UPDATE 1/28: Full text of Dr. Theon’s letter has been post on the Senate website and below.
This is something I thought I’d never see. This press release today is from the Senate EPW blog of Jame Inhofe. The scientist making the claims in the headline, Dr. John S. Theon, formerly of the Institute for Global Environmental Strategies, Arlington, Virginia, has a paper here in the AMS BAMS that you may also find interesting. Other papers are available here in Google Scholar. He also worked on the report of the Space Shuttle Challenger accident report and according to that document was a significant contributor to weather forecasting improvements:
The Space Shuttle Weather Forecasting Advisory Panel, chaired by Dr. John Theon, was established by NASA Headquarters to review existing weather support capabilities and plans and to recommend a course of action to the NSTS Program. Included on the panel were representatives from NASA, the National Oceanic and Atmospheric Administration (NOAA), the Air Force, and the National Center for Atmospheric Research.
For those just joining the climate discussion, Dr. James Hansen is the chief climate scientist at NASA Goddard Institute for Space Studies (GISS) and is the man who originally raised the alarm on global warming in 1988 in an appearance before congress. He is also the keeper of the most often cited climate data.
EPW press release below – Anthony
Washington DC, Jan 27th 2009: NASA warming scientist James Hansen, one of former Vice-President Al Gore’s closest allies in the promotion of man-made global warming fears, is being publicly rebuked by his former supervisor at NASA.
Retired senior NASA atmospheric scientist, Dr. John S. Theon, the former supervisor of James Hansen, NASA’s vocal man-made global warming fear soothsayer, has now publicly declared himself a skeptic and declared that Hansen “embarrassed NASA” with his alarming climate claims and said Hansen was “was never muzzled.” Theon joins the rapidly growing ranks of international scientists abandoning the promotion of man-made global warming fears.
“I appreciate the opportunity to add my name to those who disagree that global warming is man made,” Theon wrote to the Minority Office at the Environment and Public Works Committee on January 15, 2009. “I was, in effect, Hansen’s supervisor because I had to justify his funding, allocate his resources, and evaluate his results,” Theon, the former Chief of the Climate Processes Research Program at NASA Headquarters and former Chief of the Atmospheric Dynamics & Radiation Branch explained.
“Hansen was never muzzled even though he violated NASA’s official agency position on climate forecasting (i.e., we did not know enough to forecast climate change or mankind’s effect on it). Hansen thus embarrassed NASA by coming out with his claims of global warming in 1988 in his testimony before Congress,” Theon wrote. [Note: NASA scientist James Hansen has created worldwide media frenzy with his dire climate warning, his call for trials against those who dissent against man-made global warming fear, and his claims that he was allegedly muzzled by the Bush administration despite doing 1,400 on-the-job media interviews! – See: Don’t Panic Over Predictions of Climate Doom – Get the Facts on James Hansen – UK Register: Veteran climate scientist says ‘lock up the oil men’ – June 23, 2008 & UK Guardian: NASA scientist calls for putting oil firm chiefs on trial for ‘high crimes against humanity’ for spreading doubt about man-made global warming – June 23, 2008 ]
Theon declared “climate models are useless.” “My own belief concerning anthropogenic climate change is that the models do not realistically simulate the climate system because there are many very important sub-grid scale processes that the models either replicate poorly or completely omit,” Theon explained. “Furthermore, some scientists have manipulated the observed data to justify their model results. In doing so, they neither explain what they have modified in the observations, nor explain how they did it. They have resisted making their work transparent so that it can be replicated independently by other scientists. This is clearly contrary to how science should be done. Thus there is no rational justification for using climate model forecasts to determine public policy,” he added.
