Guest Post by Willis Eschenbach
In a recent interchange over at Joanne Nova’s always interesting blog, I’d said that the slow changes in the sun have little effect on temperature. Someone asked me, well, what about the cold temperatures during the Maunder and Dalton sunspot minima? And I thought … hey, what about them? I realized that like everyone else, up until now I’ve just accepted the idea of cold temperatures being a result of the solar minima as an article of faith … but I’d never actually looked at the data. And in any case, I thought, what temperature data would we have for the Maunder sunspot minimum, which lasted from 1645 to 1715? So … I went back to the original sources, which as always is a very interesting ride, and I learned a lot.
It turns out that this strong association of sunspot minima and temperature is a fairly recent development. Modern interest in the Maunder sunspot minimum was sparked by John Eddy’s 1976 publication of a paper in Science entitled “The Maunder Minimum”. In that paper, Eddy briefly discusses the question of the relationship between the Maunder sunspot minimum and the global temperature, viz:
The coincidence of Maunder’s “prolonged solar minimum” with the coldest excursion of the “Little Ice Age” has been noted by many who have looked at the possible relations between the sun and terrestrial climate (73). A lasting tree-ring anomaly which spans the same period has been cited as evidence of a concurrent drought in the American Southwest (68, 74). There is also a nearly 1 : 1 agreement in sense and time between major excursions in world temperature (as best they are known) and the earlier excursions of the envelope of solar behavior in the record of 14C, particularly when a 14C lag time is allowed for: the Sporer Minimum of the 16th century is coincident with the other severe temperature dip of the Little Ice Age, and the Grand Maximum coincides with the “medieval Climatic Optimum” of the 11th through 13th centuries (75, 76). These coincidences suggest a possible relationship between the overall envelope of the curve of solar activity and terrestrial climate in which the 11-year solar cycle may be effectively filtered out or simply unrelated to the problem. The mechanism of this solar effect on climate may be the simple one of ponderous long-term changes of small amount in the total radiative output of the sun, or solar constant. These long-term drifts in solar radiation may modulate the envelope of the solar cycle through the solar dynamo to produce the observed long-term trends in solar activity. The continuity, or phase, of the 11-year cycle would be independent of this slow, radiative change, but the amplitude could be controlled by it. According to this interpretation, the cyclic coming and going of sunspots would have little effect on the output of solar radiation, or presumably on weather, but the long-term envelope of sunspot activity carries the indelible signature of slow changes in solar radiation which surely affect our climate (77). [see paper for references]
Now, I have to confess, that all struck me as very weak, with more “suggest” and “maybe” and “could” than I prefer in my science. So I thought I’d look to see where he was getting the temperature data to support his claims. It turns out that he was basing his opinion of the temperature during the Maunder minimum on a climate index from H. H. Lamb, viz:
The Little Ice Age lasted roughly from 1430 to 1850 … if we take H. H. Lamb’s index of Paris London Winter Severity as a global indicator.
After some searching, I found the noted climatologist H. H. Lamb’s England winter severity index in his 1965 paper The Early Medieval Warm Epoch And Its Sequel. He doesn’t give the values for his index, but I digitized his graph. Here are Lamb’s results, showing the winter severity in England. Lower values mean more severe winters.
So let me pose you a small puzzle. Knowing that Eddy is basing his claims about a cold Maunder minimum on Lamb’s winter severity index … where in Lamb’s winter severity index would you say that we would find the Maunder and Dalton minima? …
Figure 1. H.H. Lamb’s index of winter severity in England.
As you can see, there is a reasonable variety in the severity of the winters in England. However, it is not immediately apparent just where in there we might find the Maunder and Dalton minima, although there are several clear possibilities. So to move the discussion along, let me reveal where they are:
Figure 2. As in Figure 1, but with the dates of the Maunder and Dalton minima added.
As we might expect, the Maunder minimum is the coldest part of the record. The Dalton minimum is also cold, but not as cold as the Maunder minimum, again as we’d expect. Both of them have warmer periods both before and after the minima, illustrating the effect of the sun on the … on the … hang on … hmmm, that doesn’t look right … let me check my figures …
…
…
…
… uh-oh
…
…
Well, imagine that. I forgot to divide by the square root of minus one, so I got the dates kinda mixed up, and I put both the Maunder and the Dalton 220 years early … here are the actual dates of the solar minima shown in Lamb’s winter severity index.
