I’ve trying to avoid discussing the favorite topic of all skeptic blogs. You know what I mean: The all powerful sun whose dimming may have caused Kristen Byrnes to Ponder the Maunder and a frequent commenter at Tamino’s to post comments like:
Eli Rabett // April 5, 2008 at 11:59 pm
What part of there are no 11 or 22 year cycles in the global temperature record don’t folks understand?
Well, Eli, I don’t know what part folks don’t understand.
Nevertheless, John V, who like me, believes AGW is the correct explanation for recent warming, pointed out that there are many who believe solar cycles do have a noticeable effect on the GMST. Moreover, tucked away in Chapter 9 of the AR4, is a rather brief statement suggesting that there may be a 0.1C peak to trough variability in temperature associated with the 11 year solar cycle. (Quote and link here). Chapter 10 describing the actual projections suggests the IPCC mostly omits solar forcing from the SRES. Then, on top of that, JohnV suggested that as it is a known fact that 2001 was near the peak of the solar cycle, and we are now somewhat near the bottom, this could explain the falsification.
Now, despite my aversion to stepping into the arguments about the sun’s impact of the climate, I do have a policy of considering any specifically identified cycle, with a conceret estimate for it’s strength, that might redeem the IPCC projections. (Sorry, but I can’t look at non-specific suggestions. 🙁 )
Since JohnV suggested one, I confirmed the IPCC AR4 does, indeed, mention the possibility that solar cycles matter and with quite a bit of moaning and wailing, I grudgingly agreed to consider the solar cycle. (JohnV will confirm my grudging behavior. I was much more positive about ENSO, because those advocating AGW always discuss ENSO. In contrast, mostly spectics or denialists seem to mention the solar cycle.)
The results? If we assume the 11 year solar cycle imposes a perfectly sinusoidal influence on the Global Mean Surface Temperature, an amplitude of 0.05C, and with a peak centered on Jan 2008, then the IPCC results no longer falsify under this assumption.
Mind you, the central tendency of the measured trend is only 0.8C/ century, which is quite a bit lower than 2C/century, but given the range is -1.4 C/century to 3 C/century, so 2 C/century drops in line.
Here is the graph, with uncertainty intervals. The brown line associated with 2C/century falls between the two fuzzy orange lines. (Note that 0C/century also falls inside the fuzzy orange lines.)
Answers to Obvious Questions
- Did I do anything really fancy? No. This is quick and dirty. You can believe it if you like, or not. With luck, we’ll get discussion and people will dredge up references about the solar cycle and its influence on global mean surface temperatures so I won’t have to! 🙂
- Why 11 years? This is the periods “everyone” pretty much believes is associated with solar cycles. “Everyone” includes NASA GISS.
- Why an amplitude of 0.05C? Chapter 8 or the technical summary of the AR4 suggests a peak-to-trough change of 0.1C (i.e. 2 * 0.05C) is suggested for the 11 year solar cycle.
- Why set the peak of the effect at Jan 2001? This is a combination of the known time of the peak and cherry picking. The peak in the total solar irradiance may be earlier. However, based on phenomenological arguments, there could be a lag of up to 90 degrees in the response. (All things being equal, longer lags will generally be associated with in smaller measureable responses.) I picked the peak to corresponds to a time that improved the linear fit from 1979- now as best as possible. (For what it’s worth 0.05C also improves the fit more than the Camp and Tung suggestion of roughly 0.1C for the solar effect.)
- What do climate models say about the effect of solar variations on GMST? I don’t know.
Steve mosher suggested we examine the data from NASA GISS MODEL E. Evidently, we can examine the averaged results of 5 ensembles. John V downloaded the data, ran an FFT and the model seems to indicate the effect of the 11 year solar forcing is negligible. FFT should reveal strongly cyclic data, particularly in an ensemble average where weather noise is reduced. However, Steve, John and I aren’t entirely positive we are interpreting the NASA resource properly.
- Does this mean 2C/century is confirmed? No. There are two reasons for this.
First, even if you embrace the idea that solar cycles have a measurable effect on the GMST, and the recent flat trend is due to the dip into the bottom of the solar cycle, the 2C/centruy is not “confirmed”. It is only “not falsified”. This is because the “type 2” (‘Beta’ or β ) error for this test relative to 0C/century is 49%. That means that even if 0 C/century is correct, there is only a 49% chance of “falsifying” 2C/century. The range obtained using the simple minded solar model is -1.4C/century to 3C/century.
In contrast, if the entire idea of the solar cycle having a discernible effect on GMST makes your eyes roll, the 2C/century should, in your mind, falsified by the current data with no specific culprit identified. There is still the PDO or AMO, and if someone wants to suggest literature explaining the probable magnitude of their influence, I’m always game to look.
- Do I, Lucia, believe this is “the” explanation for the post 2001 flat trend? Beats me! Will mainstream climatologists say “Oh yeah, the solar cycle is what I personally meant when we alluded vaguely to hypothetical, unnamed cycles or waiting a long time?” Beats me!
But the solar cycle does happen to start at the right time, and published estimates of the strength of the 11 year cycle are of the correct magnitude.
