Compared to the negative magnitudes seen from 1946 to 1977, our current PDO phase shift magnitude is relatively mild. But that could change. Don J. Easterbrook, a retired professor from the Dept. of Geology, Western Washington University, in Bellingham, WA sends this analysis:

The announcement by NASA’s Jet Propulsion Laboratory that the Pacific Decadal Oscillation (PDO) had shifted to its cool phase (Fig. 1) is right on schedule as predicted by past climate and PDO changes.

Global temperatures peaked in 1998 and have not been exceeded since then. Pacific Ocean temperatures began a cooling phase in 1999 that was briefly interrupted by El Nino and dramatic cooling in 2007-2008 appears to be a continuation of a global cooling trend set up by the PDO cool phase (Fig. 1) as predicted [shown in the figure below].

Thus, we seem to be headed toward several decades of global cooling, rather than the catastrophic global warming predicted by IPCC.

If we are lucky, this PDO will be a short event. 2-4 years. If we are unlucky, and it is the “full Monty” phase switch at 20-30 years as Easterbrook suggests, we may be in for extended cooler times. This may result in some significant extended worldwide effects, notably on agriculture.

UPDATE! Professor Easterbrook adds in comments:

“The projected warming from ~2040 to ~2070 is NOT driven by CO2, it’s merely a continuation of warm/cool cycles over the past 500 years, long before man-made CO2 could have been a factor. We’ve been warming up from the Little Ice Age at rate of about 1 degree or so per century and the 2040-70 projection is simply a continuation of non-AGW cycles.

An interesting question is the similarity between what we are seeing now with sun spots and global temperature and the drop into the Little Ice Age from the Medieval Warm Period. Could we be about to repeat that? Only time will tell–We might see a more pronounced cool period like the 1880 to 1910 cool cycle (when many temp records were set) or a milder cooling like the 1945-1977 cool cycle. In any case, the setting up of the cool phase of the PDO seems to suggest cooler times ahead, not the catastrophic warming predicted by IPCC and Al Gore.”

Post navigation

70 thoughts on “More on the PDO shift cited by NASA”

I think extended cooling from PDO shift in the current situation of political hysteria will be good news. Especially if a weaker sunspot cycle 23 means slightly higher low cloud cover resulting in extra cooling the next decade. If cooling doesn’t stop the CO2 hysteria I can’t figure out what will do that.
We also may learn to not listen to politics and science mixed. Just let’s hope technology and free trade makes development continue, despite cooling.

I don’t believe 2 or 3 decades of a cooling mean catastrophe. The previous 30-year coolings have only been a fraction as strong as the warmings. The future also calls for net warming. PDOs I suspect are just lagged reactions to solar activity. The next couple of years will tell us a lot about what the sun will do (sun’s blank today too).
I’m also convinced agriculture will not suffer from some cooling. Cooling could (hopefully) put an end to this CO2 hysteria, thus allowing the huge added agri-capacity to be shifted from agro-fuels to producing food for folks. Already there’s huge mounting pressure to end the agro-fuel folly.

Notice that the linear trend from ~1904 to ~1943 is ~1.4*/C (which was supposedly mostly natural, BTW) while the trend from ~1965-~2008 is ~1.6*/C. That’s remarkably similar, especially considering they lasted about the same length of time. And similarly, if you take the slope from 1943 to 1965, you get -0.2*/C, while taking a visually similar period from 1877-1904, you get a slope of -.7*/C. And again, the duration is about the same.
The point is that the period until ~1940 has features that are nearly identical in both duration and trend to the period since, yet climatologists all concede that the early period is natural while claiming that the latter period is due to (first) aerosols and (second) AGW. Seeing cyclical positive then negative trends like this with an almost perfect 60yr period makes me wonder why we shouldn’t be assuming there isn’t some underlying sinusoid that’s driving much of the temperature swings. If only there was some feature of the earth’s climate that had a roughly 60yr period. Hmm…
Although the fact that the temperature changes seem to precede the PDO shifts by about a decade makes me wonder which is driving which. But the periodicity is undeniable none the less.

Interesting stuff. The true anomaly here appears to be the very cool conditions from the 1940s to 1970s. Perhaps it will never become that cool again(?). Its funny that aerosols are blamed for the mid-20th centry cooling when it is so clearly evident that the pacific was a large driver.
Also: Easterbrook appears to be an AGW believer.

