Maunder and Dalton Sunspot Minima

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? wiki 400 years of sunspot observationsI 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? …

lamb england winter index wo datesFigure 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:

lamb england winter index wrong datesFigure 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.

lamb england winter index w datesFigure 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:

berkeley earth land temperature plus daltonFigure 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,


[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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Matthew R Marler

As usual, I am grateful for your work: thank you.

rod leman

Well, I would say that it is an incorrect analysis to compare temp with any single forcing. There are multiple forcings for Average Global Temp and to make a logical comparison of Temp vs the Solar Intensity you have to adjust the temp graph to EXclude other temp forcings like atypical volcanic activity, El Nino/La Nina, etc.

Warren Bonesteel

Mass index?: Earth, rock, seas/lakes? Once the earth starts to warm up after a solar minimum, how long does it take to affect the system? Same-same wrt warming. Is there a ‘lag’ in the system?

Willis, thank you. To be fair you should reference Jo Nova’s blog post and the notch filter idea with a link or two.
[As soon as I left for town I realized I’d forgotten to link to Jo’s blog, thanks for the reminder. Back now, it’s done. -w]

It is often forgotten that the descent into the LIA began around 1200 AD. The first regions to be affected were in the Arctic, e.g. Greenland.
By the 14thC, Europe too was feeling the effects of a colder, wetter climate.
Dalton and Maunder may have marked the coldest dips, but the explanation behind the LIA as a whole is far more complex, and very little understood.


“Once again, the data absolutely doesn’t support the idea of the sun ruling the temperature. ” Actually this only speaks of sunspots.


May I ask whether or not you checked the UV emissions during sunspot cycles and the lack thereof during the Maunder Minimum? I though, and I may well be wrong here, but UV output has effect on winter weather and by extension the lack of UV activity during the Maunder Minimum may well have some effect during this particular downturn during that period.

NZ Willy

You’re confusing cause and effect. The solar sunspot cycles are an effect from a deeper Solar condition — the issue isn’t insolation (or lack of) from sunspots, but from the whole solar activity. The AP magnetic index is an example — a change in the big picture, and the sunspots are just a symptom.


The cycle ends, the activity decreases. Solar magnetic field is weakening. The Earth’s magnetic field is weakening. We’ll see what happens.


This analysis is pretty much meaningless relying as it does on one set of data about one location. To quote from an article by Burnel ( , “What Lamb’s winter severity map makes most evident is that even across a short arc of the globe, while there is evident a generalized pattern of change through time, this pattern can be experienced quite differently at different points along the arc. Some places experience the change more sharply than others. Sometimes the change is so much out of phase that the trend at the same time in different places is reversed.” For an analysis of the impact of solar variation on climate change on a global scale is needed.

The CET supports the Maunder Minimum at statistical significance, the Dalton less so.
For instance, here are some seasonal and monthly cold records in the CET:
Autumn: 1676
Winter: 1683/84
March: 1674
May 1698
June 1675
July 1816
September 1674 and 1807 (tie)
Other records are close to the usually quoted end dates for the MM (1645-1715) & DM (1790-1830).


Six chronologies based on the growth of Scots pine from the inland of northern Fennoscandia were built to separately enhance low, medium, and higher frequencies in growth variability in 1000–2002. Several periodicities of growth were found in common in these data. Five of the low-frequency series have a significant oscillatory mode at 200–250 years of cycle length. Most series also have strong multidecadal scale variability and significant peaks at 33, 67, or 83–125 years. Reconstruction models for mean July and June–August as well as three longer period temperatures were built and compared using stringent verification statistics. We describe main differences in model performance (R^2 = 0.53–0.62) between individual proxies as well as their various averages depending on provenance and proxy type, length of target period, and frequency range. A separate medium-frequency chronology (a proxy for June–August temperatures) is presented, which is closely similar in amplitude and duration to the last two cycles of the Atlantic multidecadal oscillation (AMO). The good synchrony between these two series is only hampered by a 10-year difference in timing. Recognizing a strong medium-frequency component in Fennoscandian climate proxies helps to explain part of the uncertainties in their 20th century trends.

I should perhaps have added that the CET starts in 1659, so misses the first 14 years of the MM.