I am of the opinion that if climatologists believe the fairly regular, fairly predictable 11 year solar cycle really has an 0.1 C effect, they should be incorporating this effect into their projections and discussing its probable magnitude in very explicit terms and in discuss it in prominent places in documents written for public dissemination.
For now: I’ll be carrying the “solar correction”, along with a “without solar” comparison forward. As we move into the future, the sun’s intensity is expected to increase, and we’ll see whether warming tracks the expected intensity rebound in real time.
Future work
Some will note I didn’t fold in ENSO.
ENSO explains a lot of the variability, and so adding it explicitly tends to tighten the uncertainty intervals, and potentially reduce β error. However, every time I start getting back to trying to figure out how to deal with that better, someone suggests something else that might be useful to look at sooner. (This can be real work dealing with cyanide canisters or the question of the solar connection.)
So, I am planning to figure out how to incorporate ENSO in some not too idiotic way next month. As I said, I’ll carry both “solar corrected” and “not solar corrected” forward. That way, we can all see whether or not the solar correction ends up tracking temperatures as the solar intensity turns up. (Given the prominence of this in climate-blog-wars, people might be interested anyway.)
But meanwhile: If you believe the sun matters, the IPCC projections may yet redeem themselves. (Though you can wonder why the panel doesn’t include this effect in their projections. Sorry, but the fact that it averages out doesn’t cut it with me.) If you believe there is no 11 year solar effect, then they projections aren’t looking good.
Concrete suggestions invited; (the right to bitch and moan while considering them reserved.)
I’m impressed that you wrote this up.
I was beginning to doubt your neutrality but you have been redeemed. 🙂
(Let the flames directed at my neutrality begin).
One question about your answer to obvious question #3:
If IPCC says 0.1C peak-to-peak, and the trend from Jan2001 to Jan2008 is from peak-to-peak, why use only 0.05C?
Hhnmmm I think it’s peak to trough… I have the quote:
The 0.05 C is center to peak. So, it goes -0.05C at the bottom to +0.05C at the top, which is 0.1C peak to trough. That’s the way I interpreted what is actually shown in a tiny little graph in “H Gleisner, P Thejll – Geophys. Res. Lett, 2003 – dmi.dk” which is cited in Chapter 8, of the AR4 and available in PDF. I considered that paper sort of “enough” to justify where the 0.1C might come from.
Let me go fix that if I wrote peak-to-peak!
Also, since we have that Camp&Tung reference. I fiddled a bit. See the “cherry picking” admission? I took the 1979- now data, and tested which level results in the most “improvement” of the fit for that, measured by the best R value by varying the location of the ‘peak’ and the magnitude of the amplitude.
I admit I groused– but I do always feel the need to read a bit to see if shoving in a “fix” really makes sense. I’m still not sure the climatologists totally or mostly agree that there is a 0.1 C peak-to-trough. I still think that if they think there is a ±0.1C effect that is as predictable as the sun, they ought to mention this quite prominently and very near the actual projections.
No matter what, they will be re-evaluating before 2014, and like it or not, it’s best to consider data that really, honestly came out after predictions were made. Even with 14 years, a ±0.1C for with an 11 year period is important especially if you use “slide and eyeball”, as done in Rahmstorf, or the validations portions of the IPCC.
Sorry, I wasn’t very clear. I meant peak-to-trough. I agree with your assessment of plus or minus 0.05C…
…and now I see my mistake. I thought you were applying a correction for a solar influence of -0.05C from Jan2001 to Jan2008. I now understand that you are using a circular solar cycle with an amplitude of 0.05C. Sorry for my confusion.
I’ve been toying with adding a simulated solar cycle GMST response to GIS temperatures. I took the solar forcing from the data file you used for Lumpy, subtracted a running 11-year mean, and scaled it to temperature with a peak-to-trough of 0.1C. I ran a couple of analyses with this simulated temperature response added and subtracted from the GIS temperatures. The FFT amplitudes at the 11-year period were:
Raw GIS: 0.022 degC
GIS + Sim: 0.040 degC
GIS – Sim: 0.01 degC
There are a few things to note from this:
1. There is something wrong with the scale;
2. The response nearly doubles when adding 0.1C solar response;
3. The response is nearly eliminated when removing 0.1C solar response
This calls into question my FFT analysis of the Model E response to solar forcing. It *may* suggest that the raw GIS temperatures show approximately 0.1C peak-to-trough for the solar cycle.
I don’t have any FFT codes handy, so… But maybe someone will run it. I ran across interviews were various climatologists claim the AOGCMs do reproduce 11 year long variability, and others that say they don’t. So, I don’t know what’s claimed.
But in the table in chapter 10 of the scientific basis for the AR4, the GISS models listed “Y” and “Y” for accounting for solar. If AOGCM showed no response, I’d be surprised they would bother to integrate in the SRES. I’m saying this because… well… I wouldn’t go to the effort to add complexity to predict no response. Other models listed “C” and “C”.
Ok, I’ve played with my simulated temperatures on top of GISTEMP temperatures a little more. To me, they suggest an 11-year cycle with a peak-to-trough amplitude of ~0.13C.
