BEST, Volcanoes and Climate Sensitivity

Guest Post by Willis Eschenbach

I’ve argued in a variety of posts that the usual canonical estimate of climate sensitivity, which is 3°C of warming for a doubling of CO2, is an order of magnitude too large. Today, at the urging of Steven Mosher in a thread on Lucia Liljegren’s excellent blog “The Blackboard”, I’ve taken a deeper look at the Berkeley Earth Surface Temperature (BEST) volcano forcings. It’s a curious tale, with an even more curious outcome. Here’s the graph in question:

Figure 1. BEST comparison of hindcast temperature changes due to CO2 plus volcanoes (heavy black line) with the BEST temperature data (light black lines). SOURCE

I asked Steven Mosher where the BEST folks got the data on the temperature change expected from volcanic forcing as shown in the heavy black line above … no reply. Setting that question aside, I decided to just use the data I had. So … I did what I usually do. I digitized their figure, since their underlying data wasn’t readily available. That allowed me to analyze their data, which revealed a very odd thing.

Their explanation of the black line in Figure 1 above (their Figure 5) is as follows:

A linear combination of volcanic sulfates and CO2 changes were fit to the land-surface temperature history to produce Figure 5. As we will describe in a moment, the addition of a solar activity proxy did not significantly improve the fit. The large negative excursions are associated with volcanic sulfate emissions, with the four largest eruptions having all occurred pre-1850; thus our extension to the pre-1850 data proved useful for the observation of these events. To perform the fit, we adjusted the sulfate record by applying an exponential decay with a two year half-life following emission. The choice of two-years was motivated by maximizing the fit, and is considerably longer than the 4-8 month half-life observed for sulfate total mass in the atmosphere (but plausible for reflectivity which depends on area not volume).

OK, that makes me nervous … they have used a linear regression fit to the temperature record of the lagged exponential decay, with a separately fitted time constant, of an estimate of volcanic sulfate emissions based on ice cores … OK, I’ll buy that, but at a discount. They are using the emissions from here, but although I can get close to the figure above, I cannot replicate it exactly.

I wanted to extract the volcanic data. My plan of attack was as follows. First, I would digitize the heavy black line from Figure 1 above. Then I’d match it up with the logarithm of the CO increase since 1750. Once I subtracted out the CO2 increase, the remainder would be the hindcast change in temperature resulting from the volcanic eruptions alone.

Figure 2 shows the first part of the calculation, the digitized black line from Figure 1 (CO2 + volcanoes) with the log CO2 overlaid on it in red.

Figure 2. The black line is the digitized black line from Figure 1. The red line is three times the log (base 2) of the change in CO2 plus an offset. CO2 data is from Law Dome ice cores 1750-1950, and from Mauna Loa thereafter.

I fit the CO2 curve to the data by hand and by eye, by manually adjusting the slope and the intercept of the regression, because standard regression methods don’t fit it to the top of the black line. A couple of things indicated to me that I was on the right track. First is the good fit of the log of the CO2 data to the BEST data. The second is that it turned out that the best fit is when using the standard climate sensitivity of 3°C for a doubling of CO2. Encouraged, I pressed on.

Subtracting the volcanic data from the CO2 data gives us the temperature change expected from volcanoes, as shown in Figure 3.

Figure 3. Volcanic temperature changes (cooling after eruptions) as hindcast by BEST (black line), and as fit from the lagged emissions as described in their citation above (red line).

Note that as I mentioned above, I can get close to the temperature changes they hindcast (black line) using a lagged version of their sulfate data as they described (red line), but the match is not exact. Since the black line is what they show in Figure 1 above, and the differences are minor, I’ll continue to use the heavy black line.

Now, let’s pause here for a moment and consider what they have done, and what they have not done. What they have done is converted changes in atmospheric CO2 forcing in watts per square metre (W/m2) to a hindcast temperature change (in degrees C). They did this conversion by using the standard climate sensitivity of 3°C of warming for each doubling of CO2 (doubling gives an additional 3.7 W/m2).

