Guest post by Alec Rawls
Technically Dr. Muscheler is asking me to retract the title of my post, “Raimund Muscheler says that a steady high level of forcing can’t cause warming“:
I am sure that you are aware of the fact that the title is wrong. I never said that steady high levels of forcing can’t cause warming.
He most certainly did. Here is the sentence of Muscheler’s that I was paraphrasing (with emphasis added):
Solar activity & cosmic rays were relatively constant (high solar activity, strong shielding and low cosmic rays) in the second part of the 20th century and, therefore, it is unlikely that solar activity (whatever process) was involved in causing the warming since 1970.
This is an unconditional statement: the high solar activity of the second half of the century can’t have caused warming because it was “relatively constant.” If Dr. Muscheler wants a retraction he’s going to have to issue it himself, and that actually seems to be what is going on here.
Raimund now rejects the claim that a steady high level of forcing can’t cause warming. Good. But then on what grounds can he dismiss a solar explanation for late 20th century warming?
His email offers a new rationale. Muscheler thinks the lack of warming from the 40s to the 70s vitiates the solar-warming hypothesis:
My point is rather nicely illustrated in the attached figure [at the top of the post]. It shows the sunspot data and temperature anomalies over the last 160 years (annual data and 11-yr average). It shows the high solar activity I was mentioning.
According to your reasoning one would expect a steady warming since 1950. However, the temperatures were rather constant from 1940 to 1970. Furthermore, the temperature and solar trends are opposite during the last 30 years. So I think one would have to invoke a very strange climate delay effect in order to explain the recent warming with solar forcing.
I would be happy if you could correct the title and add this clarification to your post.
Best wishes,
Raimund
There are a couple of points one can quibble with here:
1) Muscheler again invokes “opposite trends,” as if it is the trend in solar activity, not the level, that would be driving temperature.
2) Those trends have not been “opposite for 30 years.” Solar cycle 22, which ran from 1986-1996, had the same sunspot numbers as cycle 21 but was more intense by pretty much every other measure.
3) Muscheler seems to be asserting that temperature has been rising for the last 30 years when it has been roughly flat for the past 15 years (a fact that presents problems for Muscheler’s preferred CO2-warming theory, but is perfectly compatible with the solar-warming theory, after cycle 23 slowed down and dropped off a cliff).
But set those quibbles aside. What is interesting here is Muscheler’s new argument that if the sun had caused late 20th century warming then the planet should have warmed steadily since 1950.
My reply:
Actually, I would say that warming should have been steady since the 1920’s, but that is only if we are looking at the heat content of the oceans (where almost the entire heat content of the climatosphere resides). Unfortunately, we don’t have good ocean heat content data for this period, while the data we do have–global mean atmospheric surface temperature–is dominated by ocean oscillations.
You suggest that it would take some very strange lags for warming from the 40s to the 70s to not show up until later, but would this actually be strange? Doesn’t it fit with what we KNOW: that the cool 40s-70’s period coincided with a cool-phase of the Pacific Decadal Oscillation?
Ocean oscillations are widely acknowledged to be the dominant short term driver of global temperature
Just look at what the CO2 alarmists say as soon as their predicted warming fails to show up (April 2008):
Parts of North America and Europe may cool naturally over the next decade, as shifting ocean currents temporarily blunt the global-warming effect caused by mankind, Germany’s Leibniz Institute of Marine Sciences said. …
“Those natural climate variations could be stronger than the global-warming trend over the next 10-year period,” Wood said in an interview. “Without knowing that, you might erroneously think there’s no global warming going on.”
The Leibniz study, co-written by Noel Keenlyside, a research scientist at the institute, will be published in the May 1 issue of the journal Nature.
“If we don’t experience warming over the next 10 years, it doesn’t mean that greenhouse-gas warming is not with us,” Keenlyside said in an interview. “There can be natural fluctuations that may mask climate change in the short term.”
Wood and Keenlyside aren’t even talking about the PDO, just the measly AMO. For an historical example where natural fluctuations probably really did “mask climate change in the short term,” the PDO is the place to look.
Here is a comparison of JISAO’s PDO index (red) with the HadCRUT3 temperature record (black):
If ocean oscillations are as powerful a climate driver as the anti-CO2 alarmists claim then this graph suggests a simple story: that cold Pacific surface waters swallowed up a big gulp of warmth from 1940-1970, which the PDO then belched back up during its warm-phase in the 80s and 90s. Without the PDO there might well not have been a 40s-70s temperature dip, making warming over the 20th century much more even.
