New paper by Love et al suggests no prominent role for solar‐terrestrial interaction in global climate change. I’m providing it here for discussion.
We are not convinced that the combination of sunspot‐number,
geomagnetic‐activity, and global‐temperature data can, with
a purely phenomenological correlational analysis, be used to
identify an anthropogenic affect on climate.
Abstract
Recent studies have led to speculation that solar‐terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross‐correlations between sunspot number, geomagnetic activity, and global surface temperature for the years 1868–2008, solar cycles 11–23. The data contain substantial autocorrelation and non-stationarity, properties that are incompatible with standard measures of cross-correlational significance, but which can be largely removed by averaging over solar cycles and first‐difference detrending. Treated data show an expected statistically significant correlation between sunspot number and geomagnetic activity, Pearson ρ < 10^−4, but correlations between global temperature and sunspot number (geomagnetic activity) are not significant, ρ = 0.9954, (ρ = 0.8171). In other words, straightforward analysis does not support widely‐cited suggestions that these data record a prominent role for solar‐terrestrial interaction in global climate change.
With respect to the sunspot‐number, geomagnetic‐activity, and global‐temperature data, three alternative hypotheses remain difficult to reject: (1) the role of solar‐terrestrial interaction in recent climate change is contained wholly in long‐term trends and not in any shorter‐term secular variation, or, (2) an anthropogenic signal is hiding correlation between solar‐terrestrial variables and global temperature, or, (3) the null hypothesis, recent climate change has not been influenced by solar‐terrestrial interaction.
Citation: Love, J. J., K. Mursula, V. C. Tsai, and D. M. Perkins (2011), Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?, Geophys. Res. Lett., 38, L21703, doi:10.1029/2011GL049380.
Conclusions
One of the merits of using three separate data sets in a correlational analysis is that intercomparisons can be made. After treatment for removal of autocorrelation and nonstationarity through simple averaging and differencing, we find statistically‐significant secular correlation between sunspot number and geomagnetic activity. This is expected,
and it serves as important support for our analysis method. On the other hand, after making the same treatment to the global surface temperature, correlations between temperature and either sunspot number or geomagnetic activity are not significant.
We have not, in this study, considered derived proxy metrics of relevance to climate change, such as reconstructed total‐solar irradiance [e.g., Fröhlich and Lean, 2004] or
interplanetary magnetic field [e.g., Lockwood et al., 1999]. Still, we believe that our methods are general, that they could be used for other data sets, even though our analysis, here, is tightly focused on specific data sets. [15] From analysis of sunspot‐number, geomagneticactivity, and global‐temperature data, three hypotheses remain difficult to reject; we list them.
(1) The role of solarterrestrial interaction in recent climate change is wholly contained in the long‐term trends we removed in order to reduce autocorrelation and nonstationarity. This possibility seems artificial, but we acknowledge that our method requires a nontrivial time‐dependence in the data that is different from a simple trend. Still needed is a method for measuring the significance of correlation between data sets with trends.
(2) An anthropogenic signal is hiding correlation between solar‐terrestrial variables and global temperature. A phenomenological correlational analysis, such as that used here, is not effective for testing hypotheses when the data record a superposition of different signals. Physics is required to separate their sum.
(3) Recent climate change has not been influenced by solar‐terrestrial interaction. If this null hypothesis is to be confidently rejected, it will require data and/or methods that are different from those used here.
Paper: http://www.leif.org/EOS/2011GL049380.pdf
h/t to Dr. Leif Svalgaard
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Ged says:
November 15, 2011 at 11:36 am
“The issue is not whether a given hypothesis is true of false, but has to do with a situation where many different signals are present at the same time. To separate them from each other, physics is required.”
I don’t think that is correct. Separating out contributing signals from a complex waveform is standard practice in many fields, such as NMR, and antenna technology we all use.
This works only when the waves are non-interacting.
Ed_B says:
November 15, 2011 at 11:46 am
I disagree. It seems you are unable to accept that Scafettas work is proving to be true, and are looking for ways to hand wave it away.
