Dr. Nicola Scafetta has written an extensive summary of the state of climate science today. He’s done some very extensive analysis of the solar contribution that bears examination. Pay particular attention to this graph from page 49:
WUWT readers may remember him from some previous papers and comments he’s written that have been covered here:
Scafetta: New paper on TSI, surface temperature, and modeling
Scafetta: Benestad and Schmidt’s calculations are “robustly” flawed.
He writes to me with this introduction:
On February 26, 2009 I was invited by the Environmental Protection Agency Office of the Science Advisor (OSA) and National Center for Environmental Economics (NCEE) to present a talk about my research on climate change. I thought that the best way to address this issue was to present an overview of all topics involved about the issue and their interconnections.
So, I prepared a kind of holistic presentation with the title “Climate Change and Its Causes, A Discussion about Some Key Issues”. Then, a colleague from Italy who watched my EPA presentation suggested me to write a paper in Italian and submit it to an Italian science journal which was recently published.
========================
Download the report here (PDF -warning over 10 MB – long download time on slow connections)
This work covers most topics presented by Scafetta at a seminar at the U.S. Environmental Protection Agency, DC USA, February 26, 2009. A video of the seminar is here:
The Italian version of the original paper can be downloaded (with possible journal restrictions) from here
========================
Here is the table of contents, there’s something in this report for everyone:
Climate Change and Its Causes: A Discussion About Some Key Issues
Introduction … 4
The IPCC’s pro-anthropogenic warming bias … 6
The climate sensitivity uncertainty to CO2 increase … 8
The climatic meaning of Mann’s Hockey Stick temperature graph … 10
The climatic meaning of recent paleoclimatic temperature reconstructions … 12
The phenomenological solar signature since 1600 … 14
The ACRIM vs. PMOD satellite total solar irradiance controversy … 16
Problems with the global surface temperature record … 18
A large 60 year cycle in the temperature record … 19
Astronomical origin of the climate oscillations … 22
Conclusion … 26
Bibliography … 27
Appendix…29-54
A: The IPCC’s anthropogenic global warming theory … 29
B: Chemical vs. Ice-Core CO2 atmospheric concentration estimates … 30
C: Milky Way’s spiral arms, Cosmic Rays and the Phanerozoic temperature cycles … 31
D: The Holocene cooling trend and the millennial-scale temperature cycles … 32
E: The last 1000 years of global temperature, solar and ice cover data … 33
F: The solar dynamics fits 5000 years of human history … 34
G: The Medieval Warm Period and the Little Ice Age – A global phenomenon … 35
H: Compatibility between the AGWT climate models and the Hockey Stick … 36
I: The 11-year solar cycle in the global surface temperature record … 37
J: The climate models underestimate the 11-year solar cycle signature … 38
K: The ACRIM-PMOD total solar irradiance satellite composite controversy … 39
L: Willson and Hoyt’s statements about the ACRIM and Nimbus7 TSI published data .. 40
M: Cosmic ray flux, solar activity and low cloud cover positive feedback … 41
N: Possible mechanisms linking cosmic ray flux and cloud cover formation … 42
O: A warming bias in the surface temperature records? … 43
P: A underestimated Urban Heat Island effect? … 44
Q: A 60 year cycle in multisecular climate records … 45
R: A 60 year cycle in solar, geological, climate and fishery records … 46
S: The 11-year solar cycle and the V-E-J planet alignment … 47
T: The 60 and 20 year cycles in the wobbling of the Sun around the CMSS … 48
U: The 60 and 20 year cycles in global surface temperature and in the CMSS … 49
V: A 60 year cycle in multisecular solar records … 50
W: The bi-secular solar cycle: Is a 2010-2050 little ice age imminent? … 51
X: Temperature records do not correlate to CO2 records … 52
Y: The CO2 fingerprint: Climate model predictions and observations disagree … 53
Z: The 2007 IPCC climate model projections. Can we trust them? … 54
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oneuniverse (10:41:06) :
We don’t know the limiting terrestrial factors governing the putative GCR-effected warming or cooling, so I don’t see how you can proceed with that calculation with any confidence.
Hey, I’m not the one claiming this is all figured out and well understood. Shaviv et al. are. I’ll agree that nobody [not even them] knows this and that therefore it is hard to extrapolate our non-knowledge to conditions hundreds of millions of years ago and then turn that around to say that those unknown conditions and factors support the theory purportedly operating today.
