Scottish Sunspots

Guest Post by Willis Eschenbach [See Update At End]

In a recent post, Anthony published Leif Svalgaard’s new paper showing 9,000 years of reconstructed solar activity.

Svalgaard paper: Reconstruction of 9000 years of Solar Activity

In the discussion, someone pointed out that the “Maunder Minimum”, a time of very low solar activity, corresponds with the coldest decade in a long-term reconstruction of summer temperatures in Scotland. Their temperature reconstruction is based on a group of pine tree-ring records spanning 800 years. Their graph is shown below:

As you can see, the period around 1690 is extremely cold. This was put forward as support for the idea that sunspot cycles affect the temperature. The idea is that when sunspots are low, temperatures are low as well. And the year 1690 is during the Maunder Minimum, a time of low sunspots.

However, as you may know if you follow my work, I like to take the largest look at the longest data that I can find. So rather than build a theory based on one decade of cold temperatures lining up with one sunspot minimum, I decided to compare the two graphs shown above. I first “standardized” both datasets, meaning that I set each of their averages to zero and each of their standard deviations to one. That allows us to compare them directly. Here is that result:

Now, the commenter was indeed correct that the low temperature in 1690 was during the Maunder Minimum.

However, the other minima do not line up with much of anything. The Wolf Minimum occurred during not just a warm period, but during the warmest period in the record. Similarly, the Sporer Minimum occurred during the warm period just before the drop to the “Little Ice Age” of the 1600s.

Then we have the Maunder Minimum. Temperatures started dropping about 150 years before the start of the Maunder Minimum, and during the first hundred years of dropping temperatures the sunspots were increasing. So obviously, the sun was not the cause of the drop in temperature.

Next, although the Dalton minimum occurred during a cold period. temperatures started dropping some seventy years or so before the start of the Dalton minimum … and temperatures warmed from the start to the end of the Dalton Minimum.

Finally, in recent times, you can see that sunspots started decreasing about 1980, while temperatures have risen during that time.

I leave the reader to draw the obvious conclusions regarding sunspots and Scottish temperatures …

[UPDATE] Some folks in the comments have said that the Scottish pine series is just as bad as many of the other tree ring series, such as those abysmal creations of Michael Mann et ilk …

However, this doesn’t appear to be the case, viz:

So while it is true in general that trees are not thermometers … when handled properly, they do appear to do a reasonable job of recording thermal variations.


PS—When you comment, please quote the exact words that you are referring to, so that we can all understand what you are discussing.

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Joel O'Bryan
October 28, 2018 11:17 pm

Tree-mometers from the past… hah!!!

They make good firewood and violins. That’s ‘Bout all.

John Tillman
Reply to  Joel O'Bryan
October 28, 2018 11:37 pm


Yes, tree rings are far from ideal as temperature proxies, although cooler is also often associated with drier and windier.

But better proxy data show that globally, solar minima are associated with colder weather and climate.

John Tillman
Reply to  John Tillman
October 28, 2018 11:53 pm

For instance:

The ‘Little Ice Age’ in the Southern Hemisphere in the context of the last 3000 years: Peat-based proxy-climate data from Tierra del Fuego

The so-called ‘Little Ice Age’ (LIA) of the 15th to 19th centuries ad is well-attested from much of Europe and from some other parts of the Northern Hemisphere. It has been attributed to solar forcing, associated with reduced solar activity, notably during the Spörer, Maunder and Dalton solar minima, although other causes have also been proposed and feature strongly in recent papers. Detection of the LIA in some proxy-climate records from the Southern Hemisphere is less clear, leading to suggestions that the LIA was perhaps not a global phenomenon. Resolving this issue requires more data from the Southern Hemisphere. We present proxy-climate data (plant macrofossils; peat humification) covering the past three millennia from an ombrotrophic mire (peat bog) in Tierra del Fuego, southern South America, but focus our discussion on the period traditionally associated with the LIA. During parts of this time, the mire surface was apparently relatively dry compared with much of its 3000-year record. It was reported earlier that a particularly dry episode in the mire coincided with the 2800 cal. BP ‘solar’ event (since identified as a Grand Solar Minimum), which was attributed to solar-driven changes in atmospheric circulation, and more specifically to a shift in position of the Westerlies. Parts of the LIA record show a similar shift to dryness, and we invoke a similar cause. The shifts to and from dry episodes are abrupt. These new data support the concept of a global LIA, and for at least the intense dry episodes might reinforce the claim for solar forcing of parts of the LIA climate.

Greg Goodman
Reply to  John Tillman
October 29, 2018 4:50 am

I leave the reader to draw the obvious conclusions regarding sunspots and Scottish temperatures …

I do not see any data of Scottish temperatures , just tree growth. I thought Briffa’s data blew that one out of the water , decades ago ( before it got cropped to “hide the decline” ).

John Tillman
Reply to  John Tillman
October 29, 2018 2:15 pm

A paper this year reconfirmed the appearance of alternating warm and cold intervals in Arctic sea ice extent. During the Holocene Climate Optimum, which ended about 5 Ka, it practically disappeared in the summer.

Today’s extent has pulled back slightly from during the LIA, but it still far above that of prior warm intervals, such as the Medieval, Roman and Minoan WPs.

Please see especially the last graph, from the 2018 study:

Glaciers paint the same picture. For New Zealand, max extent came ten to 15 years after the end of the Maunder. During the 17th century, alpine villages were famously threatened by the glaciers advancing under solar minimum conditions.

Reply to  Joel O'Bryan
October 29, 2018 11:44 am

The wood for Stradivarius violins grew during the Maunder Minimumm and it has been hypothesized that this led to its superior tonal qualities.

John Tillman
Reply to  Taphonomic
October 29, 2018 11:52 am


That hypothesis has stood up well.

Dendochronologists have also been called upon to date a variety of musical instruments.

Reply to  Taphonomic
October 29, 2018 3:49 pm


From your link.