The 2009-2010 period was the quietest solar period of our lifetimes and it coincided with record high latitude blocking patterns (cold air distribution) in both hemispheres. What fascinated me was the very active series of stratospheric warmings that occurred during this solar minimum. These are things we couldn’t really measure during the prior minima, so I suspect we’ll learn a whole lot in the years ahead!


Divide by the square root of -1? LOL!
Educational and entertaining. Thanks

Check Figs 8 and 9 at
Here are some quotes.
“Furthermore Fig 8 shows that the cosmic ray intensity time series derived from the 10Be data is the most useful proxy relating solar activity to temperature and climate. – see Fig 3 CD from Steinhilber
NOTE !! the connection between solar “activity” and climate is poorly understood and highly controversial. Solar ” activity” encompasses changes in solar magnetic field strength, IMF, CRF, TSI ,EUV,solar wind density and velocity, CMEs, proton events etc. The idea of using the neutron count as a useful proxy for changing solar activity and temperature forecasting is agnostic as to the physical mechanisms involved……..
The trends in the neutron count over the last few solar cycles strengthens the forecast of coming cooling made from projecting the PDO and Millennial cycle temperature trends The decline in solar activity from 1990 (Cycle 22) to the present (Cycle 24) is obvious……..
It has been estimated that there is about a 12 year lag between the cosmic ray flux and the temperature data. see Fig3 in Usoskin et al…19U.
With that in mind it is reasonable to correlate the cycle 22 low in the neutron count (high solar activity and SSN) with the peak in the SST trend in about 2003 and project forward the possible general temperature decline in the coming decades in step with the decline in solar activity in cycles 23 and 24.
In earlier posts on this site at 4/02/13 and 1/22/13
I have combined the PDO, ,Millennial cycle and neutron trends to estimate the timing and extent of the coming cooling in both the Northern Hemisphere and Globally.”

Chris Schoneveld

In a Maunder minimum shouldn’t we also expect the summers to be colder? Why only focus on the winter severity index?


It’s whatever Leif says it is. If Leif says minima dont cause cold spells then discussion over.

Jeff L

Interesting work , Willis – thanks for compiling that , as well as the other recent solar correlation posts.
There is an obvious next question this brings to my mind: What exactly has driven these shorter period changes in climate (by shorter, I mean sub-Milankovich scale cycles) ? It certainly wasn’t coal fired power plants and SUVs. It is the most fundamental question and one the CAGWers have no answer for.
I will say that if the skeptic crowd could develop a compelling theory / model of these past changes, it could potentially be possible to unravel the model temperature signal in terms of an natural signal & anthropogenic signal (if any).
If done with proper scientific rigor, it could be the final nail in the CAGW coffin.

Why are you guys obsessed about 11 year cycles….it’s 22 year cycles stupid! The temperatures changes are accociated to geomagnetic not solar….please redraft


Would like to see a graph with ACTUAL TEMPERATURE rather than some sort of non-defined “Severity index”.

Jeff L

WxMatt says:
June 23, 2014 at 12:39 pm
“The 2009-2010 period was the quietest solar period of our lifetimes and it coincided with record high latitude blocking patterns (cold air distribution) in both hemispheres. What fascinated me was the very active series of stratospheric warmings that occurred during this solar minimum.”
And of course the blocking can lead to extreme cold over Europe & eastern NA.
From the Eddy paper:
“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). ”
Drought in the SW is also consistent with persistent blocking – just like we saw this winter.
But is there any correlation between this high latitude blocking & solar activity? We know there is a correlation / causation from polar stratospheric warming events but do those have any relationship to solar activity? Hard to say from the data presented here – temp records would all depend on where blocking sets up (and if the data are from the cold side or warm side of the block).


I can’t say that I’d “stand behind and defend” this evidence as I haven’t looked into it much myself, but I would be interested in seeing your analysis on this:
Yes, I realize the paper’s authors argue for a regional, rather than global, effect of solar activity. But perhaps regional effects during the very complicated little ice age altered people’s perceptions of it?

MattN says:
June 23, 2014 at 1:02 pm
CET temperature data clearly show the 1659 to 1715 partial Maunder Minimum period statistically significantly colder than the following interval 1716 to 1789, with the shorter Dalton Minimum, 1790 to 1830, less so, but still cooler. It all being the LIA, there are some unusually cold years in the warmer mid-18th century period as well.

