Yesterday, the Daily Mail of the UK published a predictably inaccurate article entitled “Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995”.
The title itself is a distortion of what Jones actually said in an interview with the BBC. What Jones actually said is that, while the globe has nominally warmed since 1995, it is difficult to establish the statistical significance of that warming given the short nature of the time interval (1995-present) involved. The warming trend consequently doesn’t quite achieve statistical significance. But it is extremely difficult to establish a statistically significant trend over a time interval as short as 15 years–a point we have made countless times at RealClimate. It is also worth noting that the CRU record indicates slightly less warming than other global temperature estimates such as the GISS record.
The article also incorrectly equates instrumental surface temperature data that Jones and CRU have assembled to estimate the modern surface temperature trends with paleoclimate data used to estimate temperatures in past centuries, falsely asserting that the former “has been used to produce the ‘hockey stick graph’”.
Finally, the article intentionally distorts comments that Jones made about the so-called “Medieval Warm Period”. Jones stated in his BBC interview that “There is much debate over whether the Medieval Warm Period was global in extent or not. The MWP is most clearly expressed in parts of North America, the North Atlantic and Europe and parts of Asia” and that “For it to be global in extent, the MWP would need to be seen clearly in more records from the tropical regions and the Southern hemisphere. There are very few palaeoclimatic records for these latter two regions.”
These are statements with which we entirely agree, and they are moreover fully consistent with the conclusions of the most recent IPCC report, and the numerous peer-reviewed publications on this issue since. Those conclusions are that recent Northern Hemisphere warming is likely unprecedented in at least a millennium (at least 1300 years, in fact), and that evidence in the Southern Hemisphere is currently too sparse for confident conclusions. Mann et al in fact drew those same conclusions in their most recent work on this problem (PNAS, 2008).
Unfortunately, these kinds of distortions are all too common in the press nowadays and so we must all be prepared to respond to those journalists and editors who confuse the public with such inaccuracies.
Update 2/16/10. Phil Jones has confirmed to us that our interpretations of his comments in the BBC interview are indeed the correct ones, and that he agrees with the statements in our piece above. He and his CRU colleagues have also put up an response to some of the false allegations in a previous piece in the UK Guardian. We’ll report further such developments as they happen.
t_p_Hamilton, Reur 448
Sorry if my 446 was too complicated for you, but you are really asking the wrong question. (an indirect or obscure question)
Reur 451, it wasn’t complicated, it was vague.
BobFJ (450) — See
http://tamino.wordpress.com/2009/08/17/not-computer-models/
and
https://www.realclimate.org/index.php/archives/2010/02/whatevergate/comment-page-23/#comment-164509
which simplifies even further. These conceeptual models are based on the physics but certainly do no attempt to include everything.
BobFJ says “Everyone to their own perceptions of irony, but I find it amusing that you have emphatically contradicted, (denied?), the data such as in the following:”
My, but what a creative interpretation. How are dem cherries?
David B Benson Reur 453:
The Tamino article “Volcanic lull”, is the one under discussion, and there is no value in you adding distractions by citing two other Tamino articles. “Volcanic Lull” that you said you were interested in discussing in your 437/p9 does not fit your new “conceptual model” descriptions in 453 because amongst other things it attempts to make a fit with GISS temperature data. This is irrational at least because:
1) Fig 1 is strongly contradicted by Mauna Loa data. (where it is available from 1958)
2) There is no indication of where Tamino obtained his data in Fig 1
3) Tamino only considers “volcanic forcing” plus CO2, yet attempts to show a fit with GISS temperatures with bad data.
4) Some sources have attributed sulphate emissions reductions in Europe and USA to have had a significant effect.
5) Some sources have attributed ENSO etc to have had a significant effect.
6) Tamino’s exclusion of 4) & 5) invalidates any claim to have found a fit with GISS temperatures
Will you respond to these problems? (See also my 450/p9)
BobFJ,
The Mauna Loa data are not relevant to volcanic forcing–the altitude is not high enough. The volcanic forcing Tamino uses is standard. If you don’t like it, perhaps you could propose another time series?
Tamino has looked at ENSO (and volcanism) elsewhere (in December).
http://tamino.wordpress.com/2009/12/31/exogenous-factors/
Oh, look, exactly what you’d expect.
OK, Bob, repeat after me: It’s a model. You use it to look at whether a particular forcing is important. Tamino’s goal was to show volcanism was part of the answer for 1910-1940 (and did so long before Jones was asked the question).