Instruments produced by the master violinmakers of the late 17th and early 18th centuries are reputed to have superior tonal qualities relative to more contemporary instruments. Many hypotheses have been proffered to explain this difference in sound quality, but all hypotheses were found wanting. We propose an alternative hypothesis based on the unique climate situation that existed between AD 1645–1715 known as the Maunder Minimum.”

Wood used for lutherie, including violins varies in annual wood growth rings per inch (2.54 cm) of wood. Ten growth rings per inch is normally considered poor quality for lutherie purposes.
Fourteen or more growth rings per inch (2.54 cm) is when wood for instruments is believed to be reaching desirable quality.
Twenty or more growth rings per year may be considered “master” quality wood.

Antonio Stradivari lived from 1644 through 1737.
Ignoring Antonio’s years of apprenticeship or journeyman, that places his earliest best instruments as occurring after 1670.

Instruments made by Antonio have been identified with as few as 12-14 growth rings per year but often greater. Heartwood is preferred with sapwood being avoided. This removes approximately two inches (5 cm) of the most recent growth before the tree is felled and split.
The sapwood is not discarded, instead it is used for reinforcement and tentallones, especially where an instrument’s corners are glued.

At 12 growth rings per year, trees harvested in 1670 would have 5.8″ (14.7 cm) of wood grown during the 1600s, with two of those inches unusable for a violin’s main sound plates.
At 20 growth rings per year, trees harvested in 1670 would have 3.5″ (9 cm) of wood grown during the 1600s. And two of those inches are unusable for instrument tone plates.

At one f the smallest instruments Antonio constructed, a violin requires a thoroughly aged tonal plate 5.5″ (14 cm) to 6″ (15.2 cm) in width. Even these are split thinner, jointed then glued together to form the top and back plates.

Add in the two inches of sapwood, and the tree harvested for wood needed to grow a minimum of 90 years for the lower quality 12 growth lines per inch (2.54 cm) and 150 years for better quality wood with 20 or greater growth lines per inch (2.54 cm).
That places tree growth periods as:
Tree harvested; 1660.
Tree Growth, 12 annual rings per inch (2.54 cm); 1570 – 1660
Tree growth, 20 annual rings per inch (2.54 cm); 1510-1660.
N.B. that the heartwood for the better quality wood grew before the Maunder Minimum started to get cold!

Violins were the smallest instruments. Violas, Bass violas, Guitars, etc. all required much larger wood.

Thoroughly aged often meant a decade or more.

Looking at the science abstract again;

Instruments produced by the master violinmakers of the late 17th and early 18th centuries are reputed to have superior tonal qualities relative to more contemporary instruments. Many hypotheses have been proffered to explain this difference in sound quality, but all hypotheses were found wanting. We propose an alternative hypothesis based on the unique climate situation that existed between AD 1645–1715 known as the Maunder Minimum.”

Once again, gross assumptions are promoted to causation.

If, the Maunder Minimum theory is correct, then Antonio Stradivari’s students, apprentices and journeymen would have produced the finest instruments. Even besting Antonio’s instruments.

Historically, Antonio Stradivari and many contemporary, past and current luthiers have availed themselves of opportunities to search old dry wood piles for suitable wood for their instruments. i.e. any opportunity to find quality wood for instruments was used to full advantage.

Carleen Hutchins did a lot of work investigating what makes for good tone quality in wood. Long term aging proved beneficial, the longer the better. But, a luthier’s skill proves paramount!

Rich Davis
Reply to  Joel O'Bryan
October 30, 2018 3:36 am

John Tillman commented on a recent post in which Anthony published Leif Svalgaard’s new paper. In his comment, John pointed out that the Maunder Minimum corresponded with coldest period in the temperature record, which John took as evidence that solar minima lead to cold periods. Someoneposted a rebuttal to that comment. Their premise was that the same tree ring series that John had used as evidence would falsify the theory. They claimed that in particular, the Wolf minimum corresponded to the highest temperatures in John’s proxy record. After some back and forth with John, they posted a chart comparing the original tree ring series to the Central England Temperature record.

Just summing up! 🙂

John Tillman
October 28, 2018 11:28 pm


You’ve used an old dating of the Spörer Minimum (Eddy, 1976). As the revised sunspot curve shows, its’ now dated from c. AD 1420 to 1570, if not indeed from 1400. The Scottish data confirm what had already been observed in China (Jiang & Xu, 1986), ie that the period 1430-1520 (starting slightly before the traditional date of the Sparer) was indeed colder than average there, but the period 1520-1620 (the second half of the minimum) was warmer than average.

On the Spörer Minimum

In this paper we have examined the real behaviour of solar activity during the period AD 1400–1600. The results are as follows: (1) the distributions of the 20 naked-eye sunspot records are inhomogeneous. There are 2 sightings in the 15th century and 18 sightings in the 16th century; (2) the distributions of auroral records are similar to sunspot. There are 33 records in the 15th century and 315 records in the 16th century; (3) the climatic fluctuations in China shows that the period AD 1430–1520 was cold while the period AD 1520–1620 was warm. These facts clearly demonstrate that the Spörer Minimum, if it extended from AD 1460 to 1550, could be a specious results and it, if its extent was AD 1400–1510, is a real feature of solar variability in that time.

Similarly, there is a lag in the response in Scotland to the Wolf Minimum, with the cooling occurring after its onset. So cooling happened in each of the minima, ie the Wolf, Spörer, Maunder and Dalton, but not always during the entire period of low solar activity.

The same correlation is found in observations from around the world.

John Tillman
Reply to  Willis Eschenbach
October 29, 2018 12:03 am


Not circular reasoning, but an observation. The fact is that during each of those solar minima, earth cooled.

Naturally, there are other things going on in the climate system besides solar activity, and still other factors which modulate insolation and other effects of the sun.

But, as noted, all over the planet, all or parts of major solar minima are associated with cooling. It could be a coincidence, but there are well supported mechanisms by which periods of low sunspots plausibly could lead to global cooling, and to changes in oceanic and atmospheric circulations which would produce drier conditions in some latitudes and wetter in others.

Reply to  Willis Eschenbach
October 29, 2018 8:05 am

Any complex, non-linear chaotic system can show a “lag”, or perhaps more properly a cumulative response to a small initial input.

