Via Roger Pielke Sr. climatescience blog:
At the December 2008 NRC meeting “Detection and Attribution of Solar Forcing on Climate” [see] there was extensive criticism by Gavin Schmidt and others on the research of Nicola Scafetta with respect to solar climate forcings. He was not, however, invited to that December meeting.
There is now a new paper that he has published that needs to be refuted or supported by other peer reviewed literature (rather than comments in a closed NRC meeting in which the presentors would not share their powerpoint talks).
The new paper is
Scafetta N., R. C. Willson (2009), ACRIM-gap and TSI trend issue resolved using a surface magnetic flux TSI proxy model, Geophys. Res. Lett., 36, L05701, doi:10.1029/2008GL036307.
The abstract reads
“The ACRIM-gap (1989.5-1991.75) continuity dilemma for satellite TSI observations is resolved by bridging the satellite TSI monitoring gap between ACRIM1 and ACRIM2 results with TSI derived from Krivova et al.’s (2007) proxy model based on variations of the surface distribution of solar magnetic flux. ‘Mixed’ versions of ACRIM and PMOD TSI composites are constructed with their composites’ original values except for the ACRIM gap, where Krivova modeled TSI is used to connect ACRIM1 and ACRIM2 results. Both ‘mixed’ composites demonstrate a significant TSI increase of 0.033%/decade between the solar activity minima of 1986 and 1996, comparable to the 0.037% found in the ACRIM composite. The finding supports the contention of Willson (1997) that the ERBS/ERBE results are flawed by uncorrected degradation during the ACRIM gap and refutes the Nimbus7/ERB ACRIM gap adjustment Fröhlich and Lean (1998) employed in constructing the PMOD.”
A key statement in the conclusion reads
“This finding has evident repercussions for climate change and solar physics. Increasing TSI between 1980 and 2000 could have contributed significantly to global warming during the last three decades [Scafetta and West, 2007, 2008]. Current climate models [Intergovernmental Panel on Climate Change, 2007] have assumed that the TSI did not vary significantly during the last 30 years and have therefore underestimated the solar contribution and overestimated the anthropogenic contribution to global warming.”
Interestingly, TSI has been on a slight downtrend in the past few years as we get closer to solar minimum. The graph below is from the ACRIM project page.
Click for a large image
It remains to be seen if we have hit the minimum yet.
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Leif Svalgaard (20:54:51):
If on the other hand there are other ’sources’ or conditions that drive climate then you can have a varying ‘baseline’, but then solar activity is no longer the major driver, so the discussion is moot.
Dear Leif,
I think the discussion is not irrelevant. Let’s say the solar activity is the major driver of climate, and the other “sources” are modifiers of the climate changes caused by the solar weather.
Wonder what Leif thinks of this (recent published work by W Soon))
“The most recent scientific evidence shows that even small changes in solar radiation have a strong effect on Earth’s temperature and climate. In 2005, I demonstrated a surprisingly strong correlation between solar radiation and temperatures in the Arctic over the past 130 years. Since then, I have demonstrated similar correlations in all the regions surrounding the Arctic, including the US mainland and China.”
“There is no such match between the steady rise in atmospheric CO2 concentration and the often dramatic ups and downs of surface temperatures in and around the Arctic. I recently discovered direct evidence that changes in solar activity have influenced what has been called the “conveyor-belt” circulation of the great Atlantic Ocean currents over the past 240 years. For instance, solar-driven changes in temperature, and in the volume of freshwater output from the Arctic, cause variations in sea surface temperature in the tropical Atlantic 5-20 years later.
These previously undocumented results have been published in the journal Physical Geography. They make it difficult to maintain that changes in solar activity play an insignificant role in climate change, especially over the Arctic.”
Joel Shore (10:13:55)
‘climate sensitivity (2 to 4.5 C) for the doubling of CO2 that the IPCC considers to be likely values.’
So Joel, where’s the observed evidence of the hot spot, warming oceans and increase of heat trapping clouds or, in general, water vapor being a positive feedback to “heat”?
