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
lsvalgaard says:
June 24, 2014 at 3:27 pm
IMO I did answer the question, and it’s that, yes, of course you should convert C to F or vice versa.
Apparently you’ve now agreed that there is evidence for a solar influence in Holocene fluctuations, for which recognition I’m glad. But there is also evidence from prior interglacials, so I’m not overstating anything:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDAQFjAB&url=http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F249521092_Cyclic_climate_fluctuations_during_the_last_interglacial_in_central_Europe%2Ffile%2F60b7d52271d554955b.pdf&ei=4wOqU6jZLJXtoASk6oJQ&usg=AFQjCNHrImtooQSqwRkblar8YRRpdY_aSw&sig2=qc0-V6XlDkv4Lk2uUaVIpA&bvm=bv.69620078,d.cGU
Willis Eschenbach says:
June 24, 2014 at 4:09 pm
Did you actually read any of Tonyb’s WUWT posts mentioned by him and others in these comments, to see if in fact, as you imagine, he supports Mann’s HS?
Sturgis: FYI regarding volcanic flux as a metric of explosive power.
“A number of recent studies have used volcanic flux [Zielinski,1 995; Zielinski et al., 1997] and volcanic acid/sulfate concentrations [Robock and Free, 1995] to estimate mass aerosol loadings and to infer the climatic forcing of volcanic eruptions, although caution is essential when such extrapolations and inferences are made from ice core data. Cole-Dai et al. [1997] used a relative scale (volcanic flux normalized against the 1815 Tambora eruption) to compare the magnitude of volcanic events found in different ice cores. An eruption is considered large if its volcanic flux is comparable to or exceeds that of Tambora.”
By this measure, a preponderance of ice cores at both poles places Samalas quite a bit ahead of Tambora. Yes there are volcanos that have spewed larger amounts of tephra, but what does that tell us about the explosiveness of that volcano? Not as much as what gets into the stratosphere measured by fall out at the poles. Clearly you can understand the physics related to shooting something straight up that high. And surely you understand that volcanic flux as an extremely important factor in climate discussions.
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%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2000JD900254%2Fpdf&ei=gQKqU8PfBOmb8AGPsoHIBQ&usg=AFQjCNEtDHWJGVIl_z9X5LvYOjFlxYktqw&sig2=d92c3QcIjkEU8XYOB0xxkw&bvm=bv.69620078,d.b2U
sturgishooper says:
June 24, 2014 at 4:11 pm
IMO I did answer the question, and it’s that, yes, of course you should convert C to F or vice versa.
So one should also convert the overcounted spots to unweighted spots or vice versa. right? In both cases it is just a question about a scale factor, right?
Apparently you’ve now agreed that there is evidence for a solar influence in Holocene fluctuations, for which recognition I’m glad.
This is a standard cheap trick. If you want to pull that one quote my exact words for that.
But there is also evidence from prior interglacials, so I’m not overstating anything
There are no evidence that the changes are related to solar activity, so you are overstating a lot.
Thanks to thingadonta for linking my articles on the timing implications of ocean equilibration. I just want to clarify the sense in which the timing issue can and cannot be properly described as a “lag.”
What Usoskin, Solanki and a host of others keep claiming is that the 20th century’s high level of solar activity cannot be responsible for late 20th century warming because solar activity was not rising at this time. When I press them on whether they are actually claiming that it is the TREND in solar activity rather than the LEVEL that would drive warming they admit that they are assuming very rapid ocean equilibration (so that solar activity would indeed have to keep going up to cause continued warming. But this assumption does not stand up to the least bit of scrutiny, and without it, temperatures will not stop rising when the forcing stops rising, but will only stop when the system equilibrates to the new higher LEVEL.
Notice that there is no lag in the warming effect of an increased forcing. (There could be some lag in the time it takes feedbacks to work through, but that doesn’t alter the fact that forcing effects are immediate. I would also expect feedbacks to be close to zero, or negative, if Willis’ excellent Thermostat Hypothesis is correct.) The timing of the appearance of this warming in the surface temperature record can be obscured by ocean oscillations but if we had good heat content data, we would see the warming immediately.
