1940’s and resulted in 30 years of global cooling (Fig. 4). The global warming from ~1915 to ~1945 was also brought on by a mode shift in the PDO (Fig. 4).  Every indication points continuation of the PDO patterns of the past century and global cooling for the next 30 years (Fig. 4). Thus, the global warming the Earth has experienced since 1977 appears to be over!

Figure 4.  PDO indices, 1900-2008 with predictions to 2040.


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Pieter Folkens

“indicates that the IPCC climate models were wrong in their prediction”
We’re hearing a lot about that same sort of thing from rational sources in several quarters. Mean while, Prognosticator-in-Chief, Jame Hansen, declares that his 1988 predictions were correct . . . a statement contrary to even his own data set. Then there’s the APS abrupt reaction to an effort to simply open the debate.
Have we reached the point where science based on good data is treated as irrelevant by those who model the future in service of an agenda?
I believe the alarmists are desperately trying to get their Draconian measures in place as soon as possible and before the real cooling sets in so they can claim credit for avoiding unrelenting global warming. The only problem is: will the same people then take personal and professional responsibility for the deleterious effects of global cooing?


Just do not assume that the “prediction” made in the last graphic results from any kind of serious model, statistical or otherwise. Even if the cool phase holds for 30 years, we do not know that it will look like the pattern shown in the graphic.

Tom in Florida

Looks like game, set and match to me.

Figure 3 is marred by a silly smoothing [blue line]. For a reasonable smoothing one would expect as many data points above the blue line as below it. This is indeed the case until 2005, but breaks down after that. The end-point [2008] should not have such a heavy weight. All Figure 3 shows is that there is no clear upward trend over the interval shown. The Figure does not show significant cooling.

Steve Moore

I lived in B’ham in the early 70’s (I worked at Cherry Point; my then-wife was a student at Fairhaven), and I’m amazed that Easterbrook can survive there. I guess the “climate” has shifted considerably — or Fairhaven is an “anomaly”.
His work appears solid. Let’s see what the Warmers will do with it.


I have forwarded the Don Easterbrook article to all my friends. I also discovered this Global Warming Petition Project website and hope a few more who post here will add their names to it.


the predicted portion of the graph is a copy of the period 1945-1977. Looks like a prediction I would make. Seems like a funny way to make a point.

Joe S

“…alarmists are desperately trying to get their Draconian measures in place…”
Pieter, your post reminded me of a piece I read at EU Referendum this morning entitled, “An economic suicide pact”. You might enjoy it. I did.

Hoi Polloi

Climate models predict warming, climate models predict cooling. Why can’t we take the weather as it is, like people have done for kazillion years?

James H

On, Lucia has completed several statistical comparison’s between observed data and IPCC models. They have been falsified (95% confidence). She continued to try more detailed methods to see if they would not falsify (such as a Monte Carlo simulation) and also to suggestions from Gavin Schmidt, but they all falsify the central trend prediction of 2C/century (I don’t recall the uncertainty band, something like +/-2.2C, as provided by the IPCC report). Over the next couple of years, there would actually have to be significantly more warming than 1F to not falsify the models.


…and this cooling will prove global warming, because once it’s cooled. Global warming will come back with a vengance…. and so on and so fort…


Looks like Al is loosing another recount. Reality sucks.
AGW = Al Gore Wishes

The PDO shift was already anticipated by the AGW crowd. Clear the IPCC is doing undermining cries of global cooling from the PDO shift.
While the PDO shift will be enough to convince much of the herd that AGW has been falsified, the real target of the IPCC and AGWers is is global government and control of the global economy.
We can’t just point the declining temperatures then sit back with our laurels and accolades for having foreseen the cooling. We must relentlessly attack the bad science and propaganda of the AGWers otherwise they may succeed in switching the arguments while keeping the same objectives.
Already Gore is trying to change the debate.


I note with dismay that the prediction for the next cooling period matches exactly the cooling period of 1945 / 1977. Can anyone tell me how such blatant copying can possibly help further the cause of those who wish to defeat global-warming alarmism? This graph will instead, I fear, only give ammunition to the Gore disciples. …Or am I missing something?

Mike C

“indicates that the IPCC climate models were wrong in their prediction”
If you guys really wanna see how bad the climate models then go read IPCC Working Group 1, chapter 8.4 “Climate Models and their Evaluation”. Please, don’t take my word for it, it’s right there in writing. Then come back and let me know about a single climate model that can accurately replicate even a fracton of the Earth’s atmosphere and ocean processes that impact climate.