They have also converted stratospheric injections of volcanic sulfates (in Teragrams) to a hindcast temperature change (in degrees C). They have done this by brute force, using a lagged model of the results of the stratospheric sulfate injections which is fit to the temperature.

But what they haven’t done, as far as I could find, is to calculate the forcing due to the volcanic eruptions (in W/m2). They just fitted the sulfate data directly to the temperature data and skipped the intermediate step. Without knowing the forcing due to the eruptions, I couldn’t estimate what climate sensitivity they had used to calculate the temperature response to the volcanic eruptions.

However, there’s more than one way to skin a cat. The NASA GISS folks have an estimate of the volcanic forcing (in W/m2, column headed “StratAer” for stratospheric aerosols from volcanoes). So to investigate BEST’s climate sensitivity, I used the GISS volcanic forcings. They only cover the period 1880—2000, but I could still use them to estimate the climate sensitivity that BEST had used for the volcanic forcings. And that’s where I found the curious part. Figure 4 shows the volcanic forcing in W/m2 from NASA GISS, along with the BEST hindcast temperature response from that forcing.

Figure 4. Black line shows the BEST hindcast temperature anomaly (cooling) from the eruptions. Red line is the change in forcing, in watts per square metre (W/m2), from the eruptions. Green line shows the best fit theoretical cooling resulting from the GISS forcing. Note the different time period from the preceding figures.

As you can see, the regression (green line) of the GISS forcing gives a reasonable approximation of the BEST temperature anomaly, so again we’re on the right track. The curious part is the relative sizes. The change in temperature is just under a tenth of the change in forcing (0.08°C per  W/m2).

This equates to a climate sensitivity of about 0.3°C per doubling of CO2 (0.08°C/W/m2 times 3.7 W/m2/doubling = 0.3°C/doubling)… which is a tenth of the canonical figure of three degrees per doubling of CO2.

So in their graph, in the heavy black line they have combined a climate sensitivity of 3°C per doubling for the CO2 portion, with a climate sensitivity of only 0.3°C per doubling for the volcanic portion …

Now this is indeed an odd result. There are several possible ways to explain this finding of a climate sensitivity of 0.3°C per doubling. Here are the possibilities

1. The NASA GISS folks have overestimated the forcing due to volcanoes by a factor of ten, a full order of magnitude. Possible, but very doubtful. The reduction in clear-sky sunlight following volcanic eruptions has been studied at length. We have a pretty good idea of the loss in incoming energy. We might be wrong by a factor of two, but not by a factor of ten.

2. The BEST temperature data underestimates the variation in temperature following volcanic eruptions by a full order of magnitude. Even more doubtful. The BEST temperature data is not perfect, but it is arguably the best we got.

3. The BEST data and the NASA data are both wrong, but providentially they are each wrong in the right direction to cancel each other out and give a sensitivity of three degrees per doubling. Odds are thin on that happening by chance, plus the reasons above still apply.

4. Both the NASA and BEST data are roughly correct, and the climate sensitivity actually is on the order of a tenth of what is claimed.

Me, I go for door number four, small climate sensitivity. I say the climate is buffered by a variety of homeostatic mechanisms that tend to minimize the temperature effects of changes in the forcing, as I have discussed at length in a variety of posts.

However, as always, alternative hypotheses are welcome.

Regards to everyone,

w.

DATA: I did this on an excel spreadsheet, which is here. While it is not user-friendly, I don’t think it is actively user-aggressive … the BEST temperature data on that spreadsheet is from here. Note that curiously, the BEST folks have not removed all of the annual cycle from their temperature data, there remains about a full degree of annual swing … go figure.

[UPDATE] Richard Telford in the comments points out that what I have calculated is the instantaneous sensitivity, and he is correct.

However, as I showed in “Time Lags in the Climate System“, in a system that is driven cyclically and that picks up and loses heat via exponential gain and decay, the instantaneous sensitivity is related to the longer-term sensitivity by the relationship

where t1 is the lag, t is the length of the cycle, and s2/s1 is the size of the reduction in amplitude. Since in this case we are dealing with the BEST land-only temperatures, where the lag is short (less than a month on average) that means that the short-term sensitivity is about 64% of the longer-term sensitivity. This would make the longer-term sensitivity about 0.46°C per doubling of CO2. This is still far, far below the usual estimate of 3°C per doubling.