Where there IS a lag is in the inflections points. When solar activity hits its peak and turns back down the forcing effect does not turn immediately from warming to cooling. Just as the day continues to warm well past noon, so too will warming continue until the forcing effect from the level of solar activity falls below the level needed to maintain the temperature of the system. After 3 PM the level of diurnal insolation has fallen below the level needed to maintain the achieved daytime temperature and the day starts to cool. Diurnal insolation drops at noon, then after three more hours of warming the temperature levels off and start to drop.
In sum, changes in the LEVEL of forcing immediately affect the heat content of the system. Changes in the trend affect the trend in temperature with a lag. Maintaining precision in the use of these terms helps to avoid confusion. Just saying that there is a lag in which solar effects show up prompts the question of why. Why wouldn’t warming be immediate? Yes it would be (except as obscured by the random, not lagged, effects of ocean oscillations). It is only inflections that show a lag.
george e. smith says:
June 24, 2014 at 2:17 pm
Obviously, YOU didn’t “read the post at the head of these comments “. Not only that, but you’re the latest in a line of charming fellows who try to impute a point of view to me without a quotation. All that does is get your face slapped, and deservedly so.
What I actually said was:
Since Eddy could only come up with a couple of references in obscure journals as prior art, I stand by that characterization.
However, I NEVER said that the recognition of the Maunder occurred in 1976, nor did I say anything like that. I said nothing about the “onset of recognition”, that’s all you.
In fact, the Eddy paper I cited gave a complete history of the recognition and naming of the Maunder minimum, so I figured nobody would be dumb enough to think I claimed recognition of the Maunder started in 1976 … foolish me.
Not only that, but I already explained this upstream when some other jerk made the exact same accusation. And I thought that might put the question to bed … foolish me.
In any case, are you really too distracted to notice when I say QUOTE MY WORDS, or are you just ignoring what I said, or do you have Oldztimers Disease where you forget what you just read?
It gets old, george, and every time you try this your reputation slips a bit. I’d give it up before it slides down to your knees …
w.
Alec Rawls says:
June 24, 2014 at 4:25 pm
What Usoskin, Solanki and a host of others keep claiming is that the 20th century’s high level of solar activity cannot be responsible for late 20th century warming
The problem here is that the 20th century solar activity was not particularly high compared to the previous two centuries, regardless of how many repeat the myth that it was.
Pamela Gray says:
June 24, 2014 at 3:41 pm
You are standing by your lie that it was the biggest eruption of the last 7000 years, when your own source claimed only “one of the biggest”? Interesting. Even Santorini was smaller than Tambora.
Your own source and those I linked or quoted plainly state that doubling sulfate load doesn’t double its climatic effects. Now here you come, quoting the less recent Oppenheimer (2003) to the same effect, again destroying your own case with a quotation you provided! What part of “non-linear” do you not understand?
When I say stop digging, I really mean it.
I’m supposed to buy your conclusion based upon your “literature review”, when your own sources and the AGU’s VEI disgree with you? Sorry. No sale.
Please show how in your imagination Samalas caused the Little Ice Age. Oppenheimer says nothing about ENSO. He does state that the sulfate spike should have produced “a stronger climate forcing than hitherto recognized”, because “the comparably sized Kuwae eruption has been associated with a cool NH summer in AD 1453 (Briffa et al., 1998) and a sulphate anomaly in the GISP2 core at AD 1460”.
But the more recent studies I cited found no evidence of climatic effect. However, more importantly, neither they nor Oppenheimer argue that Samalas caused the Little Ice Age. So first, please show a long-lasting climatic effect in physical or historical records resulting from this eruption, then how these assumed effects led to the centuries long LIA, while also explaining the warmer decades between c. 1260 and 1350, 1400 or 1500, when the LIA is variously argued to have begun.
Thanks.
Willis Eschenbach says:
June 24, 2014 at 4:27 pm
What you said was, “Modern interest in the Maunder sunspot minimum was sparked by John Eddy’s 1976 publication of a paper in Science entitled “The Maunder Minimum”.” This is blatantly false on its face, as I and others noted.
You yourself reference Lamb’s 1965 paper! Talk about Oldtimers’ Disease! You couldn’t recall what you had written in a previous paragraph. Or to you is 1965 not “modern” but 1976 is?
Seriously, are you OK?