When I subtract a 0.13C temperature response to the solar cycle (with the exact shape of the actual solar forcing), the FFT at ~11Hz drops to near zero. When I add the same temperature response, the FFT at ~11Hz doubles. I think the assumption of a circular solar cycle makes the response hard to find. It is easier to find using the actual shape of the solar cycle (faster rise, slower decline).
I concede that my method may be completely invalid. Anyone interested in testing?
John– do you have literature on the actual shape? Or do you calculate it based on the published TSI?
Initially, I was thinking of looking at the published TSI, but then I thought I’d do quick and dirty first. (I’m not sure one can do much better than quick and dirty with this.)
One of the issues with comparing “with an 11-year cycle” is that the sunspot cycle is, in itself, weather. Solar weather. We’re currently in our thirteenth year from the last sunspot minima, with not much sign of the next cycle beginning. Then you add potential lags, and the uncertainty in what precisely should be the significant solar parameter.
I’d be interested in this question:
If you compare just the years of the sunspot maximas, what is their distribution compared to the all-years-trend? If there’s an unknown-but-real contribution for which sunspots are a reasonable proxy, one would expect ‘the maxima’, or perhaps ‘the year after the maxima’ to have a decidedly non-gaussian distribution across the trend.
IOW: Before saying “Do I see an 11-year periodicity?” ask the blank-slate empirical question “Is this factor of any interest?”
lucia,
I did not calculate the shape. I just used the published TSI, de-trended, scaled it to +/-0.05, and added or subtracted it from GISTEMP historical temperatures. I then used Excel’s FFT on the last 64 years of data.
I would prefer to use monthly data but yearly was on my hard drive. I also need to figure out Excel’s FFT scaling or finally make the switch to R.
Alan Blue–
There are lots of interesting question. My main one is: The IPCC accounted for certain things in their projections. But, evidently not others. Does the flat trend seem to be due to the things they didn’t account for in their projections.
It is interesting that the sun spots are not materializing on time. I’m not going to be looking into the sunspot- sun intensity link though. I think plenty of people have that covered! 🙂
Lucia are you familiar with this multivariate analysis?
Douglass, D.H. and B.D Clader, 2002, Climate sensitivity of the earth to solar irradiance,
Geophys. Res Lett. vol 29, no. 16, 10.1029/2002GL015345
Hans– I haven’t read that. I know Gavin and someone were arguing about it over on a thread that Brigg’s blog.
here is figure 2 of DC2002
I did an FFT analysis of monthly sunspot data (1850 through 1995) from NGDC, and eliminated all harmonics except those required to produce a wave-form that closely matched that of the smoothed envelope of monthly sunspot numbers. Those harmonics ranged from approx 7 to approx 15 year periods. I then ran an FFT analysis of monthly global temperature anomalies (1850 through 2008) HADCRUT3, eliminating all harmonics except the those used to generate the sunspot-envelope waveform. Interestingly, the resultant temperature wave-form was quite similar to the sunspot waveform, and the peak-to-peak temperature was very nearly 0.1 deg C on average. However, phase-relationships between the two waveforms were all over the place, ranging from in-phase to 180 degrees out-of-phase and back, with no discernible pattern.
From this analysis, any relationship of temperature to sunspot cycles seems suspect, and it is questionable whether the 11-year component of the temperature signal can be definitively ascribed to solar cycles, at least with simple mathematical/statistical procedures. Is it possible that there is a mechanism that transfers sunspot-related energy to the atmosphere with varying amounts of lag?
Since the sunspot cycle periods vary significantly in length, no single sine-wave can adequately describe the wave-form, however 6-8 harmonics, with periods ranging from 7 to 15 years, will reproduce the smoothed data very well. I also used Excel’s FFT routines, as I am not yet well-acquainted with R.
I did de-trend the temperature data, and zero-padded both sets of data to eliminate end-effects and to raise the number of input data to 2048.
Lucia,
I don’t think it makes sense to include ENSO correction and the solar correction in the same analysis since they are are likely one in the same (i.e. solar maxes correspond to El Ninos and solar mins correspond to La Ninas). This could mean that the solar correlation is accidental or their is an unknown link between the solar cycle and ENSO. In either case, using the solar effect to avoid falsifying the 4AR predictions does not actually help the IPCC cause because they cannot explain why the solar cycle has the effect claimed.
Raven: Regarding your statement that El Ninos correspond with Solar Maximums and La Ninas with Minimums, I find no correlation between MEI and TSI.
http://i26.tinypic.com/292lisg.jpg
The MEI is annual data and I subtracted 1366 from the TSI to scale it.
Raven:
I agree that adding Solar doesn’t necessarily help the IPCC case. But, it is useful to see if any particular mechanism with longer periods, and that is omitted from the projections, and that particular one, suggested by JohnV, happens to do it. If climatologists were to say they believe that effect is there, and fairly well know to follow the sun’s cycle, I would suggest they should then be incorporating that into the projections. Given the range of warming predicted, and the true time frames for assessing validity (which, no matter what they say, is from the publication of one report to the time they start writing the next) it’s to big to just ignore.