 

Advertisements

  Subscribe  
newest oldest most voted
Notify of

Not concluded reading the post yet Willis but looking forward to it as i do with many of your posts. The early thing that struck me was Mosher not forthcoming with information? That seems odd given his proclivity for hounding others for data.
( as usual my full name available privately if required by anyone, I prefer a nickname, it’s been with me a looong time.)

Ed

“This equates to a climate sensitivity of about 0.3°C per doubling of CO2 (0.8°C/W/m2 times 3.7 W/m2/doubling = 0.3°C/doubling)… which is a tenth of the canonical figure of three degrees per doubling of CO2.”
Isn’t 0.8 x 3.7 almost exactly 3.0, rather than 0.3?
[My bad, should be 0.08, fixed. -w.]

Venter

Excellent post Willis. Makes more sense compared to the faffling Mosh and Co have done.

Jim

Letenus me throw another wrinkle, the cleaning of the atmosphere. Eruption introduces the dust, cosmic rays, or whatever create a moisture path, which moves with the wind, collecting the upper atmosphere dust, precipitating to the ground, reinforcing the hydraulic cycle, which is why a cold planet like mars, a hot planet like venus do not have many clouds like ours or too many clouds traping the heat into a runaway situation.

MangoChutney

AFAIK climate sensitivity studies using observational evidence, not relying on climate models or paleoclimatic reconstructions, all show climate sensitivity to be low i.e. below 1C – 1.5C per doubling. All studies using climate models and paleoclimatic reconstructions show high climate sensitivity.
And isn’t climate sensitivity what this whole argument boils (oops) down to?
Makes me wonder why the IPCC prefer models and paleoclimatic reconstructions.

Willis you write “I’ve argued in a variety of posts that the usual canonical estimate of climate sensitivity, which is 3°C of warming for a doubling of CO2, is an order of magnitude too large.”
Could I suggest this ought to read “I’ve argued in a variety of posts that the usual canonical estimate of climate sensitivity, which is 3°C of warming for a doubling of CO2, is AT LEAST an order of magnitude too large.`
My capitals.

JCrew

common sense – (technobabbel/1) = common sense

The conclusions as to forcings depends on belief in the GHG theory which is questionable at the best of times. Temperature accuracy is also questionable and not the best metric of climate because water content of the atmosphere at the point of measurement is ignored but vital is calculating heat available which is the real driver of weather/climate. But heat content has no relationship to atmospheric CO2 content but to solar insolation at the time.

Volcanic eruptions are more a proxy than a cause of any significant climatic changes beyond a year or two.
http://www.vukcevic.talktalk.net/Ap-VI.htm
Ignore or take a note makes no difference to the climate, but it might help to the understanding.

Possibility 5. Eschenbach’s methods are unfit for purpose (not for the first time).
Volcanic forcings are of short duration so the climate system, especially the oceans, does not reach equilibrium. Therefore, dividing the temperature change by the forcing is guaranteed to underestimate sensitivity.

Paul S

Willis,
Firstly, I think you mean ‘0.08’ rather than ‘0.8°C per W/m2’.
Secondly, you’re missing the different timescales involved in CO2 versus volcanic forcing. Volcanic forcing is near-instantaneous, and is followed up a couple of years later with a quick forcing increase as aerosols are scrubbed. Conversely, CO2 has been accumulating gradually, with a persistent forcing in the same direction over the ~200 year period.
The best comparison to use for applying some form of check on your hypothesis are model outputs from 2xCO2 instantaneous forcing scenarios. There’s one in Climate Explorer for the GISS-EH model. I’ve produced output files for the land and land+ocean data (I don’t know how long these files stay on their servers, but you can output new ones yourself). If you look at these files, 10 years after a ~4W/m^2 forcing there is about 0.5ºC temperature increase (land, ~0.25ºC land+ocean) despite the fact that its ECS is 2.7ºC.