“As Chief of several of NASA Headquarters’ programs (1982-94), an SES position, I was responsible for all weather and climate research in the entire agency, including the research work by James Hansen, Roy Spencer, Joanne Simpson, and several hundred other scientists at NASA field centers, in academia, and in the private sector who worked on climate research,” Theon wrote of his career. “This required a thorough understanding of the state of the science. I have kept up with climate science since retiring by reading books and journal articles,” Theon added. (LINK) Theon also co-authored the book “Advances in Remote Sensing Retrieval Methods.” [Note: Theon joins many current and former NASA scientists in dissenting from man-made climate fears. A small sampling includes: Aerospace engineer and physicist Dr. Michael Griffin, the former top administrator of NASA, Atmospheric Scientist Dr. Joanne Simpson, the first woman in the world to receive a PhD in meteorology, and formerly of NASA, Geophysicist Dr. Phil Chapman, an astronautical engineer and former NASA astronaut, Award-Winning NASA Astronaut/Geologist and Moonwalker Jack Schmitt, Award-winning NASA Astronaut and Physicist Walter Cunningham of NASA’s Apollo 7, Chemist and Nuclear Engineer Robert DeFayette was formerly with NASA’s Plum Brook Reactor, Hungarian Ferenc Miskolczi, an atmospheric physicist with 30 years of experience and a former researcher with NASA’s Ames Research Center, Climatologist Dr. John Christy, Climatologist Dr. Roy W. Spencer, Atmospheric Scientist Ross Hays of NASA’s Columbia Scientific Balloon Facility]
Gore faces a much different scientific climate in 2009 than the one he faced in 2006 when his film “An Inconvenient Truth” was released. According to satellite data, the Earth has cooled since Gore’s film was released, Antarctic sea ice extent has grown to record levels, sea level rise has slowed, ocean temperatures have failed to warm, and more and more scientists have publicly declared their dissent from man-made climate fears as peer-reviewed studies continue to man-made counter warming fears. [See: Peer-Reviewed Study challenges ‘notion that human emissions are responsible for global warming’ & New Peer-Reviewed Scientific Studies Chill Global Warming Fears ]
“Vice President Gore and the other promoters of man-made climate fears endless claims that the “debate is over” appear to be ignoring scientific reality,” Senator James Inhofe, Ranking Member of the Environment & Public Works Committee.
A U.S. Senate Minority Report released in December 2008 details over 650 international scientists who are dissenting from man-made global warming fears promoted by the UN and yourself. Many of the scientists profiled are former UN IPCC scientists and former believers in man-made climate change that have reversed their views in recent years. The report continues to grow almost daily. We have just received a request from an Italian scientist, and a Czech scientist to join the 650 dissenting scientists report. A chemist from the U.S. Naval Academy is about to be added, and more Japanese scientists are dissenting. Finally, many more meteorologists will be added and another former UN IPCC scientist is about to be included. These scientists are openly rebelling against the climate orthodoxy promoted by Gore and the UN IPCC.
The prestigious International Geological Congress, dubbed the geologists’ equivalent of the Olympic Games, was held in Norway in August 2008 and prominently featured the voices of scientists skeptical of man-made global warming fears. Reports from the conference found that Skeptical scientists overwhelmed the meeting, with ‘2/3 of presenters and question-askers hostile to, even dismissive of, the UN IPCC’ ( See full reports here & here ] In addition, a 2008 canvass of more than 51,000 Canadian scientists revealed 68% disagree that global warming science is “settled.” A November 25, 2008, article in Politico noted that a “growing accumulation” of science is challenging warming fears, and added that the “science behind global warming may still be too shaky to warrant cap-and-trade legislation.” More evidence that the global warming fear machine is breaking down. Russian scientists “rejected the very idea that carbon dioxide may be responsible for global warming”. An American Physical Society editor conceded that a “considerable presence” of scientific skeptics exists. An International team of scientists countered the UN IPCC, declaring: “Nature, Not Human Activity, Rules the Climate”. India Issued a report challenging global warming fears. International Scientists demanded the UN IPCC “be called to account and cease its deceptive practices.”
The scientists and peer-reviewed studies countering climate claims are the key reason that the U.S. public has grown ever more skeptical of man-made climate doom predictions. [See: Global warming ranks dead last, 20 out of 20 in new Pew survey. Pew Survey: & Survey finds majority of U.S. Voters – ‘51% – now believe that humans are not the predominant cause of climate change’ – January 20, 2009 – Rasmussen Reports ]
The chorus of skeptical scientific voices grow louder in 2008 as a steady stream of peer-reviewed studies, analyses, real world data and inconvenient developments challenged the UN’s and former Vice President Al Gore’s claims that the “science is settled” and there is a “consensus.”