I’d been looking at AMO, and at least from what I read, while it’s a long period, that switch can’t be the cause. The other issue is PDO– that switched around the right time. But I haven’t found any estimates of how much temperature variation that might cause from peak to trough.
Oddly, I looked at the standard deviation of temperature for the GISS “solar” runs, and they aren’t far off from the ones we see in recent data. That’s interesting because the GISS solar runs don’t have volcanic activity. The match sort of implies this time period is long enough to get roughly correct error bars, as those do scale with the standard deviation. (I need to look a bit more and consider the “measurement noise”, but they really aren’t far apart.)
Bob–
I think Judith Lean suggested solar may trigger something but not necessarily ENSO. I need to collect some of these papers together, but it appears at least some thing the solar connection may not be the actually magnitude of TSI, but an indirect response. ENSO cycles are shorter than 11 years.
lucia I checked the MITGCM code for incorporation of an 11 year cycle, I couldnt find any. Next I’ll check modelE
i started with MIT because its better documented, with modelE i’ll have to slog through code, or write gavin.
the former being more fun
Those rabbits and others who claim there is no evidence of the solar cycle in the temperature record should try looking at some data. Look at HADCRUT3 and you see peaks at roughly 1940, 1950, 1960, 1970, 1980, 1990. Now look at the sunspot data for example here and what do you see? Peaks around 1940, 1950, 1960, 1970, 1980, 1990.
Note that in the late 20th century the solar cycle length is about 10.5 years. The cycle tends to be shorter when the amplitude is large and longer when it is weaker.
I thought the premise (AGW) was that the sun had NO effect on climate (AGW) but now it seems it may. after all…LOL
Bob Tisdale says:
The match is not perfect because there are additional wiggles but the pattern is consistent: as the cycle falls from max to min the mei goes from high to generally low (with blips). The reverse happens on the rising edge. There is enough of a pattern to say that any observed correlation between solar cycles and temps could be simply be picking out one of the patterns in the MEI.
as long as the sun nuts dont dominate or derail the discussion, I’m ok with it.
I’d boil it down to one question. When the GCM contributing to the IPCC make a “forecast”
do they assume a constant solar forcing or varying forcing. If varying, then how
is this implemented.
Is that the right question? JohnV care to weigh it, before I shoot an email to gavin
anonymous:
The premise of AGW is *not* that the sun has no effect on climate. That’s the strawman that some use to confuse things. The IPCC position is that many things affect climate, including greenhouse gases. It is the position that greenhouse gases have no effect.
Raven:
Do you have any references or analysis for your purported relationship between ENSO and the solar cycle?
lucia:
As you know, the IPCC assessment reports are basically literature reviews. If we want to know the “opinion” of the IPCC regarding the solar cycle, then we should use the references cited in the IPCC AR4 WG1 9.2.2 (listed below). The text of AR4 is pretty clear about 0.1C peak-to-trough and there is no mention of any controversy. Tamino and Eli seem to disagree but have not published anything.
The solar cycle effect on trends is significant for this analysis only because of the unfortunate coincidence with the solar cycle.
—
IPCC AR4 Solar Cycle References:
van Loon and Shea, 2000:
van Loon, H., and D.J. Shea, 2000: The global 11-year solar signal in July-August. Geophys. Res. Lett., 27, 2965–2968
Gleisner and Thejll, 2003:
Gleisner, H., and P. Thejll, 2003: Patterns of tropospheric response to solar variability. Geophys. Res. Lett., 30, 44–47.
Haigh, 2003:
Haigh, J.D., 2003: The effects of solar variability on the Earth’s climate. Philos. Trans. R. Soc. London Ser. A, 361, 95–111.
White et al., 2003:
White, W.B., M.D. Dettinger, and D.R. Cayan, 2003: Sources of global warming of the upper ocean on decadal period scales. J. Geophys. Res., 108, 3248, doi:10.1029/2002JC001396.
Coughlin and Tung, 2004:
Coughlin, K., and K.K. Tung, 2004: Eleven-year solar cycle signal throughout the lower atmosphere. J. Geophys. Res., 109, D21105, doi:10.1029/2004JD004873.
Labitzke, 2004:
Labitzke, K., 2004: On the signal of the 11-year sunspot cycle in the stratosphere and its modulation by the quasi, biennial oscillation. J. Atmos. Solar Terr. Phys., 66, 1151–1157.
Crooks and Gray, 2005:
Crooks, S.A., and L.J. Gray, 2005: Characterization of the 11-year solar signal using a multiple regression analysis of the ERA-40 dataset. J. Clim., 18(7), 996–1015.
steven mosher:
I would expect that if the solar cycle influence is fed into the models, it would be through a data file of TSI. I really hope there’s no 11-year cycle in the code — that would be sloppy even for research code. Your question seems like the right one and it can’t hurt to ask. He may only be able to answer for NASA’s models.
I think lucia found a table that shows which models include the solar cycle (something about “Y” and “C”). If I understood her correctly, only some models consider the solar cycle.