Brian G Valentine,
China has a vested interest in the Wests economic suicide via the insane carbon dioxide witch hunt/fraud.
Contrary to the myth that China has a symbiotic relationship with the West by way of trade markets, China relies on the West only for as long as it takes to build up its own domestic consumer base, when the transition is complete then China will happily strangle a weak and reliant West into submission.
China only has to sit back and watch as the West implodes and then China is elevated to super power status by default. The Chinese have been engaged in the art of political machinations for thousands of years, they were experts in the art when we in the West were little more than painted savages.
China plays the long game, they prefer to see an opponent destroy themselves rather than engage in open confrontation.
The Chinese are laughing at our utter moronic stupidity and judging by their gigantic cash reserves and the Wests gigantic and increasing debt burden they are winning the struggle for global dominance.
Either the political classes cannot see the dangers or they dont care or they are willing stooges, however I subscribe to the view that the political classes are more concerned with next weeks front page news and ratings while the Chinese plan for the next hundred years.
The west destroys its own industrial base while building up the industrial base of its competitor, every time someone buys a Chinese product they are directly financing the ground up construction of a blue water fleet that will soon challange the US fleet for dominance of the trade routes and when this happens they become the new boss and when they do they will happily use it to dominate the world, watch the Chinese aquire naval bases.
Clarification: When mixing suggestions about anomalies & plots starting from 0 Kelvin, it was in light humor (hence the smiley).
Nevermind frequencies from the planets — are people convinced there’s nothing cyclical about the moon that has been overlooked?
If so, I want to suggest that this is naive. And if there is so little as one important thing that has been overlooked – and everyone is intimidated into not looking for it: Will it ever be found?
anna v, your comment that you perceive most of the public to have no concept of nonlinearity helps me both understand & better-appreciate your slant, but expounding the virtues of chaos might (perhaps inadvertently) support the channeling of funding to abstract-fantasy modelers who (attempt to) tie us in ever-more elaborate spaghetti that explains nothing — and on that note: good to see mention of rain & clouds & albedo.
As for correlation & causation:
Perhaps it is fine to hammer it repeatedly IF it comes, each time, with a cautionary note about CONFOUNDING. A careful network auditor maps details of roots & branches. An auditor’s job is to find what others have missed or hidden, without being dissuaded by assertions that “there’s nothing down there”. Nuanced statistics & data analysis paradigms differ fundamentally from physics paradigms — and no single contributing field has a monopoly on the multidisciplinary viewing lens …and I do underscore the word nuanced, as I’m not talking about wiggle-matching exercises accompanied by brain-dead interpretations. A map showing dead-end streets need not be interpreted as downplaying arteries — i.e. the branches & roots of a tree are connected to the trunk and it is not necessarily the case that only the trunk should be studied in order to understand the trunk.
Leif Svalgaard (08:11:36) :
We show why the measurement of the full spectrum is difficult, and why it is illusory to retrieve it from its atmospheric effects.
Nobody does that. It is measured in space by observing the Sun.
Dudok de wit et al suggests otherwise
Solar UV emission has a profound impact on the upper terrestrial atmosphere.
Because of instrumental constraints, however, solar proxies often need to be used as
substitutes for the solar spectral variability. Finding proxies that properly reproduce
specific spectral bands or lines is an ongoing problem. Using daily observations from
2003 to 2008 and a multiscale statistical approach, we test the performances of 9
proxies for the UV solar flux. Their relevance is evaluated at different time-scales
and a novel representation allows all quantities to be compared simultaneously.
This representation reveals which proxies are most appropriate for different spectral
bands and for different time scales.
The solar irradiance in wavelengths shortward of 300 nm is a key parameter for the specification of the upper terrestrial atmosphere [7]. Variations are observed on time-scales ranging from seconds to years and can impact radio wave propagation, satellite orbits through increased air-drag but also global Earth climate. Unfortunately, there has been no long-term and continuous measurement of the full solar UV spectrum until Feb. 2002, when the TIMED satellite started operating. Even today, the continuous measurement of solar irradiance with sufficient temporal resolution and radiometric accuracy remains a major instrumental challenge [25]. A important issue is the identification of proper substitutes (i.e. proxies) of the solar UV flux for upper atmospheric modeling
Hence illusory in the past.
Many variables in the Earth’s magnetosphere vary with the solar cycle, so the electrons may just vary along with the rest, so why single those out? And electrons are charged. They can’t easily get to the ozone layer. Precipitating particles don’t get that deep into the atmosphere.