John Tillman
Reply to  Willis Eschenbach
October 29, 2018 12:15 am


Not special pleading, but again, an observation.

Different regions are affected differently by the effects of lowered solar activity. As noted for instance with the Fuegian peat bog study, a generally cooling Earth moves precipitation bands around. It’s not just lags, but changes in flow patterns.

So that parts of the solar minima in some areas show different effects shouldn’t be a surprise or taken to invalidate the conclusion that solar minima affect climate.

Jaap Titulaer
Reply to  Willis Eschenbach
October 29, 2018 5:38 am

>> First, you say Sporer is from 1420 to 1570. I used 1460 to 1550. That’s a difference that makes no difference. It’s still occurring during the warm period prior to the temperature drop down to the Little Ice Age.

That warm period was already over. There was a short return to warmer weather before proper start of the LIA in ca 1650, but the MWP ended by ca. 1425.

The cold period started again shortly after 1400 as we can tell based on Greenland.
The Western Settlement was abandoned sometime between 1350 and 1375 (with stragglers until 1400), the Eastern (southern) Settlement closer to 1425 or even as late as 1450, but in fact we have very little after 1400. Sure a few may have survived on seal flesh & otherwise living as Inuit

The last record of a marriage is from 1408. The last known bishop left ca 1378, but we also have a report of at least one other bishop who probably died ca 1418 due to an attack by Skraelings.
It is true that the pope instructed the Icelanders to provide the Greenlanders with a new bishop as late as 1448, but that never happened.

By the early 15th century the diet has already changed dramatically and people are leaving.
” In the late settlement period in the fi rst half of the 15th century AD, however, up to about 80% of the food of some Norse Greenlanders was of marine origin (Fig. 1; Arneborg et al. 1999, Lynnerup 1998). ”

By that time farming & the warm period for Greenland is over.
That (c.1425) marks the proper end of the MWP. There was a cold period and thereafter a temporary return to warmer weather before the LIA starts.

>> “the climatic fluctuations in China shows that the period AD 1430–1520 was cold while the period AD 1520–1620 was warm”

Same for Europe AFAIK. Cold starts 1425 (and MWP is over), warm again by? 1550, then start of LIA ca 1650.

Of course some studies show the MWP end even earlier, but at least the Greenland situation is exactly dateable via documents.

In any case I very much doubt that one could qualify the period after 1425/1450 ‘warm’. Never seen that in any of those studies. And earlier end of MWP (late or even mid 14th century) perhaps, but not later than mid 15th.

Lake Neuchatel in Switserland gives the typical picture (follow this link in case the picture does not show):

Clyde Spencer
Reply to  Willis Eschenbach
October 29, 2018 9:49 am

Look, a three minute lag with the same input! 🙂

October 28, 2018 11:30 pm

The problem here is interpreting tree rings as temperature proxies. They are not. They are also rainfall proxies and fertilization proxies. For example, if a herd of deer froze to death and died in a forest, they would fertilize the soil and result in more growth even if the weather was colder or drier. In order to use tree rings as temperature proxies you have to locate a spot where you believe that temperature is the ultimate constraint on growth. Altitude is not a good indicator, either since CO2 fertilization can greatly influence treeline and water loss (more CO2 means fewer stoma which results in better drought tolerance).

Tree rings are fairly useless as temperature proxies except at the very margins of forest growth a extremely high latitude (tundra margins).

John Tillman
Reply to  crosspatch
October 28, 2018 11:42 pm


In the comments to Leif’s presentation, I commented that the 1690s were the coldest decade of the LIA and Maunder Minimum in the CET. Willis objected to the CET’s reconstruction of temperature, so I cited both the Scottish study and another from New England, supporting the conclusion that that decade was indeed unusually cold, as also was the first decade of the 18th century.

After the Maunder ended, the world warmed rapidly. The early 18th century warming in the CET was greater in amplitude and lasted longer than the late 20th century warming. Adjustments to the CET might have changed that however. I haven’t checked lately.

But in any case, when the sunspots returned, so too did warmth on Earth.

Reply to  crosspatch
October 29, 2018 5:29 am

Correct. After M&M’s demolitions of tree ring proxies for temperatures, why anyone would revisit this discredited territory is beyond me.

Reply to  crosspatch
October 29, 2018 8:07 am

I am pretty sure the whole “hide the decline” debacle shows the problem. Either Mann’s modern temperatures are not just wrong but going in the wrong direction, or trees are a rubbish proxy.

Pop Piasa
Reply to  Phoenix44
October 29, 2018 8:43 am

Maybe some of both?

October 28, 2018 11:36 pm

The analysis of Willis clearly demonstrates that temps and sunspots are two
different shoes, which do not fit…..
But this is not the whole story: Take the 9,000 yr Wu graph and focus onto
all maximum peaks of the 9,000 yr reconstructed SN, and compare those peaks to the temps of GISP2, Alley 2004 …and you will recognize that all SN peaks are placed in such a way that all temps always DROP after each SN high peak.
Willis, check it out.
This contradicts Willis and the Scottish temp graph.
The temps since 1600 AD do not follow the SN number, rather Earth orbital
parameters, see: Part 8 in Climate patter recognition (1600 AD .2050 AD) in

R Fujii
October 28, 2018 11:54 pm

Hi Willis. Always enjoy your writings, but I do have a slight gripe with your statement:
So obviously, the sun was not the cause of the drop in temperature.

One CAN say “the SUNSPOT COUNT was not the cause of the drop in temperature.” The sun varies in ways some of which we are just beginning to understand ( ex: ). I don’t think we even have a firm grasp on what changes even the known variations of the sun causes within the biosphere ( to say that the sun’s changes has zero effect would be ignoring Newton’s third law), so it’s premature to say the sun isn’t the cause.