Temperature declines clearly seen in the HadCET time series:

kadaka (KD Knoebel)

Having fun with graphs:
It is easily shown the AMO precedes the SSN when the planet is warming, thus AMO could predict SSN thus solar activity. It is when the planet is cooling that SSN leads AMO.
The PDO is more complex, but since the most recent warming phase starting 1979 which I think Tisdale called The Great Pacific Climate Shift (something like that), SSN clearly leads PDO:
Since it is clearly seen the sunspot cycle can lead PDO and AMO, and they go on to influence global temperatures, it is obvious the sunspot cycle influences global temperatures. There are the graphs, it must be true.

Of course, as I said, that’s just having fun with graphs. Although I would like to know the real reasons the graphs can line up so much, mainly as to why PDO and AMO “beats” line up as they do with the sunspot cycles, switching who’s first between cooling and warming phases.

MattN says:
Would like to see a graph with ACTUAL TEMPERATURE


Underlying this work is the unstated presumption that sunspots are correlated with solar output. Is that true? How could we know?

Alan Poirier says:
June 23, 2014 at 1:10 pm
Starting in 1659 rather than 1772, to capture the Maunder as well as the Dalton Minimum:

the decline of the total solar irradiance ( a product of the two century bi-cenntenial solar component) gives indisputable evidence that the earth is heading for a new little ice age.(see Abdussamatov and Piers Corbyn)

JJM Gommers

A plausible mechanism might be a slightly lower irradiation, including lower UV, effects directly the amount of H2O in the atmosphere in the tropics. I assume H2O is a greenhouse gas although it,s not mentioned in the consensus literature. The result is a decline in temperature very small but in enthalpy more pronounced due to the latent heat of the water vapour. This cascades in the higher latitudes and subsequently lower temperatures. As soon as this process progresses the temperature especially at the higher latitudes accelerates to drop further. Maybe changes in weatherpattern during this process
might have influence as well.


Willis – turn off the Sun and then check the temperature. Anyone who assumes the Sun is not the main driver is “over-analysing” the simple reality that without the Sun we might as well be Neptune.


Several years ago I looked at volcanic indices and there were strange changes in the classes/frequencies of volcanic activity during the maunder (iirc) minimum. There are many potential directionality/cause/effect possibilities (did the effects of volcanic activity change the visibility of sunspots?). I don’t remember what I did and the hard-drive I did it on was fried.

Rud Istvan

There are at least 3 climate drivers: sun, natural variation beyond solar (e.g the apparent multidecadal Arctic ice cycles probably driven by ocean circulation and which affects albedo and thermohaline circulation), GHG. Untangling the mix is important, as these may operate on different time scales with different leverage, and with varying rates of feedbacks both positive and negative as they interact. After all, something was forcing change before CO2, and it probably hasn’t gone away.
As for the sun as one of the things in the mix, read Hoyt and Schatten, The role of the sun in climate change, Oxford University Press, 1997 (279 pp.) See also Hoyt, variation in sunspot structure and climate, Climate Change 2: 79-92 (1979). As for possible coupling mechanisms, see Schuurmans, Tropospheric Effects of Variable Solar Activity, Solar Physics 74: 417-419 (1981). Guess what: delta TSI, delta UV, delta heliosphere/cosmic rays, back in 1981.
Die Kalte Sonne is a modern read, page 69 being interesting. Now available in English as The Neglected Sun. Overstates the sun part, so just as wrong as the IPCC saying it is all about GHG. But more information to noodle on if one is so inclined.


[snip – no, we aren’t going there, and I’m not going to have you overrun another thread with your link bombing. Plate tectonics don’t have anything to do with this discussion -Anthony]