And the effects of charged particles on say Nox are well described eg Crutzens Nobel speech .
Away from equilibrium the effects are pronounced, eg Nicolis and Prigogine
On the other hand, far from a local equilibrium
regime, infinitesimal fluctuations may increase and attain
macroscopic values. In this case the system evolves to a
state of “generalized turbulence”, in which the distinction
between macroscopic averages and fluctuations becomes
meaningless.
The physics (from a lay persons perspective) are pretty amazing.
The Flux (flow rate) of cosmic particles (assuming they hit the Earth) are influenced by solar wind and the Earth’s magnetic field. Solar wind helps to further decelerate the particles and the Earth’s magnetic field helps to deflect them.
The cosmic flux varies due to Earth’s polarity and solar wind varies with the Sun’s activity.
So I guess the question is, so what’s the big deal?
The entire consequence of the cosmic particle barrage appears to do little more then deliver high energy particles to the atmosphere which collide with air molecules, produce “air showers” of high energy protons and neutrons and other daughter particles (sounds scary) which end up charging water vapor and produce lightening which makes nitrogen to feed the plants?
I’m probably missing something obvious like the solar system is speeding into a black hole but I really wouldn’t want to be someone trying to slap a saddle on this mess and claiming energy into our ecosystem is a constant.
I completely agree with both Lief and Anna, the models and science are deeply flawed by the system as a whole seems to be doing just fine within its normal variations.
Re: Basil (Mar 16 08:21),
anna v (06:31:04) :
Are you saying there are no “frequencies” (cycles) in nature, just, and only, delta x’s? So are tides just delta x’s? Diurnal temperature variation? Seasonal climate variation? I mean, I thought the difference between winter and summer had something to do with the earth’s transit around the sun, and that there was a predictable frequency about it. You are telling me that it is just chaos? Or what about Milankovitch cycles?
I am trying to explain the wisdom of current physics that tries to derive descriptions of observations and to predict from minimum principles.
1) One starts with Action, i.e. what the incremental energies are doing in the system during time, described as space time deltas
2) One minimizes Action, and the Lagrangian of the system falls out
3)from the Lagrangian the equations of motion fall out depending on the problem
4) From the solution of the equations come space time functions that may have harmonic solutions.
So, the orbits come under 4, in the order of explanations: the reason there are orbits are because of the sequence. It is not orbits that make the sequence.
Chaos is a metalevel on this: there are many equations of motion on the same variables so the diferential equations are coupled and the solutions are not calculable, different tools are need.
Of course, even cycles have “delta x’s,” so I’m not sure where you are going with this. It seems, from your comment ‘”One should never stop saying that ‘correlation is not causation’” that you are almost implying that correlation is never causation.
No, the deltax;s of the cycles are not in a differential equation, they are a solution to an equation.
I have said before that correlation may be a necessary prerequisite for causation. It is not sufficient. That is what correlations is not causation means. It is not sufficient to see a correlation to establish causality. I say “may” be necessary because in complex and chaotic systems it might not be visible, it might cancel out.
And that would repudiate the scientific endeavor entirely. Science is nothing if not a quest to say “A causes B.”
In physics A has to be much more basic than B. That is the sequence 1,2,3, above.
I do not understand why nature cannot be a bit of both — cycles and dynamical chaos. When Paul said that Tsonis et al hadn’t explained anything, I took him to be calling attention that even if you can predict temperature changes from observed patterns like the PDO, El Nino, AMO, etc., that until you can explain where those patterns come from, you haven’t really explained anything.
See above about chaos.
We used to say “problem number A has been reduced to problem number B” when I was a student.
One never really explains anything, just compacts it to simpler and simpler mathematical formulations that have the advantage to be highly predictive.
Let’s assume that they got it right in explaining how these things can interact to create patterns of temperature change. Is the science of climate done? Are there no more questions to ask? Do we not care what is causing the delta x’s (here PDO, El Nino, etc.)?
As I said PDO etc are not the originating deltas.
Chaos and complexity is way over the delta x’s. It is a meta level that springs out of the ordering 1,2,3,4, the way the fingers in the cornstarch experiment spring out of the basic level viscosity, shaking frequency etc.
No amount of dx-ing would describe the fingers ab initio.