The demerit or merit of Scafetta’s papers spring from the papers themselves [and your notion of ‘proof’ seems a bit lax], not from my or anybody else’s critique of them, nor from any sycophants’ applause. The point of the Love et al. paper is that phenomenological correlations won’t work. I may add that they should not be a base for policy decisions. Would you accept a hike of your gasoline tax because Jupiter is in the sign of Aquarius?
Like I said, no one has an explaination for gravity, yet I accept that the mathmatics are proven to be valid.
The mathematics is the explanation. And you lost the point which was separation of many different and interacting signals.
William,
There are plenty of mechanisms without having to resort of Stieging new ones. Changes in wind velocity at the ocean surface improve conductive heat loss. The Solar UV change both reduces Ozone production and reduces short wave absorption below 10 meters. In conjunction with the UV change greater than expected, the near infrared change was a little bit smaller surprise, but interesting. Why, a change in the ratio of the atmospheric absorption and the deeper ocean absorption has a greater cooling impact than either by itself. So solar variation doesn’t have the butt to warm much, but it has nearly twice the capacity to cool. Timing though is everything. The ocean tends to buffer shorter time period solar variation. A longer minimum should allow sufficient cooling to be noticeable. We haven’t been through an extended minimum, so we don’t know if or how much it may impact. One thing though is obvious to me, global temperature averages for only a hundred years are not enough to draw conclusions.
Yeah, or like N. Scafetta’s papers. Speaking of which, we should have lunch sometime, Nicola (since we are probably a few hundred meters apart as I’m typing this, if you’re in your office:-). I have an intriguing alternative hypothesis that may or may not be able to explain why the sun’s activity appears to be significant predictor of multicentury heating and cooling trends; one of these days I’ll sit down to work out the numbers to see if it works…
rgb
I always thought that the clear correlation was not between temperature and sunspot number, but temperature and sunspot cycle length.
And dIdn’t Richard Tol go ballistic last week over a paper for comparing trends using “detrended” data?
I said: no one has an explaination for gravity, yet I accept that the mathmatics are proven to be valid.
Leif says:
The mathematics is the explanation. And you lost the point which was separation of many different and interacting signals.
Say what?? Please let know where I can find the physics behind gravity. We all accept that it exists, and that the mathmatics describe it, but how is the attraction between two bodies carried out? (invisible pieces of string? Sub atomic particles pulling with ??).
Nicola Scafetta says:
November 15, 2011 at 12:05 pm
Time series analysis and data mining are serious disciplines in all scientific fields. That paper trivializes the issue.
No, just advocates using proper techniques, good data, and valid physics.
my models are tested on forecasting capabilities backward and forward for decades and up to centuries.
Wow, successful climate predictions centuries ahead. There are also people on this blog who claim they can predict the climate in Timbuktu [‘anywhere’ is the exact claim] in a given month a century from now. They, too, consider their work to be ‘scientific research’. Are you better than they?
interpreting climate change?
The climate changes all the time for many reasons. Beware of prophets pretending to know the truth. Climate research may be having a hard time right now [for various well-known reasons] and that opens the door for pseudo-science and ill-founded speculation labeled as ‘scientific research’. Now, you have in the past advocated having an ‘open mind’. Here are some open-minders for you: http://tamino.wordpress.com/
Well what is left if you take out the long term trend of global CO2 atmospheric abundance, and global surface Temperature, and then look for secular correlations between the noise that remains.
Seems to me that “detrending” or “differencing”, amount to taking derivatives of a sort, and that should lead to an increase in the noise level.
It is amazing to me, that the sun has absolutely no role ion the earth’s climate. So why not subtract out the mean TSI and then do secular correlations on the residue.
Maybe if the models showed SOME SORT of feedback to the original “forcing” namely the TSI, particularly in the case of cloud cover variations, somebody might actually find some small solar influence on earth climate.
Leif says:”Wow, successful climate predictions centuries ahead. There are also people on this blog who claim they can predict the climate in Timbuktu [‘anywhere’ is the exact claim] in a given month a century from now. They, too, consider their work to be ‘scientific research’. Are you better than they?”
I can’t believe what I am reading on WUWT today. First Leif sounded like he defends M Mann’s methods, and now he slags Scafetta with troll like comments(and refers to Tamino??? yikes).