Is the PDO really this influential, or is it largely coincidence that the PDO was in a cool phase when GMAST dipped a couple of tenths between 1940 and 1970? Without good heat content data it is very hard to gauge but logically there is no upper bound on how powerful an effect ocean oscillations can have. As Jo Nova describes meteorologist William Kininmonth’s “deep cold abyss,” the ocean depths form a great pool of “stored coldness” which is “periodically unleashed on the surface temperatures,” a slumbering dragon that with a flick of its tail can grab away large amounts of surface warmth. Thus we certainly can’t rule out that on time scales of up to decades GMAST really is dominated by ocean oscillations.
The CO2-warming theory needs to invoke ocean oscillations more than the solar theory does
Both have the same difficulty with the 40s-70s dip in temperature. For either theory to work the mid-20th century cooling pretty much has to be explained by ocean oscillations, but the CO2 theory now has to rely on the short-term dominance of ocean oscillations to explain the lack of recent warming as well.
That’s the point of Trenberth’s “missing heat,” right? By his calculations there must be lots of CO2-driven heat accumulating in the oceans. Set aside whether the real problem is with Trenberth’s measurements and calculations, the solar theory has no difficulty explaining why temperatures would be leveling off. With the sun having gone quiet this is the maximum likelihood solar projection (with cooling predicted to follow). It is the special case where GMAST actually tracks ocean heat content. Differences between GMAST and ocean heat are to be expected, but it is the CO2 theory that now needs to invoke that likely divergence from maximum liklihood.
Obviously it is not tenable to reject the ocean oscillation argument when applied to the solar theory but accept in when applied to CO2, but this is what the consensus scientists are effectively doing.
Gavin Schmidt on the asymptotic approach to equilibrium
Dr. Muscheler and I almost got to the ocean oscillations question way back in 2005, but Gavin Schmidt grabbed the hand-off. Raimund had claimed in a RealClimate post that a steady high level of forcing can’t cause warming:
Regardless of any discussion about solar irradiance in past centuries, the sunspot record and neutron monitor data (which can be compared with radionuclide records) show that solar activity has not increased since the 1950s and is therefore unlikely to be able to explain the recent warming.
I objected in the comments that:
What matters is not the trend in solar activity but the level. It does not have to KEEP going up to be a possible cause of warming. It just has to be high, and it has been since the forties.
Presumably you are looking at the modest drop in temperature in the fifties and sixties as inconsistent with a simple solar warming explanation, but it doesn’t have to be simple. Earth has heat sinks that could lead to measured effects being delayed.
Gavin Schmidt’s response was similar to Muscheler’s today, but Schmidt was explicit about what the process of equilibration should look like:
Response: You are correct in that you would expect a lag, however, the response to an increase to a steady level of forcing is a lagged increase in temperature and then a asymptotic relaxation to the eventual equilibrium. This is not what is seen. In fact, the rate of temperature increase is rising, and that is only compatible with a continuing increase in the forcing, i.e. from greenhouse gases. – gavin
Like Muscheler, Schmidt ignores the PDO. It is ocean heat content that should undergo an “asymptotic relaxation to the eventual equilibrium,” but all Schneider has to go by is GMAST, so he is implicity assuming that ocean heat content is faithfully tracked by GMAST, regardless of the fact that this relationship can be profoundly obscured by ocean oscillations.
We know that GMAST underwent a substantial mid-century gyration where 20th century warming actually reversed for a couple of decades before accelerated upwards again but we do NOT know that ocean heat content underwent any such gyration. Schmidt assumes it did but the PDO record suggests that it likely did not, in which case Schmidt’s argument that late-century warming must have been caused by CO2 collapses.
The problem is the hidden nature of these ocean-equilibration assumptions
If Schmidt and Muscheler want to dismiss a solar explanation for late 20th century warming by invoking the highly speculative assumption that GMAST is a good proxy for ocean heat content over with the 20th century, that fine. As long as this assumption is made explicit then others can evaluate it and toss any following conclusions in the trash. The problem is that the consensus scientists are not telling the public their real grounds for dismissing a solar explanation.
The consensus position, re-iterated over and over again, is a simple unqualified statement that because solar activity was not going up over the second half of the 20th century it cannot have caused warming over this period (or is unlikely to have caused warming over this period). I have collected a dozen such statements from scientific papers, news articles, and most recently from the First Order Draft of AR5.