I don’t know what he’ll say, but this looks mighty fishy even to my untrained eye:
Some random number varying between 5 and 20 hardly seems like a “strong correlation.” If it were some fixed number that would be interesting, but I sense voodoo at work…
Why does no one except Leif question the statistical basis for the Scafetta-Wilson paper? We have over 100 comments here, just regurgitating stuff which has already been done th death.
The only interesting thing about this paper is that it was published, and passed review. It seems to have no content in itself.
I find the above-stated idea, that the TSI could have different effects at different times, very intriguing. If an oceanic oscillation was rushing full speed from a warm phase to a cold phase, it makes sense to me that a slight effect from the sun would be less obvious, than the sun’s slight effect would be when the oscillation was hesitating indecisively, in a sort of precarious balance.
I do like things neat and tidy, and was somewhat annoyed when I discovered that the warm phase of the AMO didn’t adhere to a thirty-year schedule like clockwork. However it doesn’t. In fact the AMO is likely impossible to predict, using past statistics. Something external is likely switching the AMO from cold to warm to cold again.
I don’t discount the TSI, though it’s effect may seem weak, for it tends to be a persistent force, and a weak and flabby starfish can open a tough oyster through steady persistence. Also, at the right time in the right place, a little pebble can stop a mighty river, (when the pebble rattles down a slope and starts an avalanche.)
The fact the TSI changes slightly during the sunspot cycle suggests its effect might switch from one way to another, perhaps cancelling itself out, however when a minimum is extended, the admittedly slight effect might become more obvious.
The slight effect that the TSI would have would seemingly be quite different if the minimum began when the AMO was in full flood from cold to warm, than it might be if it was in full flood from warm to cold.
I find this stuff engrossing and intriguing. It involves the study of chaos.
I far prefer attempting to sort out the atmosphere to sorting out my desk and the chaotic system I call “my finances.” However I actually can sort out my desk, (and in fact must, with tax deadlines approaching.) Sorting out the atmosphere is another matter. But it is fun to try, even if it is impossible.
Parse Error: You wrote, “I don’t know what he’ll say, but this looks mighty fishy even to my untrained eye…”
I’d have to agree. The following is a graph of inverted Atlantic Meridional Overturning Circulation (volume) versus NINO3.4 SST anomalies. Though there are divergences, they correlate well enough to illustrate that the North Atlantic AMOC responds without a lag to major changes in “forcings”. One wouldn’t expect a slow-acting variation in TSI to then have a lag.
http://i33.tinypic.com/5cyglz.jpg
The graph is from my post “Atlantic Meridional Overturning Circulation Data”:
http://bobtisdale.blogspot.com/2008/11/atlantic-meridional-overturning.html
North Atlantic SST anomalies are tough to analyze. In order to weed out the impact of TSI, you also have to account for the changes in flow in addition to the usual suspects–ENSO, volcanic eruptions. And of course, the AMOC flow rate is impacted by the AO as well. There are also anomalous events that impact the North Atlantic SSTs. There’s a video that shows a Kelvin wave starting eastward in the Western equatorial Pacific. It gets about 3/4 of the way across the Pacific, then shifts course to the Northeast, crosses Central America, and causes a blossom of elevated SSTs across the North Atlantic up through Britain. It’s visible in the SSH video from the NASA Jet Propulsion Laboratory. You can download it here:
http://sealevel.jpl.nasa.gov/gallery/tiffs/backup/videos/tpj1global.mpeg
Fast forward to May 2001 and keep your eye on the central equatorial Pacific. Around July 2001, you’ll see the Kelvin wave moving east, but it doesn’t go all the way to Ecuador. It heads northeast and scoots across Central America into the North Atlantic. How would you factor that noise out of an analysis of the North Atlantic? It doesn’t show up in NINO3.4 data, but would in North Atlantic SSTs. Too bad that video ends so soon.
I find it interesting that some think the science is settled on the TSI minimum. All current estimates are based on proxy records. Even more interesting is that we wont be able to prove where the TSI floor might be for several hundred years.
The Upcoming grand minimum is just a baby, nothing like the Sporer or Maunder, but we may get a little insight….will Lean regret moving her 2000 TSI baseline?