I’m going to have a look at the Model E response again and try to figure out how Excel scales FFT results.
JohnV– Yes. I know they are basically literatures review. And I agree that information is in the literature review section.
But the IPCC also make projections, and make some decisions as to what to include in the forward integration. Those projections aren’t just the literature review, and some things in the literature review are ignored in the projections. The section on projections says so. They also make decisions to include some effect directly in their uncertainty intervals (through the SRES etc.)
So… that’s where things get fuzzy for me. I tend to believe that the things the IPCC consistently include when doing their integrations to make projections tell us something about their “opinion” about “what matters”. The things they ignore– even though mentioned in the literature review, they collectively think matter yes.
(Or, I think this in so far as any group can have an “opinion”. That’s actually a difficulty with the idea. Each author and contributor likely has their own opinion. To some extent, that’s why everything ends up in the literature review, whether or not “everyone” or even “most” of those working on the IPCC document agree with it. )
That said, I would hardly insist that everyone take my point of view on this interpretation. Maybe appearance in the more “literature review” type sections does mean the IPCC as a group believes something.
I think both of us agree information is in there but have disagreements as to the plausible intended meaning or what a typical reader is likely to interpret based on the manner of organization of the document etc.
So, basically, I think we’re in a position where we can both keep repeating what we are saying. But some of this is matter of opinion not about the “truth” of AGW, but about theories of what might be in the “collective head” of a body of people, and/or how the information is likely to be interpreted by readers.
It is obvious that some quite vociferous bloggers have been stating their opinions in ways that sound like they are telling people — rather vehemently — that “there is NO, NO, NO discernable effect”. And they don’t mean just averaged over time- they mean even considering the dip as being affected by solar is somehow nuts.
Steve M:
There is a question regarding does the IPCC include solar! There is a table in chapter 10 that shows “effect” and then includes little letters (Y, C, N, etc.) saying what they include. “Y” means they include an effect; “C” means the include it in AOGCM’s but not SRES integrations, and N means they don’t use it. There is also NA etc. Solar has a “Y” for the GISS model E, but no where else. For other cases, they have “NA” (not applicable) or “C” or “N”. I’ll reproduce this, but likely on Tuesday. (We’re waiting for stain to dry today. Mom’s visiting tomorrow- it’s my birthday sunday etc.)
John V says:
I am not saying there is a proven causal link. I am saying is any that analysis like Camp and Tung which attempts to quantify the solar effect by looking for correlations between the solar cycle and the temperature record will end up including the effect of ENSO. This could mean that the correlation is accidental and therefore meaningless or that there is some unknown causal link. In either case it does not make sense to do an analysis that corrects for ENSO and adjusts for the solar cycle.
More importantly, the paper you referenced in the other thread indicates that a 350 w/m2 change in TSI over the NH mid-latitudes produces a 10 degC change in temps. The solar cycle adds <1 w/m2 pertubation to that 350 w/m2 annual change. I don’t see how such a small pertubation could possibly produce a 0.1 change in GMST. This is a point that Leif has been making repeatedly in his thread on CA.
In other words, if one accepts the premise that the solar cycle has a 0.1 degC effect on GMST then must also accept that this effect is driven by something other than TSI. If the effect is driven by some unknown mechanism then you cannot assume that it averages out over many cycles.
Here are some numbers to back up what Robert Beck and I am saying. Take the monthly sunspot numbers and HADCRUT3 from 1940-1999. Detrend them and then take the FFT of each (scaling is arbitrary and doesn’t matter – John V take note). Ignore the first number which is the mean, zero after detrending. For the sunspots, the first 7 mode amplitudes are:
4.7 18.8 1.4 9.5 29.9 48.3 24.4
Note the peak at the 6th mode corresponding to 10 years (60/6). As I said above, recent solar cycles have been closer to 10 than 11 years. Now the numbers for HADCRUT3 are
40.5 14.6 22.4 11.9 1.9 20.0 14.4
and again we see a peak at 10 years, which as mentioned above can be seen clearly in the smoothed HADCRUT3 graphs.
Of course, all this may be just coincidence – two unrelated oscillations that happen to have similar periods!
ok, lucia I’ll wait to see your post before bugging gavin.
Raven:
The amount of energy in the solar cycle is roughly 11% of the energy in the annual cycle…
11-years is different than 1-year…
The oceans moderate atmospheric response, particularly at high frequencies…
Douglass and Clader (2002) found 0.1C for the solar cycle even after regressing on sea surface temperature…
I believe ENSO occurs in models without requiring a solar cycle…
ENSO is a transfer of heat between oceans and atmosphere and is very different than an external forcing…
…
Never mind.
—
lucia:
I understand your position a little better now. I’ll let you have the last word and stop repeating myself.
The fact that most of the models exclude the solar cycle explains why the solar cycle “wiggles” do not show up in the IPCC projections. You are also probably right that many of the modellers did not think it was important. You are also right that they should have included the solar cycle in their model runs rather than deciding a priori that it was not important.