Figure 3. H.H. Lamb’s England winter severity index, 1100-1950, overlaid with the actual dates of the four solar minima ascribed to that period. Values are decadal averages 1100-1110,1110-1120, etc., and are centered on the decade.
As you can see …
• The cooling during the Wolf minimum is indistinguishable from the two immediately previous episodes of cooling, none of which get much below the overall average.
• The temperature during the Sporer minimum is warmer than the temperature before and after the minimum.
• The coldest and second coldest decades in the record were not associated with solar minima.
• The fastest cooling in the record, from the 1425 decade to the 1435 decade, also was not associated with a solar minimum.
• Contrary to what we’d expect, the Maunder minimum warmed from start to finish.
• The Dalton minimum is unremarkable in any manner other than being warmer than the decade before the start and the decade after the end of the minimum. Oh, and like the Maunder, it also warmed steadily over the period of the minimum.
Urk … that’s what Eddy based his claims on. Not impressed.
Let me digress with a bit of history. I began this solar expedition over a decade ago thinking, along with many others, that as they say, “It’s the sun, stupid!”. I, and many other people, took it as an unquestioned and unexamined “fact” that the small variations of the sun, both the 11-year cycles and the solar minima, had a discernible effect on the temperature. As a result, I spent endless hours investigating things like the barycentric movement of the sun. I went so far as to write a spreadsheet to calculate the barycentric movement for any period of history, and compared those results to the temperatures.
But the more I looked, the less I found. So I started looking at the various papers claiming that the 11-year cycle was visible in various climate datasets … still nothing. To date, I’ve written up and posted the results of my search for the 11-year cycle in global sea levels, the Central England Temperature record, sea surface temperatures, tropospheric temperatures, global surface temperatures, rainfall amounts, the Armagh Observatory temperatures, the Armagh Observatory daily temperature ranges, river flows, individual tidal stations, solar wind, the 10Beryllium ice core data, and some others I’ve forgotten … nothing.
Not one of them shows any significant 11-year cycle.
And now, for the first time I’m looking at temperature effects of the solar minima … and I’m in the same boat. The more I look, the less I find.
However, we do have some actual observational evidence for the time period of the most recent of the minima, the Dalton minimum, because the Berkeley Earth temperature record goes back to 1750. And while the record is fragmentary and based on a small number of stations, it’s the best we have, and it is likely quite good for comparison of nearby decades. In any case, here are those results:
Figure 4. The Berkeley Earth land temperature anomaly data, along with the Dalton minimum.
Once again, the data absolutely doesn’t support the idea of the sun ruling the temperature. IF the sun indeed caused the variations during the Dalton minimum, it first made the temperature rise, then fall, then rise again to where it started … sorry, but that doesn’t look anything like what we’d expect. For example, if the low spot around 1815 is caused by low solar input, then why does the temperature start rising then, and rise steadily until the end of the Dalton minimum, while the solar input is not rising at all?
So once again, I can’t find evidence to support the theory. As a result, I will throw the question open to the adherents of the theory … what, in your estimation, is the one best piece of temperature evidence that shows that the solar minima cause cold spells?
Now, a few caveats. First, I want to enlist your knowledge and wisdom in the search, so please just give me your one best shot. I’m not interested in someone dumping the results of a google search for “Maunder” on my desk. I want to know what YOU think is the very best evidence that solar minima cause global cooling.
Next, don’t bother saying “the Little Ice Age is the best evidence”. Yes, the Maunder occurred during the Little Ice Age (LIA). But the Lamb index says that the temperature warmed from the start of the Maunder until the end. Neither the Maunder’s location, which was quite late in the LIA, nor the warming Lamb shows from the start to the end of the Maunder, support the idea that the sun caused the LIA cooling.
Next, please don’t fall into the trap of considering climate model results as data. The problem, as I have shown in a number of posts, is that the global temperature outputs of the modern crop of climate models are nothing but linear transforms of their inputs. And since the models include solar variations among their inputs, those solar variations will indeed appear in the model outputs. If you think that is evidence for solar forcing of temperature … well, this is not the thread for you. So no climate model results, please.
So … what do you think is the one very best piece of evidence that the solar minima actually do affect the temperature, the evidence that you’d stand behind and defend?
My regards to you all,
w.
