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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I agree Leif…not much use trying to find a connection between a variable that is composed of many variables, as they will often cancel each other out, and a real variable connection can be easily lost in the bulk variable signal
I hereby send you the URL of a dutch astro-fycicus, 85 years old but still active in the field of sun and climate: http://www.cdejager.com/sun-earth-publications/.
No correllations, no models, but pure science.
I didn’t believe in physics until I actually went to one.
Leif says: “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.”
Perhaps you are used to insulting people rather than admitting you do not know either. Sad to be you.
I hope the authors are not assuming that solar signals are coherent with surface temperature signals. The oceans have heat capacity. There is a 33 month time lag between the signal and the response (1/4 or the 11 year cycle). If they are not considering this then the analysis is vacuous.
The trouble with Fourier Analysis is that you need a certain number of samples per cycle of whatever frequencies you want to find. For a continuous sine wave, two samples per cycle are the theoretical minimum. In practice, you need more. That sets a limit on the highest frequencies you can see. Also you need a certain number of cycles in the window you are looking at. That sets a limit on the lowest frequencies you can see. Spectral leakage is almost guaranteed for a signal like the climate. That means you will get lots of bogus frequencies. Other than the fact that it gets warm in the summer and cold in winter (ditto day and night), no other climate signals look much like continuous waveforms.
The bottom line is that naively throwing an FFT at data is a recipe for disaster. A good, practical guide to the topic is The Scientist and Engineer’s Guide to
Digital Signal Processing I like it a lot because it assumes that you might actually want to do some signal analysis, and warns you of the pitfalls.
If you want an article that shows how you might analyze climate data Evidence of a Lunisolar Influence on Decadal and Bidecadal Oscillations In Globally Averaged Temperature Trends. There are lots of references and many good comments.
Slight correction for those people who mentioned solar cycle length. The temperature record correlates with previous solar cycle length not current solar cycle length – where there isn’t a correlation.
With a bit of spreadsheeting anyone can see the relationship. Here is a graph for the CET and HadCRUT v3 since 1854.
Filtering the data and correcting for volcanic eruptions will give a tighter correlation (eg see David Archibald’s website), but even a raw graph like this, done in a couple of hours, shows it.
I find it interesting that Love et al have ignored this well known correlation when they are obviously aware of the work of Dr Friis-Christensen, who they cite.
“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.”
Perhaps I’m biased from just having finished teaching this to kiddy-physics students, but I’m afraid I have to agree. Kepler’s observations (from Brahe’s data) of not only precise correlations but precise correlations with clear geometric rules preceded Newton, and without them could Newton have possibly accomplished what he accomplished? Ditto Galileo’s invention of kinematics pre-dynamics. Without the experiments/observations (Brahe), the systematic data analysis and discovery of structure and correlation in the data, the reduction of parts of that data to a simple mathematical model, Newton COULD NOT HAVE INVENTED the law of gravitation and an associated dynamical principle as the “explanation”.
And yeah, his explanation left a great deal to be desired, such as an explanation for action at a distance. A problem that persists to this day. What DOES cause gravity? Curvature of space-time? Exchange of gravitons? Tugs of invisible fairies? I have no idea, but I do know that GMm/r^2 mostly works, except where it doesn’t or requires modification in equally mysterious (but functional) ways.
The basic point is that from the beginning, AGW enthusiasts have based most of their argument on “It’s getting warmer! CO_2 is increasing! Therefore the latter causes the former.” This truly is absurd. Correlation is not causality, as you (Lief) seem to be implying with your airplane example and of course I agree.
However, often correlation is >>all we have<< until causal models consistent with our general body of knowledge can be unravelled, is it not? And sometimes, you know? Correlation does turn out to be causally linked. Sometimes there is physics that people left out of the model that turns out to be important. Sometimes people make sign errors that don't get caught for years, or write code that turns what should be noise in the data and ignored into dominant hockey-stick-shaped signal. This is a hard problem. Hard enough that we may be stuck being Kepler or Galileo, not Newton, for quite some time. While trying to fend of the religious nuts like Bellarmine who want to burn people at the stake for offending their dogma in the meantime.
After all, the world IS flat and it DOESN'T move. Look out the window!
rgb
Dr. Scafetta
The problem with your hypothesis is that you used data based on the casual visual observations, are not type of data accepted by today’s science. This is in a way should be applicable to the sunspot count, where the errors are by two or more magnitudes smaller.