On Topic, on the other hand –
The PDO shift to cooling is heralded (at least when using the Hadley dataset) by a spike in global temperature and then a plateau before a plunge in temperature. This is apparent in the shift to cooling in the early 1900s, somewhat muddled in the 40s and very apparent in 1998.
I believe we are now in the sudden plunge part of things. In a couple of years, the cumulative effect of the deep solar minimum will start to show itself as well.
I am still waiting to collect on a few well placed global cooling wagers that are due in 2010.


I believe the “warmists” are in a panic to get as much of their doctrine codified into law as possible before even the news media has to admit that it isn’t warming and their momentum reverses on them.

Jerker Andersson

“Figure 4. PDO indices, 1900-2008 with predictions to 2040.”
The PDO graph in the end can’t be a prediction, it is just a copy and paste of the cold PDO lasting until 1977 to show how a new cold phase could look like if it was the same as the last one.
Does Don J. Easterbrook actually predict the next cold PDO to look exactly the same as last one? It does not look like a prediction to me.


“I believe the alarmists are desperately trying to get their Draconian measures in place as soon as possible and before the real cooling sets in so they can claim credit for avoiding unrelenting global warming.”
Heh, I just read that after posting my own similar conclusion. I believe it is going to take them by surprise how quickly the dynamic can change when it comes to climate.

Anthony: My internet connection died when I tried to upload this the first time. Hopefully, this is not a duplicate. And, sorry about the length of this, but I actually chopped half of it and added the link to my blogspot.
Don Easterling: I am an AGW skeptic. Keep that in mind while you’re reading these comments. It is not my intent to dispute your work, but I’ve spent a considerable amount of time recently with my head in SST data, and the following is the result of those investigations.
The PDO is not a simple SST residual like the AMO. It is a statistically manufactured index that retrieves the ENSO signal from noisy North Pacific anomaly data. According to Nate Mantua of JISAO, the details of how the PDO is calculated are found in the paper “ENSO-like Interdecadal Variability: 1900–93,” Zhang, Wallace, and Battisti, “Journal of Climate” (1997).
The similarities between the two data sets become apparent in a comparison of monthly and smoothed PDO and NINO3.4 data.
One problem with using the PDO as an indicator of global temperature variation is that the recent PDO “switching point” varies per data set. To illustrate that, the following is a graph of the JISAO PDO data (the most commonly used PDO index) versus the ERSST.v2 and ERSST.v3 PDO data sets. The JISAO PDO goes as far back as 1900, while the two Smith and Reynolds PDOs start in the 1850s. Note that all three data sets fundamentally agree with one another from 1910 to 1980. Prior to and after those years, the two Smith and Reynolds data sets diverge from JISAO. According to the Smith and Reynolds data, the PDO shifted, primarily, to negative around 2000, while the JISAO data changed more recently.
(Note: I believe the divergence between of the ERSST PDO data sets results in part from the fact that JISAO uses three SST data sets when calculating its PDO: UKMO Historical SST from 1900 to 1980, Smith and Reynolds Optimally Interpolated SST Version 1 from 1981 to 2001, and Smith and Reynolds Optimally Interpolated SST Version 2 from 2002 to present.)
Standardization also amplifies the PDO, giving it the appearance of a more robust signal. The mid-latitude (20 to 65N) North Pacific SST anomalies vary considerably less than those indicated by the PDO.
(Note the 0.9 deg C drop in North Pacific SST anomaly from 1888 to 1910. It’s tough to miss. I’ve never seen that mentioned in any discussion of climate change by the IPCC. Those THC/MOC declines occur in all oceans around the same time.)
Another problem with the PDO is, in every reconstruction I’ve seen, its 50- to 60-year cycle disintegrates prior to 1850 to 1900. Refer to the following graph of MacDonald and Biondi PDO Reconstructions. (The way the cycle falls apart is also visible in the longer term ERSST data above.) I’ve excluded the D’Arrigo et al reconstruction from the graph, since they limit its data to Springtime, and the Mann et al PDO reconstruction, because it was prepared by Michael Mann, who I don’t find credible. Will the cycle that existed in the 20th century continue into the current century? No way to predict it based on long-term data.
We need a new SST anomaly index for the North Pacific. Why hasn’t anyone created one that uses the same simple calculation employed for the AMO? It could be used to indicate the impact of the North Pacific on Northern Hemisphere and global temperatures, something we skeptical climate bloggers enjoy. The Mid-Latitude North Pacific Residual (Mid-Latitude North Pacific SST anomaly minus Global SST anomaly) illustrates that there is an oscillation in the North Pacific SST anomaly data, similar in scale to the AMO. Based on the 3-year smoothed data, it recently peaked in mid-2006. Hopefully, the decline will continue.
For illustration purposes, here’s a comparison of the PDO and the North Pacific Residual. Note that the PDO was scaled by a factor of 0.2, illustrating the amplification of standardization.
And a comparison of the AMO and the North Pacific Residual. Note how they were fundamentally in synch after 1920, but in opposition prior to that.
There are a few PDO posts in my blogspot series on Smith and Reynolds SST data.