Only when I have pressed these scientists on the irrationality of their claim that a steady high level of forcing can’t cause warming do they start hinting towards the highly speculative arguments about ocean equilibration that are the actual basis for their dismissal of the solar hypothesis. Reliance on such hidden assumptions is not science, so job one is to get these unstated assumptions out in the open where they can properly evaluated. Not surprisingly, unscrutinized assumptions do not stand up well to scrutiny, so job two is knocking ’em down.
The rapid equilibrium assumptions of Lockwood and Solanki, knocked down. The implicit assumption by Muscheler and Schmidt that GMAST should track ocean heat content with no major divergence now knocked down as well. It is a weak argument at best, requiring strong claims about matters of vast uncertainty, wrecking any pretension to have ruled out a solar driver for late 20th century warming.
Until these hidden assumptions are stated I suggest that we all take at face value the positions that these scientists actually assert. When they say that because a high level of forcing was relatively constant it is unlikely to have caused warming, we should say that they think you can’t heat a pot of water by turning the flame to maximum and leaving it there, because that is exactly what they are saying.
Then when they come back with their “what I really meant was,” we can expose their real thinking for the unexamined nonsense it is.
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Don B:
Thankyou for your post addressed to me at October 19, 2012 at 1:21 pm.
To ensure that nobody misses it I copy it here.
Yes, I did misunderstand and, therefore, I did misrepresent you.
I completely and abjectly apologise for my error and hope you will recognise it was a mistake on my part and not a deliberate slight of you. I am truly sorry.
Richard
Leif Svalgaard says: October 19, 2012 at 1:03 pm
…………….
Jean Dickey does not know what she is talking about here. Did you ask her what process she would suggest?
I suppose you do extend the compliment to her coautor:
Dr. Olivier de Viron of the Universite Paris Diderot and Institut de Physique du Globe de Paris.
When I read one of your papers I take it for granted that what you wrote at the time is what you knew at the time, so no need for additional enquiry.
Your own 300 year long sunspot data (as well as those of Wang, Lean, and Sheeley)
http://www.vukcevic.talktalk.net/TMC.htm
also suggest that there is an (for some inconvenient) direct strong link between solar activity and the Earth’s magnetic field change.
I looked at the link to John Nelson-Gammon or whatever his name is. Seems fairly reasonable.
But if only half of the warming is expected rapidly and the rest will take 100,000 years of equilibration with the ocean, why is this never used as the main argument? Why do people always talk about the 3C warming, not 1.5 C or 2 C and not 1C warming? Is this not alarmism?
Leif Svalgaard says:
October 19, 2012 at 12:51 pm
However, if we extend the corrected SSNs back to 1750 it looks like this http://www.leif.org/research/Corrected-Wolf-Sunspot-Numbers.png
Those aren’t sunspot numbers. Those are extrapolations of Leif’s IDV magnetic hypothesis.
Some experts don’t go along with it:
http://www.sciencedirect.com/science/article/pii/S136468260800117X
Does sunspot number calibration by the “magnetic needle” make sense?
K. Mursulaa, , , I. Usoskinb, O. Yakovchouka, 1
Abstract
It has been suggested recently that early sunspot numbers should be re-calibrated and significantly corrected using the observed daily range of the geomagnetic declination (so-called rY values). The suggested “correction” method makes an a priori detrending of the rY series and then extends the linear regression between rY and sunspot numbers established for the last 25 years to earlier times. The suggested “correction” of sunspot numbers by roughly 30% goes far beyond the traditional estimates of observational uncertainties of sunspots. Concentrating here on Zürich sunspot numbers (Rz), we demonstrate that the rY values do not actually imply that the observed Rz values in the 19th century are systematically underestimated. Rather, we find that the Rz numbers are fairly uniform after mid-19th century. The suggested “correction” is largely induced by the detrending of the rY series, which enhances the rY-based sunspot activity in the 19th century relative to later times. We also show that while the annually averaged declinations have a rough relation between sunspots and other related solar parameters, this relation is strongly seasonally dependent and, therefore, not sufficiently accurate or uniform to allow annually averaged rY values to be used as a very reliable proxy of solar activity in early times.