chris y

Willis-
There is a typo here- “The change in temperature is just under a tenth of the change in forcing (0.8°C per W/m2).”
Should be 0.08 C per W/m^2, no?
The same typo also appears here- “This equates to a climate sensitivity of about 0.3°C per doubling of CO2 (0.8°C/W/m2 times 3.7 W/m2/doubling = 0.3°C/doubling)…”
Should be 0.08C/W/m2.
Also, the GISS forcing of just under 3 W/m^2 at peak for Pinatubo is anomalously small when compared with the measured change in optical opacity of the atmosphere which peaked at 0.15 in the visible, giving a negative forcing of about 35 W/m^2 at peak, or ten times larger than what GISS climate models expectorate.

Jose

This equates to a climate sensitivity of about 0.3°C per doubling of CO2 (0.8°C/W/m2 times 3.7 W/m2/doubling = 0.3°C/doubling)… which is a tenth of the canonical figure of three degrees per doubling of CO2.

Last time I checked, 0.8×3.7 was 2.96.
Two little questions for you. First, how long do volcanic aerosols persist in the atmosphere, typically? And second, how long, all else being equal, would the atmosphere take to reach an equilibrium response to the aerosol forcing?
Oh, and one more if you would – roughly how many scientific papers which make estimates of the climate sensitivity have you read?

Willis: In your past posts about volcanoes, have you looked at the response of Land+Sea Surface Temperature data, like GISS LOTI, to the Mount Pinatubo eruption? If so, what was the maximum initial temperature drop that you found for it?

Roy UK

hmmm, don’t worry Willis, Mosher will be along real soon with a cryptic clue as to where you went wrong. I am sure his cryptic clues will be enough to satisfy everyone that BEST are doing their best.
Personally I think you are doing better than BEST.

JJ

Well, you can hit someone with the same strength, but depending where, how and with what you hit him, the pain can be quite different….
This simplistic comparison between the temperature response to a doubling of co2 or a volcanic eruption just doesn’t make a lot of sense.

The “canonical” estimate does not come from the Vatican, sole source of authorized canon, after lengthy conciles!
Let’s see how your finding correlates with model calculation.
So far models go like this:
– for any doubling of CO2 the forcing will be ΔF = 5.35 · ln(C/Co) = 5.35 · ln(2) = 3.7 W m-2. This is a physical spectrometric finding, not related to climate. Not too much to be discussed here.
– responding to such a forcing, and looking for a equilibrated energy balance, the primary temperature increase shoud be approx. 0.8°C. Other global models may offer little differences (before any feedback consideration). Regional variations may be larger in some places (e.g. Northern hemisphere) and smaller somewhere else.
– taking into account an overall negative feedback of -1.3 W m-2 K-1 from all known mechanisms (Planck, water vapour, lapse rate, albedo, and clouds. See: http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3819.1) this temperature response is reduced by half to approx. 0.6°C.
Neo-Vatican: IPCC’s basic feedback assumption is that an overall negative feedback of -1.3 W m-2 K-1 will provoke a positive temperature increase of 3.7/1.3 = 2.85 °C. This is dimensionally OK, but an absolute physical non-sense: negative feedback provoking positive reinforcment, infinitely small feedback with infinitely high system response. This was never discussed nor criticized in any paper, but blessed by the IPCC report committee, presided by authors of this non-sense.
This means that any temperature increase that would surpass 0.6°C would probably be due to other [non anthropogenic] factors than doubling CO2 atmospheric concentration by human made emissions.
And please note that we are far from doubling: we are at approx. 395 ppm as compared to historical pre-industrial 280 ppm (if we accept this baseline), just a 41% increase. So we speak here of approx. 0.4°C temperature increase attributable to CO2 emissions since two centuries.
Willis: your findings, taken out of temperature records statistics, is 0.3°C for any doubling. This would mean that homeostatic mechanisms are stronger than assumed in the underlying feedback paper wher a wide uncertainty range is also given.
Anyway, it’s difficult to establish a therory based on experimental work since we have only one Earth and one experiment. Let’s remain in conjectures.

highflight56433

John Marshall says:
August 13, 2012 at 6:53 am
The conclusions as to forcings depends on belief in the GHG theory which is questionable at the best of times.
How much heat could atmospheric CO2 possibly impart on the oceans compared to other factors: For instance a hundred year increase in solar activity compared to total atmosphere density and composition changes?
What about local CO2 concentrations? In a closed system, where CO2 is suggested to have such a dynamic effect on temperature, then a greenhouse with 1200 ppm parked next to a greenhouse with 120 ppm should demonstrated a very significant temperature difference.