Meanwhile, Mr. Sun has nary let out a peep now for MONTHS, possibly throwing in a whole new dynamic…

I made up a cumulative PDO graph that shows these change points very clearly, but cannot seem to post it here. Can anyone tell me how to post a graph?

Alan Mitchell: Post your graph on tinypic or where you normally post them and provide a link to it.

Leon Brozyna

I understand Leif’s concerns about Fig 3. I’m viewing that blue line as an extremely oversimplified smoothing used to make a point. I’m guessing this is more directed towards the layman. However, as a skeptic, I’m a bit perturbed in seeing such oversimplification. Give the layman some credit and present it without such extreme smoothing. This sort of presentation could always come back and bite you ~ usually at a most inopportune moment.
As an example, being the information junkie that I am, I frequently check in at Alexa to see how this blog is doing (rather well). I’ve noticed that, as in Fig 3 above, the Alexa graph, with or without smoothing, has the start and end data points fixed. As the days pass and the end point moves in with the rest of the data, its value gets smoothed up or down. It seems also to be the case in Fig 3; the end point is fixed at the latest (monthly?) value, giving it more weight. I would feel more comfortable if Fig 3 had some sort of explanatory statement that the blue line was for illustrative purposes only.
Other than that, a cool phase PDO & a quiet sun with an ever lengthening solar cycle 23 — sounds like a recipe for some mighty cilly years to come.


It looks as if the IPO is still in a bit of a warm phase. When is that one scheduled to heel over?
(Also, on review, I can’t seem to find out what phase the IPO was in from 1998 to date. Can anyone clue me in?)


“Have we reached the point where science based on good data is treated as irrelevant by those who model the future in service of an agenda?”
In my mind and in my car,
We can’t rewind, we’ve gone too far.
Pictures came and broke your heart,
Put the blame on VTR.


I believe the alarmists are desperately trying to get their Draconian measures in place as soon as possible and before the real cooling sets in so they can claim credit for avoiding unrelenting global warming.
You noticed that, huh?
That’s why Bush is crafty like a fox. He approved all these “goals”–for the future. If we are FOAO by the time those goals come due, there ain’t gonna
be no Draconian measures. (That’s why the AGdubya crowd is mad as a wet hen about it.)
The only problem is: will the same people then take personal and professional responsibility for the deleterious effects of global cooing?
How willing was Penrod to take “the Tonic”? How willing was Tom Sawyer to take “the Painkiller”?


We need a new SST anomaly index for the North Pacific.
Doesn’t the IPO more or less fill in the area left out by the PDO?


“This has significant implications for the future and indicates that the IPCC climate models were wrong in their prediction of global temperatures soaring 1°F per decade for the rest of the century.”
Ummm.. where on earth does this come from? The IPCC does not predict a temperature increase of 1C/decade for the next century.
Also, where does Easterbrook derive his prediction of a 30 year cool-phase PDO – well, other than simply saying, the last one was that long? The PDO is not periodic.
Adn also, his conclusion requires that the PDO be a dominant, controlling driver of the earth’s planet. What is his basis for that assumption?


The blue line in Figure 3 may not legitimately show recent cooling, but these do:
Hodrick-Prescott smoothing of the UAH satellite data through June 2008.
I’m not saying that the downturns will continue, and that we can project from them. I’m just saying that there are legitimate techniques for smoothing that show recent cooling.