Rud Istvan says:
June 23, 2014 at 1:29 pm
We combined a new 10Be record from Dronning Maud Land, Antarctica, comprising more than 1,800 data points with several other already existing radionuclide records (14C from tree rings and 10Be analyzed in polar ice cores of Greenland and Antarctica) covering the Holocene. Using principal component analysis, we separated the common radionuclide production signal due to solar and geomagnetic activity from the system effects signal due to the different transport and deposition processes. The common signal represents a low-noise record of cosmic radiation, particularly for high frequencies, compared to earlier reconstructions, which are only based on single radionuclide records. On the basis of this record, we then derived a reconstruction of total solar irradiance for the Holocene, which overall agrees well with two existing records but shows less high-frequency noise. A comparison of the derived solar activity with a record of Asian climate derived from δ18O in a Chinese stalagmite reveals a significant correlation. The correlation is remarkable because the Earth’s climate has not been driven by the Sun alone. Other forcings like volcanoes, greenhouse gas concentrations, and internal variability also have played an important role. To quantify the solar influence on the Earth’s climate and to distinguish between the different forcings, climate model simulations are required for the Holocene, employing the new dataset of total solar irradiance. The dataset will be available online at the National Oceanic and Atmospheric Administration paleo server (

kadaka (KD Knoebel)

jpatrick on June 23, 2014 at 1:14 pm:

Underlying this work is the unstated presumption that sunspots are correlated with solar output. Is that true? How could we know?

You compare TSI (Total Solar Irradiance) and SSN (Sun Spot Number):
TSI is everything in the electromagnetic spectrum so use it for solar output. Just before 1979 is the start of this TSI dataset, using measurements. There are various TSI “reconstructions” that go back further. However, they get based on the SSN records which go way back before 1979, so comparisons aren’t helpful, you’ll be comparing SSN to a product of SSN.

Kirkby’s 2008 survey paper cites a bunch of stuff. One study he highlights is Mangini et al. 2005, “Reconstruction of temperature in the Central Alps during the past 2000 yr from a δ18O stalagmite record.” Excerpt from Mangini:

“… a high correlation between δ18O in SPA 12 and D14C (r =0.61). The maxima of δ18O coincide with solar minima (Dalton, Maunder, Sporer, Wolf, as well as with minima at around AD 700, 500 and 300). This correlation indicates that the variability of δ18O is driven by solar changes, in agreement with previous results on Holocene stalagmites from Oman, and from Central Germany.”

Kirkby’s Fig. 2:

Caption: Comparison of variations during the last millennium of a) temperature (with respect to the 1961–1990 average), b) galactic cosmic rays (note the inverted scale; high cosmic ray fluxes are associated with cold temperatures) and c) glacial advances in the Venezuelan tropical Andes near Lake Mucubaji (8deg 47’N, 70deg 50’W, 3570 m altitude).

D. Cohen

If you average the winter severity index over, say, a century-sized interval and then plot that average against its center point, I bet the coincidence in time becomes more remarkable. (So, for example, the “smoothed” severity index for 1650 would be the average from 1600 to 1700, the smoothed index for 1651 would be the average from 1601 to 1701, and so on). Granted, there are isolated up spikes near and inside the colored bars, but they are isolated — and the century-long averaging will tend to point this out.
Also, as a bit of a quibble, how severe was a dry — that is, little snow — but very cold winter recorded as being? If the amount of snow made more of an impression back then, since there were few or no thermometers, it’s quite possible that the winter severity index, like tree rings, records a combined precipitation and temperature impression of the climate.

Don Easterbrook

You’ve shown that the Lamb winter severity index doesn’t make a very good match with solar minima, but that doesn’t necessarily mean that the solar correlation with climate is wrong—it might as well mean that the Lamb index isn’t a good measure of what climate was doing during the Maunder. So I took a look at the CET, extended back to 1538 by Tony Brown. What I see is a temperature maximum at 1650 dropping continuously to a low at 1700-1710. It’s as good (or better) a match as one could expect.
Both 10Be and δ14C show significant maximums during the Maunder, as well as for the Sporer, Dalton, and the 1880-1915 cool period.
The CET during the Dalton shows low temps during the entire interval, (extending beyond the Dalton limits). Like the Maunder it also shows significant 10Be and δ14C maximums.
The consistent relationship between solar minima, temperature, 10Be, and δ14C maxima would seem to indicate that it’s more than just coincidence. What I make of this is that the sun is driving climate, but not at 11-yr intervals or any other cyclic interval. It seems to be ongoing, but somewhat irregular and not likely to show up in any kind of regular cycle analysis. What is especially interesting are the 10Be, and δ14C maxima that match the solar minima and temperature records, suggesting an increase in cosmic radiation during the colder periods. This would lend credence to the Svensmark hypothesis.
I doubt that you will find any kind of regular, cyclic repetition in these data, but that doesn’t mean that the sun isn’t driving the climate.