[UPDATE] In the comments, someone said that the Central England Temperature record shows the cooling effects of the solar minima … I’m not finding it:
As you can see, there is very little support for the “solar minima cause cool temperatures” hypothesis in the CET. Just as in the Lamb winter severity data and the Berkeley Earth data, during both the Dalton and Maunder minima we see the temperature WARMING for the last part of the solar minimum. IF the cause is in fact a solar slump … then why would the earth warm up while the sun is still slumping? And in particular, in the CET the Dalton minimum ends up quite a bit warmer than it started … how on earth does this support the “solar slump” claim, that at the end of the Dalton minimum it’s warmer than at the start?
The Usual Request: I know this almost never happens, but if you disagree with something that I or someone else has said, please have the common courtesy to QUOTE THEIR EXACT WORDS that you disagree with. This prevents much confusion and misunderstanding.
Data: Eddy’s paper, The Maunder Minimum
Lamb’s paper, The Early Medieval Warm Epoch And Its Sequel
Berkeley Earth, land temperature anomalies
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lsvalgaard
Whether not you understand that cosmic rays will be targeted in certain areas? Over the equator increase a little, but, for example, over northern Canada, much more. This is bad news for America.
http://oi61.tinypic.com/33avsdl.jpg
Salvatore Del Prete says:
June 24, 2014 at 10:30 am
Balance is so important especially in this crazy field.
No, balance is about opinions. Science is about data and facts [evidence in short]. On that there can be no balance.
Ulric Lyons says:
June 24, 2014 at 10:49 am
“Now you are claiming that CET is not a good measure for the global temperature.”
As we can see since 2010, it can be a poor measure in the short term.
Yet you use it for SC24, go figure.
“Some cases that you cite as a question are ambiguous (e.g. which work of Newton?) but in each case the Null Hypothesis was that the considered system did not experience a change unless there was evidence of a change. This must be true because it is a fundamental principle of empiricism; indeed, it leads to the assumption that the same physical laws exist throughout the universe.”
Wrong.
The null hypothesis as a tool was developed in 1935.
it is tool used in statistical testing.
When netwon postulated that F=MA he was doing science. There was no null
When Einstein formulated e=Mc^2 he was doing science. there was no null.
The null is a tool. it It is a historical development, not foundational. It is used in experiments, If the experimenter is a frequentist. Baysians need no stinking null.
But tell me? when the structure of DNA was postulated, where they doing science?
what was their null?
When foucault did early measurements of the speed of light was he doing science?
what was his null?
An observation based investigation into what scientists ACTUALLY DO, an empirical investigation of what scientists do, a scientific investigation of what they do, will show you this.
A null is not required. The null is a tool. its a tool used by ONE school of statistics. you can do science ( see newton, see ANYONE before 1935 ) without a null.
When Fischer defined what the null was did he argue that it was the foundation of science?
It’s simple. if the null were foundational then one could not do science without it.
When X rays were discovered, that was surely science. What null was specified before that discovery?
lsvalgaard says:
“Yet you use it for SC24, go figure.”
As I explained, not for global temp in the short term.
Ulric Lyons says:
June 24, 2014 at 11:56 am
As I explained, not for global temp in the short term.
For the Sun to be a major player in global climate, you should use global values. But perhaps you don’t think the Sun is important.
lsvalgaard
I do not know what you want to prove? That Thames has not frozen? Great Lakes is not frozen?
ren says:
June 24, 2014 at 12:00 pm
I do not know what you want to prove?
Why do you think I want to prove anything? Except that you have no clue.
“but in each case the Null Hypothesis was that the considered system did not experience a change unless there was evidence of a change.”
That’s not a null. That is a tautology.
If you want some reading on criticisms of using a null start here
http://polmeth.wustl.edu/media/Paper/gill99.pdf
The criticism go back to the very invention of the tool.
try Tukey.
http://forrest.psych.unc.edu/jones-tukey112399.html
or this
http://lesswrong.com/lw/g13/against_nhst/
or this
http://www.bayesian-inference.com/hypotheses
Maybe it’s strange to you because your theory of how science actually works is wrong.
Your theory. the null is foundational.
the observations: people do science all the time without a null.
when the data contradicts your theory, call dr feynman
I wonder why the Swedes during the Maunder Minimum they wandered south?
Steven Mosher says:
Did netwon do science?
what was his null
Did einstein do science?
what was his null.
They falsified a number of null hypotheses. Newton falsified infinitesimals, etc.