Looks like some clarification of the PDO projection is needed. This was a presentation to several hundred policymakers (who were not scientists) and I was trying to make the point that we appear to be headed for global cooling rather than catastrophic warming. Each time we’ve had a mode change of the PDO (warm to cool or cool to warm) this century, the global climate has followed suit. NASA’s imagery, showing that the cool-mode PDO has now set up and we are experiencing global cooling, leads to the analogy with past mode switches, e.g., the 1945-1977 cool period. In illustrating the basis for predicting 30 yrs of global cooling, I simply replicated the PDO for the most recent global cooling (~1945-1977). This was intended to be a qualitative projection, shown in the context of why it seems likely. A more scientific way to do this might have been to show a range of possibilities (e.g., deeper cooling, like 1890-1915; still deeper cooling, like 1800; or even deeper cooling, like the Little Ice Age) and smooth out the jagged lines, but this would have tended to obscure the basic idea and take too much time to explain. Please take the diagram for what it was intended, a simple illustration of the basis for predicting global cooling, not a quantitative statistical analysis of data. Those comments that criticized the accuracy of such a prediction are right–the future most likely is not going to be exactly like the last cooling.

Evan Jones: My statement, as you quoted, pertained to the North Pacific. The IPO covers the entire Pacific basin, North and South. They use a 3EOF to calculate it, making a greater product of statistics than the PDO.
What’s wrong with a nice simple residual index, just like the AMO, where you subtract global SST anomaly from the North Pacific SST anomaly? Then all you need is a simple coefficient to determine its impact on Northern Hemisphere and global temperatures. You can’t do that with the PDO or the IPO.

Bill Illis

The most recent SST maps show there is no longer a cool area in the northern Pacific PDO area.
La Nina also appears to be on its last legs and a strong El Nino might develop. The Nino3.4 area is clearly well above average right now and the warmer waters are contining to expand in area.


Mr. Easterbrook:
have you considered the cumulative effect of the six main drivers? Notice the progression from 1977 as one by one they shift to warm.
Interdecadal Pacific Oscillation
1922-1944, warm
1946-1977, cool
1978-1998, warm
[ to date ??? ] — I could use info to fill this in
Antarctic Oscillation (AO)
Pre-1948 – 1980 cool (1950 at max cool)
1980 – date, warm (positive trend since 1960)
Pacific Decadal Oscillation (PDO)
1890-1924, cool
1925-1946, warm
1947-1976, cool
1977-2007, warm
2008 – date, cool
PDO Shifts via tree ring proxies:
1662, 1680, 1696, 1712, 1734, 1758, 1798, 1816, 1923, 1946, and 1977
North Atlantic Oscillation (NAO)
1925 – 1958, warm
1959 – 2000 cool
2001 – date, warm
Arctic Oscillation (AO)
1899 – 1939, warm
1940 – 88, cool
1989 – pres, warm
Atlantic Multidecadal Oscillation (AMO)
1901-1925, cool
1926-1969, warm
1970-1994, cool
1995 – pres, warm
And for good measure:
El Niños (1950-date, -0.5C threshold, yr/mo)
8/51-12/51, 4/57-7/58, 7/63-1/64, 6/65-4/66, 11/68-6/69, 9/69-1/71, 5/72-3/73, 9/76-2/77, 9/77-2/78, 5/82-6/83, 9/86-2/88, 5/91-7/92, 7/94-3/95, 5/97-4/98, 5/02-3/03, 7/04-2/05, 8/06-1/07
La Niñas (1950-date, -0.5C threshold, yr/mo)
(pre)1/50-3/51, 3/54-1/57, 4/64-2/65, 7/70-1/72, 5/73-5/76, 10/84-9/85, 5/88-5/89, 9/95-3/96, 7/98-2/01, 8/07-date

Ron Horvath

Bob those are very intriguing charts and both the AMO and PDO residual are to a high correlation additive during the two principal warming periods during the last 100 years. Give that CO2 concentrations were at odds during these two periods, it pales in comparison as a correlative factor.
Looking at the current period (after 2000), The AMO and PDO appear to be in a subtractive period although one could argue that the path of the AMO residual needs more data points to confirm either way.
I will also check out some of your other links there as well.
On a personal point. I can’t tell you how important you, Anthony and many others who are doing the heavy skeptic lifting. If successful, we who do not have your knowledge and tenacity, will owe you a great debt along with untold millions who will never know the significant efforts that people like you have made in their behalf. No small recipient would be the credibility of science itself. This could be an enormous black eye and more damaging would be the perception in peoples minds of the potential economic harm that could have befallen them if they had signed on with a scientific ‘consensus’ that turned out to closer to a hoax than truth.
For all those who continue the struggle amidst criticism and mockery, never underestimate our appreciation of your importance to us.