Looking at Don Easterbrook’s projection, I note that temps appear to rise again from 2040 onwards; surely AGW proponents would say that the cooling is just a blip on the warming trend and that the long-term projection is basically upwards? Perhaps they would say that we should be lowering CO2 emissions anyway in the next couple of decades in order to prepare for the warming later this century?

Yeah, interesting … warm, cool, warm, cool, etc.
Anyone notice that the trend is up? Anyone wonder what is causing this upward trend?
Would appreciate dialogue here on ocean/atmosphere/land couplings – even feedback loops).
Off topic (?) but as for catastrophic predictions by the IPCC … doesn’t that depend on how the world ‘develops’ (e.g. SRES scenarios) over the next 100 years?
Don’t get pedantic, the IPCC “projected” sea level rise 59 cm doesn’t seem as dramatic, or catastrophic, as Hansen, Gore et al, … does it?,

I am not an AGW groupie, but I am perplexed by the easterbrook projection. The cooling forcast for the next 30 years does not go lower than the values graphed for the mid 90s, and then projected values continue their relentless climb until 2100. What is the basis for the higher anomaly from 2040 onward?

how did Easterbrook come to the conclusion that this is the full monty shift? His document does not indicate how he got there.
I do agree with his conclusion—perhaps the this may give the catastrophists pause.

Surely a long deep cooling phase would be a good thing
– and return us to the temps of the mid-20th century
Easterbrook’s graphs show a long-term temperatute rise (with PDO superimposed thereupon)
– what is this due to?
– CO2?REPLY: I don’t wish to speculate, perhaps he’ll join in with comments.

It is often said that El Nino and La Nina are responsible for changes in the earth’s temperature but it seems to me that they are more of a symptom then a cause. What heats or cools them?
If I have the flu I don’t blame me being sick on my fever, I blame my fever on the flu.

Professor Don Easterbrook’s defection from the “consensus” is particularly impressive given the stridency of the AGW crowd here in Washington State and even more so at Western Washington in Bellingham where he taught geology.
Such views are more common among geologists than the media reports. Our national and international organizations long ago became co-opted by the the AGW camp, but many of the members are skeptical.
When geologists of Easterbrook’s stature speak out those of us with more to lose (as in employed by government) are heartened.

Any idea of how the second plot is obtained? Is the PDO superposed on the CO2 warming trends?
If one takes the solar predictions the cooling would be most severe, instead of this hiccup on the way to warming.

Just a quick correction, in the last paragraph you say “Easterling”. I think you might mean “Easterbrook” yes?
Very interesting possibilities. Although I don’t want to see it go into a cooling phase due to the potential crop problems in an already difficult period with food, I really do wonder how some of the AGW proponents would react to such an extended cooling period.REPLY: Fixed, thanks.

I look at that chart and to me, it doesn’t look like it’s a chart showing ocean cooling, just a break from warming to a status quo. I am assuming that this is just thought to be part of the normal cycle and doesn’t include much consideration for the less active solar cycles that have been predicted?

Interestingly, this all seems to tie in directly with the Equatorial Pacific Warm Pool and indirectly with the Svensmark Effect.
Somewhere in the late ’90s, several Australian scientists noted a relationship between Warm Pool anomalies and the PDO. What they didn’t tie in was sunspot activity. And then along came Svensmark. If you look at the overall picture, NOAA’s Metha may have hit it on the head: The Warm Pool is the earth’s thermostat (see http://www.epwp.com). I have several great papers on this somewhere, but only God knows where that is!
Jack Koenig, Editor
The Mysterious Climate Projecthttp://www.climateclinic.com

Bill lllis
I don’t see a switch from La Nina to El Nino over the last three months I see a fadeing of La Nina. What I wonder about is what is happening off the coast of Peru. The anomaly that appeared two weaks ago seems to be expanding. Speculating here, but this could be the lead up to yet another La Nina. If you look at the NOAA site you will notice that the waters off the east coast of Africa are anomalously cool.