On a range of issues, 2008 proved to be challenging for the promoters of man-made climate fears. Promoters of anthropogenic warming fears endured the following: Global temperatures failing to warm; Peer-reviewed studies predicting a continued lack of warming; a failed attempt to revive the discredited “Hockey Stick“; inconvenient developments and studies regarding rising CO2; the Spotless Sun; Clouds; Antarctica; the Arctic; Greenland’s ice; Mount Kilimanjaro; Global sea ice; Causes of Hurricanes; Extreme Storms; Extinctions; Floods; Droughts; Ocean Acidification; Polar Bears; Extreme weather deaths; Frogs; lack of atmospheric dust; Malaria; the failure of oceans to warm and rise as predicted.
# # #
ORIGINAL FULL TEXT LETTER SENT VIA EMAILS:
From: Jtheon [mailto:jtheon@XXXXXXX]
Sent: Thursday, January 15, 2009 10:05 PM
To: Morano, Marc (EPW)
Sent: Tuesday, January 13, 2009 12:50 PM
To: Morano, Marc (EPW)
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Simon Evans #10 31 04
I have the answers to your questions from the man himself with whom I correspond frequently. It is distinctly OT here. Could you go to the new CO2 thread article by Frank Lanser and let me know you have read this and I will post Becks and my reply.
Smokey-you had an interest in this data as well I think
TonyB
leif
The temperatures from 1880-1976 are driven by more than just the sun as we have pointed out in previous posts . PDO ,AMO and ENSO effects seem to modify the solar activity . Of these PDO seems to have the greatest effect. So one cannot say just because the solar activity and temperature follow one another that the temperature rise is only due to the sun activity alone . In canada 8 out of the 10 coldest annual temperature departures from the 1948 -2008 took place when the PDO went negative 1944-1976. Co2 was rising. Solar activity was high. Temperatures were dropping. Similar pattern was about 1878 -1920
Old construction worker:
“Where in nature is wapor vapor a positive feedback to “heat”?”
Exactly my point at the start of that post. Then there’s latent heat of vapourisation to consider (540cal/gm).
If anyone wants to know about positive feedback, pull the plug on the amplifier and listen!
A reply to me previous post had: “the situation is complex, but.” I don’t like “complex, but”‘s. Sort of an invitation to stop thinking (no chance!)
Smokey:
And Simon Evans, I just don’t know how to make you happy.
He aint happy: he aint going to be made happy: he doesn’t do happy.
There is no such thing as a happy greenie/AGWer.
Leif Svalgaard,
Thank you for the answer to my question and for pointing out that “climate” and the Sun’s output are not directly connected. I can follow that the complicated interaction between all the elements of the climate are “mostly not controlled by the Sun”, although it is difficult to give up on some modernized notion of cycles (e.g., Milankovitch) “driven” by the earth’s relationship to the sun and the variations of solar output. I am concerned about the idea of “forcings” as if they somehow generate heat themselves — as it seems that Hansen and crew believe. My limited science says that all heat/energy, however distributed on earth, must come from the sun or the earth’s core; anything else is like magic — or corrupt politics (financial instruments representing wealth created out of bad debts?
matt v: You wrote, “PDO ,AMO and ENSO effects seem to modify the solar activity . Of these PDO seems to have the greatest effect.”
Your first sentence appears to be worded poorly, since it’s unlikely that oceanic oscillations on Earth would alter solar activity. Regardless… The PDO is a “statistically manufactured” dataset that was first created to bring out the ENSO signal in the North Pacific.
http://bobtisdale.blogspot.com/2008/06/common-misunderstanding-about-pdo.html
If you were to plot the raw NINO3.4 & PDO side-by-side, you’d see the similarities.
http://bobtisdale.blogspot.com/2008/06/chicken-or-egg-pdo-or-enso.html
http://bobtisdale.blogspot.com/2008/06/three-pdo-data-sets.html
The PDO, in and of itself, really describes a pattern of SST. It is not an SST residual like the AMO. http://bobtisdale.blogspot.com/2008/06/amo-versus-mid-latitude-north-pacific.html
Regards
BOB Tisdale
You are right about the poor use of words . I meant to say that the impact of PDO[Changing pacific water temperatures whether negative or positive ] on global surface temperatures seem to reduce or enhance the impact of solar activity on earth’s global temperatures .
matt v. (11:27:33) :
The temperatures from 1880-1976 are driven by more than just the sun as we have pointed out in previous posts
Perhaps I was not being clear enough: You are not arguing with me. I don’t believe any of that argument I presented. It is the argument [and it is strong] that AGWers uses to explain why temperatures changed before the big CO2 push the last 40 years. I’ll try again: IF you believe that solar activity is a MAJOR driver, then you do need something [think CO2] else driving up the temperature during 1990-2006 [or so]. If you don’t believe that the Sun is a major driver, then you don’t need CO2 [actually CO2 won’t work because climate also changed in the past]. If you don’t believe it is CO2, then you can’t argue that the changes are due to the Sun [mostly], but will have to invoke other things [and there are lots].