The Null Hypothesis is a tool. A very powerful tool. The Null Hypothesis falsifies the cAGW conjecture.
I understand why believers in the “carbon” scare hate the Null Hypothesis, and that they try to denigrate it in any possible way. But unless it can be falsified, it is showing us that AGW makes no measurable difference in global temperature.
I understand that steps on a lot of toes. But, there it is.
Great paper on the devastation following the 1257-58 eruption.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB8QFjAA&url=http%3A%2F%2Fjrscience.wcp.muohio.edu%2Fclimatepdfs02%2Fclimimpts1258volcaclimchg00.pdf&ei=VsmpU866AZCiyASAhIKoDA&usg=AFQjCNHLGf3IVaNVvZvVXYt9GrJOwgSFjQ&bvm=bv.69620078,d.aWw
But is there evidence of a rebound back to stability?
There is building evidence of a slow temperature decline from the time of the 1257-58 eruption to what is considered to be the coldest periods of the LIA, with a sudden rebound, a span of time that took centuries to slide and then rebound. Caveat: Different models produce different results. One of the major, or THE major, drawback of general circulation models is their failure to reproduce ENSO events and oceanic circulation of ENSO affected upper layer sea surface temperature. In other words, WRT the LIA, they do not simulate the lack of recharge or the subsequent circulation of this now cooler water throughout the globe. Some do a better job of atmospheric circulation but even those do not fully consider oceanic recharge or lack of recharge. Given the abundant volcanic activity throughout this period, Earth would struggle (and apparently fail) to recharge its oceans to the extent that it could recover from such an explosive event quickly. Given the nature of the clouds getting in front of a willing Sun, even under normal circumstances, it is heavy work.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0CDAQFjAD&url=http%3A%2F%2Fclimatechange.rutgers.edu%2Fcomponent%2Fdocman%2Fdoc_download%2F22-mira-berdahl-alan-robock-poster%3FItemid%3D234&ei=PMypU6TNB8mNyATWiIGIDw&usg=AFQjCNG5B6T2UAH2YdFWqeekpm2HZpf-vw
tonyb says:
June 24, 2014 at 12:54 am
Tony, you overestimate your own importance in other peoples minds. I had no clue you were posting as “tonyb”, so to me, you are indeed anonymous. And if I don’t know, there must be many others out there in the same boat.
You have to realize that I read literally hundreds of comments a day. People who use their own names I recognize after a while. And particularly egregious anonymous commenters as well, so I can avoid them.
But most of the time, anonymous commenters are somewhat of a blur, they come and go and use different names, and I’m damned if I’m going to spend the time memorize an alias and associate it with a point of view when you may change your alias tomorrow. In addition, if you post anonymously, I discount anything but scientific claims by about 90%, so I pay much less attention to people using an alias.
Finally, if you polled the folks who read the blog and said “what is the real name of the anonymous poster “tonyb”, my guess is that only one in ten would get the right answer, perhaps one in five … sorry, but it’s not all about you.
Tony, please correct me if I’m wrong, but from my you have used Mann’s work as a part of your extension of the CET backwards in time. However, nowhere that I could find in “The Long Slow Thaw” have you mentioned that because it was built around a bozo math mistake, that the Hockeystick results are meaningless …
In fact, you say the exact opposite, which was
My friend, I fear that if you think the Hockeystick is “essentially confirmed” by the NAS study, you are most definitely way, way out of the loop. You desperately need to spend a week at say Climate Audit doing google searches on these questions. Your opinions are so ungrounded in reality that they are not even wrong.
And how do you combine a claim that you are trying to “to point out the inaccuracies of the Hockey stick” with your claim that the Hockeystick is essentially right? For that matter, where in the Long Slow Thaw do you mention that Mann’s incorrect math mines for hockeysticks? I must have missed that part …
So I fail to see what your point or your purpose was in using the hockeystick.
And me, I agree with the bumper sticker that says “Nice women don’t make history” … go figure.
Is there some part of QUOTE MY WORDS that sounds like a foreign language? You have accused me of “denigrating” you because “our style is different”. How am I supposed to reply to that kind of vague mudslinging, Tony? Obviously you are upset by something I said, but I have no clue what it is, and no way I’m gonna guess. Either tell me EXACTLY what I said that you’re upset about, or go away—I have no use for vague accusations that I’ve hurt your feelings boo hoo, that goes nowhere.
And?