—
PaulM:
Thanks for the extra info. I realize that the FFT scale is not important when looking for important frequencies, but it is important to determine the scale of the response at a particular frequency. IMO, FFT breaks down a little for the solar cycle because it is not sinusoidal and because its frequency is close to other internal cycles (eg ENSO).
I just spent a little more time looking at the Model E results.
It looks like my original numbers were correct — the Model E peak-to-trough solar cycle temperature response is only about 0.03C.
John V says:
600/1366 = 45% of solar irradiance on the NH mid latitudes at the summer solstice.
1.5 w/m2 = peak to trough change in irradiance over the solar cycle (from graph posted on the Svalgaard thread for cycle 23).
350 w/m2 change = 10 degC change in NH mid latitudes
1.5 * 45% = 0.675 w/m2
0.657/350 * 10 = 0.019 degC
which is amazingly close to your Model E calculation.
Here is a paper on ENSO solar link: http://rainbow.ldeo.columbia.edu/~alexeyk/Papers/Emile-Geay_etal2007inpress.pdf
BTW – the paper is by noted warmer Julian-Emile Gauy
Raven, so *now* you believe the models? 🙂
There’s actually a 15degC change in NH mid-latitudes, which makes the agreement even better. So you’re conclusion must be right, except for a couple of complications:
– the same TSI change in the SH mid-latitudes only causes a 5degC change;
– roughly double the TSI change in the tropical latitudes only causes a 4degC change
I guess it’s not quite that easy after all. Oh well.
By the way, if Model E is your standard I’ll make you a deal:
I’ll accept that the real sensitivity to the solar cycle is only 0.03 degC if you accept that the sensitivity to doubling CO2 is ~2.5 degC. Deal?
Raven — thanks for the reference for the ENSO-solar link.
John V says:
To be fair we are only comparing the output of two models (the “back-of-envelope” model and ModelE). I realize that this is a complicated topic but all we really can establish is order of magnitude at this point.
Also, I don’t have an issue when people treat GCMs as a fancy calculator and use them to explore hypotheses. GCMs only become problematic when their outputs are treated as proof that a hypothesis is correct. In my opinion only real world experiments can demonstrate the correctness of a hypothesis.
Ok.. In an article complaining that someone makes to much of one data point,Tim Lambert argues, evidently based on one data point:
Of course, Lambert’s observation about the lack of coldness in 1997 tells us little about the likelihood of a link. But, since I’m trying to figure out what people tend to think about the link, I can’t help noting bloggers comments about stated links.
The 11 yr solar signal cannot be modelled simply as a variation in TSI. That would be a naive way to look at things. Furthermore, inferring the extent of the solar influence from an FFT analysis is just as naive. It’s all a question of whether this is a linear transfer function or not, and most likely it isn’t. If there is a non-zero response time (or multiple response times), the modulation itself may seem weak, but the influence may still be large, and will be seen as long term trends. I understand that this may not be relevant to this particular argument (whether including the solar cycle means the IPCC projection is falsified or not), but in the end it is the full extent of the solar influence that counts. As an example, if you try to correlate CO2 with temperature, you might find that the correlation is very poor, and conclude that CO2 has no effect, and all the AGWers will tell you it’s not the right way to look at things. So why use the same argument with the Sun?
Anyway, there is another paper by U. Langematz et al., “Solar impact on climate: modeling the coupling
between the middle and the lower atmosphere”, Mem. S.A.It. Vol. 76, 868, which should be of interest to this discussion. The authors are from the same institute as Karen Labitzke in Berlin.
Excerpt from the abstract (emphasis is mine):
And the conclusion:
BTW the paper is not cited in IPCC chap.9. None of the authors is an IPCC author. Lucia, there is no such thing as the IPCC “as a group”. Each chapter is written by a select group of authors, and is a very selective literature review. Some subjects are carefully avoided, especially all papers that point to model deficiencies and the like. Researchers who are not strong AGWers (meaning they don’t make a carreer writing papers on potential catastrophic effects of GW, but try to advance our understanding of the physical world) are not invited to participate in the redaction, or the review. It is always touted that thousands of scientists participate in the report, but what is never said is that thousands more do not participate.
Francois O:
I totally agree with this:
JohnV had suggested that we could learn what the IPCC opinion on something is by looking at citations in a particular chapter. My view is: We can’t entirely do that because I’m not sure there is such an animal as the IPCC’s opinion. It’s always difficult with documents written by really big groups. Individual people have opinions. Groups don’t.
Where I think JohnV’s point is valid is: At least some papers cited suggest there is a link, it’s in phase, and it’s this big from peak to trough. If so, and we hit it “just right” (or wrong as it were) that could explain the downturn.
But, I’m not so sure that many believe there is such a clear, distinct, in phase link. In fact, it appears most pro-AGW bloggers spend quite a bit of time and energy insisting there is no discernable link. (This is true to the extent that we see many of the ridiculing the notion there could even be a link!)
The main thing: If you get a “falsification”, it’s always useful to try to find out if there is any identifiable thing (mechanisms, known energy at long periods etc.) that could ’cause’ the statistical anomaly. So far, this one– if true— could cause it.