Bill Yarber

Willis, always enjoy your enlightening and easily followed posts. Anyone who has been trained in or exposed to process control theory knows that a system dominated by positive feedbacks will saturate at one extreme or the other until affected by a dominant outside forcing! Earth has experienced at least two periods or near total glacial encapsulazation – 600 m & 2.4 b years ago. However, there is no indication that the Earth has even been more than 7C warmer than today. The obvious conclusion is that Earth’s climate is dominated by negative feedback that are periodically and also sporadically overridden by external forcings. Melankovich cycles are an obvious such external forcing. Sun spot cycles plus Dalton, Maunder et al minima are more frequent perturbations to Earth’s climate. Contiental drift and location near the equator is another long cycle forcing.
CO2 concentrations are estimated to have reached 7,000 ppm (4 doublings from today’s 400 ppm) but we have no evidence of runaway warming. CO2 and GHG’s may have a small impact, but trivial at best. I, therefore, agree with your estimate of 0.3C/doubling at MOST!
I’m very disappointed that process control engineers and professors around the world have not raised their voices in protest of this absurd AGW movement!
Bill

timetochooseagain

The likely reason why the apparent sensitivity for the long term change is large is because it’s land temps, rather than global surface temps. The change is very likely larger.
BTW Willis, surely .8/W/m^2 should be .08, other wise the change is almost exactly 3 C per doubling-which is again, even if correct, not the right answer due to completely excluding the ocean. There is a lot that’s wrong with the BEST “attribution”-the linear regression approach completely ignores physics and gives inconsistent answers.

BillC

Echo chamber criticisms and affirmations aside, thanks for doing this. Paul S’s comment above is cogent – and I suspect if you followed it through, you’d get a number for sensitivity >0.3. However, I’ll guess it will also be a lot less than 3.0. Take odds?

“The choice of two-years was motivated by maximizing the fit, and is considerably longer than the 4-8 month half-life observed for sulfate total mass in the atmosphere”
This is all about forcing the data to fit the theory – the exact OPPOSITE of science, but the also the EXACT rationalization of theology.
In other words, “We know what we know and we will not be confused by the facts.”

John Blake

Degree of “forcing” is indeed a critical factor in any self-dealing Warmist model. Alas, facts to hyper-politicized propagandists are immaterial. What might yet resolve this issue to mutually impartial, objective, rational satisfaction? Given the wholly qualitative nature of Warmists’ meretricious reliance on non-empirical data, we fear the answer is: Nothing.

Robbie

“Me, I go for door number four, small climate sensitivity. I say the climate is buffered by a variety of homeostatic mechanisms that tend to minimize the temperature effects of changes in the forcing, as I have discussed at length in a variety of posts.”
Could you also present us the links of the “variety of posts” so we can verify them ourselves please?

Willis Eschenbach

richard telford says:
August 13, 2012 at 6:57 am

Possibility 5. Eschenbach’s methods are unfit for purpose (not for the first time).
Volcanic forcings are of short duration so the climate system, especially the oceans, does not reach equilibrium. Therefore, dividing the temperature change by the forcing is guaranteed to underestimate sensitivity.

Gosh, telford, do you work at being snide, or is it just your natural state of being?
Number 5 is always a possibility … but in this case you haven’t thought the question all the way through. As I showed in “Time Lags in the Climate System“, in a system that is driven cyclically, the instantaneous sensitivity is related to the longer-term sensitivity by the relationship

where t1 is the lag, t is the length of the cycle, and s2/s1 is the size of the reduction in amplitude. Since in this case we are dealing with the BEST land-only temperatures, where the lag is short (less than a month on average) that means that the short-term sensitivity is about 64% of the final sensitivity. This would make the final sensitivity about 0.46°C per doubling of CO2.
w.