Also it seems we can have all sorts of random events associated with the Solar dynamo theories, but if we use that logic with our oceans and atmosphere it doesn’t cut it?
Lindsay H,
Thanks for the link to the pdf.
Interesting. One of the “proofs” (the one relating to miscalculating 33C in the absence of a “greenhouse” effect) superficially strengthens the AGW case, perhaps — when considered from a certain slant. On the other hand, the basis for 33C (or any other baseline temperature, trying to exclude “greenhouse”) is certainly called into question to my way of thinking — now I need to learn more.
Leif Svalgaard (20:54:51) :
Pete (19:58:31) :
You are starting your earlier temperature at a lower baseline than your current cycle so the temperature could never be similar to the temperature of the current cycle.
The concept of a baseline is not useful here, because TSI and solar activity in general return to the same level at every single minimum ‘forever’, so the ‘baseline’ is simply that minimum value, provided solar activity was the major driver. If on the other hand there are other ’sources’ or conditions that drive climate then you can have a varying ‘baseline’, but then solar activity is no longer the major driver, so the discussion is moot.
Leif,
I believe there is a “baseline” of sorts in temperature series that can plausibly (but maybe not exclusively) related to solar as a major driver. I’ve displayed these kinds of charts before, but because of their novelty, I don’t think people appreciate or understand what they are looking at. If I can briefly indulge you here, I want to show you two, and make a couple of points about them.
Here’s the first one:
http://s5.tinypic.com/261nb12.jpg
This is global data (HadCRUT3). What you are looking at are monthly rates of change (1st differences) in a smoothed series. But ignore the smoothing. If you can, just visualize what you see as a representation of the amplitudes of a wavelet transform (because I can demonstrate the equivalence). Globally, on decadal and bidecadal time scales, there is an amplitude of ± ~0.0025C. Not a lot, but it is there, it is “statistically significant,” and it is within a range that can be attributable to TSI.
I think there is a lot of “averaging out” of the magnitude of the influence in global data, and it is about an order of magnitude greater in regional data:
http://s5.tinypic.com/20kxc8i.jpg
This is for the “Central Region” of the US. The variation, on decadal and bidecadal time frames, is ± ~0.015C, much greater, but still within a range than can be attributable to TSI.
Now I understand that it takes a lot more than this to demonstrate a causal linkage. What I’ve shown here is a unique and novel way of presenting what has been argued in countless papers: evidence of decadal and bidecadal variations in “climate.” But rather than just present evidence of the frequency, I can quantify the magnitude of these decadal and bidecadal variations. And they seem to be of an order of magnitude that could be attributed to TSI.
Finally, to make clear what I’m saying, and not saying, with reference to this image:
http://s5.tinypic.com/25an3va.jpg
What I understand you to be saying is that variations in TSI cannot account for the ~0.8C increase in global temperatures shown here for the past century and a half.
What I’m saying is that variations in TSI could well explain the variation, or undulations, you see in the blue “smoothed” value of this trend. Basically, my “evidence” doesn’t do much to further the debate over the long secular trend in temperatures, but it does provide a new way of looking at all the spectral evidence that has been claimed for a solar-climate link.
Basil
There is a nice video of a presentation made by Judith Lean (the other solar expert besides Leif) where she goes through the impact of solar variability on temperature.
She pulls out the impact of ocean cycles, GHGs, aerosols, volcanoes, etc and then comes up with a solar cycle influence through the residual of:
+/- 0.1C at the surface,
+/- 0.2C in the middle troposphere; and
+/- 0.4C in the stratosphere (which is something I had not heard before this).
It is also a nice overview of climate change from a middle-of-the-road point of view (and she is a very fast talker so in just a few minutes …)
Leif Svalgaard (21:29:42):
…and he does not show> that the Sun is responsible, but instead assumes that it must be [the “what else” argument]:
Dear Leif,
The correlation iron stained grains (ISG)-TSI has been demonstrated systematically and many researchers from diverse areas use ISG for assessing paleoclimate:
http://www.agu.org/inside/awards/bios/bond_geraldc.html
Bar-Matthews M., Ayalon A., Kaufman A., Wasserburg G. J. (1999) The eastern Mediterranean palaeoclimate as a reflection of regional events: Soreq Cave, Israel. Earth Planet Sci Lett 166:85–95.