Then we have the issue of Occam’s razor to deal with. Your initial reference to Tsonis was in response to my suggestion that a simple combination of two cycles, one approximately a decade in length, and the other approximately two decades in length, can create a beat wave with amplitude envelopes that vary over multiple decades, similar to how global temperatures have in fact varied during the instrumental period. So now we have two explanations, both leading to a similar prediction. Which is the simpler explanation? I’m still on the fence. But I’m not ruling out a lunisolar influence, just because of Tsonis.
Tsonis had 4 cycles. There is no reason to give up a luni solar influence if the energetics work. I would be in favor of it as the reason for the different cycles. All I am saying is that observing a correlation does not mean causation. If for example a lunar-solar model would be shown to create the currents and air currents, there you are, again if the energies are there.
The necessity of chaos comes in when the complexity rises, i.e. many more interdependent through variables solutions are present in the problem, as is happening in climate, and simple models cannot be predictive.
Leif Svalgaard (08:45:45) :
Basil (08:21:01) :
Do we not care what is causing the delta x’s (here PDO, El Nino, etc.)?
Of course we do, and that is the physics part. But we do not believe that there are cycles out there that cause the deltas. The cycles we observe are the [side-]result of physical forces, not something mythical the physics has to conform to.
More than anything else you’ve ever written, this helps me to better understand your take on cycles.
However, I think it leaves unaddressed the question of whether the physical forces are entirely internal, or in part external. I addressed a question to you about this in my “Basil (03:40:07) :” post, but if you replied directly, I missed it. Certainly, I think we understand the physics of the TSI, and the cyclical “[side-]result” of this physical force. Lunar influences are a little different, in that the cycles are not really a “[side-]result,” but are a direct result of the physics. However you wish to describe these, the point of my ” Basil (03:40:07) :” post was to suggest that with just these two physical forces/cycles/whatever, they could combine to create multidecadal (~60 year) cycles of the kind that Scafetta is attributing to SCMSS.
maksimovich (11:38:39) :
“Nobody does that. It is measured in space by observing the Sun.”
Dudok de wit et al suggests otherwise
Whatever they suggest, it is silly to derive the solar spectrum from its atmospheric effects, when we have perfectly good direct measurements from space.
And the effects of charged particles on say Nox are well described eg Crutzens Nobel speech .
These charged particles are not from the radiation belts.
In this case the system evolves to a
state of “generalized turbulence”, in which the distinction
between macroscopic averages and fluctuations becomes
meaningless.
Has little to do with anything, as space plasma are generally collisionless anyway and we don’t make that distinction in the first place.
Brian G Valentine (11:13:40) :
“Cosmic rays” are (extra) galactic radiation; of wavelengths below what is ordinarily classified as “gamma” rays
No, Brian, cosmic rays are not radiation of any wavelengths but protons.
John from CA (11:43:47) :
The cosmic flux varies due to Earth’s magnetic field and solar wind varies with the Sun’s activity.
So I guess the question is, so what’s the big deal?
There is an important point that people overlook/don’t know about: the Earth’s magnetic field is the major factor controlling cosmic rays, at least ten times as important than the solar wind.
Re: Cassandra King (Mar 16 11:27),
Well, the chinese are a bit off topic, but I agree with your analysis of waiting for us to implode. Goes with their martial arts : use the strength of the opponent to destroy him.
I do not know about world dominance though. They have been rather reluctant in their very long history to govern over “devils”, i.e. people not looking like them. One would call them insular, except they are not an island.
The way we are going our grandchildren will live in interesting times.
Bob Tisdale (19:30:40) :
If the global oceans integrate ENSO, then it would be a dominance of El Nino events. Just so happens El Nino events were dominant during that period:
http://i43.tinypic.com/33agh3c.jpg
Also refer to:
http://bobtisdale.blogspot.com/2009/01/reproducing-global-temperature.html
Oh! Wow! I have some reading to do, thanks for the reply and nice site!
lgl (05:52:03) “Could you make that period 2.1 years 🙂 Then Earth-Mars lineup would be a good candidate. jan93, feb95, mar97 appr. Do you have a longer record?”
See my notes here.
Morlet 2pi QBO Period:
http://www.sfu.ca/~plv/QBO_Period_Morlet_2pi.png
( Morlet 2pi complex wavelet:
http://www.sfu.ca/~plv/WaveletMorlet2pi.PNG )
Data: monthly QBO 1948+ (table):
http://www.esrl.noaa.gov/psd/data/correlation/qbo.data
(Convert table-to-column & vice-versa using Excel’s “offset” function.)
anna v (12:06:22) :
All I am saying is that observing a correlation does not mean causation. If for example a lunar-solar model would be shown to create the currents and air currents, there you are, again if the energies are there.