Is this the real Leif or has someone stolen his name?
Leif Svalgaard
November 15, 2011 at 11:00 am
A phenomenological correlational analysis, such as that used here, is not effective for testing hypotheses when the data record a superposition of different signals. Physics is required to separate their sum.
I think this is an important assertion that many commenters here should heed.
###
Most truely, olong with the other caveats.
Removal of autocorrelations can be tricky buisness.
Ed_B says:
November 15, 2011 at 12:21 pm
but how is the attraction between two bodies carried out? (invisible pieces of string? Sub atomic particles pulling with ??).
Although OT, suffice it to note that there is no ‘attraction’ between two bodies. Imagine two airplanes flying straight on from different points on the equator towards the North pole. A naive observer would see the airplanes as if attracted to each other until they collide at the pole. Don’t hijack the blog any further for your education about gravity.
Robert Brown says:
I have an intriguing alternative hypothesis that may or may not be able to explain why the sun’s activity appears to be significant predictor of multicentury heating and cooling trends; one of these days I’ll sit down to work out the numbers to see if it works…
I have done it already, and numbers do work
http://www.vukcevic.talktalk.net/CET-NV.htm
compare orange, red and dark blue curves.
George E. Smith; says:
November 15, 2011 at 12:28 pm
somebody might actually find some small solar influence on earth climate.
There is, there is, to a tune of less that 0.1 degrees. The issue is whether there is a major influence, and the analysis finds that there is no significant evidence in the data: “we find statistically‐significant secular correlation between sunspot number and geomagnetic activity. This is expected, and it serves as important support for our analysis method. On the other hand, after making the same treatment to the global surface temperature, correlations between temperature and either sunspot number or geomagnetic activity are not significant”.
Leif Svalgaard has got it right. We are dealing with a series of interconnected hypothesis i.e. not unlike the multiple working hypothesis we are so fond of in geology. We geologists use this method due to two major and a host of minor factors. We never have all the data and we can never see the whole picture in its three dimensional existence. We these authors and many of us too, from time to time, are trying to do is examine a modeled resulting collection by looking at some empirical data that is interpenetrated with inadequate models. This is further complicated by the need to compare dynamic models and interpretative results with point source static empirical data resulting from some only partly understood dynamic process.
To put is short a unified numerical value, average annual global temperature, is insufficient to understand let alone comprehend what any set of dynamic processes or up to let alone how they influence or interact.
William says:
…………………
William may be talking sense.
If temperature natural variability linked to the geomagnetic activity was a living thing, there is an indicator which would suggest that its DNA was damaged in 1970s-90s.
I’m significantly under-qualified to understand the statistics in use here, but I have two questions.
If you have to understand the physics in order to separate sums of contributions, then haven’t you already solved the problem? It strikes me that the entire climate debate centres on how much various inputs contribute to the temperature record. If you understand the physics – ALL the physics – then why do you need to look for correlations?
Does the paper in question factor in any time lag (sorry, I don’t know a more succinct phrase) between inputs and measurable outputs? e.g. Imagine if, when the sunspot count shoots up, surface temperatures always follow upwards but 321 months later. Would the paper’s analysis method detect a correlation?
Ed_B says:
November 15, 2011 at 12:31 pm
First Leif sounded like he defends M Mann’s methods
Ah, that shows your bias. What has anything I said hinted at that?
and now he slags Scafetta with troll like comments
Anybody who claims to successfully predict climate centuries on and past and pretends it is science, deserves this. You disagree with that?
Is this the real Leif or has someone stolen his name
“you know the lion by his claw”.
Leif says: “Don’t hijack the blog any further for your education about gravity.”
I simply do not accept your assertion that phenomenological correlational analysis must be rejected as evidence of sun/planetary influences upon the earths climate, without first having the physics fully explained.
As for gravity, it is my example. No one has explained how gravity works, and your little illustration does not do it for me. Thus I am becoming very skeptical of what you say about Scafettas work.
@Leif,
“This works only when the waves are non-interacting.”
That’s a very true point.