Pop Piasa
Reply to  R Fujii
October 29, 2018 8:54 am

We also don’t have a grasp on how the oceans deal with the insolation they recieve. How long does it take for solar energy to be released, once absorbed? Trying to correlate land temperatures to solar activity requires complete understanding of oceanic processes if it is to be valid.
Certainly tree ring are affected by other factors than just temperature, so they are the poorest proxy one can choose, unless one desires something easily “fudgeable”…

Samuel C Cogar
Reply to  Pop Piasa
October 30, 2018 6:48 am

Pop Piasa – October 29, 2018 at 8:54 am

How long does it take for solar energy to be released, once absorbed? Trying to correlate land temperatures to solar activity requires complete understanding of oceanic processes if it is to be valid.

Right you are, Pop Piasa.

And a good place for the novice to begin their “understanding” is with the Gulf Stream.

Those Solar irradiated “warm” waters originate in the Gulf of Mexico and then flow around Florida and all the way up the east coast of North America and then across the North Atlantic where it still has sufficient thermal (heat) energy to keep parts of norther Europe from “freezing” up solid during the Northern Hemisphere winters.

The near-surface temperature in Scotland is directly affected by the warm waters of the Gulf Stream. So, the big question is, …… iffen the lack of Sunspots causes a “cooling” of the near-surface atmosphere, how long would it take before the “cooled down” waters of the Gulf of Mexico start causing a “cool down” of the Scottish near-surface air temperatures? Five years, 25 years, 100 years, 500 years?

The Gulf Stream is typically 100 kilometres (62 mi) wide and 800 metres (2,600 ft) to 1,200 metres (3,900 ft) deep” …… which means there is a humongous amount of “warm water” that will take quite awhile to cool down enough to start effecting air temperatures in northern Europe.

October 29, 2018 12:19 am

–Finally, in recent times, you can see that sunspots started decreasing about 1980, while temperatures have risen during that time.

I leave the reader to draw the obvious conclusions regarding sunspots and Scottish temperatures … —

Well, I don’t think sunspots are a control knob.
In terms of any kind of control knob, I would have to pick the Milankovitch cycles- but they don’t really work as control knob but most of time they have pattern and they could cause large variation in global climate.
And what mean by large variation, they seem to control the ocean average temperature.
And in our icebox climate, the average ocean temperature has range of about 1 to 5 C. And currently the average ocean temperature is about 3.5 C.
The average temperature of ocean is another strong control knob. If average ocean is 2 C, that is glacial period. If 4 C that is interglacial period- or can’t be a glacial period.
The average ocean temperature is control knob of the average ocean surface temperature. Our current average ocean temperature is about 17 C.
Now, ocean of 3.5 C doesn’t make the average ocean surface 17 C, but rather, it might keep in a range of say 16 to 18 C. Or to have average surface temperature of 15 C, it seems the ocean would need to about 3 C or colder.

So what makes earth average temperature of about 15 C, is average ocean surface temperature of about 17 C and average land surface air temperature of 8 to 11 C.
And currently our average land surface air temperature is about 10 C- a century ago is seems to have been around 9 C and a few centuries ago would be 8 C [or cooler].
If ocean surface temperatures increase from about 17 C to 18 C, it will have large effect upon average land temperature- say range of a global average land surface temperature of 10 to 13 C.

But average ocean or average ocean surface temperature has little effect upon the tropics [ocean surface or land surface air]. The tropics tends to have fairly constant average temperature and it’s 40% of earth surface area. Or this quite different than the greenhouse effect theory would indicate, where idea seems to suggest tropics must warm or cool in order to effect global average temperature {hotspot at tropics, etc].

So I think sunspots are most going to effect regions outside of the tropics and it’s not a control knob. And generally no sunspots for decades is mostly about weather effects and average land surface temperatures, and basically any effect of any kind require centuries to change global average temperatures, which tied to average ocean temperatures [it would take a long time to warm or cool our 3.5 C ocean].

From such a view, I do see a relationship regarding sunspots and the Scottish temperatures.

John Tillman
Reply to  gbaikie
October 29, 2018 12:50 am


Milankovitch cycles affect insolation, ie how solar output strikes the planet. The orbital and rotational mechanical cycles do clearly affect Earth’s climate system.

Both in glacial and interglacial intervals, there are also climatic effects deriving directly from variation in solar radiation and magnetic flux. There probably isn’t a single control knob on climate, but the climatic effects of solar variations aren’t trivial, and show up in the proxy records.

Warming since the PDO flip of 1976-77 hasn’t been out of the ordinary, and the trivial drop in sunspots since late in the last century hasn’t yet reached levels which historically have shown important climatic effects. Should they keep dropping, we might suffer a Dalton Minimum grade cooling, but we’re a long way from Maunder levels, when the sun was spotless not for part of one ~11-year cycle, but for decades.

The Modern Warm Period since the end of the LIA Cold Period should last at least another century. Let’s hope it does, anyway. Some think that the alternating centennial-scale cold and warm intervals are getting shorter, heading into the next big ice age in a few thousand years (or so, if, as Javier argues, the Milankovitch axial tilt cycle rules), which would be a bad thing.

Reply to  gbaikie
October 29, 2018 12:58 am

Of course UK [and Scotland] are in an oceanic climate:

One should more temperature change [regarding sunspots] in non oceanic climates. Like say, most of Canada.

Stephen Wilde
October 29, 2018 1:13 am

The only point that Willis is making is that the colder spells do not always neatly line up with low sunspot numbers.
He has been told repeatedly that the reason would be oceanic thermal inertia which sometimes supplements and sometimes offsets solar influences.
Yet he pretends persistently that no such mechanism has ever been suggested to him.

Greg Goodman
Reply to  Stephen Wilde
October 29, 2018 5:02 am

Any attempt a pretending a single variable will explain climate will quickly fall apart. Be it CO2, SSN or anything else.

The closest I’ve seen to date in Vuk’s lagged geomagnetic plot, but I don’t recall seeing and data to reproduce/validate his graphs.

If you are saying OHC acts as a damper , it should be possible to apply a suitable ( asymmetric ) kernel to SN to account for it. If you are saying ocean heat has its own variability then some data for how to combine the two would be needed to back up the claim.