For those of you deriding Easterbrook;
AWWWW come-on. Sometimes when someone takes what has happened in history and projects it into the future to underscore a point, they are illustrating what HAS (yeah I’m shouting!) happened, given a situation. If repetative, then more weight has to be given to the hypothesis. Will it occur exactly? Probably not, but the chances of it occuring improve with the number of repetitions. It’s what we’ve been blathering about for some time. Predictions aren’t actuality. Nice thing about history, read correctly it does provide a glimpse of the future. PDO, the activity of the sun and many other factors go into climate change (term used with extreme concern here!).
For those of you who are very literal, read the instruction manual to your lawn mower. Do not use it as a hedge trimmer. Same thing here. What is in the past, is in the past. It may give some idea of what is in the future, but don’t expect the future to be a carbon copy of the past.
Good job Easterbrook!

[…] Shifting of the Pacific Decadal Oscillation from its warm mode to cool mode assures global cooling … Foreword: Don J. Easterbrook sent me this essay on Friday for publication here, but with the dustup over […] […]

Bob B

For those of you castigating people who would dare look at past data and project it into the future—-just look at what Hansen is projecting—a tipping point based off data from millions of years ago—who knows what conditions were really like then?? So taking data from the past 100years of PDO is an issue?? come on AGW people–get a grip!

Jim Arndt

I have one comment on the PDO shift to negative. I see in Figure 4 that the PDO shift was about 1999 or 2000, but it looks like it is closer to 2002 or 2003. If you look at the last negative PDO there are really not any El Nino’s in it, that makes me think the figure 4 should read a PDO shift at 2002 or 2003. Also (Leif will disagree) there was a geomagnetic shift is 2003, the 178.8 barycentric cycle ends close to there and we started the slide to solar minimum. Also if you look at the solar cycle you will have more CME’s and solar flares on the down side of a solar cycle than the up side, this is evident in 2003 to 2006 when temperature remained at a high level and then dropped off after the CME’s and flare subsided. I am of the opinion that CME’s and flares reduce the ability of nuclei to form clouds just like CRF may seed the nuclei. Less clouds one way and more the other. Anyway that is my 2 cents.


Bill Illis,
Are you sure you are right? Seems you are almost outright claiming that the PDO cool phase is either over or never started.
I’m certainly no expert, but experts have recently made claims that the Pacific is starting a cool phase PDO, and your pic looks to me like a classic example of that, with perhaps a little North Pacific Gyre Oscillation thrown in.

[…] 2008 (Manila time), I decided to check a flag from the main site of WordPress, which was about the Shifting of the Pacific Decadal Oscillation from its warm mode to cool mode assures global cooling f… But what caught my attention was what the blogger of Watts Up With That said about a controversy […]

Patrick Henry

No one even knows what the PDO is on a theoretical level. Predictions of cooling are even less likely to be accurate than predictions of warming.
Don’t make the same mistake as the people you criticize.
REPLY: And don’t make the mistake of equating the author’s prediction (Easterbrook) to mine. I published the article, I did not make the prediction. – Anthony


If/when those other cycles come due, flip to cool and start piling on the effects, I wouldn’t be a bit surprised if the trend continues.

Don J. Easterbrook (15:07:58) :
“Looks like some clarification of the PDO projection is needed. This was a presentation to several hundred policymakers (who were not scientists)”

“I simply replicated the PDO for the most recent global cooling (~1945-1977). This was intended to be a qualitative projection, shown in the context of why it seems likely.”
I figured as much, however, a recent thread here discussed creating data out of thin air so that statistical models should work with more readily. One example was a station that was shut down at one point in time but data for it was created for the next several years, possibly from averages of surrounding stations.
That was considered abuse of data by posters here, and is fundamentally no different than your figure 3.
“Please take the diagram for what it was intended, a simple illustration of the basis for predicting global cooling, not a quantitative statistical analysis of data.”
While we don’t live up to the mathematical standards of, or live down to the standards of policy makers, we are members of PETD, People for the Ethical Treatment of Data, and while data should be used, it shouldn’t be reused inappropriately. 🙂


Those of us who have been following the debate for years will remember that in 2000, some sceptics were anouncing that the PDO had switched, only to see it to jump back up into warm phase in 2002. Now PDO is dropping again, I think it is a bit reckless to predict that this time it will stick, especially as it has not been negative for as long as it was in 2000-01.
If you look at the history, there has been a grand total of one clearcut switch from warm to cool. This is not much of a statistical sample on which to base a cycle. We should be just as hesitant about predictions that confirm our beliefs as ones that don’t. Just remember that our best solar scientists really don’t have a clue when the next solar cycle will begin, even though they have been studying the sun through 23 unambiguous cycles.