Bill Innis,
Like Anthony, I’m cautious about whether this is a temporary cool phase, or a flip to a regime like in the 50’s and 60’s. The PDO has a strong short term cycle of 5-6 years, and we seem to be at the limits of that cycle. If the cooling continues, then that makes it more likely that this is a long term “flip.” It would nice to have some analysis of what is happening to the Aleutian low, and surface winds in the north Pacific, since those are part of what defines the PDO.
As to El Nino/La Nina, you ought to take a look at the current MEI (Multivariate ENSO Index). The last three months don’t show any sign of the La Nina letting up any time soon. Here are two strings of values, representing the last six months (through FEB/MAR):
-1.117 -1.121 -1.121 -.948 -1.34 -1.546
9 9 8 12 4 3
The first row of numbers are the MEI itself. The second row is the rank of the MEI for the indicated month, for 58 years of data. The record high rank (58) was set for months during 1997 and 1998. The record low ranks are scattered, with the values for 1 and 2 in FEB/MAR coming in 1971 and 1974, and 4 and 5 during the 1950’s. This is looking to me like it will go down as one of the strongest La Nina’s on record.
Basil

Bill Illis said: “….The anomaly that appeared two weaks ago seems to be expanding. Speculating here, but this could be the lead up to yet another La Nina.”
There are actually three ENSOs: Warm, Cool, and Neutral. Although it could be shifting to Neutral, I suspect as you do, that it may only be taking a “breather” and will morph back into a full blown ENSO Cool (La Nina).
However, if sunspot activity resumes to any great extent, we may end up with either of the other two ENSOs.
Jack Koenig, Editor
The Mysterious Climate Projecthttp://www.climateclinic.com

The projected warming from ~2040 to ~2070 is NOT driven by CO2, it’s merely a continuation of warm/cool cycles over the past 500 years, long before man-made CO2 could have been a factor. We’ve been warming up from the Little Ice Age at rate of about 1 degree or so per century and the 2040-70 projection is simply a continuation of non-AGW cycles.
An interesting question is the similarity between what we are seeing now with sun spots and global temperature and the drop into the Little Ice Age from the Medieval Warm Period. Could we be about to repeat that? Only time will tell–We might see a more pronounced cool period like the 1880 to 1910 cool cycle (when many temp records were set) or a milder cooling like the 1945-1977 cool cycle. In any case, the setting up of the cool phase of the PDO seems to suggest cooler times ahead, not the catastrophic warming predicted by IPCC and Al Gore.

Esterbrooks chart seems to indicate that, roughly, between the year 2000 and 2100 there will be a .3C temperature increase in global mean temperature.
Yawn! Can I go back to sleep now? Global warming is not worth worrying about anymore.
My ,I hope, future grandchildren would be in their eighties by then. I would assume with the enormous inventiveness of humankind that we would have both a greater understanding of nature, and a substantial technological advancement by then. After all our descendants will stand on our shoulders, as they have done for the last several hundred years and reach out to new horizons, that we could never imagine.

General warming trend over the past 100 years is due to less aerosols in the atmosphere, in my opinion (i.e., the air is cleaner today). Apparently, climate models use the cooling effect of aerosols to help “inflate” the role of CO2 to get the results to match the observed temperature rise (particularly the rise in temperautre between 1990 and the present). If, instead, the role of aerosols has actually decreased (i.e., they are doing less cooling), then the climate modelers would have to shift more of the observed warming from CO2-driven climate change onto to “less aerosols” in the atmosphere. Please see the graph:http://en.wikipedia.org/wiki/Image:Climate_Change_Attribution.png
where aerosols emissions have been assumed to INCREASE over the past century. Given the extensive amount of pollution control equipment installed in N. America and Europe, the demise of the Former Soviet Union, the modernization of China, and less burning of ag waste in general around the world, I do not why people insist that air quality is worse today than 50 or 100 years ago. For example, 30 years ago, Chinese burned coal and ag waste in their homes to stay warm and to cook. Today, modern power plants have replaced this dirty practice. The combination of a more active sun and less aerosols in the atmosphere is the best explanation for higher surface temperatures and cooler stratospheric temperatures since 1990. Assuming the sun isn’t as active as it has been over the last 2 decades, and the air doesn’t get measurably cleaner, I doubt we will see temperatures exceed that of 1998 in a very long time. But, temperature will not go back to the lower temperatures of the early 20th century.