Here is what happens if you apply an exponential decaying kernel to the latest SN messenger.
comment image

Reply to  Greg Goodman
October 29, 2018 7:09 am

Greg, I uploaded data file for you on my website and said so in reply to your relevant comment. I may have taken it down after few days or at least I said I would do. Since I am away from home for the most of next month if file isn’t still there get in touch during the last week of November and I’ll email it to you.
Dr. Archibald asked for source, I told him how to get data ( see his last SSN review), he never came back so my next comment there needs a /sarc added.

Reply to  Greg Goodman
October 29, 2018 7:13 am

BTW, here is link to graph GG referred to:

Reply to  Stephen Wilde
October 29, 2018 5:33 am

That’s not how I read it. My reading is that Willis believes tree ring are a valid proxy for temperatures. I stand to be corrected, but that’s what I see.

October 29, 2018 1:15 am

My thoughts. First, the growing season in Scotland is only May to September, so tree ring proxies are not representative of average annual temperatures. Scotland sits in a zone where mild maritime winds mix with colder arctic air in the north, and coninental air in the east. Our weather is largely dictated by jet stream flctuations, and moderated by the relatively mild North Atlantic Drift, or \gulf Stream. Our weather is highly variable, and by weather I mean daily, weekly, monthly, seasonally, yearly, and even on decadal scales. For exampe, we had a long run of mild winters in the 1990s and early 2000s, which helped convince many people (who should have known better), that we were experiencing global warming, even though summer temperatures during these decades were if anything cooler than average. The 1690s were indeed a disastrous decade for many parts of rural Scotland, where a run of cold summers and failed harvests led to mortality of 1/3rd of the population directly from starvation or malnutrition related diseases. Iirc, volcanic activity in Iceland has been blamed for at least two of these summers. I would suggest that it is mostly random natural variabilty in the Scottish pine cone proxies, where any solar signal will be lost in the noise. I would also suggest that any measurable climactic effect of sunspot cycles is much more likely to be found in tropical/mid latitude cloud cover data.

Samuel C Cogar
Reply to  lapogus
October 30, 2018 7:22 am

lapogus – October 29, 2018 at 1:15 am

The 1690s were indeed a disastrous decade for many parts of rural Scotland, where a run of cold summers and failed harvests led to mortality of 1/3rd of the population directly from starvation or malnutrition related diseases.

No surprises there, according to this temperature proxy graph, …… the 1690’s was the coldest part of the LIA.

October 29, 2018 1:58 am


Scotland? Sun? Naaaahhhh…….

(Disclaimer: I spent a week home in the Campsie hills this summer. 25°C and glorious sunshine, it didn’t last).

According to Paul Holmwood on notalotofpeopleknowthat Scotland is the only place in the UK where rainfall has increased during our ‘AGW’ period. I would question that as I’m not sure how much more rain could fall in Scotland without entirely obliterating the week long summer it occasionally gets.


Reply to  HotScot
October 29, 2018 5:15 am

LOL, my thoughts exactly. Scottish sunshine is an oxymoron 😉

Clyde Spencer
Reply to  HotScot
October 29, 2018 10:18 am

A whole week? Vermonters have long claimed that Summer comes on July 4th and leaves on July 5th! At least it doesn’t stick around long enough to wear out its welcome. But, then there was the year that New England didn’t have a Summer, when it started snowing again in June.

Did Scotland experience anything similar?

Samuel C Cogar
Reply to  Clyde Spencer
October 30, 2018 7:27 am

HA, when I fist moved to upstate NY they told me they only had two seasons, ….. winter and 4th of July.

Jaap Titulaer
October 29, 2018 2:02 am

>> I leave the reader to draw the obvious conclusions regarding sunspots and Scottish temperatures …

Uhm, that those are not temperatures?
But a mixture of various other influences + a bit of temperature?

Reply to  Jaap Titulaer
October 29, 2018 5:13 am


October 29, 2018 2:08 am

Looking from eye, there are 7 periods that correlate and 4 that do not. The chance of getting 7 heads out of 11 coin throws is about 15% or 1 in 6. Since you would have claimed a “relationship” if it had been anti-correlated or correlated, then the chance of claiming a “relationship” is 2 in 6. If I then factor in the “Ned” type selection of different graphs, periods,etc – the fact people try numerous metrics to try to find one and only report those with some kind of “fit”, the result is close enough to chance that it is not significant.

As for the 1690s – there’s a very expensive book called “the ill years” in which it gives various accounts of the deaths in Scotland with estimates of around 1/3 to 1/5 of the population dying. One illustration of this is that dead bodies were just left lying in the street.

The direct result was to cause Scotland to wish to join with England and create the greatest empire the world has ever seen. But for obvious reasons, Scottish nationalists (who hate the English) now ignore the 1690s which was the greatest calamity in recorded history in Scottish. That’s because it can’t be blamed on the English.

Instead nationalist go on about the so called “Highland clearances” – a period after Scotland joined with England and so the “genocide” as the SNP call it can be blamed on the English. How I could only find one death securely linked to the clearances (and that went to court). And to prove this “genocide” is baloney during the clearances the Highland population grew.

The 1690s was a real disaster for Scotland and undoubtedly responsible for the desertification of many places (which are usually blamed on the later “highland clearances”). But the reason the 1690s mass deaths have been obliterated from normal history in Scotland is because it isn’t politically convenient to nationalists in academia. In other words, like Global Warming “science” academia is yet again telling lies because it doesn’t fit their politics.

Reply to  Mike Haseler (Scottish Sceptic)
October 29, 2018 4:39 am

As if “weather” drives civilization, the big lie of the 21st century. Robert Dundas, the hated Lord Advocate of Scotland, whose clearances of the Scottish Highland population inspired the phrase “sheep eat men”.

The only answer to such sophistry is Rober Burns :

What force or guile could not subdue
Thro many warlike ages
Is wrought now by a coward few
For hirling traitor’s wages.
The English steel we could disdain,
Secure in valour’s station;
But English gold has been our bane –
Such a pacel of rogues in a nation!
– Robert Burns
Such a Parcel of Rogues in a Nation

There is a parcel of rogues right now trying to remove Trump and restart the jolly British Great Game of Mackinder again.