OK, you have “very good knowledge of the last 1000 years of climate”, which you say based on the bogus Hockeystick … is that supposed to be impressive? All that proves is you haven’t done your homework.
And according to you, you’ve actually talked to some climate scientists … is that supposed to convince us that you know your stuff?
Oh, right, I’m the one guy reading this who is ignorant of the true identity of “tonyb” … you vastly overestimate your alias recognition, my friend. It’s funny how aliases have that effect, for some reason they make it hard to know who is using them …
Natural allies? You are promoting the Mann Hockeystick as “essentially confirmed”. I say that it has been demonstrated that it contains an egregious math error which mines for hockeysticks and thus renders the results meaningless. How on earth does that make us natural allies? It certainly doesn’t convince me that your aim is to “use science”, quite the opposite, you’re using Mannian garbage and claiming it is science. And to top it off, you don’t even quote me when you attack me, hardly the action of a natural ally in my book.
Bizarrely, you’ve just done it again, claiming now, in a final bit of throwaway mudslinging, that I “misinterpret” you, one more uncited, unreferenced attack before you go. WHERE did I misinterpret you, Tony, and WHAT did I misinterpret? Without those, it’s just cheap sniping at me on the way out the door, and I don’t do well with that.
Look, Tony, I’m sorry I didn’t snap to attention when I read “tonyb”, but it’s one of the results of your choice to post anonymously. Not my choice. Yours. When you post anonymously, you lose some things, and name recognition is one of them.
And I regret that you are upset, and I’m happy to discuss that. Not only that, but I’m a man who apologizes when I’m wrong, I just had to do it over at Jo Nova’s … but you have to let me know exactly what I said that you disagree with. I’m not going to guess.
Best regards,
w.
Konrad: Thirdly, we know that surface UV variance in the last 3 decades has been two orders of magnitude greater than TSI variance.
Can it be shown that changes in uv irradiance correlate with changes in Earth surface temperature?
The thermal structure and composition of the atmosphere is determined fundamentally by the incoming solar irradiance. Radiation at ultraviolet wavelengths dissociates atmospheric molecules, initiating chains of chemical reactions—specifically those producing stratospheric ozone—and providing the major source of heating for the middle atmosphere, while radiation at visible and near-infrared wavelengths mainly reaches and warms the lower atmosphere and the Earth’s surface1. Thus the spectral composition of solar radiation is crucial in determining atmospheric structure, as well as surface temperature, and it follows that the response of the atmosphere to variations in solar irradiance depends on the spectrum2. Daily measurements of the solar spectrum between 0.2 µm and 2.4 µm, made by the Spectral Irradiance Monitor (SIM) instrument on the Solar Radiation and Climate Experiment (SORCE) satellite3 since April 2004, have revealed4 that over this declining phase of the solar cycle there was a four to six times larger decline in ultraviolet than would have been predicted on the basis of our previous understanding. This reduction was partially compensated in the total solar output by an increase in radiation at visible wavelengths. Here we show that these spectral changes appear to have led to a significant decline from 2004 to 2007 in stratospheric ozone below an altitude of 45 km, with an increase above this altitude. Our results, simulated with a radiative-photochemical model, are consistent with contemporaneous measurements of ozone from the Aura-MLS satellite, although the short time period makes precise attribution to solar effects difficult. We also show, using the SIM data, that solar radiative forcing of surface climate is out of phase with solar activity. Currently there is insufficient observational evidence to validate the spectral variations observed by SIM, or to fully characterize other solar cycles, but our findings raise the possibility that the effects of solar variability on temperature throughout the atmosphere may be contrary to current expectations.
http://www.nature.com/nature/journal/v467/n7316/full/nature09426.html
Greg Goodman says:
June 24, 2014 at 1:15 am
Thanks, Greg, always good to see someone actually crunching the numbers. However …
First, it’s not “my choice of end date”. Those are the standard dates of the Dalton minimum, I didn’t make them up.
Second, what is the actual correlation (adjusted for autocorrelation) between the SSN and the CET? I grow weary of folks claiming correlation, but not calculating correlation. Come back when you’ve done that, and we can discuss it. An overall look at two smoothed datasets is not that useful.
I ask because I calculate the correlation (using detrended annual data 1700-2013) as being 0.3 after after adjustment for autocorrelation, and 0.08 before adjustment, which means that it is not statistically significant no matter how you look at it.