Leif; If you have a sine curve, and a cosine curve, with the same amplitude.
What would the correlation be? Could one of them cause the other?
Leif Svalgaard says: November 15, 2011 at 12:23 pm says
“No, just advocates using proper techniques, good data, and valid physics.”
Let me know if I understood well your reasoning. One writes a paper using by purpose improper techniques, improper data and no physics at all, and conclude that that is not the way to study climate changes. Is that a great scientific/phylosophical discovery, Leif? What does that paper adds to the science, Leif? Disprove something? No, it doesn’t because nobody uses the same extremely naive methodologies, but you perhaps. Proves something new or propose new revolutionary thecniques? nope! Everybody understands that there is the need to look for “proper techniques, good data, and valid physics”. That is what “scientific research” is all about.
About the other points, Leif, read my papers better. Some tests for forecasting capabilities (within certain limits, of course) have been made. The future will tell, and the models can be improved, of course.
Again, I invite you to tell us your interpretation of climate change. Is “The climate changes all the time for many reasons” all what you know or are able to do? Does that means that people should not study the issue because you have no clue about how to try to address it? Should that mean that if somebody does not come out with a “full” and “complete” theory of climate change, what he does is not science?
See, Leif, scientific research is a dynamic and always evolving discipline, Science is not just about reading accepted results on textbooks alone.
While I would agree with Leif and the authors that studies such as this that seek to identify correlation without a proposed underlying physical mechanism may not achieve much with noisy data, I would not totally dismiss such studies.
Where I would dismiss such studies is if they have been conducted using data collected post 1980 and have been adjusted post 1980 or reconstructions created post 1980. Sadly little relating to climate can be taken on trust past this date. While I am sure much quality work with surface temperatures and solar data has occurred after 1980, the difficulty of sorting the wheat from the chaff is too great. Scientists working on solar climate connections need to acknowledge the lack of trust that has developed. Using data sets published pre 1980 is an easy way around this problem, especially as the 1950 to 1980 period of increased CO2 emissions is covered.
Leif,
Where is Mars in all of this. It would be useful to correlate Martian temperatures with terrestrial temperatures. Has this been undertaken?
Ed_B says:
November 15, 2011 at 12:47 pm
Leif says: “Don’t hijack the blog any further for your education about gravity.”
I simply do not accept your assertion that phenomenological correlational analysis must be rejected as evidence of sun/planetary influences upon the earths climate, without first having the physics fully explained.
The paper shows that there is no statistically significant evidence for this in the data we have. That is all. If there is a real connection, as between sunspot and geomagnetic activity, then phenomenological correlational analysis might be a guide to the physics, as it was, because the signal is large enough, although it is still only when we understand the physics that we can be sure [as we are now, because we know the physical causes].
As for gravity, it is my example. No one has explained how gravity works, and your little illustration does not do it for me.
Perhaps more study of this will help you.
Thus I am becoming very skeptical of what you say about Scafettas work.
Your lack of understanding might well drive you such skepticism. Such is life.
Leif:
Are secular correlations between atmospheric carbon dioxide and global temperature statistically significant?
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“that its DNA was damaged in 1970s-90s.” I thought was due to Peyote? 🙂
Dennis Nickols. That brings us around to small changes and Chaos theory, which Tsonis has had some marginal success. My biggest issue is that from a thermodynamic perspective, the multiple thermodynamic layers with varying time constants are not something that can be well understood using a TOA radiant perspective. Chandler in 1934 seems to have had a better grasp on things.
To put things in perspective, a 1 degree change in surface temperature would change the TOA emissivity from ~0.609 to ~0.602. You can follow the change in the emissivity down through the atmosphere and see that the temperature of the effective radiant layer of the average change has a major impact on the effect at the surface. In the Antarctic, the temperature of the effective radiant layer is never above ~-50C and there would be no appreciable water vapor feedback. It is pretty obvious that was not considered in the models and that the Antarctic is not impressed with the model projections. Conversely, the Arctic has water vapor feedback. So attempting to compare global average temperature time series is a bit of an exercise in futility.
I personally think it is time for a do over, scientific Mulligan if you will, from a more solid thermodynamic perspective.