A couple of years ago I wrote this post:
http://tallbloke.wordpress.com/2010/07/21/nailing-the-solar-activity-global-temperature-divergence-lie/
Recently I extended it by combining in AMO and ENSO and a co2 model and successfully reproduced the SST since 1876
http://tallbloke.files.wordpress.com/2012/10/sst-model1.png
As Leif said recently, any solar effect on global temperature would be spread centenially. My integration technique successfully models OHC changes on the centennial scale. Alec Rawls is quite right. Historically high levels of solar forcing sustained over decades are perfectly adequate to explain increasing OHC (and thus surface temperatures all the way to 2003.
“the temperatures were rather constant from 1940 to 1970”
Man made SO2 jumped from 1.5 Pinatubo’s to 6.5 Pinatubo’s from 1940 to 1970.
http://sunshinehours.wordpress.com/2012/09/14/are-we-cooling-the-planet-with-so2/
That would have counteracted much or all of any solar changes.
I have to agree with Doctor Muscheler. He said first of all that it was “unlikely” that this was the case, and secondly he was speaking of whether it had happened, not whether it could happen. He’s objecting to your characterization that he said it couldn’t happen.
No he didn’t say it, he implied it, which is a distinction worth observing.
That’s OK, because they were talking only about a cooling that would affect parts of Europe and North America.
Hi Anthony,
In response to Alec Rawls’ article.
Perhaps it is time to consider a possible relationship between Henrik Svenmark’s cloud-seeding hypothesis and the PDO.
It would appear that periods of relative global warming (e.g., the late-1930s through to the late-1950s and the mid-1970s to mid-1990s) coincided with periods of increased sunspot activity. According to Svensmark, the amount of cloud-seeding is a direct consequence of cosmic ray activity in the lower troposphere, which varies according to the intensity of sunspot activity.
This being the case, a period of higher sunspot activity would likely lead to reduced lower tropospheric cloud cover (due to reduced albedo effect) and temperatures.
Conversely, during periods of lesser sunspot activity (e.g., during much of the 19th Century, the late-1950s to mid-1970s and the last 15 years) albedo would increase – a consequence of more cloud cover over the oceans and continents. This would impact the PDO and, to a lesser extent, the AMO.
Accordingly, the PDO would (generally) be impacted by variances in albedo. This would be manifested in drift to more El Nino events during warmer periods of reduced cloud cover and La Nina events during cooler periods of increased lower tropospheric cloud cover.
Needless, to say, land-based surface temperatures are impacted by other factors, such as upward trends in UHI, ash clouds from volcanic and war activity, persistent contrails and, perhaps, recent geo-engineering efforts.
Leif
excellent detective work on the raw data and all the adjustments.
of course some people would prefer to do science by analogy and boil water rather than crunch numbers. I guess they are more at home in the
kitchen than the observatory
Tisdale once again gets bogged down with the definition of the PDO. Instead of bogging down it is better to accept the PDO is a reliable indicator of the ENSO state which has obvious effects on climate.
The PDO and solar drivers are more than capable of explaining temperature trends of any epoch.
Leif: You are such a hack. I chastise the consensoids for saying that a pot of water can’t be heated by turning the flame to maximum and leaving it there and you pretend that I am asserting this as my position. You have done this, what, three times now?
If you ever fail to be incorrigible I am going to send someone over to your house to see who stole your identity.
Yeah agree with all of this.
I had a long running discussion on John Cook’s skeptical science website on the same thing.
When confronted with temperature lags and the PDO to account for T trends in the late 20th century, they squirm and backtrack. I must say, responses to the simple idea of a time lag from solar forcing were sometimes not reasonable, considered, or rational, although the worst responses were from bloggers with little understanding of the arguments, rather than moderators who were at least partly informed of the details.
A conclusion from one moderator was that even with a time lag from solar activity, equilibrium should have levelled off 20 years ago. (Well, there hasnt been any warming for 15 years), However he used a modelled equilibrium model from Hansen and others to declare that equilibrium since this time was increasing, not increasing, which I think is models all the way down.
Daytime temperatures peak hours after noon, seasonal temperatures peak weeks after the solstice, it is a simple idea to translate this to longer term solar forcing, too simple for many alarmists to even comprehend.