Reply to  Mike Haseler (Scottish Sceptic)
October 29, 2018 5:18 am

A good test of this kind of thing is flip the proxy and see whether it still “appears” to correlate.

Dodgy Geezer
Reply to  Mike Haseler (Scottish Sceptic)
October 29, 2018 7:28 am

…But for obvious reasons, Scottish nationalists (who hate the English) now ignore the 1690s which was the greatest calamity in recorded history in Scottish. That’s because it can’t be blamed on the English….

Oh, they could if they tried. For instance, I have seen the failure of the Darien scheme blamed on the lack of support from the English. Briefly, the Scots wanted to emulate the English, who were establishing trading colonies at this time, and decided to move into a Spanish area in South America. The English warned them against it, and said that they could not support them because they did not want a war with Spain.

The Scots went ahead, and were duly beaten back by Spain, losing all their money in the process. Enraged at their losses, they then claimed that the English SHOULD have supported them, and went and hanged three English sailors that they found in Leith….

jim hogg
Reply to  Mike Haseler (Scottish Sceptic)
October 30, 2018 8:48 am

You style yourself as “sceptical”, Mike, which is strange, given that you haven’t been nearly sceptical enough of your own perspective on and “knowledge” of this little bit of the planet, its people and its past.

Timo Kuusela
October 29, 2018 2:16 am

Again, for a layman, it seems that sunspots is a good way and anything concerning tree ring proxies is just rubbish,and at most, “nice to know”. After all ,the whole mess is partly going on because of just one Yamal tree that happened to have a rotting reindeer close by…. Svalgaard seems to have something so clearly visible here that we can be having some real cooling in the next decade. Just like the Russians predicted.

October 29, 2018 2:41 am

Hi Willis

A couple of years ago I wrote an article I termed ‘the intermittent little ice age’ as this period was not one of constant cold, but was often highly variable

We do have instrumental records for CET covering this period (but not scotland in any depth) and I carried out a reconstruction back to 1538 so encompassing other cold periods

I think the evidence on sun spots is equivocal to say the least. I made this comment within my article

“The effect of sunspots on the climate is contentious. Looking at the data in Figure 8, it appears that the impact of the second half of the Sporer minimum on temperatures is difficult to discern. The Maunder minimum however appears to largely coincide with colder years, whilst the Dalton minimum is more mixed. However, there had been many cold years prior to the onset of these sunspot minimums and cold years returned after they had finished, so the relationship appears unproven and may be coincidental, where there is some correlation.”

I am dubious about Scottish pine records , there is a short growing season and of course they tell us nothing of the winter. Summers were often hot after a severe winter and vice versa. As a proxy I think trees are a better measure of likely precipitation than anything else and reflect the local micro climate.

Anyway, I tend to believe the sun spot scenario is overplayed


Reply to  tonyb
October 29, 2018 6:43 am

That would be my guess…..the tree rings are screwed….shift them over and it’s a perfect match

Ulric Lyons
Reply to  tonyb
October 29, 2018 6:54 am

“and of course they tell us nothing of the winter.”

Have you never heard of frost rings?

Reply to  Ulric Lyons
October 29, 2018 7:19 am

Frost rings can’t tell you for how long or how low……

Trees stop growing when it’s too hot or too cold….rings can’t tell you for how long, how high, how low

Ulric Lyons
Reply to  Latitude
October 29, 2018 3:40 pm

Frost is a great measure of how low.

Samuel C Cogar
Reply to  Latitude
October 30, 2018 8:30 am

Ulric Lyons – “Have you never heard of frost rings?

Latitude – “Frost rings can’t tell you for how long or how low……

The only place that I know of where one can find a “frost ring” is during the winter time, on the seat of an “outhouse” (outside toilet).

It’s best that you guys quit using Merriam-Webster or equivalent for your “go-to” expert, to wit:

Definition of frost ring – false annual ring in the trunk of a tree that is often evident only as a brownish line of collapsed or abnormal cells and is caused by defoliation due to frost and subsequent leafing out again.

I believe an “insect ring” is more believable than a “frost ring”. A massive outbreak of insect larvae, such as the Gypsy Moth, can defoliate thousands of acres of forest.

But REMEMBER, once the defoliation has occurred, … you hafta wait until next Spring before any new “leafing out” will occur. That’s because trees produce their buds at the end of summer, usually in August, ….. to wit:

In most northeastern trees, the buds that burst open in spring were formed the previous summer. … They too were made last summer, but they spend the winter dormant and protected under bud scales until favorable growing conditions return in spring.

Mark - Helsinki
October 29, 2018 2:48 am

Sunspot “cycles” dont affect temperature. (They are not cycles FYI stop calling them that)

What affects temperatures is solar process iterations. Sun spots are one factor of the combine solar process iteration.

Sun spots do not tell us much about the total solar activity through each iteration of solar processes.

OK so it is interesting, and worth looking at, though looking at Sun spots are some sort of top level indicator of what the sun is and is not doing to earth’s temperatures is silly.

We need to understand what is happening along with sun spots, and the TRUTH is we largely have no idea bar theoretical and hypothetical ideas, with not so strong evidence to support them. Just because there are no better ideas, that does not mean the existing hypothesis and theories are even remotely correct.

Yes I am not contributing to an answer, but I am contributing to ruling out nonsense and looking at sun spots alone, to try find a magic link to temperatures is fools gold.

Lastly, to claim the sun is or is not driving temperature anomalies, is dopey, because we categorically do not know enough to make assertions of any weight whatsoever, this scientism is doing my head in.

Mark - Helsinki
Reply to  Mark - Helsinki
October 29, 2018 2:55 am

“Sunspot “cycles” dont affect temperature” << was meant to be in "". Sun spots are a feature, stop using features to try derive causes

Bob Weber
Reply to  Mark - Helsinki
October 29, 2018 12:06 pm

Ego doesn’t enter into the equation here.

We have strong, statistically significant evidence of solar warming since the Maunder Minimum by using sunspots and solar cycles.