Tonyb says:
June 24, 2014 at 2:22 pm
I said specifically and more than once that you supported Mann by claiming that the hockeysticks had been “essentially confirmed”, viz:
Sorry, but that’s just not true. The Hockeystick has never been “essentially confirmed”. How could it be, it’s the result of a newbie mathematical mistake … a fact which you never mentioned, despite it being central to the question. So yes, you are supporting Mann with those kind of claims, and yes, I told you this before so your current mystery about why I said it is … well … curious.
Really? You want to go there? Well, OK … Janice tried to use the time of my grief at the death of my father-in-law to sell me Jesus. I got upset, but I apologized. However, most everyone (apparently including you) seemed to think Janice’s actions were perfectly fine and acceptable.
So I asked everyone at the time if doing that at a Christian eulogy would be appropriate … I mean, if a Moslem tried to use a Christian’s time of grief to tell him that Jesus is a liar who can never bring him lasting peace, and try to convert him to Islam, would that be an acceptable and moral and right thing to do? Simple question. I just took exactly what Janice had said to me and substituted religions.
No one, including yourself from your account, had the stones to even try to answer the question. Not one person.
I fear that everyone refusing to answer that simple question is the shameful part of the episode. I stand by what I said and did. Yes, I initially responded out of my grief, and as a result my first response was over the top, and I apologized for that. Four times, in fact, because people weren’t satisfied. And after that they wanted another apology, but I figured four was good enough.
However, I didn’t apologize for calling Janice out on her attempt to use the time of my grief to sell me Jesus, nor will I … and that seems to have driven some people round the twist.
You, on the other hand, chickened out and refused to even take a stand … so you’ll forgive me for ignoring your attempt to teach me morals. You forfeited that right when you wouldn’t answer a simple question about the morality of Janice’s actions.
Tony, I didn’t mind your “extremely mild comments”. I objected to the fact that you had accused me without quoting what I said. It had nothing to do with relative mildness, it had to do with a simple fact. I can defend what I’ve said. But I can’t defend myself against your fantasies of what I said. You accused me, for example, of “misunderstanding” what you said.
But without a quote to show what I misunderstood, that’s just underhanded mudslinging, regardless of whether it is mild or not. I won’t put up with that kind of scurvy attack, because there’s no way on earth to defend myself against it.
So … I asked you what you meant.
However, as with my question about Janice, you haven’t answered … your choice, but don’t pretend that the ball’s in my court when it’s you that isn’t answering the questions …
w.
Tonyb says:
June 24, 2014 at 2:26 pm
Tony, I’ve explained my reasons in great detail, in no less than 12 comments, both to you and to others. If you still have questions, fine, perhaps you should ask them. But you absolutely cannot claim that I have stinted in my efforts to explain my position to you, I’ve done little but that in regards to you.
However, if you want to hop on your horse and ride away from answering my questions and continuing the discussion, that’s your option.
It’s also your choice, not mine. I’m still up for further clarification. For example, you could start by showing where in your “Long Slow Thaw” you point out that Mann’s Hockeystick paper was based on the newbie mathematical mistake of using an un-centered principal components analysis, and as a result it was meaningless … I missed that part.
Or not, you can keep riding.
w.
AW I think youre allowing a warmist troll to wreck your site chao
sturgishooper says:
June 24, 2014 at 4:41 pm (Edit)
While you and others CLAIM that it is false, to DEMONSTRATE that it is false you’d have to show significant interest prior to 1976 in the subject of temperatures during the Maunder. Eddy could only find a few papers that discussed temperatures during the Maunder prior to his study. Not only that, but the earliest reference which Eddy found was dated 1961 …
Which means to me that there was little interest pre-1976. As just one example, Lamb wrote the entire paper that I cited and never mentioned either the Maunder or solar variations even once … so it couldn’t have been a big feature in the climate landscape in 1965.
Nor is this surprising, as until the 1970s climate wasn’t really that much on the radar, so there was little interest in temperatures and the sun.
However, subsequent to Eddy’s study, interest went way up, with many, many papers referencing Eddy’s work in their investigations. There have been 1700 papers citing Eddy’s work since 1976, and I know of only about a half dozen papers at the most prior to that, with most of them in the previous decade. … that’s called “sparking the modern interest”, sturgis. It doesn’t mean there was no interest prior to that, which is why I called it “modern interest”. It means that it brought the Maunder to the forefront.