Ray Ladbury Reur 454:
[1] You have also advised me that I should not rely on historical records, (incl photos etc), but should check out the statistics. The only relevant data I can think of that goes back a good way is the Oz BOM rainfall record which I would have thought is a good indicator. It clearly shows regional variations but with mostly much drier conditions for the whole ~45 years following 1900. (the start of records).
Where there some other statistics that you had in mind that I should check?
[2] I believe the cherry harvest in Victoria was good again this year. What was your point?
BobFJ (455) — Obviously you didn’t bother to look at the links I provided. I know this because the second is to a comment of mine, not Tamino’s. I suggest studying both rather closely; the latter uses decadal averages, in effect removing ENSO and solar cycles. Now just using CO2 forcing, R^2=0.96. With AMO added, R^2=0.99. By definition, essentially, whatever secular trens in various forcings do not contribute to the linear trend in North Atlantic SSTs then show up in AMO; volcano emissions, inductrial emissions, etc.
The general idea is to use conceptual and consitutive models to obtain some understanding of the importance of various forcings; CO2 is the vast majority of the net forcing:
http://bartonpaullevenson.com/Correlation.html
Ray Ladbury Reur 456:
[1] Now that IS a surprise! I was actually wondering if DBB might respond with “it is too high at over 3,000m”, given that quite a lot of the Earth’s surface is at or near sea level. The response to volcanic emissions, no matter what their altitude, is instantaneous at the surface in terms of reduced insolation. (This effect can be compared with shadow, seen whenever any object passes in front of the sun). My understanding is that the heavier particulates, (e.g. dusts, depending on type of eruption), may descend to the surface relatively rapidly, grading off to towards the aerosols that may be suspended for up to about 3 or 4 years. Thus, it would be better to have observations near the surface. Another difficulty is that rapid descent of dusts may not result in their global mixing or proper local detection.
[2] Out of curiosity, I Googled ‘standard volcanic forcing’, but couldn’t find anything. Do you know where Tamino gets his standard forcing from? Whatever, I don’t like it because Mauna Loa shows only two large down-spikes after 1960, whereas Tamino gives three of a different shape/distribution. BTW, Tamino does not label the events, whereas ML does. I cannot “propose another time series”, can you?
[3] This is not the article that you cited, and that we are discussing. I had a quick look to see if your new distraction carried the usual Tamino invective, and it does, so I didn’t read it.
[4] OK Ray, repeat after me: It is very naughty to make a conceptual model with apparently wrong data and significant missing parameters and then use it to show a fit with surface temperature data.
[5] So, when you wrote in 416: “Sulfates were lower in the 1910-1940 period due to abnormally low volcanic activity…”, did you mean to say something like:
Tamino’s model consequences for two large eruptions ~1885 & ~1905 were part of the answer for the 1910-1940 warming?
Ray Labury, further my 459
I forgot to ask, but since you assert that Mauna Loa has insufficient altitude to determine “volcanic forcing” effects, and you say that Tamino uses “standard volcanic forcing” way back to 1880, at what altitude was it determined; how; and by whom?
BobFJ,
Most aerosols in the troposphere are going to rain out pretty rapidly. It’s the stratospheric aerosols that have the dimming effect.
Bob, you clearly haven’t done much modeling. You model a phenomenon to elucidate what the contribution of its factors might be. In most physical models, you don’t have so much interaction between parameters that simplification invalidates the results. In ecology, this is, of course, not always the case.
David B. Benson Reur 458:
Sorry, but the reason I did not open yours was that the Tamino article starts with the word ‘Denialists’ and so on, and I rapidly lose patience with such stuff. I should have been more patient and looked at yours! Sorry.
Nevertheless, the issue that set this exchange off is about a Tamino article that Ray cited, which I submit, has substantial problems which are NOT just about modelling.
I guess it’s reasonable that other and more recent modelling is better than the modelling aspects in the original Tamino citation, but discussing such improvements would be a distraction.
You expressed an interest in seeing what the issues are in your 437, but I‘ve not yet fully covered them. This is one reason for avoiding such distractions.
BobFJ — Tamino used volcano forcings available from GISS. It is the case that IPCC AR4 seems to indicate substantial uncertainty with regard to such forcings. In any case, I now think that Tamino might have done even better to consider AMO,
http://www.aoml.noaa.gov/phod/d2m_shift/amo_fig.php
which includes volcano forcings along with other factors.
What I will defend as based on the physics is his two box model and despite the off-putting wording therein, the link I provided for you is worthy of attention.