Did it? Don’t know. Could it? Don’t know! If solar is the reason for the non-warming, we should see very rapid warming as we come out of the trough — and that’s supposed to be soon.
But other than the one JohnV pointed to, all other suggestions are fairly vague. JohnV’s is at least concrete. That means we can actually discuss its merits, possible impact etc. Obviously, my introduction into the test is way oversimplified– but it does indicate an order of magnitude.
Lucia,
The question seems to be: does the IPCC include the solar cycle in their GCM projections. But as far as I know, the IPCC does not do simulations. Various groups using various GCM’s perform simulations, and the IPCC merely re-reports results that have already been published. So the real question should be: what GCM’s are used in the IPCC reports, and how do these GCM’s include solar forcing and its fluctuations.
But let me ask a related question. If you know that the current GCM’s do not accurately reproduce the solar cycle (as seems to be the case from the reference I gave, and I’ll give another one below), then what do you do? Does that falsify all simulations from those GCM’s? To what degree can you trust those simulations? It’s a question to which there is no simple answer (if there is one at all!): what degree of confidence can you have in an imperfect model? A simple answer would be: you should quantify the degree of imperfection, but to do that, you need some criterion, and there is just no simple criterion that can be used. Even a perfect agreement with past data is no guarantee because, as I said in an earlier comment, we’re talking about extrapolation here, not interpolation.
Anyway, here’s another paper by the same group, the title says it all: “Towards a better representation of the solar cycle in general circulation models”, by K.M. Nissen et al., Atmos. Chem. Phys., 7, 5391–5400, 2007. Note that it was published too late to be included in the IPCC 4AR.
From the introduction (again emphasis is mine):
And the conclusion:
Raven,
I quickly browsed the JEG paper that you referenced above regarding a link between the solar cycle and ENSO. I could find nothing in that paper related to the Schwabe cycle. From my reading it only discusses links at century and millenium scales. Please point me to the appropriate section if I missed something.
—
Francois O,
I agree that the effect and the mechanisms of the Schwabe cycle on GMST may be difficult to understand. It does seem that the correlation is fairly well accepted empirically (I have not seen any papers that argue against the correlation) even if the mechanisms are not well understood (models seem to under-estimate the effect). IMO the multi-variate analysis of Douglass and Clader (2002) looks pretty solid, although I read it months ago and don’t remember all the details.
—
lucia,
I am aware of Tamino showing that the effect of the solar cycle in temperatures must be small (~0.05degC?) and Eli’s comments about the relationship not existing. Do you have any other examples of “many of them ridiculing the notion that there could even be a link”? I’m looking for counter-arguments. Thanks.
Francois O,
That looks like a very interesting paper. I hope I can find/make the time to read it.
I have a quick comment about one sentence in the introduction. It doesn’t materially affect the conclusions but I think it’s interesting. The authors state:
So the peak TSI is 1.0008 times the trough TSI. The expected temperature change without any feedback is ~288K * (1.008)^(1/4) = 0.06K. Melt a little ice or add a little water vapour for feedback and the temperature could potentially swing 0.10K.
you know JohnV there are two topics I have sworn off discussing, C02 ( cause its settled science) and solar
because it attracts pagans. ( just kidding ) Nevertheless I believe you will find some quotes from Hansen
supporting your position. In his explaination of 2007 temps I believe he made note of the fact that the
temps where high, DESPITE entering an El Nina and despite having lowish solar forcing. FWIW.
On a side note I find it funny that a bunch of people assert that you need 10-15 years to ESTABLISH a trend,
When what lucia is trying to do is RULE OUT a trend. prove versus disprove. Ok now that I flashed my Popper badge
I’ll re lurk.
Good to see you around again. I had not mentioned that before, so pardon the delay
steven mosher:
I’m slowly learning the key blog commenter lessons. No more CO2 battles for me. Avoid solar as much as possible. If solar is necessary, strictly avoid cycles longer than Schwabe and Hale.
I saw Hansen’s comments re 2007 temps. He suggests a 2-year lag between the solar cycle and temperatures. I enjoy that Hansen and his bulldog seem to disagree on this one. Raven is arguing for a weak solar effect. Cats and dogs sleeping together. Mass hysteria!
Thanks for the welcome back. This is a nice neighbourhood. Very civil. Minimal lynchings. Few circular firing squads.
JohnV– Yeah… I overstated. I’d just been at Lambert’s blog. I interpret his comments to suggest he doesn’t think there’s much solar effect, and he was ridiculing someone and linking to other ridiculing that person. But, I think the ridicule was more for suggesting the imminent ice age.
Now…. I think I need to go bake myself a birthday cake. (Tomorrow is my birthday. Mom is visiting with presents.) 🙂
lucia, that wasn’t supposed to be a “gotcha”.
Happy Birthday — enjoy the weekend.
Happy Birthday then!
Thanks John and Francois!
John V says
I am only arguing that the TSI driven component of the solar effect is minimal. Indirect solar effects likely exist and we can infer them by looking for correlations between the 11 year cycle and the temperature record. Hansen can jump on the solar cycle as a way to support his claims but it does not really help his case unless he can explain why the solar effect exists and demonstrate that there is no long term trend.