Smokey,
It’s not worth my trying to respond to the ranting or the CEI-like “some call it pollution, we call it life” part of your post. But I will give you an answer to this…
Whoops…Bad HTML coding! Everything after the “(1)” are my words, not Smokey’s.
Michael D Smith says:
Let’s not create some fiction that Milloy is some unbiased arbiter of junk science. His criterion for judging science to be junk is merely that it could be used to support environmental or health regulations. Nothing more, nothing less.
matt v: The PDO, whether positive or negative, does not represent SST or SST anomalies of the North Pacific. The PDO is not a typical residual either.
With regards to the timing of ENSO events and Solar Cylces, sometimes the Solar Cycles enhance the El Nino or La Nina, and sometimes they retard it. Here’s a gif animation that overlays the impact of solar onto a curve that synthesizes global temperature anomaly. The red curve is created from a running total of NINO3.4 SST anomalies that have been scaled to represent the impact of ENSO events on global temperature.
http://i42.tinypic.com/k50pd0.jpg
PaulHClark says:
No problem. Glad that I could help.
I think there is little doubt that Lindzen is an outstanding atmospheric scientist. And, maybe the word “fringe” is a bit too loaded. But, just because someone is a very good scientist does not make them infallible and the fact is that he is really out on the edge in the climate science field … And, for someone as smart as he is, I think that he has shown some very poor judgment in some of the arguments he has made or allowed himself to be associated with in the popular media.
I tried to give you a rough outline of some of the evidence. However, if you really want to look into it, I suggest reading the appropriate sections of the IPCC reports. The problem is that many people want some sort of “smoking gun” but the fact is that in any field anywhere near the forefront of science, you are not likely to have anything like that. What you are going to have is a lot of evidence to wade through, some of it contradictory or uncertain but most of it in the end pointing in one direction.
As I have pointed out before, this lack of absolute proof in science is the sort of thing that allows people to earnestly believe that the Earth is less than 10000 years old, including some with PhDs in science. (I actually had a fellow scientist at work sincerely start telling me at lunch one day about the wealth of evidence for a “young earth”…I nearly spit out my food.)
By the way, I am not claiming that believing in a low climate sensitivity is as scientifically-unjustified at this point as believing in a young earth…although I think believing in the major conclusions of the G&T paper or believing that most of the current CO2 rise isn’t due to humans probably is at least quite close.
I did get a little lazy there but the fact is that you linked to a long diatribe from the junkscience.com site without even noting which parts enticed you. Frankly, I don’t have the energy to go through and try to debunk all the standard “skeptic” talking points that are in there. So, I did take the shortcut in that case in pointing out that what you linked to is simply not considered a serious or reputable source by the scientific community. Rather, it is advocacy masquerading as science. And, I think you’d admit that if those of us in the minority viewpoint on this Board started linking to Greenpeace or Sierra Club as scientific sources, not very many people here would buy into that approach.
Leif: if you turn the sun off the earths surface temperature falls to -273K (except close to magma openings ect ie volcanoes active, which also could die off without the sun possibly?). It follows that any changes in sun activity be it geomagnetic tsi ect would likely affect climate. Sunspot num despite its ups and down closely correlates with averaged global temps over the last 100 years
Smokey says:
Thanks for the link. And, while you could perhaps quibble with my wording, I don’t think the gist of my statement is really incorrect. If you look at the actual publications for 2003 and later, only a few could qualify as “publishing in the peer-reviewed literature on climate change”. In particular, here is how I would breakdown the 18 things he has listed there on his publication list for 2003-2008:
– Six appear to be atmospheric science works unrelated to climate change (#213, 214, 216, 219-221).
– Three were published in the popular press (#226-228), in particular, the Wall Street Journal or Business Today.
– Three are listed as “in preparation” or “submitted” (of which one seems to be to the popular press and may or may not have some relation to climate change) (#223-225).
– One is a biographical memoir.