I managed to dig out an acceptable data – set showing reasonable 60 year periodicity:
I was looking for periodicity in 105 year region, and didn’t pay much attention to the 60 year bit.
http://www.vukcevic.talktalk.net/McC.htm
That is on heliosphere side, on the other side of the equation, I also found 60 year clear periodicity in the climate data sets (not temperatures) but I do not think that annual compilations are long enough to be valid (IMO you need at least 3 full cycles).
http://www.vukcevic.talktalk.net/60y.gif
Nicola Scafetta says:
November 15, 2011 at 1:03 pm
Leif Svalgaard says: November 15, 2011 at 12:23 pm says
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.
Which of your papers are you describing? Or was it not ‘on purpose’? Or are you accusing Love et al. of this. Who are you talking about?
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?
I have no dog in this race. My role is mainly to supply, evaluate, and vet the solar input part and how it changes over time.
what he does is not science?
It stops being science when he overplays his hand.
Science is not just about reading accepted results on textbooks alone.
Sometimes it is adding stuff to those textbooks as I have done in a small way.
Konrad says:
November 15, 2011 at 1:03 pm
I would not totally dismiss such studies.
Neither would I, the paper just shows that existing data does not support such studies. Perhaps with more [and better?] data in future the issues will be resolved, but we are not there yet.
Paul Westhaver says:
November 15, 2011 at 1:04 pm
Where is Mars in all of this. It would be useful to correlate Martian temperatures with terrestrial temperatures. Has this been undertaken?
We don’t have enough data for that. An ice core from one of the polar caps would be a wonderful thing to have for this.
Ed_B says:
November 15, 2011 at 1:20 pm
Perhaps you are used to insulting people rather than admitting you do not know either. Sad to be you.
We could hold on forever on this, but I’m sure that this is not what people are here for. Reading up on this stuff might actually help your understanding. I read up on stuff I don’t understand all the time.
pochas says:
November 15, 2011 at 1:23 pm
There is a 33 month time lag between the signal and the response (1/4 or the 11 year cycle). If they are not considering this then the analysis is vacuous.
As would the multitudes of other studies that are not considering this. One could disagree with your assessment that 33 months is enough to change the heat content of the ocean enough, but that is not the issue here.
Correlation and causation 101
The mighty XKCD
Robert Brown says:
November 15, 2011 at 1:42 pm
“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.”
Perhaps I’m biased from just having finished teaching this to kiddy-physics students, but I’m afraid I have to agree.
Like several other commenters you are missing the point of the interactions between the many inputs to the climate system. To separate those is not possible without the physics. That is the point of the paper [and my comment].
M.A.Vukcevic says:
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.”
Only two remarks. First, I complement you on your clearly demonstrated ability to read my mind. Indeed, I almost didn’t type this reply because I am so certain you already know what I’m thinking.
Second, my intriguing hypothesis actually includes using some “physics” — you know, things like maxwell’s equations, mechanics, stuff like that. It strikes me that there may be an additional source of actual heating that has been neglected so far (as far as I’ve been able to tell) that was once upon a time considered to be a cosmologically important heating process in the early solar system. I do not know, however, if the current orders of magnitude support the hypothesis. It would explain a whole lot of the anomaly (if true/reasonable) without recourse to indirect e.g. feedback modulation or trying to squeeze more energy out of direct insolation than is there to be squeezed.
To be honest, I couldn’t tell what you were demonstrating with your orange, red, and blue curves, or where the polynomial functions you wrote down came from. If you are asserting that you can fit the smoothed data with a nonlinear curve, well, that is hardly a surprise — so can I, hand me a pencil. If the curve has some physics behind it, well, hard to tell, isn’t it?
rgb
I’ve learned a little since checking WUWT regularly. I know a little knowledge can be a dangerous acquisision ha ha. Anyway, I thought that sunspots had to do with determining the happenings in the solar cycle and the solar cycle overall was what has an effect on the climate. And you guys hardly even mentioned CO2. So has co2 finally been thrown out the window as the driver to climate change? And it seems to me like discussing angels on pinheads with all the educated guessing going on. As far as I can see all you guys are discussing theories and bashing each other over guesses. I guess that’s how it works, huh? Gotta get the ego pricked once in a while to keep the juice flowing. Keep it up , I’m enjoying the education and I don’t even have to pay tuition other than a hit to the tip jar once in a while.
As I mentioned at the Santa Fe meeting – comparing solar proxies and global temperature may not be the best thing to do. Since some solar forcings appear to have stronger effects restricted to certain areas… E.g. the UV effect on the climate in N- Europa, GCR over certain part of the ocean etc. etc.. Some people find a better correlation of one look at more local temperature records. I think this need to be look at at in more detail… in a more systematic way
The above is cleverly written and interestingly worded and means what? if nothing at all, when did people begin to write about scientific issues so confusingly as to almost completely hide a point about an issue, I read a lot of science and some of the literature can be compared to trying to understanding my local GP’s hand writing, (which is another mystery for another-day).