Don Easterbrook said: The projected warming from ~2040 to ~2070 is NOT driven by CO2, it’s merely a continuation of warm/cool cycles over the past 500 years, long before man-made CO2 could have been a factor. We’ve been warming up from the Little Ice Age at rate of about 1 degree or so per century and the 2040-70 projection is simply a continuation of non-AGW cycles.
Don thanks for your great work!
With respect to the last sentence in the above quote, I believe this is exactly what the Pogies (anthropogenics) realized when they started this fearmongering. How can they go wrong with their assertions? All they have to do is ride the wave until the temperature hits about where it was during the MWP!
Jack Koenig, Editor
The Mysterious Climate Projecthttp://www.climateclinic.com

Chris said: “General warming trend over the past 100 years is due to less aerosols in the atmosphere, in my opinion (I.e., the air is cleaner today). :
I think you’re absolutely on target with that… except for China where it seems it’s an “Anything goes” environment.
Chris also said: “Years ago, Chinese burned coal and ag waste in their homes to stay warm and to cook. Today, modern power plants have replaced this dirty practice.
I’d like to see some citations on that one. From what I read in various reports, it’s generally the “same ole, same ole” but with additional pollution from the myriad of coal powered generating plants… plants I might add, that were primarily built to serve industry rather than the peasants.
Jack Koenig, Editor
The Mysterious Climate Projecthttp://www.climateclinic.c

Mr. Easterbrook said:The projected warming from ~2040 to ~2070 is NOT driven by CO2, it’s merely a continuation of warm/cool cycles over the past 500 years, long before man-made CO2 could have been a factor.
Oh I can hear it now:
“Easterbrook isn’t qualified to make this kind of statement. He is not a REAL scientist, not a Climatologist! He doesn’t have the proper training that only WE Climatologists have spent YEARS acquiring to be able to interpret the complexities of the climate correctly. He is only a lowly geologist after all… Big Oil…. blah, blah, blah…”

Just checked the Australian BoM’s ENSO site for today’s update:http://www.bom.gov.au/climate/enso/index.shtml
They conclude with:
“The models indicate a low chance of either a stronger warming to El Niño levels or a re-intensification of La Niña conditions during 2008.”
How meaningless is that for a prediction – we might get an El Niño or we might get another La Niña. I could do as well reading my tealeaves!

I agree that our CO2 emissions will push the temperature up a tick or 2 in the next 100 years. But no one can say what the other factors will do. We have to be patient. The next year or two will tell us what the SUN will do.
If we get suddenly a robust cycle 24, then we’re back to the AGWs running the show. But if cycle 24 continues to elude us, then cooling will most very likely have its day (decades!). The cycles certainly point to cooling.
I’m skeptical of Easterbrook’s projections. I’m sure Mr Easterbrook is skeptical of his own projections too…like any good scientist would be.

“I don’t believe 2 or 3 decades of a cooling mean catastrophe.”
All it takes is one day of cooling to bring catastrophe if that one day results in the loss of the midwestern grain crop due to an unseasonal frost. The loss of a significant portion of the US grain crop would be catastrophic for many people in this world.
It has been suggested that such a climate change was responsible for failed harvests in Europe and the common people being short of grain and when informed that the people had no bread, a certain European leader of the time said “Well, then let them eat cake!”. She lost her head soon after that comment.