BobFJ:
It appears that the graphs you are trying to compare measure entirely different things. One is net solar intensity, the other is global mean effective forcing (from stratospheric aerosols alone).
It disturbs me that you were unable to find the source for Tamino’s data, given that he provided the link to the actual GISS data right in the text, right above the graph. You had time to make a graph comparing apples to oranges, but you didn’t have time to read what Tamino wrote?
That’s a dangerous trap. Graphs alone don’t tell you everything. Read the discussion! And don’t make accusations when they are clearly baseless! If you are unsure why there is a difference, or you can’t find a source, ask politely instead of making wild and extravagant claims.
David B. Benson Reur 463:
Thanks for that David. I did actually look at the first GISS tabulation and noticed that the numbers were different to what was on Tamino’s graph, without realizing that the table was actually totally irrelevant. (thought it was another problem to look into!)
Perhaps after a glass of Cabernet-Merlot I’ll have a go with your recommendation, but to repeat, There are other apparent problems that I’ve not come to yet.
Ray Ladbury Reur 461:
Yes but; the Mauna Loa empirical data suggests that the lower level and some heavier stuff hangs around for a year or more and the upper aerosols up to about 4 years (per El Chichon & Pinatubo)
Yes, but I do understand what models are about, and my point is that the Tamino article that we are discussing cannot, amongst other things be properly applied to showing a fit to GISS temperatures. (e.g. missing inputs to the model)
Didactylos Reur 464 in part:
This is a quickie: I’m mystified why you qualify volcanic forcing: from stratospheric aerosols alone. For a start, how and why would tropospheric dimming be excluded, when the substantial down-spike of typically around a year is suggestive of the lower levels and can be measured from the surface?
The Tamino graph of volcanic forcing is in Watts/m^2. To get the same units on the ML graph, just take the percentage scale and multiply by the solar constant. Then subtract the down-blips from the background level. Of course the datums are different, but not a problem. A reduction in transmissivity is another way of expressing dimming either as a percentage or in w/m^2
End of my lunchbreak….. May return this evening
BobFJ,
Aerosol forcing is predominantly due to sulfate aerosols. These are reactive and precipitate out on a timescale of weeks to months.
As to Tamino’s analysis, you seem to have utterly misunderstood it. The GISS volcanic forcings are INPUT to the model. What Tamino shows is that you get a reasonable match to the temperature data if you take into account both the prompt (atmospheric) response and the slower (oceanic) response of the climate.
Methinks you would do well to spend more time trying to understand before you jump to conclusions.
Didactylos Reur little rant in the second part of your 464:
I’m sorry that I misunderstood the first GISS reference, which was irrelevant, and maybe as a result of that I skipped or missed the second GISS item. (See also my 465). BTW, I’ve noticed a few strange things in the latter tabulation, which I’ll study a bit more yet.
Meanwhile, comparing the Tamino graph with Mauna Loa:
The former is presumably based on estimated information and shows that the Agung eruption is of about the same forcing (dimming) magnitude as El Chichon, whereas Pinatubo is much greater in magnitude. However, the Mauna Loa empirical data shows the relative magnitudes of El Chichon and Pinatubo to be reversed. Also the ML empirical data for Agung is slight, whereas it is huge per GISS/Tamino. BTW, have you heard of Agung before? Not me, but the other two certainly yes!
http://www.iges.org/c20c/c20c_forcing/volc.html
“How to include volcanic forcing in C20C runs
The Hadley Centre has used an updated version of the time series of Sato et al. (1993), including the effects of Pinatubo …. The data are derived largely from optical depth measurements but also other data, obviously of varying quality & coverage but generally getting better with time.”
Not “estimated” data.
And not point source data.
You get results that depend on the location of the volcano _and_ the measuring stations.
This goes into it in considerable detail:
http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1203&tstamp=
Look at the distribution of Pinatubo’s aerosols.
http://img91.imageshack.us/img91/6100/pinatubo4web3ht.jpg
See why picking only Mauna Loa will give you a different chart than taking measurements globally? See why using just Mauna Loa gives you wrong numbers to _apply_ globally?
> BobFJ
> presumably
Incorrect presumption. You can look this stuff up for yourself.
Mauna Loa is often used as an illustration, e.g. here
http://www.climate.noaa.gov/images/about_climate/greenhouse_graph.jpg
illustrating this page:
http://www.climate.noaa.gov/index.jsp?pg=/about_climate/about_index.jsp&about=greenhouse
But as several people have pointed out, you don’t get information about the effect on global climate from just one source, not even that one. You might as well be picking just one thermometer location and be claiming you’re getting good information about the effect on climate.