It is probably worth reviewing what started the long Svalgaard threads at CA: http://www.climateaudit.org/?p=2470
Leif is quite skeptical when it comes to any solar climate link and he seems to argue that TSI changes are too small to have an observable effect unless TSI sensitivity is very high. However, if TSI sensitivity is very high then we should see it show up in many other situations (e.g. annual orbital eccentricity). If there is no evidence for high TSI sensitivity in other situations then one cannot conveniently assume that any inferred solar cycle-temperature link is driven entirely by TSI.
lucia since you enjoy turbulance head over to RC today
happy B day! Lucia.
Francois O and Lucia, You’re right that there’s no such thing as the IPCC ‘as a group’ (comments 2258-59 above): the 3 Working Groups (WGs) operate as independent fiefdoms. On 4 July 2004 I complained to Chairman Pachauri about the Panel’s wasteful use of different combinations of scenarios in what is supposed to be an integrated assessment.
The Working Group on Climate Models (WGCM) Climate Simulation Panel of the World Climate Research Program (WCRP) had just called for expressions of interest from climate modelling groups in participating in ‘an unprecedented set of coordinated … climate change experiments’. The WGCM specified that the runs to be performed by all of the groups were to include simulations of three SRES marker scenarios: A1B, A2 and B1.
Meanwhile IPCC WGII, proceeding independently, had decided to ignore A1B and to use A1FI (FI = fossil fuel intensive) instead. The April 2004 issue of ‘Global Environmental Change: Human and Policy Dimensions’ featured a series of assessments of projected climate change impacts which were based on 2 scenarios that were used in the WGCM exercise – A2 and B1 – and 2 that were not – A1FI and B2. An introductory comment by Professor Martin Parry (Editor of GEC and Co-Chair of IPCC WGII) said that these studies would ‘form a valuable background for the Fourth Assessment of the IPCC.’
The release of the Economic Affairs Committee of the UK House of Lords report on ‘The Economics of Climate Change’ in July 2005 was followed by a hilarious discussion of the IPCC scenarios at RealClimate (‘Lawson vs the IPCC’). In his initial post (9 November 2005), gavin claimed that the emission scenarios were used SOLELY for providing input into climate models, and not for generic economic planning decisions’ (EMPHASIS added). When I pointed out that the A2 projections that were used in both the WGI and WGII studies assumed an end-21st century global population of more than 15 billion – well above the upper limit of the 95% confidence range of the probabilistic projections produced by IIASA (which had prepared the SRES population projections in the first place) – ray-pierre argued that ‘An improbable event with very bad consequences … is much more relevant for policy decisions than an improbable event in which events are less severe.’ Well yes, but weren’t the scenarios to be used solely as input for climate models? ray-pierre went on to ask whether I thought that climate modellers had ‘an infinite amount of time [for] doing scenarios’? No, not at all: I’d just wondered why modellers could devote such enormous effort to exploring projections that had virtually no prospect of being realised in the real world.
Meanwhile, william took the opposite tack, arguing that there was ‘a very good case for people like the HoL Economics Committee, or Castles and Henderson, getting off their bums and actually generating their own scenarios instead of just criticising from the sidelines.’ This remark prompted economist Richard Tol to expose some home truths about the IPCC and its supporters:
‘Nowadays, to get a paper published, one needs to run the benchmark SRES scenarios as well. The reason that there [are] so few alternatives to SRES, and no prominent ones, has to do with funding. Scenario development is expensive. Funding agencies are not interested because there is SRES, and the SRES in-crowd is fighting tooth-and-nail to maintain their lucrative monopoly.’
Earlier, Professor Tol had explained to the Lords Committee that ‘Essentially in Germany, for working groups 2 and 3, only people with connections to the Green Party have been nominated to the IPCC, and that excludes me immediately’ (Evidence, p. 76). In any other field, such a serious allegation about a supposedly disinterested body would have led to calls for an inquiry. But in the area of climate change it seems to be ‘par for the course’.
It does look like they are re-evaluating what scenarios to run! I’m just waiting and seeing what happens with projections/ predictions.
John V: Eli started a thread linking to Phil Chapmans discussion of the solar minimum & imminent iceage, and now, we a blogger declaring his views on the solar minimum:
From Fermi Paradox
The link points to skeptical science.com, which discusses the effect of solar activity on warming. But, the article doesn’t seem to discuss the impact of the 11 year cycle so much as it discusses longer term variations. The
skeptical science page has links to lots of discussions, and so is of interest to those curious about the solar influence.
It is probably beyond the scope of the project, but it might be interesting to look at each model’s results on an individual basis. Presumably some of the individual models would be falsified and you could look at the criteria for a model to be included in the IPCC and determine which lead to inadequate models.
There is an updated version of the analysis that Hans mentioned above:
http://arxiv.org/ftp/physics/papers/0411/0411002.pdf
Looking at the residuals, It seems to me like spontaneous downward trends do occur that have nothing to do with the solar cycle, so it could also just be a strange random deviation (though I suppose that isn’t much of an answer).