Drew and Jack,
I posted this hypothesis over at Atmoz’s site a month ago. In response, Atmoz cited a paper that indicated atmospheric aerosols had decreased over the past decade based on satellite-derived data. On this site, Anthony cited a paper where the author claimed lunar eclipses are brighter today than in anyone’s recent memory. This was supposedly due to a cleaner and clearer atmosphere. Drew, there was no link provided with the paper you recommended. Jack, modern power plants (regardless if they don’t have post-combustion pollution control equipment) are still cleaner today than power plants built 50 years ago. Also, they are cleaner than the alternative: a billion Chinese cooking food over coal-fired stoves. Just because China is emitting more CO2 doesn’t automatically mean that they are emitting more aerosols. This is a perfect example of the lazy thinking that permeates the entire climate modeling community! EVERYONE assumes China is emitting more aerosols. Where’s the proof? If particulate matter have fallen in places like the US, Europe, Eastern Europe/Russia, why not China which has modernized faster than any country in history? Finally, I have not found answers to following questions: How is it that one-time events like volcanic eruptions can send aerosols into the stratosphere, but long-term, steady (albeit lower) emissions of man-made aerosols are assumed only to exist in the troposhere for a few weeks’ duration? Also, why is there no distinguishment between sulfate aerosols (sulfur species bound to water) and solid particulate matter like carbon black and fly ash that are dry and carry an electric charge (which means they are likely be carried higher and further into the atmosphere)? According to Atmoz, an aerosol is an aerosol. I postulate that large volcanic eruptions overwhelm the available moisture in the local troposhere, thus allowing more particles to reach the stratosphere. If so, I would expect some man-made aerosols reaching the stratosphere as well. Are any of these factors considered in climate models? Of course not, that would be too scientific. If one ran the climate models assuming NO cooling due to aerosols, how much CO2-driven climate change has to be pulled back to match temperature trends? In essence, I would bet that the background amount of aerosols (i.e., man-made) assumed in the climate models is much too high. Climate models are deficient in two major areas: the role of the sun and aerosols. Until this is nailed down with a better degree of certainty, the predictive capability of the models are crap.

“It is a popular opinion that the temperature of the winter season, in northern latitudes, has suffered a material change, and become warmer in modern times, than it was in ancient times. This opinion has been adopted and maintained by many writers of reputation… indeed, I know not whether any person, in this age, has ever questioned the fact.”
How little things have changed in 200-plus years!
Source: David Ludlum’s great book “Early American Winters 1604-1820”, page 239.

I admire Easterbrook for presenting hypotheses that are falsifiable. That is the opposite of what NASA Goddard and the IPCC choose to do.
Humans have only been studying climate cycles with modern scientific and computational instruments for a limited number of years. We need a lot more patience and humility from the “climate gods” of the orthodoxy (IPCC).
As others have commented, the PDO is just part of the climate mix. Solar effects are important. Land use and distribution of agriculture, forest, and urban areas are important. Soot and aerosols play a role. Greenhouse gases also play a minor role still being worked out.

Looks like Nature (science mag) is starting to get the picturehttp://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/04/30/eaclimate130.xml
We will start seeing a lot more of these type of articles soon as they (AGW crowd) try to extricate themselves. AGW now delayed for 10-15 years by then of there may be another shift. On the other hand it could just be more nonsense.. its only a “model” once again but this time going against AGW LOL. Poor ol Hansen Schmidt Mann… etc. LOL Basically… global warming has stopped its now official LOL
2008 = year AGW was “stopped” (new wikipedia entry) LOL

Let us not forget our eliptical orbit, the precession of equinoxes (or is it oxi?), our axis tilt and a host of other astronomical variations which we may not know of (positon in the galaxy for one). Each one on it’s own may not have any effect but may accumulate into something that plays a role. 700 years ago the Earth was the center of the Universe, 600 years ago the Earth was flat, 30 years ago the Earth was in danger of an Ice Age. 10 years ago Algore was thought to have a brain. Who knows what we will know tomorrow.

Al Fin
Amen to patience and humility. Remember most of the warmers are only figuratively 20 years old. As a young calling they are naturally robust in their belief that they know the truth.
Moreover they have been propelled to the forefront by the IPCC process far faster than they could have ever believed possible.
They are full of certainty but have yet to learn the pateince and humility that life eventually teaches you.

My latest blog entry (http://digitaldiatribes.wordpress.com/2008/04/29/global-warming-and-the-maligning-of-joy/) describes what I consider to be the “maligning of joy” as it relates to Global Warming. Seriously. It’s reached the point where I notice that half the people around me can’t even enjoy a nice, warm day outside because they are so worried about global catastrophe. Before we will see a reversal in attitude on the AGW issue, we need some major countrywide therapy to correct this damaged psyche and ongoing dysfunction so that people can move on to issues that actually matter. Like feeding their families, for instance.