That NOAA page, illustrated with the Mauna Loa graph, describes the actual monitoring instrument _network_ this way:
“Instruments and Measurements – In situ measurements of a variety of aerosol optical properties are made at GMD’s aerosol monitoring sites. The measurement suite enables calculation of direct aerosol climate forcing. The measured values relevant for climate forcing calculations are: light absorption, total scattering and backscattering. These measurements are used to derive parameters required in the forcing calculation.”
Here’s another example of the chart:
http://www.ec.gc.ca/scitech/2A953C90-CC12-42B2-BD0A-B51FECC2AEC3/C.8_e.jpg
And another:
http://www.ncdc.noaa.gov/paleo/globalwarming/images/forcing.jpg
Here’s the Pinatubo aerosol distribution in more detail, with caption:
http://earthobservatory.nasa.gov/Features/SAGEIII/Images/SAGEII_Pinatubo.jpg
and some additional explanation:
“… For example, the SAGE II satellite instrument, the predecessor to SAGE III launched in 1984, observed dispersal of volcanic aerosols following the massive eruption of Mt. Pinatubo in 1991. These measurements were crucial in linking a decline in the globally averaged surface temperature in mid-1992 of about 1 degree Fahrenheit to the large aerosol concentrations from the volcanic eruption. Aerosols from Mt. Pinatubo also strongly influenced the observed ozone trend—an effect that would not have been detected without measurements like those from SAGE II. The data provided unique insight into the complex flow of air in the stratosphere ….”
Key words: globally averaged.
Data, again, is taken from multiple stations, e.g.
http://resources.metapress.com/pdf-preview.axd?code=px672146l711w161&size=largest
http://www.springerlink.com/content/px672146l711w161/
“… Figure 1 gives a map showing the location of 53 actinometric stations of the Russian network … over Russia and to compare this pattern with that of the global aerosol distribution …”
Ray Ladbury Reur 468:
I’m not sure what your point is, but I come back to the observations made at Mauna Loa that show major dimming for a year or two, and then a tailing off of up to about 4 years
Obviously Tamino has input some global forcing numbers, which I’m trying to show, are a bit sus’.
[Response: Huh? The stratospheric aerosol history that we have developed is not ‘ a bit sus ‘ – what are you talking about? Please read the basic papers (i.e. Sato et al, 1993) to understand what this data is. – gavin]
He also inputs CO2, but he fails to include other parameters.
However obtaining a fit by using suspect data, (arguably more so back to 1880, and see below), and incomplete inputs, is hardly convincing. One might also get a fit with sales profits with McDonalds hamburgers. (more so with GISS; less so with HADCRUT)
Oh, and: Yes, I follow the argument of his “two-box” model but have some problems with it; some of which are given more background in Hanks comments, and, when I have time, my responses thereto. Incidentally, why not a three-box model? Surface air Temperature; land surface T, & SST
Hank Roberts, thanks for your series of comments. Good work! but I’m about to start my weekend, and I doubt if I‘ll have much time. At a quick flick through, I was impressed by this graphic of Pinatubo’s emissions, although it is not given if it was a snapshot in time or some average over a period.
http://img91.imageshack.us/img91/6100/pinatubo4web3ht.jpg
Last time I was in Hawaii, it was located in the tropical North Pacific, which places it in ideal location for observation of the recent three big eruptions. The graphic suggests that the greatest impact is in the tropics, which, as you know is “the heat engine of the world”
The big latitudinal variations in concentrations etc, suggest that it would be necessary to use time-series data in grids around the planet, with some very complex integrations to get a complete picture of global dimming and mixing by region. Thus the use of an alleged global average by Tamino puts his modelling into further questionability.
BobJF: I have to agree with Ray Ladbury – “Methinks you would do well to spend more time trying to understand before you jump to conclusions.”
BobFJ (473) — A more interesting three box model would be (1) air + top few meters of the ocean (2) shallow ocean (3) deep ocean. Tamino does the first two and the relaxation time for the third is so long that we can ignore it for such conceptual studies.
> BobFJ
> … presumably based on estimated information
> … suspect … alleged …
You’ve backpedaled from wrong presumption directly to insinuation.
You don’t even know whose work you’re calling ‘suspect’ — even though it’s been cited twice in the last few days and you’ve been given pointers and pictures.