On the Medieval Global Warming:
Schilman, B., Bar-Matthews, M., Almogi-Labin, A., Luz, B. (2001) Global climate instability reflected by Eastern Mediterranean marine records during the Late Holocene. Palaeogeography Palaeoclimatology Palaeoecology. 176:157–176.
D. Kaniewski, E. Paulissen, E. Van Campo, M. Al-Maqdissi, J. Bretschneider, and K. Van Lerberghe. Middle East coastal ecosystem response to middle-to-late Holocene abrupt climate changes. 2008. PNAS. Vol. 105. No. 37. Pp. 13941-13946.
There are substantial differences between volcanic iron stained grains and SI iron stained grains.
I think it´s clear that when the Sun switched off, we ended with Maunder and Dalton minimum. So if it heats up more, there should be also visible effect. Btw, does anybody know the reason for MWP, when based on sunspot reconstructions the Sun was not stronger than nowadays?
Nasif Nahle (06:56:14) :
The correlation iron stained grains (ISG)-TSI has been demonstrated systematically and many researchers from diverse areas use ISG for assessing paleoclimate:
http://www.agu.org/inside/awards/bios/bond_geraldc.html
Post the exact paragraph here where they say that ISG is a proxy for TSI specifically. I see all the usual kinds of hand waving about heliomagnetic field, solar radiation, etc, but where does it say: “here we demonstrate that ISG depends on TSI, so many percent change in TSI producers such ans such change in ISG, with sucha nd such an error bar”.?
Bill Illis (05:42:52) :
There is a nice video of a presentation made by Judith Lean (the other solar expert besides Leif) where she goes through the impact of solar variability on temperature.
Her conclusions are expressed in this paper:
Lean J. L., D. H. Rind (2008), How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006, Geophys. Res. Lett., 35, L18701, doi:10.1029/2008GL034864.
and is:
[17] None of the natural processes can account for the overall warming trend in global surface temperatures. In the 100 years from 1905 to 2005, the temperature trends produce by all three natural influences are at least an order of magnitude smaller than the observed surface temperature trend reported by IPCC [2007]. According to this analysis, solar forcing contributed negligible long-term warming in the past 25 years and 10% of the warming in the past 100 years, not 69% as claimed by Scafetta and West [2008] (who assumed larger solar irradiance changes and enhanced climate response on longer time scales).
In the video linked by Bill Illis, I believe Judith Lean mentioned the difference between the HadCRUT and the MSU lower troposphere temperature data. Tough to tell because she was talking so fast. For those who aren’t aware of it, a “chunk” (technical term) of the difference results from the Hadley Center’s switch to NCEP SST data in 1998. The NCEP data was incompatible with Hadley’s former COADS SST data, causing an upward step change in the HADSST data. Discussed here:
http://bobtisdale.blogspot.com/2008/12/step-change-in-hadsst-data-after-199798.html
Yet researchers continue to use the HadCRUT data and try to come up with some other plausible explanation for the difference between it and MSU TLT data. Go figure.
Basil (05:33:00) :
What I’m saying is that variations in TSI could well explain the variation, or undulations, you see in the blue “smoothed” value of this trend.
A 0.1% variation of TSI results in a temperature variation [with no lag] of 0.1/4=0.025% = 288K*0.025/100 = 0.07 degrees, which is about what you see and what Lean also admits [her 10% solar forcing]. And I have no problem with that. I would have a problem if there were NOT such a variation.
Bob Tisdale (08:08:22) :
Yet researchers continue to use the HadCRUT data and try to come up with some other plausible explanation for the difference […] Go figure.
Just as they continue to use the outdated [and worse than useless] Hoyt-Schatten TSI when it fits with their pet theory
Why should a few tenths of a percent of solar radiation difference matter so much? I’m not buying it. Is this sufficient even if we measure in Kelvins? Not going to bother with the math. You justify it. You posted it.