We can know the sun rules the climate with absolute certainty now.

What we can’t know is if the cosmogenic reconstruction spliced onto the known sunspot record is valid.

It seems some like to use data of unknown reliability to draw their conclusions against solar forcing rather than by understanding how the sun warms/cools with the better data of the modern era.

My system is an objective data driven verified method that works with modern data.

There was a large discrepancy over time in the solar output during the Modern Maximum, compared to the previous period coming out of the mid 1800’s:

comment image

comment image

We have good data now to make definite assertions that carry weight in favor of solar forcing, discernible via sunspot numbers since the LIA.

The sun’s magnetic field controls the sunspot activity, ‘features’ as you say, and TSI:

comment image?dl=0

Mark - Helsinki
October 29, 2018 2:53 am

To make a point re my previous post.

When will scientists start to learn to say “I have no idea” or “we just dont know enough yet” when that is the truth of the matter? That is where we are re Sun and temperatures, and yet show me a paper that says “we don’t know, this is a best guess”

Ego in science, is a massive problem

Reply to  Mark - Helsinki
October 29, 2018 4:45 am

A very good impression of Sir Isaac Newton of the Royal Mint with his :

“But hitherto I have not been able to discover the cause of those properties of gravity from phenomena, and I frame no hypotheses [hypotheses non fingo],” ordained Sir Isaac in the Principia’s infamous General Scholium. “...[F]or whatever is not deduced from the phenomena is to be called an hypothesis; and hypotheses, whether metaphysical or physical, whether of occult qualities or mechanical, have no place in experimental philosophy. In this philosophy particular propositions are inferred from the phenomena, and afterwards rendered general by induction. Thus it was that the impenetrability, the mobility, and the impulsive force of bodies, and the laws of motion and of gravitation, were discovered. And to us it is enough that gravity does really exist, and act according to the laws which we have explained, and abundantly serves to account for all the motions of the celestial bodies, and our sea.”

It is quite amazing to see Newton impressionarios in the 21st Century, more than one such here.

Dodgy Geezer
Reply to  Mark - Helsinki
October 29, 2018 7:57 am

…When will scientists start to learn to say “I have no idea” or “we just dont know enough yet” when that is the truth of the matter?….

At exactly the same time when saying that they have spent a lot of money on research and they are no further ahead does NOT disqualify them from further grants.

At the moment we give free taxpayer’s money to scientists who can come up with persuasive cases for spending it. The money is conditional on the scientists delivering SOMETHING. Until we change that funding process the scientists will continue to claim that they are delivering – no matter what their research actually finds…

October 29, 2018 3:20 am

And no way is it “Settled Science”.


October 29, 2018 3:39 am

I thought Mann had to “hide the decline” because his tree rings did not line up properly with known temperatures. Would this not put into question the use of tree rings as a proxy? What is it about Scottish pines that make them reliable? Why not use CET data?

Reply to  Guy
October 29, 2018 7:02 am

Yes, that’s what Jones dubbed “Mike’s Nature Trick ” ™ , except that it was Briffa’s data he was screwing around with , not his own.

I’m rather surprised to see Willis say :

I leave the reader to draw the obvious conclusions regarding sunspots and Scottish temperatures …

… at the end of an article which does not have any temperature data but only a “reconstruction” based on tree rings.

Michael Phillip Miller
October 29, 2018 4:14 am

the significance of SUNSPOTS is that from them escape UV radiation. No sunspots = no UV radiation. Upper atmosphere heating due to increases in Ultra-violet radiation is a factor in global warming. There may be some “lag time” for the heating of the upper atmosphere after a period of low, or no, solar ultra-violet radiation.

Anthony Banton
Reply to  Michael Phillip Miller
October 29, 2018 11:55 am

“No sunspots = no UV radiation.”

Less, not “no”.

“Upper atmosphere heating due to increases in Ultra-violet radiation is a factor in global warming.”

Nothing to do with GW. The heating of the stratosphere a tad more via UV in higher sunspots has no effect on surface temps.
Just normal cyclic behaviour via interaction with O3.

“There may be some “lag time” for the heating of the upper atmosphere after a period of low, or no, solar ultra-violet radiation.”

No lag, except where in the Earth’s shadow … as is the case in the NH polar night.
Reduced UV then impacts the equatorial belt and lessens the delta T from there to the pole (Stratospheric Jet) and hence the strength of the Strat polar vortex.
This along with other bottom-up factors can lead to SSW’s (sudden stratospheric warming) events that lead to polar air excursions to more southern latitudes.
However warmer air is also drawn up into the Arctic and is just the movement of energy in the climate system. Not a net cooling.

Reply to  Anthony Banton
October 29, 2018 3:33 pm

A question. Does the variation in sun spots/UV show up in the so-called ozone hole?

bit chilly
Reply to  R2Dtoo
October 29, 2018 5:23 pm

good question r2dtoo. ren would be the man to ask.very intermittent commentator though,and doesn’t often answer questions,more makes statements.

October 29, 2018 4:33 am

That the the second half of the seventeenth century and the 1690’s in particular was an exceptionally cold interval is known from a large number of historical sources, as is the very abrupt amelioration after 1715. I particularly recommend Ladurie’s “Times of feast, times of famine” and Lamb’s “Climate history and the Modern World”, both written at a time when climate history was still a science, one by a very eminent historian and one by an almost equally eminent climatologist.

So it is not a matter of Scottish tree-rings at all. There is even an instrumental series that goes that far back, the famous CET (Central English Temperature). The less well-known Uppsala series starts in 1722, so it is too short for the 1690’s minimum, but it does show the very warm interval following in 1720’s-1730’s.

The very cold interval around 1810 (The Dalton minimum) is attested in several instrumental series (e. g. CET, De Bilt, Berlin, Uppsala, Stockholm, St Petersburg, Torneå) as well as a vast number of historical sources.

Burl Henry
Reply to  tty
October 29, 2018 5:59 am


“The very cold interval around 1810 (The Dalton minimum)”

This was caused by a VEI6 volcanic eruption circa 1809 (unknown location, identified by high sulfate levels in ice cores).