> snapshot
I gave you a better source. You didn’t read even the caption on it, eh?
http://earthobservatory.nasa.gov/Features/SAGEIII/Images/SAGEII_Pinatubo.jpg
> my weekend, and I doubt if I’ll have much time
“What a piece of work ….” — Hamlet
BobFJ,
The volcanic forcings are standard. And as I say, Tamino has looked at volcanic + ENSO elsewhere. You would do well to peruse some of his analyses.
Re your 3 layer model: I don’t think land surface temperatures would add all that much. Heat flows pretty slowly in the solid Earth. However, if you were interested in pursuing this, you could look at borehole measurements.
Gavin, Reur response in my 473:
Whoops, sorry, you’re right, I should not have used such sloppy language, but rather the more scientifically correct substantial uncertainty.
[Response: Still not sure what you are talking about. Especially, compared to most of the forcings the stratospheric aerosols are pretty well characterised. I see no reason for any of your descriptions. – gavin]
Hank Roberts Reur Rant in 477:
Do you find it difficult to understand what I wrote as follows?
“… but I’m about to start my weekend, and I doubt if I‘ll have much time…”
Your stream of comments is beginning to look like that dialogue on the “close Encounters…” thread about the ability of your hand to identify infrared radiation. (as distinct from other heat sources)
Ray Ladbury, Reur 478:
Ray, we are discussing the Tamino article that you cited and supported. He and others may well have some improved models but they are distractions to the original. I think you would do well to peruse the uncertainties in volcanic forcings that have been expressed elsewhere, such as in the links given by Gavin above.
Here, Bob, another way to separate visible from infrared:
http://www.kruschwitz.com/Cold/hot.htm
BobFJ,
You seem to be afraid of uncertainty–as if having uncertainty in a forcing estimate invalidated it. The forcing Tamino used is a standard. The results he get show that the low number of volcanic eruptions in the 1900-1940 period likely contributed significantly to thewarming observed in that period. Now you can reject that analysis if you please, but no one is going to take you seriously unless a)you present an analysis showing deficiencies in what Tamino presented, or b)you present an analysis of your own showing the contrary. Until that time, as I said, you would do well to look at some of the analyses I and others have cited, because it is clear that you are arguing mainly against straw men of your own construction–and astoundingly, still losing.
Gavin, Reur response within my 479:
Well, I mean it in the context NOT of very recent times but of this Tamino graph , which he uses to create a model for the full period from 1880. Sure, obviously, the capabilities have been improving in recent satellite times, but uncertainties remain, according to your two links appended in my 473:
The first from NASA opens with:
“The dataset is updated when additional data or improvements become available. (Last Modified: on 2002′ 04′ 18) We welcome comments or suggestions regarding these data…”
And, within Sato et al, some brief extracts:
“…We describe the sources of our data and the reasons for choices among alternative sources. We would welcome information on any observations with potential for improving this data set…”
“…Although these uncertainties are large, [subjectively 50%, reducing to 25%], we believe that the estimated history of aerosol optical depth provides a useful measure of volcanic aerosol climate forcing for the past century..”
“…Therefore it is important to improve the accuracy with which the volcanic climate forcing is specified, to the extent that is practical…”
[Response: Sure. But the standard statements about how we should always strive to do better (which we should) and that accuracy degrades as you go back to the 19th C, doesn’t mean that there is ‘substantial uncertainty’ over the whole thing. If you want to discuss the impact of Krakatoa in 1883, sure – but the temperature data to check the response against is just as bad. – gavin]
Ray Ladbury Reur 483:
It may be the best estimate available, but Sato et al opine that the uncertainty is large, prior to 1990. Thus for Tamino to use this data and to exclude other relevant parameters, (without explanation or caveat), and then claim a fit with GISSTEMP, is an academic exercise with zero merit, and is likely to create misunderstanding.
Well, amongst other things, and keeping it simple, please study this composite graph , and explain why in the period 1940 to 1960 there was rapid cooling whilst low volcanic activity continued, as it did from ~1910 to 1940.
Hank Roberts Reur 482
This belongs over at the “Close Encounters…..” thread, if you would like to get people to shake their heads wondering why you keep citing stuff that is irrelevant to the debate.
Whilst you are there, perhaps check-out Doug Bostrom’s 972, and a gem from Jedda; 978.
BobFJ:
You seem to be trying to attribute all climate to volcanoes today. I thought we got past this idea that climate only has one driver? More than two drivers, as well.