Willis Eschenbach

Michel says:
August 13, 2012 at 7:43 am

The “canonical” estimate does not come from the Vatican, sole source of authorized canon, after lengthy conciles!

Merriam-Webster: canonical 2. conforming to a general rule or acceptable procedure : orthodox
w.

Jim G

Michel says:
August 13, 2012 at 7:43 am
“The “canonical” estimate does not come from the Vatican, sole source of authorized canon, after lengthy conciles!”
Only pronouncements regarding Church dogma, such as the Trinity, are considered infallible as they are inspired by the Holy Spirit. When these are announced the Pope uses the term “WE” referring to himself and the Holy Spirit. Perhaps the IPCC is also conferring with the Holy Spirit prior to their pronouncements.

Willis Eschenbach

Robbie says:
August 13, 2012 at 10:08 am

“Me, I go for door number four, small climate sensitivity. I say the climate is buffered by a variety of homeostatic mechanisms that tend to minimize the temperature effects of changes in the forcing, as I have discussed at length in a variety of posts.”

Could you also present us the links of the “variety of posts” so we can verify them ourselves please?

Thanks, Robbie, be glad to. I finished writing the head post at 3:40 AM this morning, so I couldn’t be bothered hunting down the links at the time.
You might start with “The Thunderstorm Hypothesis“. Then take a look at “It’s Not About Feedback“, and “The Details Are In The Devil“. Follow that up with “Further Evidence for my Thunderstorm Thermostat Hypothesis“. For a chaser, try a look at yet another homeostatic mechanism in “Argo and the Ocean Temperature Maximum“.
That’s not an exhaustive list, I have more for when you finish those …
w.

Robbie, you asked for it. Enjoy your reading assignment, it should keep you busy for a few hours at least.☺

highflight56433

..speaking of Biblical faith driven belief.. Noah had a very competant weather forecaster. Maybe the CAGW crowd should look to some other faith for inspiriation. They obviously do not practice their current faith other than passing the plate.

Bill Illis

Just a personal comment, but is there someway to do away with the endless spelling mistake and typographical comments.
If one wants to disrupt a comment blog these days, the simplest way is to point out small typos and then re-comment on the same typos that someone else commented on earlier. And just keep doing that over and over.
At RealClimate, each individual could get in maybe 10 comments like this on each thread.

John Daly used 6 different methods to calculate climate sensitivity.
The average warming predicted by the six methods for a doubling of CO2, is only +0.2 degC.
http://www.john-daly.com/miniwarm.htm
So your 0.3C for a doubling of CO2 is right in line with his estimates.
And I am sceptical of the effects of the Laki eruption. Laki was an effusive eruption and unlike Plinian eruptions didn’t inject sulphates into the stratosphere. Which says to me, either the standard explanation of volcanic cooling from stratospheric sulphate aerosols is wrong or BEST’s cooling from the Laki eruption is fictional.
http://www.agu.org/pubs/crossref/2012/2011GL050075.shtml
Outstanding work, BTW.

jorgekafkazar

Michel says: “The “canonical” estimate does not come from the Vatican, sole source of authorized canon, after lengthy conciles!”
I believe it’s also mandatory to wear funny hats to issue canonical works. Here’s just one such bit of headgear:
http://i2.listal.com/image/892019/936full-jeremy-brett.jpg

Snowlover123

Willis, a fantastic and excellent post showing once again, that observations show a much more insensitive climate system than what is depicted by models. The power of a forcing to make the temperature rise One Degree C is 12.5 w/m^2 in the sensitivity that you calculated, making this considerably higher value than Spencer and Lindzen’s estimates of Climate Sensitivity (around 5-7w/m^2 for a Degree C of warming, which would still represent large negative feedback). This would represent about a 0.13 Degree C anthropogenic contribution to the 20th Century Warming at equilibrium, assuming that the IPCC’s net radiative forcing for all Anthropogenic sources combined is right (about 1.6 w/m^2). This is not nearly enough to explain the warming over the 20th Century.