However, since you prefer a different presentation including both datasets (as I often prefer as well), here’s that graph:
As you can see, the oddities are:
1. Other than one cold year, the temperature from about 1785 to 1805 is relatively flat, with little to no cooling.
2. After that, the temperature dropped precipitously until 1813, long after the decrease in the sunspots.
3. The temperature starts rising steadily after that, long before any rise in the sunspots.
Oh, yeah, the correlation over that 71 year period shown in the graphic?
Oh, it’s a whacking great 0.02 … pathetic.
So I’m sorry, but as far as I’m concerned, the claim that the Dalton Minimum caused cooler temperatures is falsified.
w.
Leif,
It would be interesting to get a view from the solar physics community what changes in TSI would be required to produce significant climatic change given
a) TSI variation is stable at +/- 0.1C over many solar cycles.
b) It’s well understood that changes in orbit as per Milanković’s theory can induce climatic change.
It’s the conflation of these two ideas together which is giving some ‘lay’ readers an impression that solar TSI variation alone could be responsible for the mulidecade heating and cooling we’re seeing.
denniswingo says:
June 24, 2014 at 5:31 am
Throw Lamb under the bus? I’ve hardly mentioned Lamb, I’ve used his data, and I’ve said nothing about his point of view regarding solar minima. In fact, I’ve never seen a comment of Lamb’s about either the Maunder or the Dalton.
So … exactly how am I throwing Lamb under the bus?
You see why I asked you to QUOTE MY WORDS, dennis? … and even when I do ask, people like you still think it’s wonderful to toss out bogus claims about what I’ve said.
Quote me or go away. I’m tired of picking spitballs off the wall.
w.
willis Eschenbach: And well-meaning, decent folks like you who for some unknown reason blindly jump in to defend someone else’s uncited fantasy accusation that I’ve made a mistake just make it worse. Didn’t your momma ever tell you to stay out of bar-room fights until you understand the issues?
No, my momma did not tell me anything about barroom fights, and anyway, this is not a barroom and your dispute with tonyb was not a barroom fight. I did not “blindly” jump in, but I do admit to being “decent” and “well-meaning”.
I think you over-reacted to tonyb’s very mild comment.
OTOH, I have read some of the other totally unjustified criticisms of you over the past couple years, and I think I appreciate why “you get your hackles up” (as I wrote once before) so quickly.
But now look at this: Look, Tony, I’m sorry I didn’t snap to attention when I read “tonyb”, but it’s one of the results of your choice to post anonymously.
You didn’t have to “snap to attention”: common courtesy would have been sufficient. I don’t know who tonyb is either, except that he posts at ClimateEtc; you don’t have to know. Your language unnecessarily turned a small problem into a big on, and then a bigger one.
Lastly: Natural allies? You are promoting the Mann Hockeystick as “essentially confirmed”. I say that it has been demonstrated that it contains an egregious math error which mines for hockeysticks and thus renders the results meaningless. How on earth does that make us natural allies? It certainly doesn’t convince me that your aim is to “use science”, quite the opposite, you’re using Mannian garbage and claiming it is science. And to top it off, you don’t even quote me when you attack me, hardly the action of a natural ally in my book.
Bizarrely, you’ve just done it again, claiming now, in a final bit of throwaway mudslinging, that I “misinterpret” you, one more uncited, unreferenced attack before you go. WHERE did I misinterpret you, Tony, and WHAT did I misinterpret? Without those, it’s just cheap sniping at me on the way out the door, and I don’t do well with that.
I can’t find where tonyb promoted the Mann Hockeystick as “essentially confirmed”, but tonyb did write some criticisms of Mann. You assert that tonyb uses “Mannian garbage” without a single supporting instance. I’d suggest that provides 2 of the “misinterpetations” you want cited in the second paragraph. Thee are a number of others, should you care to reread what you wrote about what he wrote.
So you think that Mann is metaphorically a flea infested dog, but tonyb chooses to debate Mann in the published literature. You are natural allies with different strategy choices.
Pamela Gray and I have been pointing to Volcanic Eruptions as known causes of causing global temperatures to drop.