See also Kirkby’s graph of Bond’s study of ice-rafting debris vs. cosmogenic isotopes (from p.10 of Kirkby’s 2009 PowerPoint):

Not displaying for some reason. Image here:

Trond Arne Pettersen

The variability in TSI is far to small to make a difference in earth temperatures more than a tenth of a degree Celsius. BUT, from NASA:
…While total solar irradiance changes by 0.1 percent, the change in the intensity of ultraviolet light varies by much larger amounts, scientists have discovered. Research shows such variations in the Sun’s emissions can affect the ozone layer and the way energy moves both vertically and horizontally through the atmosphere….
So why not do it simple Willis. On the following graph there is a 11 year mean on both HadCRUT4 and TSI from 1850 until today. There seem to be an astonishing relation between the sun’s irradiance and the global temperature. But something seem to happen in the 1980s….
I find it intriguing. What do you think?


Although it wasn’t called the little ice age until the 1930’s, the effect had been known for centuries before that. I think it is a mistake to attribute it to eddy or lamb. Numerous writers have referenced it in past centuries. Charles dickens noticed the effect having been born during the very cold period at the start of the 19th century and lived to see some very warm periods.
Here are the CET figures for each season from 1659. Cet was thought by many scientists including lamb, Hulme and the dutch meteorological service to be a reasonable proxy for at least the northern hemisphere
In 2011 I wrote this article which extended cet to 1538. In it i Compared the temperature reconstructions of both Hubert lamb and Michael Mann.
I am currently extending it further to 1086 .There are numerous references to the cold and warm periods made over many hundreds of years. The little ice age is much more episodic than is generally believed. The period from 1500 to 1550 looks likely to be at least as warm as today. The 1730’s were only fractionally cooler. this period convinced Phil jones tha natural variability was much greater than he had previously believed.
Some of the sunspot minima match up well with colder temperatures,others do not. I remain unconvinced but it’s certainly a better match that co2 .Almost certainly the jet stream shifted as did the direction of winds. We had long periods of blocking highs and the weather during the cold periods and the transition in the 1200’s was often very extreme,


I have been coming to the conclusion that while the sun is the engine that drives our earths climate that it’s fluctuations are not enough to account for the long term climate changes. It is clear that some major factors even out the small variations and likely the biggest is the sea acting as that regulator that keeps climate stable. By the same token it is clearly arrogance that claims that humans can do what the sun isn’t doing and drive massive changes in the climate. Clearly as with the sun the changes will be small.
It is also clear that we need a lot more good solid research to have a handle on how climate really functions.

Thanks, Willis.

Dave the Realist

so I guess this is suppose to stimulate a discussion?
square root of minus 1 . LMAO


I didn’t see your reply when posting mine.
I agree that the sun certainly has an impact and arguably the period around 1650 to 1700 displays a possible sun spot relationship although other things might also have had an effect.
I think lamb is wrong to attribute the start of the little ice age to 1500AD and we are not helping our understanding of that period by believing the period from say 1300 to 1850 or so to be one
Long deep freeze. The lia had numerous very warm periods and the extremely cold periods were generally fairly short lived although they occurred fairly often.
Sun spots? Long periods of no sunshine? Long periods of extended sunshine? Jet streams? At present we don’t know the causes of the loa, but whilst we have this intriguing period when temperatures were much warmer than today and much cooler than today, with the biggest hockey stick occurring in the period 1690 to 1740, it is certain that natural variability is much greater than mann’s hockey stick would have us believe.


A simple regression model of the TSI averaged over the previous 11 years as the single and only independent variable can predict the temperature with an r-squared of 0.61 Used to predict the past 15 years or so from data it has not seen makes predictions that are more skillful than any GCM model. Its really all that simple. It works. ‘Nuff said. Perhaps we will all understand all the things that go into making it work, but for that, we will have to stop the grantsmanship of the CAGW crowd and fund on merit.

Tom in Florida

Teddi says:
June 23, 2014 at 1:26 pm
“Willis – turn off the Sun and then check the temperature. Anyone who assumes the Sun is not the main driver is “over-analysing” the simple reality that without the Sun we might as well be Neptune.”
The argument is whether small CHANGES in the Sun’s output match up with CHANGES in Earth’s climate.