HankHenry

“climate is buffered by a variety of homeostatic mechanisms that tend to minimize the temperature effects of changes in the forcing”
Dude, that’s the long winded way of saying Gaia. Awesome, I knew it all along. Mother Nature lives! Attempting straightforward models of the climate is a fools errand.

Bill Illis

I’ve overlayed the Dalton Minimum solar cycle TSI numbers (from Kopp and Lean 2011) onto the notorious 1775 to 1825 cold period.
Also shown is the exact date of the three major volcanoes and Berkeley Earth’s temperature numbers over the period.
There is a small effect from the volcanoes but looking at the high-resolution data makes it clear that the volcanic forcing attribution is way overblown. Temperatures went up after the 1809 unidentified eruption.
I would be tempted to conclude the solar cycle is responsible for the low temperatures in the period. There wasn’t much of solar cycle in terms of TSI changes in the Dalton Minimum.
http://s12.postimage.org/7mrm9mzf1/Berkeley_1775_to_1825.png

You might be dealing with land only temperatures, but I hope don’t imagine that land temperatures are independent of ocean temperatures. Any idea that the oceans have a lag of less than a month would be pretty crazy. Nevertheless, I have complete confidence that you will be able to conceive an analysis that will return an ocean lag this short.

rogerknights

Then take a look at “It’s Not About Feedback“, and “The Details Are In The Devil“.

The devil is in the pudding!

mycroft

As been alluded to in a previous post ..how do know that all eruptions have injected suplhates in to the atmosphere.?

Alexander K

Thanks once again, Willis.

Svend Ferdinandsen

I wonder if the differences are in the feedbacks. Maybe they don’t consider the volcanoes contribution gives feedback with water vapour, whereas CO2 creates feedback from water vapour. Or is it the other way around.

Dr Burns

Willis,
I’d be interested in your comments on John Daly’s methods, please ?
http://www.john-daly.com/miniwarm.htm
They seem very simplistic but support your conclusions.

HR

Willis on your possibilities.
This looks like an important reference for the NASA volcano forcing
http://arxiv.org/ftp/arxiv/papers/1105/1105.1140.pdf
(see section 12.3. Stratospheric aerosol forcing page 25)
In that sect hansen writes
“The ability of radiation calculations to simulate the effect of stratospheric aerosols on
reflected solar and emitted thermal spectra was tested (Fig. 11 of Hansen et al., 2005) using
Earth’s measured radiation balance (Wong et al., 2005) following the 1991 Pinatubo eruption.
Good agreement was found with the observed temporal response of solar and thermal radiation,
but the observed net radiation change was about 25 percent smaller than calculated. Because of
uncertainties in measured radiation anomalies and aerosol properties, that difference is not large
enough to define any change to the stratospheric aerosol forcing. ”
So a four fold difference between observation and theory isn’t enough to cause a hiccup. You maybe a bit too generous when you write “We might be wrong by a factor of two, but not by a factor of ten.”

Henry Clark

If the estimate of 0.46 degrees Celsius for a doubling of CO2 was combined with the assumption of 3.7 W/m^2 from that, then the result would be 0.12 K/W*m^2 climate sensitivity.
(Climate sensitivity then would be around 0.08 K/W*m^2 short-term and around 0.12 K/W*m^2 long-term).
Such could be about right. Dr. Idso estimated climate sensitivity by several different means in a paper; some appeared doubtful, but others seemed good. He got a figure which was similar (IIRC, 0.11 K/W*m^2 and 0.4 degrees Celsius for a CO2 doubling, although that is from memory and not double-checked).
It is less than Dr. Shaviv’s estimates, but, as much as I respect and applaud his work, his solar+GCR-based estimates have the weakness of being without attempting to take into account other factors such as ocean cycles at the same time as reconstructing temperature data without the CAGW movement’s fudging of it (with doing all at once being a difficult lengthy task which absolutely nobody has ever even seriously attempted as far as I’ve seen amongst many papers).
Such would mean the cosmic ray flux difference between the Little Ice Age and now ought to be really large, but that is conceivable enough, like Be-10 data illustrates ( http://www.freeimagehosting.net/newuploads/319xq.jpg ).
**********************
On the other hand, BEST is a fudged and false dataset overall, managed by an activist who briefly faked being a skeptic (with utter contradiction between figure 1 and the pre-fudging graphs illustrated in my August 9, 2012 2:26 pm and other comments in http://wattsupwiththat.com/2012/08/06/nasas-james-hansens-big-cherry-pick/#comments ). On yet the other hand, though, usually the standard procedure for fudging is spreading it out gradually over long periods of time, so such as relative figures from just one year to the next may be relatively close enough to accurate in themselves for the volcano analysis (with most year-to-year inaccuracy being far less than cumulative inaccuracy over decades).