From our article on Amplitude of Solar Irradiance and Global Temperature: Standard Temperature is the temperature and pressure where the equilibrium constant for the auto-ionization of water is 1.0×1014. For the Ambient Standard Temperature (AST) the value is 300.15 K (27 °C).
On the other hand, applying the results from Leif calculation, the outcome is as follows:
* The change of TSI in four years was 0.1%, that is 0.025% /year.
* 0.025% /year means 3.41 W/m^2 per year.
* alpha for TSI = 0.1 °C per (W/m^2) on the surface.
* Consequently, the change of T on the surface is 0.34 K.
I think this simply is not true. Multiply the result by 10 and one will have a more realistic value.
Leif Savalgaard has commented at least eight times on this thread on the necessity of proof rather than an assumption or a claim of correlation for TSI “driving” global temperatures (and climate change). If I understand correctly, if one is going to make such a claim, one must use proper statistical methods; without proper statistics the correlation only fits one’s fantasies, even if it also looks beautiful and compelling on a chart — with a little wiggling. I was brought up a short by Sean Houlihane’s comment: “The only interesting thing about this paper is that it was published, and passed review. It seems to have no content in itself.”
I keep reading about the demand for “a” or “the” DRIVER of climate change, even from many skeptics. Did this overriding mentality begin with the change: 1) from trying to identify true polluters (chemicals, particles, etc.) of the earth’s atmosphere; 2) to tying the guilty verdict to CO2 — for ulterior motives? There seem to be so many climate variables, and no one can predict anything at this time. Don’t these truths suggest that an idea such as “necessary and sufficient conditions” might be a more reasonable approach. Then Leif might have more of us helping him with the notion that, yes, the sun is “necessary” but we have no proof yet that it is “sufficient” in and of itself. What else is involved? (if I am understanding well enough)
I realize that much of the debate is about the way fundamental data is gathered, interpreted, and made public, but the conceptual framework for the data seems to be problemmatic. It seems we love our Sun and linear cause-and-effect arguments. I have similar issues with “greehouse gasses” rather than “radiative effects of earth’s atmosphere” (or something like that). The concepts almost require a blockage or a halt to the thinking process.
Nasif Nahle (09:17:18) :
“* The change of TSI in four years was 0.1%, that is 0.025% /year.
* 0.025% /year means 3.41 W/m^2 per year.
No, 0.34 W/m2 per year. Your number is 10 times too high
“* alpha for TSI = 0.1 °C per (W/m^2) on the surface.
* Consequently, the change of T on the surface is 0.34 K.
I think this simply is not true. Multiply the result by 10 and one will have a more realistic value.
divide by 10
Two other formulae would be (assuming TSI varies by 1 W/m2 over the solar cycle) is:
– using Hansen’s unrealistic 0.75C per W/m2:
1 W/m2 / 4 * 0.75C/W/m2 = 0.1875C change
– or using the more realistic number based on what actually happens on Earth and what is currently used in the climate models including GISS Model E:
1 W/m2 / 4 * 0.3C/W/m2 = 0.075C change
I hope some notice how 0.3C per W/m2 actually works and Hansen’s number never seems to actually be used by Mama Nature.
pyromancer76 (09:33:28):
There seem to be so many climate variables, and no one can predict anything at this time.
There are three streams:
1. Anthropogenic Global Warming (AGW).
2. Natural Global Warming (NGW).
3. Indecipherable Global Warming (UGW).
>DJ,
>Here are some temperature trends for you:
> click1
> click2
> click3
Smokey they are not in the paper. Further the first is a nonsense – trend from a peak of El Nino to peak of La Nina is like a trend from summer to winter.
Second is out of date.
Third is not even temperature.
It’s hard – well actually impossible – to have a science debate about human induced global warming when the the evidence for the sceptics consists of a paper which contains zero information about temperature.
PS Bill Illis your analysis does not include albedo and assumes zero heat capacity. It also ignores the trend in the TSI outside of the minima. What purpose is served by presenting evidence so fatally flawed?