Yes, that particular Tamino post only looked at volcanoes and greenhouse gases, but Tamino has hundreds of other posts, you know.
And your “without explanation or caveat” jibe is just low – and wrong. Tamino said explicitly: “This is of course a simplified model, which can’t be expected to be as realisitic as general circulation models.” As for explanation – the whole post is explanation!
Take your snark elsewhere, please.
> BobFJ
> irrelevant to the debate
You keep trying to make these conversations into debate — ‘debate’ about Tamino’s topics.
Education is furthered by asking open questions, doubting one’s own ideas, looking for more information. You can’t do those and win a debate.
You’re using your debating tactics to dismiss anyone who’s trying to learn. Debate isn’t learning. It’s arguing just one side instead of learning.
In your own mind perhaps you “win” — you’ve found a place you can keep posting your confusion about what’s explained at Tamino’s.
You’re making your confusion everyone else’s problem. Are you learning anything?
I think it is time to move-on to some issues with Tamino’s Fig 3. With reference to Fig 2, he then goes on to say:
“We note that there’s a large decrease early in the data. This is not necessarily reflective of an actual decrease, it’s because for the earliest few decades we’re estimating a 30-yr smooth based on considerably less than 30 yrs. of data. To approximate the 30-yr smooth with any accuracy, we should only use the data from about 1900 on, giving us 30-yr smoothed values based on at least 20 years of data. …”
So, why start the smoothed line at 1920? Should it not be 1895, enabling 15 years of data each side of that target year? (or, if he’s doing a PMA smoothing, (?!), should it not be 1930?
See this composite graph for more detail on this, and on several other questions that can be asked. For instance, between 1915 & 1960, the volcanic forcing is approximately zero, yet Tamino computes a continuous temperature rise well beyond his 30-year lull hypothesis.
BobFJ:
Are you posting all these criticisms of Tamino here because you have failed Tamino’s “stupid threshold”, and he no longer allows you to post at his site?
If not, why not address these questions to him directly? Although personally, I still believe all your questions are answered by actually reading what he wrote. Failure to understand something is no crime. Your accusatory tone, however, is just rude.
CORRECTION Re 489,
Sorry, 1920 should read 1900, 1895 should read 1885 and 1930 should read 1910, Thus in the last para:
So, why start the smoothed line at 1900? Should it not be 1885, enabling 15 years of data each side of that target year? (or, if he’s doing a PMA smoothing, (?!), should it not be 1910?
See this composite graph
for more detail on this, and on several other questions that can be asked. For instance, between 1915 & 1960, the volcanic forcing is approximately zero, yet Tamino computes a continuous temperature rise well beyond his 30-year lull hypothesis.
You’re eager to “move-on” — you were wrong to tell people that the data Tamino used–that he cited, with a link, in his original post– was
> … presumably based on estimated information
> … suspect … alleged …
You’ve been making up strawmen, pinning Tamino’s name to them, and attacking those, asking questions as though they hadn’t been answered in the thread:
were the forcings estimated/suspect/alleged? (No; links were provided)
“why start … at 1920” (explained right above the chart; to get 20 years);
warming continues past 30 years (due to other forcings; links provided).
If you managed to ask an interesting question, you’d get some response from the scientists. So far you don’t seem to be getting it.
Didactylos Reur 487:
Please note that my comment that you dislike was specific to stated facts, and I quote it with the original emphasis:
It [the GISS volcanic forcing] may be the best estimate available, but Sato et al opine that the uncertainty is large, prior to 1990. Thus for Tamino to use this data and to exclude other relevant parameters, (without explanation or caveat), and then claim a fit with GISSTEMP, is an academic exercise with zero merit, and is likely to create misunderstanding.
Didactylos Reur 490:
Well actually I did ask tamino as you and Hank have suggested, but it was deleted without comment. It was the only time I’ve commented there.
Hank Roberts Reur 492
1) I presumed volcanic forcing back to 1880 was estimated because it is obvious that good empirical observation would not have been possible.
2) What you may not realize is that time-series smoothing should use CMA or centred Moving Average methodology, so that in the case of a 30-year smoothing, for any target year, 15 years of data are needed before and after that point; not 20 years. On the other hand, if PMA was used, apart from the fact that it is unsuitable for time-series, 30 years Prior to the target point is required; not 20.
3) According to the text, Fig.3 is a 30-year smooth of volcanic forcings only, so you have not explained why the temperature continues to rise beyond the hypothetical 30-year lag of the only forcing portrayed.