If I understand it correctly, the BEST paper uses the data in a straight curve fitting exercise and doesn’t test the regression by using some of the data as a calibration period and then extrapolating to a training period for which we have historical data to compare against to see if their assumptions work. (they don’t).
This is an abysmal FAIL. It is not how SCIENCE is conducted.

phlogiston

Richard Telford
“Equilibrium”? What are you talking about? Equilibrium is practically never reached in the climate system – if it were then winds and ocean currents would cease, a nightmare scenario.
As a far-from-equilibrium system the climate displays nonlinear-nonequilibrium (quasi chaotic) dynamics, making simplistic linear estimates of sensitivity inappropriate. Please read Bill Yarber’s post on feedbacks from the control engineering perspective. The role and effects of feedbacks are quite different in a nonequilibrium nonlinear pattern system impacting primarily oscillation rather than sensitivity. The platinum-catalysed oxidation of CO is a classic experimental system to see this at work. An important characteristic of such systems is Lyapunov stability resulting in – as Willis concludes – limited and damped response to external forcings.

Watched the “day after tomorrow” yesterday on return from holiday. Realised that this would be the way future generations would see the climate hysteria of the naughties. In other words, they are going to believe we all thought … global warming was going to cause an ice-age.
Future generations are going to look at ours with the same incredulity of … “flat-earthers” (which is itself a false view of what people believed in the past) or of King Canute (who was trying to make a point that his advisers were wrong and humans couldn’t command nature … which is kind of apt),
We are going to look absolutely daft. Not only is global warming going to turn out to be almost completely false but the logic of the doomsday scenario will be that portrayed by holywood in the day after tomorrow, and not what any climate academic tried to say.

Joachim Seifert

willis, the Berkeley graph shows 7 eruptions since 1750 with one Laki,
see one comment, did not reach the stratosphere…The next, the GISS
graph shows 10 volcano eruption spikes downward since 1880…….
Now, where are all those many other eruptions, in particularly those, in
which there is NO spike downward but with a temp spike upward? Eruptions
which occurred in the midst of a decade with temp increase?
There are a good many more major eruptions not mentioned…..JS

Willis Eschenbach

mycroft says:
August 13, 2012 at 1:07 pm

As been alluded to in a previous post ..how do know that all eruptions have injected suplhates in to the atmosphere.?

Each eruption is different, as different as the composition of the underlying geology, as different as the size and nature of the eruptions. Some inject sulfur into the stratosphere, where it is carried around the globe, and some don’t.
We know who is who by analyzing the ice cores for the presents of sulfates. When sulfur is injected into the stratosphere, it eventually falls out all over the planet, including near the poles where it is captured and preserved in the ice cores. The timing and amount of that sulfate deposition is then used to back-calculate the amount that was injected into the stratosphere.
This is all explained, at least to some degree, in the paper cited in the BEST study.
w.

Willis Eschenbach

chris y says:
August 13, 2012 at 7:11 am

… Also, the GISS forcing of just under 3 W/m^2 at peak for Pinatubo is anomalously small when compared with the measured change in optical opacity of the atmosphere which peaked at 0.15 in the visible, giving a negative forcing of about 35 W/m^2 at peak, or ten times larger than what GISS climate models expectorate.

Thanks, Chris. You need to consider the distribution of the particles, and to do that you need a global distribution of measurements … or faith in climate models, which for this simple analysis (diffusion from a point source) might be adequate. I suspect the difference between your figure and theirs relates to that.
w.