Rex,
Last year Hadley said AGW will return with a vengence by 2009; now some are putting it off until 2015. This could very well be a short negative PDO. But, all things considered (net cooling since 1998;oceanic cooling since 2005, and a strong La Nina which followed a weak-moderate El Nino) I think people should look at a loss of perhaps 25% of the warming since 1976, maybe more. That is, I would place my bet on a 30 year negative PDO.
Also, I’ve seen some people attempt to coorelate the PDO/ENSO cycles with solar activity. There may very well be a link; however, no one has yet proven other than with ancedotal evidence. The oceans stores such more heat energy, and thier processes and circulations are very complex. Also, long term multidecadal solar cycles (other than the 11 year Schwabe Cycle) only oscillate once every 200 years (Gliessberg Cycle). We are at the tail end of the positive or active Gliessberg Cycle. The ending of the Dalton Minimum in 1810-1820 started the current high solar activity the globe now enjoys. It appears only the Russians seem interested in this area of study. If another solar minimum does begin within the decade, the PDO won’t be the only thing we have to worry about

“The models indicate a low chance of either a stronger warming to El Niño levels or a re-intensification of La Niña conditions during 2008.”
The models referenced by the BoM have been consistently wrong about the current La Nina. They have predicted a weak La Nina which would quickly dissapate.
Similarly, Australia region tropical cyclone models over the same period have also been completely wrong, predicting well above average cyclone activity, when we had the quietest cyclone season in 20 years.
The interesting question is why have the models been so wrong?
The obvious answer is the models don’t take into account the primary climate drivers over the last 12 to 18 months.
However, I’m not optimistic we will see an honest appraisal of the predictive accuracy (or lack thereof) of these models anytime soon. To admit that their predictive accuracy is less than chance would be a serious blow to the credibility of the AGW camp.

As if by magic, a new study is appearing in Nature this week from the Leibniz Institute of Marine Sciences, saying that “on top of the warming trend, there is a long-periodic oscillation that will probably lead to a lower temperature increase than we would expect from the current trend during the next years.” How’s that for timing? I’m surprised the BBC haven’t pounced on this yet.
So… there will be a brief intermission, while we adjust our models…

Chris,
The link to the Ramanathan & G. Carmichael ( 2008 ) paper is:http://www.nature.com/ngeo/journal/v1/n4/full/ngeo156.html
I generally post just citations because I figure that people who do have access to online journals that aren’t open access know how to get to the proper source through whatever system they use. I doubt that Nature Geoscience is open access.

Anthony, thanks for drawing attention to Don’s response as an update.
However, in your original piece, there was a link (not there anymore?) to a statement made by Josh Willis of the JPL, it was the press release as I recall (I copied a snippet):
“The comings and goings of El Niño, La Niña and the Pacific Decadal Oscillation are part of a longer, ongoing change in global climate,” said Josh Willis, a JPL oceanographer and climate scientist. Sea level rise and global warming due to increases in greenhouse gases can be strongly affected by large natural climate phenomenon such as the Pacific Decadal Oscillation and the El Nino-Southern Oscillation. “In fact,” said Willis, “these natural climate phenomena can sometimes hide global warming caused by human activities. Or they can have the opposite effect of accentuating it.”
I can’t help but think the extremists on both sides of the “debate” should just extract their collective heads from their collective rear quarters. Their often unqualified rant does not constructively address the issues; it more than not confuses it. Distortion and misrepresentation of *climate science* research is usually unintended by the layperson. However, some (not all) people deliberately obfuscate and misrepresent the science based on their ideological perspective, regardless of the science.
The next 5-10 years will be very interesting in climate research and I would have liked to have seen more posts/comments on ocean/atmosphere/land couplings and climate sensitivity studies (rather than the usual ad-homs).
In any event, keep up the great work.REPLY: The link you refer to (JPL) is in the previous posting, seen here:http://wattsupwiththat.wordpress.com/2008/04/29/nasa-pdo-flip-to-cool-phase-confirmed-cooler-times-ahead/
here is the JPL announcement with that text:http://www.jpl.nasa.gov/news/news.cfm?release=2008-066

The PDO ended the 70s ice age hysteria in 1977, will the PDO end the current warming hysteria. It’s funny that the computer models neither predicted the decline nor can they predict the 10-15 year interlude. The computer models have been wrong at every twist and turn, and now they say natural variability — which is what has been going on all along.
It’s time to call BS on the computer models and get back to real science.
Anyone heard of GIGO? It’s an age old term for computer models that are not tested by empirical data.