So I fear that you haven’t even begun to substantiate your claim of substantial interest in the subject prior to 1976.
w.
Leif writes:
Muscheler 2007:
Whether solar activity in the second half of the 20th century was “exceptionally high” or merely “high” makes no difference for the question of whether it could explain late 20th century warming. So long as the climate system has not yet equilibrated to a higher level of forcing (by whatever mechanism that forcing is transmitted) then warming will continue until equilibration is reached, and there is no reason to think that equilibration does not take many decades. Indeed, this is what the IPCC assumes in its models when it conducts its “commitment studies.” As I previously quoted from the draft AR5:
Up to 2.5C of continued warming over the next 100 years from the current level of forcing… This is radically inconsistent with the claim that ocean equilibration is close to instantaneous, as these same scientists assert as their grounds for dismissing solar activity as a possible explanation for late 20th century warming.
Dr Norman Page says:
June 24, 2014 at 3:24 pm
Thanks for that, Dr. Page, and I’d be happy to look at it … but where is it? A link, my kingdom for a link …
w.
sturgishooper says:
June 24, 2014 at 1:14 pm
I hope the young Norse couple wed in 1408 sailed or rowed away to Iceland, where the LIA, while terrible, at least didn’t wipe out everyone (there being no Inuit to survive or thrive). Iceland has such good records, it might be possible to find out their fate, if they went to live with his family rather than stayed with hers, to perish or be absorbed by the Inuit (the Eskimos of Greenland & eastern Canada).
IMO one reason why the Kuwae (c. 1453) & Tambora (1815) eruptions left a climatic signature, while Samalas (c. 1257) not so much, is because they occurred during the already tough LIA. Tambora of course was also during the coldest interval of the Dalton Minimum.
There were what would now be called extreme weather events in Europe in the late 13th century, & the Great Famine of 1315-17, followed by the Black Death from 1346, plus nearly constant warfare, but intervening decades remained warmer & more equable than usual for the past 3000 years or so. In fact the bounty of the Medieval Warm Period made it possible to breed & raise big war horses capable of carrying knights in full plate armor, which evolved during the 14th century, plus sometimes their own armor.
Matthew R Marler says:
June 24, 2014 at 3:42 pm
Seconded, and also for your calm demeanor. I envy your patience.
w.
1. Sulfur injection into the stratosphere, as measured by ice core records indicate that Samalas was likely the cause of the well-recorded cold and cold-related events around the globe.
2. Volcanic sources of atmospheric sulfur appeared to be ubiquitous during the span of time encompassing the LIA, thus continuing to affect climate. The ice cores record only extremely explosive volcanic events thus sulfur in the ice cores at both poles would indicate stratospheric sulfur sufficient to reduce solar insolation at the surface.
link: http://climate.envsci.rutgers.edu/IVI2/
3. Models support the hypothesis and observational record that large equatorial injections of sulfur into the stratosphere can disrupt oceanic and atmospheric patterns and teleconnections at least on a hemispheric basis, in particular the processes involved in ENSO.
“Impact of Strong Tropical Volcanic Eruptions on ENSO Simulated in a Coupled GCM” Masamichi Ohba et al (paywalled)
4. My speculation is based on my literature review and Bob Tisdale’s work on the recharge/discharge process of ocean heat. It is shown in the literature that these eruptions slow the Walker circulation, trigger and enhance El Nino-like equatorial conditions, and would thus lead to oceanic heat loss, cloudiness, and direct atmospheric cooling. This veiling and subsequent cloudiness on a global scale further decreases any solar ability to recharge an ocean that is losing heat. Inbetween sulfur veil clearing the system takes haulting steps to regain sufficient solar insolation to recharge depleted ocean heat stores. However, the now circulating colder water now brings cold temperatures to land, especially during re-injections into the stratosphere, as was the case during the LIA. As long as these injections were happening equatorially, El Nino like events and slowed Walker Circulation would encourage heat discharge, not recharge. Eventually the supply of ocean heat becomes seriously low leading to extreme cold on a global basis. It may take centuries for sufficient recharge to reach an unequal seasaw ocean heat balance returning climate to a more normal pattern.