Sorry one sentence of mine above should read:
However he used a modelled equilibrium model from Hansen and others to conclude that equilibrium of the atmosphere (that is heat in, matches heat out) since 20 years ago has been decreasing, due to more CO2 trapping more heat, not stabilising as it should be if solar activity was dominant in the late 20th century but which has since declined; however after checking the papers of Hansen et al, I think their equilibrium calculations are just models all the way down.
nuclear writes:
Muscheler’s statement was not absolute, but it was unconditional. That is, it was not stated as relying on any assumptions about ocean equilibration or anything else. When pressed Muscheler did hint at underlying assumptions. The reference to lack of warming from 1940-1970 suggests that he sees this lack of warming as an indication that the oceans had already equilibrated to the high level of solar forcing, but this conditional was not included in his original statement.
But my paraphrase DID change his less than absolute statement into an absolute statement. Is that what Muscheler is complaining about? Is he complaining because my paraphrase fails to leave room for the possibility that late 20th century warming really was caused by the sun? Clearly not. His clarifications are all to bolster argument for ruling out a solar explanation. That’s why I passed over that point. I was just following Muscheler on that one.
If he had said that I was understating the extent to which he intended to leave room for a solar explanation then obviously I would have been glad to issue a correction on that point. But he did not want to walk back his dismissal of the solar explanation. He wanted to re-argue it and re-affirm it.
Oops. Paragraph 3 of my email should read:
This being the case, a period of higher sunspot activity would likely lead to reduced lower tropospheric cloud cover (due to reduced albedo effect) and generally higher temperatures.
Bob: I’ll look into the PDO and how it is calculated, but the general point remains. Ocean equilibrium cannot beinferred just by looking at GMAST.
What we seem to have here, as in so many other instances, is a host of assumptions piled on an inadequate understanding of processes and relationships, compounded by ideology. It is interesting speculation and food for much discussion but not science in the least. In every instance when one examines the oceans the total inadequacy of the data set is more then profound. I am not saying the data that exists is not good. I am saying it is totally inadequate to do much else the speculate and overly generalize.
Steven Mosher says:
October 19, 2012 at 4:00 pm
Leif
excellent detective work on the raw data and all the adjustments.
of course some people would prefer to do science by analogy and boil water rather than crunch numbers. I guess they are more at home in the
kitchen than the observatory
As a skeptic you should not take this document as fact. There are many areas in this presentation that have contradicting evidence from experts in the field.
Agree with dp and nuclearcannoli. The implication may be there, but misinterpreting “unlikely” as “can’t” is not paraphrasing, and the statement is certainly not “unconditional.”
Otter says:
Leif in 5…. 4… 3… 2…. 1…..
And Tallbloke in T(Leif) + 2SinΘ
Who says you can’t solve this problem with an appropriate lag calc?
Thanks Richard. I was aware that you were backing my position. I just wanted to address the point that your comment raised.
Don B asks the analogous question about CO2: is it correct to say that “there’s nothing in recent global temperatures that disproves the importance of CO2 as an agent for climate change”?
Yes. It is not impossible that ocean heat content is rising in accordance with what the CO2 theory predicts. On the other hand, it is fun to point out that according to the predictions made by the climate models that assume late 20th century warming WAS driven by CO2, their model HAS been falsified. Current temperatures are substantially below the bottom of the range that they predicted as at all likely.
http://clivebest.com/blog/?p=3303
Steven Mosher says:
October 19, 2012 at 4:00 pm
Leif
“excellent detective work on the raw data and all the adjustments.
of course some people would prefer to do science by analogy and boil water rather than crunch numbers. I guess they are more at home in the kitchen than the observatory.”
Well, some of us have to rely on the kitchen. 🙂
Gregory Beasley (Prospect, NSW) says: “Accordingly, the PDO would (generally) be impacted by variances in albedo. This would be manifested in drift to more El Nino events during warmer periods of reduced cloud cover and La Nina events during cooler periods of increased lower tropospheric cloud cover.”
Since the PDO is an aftereffect of ENSO, you’ll need to revise this.
Geoff Sharp says: “Tisdale once again gets bogged down with the definition of the PDO. Instead of bogging down it is better to accept the PDO is a reliable indicator of the ENSO state which has obvious effects on climate.”
And once again, Geoff Sharp expresses his misunderstandings of the subject matter. In addition to ENSO, the PDO is also strongly influenced by the sea level pressure of the North Pacific. And that means it is a poor indicator of the state of ENSO, which is a tropical Pacific (not North Pacific) coupled ocean-atmosphere process. When discussing ENSO–and to quote you, “which has obvious effects on climate”—then it would be best to use an ENSO index.
Have a good day.