That leaves us with five that are at least related to climate change and were published somewhere other than the popular press. One is a chapter in a book on climate change from the Brookings Institution; I don’t know what sort of refereeing they had for it (#222). One is a paper submitted to an economics journal regarding the Stern report (#229). One is an article in the journal “Energy and Environment” not considered a serious journal to interact with one’s scientific colleagues since, among other things, it is received by only a handful of libraries throughout the world) (#230). Two (#215 and 217) are honest-to-goodness papers in journals although both are comments on other papers rather than independent papers in their own right…Still, I am willing to count them.
So, his overall published output over those 6 years has been 2 comments on climate change in refereed journals in the field, and maybe a couple of other papers that you could vaguely count if you really wanted to be generous. And, if you compare that to his output before 2002, I think you will see there is a fairly marked change. Hence my statement that “at least to my knowledge, he seems to have pretty much given up publishing in the peer-reviewed literature on climate change, instead publishing op-eds in the Wall Street Journal and screeds that Smokey likes to link to, and giving testimony to the House of Lords” seems to be a reasonably accurate description, depending on exactly how one interprets my modifier “pretty much”.
VG says:
However, the magnitude of the variations in solar irradiance are very small in the solar cycles…So small that the radiative forcing change is equal to, as I recall, something like 7 years of rise of CO2 at its current rate. The magnitude of the variations over longer periods of time is more uncertain and Leif can fill you in more on that but I think the current thinking is that it is likely on the low side of what had previously been believed.
Simon Evans [06:15:42],
I’m not arguing, and I didn’t ‘rant.’ I’m still just trying to get a straight answer. [But first, you stated that I wrote, “some call it pollution, we call it life”. Since you put it in quotation marks, you are quoting me verbatim. Please point out the time I said that, in case my memory is failing me. Thanx.]
OK, by the numbers:
1) I didn’t ask about what ‘scientists claim.’ I really want to know what you believe. Really. Will an increase in a minor trace gas that is a .00038 part of the atmosphere, to, say, .00048 part of the atmosphere, cause runaway global warming? Take your best shot. Yes or no.
2) Aside from the fact that the Antarctic is significantly cooling, and despite the fact that Arctic sea ice is well within historical norms, you now say that “once we go to a summer ice-free state in the arctic…” Are you stating for a fact that the Arctic will become ice-free? When? And is CO2 your putative cause? If not, then what is? Is it natural, or is it AGW? Enquiring minds want to know.
3) Well, I’ll skip responding to #3, since you’re just stating your opinion. Which you are entitled to, of course.
4) I would also answer your #4 by explaining the difference between a market system and fascism, where a central government directs investment and production, but I prefer to remain on point and get to the central question of AGW: Do you believe that an extremely tiny trace gas change in the composition of the atmosphere over the past century, which left 99.99962 of the atmosphere unchanged, will lead to runaway global warming, melting the ice caps, etc., etc? If so, how do you explain this? Or this?
If you have any doubts about the claims of catastrophic climate change, don’t you think it would be prudent to hold off on the wild spending proposals, until we know just a little more? Because the multi-trillion dollar cost of CO2 “mitigation” is already on the table — and the Davos Economic Summit this week is already discussing a “World Income Tax” to combat global warming. Tax receipts to be distributed through and by the UN, of course.
You seem to be reasonable, Simon Evans. In fact, your views here seem to be moderating. That’s a good thing! There are already plenty of AGW extremists. Your voice is not necessary if you’re competing with James Hansen’s apocalyptic view, he will drown you out with his celebrity status.
Finally — and this can not be repeated often enough — references to the UN/IPCC are references to a group of entirely political appointees, whose agenda is to levy huge world taxes on the U.S. and Western democracies to supposedly combat the fabricated bugaboo of AGW. The IPCC has forfeited credibility from their first assessment report predicting 20 meter rises in the sea level, etc., and every subsequent report has been backing and filling. Elmer Gantry had more credibility.
Joel Shore
Sorry, Joel. That’s wishful thinking on your part.
I have a question about the propriety of Dr. Theon signing off on Dr. Hansen’s budget: Dr. Hansen is actually employed by Columbia and is a contractor for NASA, yes? Dr. Hansen is an academic and academics spend a lot of time chasing grant money. (My sister has several employees who do nothing but write grant proposals for her institute; and Dr. Hansen is a much bigger player in his field than she is in hers.) Does NASA “administer” his grant money? If so did Dr. Theon have the right to deny him his grant money by excluding it from his budget?