5. Temperature proxy records show that there was a slow step-fashion decrease in global temperature from a warm period. I speculate for that to happen the oceans are losing heat, not gaining heat. Volcanism, especially of the kind that occurred during the LIA is a candidate for that long up and down slide to the depths of the LIA.
6. My next search will be related to how did we get out of it. Once the force is removed that has been preventing sufficient oceanic recharge, the oceans should be able to crawl back to a previous level of oceanic recharge/discharge that keeps us fairly comfortable between cold and warm normal weather pattern variations.
Willis Eschenbach says:
June 24, 2014 at 5:36 pm
It’s easy to find material on the Maunder from the ’60s & first half of the ’70s. You have but to look:
http://www.eh-resources.org/timeline/timeline_lia.html#lamb
See the graph at the top of this article, taken from H.H. Lamb, “Climatic Fluctuations”, in H. Flohn (ed), World Survey of Climatology. Vol.2. General Climatology (New York: Elsevier, 1969), p. 236; & Schneider, S. H., and C. Mass, “Volcanic dust, sunspots, and temperature trends”, Science, 190 (1975) 741-746.
Note reference to sunspots from Ellsworth Huntington’s “Civilization and Climate”, Yale, 1922.
http://books.google.com/books?id=-qooAAAAYAAJ&pg=PA91&lpg=PA91&dq=sunspots+climate+1930&source=bl&ots=tZPEq1Q3yn&sig=X6TwtW2A_GD4sRJgqQAsZnRPQOU&hl=en&sa=X&ei=hhyqU6aPGYX-oQTr8YCoBA&ved=0CE0Q6AEwCA#v=onepage&q=sunspots%20climate%201930&f=false
http://en.wikipedia.org/wiki/Ellsworth_Huntington
I know that anecdotes are verboten, but I studied sunspots & climate as an undergrad at Stanford, 1969-73.
Leif
Berggren does say
“We observe that although recent 10Be flux in NGRIP is low, there is no indication of unusually high recent solar acitvity in relation to other parts of the investigated period [the last 600 years].”
He also says
“occasional short term differences between the two sites indicate that at least two
high resolution 10Be records are needed to assess local variations and to confidently reconstruct past solar activity”
Look at his Fig1 in the link you gave. The DY3 data is a beautiful; example of how the 20th century
solar activity climbs ( falling Be Flux) to levels not seen in the previous 600 years.
All interpretations of data are cherry picked one way or another. Scientific insight is the ability
to know which cherries to pick.
http://onlinelibrary.wiley.com/doi/10.1029/2011GL050168/abstract
Link regarding the proposed volcanic LIA trigger.
Pamela Gray says:
June 24, 2014 at 5:50 pm
1. Sulfur injection into the stratosphere, as measured by ice core records indicate that Samalas was likely the cause of the well-recorded cold and cold-related events around the globe.
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Please provide the records which support this assertion, contrary to the recent studies linked & quoted here above which could find none. As noted above, your own link found no summer effect comparable to Kuwae, but just assumed it must have happened, despite lack of support. Thanks.
Then please explain how the many long warm intervals between c. AD 1260 & 1500 happened. If they coincide with periods of low volcanic activity, please make that connection, too. Thanks again.
Then please provide evidence for volcanoes causing the other cold periods in Holocene climate history comparable to the LIA, & explain why the planet has been in a long term cooling trend for over 3000 years, broken at fairly regular intervals by warm spells, the peaks of which are also declining. Volcanoes have a lot for which to answer. Thanks yet again.
Not to disrespect your work or all the countless hours of dedicated research… but why?
Why must there be some Holy Grail, magic formula, simplistic answer to everything?
Why can’t it be a more complex combination of contributing factors that influence our climate?
Sorry to be such a dolt but seriously… the mindset of A, B, C multiple choice? Have your ever considered “all of that above”?
Here is where I think possible further research is needed in the trigger and continued step-fashion slide into the LIA. They need to find a way to model the recharge/discharge function of ENSO processes under conditions of low solar insolation due to the sulfur veil, cloudiness, and decreased Walker Cell circulation. Then send those un-recharged cooler waters around the globe. Continue to hamper the recharge phase and force the equatorial region into sustained heat losing El Nino’s till sulfur injections reduce to background noise.
Milo, all of the links I have included note cold and cold-related events around the timing of Samalas. Do you need more?