View on iceagenow.info Preview by Yahoo When one thinks about, for instance, what could have possibly caused the extremely rapid drastic global temperature drops during the last glaciation one could conclude that the only explanation is that Sun simply ceased radiating for a number of years. Another related explanation is that the Sun’s radiation ceased reaching Earth for a period of years. One very plausible explanation ties in with known observations of volcanic events whereby ejectae soot blocks Solar radiation affecting Temperature. Piggy-backing that explanation are the known volcanic activities occurring at the time of prior mass extinctions of Life. Yes, the Sun gives Warmth, but what Else could possibly have caused the abrupt rapid Global drop in Temperatures during the series of Glaciations of the prior Ice Ages?
Pamela Gray says:
June 24, 2014 at 7:48 am
As I showed with tephra deposition data, the 1257-58 eruption was not twice the size of Tambora in this standard measure of VEI. What you meant to say was that its sulfate load has been estimated at twice that of Tambora’s. It is not considered the largest explosive volcanic event of the past 7000 years, but one of them, as I pointed out and your own citation says in the first sentence of its abstract:
http://www.pnas.org/content/110/42/16742.full
“Based on ice core archives of sulfate and tephra deposition, one of the largest volcanic eruptions of the historic period and of the past 7,000 y occurred in A.D. 1257.”
What compels you to lie so blatantly, not just once, but twice? It is not I but you who need to get your facts straight.
Furthermore, one of the authors cited in your linked study has this to say about the climatic effect or lack thereof of the 1257-58 eruption:
http://onlinelibrary.wiley.com/doi/10.1029/95JD01751/abstract
Stratospheric loading and optical depth estimates of explosive volcanism over the last 2100 years derived from the Greenland Ice Sheet Project 2 ice core
Gregory A. Zielinski
“The high-resolution and lengthy records of volcanic aerosol deposition in ice cores allow assessment of the atmospheric impact of different styles and magnitudes of past eruptions and the impact of volcanism during periods of varied climatic conditions. The 2100-year long volcanic SO42− time series in the Greenland Ice Sheet Project 2 (GISP2) ice core was used to calculate the mass stratospheric loading (MD) of H2SO4 and resulting optical depth values (τD = MD/1.5 × 1014 g) for individual, and multiple, closely spaced eruptions. Calibration of the calculated optical depth values with other compilations spanning the last 150 years provides a range of values for each eruption or set of eruptions essential to quantifying the climate forcing capabilities of each of these events. Limitations on the use of the results exist because this is only a single ice core, sampling was biannual and transport, and deposition of aerosols is not consistent among individual eruptions. The record of volcanic optical depth estimates is characterized by distinct trends within three consecutive 700-year time periods. The period from 100 B.C. to A.D. 600 is characterized by the fewest eruptions, and optical depth values are lower than those in the rest of the record. The exception is an extremely large signal of 3 years duration that is probably associated with an unknown Icelandic eruption around 53 B.C., with the possible contribution of another high-latitude eruption. The presence of another signal at 43 B.C. suggests that at least two eruptions impacted climate in the middle decade of the 1st century B.C. The period from A.D. 600 to 1300 has intermediate numbers and magnitudes of volcanic events except for the very large 1259 event. Stratospheric loading and optical depths values for the 1259 event are twice that for Tambora (A.D. 1815). The state of the climate system in the middle of the thirteenth century A.D. may not have been sensitive enough to the atmospheric perturbation of the 1259 eruption, thus the apparent lack of abundant proxy evidence of climatic cooling around A.D. 1260. The most recent 700 years (A.D. 1400–1985) are characterized by the greatest number of eruptions (half of those recorded over the 2100 years of record) and, in general, the highest stratospheric loading and optical depth values for individual and the combined effects of multiple eruptions. The large Kuwae eruption (A.D. 1450s) may have perturbed the atmosphere at least as much as Krakatau and possibly of a magnitude similar to Tambora. Multiple eruptions in the 50-to 60-year periods from A.D. 1580s–1640s and A.D. 1780s–1830s may have had a significant impact on enhancing the already cool climatic conditions in those time periods, particularly around A.D. 1601 and 1641. These findings imply that multiple eruptions closely spaced in time are more likely to have a major impact on a decadal time scale when existing climatic conditions are in a more sensitive or transitional state. The GISP2 ice core record also indicates that several relatively unknown eruptions may have been large sulfur producers during the 17th and 19th centuries A.D., thereby warranting further studies of those particular events.”
Had you read further into the study you linked, you’d have seen that it too discusses the fact that adding more sulfate doesn’t cause a linear increase in climatic effect.