I’ve seen and read about some very interesting charts of a correlation of temperature change to sunspot activity cycle length, and there are lots of charts on sunspot number and Solar Activity Proxies are these charts meaningless?
I’m probably reading these charts the wrong way, but it seems to me when there are multiple waves of high solar maximum activity or an exceptionally high solar maximum of activity then usually, there is more energy around on the earth as the suns next cycle begins to ramp up, and it looks as if it is true for the opposite part of the solar cycle in that prolonged low solar activity or waves of exceptionally low solar activity between cycles that would usually allow for less energy around on earth as the next cycle ramps up.
Do CME’s cause cloud cover on the northern hemisphere? I’m 98% convinced that they do or play some part in cloud formation, and if the clouds form or move in an area at night then that would usually cause waves of temperatures to rise and fall, surly these ripples can be worked out and even sequenced! If AGW Climate enthusiasts cant do this, then maybe they should be seeking the expertise (help) of other fields such as physicists, astronomers and engineers, I read somewhere that most anthropogenic global warming sceptics have a good grasp of engineering, physics and astronomy, math and programing so there maybe a self-serving interest to why AGW Climate enthusiasts are all biased to their own special form of science of pseudo-authoritative consensus and exclusion.
M.A.Vukcevic says:
November 15, 2011 at 1:51 pm
I was looking for periodicity in 105 year region, and didn’t pay much attention to the 60 year bit.
the 60-yr peak comes from the 18th century and is not persistent, and is not present during the 19th and 20th centuries [as I have pointed out]. So fails this important test: persistence.
Now, we should discuss the Love et al. paper here, so let’s get back to that.
Robert Brown Said, “It strikes me that there may be an additional source of actual heating that has been neglected so far (as far as I’ve been able to tell) that was once upon a time considered to be a cosmologically important heating process in the early solar system.”
That is interesting. Space does have a temperature and the energy of photons are unique to the temperature to the source.
Ed_B
“That statement is false imo. A hypothesis can be tested by using it to make predictions, and when(if) the predictions are observed as true, then the hypothesis is validated. ”
No. hypothesis are never validated. . Evidence comes in to either confirm the hypothesis or disconfirm the hypothesis. Repeated failed efforts to disconfirm a hypothesis and repeated efforts that support it will over time lead people to stop testing. At this point they refer to the hypothesis as a “law” although it’s tenuous truth status ( all science is contingent) has not changed. What changes is people’s willingness to ‘test’ a ‘known” “law”
Sparks says:
November 15, 2011 at 2:15 pm
Do CME’s cause cloud cover on the northern hemisphere? I’m 98% convinced that they do
The oft assumed theory says that many cosmic rays cause clouds. CMEs screen out cosmic rays, so should result in fewer clouds.
As a child in these matters, it seems to me that any correlation with sunspot numbers, etc. (or Malenkovich-influenced insolation changes) might be with CHANGE in Global temperature rather than actual global temperature (which to my simple mind represent an accumulation of historic heat inputs or losses). Apologies if someone has already made such a comment, and I have failed to understand the terminology.
Nicola.
I read your papers. I looked for the data, you didnt supply it. I asked for the code. No joy.
There is not much else to say since your papers are merely an advertisement. merely words on paper and totally insufficient in the reproducibility department. worse than Mann or Jones ever were.
Willis agrees as well, readers of WUWT.
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.
Well, then, that’s the problem with this analysis. There are lots of different signals/forcings (http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-2-5.html), each with it’s own time history (http://data.giss.nasa.gov/modelforce/), and as the article says, you need to go to the physics and measurements (http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf) to separate them.
However, Anthony’s statement that this “New paper by Love et al suggests no prominent role for solar‐terrestrial interaction in global climate change” doesn’t match up. The only thing the paper is saying is that a “phenomenological correlational analysis” is the wrong tool.
“Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?”
When do we see the follow-up paper about the relgious correlations?
Robert Brown says:
November 15, 2011 at 1:42 pm
…
The basic point is that from the beginning, AGW enthusiasts have based most of their argument on “It’s getting warmer! CO_2 is increasing! Therefore the latter causes the former.” This truly is absurd. Correlation is not causality, as you (Lief) seem to be implying with your airplane example and of course I agree.
—————————–
Not so! The AGW argument is “CO2 causes warming (as per physics from Tyndall and Arrhenius onwards)! CO2 is increasing! It’s getting warmer! Therefore the correlation of the second and third confirm that the first and second are the cause of the third.” Or something like that.