Basil (12:17:28) :
suggest that with just these two physical forces/cycles/whatever, they could combine to create multidecadal (~60 year) cycles of the kind that Scafetta is attributing to SCMSS.
It all comes down to what anna says: if the energy is there, it can happen, if not, it can’t. So ‘cyclists’ will have to show that the energy is there. That said, there are examples from science where nobody could find the energy in the beginning and yet it was there. E.g. what makes the Sun shine, what makes the sea floor spread, what makes magnetic storms, quasars, dark energy [still uncertain]. But, in general, hitching your theory to unknown forces or energy sources makes it very hard to gain acceptance.
Leif Svalgaard (08:45:45) “The cycles we observe are the [side-]result of physical forces, not something mythical the physics has to conform to.”
Basil (12:17:28) “More than anything else you’ve ever written, this helps me to better understand your take on cycles.”
Indeed.
Basil (03:40:07) “Leif, in your 14 points, I’m not sure how you view lunar influences. Internal or external?”
Yes, let’s get an answer to this.
–
Leif, please check the updated units (on the absolute-scale):
http://www.sfu.ca/~plv/V_Sun_SSB_60a.htm
anna v (12:06:22) (and related…)
FWIW, I find anna’s short “exposition” to be admirably on point in describing the underlying approach and mindset of Physics. I would recommend it to anyone.
Many patterns, cyclic and otherwise, may arise from a “bottom up” analysis of any system, complex or not. Some of these patterns might be observable without the analysis, and if they are very persistent, they may be used by humans in an “ad hoc” manner to help with making decisions and projections, but they are not the cause of anything, as she takes pains to point out. The periodic pattern of day and night was used as a “given” long before anyone had clocks or knew that there was a Solar System, but that is an outcome, not an input, just as (in our current world), umbrellas are often the outcome of rain, but they don’t cause it.
The following link: (here), shows a device called a Parametric Pendulum. It is not a complex system. It is just a pendulum in the form of a ball-on-a-stick, that is “driven” by another oscillator which forces the suspension point of the pendulum to move up and down at a frequency that is at your disposal. By playing with two simple parameters, and setting the initial position and velocity of the pendulum, you can create the most incredible range of behaviours. A great many of them are persistently periodic. On the other hand, small changes in the parameters can lead to effects that are just as “regular” but greatly different in form. Other small changes lead to behaviours that have no apparent periodicity at all. This particular device exhibits “deterministic chaos”, and is easy to describe using very elementary starting equations. Simply observing the device in a particular “mode of behaviour”, however, would never lead someone to the underlying Physics.
/dr.bill
Basil: You ended with, “they could combine to create multidecadal (~60 year) cycles of the kind that Scafetta is attributing to SCMSS.”
The Big question: what ~60-year cycles?
The AMO does not have an ~60-year cycle. It is normally accepted to vary over a 50- to 80-year term, but paleoclimatological data suggests an even wider range:
http://i47.tinypic.com/ekkhuc.png
The PDO does not have a ~60-year cycle. Looking at the ERSST.v3b version because it is longer than the JISAO version, the “cycles” vary from ~30 to ~ 50 years:
http://i41.tinypic.com/104gozo.png
Leif,
Via mobile so briefly :
The Earth temperature correlation found by S&V is with the space GCR flux ( = UB), not the flux at cloud level (unknown <= UB). The relevant CRs are at ~10 GeV (according to Shaviv) and are not strongly affected by the Earth's magnetic field.
re: your main reason to reject the GCR-climate hypothesis:
The 10 GeV CR flux has not been constant in the 20th C. , again according to Shaviv, but iirc decreased 1940-1970's and increased for 2-3 decades after (sorry to be vague, can't remember exact dates).
BTW a contradiction in your logict:
You said earlier that HMF has a very small modulating effect on cloud level flux compared to the Earth's MF, now you're arguing that that flux is constant because (you argue) the HMF has been constant for all the 20thC – the latter argument won't work if the HMF has little effect.
re: dr.bill (16:57:41)
Perhaps I might more accurately have said that looking at the graph of the output would not likely lead to the underlying Physics.
/dr.bill
Correction to my previous comment: “flux is constant” should read “flux has been constant in the 20th C.