As for the main point, ie the cause of the LIA, it was not the 1257-8 eruption. There is, as noted above, no evidence to support a climatic effect, let alone lasting, from this event, nor any other single eruption or multiple eruptions, much as Warmunistas try to make believe that’s so. You claim without support that evidence is accumulating for an earlier onset of the LIA. Besides your mention in passing of burials, please present this accumulation. Thanks.
Climate did start to decline in downs and ups after the height of the Medieval Warm Period, but didn’t cross over into colder than post-Optimum normal until the latter 14th century at the earliest, as shown in the first IPCC’s graph, later expurgated. For example, the Greenland Norse survived into the 15th century. On 14 September 1408, Icelander Thorstein Olafsson and local girl Sigrid Björnsdottir were married in the church on Hvalsey Fjord.
In much of the world, the LIA didn’t register until about 1500. For example, eastern China:
http://adsabs.harvard.edu/abs/2002AGUFMPP71C..09L
“Abstract
The long-term climatic pace has often been interrupted by short-term abrupt changes. The Little Ice Age and Medieval Warm Period represent the two most important such changes over the last two millennia. Largely due to a dearth of high-resolution climatic records, our knowledge on the spatial extent, duration, and moisture characteristics of these two events is incomplete, and this has hampered our understanding of the driving force causing them as well as the recent global warming trend. Here we present high-resolution climatic records reflected by the delta 18O and delta 13C in three stalagmites from limestone caves in China…Although the three caves are more than 1000 km apart, their long-term delta 18O records show patterns that are remarkably similar. The records show that in eastern China, the Medieval Warm Period started around 1000 AD and lasted until 1500 AD. A brief cooling during this warm interval occurred around 1150 AD. The Little Ice Age in China started at around 1500 AD and ended in the mid-1800s. Since then, all three locations show a warming trend that has been observed elsewhere in the world. The records of S312 and SF show that for the past 4,000 years, the two locations has had similar temperature variations with five distinct warming trends, but a different moisture variability which is probably more sensitive to local atmospheric circulation changes than temperature. In general, it was relatively dry during the Medieval Warm Period and wet during the Little Ice Age in eastern China. Of the five warming trends, the most recent one is the strongest.”
Moreover, volcanoes can’t explain the previous warm and cold periods of the Holocene or any prior interglacial, although it’s possible that volcanism increases after glacial phase ice sheets start to melt during the initial warming leading to interglacials.
A C Osborn says:
June 24, 2014 at 5:56 am
Typical of you to talk emissivity when Konrad talks Absorption, can’t you even read what he has said?
Ummm … before climbing on your high horse you might google Kirchhoff’s law, AC. It states that absorptivity is equal to emissivity … so your claim is wrong, and your gratuitous insult just makes you look vindictive.
w.
Tom O says:
June 24, 2014 at 6:06 am
I don’t know who you think made the claim that “the Sun doesn’t rule the heating”, but it certainly wasn’t me. Is there something wrong with your ability to read the following from the head post?
But nooo, a polite request means nothing to Tom O, requests are for the common people, not for Tom, so you just grab your nearest fantasy of what I said and you run with it …
Seriously, folks. You look like jerks when you do this. I will continue to point and laugh. Quote what you disagree with, or go away, I’m not interested.
w.
PS—Tom, what I actually said was totally different from your claim. I put it in the first sentence, so fools like you might actually notice it. I said:
And I went on to explain that the “slow changes” meant the Maunder, Dalton, and other minima.
Learn to read.
After I objected to Ulric calling sunspot cycles 12-14 a “solar minimum”, I asked:
Ulric Lyons says:
June 24, 2014 at 6:35 am
Since I’ve never heard of that I googled it, and I got this, emphasis mine:
I also don’t find it in any list of solar minima …
w.
sturgishooper says: June 23, 2014 at 10:55 pm
“It still pales against Tambora.”
I have shown you several lines of evidence that the 1257-58 eruption was a greater event than that of Tambora. You say otherwise. Where is your evidence? I have not once come across a line of research that says Tambora was greater or even equal to the earlier event. So please, fill me in. I want links.
Matthew R Marler says:
June 24, 2014 at 1:13 pm
I don’t know why Willis or anyone else would imagine that Tony Brown’s work supports Mann. Willis must have missed this WUWT post from less than a year ago, for instance:
http://wattsupwiththat.com/2013/08/16/historic-variations-in-temperature-number-four-the-hockey-stick/
Let alone consider Tony Brown “anonymous”.