Bill Innis…
Your statements are a bit premature. In fact, the basic -PDO signature is still intact, it is just weaker (as it often will be during summer) and since the La Nina has faded. The PDO/multi-decadal climate shifts are so much more than just SSTAs at a certain point in time, they have to do with global circulation, atmospheric conditions, currents, etc.
And a strong El Nino will not develop for this winter, I guarantee that.


Re: Figure 3. I am glad Leif and Leon have already discussed the blue line, however I can’t immeadiately see how it results from smoothing given the end point of the blue line is below the last point in the data (and indeed any point in the data). How *exactly* was the blue line generated?
Having looked at the “global cooling data”, as far as I can see there is no cooling since 2002 unless you include the last year and a bit of data, e.g the trend is flat from 2002-2006 is flat, for example see
We should not be making long-term predictions on global cooling that depends so strongly on a single years observations.
Also the 2002 start seems cherry picking, as it is starting the graph at an El-Nino period and ending it at a La Nina, why not start say in 2000, so including a whole ENSO cycle rather than a half-cycle?
(possibly because you get a warming trend).


I see now that the end of the blue line is exactly on the last data point. Presumably that means that the same graph computed 18 months ago would have shown exponential warming instead?


I think many people forget that the PDO wasn’t “discovered” by oceanographers or climate scientists, but by fishermen. Of course, they didn’t call it the Pacific Decadal Oscillation. For decades fishermen along the west coast noticed that cetain species of fish such as Perch migrated north and south. Biologists at the University of Washington discovered that these species were temperature sensitive and that thier migration patterns were dependent upon SSTs. I believe it wasn’t until 1997 that the PDO was fomerly defined. To say the PDO is only a statistical fabrication ignores the fact that there is a physical manisfestation of it, and it can be verified by observing the migration patterns of temperature sensitive fish.
Also, it should be noted that scientists in 1976 were surprised as anyone during the 1976 El Nino event when they noticed that “normally” cool SSTs off the coast of North America warmed a bit and stayed warm after the El Nino event went neutral. It wasn’t a large anomally, but it did catch some scientist’s eye. They knew sometthing fundementally changed and dubbed this warming the Great Pacific Climate Shift. Whether the PDO is a risidual as robust as the AMO or NAO I think misses the point. The PDO is important to both biologists and climate scientists. It isn’t difficult to coorelate global temperature anomalies to the phase of the PDO, nor is it too difficult to coorelate the patterns in ENSO to it.
People can still disagree witht the importance of the PDO to global climate, but the disagreement should center around the fact that a)no one yet can forecast ENSO events with any degree of precisions, b)We do not know with any certainty what the causes of ENSO are and c)What the true relationship of the PDO to ENSO really is. We also have only a tiny data base of SSTs that can be considered precise (less than 50 years), and must guess at past weather patterns. We have no idea what ENSO and the PDO were like during the LIA or MWP, and consequently have no way of knowing what was driving the Pacific Basin weather/ocean patterns from 850-1850.
What has consistently upset many sceptics is that just 30 years ago significant discoveries were made in the field of atmosphereic sciences, and those discoveries are now being overcome by the AGW narrative. We are lectured constantly that GHG concentrations drive everything -even ENSO. Everything is being subordinated to a trace gase called CO2. Until last year this narrative held firm. What sceptics should continue to remind everyone is the fact that ENSO still appears to be the main driving force of our climate based upon real, emprical evidence. The cooling we’ve seen in the last 15 months was not forecasted by the GCMs. The PDO shift expectations is based up concrete evidence of past SSTs, and global surface temperature trends. Of course, Mother Nature is full of surprises. Whether the current negative PDO will act like the last phase is anyone’s guess.


One last item to consider is the strength of the 2007-2008 La Nina in relation to the 2006 El Nino. The 2006 El Nino event was fairly weak and short lived (Using NOOA’s MEI);however, in a fairly short time (3 months) ENSO went neutral, and by later Spring the La Nina formed and evolved into a fairly intense event. The last strong La Nina (1999-2000) followed in the wake of a Super El Nino (1997-1998). What makes this last La Nina interesting is that it wasn’t created in the wake of a intense El Nino (usually Rossby waves rebounding off the coast of the Americas westwards. A classic PDO signal is the dominance of La Nina events over a period of 2-3 decades. The false positives of the 2000-2002 years could be attributed to an intense ENSO cycle (Super El Nino/Strong La Nina). The 2006-2008 ENSO cycle was something entirely different.