I don`t know whether I am loosing the plot here but I thought Anthony was surveying the US ground stations because he and others believed the temperature measurements from these stations are contaminated with the urban heat island effect. If this proves to be correct then how much actual warming has occurred since the 1970`s when urban development started to take off.
Has the UHI effect taken from the 1970`s to the present now reached saturation, ie Do rural stations have any impact on the overall present day temperature measurements, the UHI effect relies I believe on continuing large rural development.
One study I mention is by Dr. Daniel Boice The study showed minimum temperatures at the San Antonio International Airport (the location of the National Weather Station) are increasing at an average rate of about 0.5 degrees Farenheit per decade relative to the nearby small towns.
Temperature comparisons indicate that San Antonio has an increasing UHI effect.4 In other words, San Antonio is hot, and it’s getting hotter!
There are many other studies that show similar results.

Just curious, but why should a positive PDO cause warming? The same goes for ENSO as well, a higher temperature maybe, but surely a warming TREND wouldn’t be expected just a step-shift, so why would temperature continue to rise due to PDO/ENSO, when they themselves are not then rising? Also, why should a positive PDO cause more warming than a negative PDO causes cooling.
Sorry, I’m just living up to the term “sceptic”.

I’m surprised nobody seems to think the long term trend is due to the gradual thawing of glacial ice. Each year, as five more miles of permafrost is thawed, the Earth’s albedo is lowered, thus allowing for slightly greater warming. However, the long term paleoclimate records also show that what goes up, eventually comes back down. Why is nobody predicting (due to Milankovitch cycles) the eventual sudden decline in global temperatures? What good is there in teaching cyclic theories if they are not going to be put into practice?
Personally, I think the timing of this anomalously long solar minimum is related to the present cooling trend. The Earth’s climate is dynamic, meaning that it needs energy to run. The only meaningful source of energy for Earth’s climate is the Sun (and cosmic rays to some extent). How can we model the long term climate without taking the long term solar activity into account? This comes back to the Milankovitch cycles, but there is obviously something else going on, as well.

Milankovitch cycles have a problem, glaciation between northern and southern hemispheres should onset out of phase by at least several hundred years b/c the equator is a thermodynamic barrier between hemispheres. The expected outcome of Milankovitch would bias to one hemisphere or the other instantiating glaciation before the other, but this is not what happens.
AAMOF, Don Easterbrook points out that the paleo records show NH & SH glaciation both onset concurrently, completely in step with each other.

I don`t know whether I am loosing the plot here but I thought Anthony was surveying the US ground stations because he and others believed the temperature measurements from these stations are contaminated with the urban heat island effect.
Worse. It’s all the rural stations that got et by CRN4 with the MMTS switchover.

Very pleased to see this Easterbrook’s post; Stewart Franks of Newcastle University has been saying similar things for some time; that El Nina/La Nina and ENSO fluctuations are merely manifestations of the longer 40 year IPO climate shifts. The consequence for extrapolated upward temp trends then falls into a hole because of the fallacy of basing such trends on temp base periods which straddle, or don’t comprehend the exogenous parameter; the Quirk and McLean paper on the Pacific Event also focused on this discrepancy.

If we are heading for a cooling phase in the next 30 years, does this means that global warming ultimately stops. Based on Easterbrooks projection, the global average temperatures over the next century still continue to rise. The PDO just appears to play as a negative feedback to global warming– so global warming will occur, right? but just not at such an alarming rate.

Possibly. Or not. Was the underlying rise since 1840 a steady recovery from the LIA or was it due to CO2?
And why were temps flat from 2001-2007? No cycle shifts, but increased CO2 yet no warming. Perhaps the underlying rise is over?

For permission, contact us. See the About>Contact menu under the header.

All rights reserved worldwide.

Some material from contributors may contain additional copyrights of their respective company or organization.

We use cookies to ensure that we give you the best experience on WUWT. If you continue to use this site we will assume that you are happy with it. This notice is required by recently enacted EU GDPR rules, and since WUWT is a globally read website, we need to keep the bureaucrats off our case!
Cookie Policy