Bob Tisdale & Ninderthana, I put in my share of years working as an ecologist, botanist, and forest & soils technician and I have a ton of education in those fields, including enriched study of quaternary paleoecology. From that perspective I would caution you very strongly about the utility of the proxies. It’s generally not nearly the simple matter that basic overviews make it sound to be. Biological nature is extraordinarily complex. I would want years of excruciatingly-detailed, first-hand investigative experience with each species across a wide range of factors before judging what the indices are telling – and I would expect a multivariate interpretation to generally be the best for which one could (reasonably) hope. Also, it’s a rare individual who is adept at soundly interpreting messy factor analyses. The majority of analysts neither go beyond PCA nor perform diagnostics, even though there are usually nonlinearities violating assumptions and mucking up maximum likelihood estimation. A ‘black box’ approach to (mis)interpretation is common (mal)practice.
Bob, this ( http://i41.tinypic.com/104gozo.png ) is not a sensible method of determining periods – but the plot is valuable — just don’t use it to measure frequency! Also, please don’t misunderstand that ALL so-called ‘cycle enthusiasts’ are suggesting “stationary cycles” (aside from the dominant ones like the year & day).
Is your new article up (on so-called “60 year cycles”)? If so, please share the link.
dr.bill (16:57:41) “deterministic chaos”
To quote one of my greatest mentors, an academic statistician with a very good-humored, common-sense, down-to-earth gift for cutting a sensible path through ornately-abstract b*llsh*t:
“Too much of this p-value stuff.”
The issue isn’t lack of awareness of what chaos is, but rather how to curb the untenable mainstream habit of pretending chaos is randomness (“noise”) in statistical inference. Followers are blissfully unaware of their falsely assumed objectivity; the brighter folks easily remain gleeful while deceiving and denying their feigned objectivity.
Another correction to 5.02pm post
Should be “10 GeV and above” for the two occurences of “10 GeV”.
Paul, I’d say that you had a great mentor!
In my experience, very few physicists spend much time dealing with the “null hypothesis”. Whether formally or otherwise, we’re all pretty much Bayesians. We “keep what we know, and build on that”.
/dr.bill
Paul Vaughan (15:12:14) :
Basil (03:40:07) “Leif, in your 14 points, I’m not sure how you view lunar influences. Internal or external?”
Yes, let’s get an answer to this.
That is indeed a tricky one. The Moon helps regulate the Milankovic cycles. The Sun warms on time scales of billions. The internal/external should be seen on a time scale of centuries. Anything that takes much longer to play out is not included [as it is not of immediate concern]. Climate itself is defined on a scale of 30 years.
Leif, please check the updated units (on the absolute-scale):
Thanks, you just forgot to say what the units are. km/s? AU/year? ?
Bob Tisdale (17:00:08) :
The Big question: what ~60-year cycles?
There has to be 60-year cycles because of Jupiter-Saturn… 🙂
oneuniverse (17:02:47) :
The relevant CRs are at ~10 GeV (according to Shaviv) and are not strongly affected by the Earth’s magnetic field.
The flux of 10 Gev cosmic rays is so much lower than the typical GCR. And the solar cycle modulation of the high-energy GCRs is much weaker than of the ordinary GCRs. Svensmark’s original work compared cloud v=cover with cosmic ray intensity at the Climax Station in Colorado. 10 Gev cosmic rays can’t get to Climax which has a cut-off rigidity of 3 Gev.
The 10 GeV CR flux has not been constant in the 20th C.
All indicates are that it has, as the energy spectrum has not changed shape and the lower energies [which are most prone to changes] have not changed. See page 6-8 in
http://www.leif.org/research/Historical%20Solar%20Cycle%20Context.pdf page 8
BTW a contradiction in your logic:
the latter argument won’t work if the HMF has little effect.
Yes, because the Earth’s magnetic field has not changed much and in the wrong direction. It has weakened about 8%, so more cosmic rays should have been observed leading to cooling over the 20th C, except you say that the effective ones are of so high energy that they are not modulated by anything.
dr.bill (20:19:43) :
we’re all pretty much Bayesians. We “keep what we know, and build on that”.
Agree with that. We are loath to accept unknown effects by unknown causes.
Paul Vaughan (18:32:45) :
Bob, this ( http://i41.tinypic.com/104gozo.png ) is not a sensible method of determining periods
Very sensible if a phenomenon is only quasi-periodic. It is not sensible to assume that there is a true periodicity from the outset.