This article is making accusations without backing any of them up.
Scientists manipulated data to fit their models – how?
Models omit certain sub grid scale processes – which ones?
Lack transparency- then how do you know what’s been manipulated and omitted?
Smokey (19:20:54) :
I am liking it buddy! I like point 4, Do you believe that an extremely tiny trace gas change in the composition of the atmosphere over the past century, which left 99.99962 of the atmosphere unchanged, will lead to runaway global warming, melting the ice caps, etc., etc?. HAH! No need for further discussion. You give me your “click” links which are entirely unpredictable, sometimes serious, sometimes humorous, or corny and left-field, but pull off an argument like that? Brilliant. You’re a complex dude, entertaining, cynical, skeptical of most things, and really scientifically aware. I just wanted to give you a shout-out. Great stuff. You and I would probably have a blast swilling beers around a campfire (well, at least I would like the beer…)
Joel Shore (19:10:36) :
VG says:
if you turn the sun off
Please, can we stop this recurring nonsense?
Smokey: “…references to the UN/IPCC are references to a group of entirely political appointees, whose agenda is to levy huge world taxes on the U.S. and Western democracies…”
I’m somewhat shaken to hear that, Smokey. For myself, I have tended to view the IPCC pronouncements as cast in stone, or at least on good quality bond paper. But if what you say is true, the UN plans to beggar the Western world.
As a tax-and-spend liberal who lives in the Western world I’m not too unhappy about levying taxes, huge or otherwise, as long as someone else pays the taxes and I can do the spending. But the scenario you present upends this natural order to introduce something quite foreign to my nature.
This is very disturbing news. What can we do? One option would be to raise a fund to prosecute the perpetrators of this fraud. A template exists in the Obama campaign, which raised millions of dollars from quite ordinary people via the internet.
There would be sweet irony in this: using Al Gore’s own invention to smite him to his flabby knees for a well-deserved thrashing.
I’m quite busy at the moment, but you seem to have the makings of an energetic campaigner. I’m sure many WUWT readers would be willing to contribute to your fund. Better than paying taxes to an unrepresentative and corrupt one-world body run by third-world dictators.
Smokey and Simon Evans
I have put up my comments on the queries by Simon on the Co2 thread by Frank Lansner.
TonyB
@Oh bother
Hello Oh Bother, as I understand it (and I’ve just checked his CV) Hansen is Director of GISS, hence a NASA employee. He is also an adjunct professor at Columbia, but that’s only a secondary academic affiliation.
Goddard money comes straight from NASA. John Theon explains in his letter that he was the man inside NASA responsible for allocating Hansen’s resources, so Hansen would have to apply straight to John Theon for his research budget. John Theon explains that he also “had to justify his [Hansen’s] funding, allocate his resources, and evaluate his results”, so he was responsible for justifying Hansen’s work up the line, and checking the results of his work as well.
bob tisdale
RE PDO
THIS IS FROM THE PDO WEB PAGE . I DON’T KNOW WHERE YOUR PERSONAL DEFINITION FOR PDO IS COMING FROM. I STAND BEHIND MY PREVIOUS COMMENTS
The PDO is often quantified by the use of an index, referred to as the PDO Index. The PDO Index is calculated by spatially averaging the monthly sea surface temperature (SST) of the Pacific Ocean north of 20°N. The global average anomaly is then subtracted to account for global warming (Mantua, 2000). Normally only October to March values are used in calculating the PDO index because year-to-year fluctuations are most apparent during the winter months (Mantua, 2001).
When the PDO Index is positive, waters in the north central Pacific Ocean tend to be cool, and waters along the west coast of North America tend to be warm. The opposite is true when the PDO Index is negative (Null, 2002).
The effects of the PDO are most drastic in the Pacific Northwest. In this region, a positive, or warm phase PDO, generally correlates with lower than average rainfall and higher than average air temperatures. Likewise, a negative, or cool phase PDO, correlates with relatively high precipitation rates and low air temperatures (Null, 2002).
The following figure shows how the PDO Index has varied over the past century. The PDO appears to oscillate between warm and cool phases every twenty to thirty years. 1900 to 1924, 1947 to 1976, and 1998 to present correspond to the negative, cool phase. The rest of the time period corresponds to the positive, warm phase.