As were ALL of the other minimums.

Reply to  Burl Henry
October 29, 2018 7:11 am

I dispute that one can calculate the VEI rating of an eruption at an “unknown location” from an ice core at a known location.

How do you get from there to a sweeping generalisation about “ALL of the other minimums “?

Burl Henry
Reply to  Greg
October 29, 2018 9:27 am


The sulfate levels in the Ice cores were typical of other known VEI6 eruptions, allowing the estimate to be made (reportedly 818 ppb, in this instance).

The ONLY cause of decreased temperatures is increased amounts of SO2 aerosols in the atmosphere, primarily of volcanic origin.

( As I have pointed out elsewhere, all proxy measurements of changes in solar activity are actually due to changing levels of volcanic SO2 in the atmosphere, which intercept much of the incoming cosmic radiation that forms the C and Be isotopes,and giving false impressions that solar activity has changed )

John Tillman
Reply to  Burl Henry
October 29, 2018 11:35 am


The effects of volcanic eruptions vary greatly depending upon their location, not just their magnitude measured in cubic volume of ejecta. The amount of S released also is important.

But not even the mightiest Holocene eruptions have affected climate for decades, as do solar minima.

Burl Henry
Reply to  John Tillman
October 29, 2018 3:13 pm

‘John Tillman:

“But not even the mightiest Holocene eruptions have affected climate for decades, as do solar minima”

1. No, but strings of large volcanic eruptions, as happened following the Roman Warming period, and during the Little Ice Age affected temperatures for decades.

2. The alleged “solar minima”cooling was actually due to volcanic eruption cooling, rather than any change in solar output.

John Tillman
Reply to  Burl Henry
October 29, 2018 3:55 pm


1) There weren’t really more large eruptions per century during the LIA or Dark Ages Cool Period than during the Roman, Medieval and Modern Warm Periods. The VEI relies on mass of ejecta rather than S molecules, so is only very roughly indicative of climatic effects, but here are the numbers of VEI 6 and 7 eruptions per AD century, based upon that index (earlier centuries perhaps not as well sampled; period dates approximate):

Roman WP (began BC)

1st: two 6
2nd: none discovered or recorded
3rd: one 6, one 7 (AD 230 +/-16)
4th: none discovered or recorded
5th: one 6

Dark Ages CP

6th: one 6 (540 +/- 100, so possibly in RWP)
7th: one 6
8th: two 6?
9th: none discovered or recorded

MWP (some would assign 901-950 to DACP)

10th: one 6 (930 +/- 200!), one 7 (969 +/1 20)
11th: none discovered or recorded
12th: none discovered or recorded
13th: one 6, one possible 7 (1257)
14th: none discovered or recorded


15th: one 6, one possible 7 (1452-53)
16th: two 6
17th: two 6
18th: two 6
1H 19th: one possible 6, one 7 (Tambora, 1815)

Modern WP

2H 19th: one 6 (Krakatoa, 1883)
20th: three 6

Now I guess you could look at VEI 4 and 5 eruptions to try to make a case for more S compounds in the air of cool periods, but those typically produce pretty small amounts, which rain out locally, rather than be injected high enough in the atmosphere to circle the globe. And I’m not sure that there actually were more, for example, in the LIA than MWP.

2) Variations in the solar cycle before telescopic observations can be reconstructed using 14C and 10Be isotopes, as shown by WEA and Leif’s work.

John Tillman
Reply to  Burl Henry
October 29, 2018 4:02 pm

PS: I assigned the VEI 6 eruption of Mount Churchill, Alaska to the 7th century, based upon its central date of AD 700, but it’s also ±/- 200 years. Similarly the possibly VEI 6 eruption of AD 800 +/50 on New Britain was assigned to the 8th century.

Tom Abbott
Reply to  tty
October 29, 2018 6:27 am

“at a time when climate history was still a science”

If we want to understand climate history we would be better off reading old newspaper reports than reading tree rings.

Thanks to all for the good commentary on this subject.

John Tillman
Reply to  tty
October 29, 2018 11:32 am


Besides instrumental and proxy data, we also have historical documents in order to reconstruct climate.

As you note, it has long been observed that low sunspot numbers coincide not only with cool intervals but with the Four Horsemen of the Solar Minima: famine, war, pestilence and societal collapse.

The Wolf Minimum has been assigned both to the Medieval Warm Period and the LIA. It should surprise no one that, starting from peak MWP warmth, it took a while for the cooling effect of this relatively minor solar minimum to kick in. The Spoerer was not only deeper and lasted longer, but hit in an already cooling world. That goes double for the even deeper and longer Maunder. The rapid recovery on the 18th century made the impact of the less dramatic Dalton even less severe.

The Wolf struck during the “worst century” (in Europe and many other places), the 14th, which began with the Great Famine, continued with start of the Hundred Years’ War, followed by the Black Death. In Europe, society didn’t collapse, but proto-Protestants challenged Catholic orthodoxy in England (Lollards) and Hungary (Hussites). Had climate not recovered in the second half of the 14th century, Christian Europe might have suffered collapse, comparable to that which struck during the Dark Ages Cool Period, following the Roman WP, or that of the Greek Dark Ages, after the Minoan WP.

Elsewhere in the world, civilizations did collapse, leading to folk migrations comparable to the barbarian invasions of Europe during the Dark Ages.

John Tillman
Reply to  John Tillman
October 29, 2018 11:42 am

PS: Christian Europe didn’t completely collapse during the Dark Ages, either, but it contracted. That many Germanic invaders were already Christian, albeit heretical, helped. Then came the pagan Norse and Muslim Arab and Berber raiders and invaders. Neverheless, Eastern and Western Christendom recovered and expanded during the High Middle Ages, while Zoroastrian Sassanian Persia succumbed totally to Islamic conquerors from the Arabian Desert.

John Tillman
Reply to  John Tillman
October 29, 2018 3:08 pm

Put another way, the initial effect of a solar minimum will be modulated by the background climatic state or conditions under which it starts. Among a variety of other modulating factors, in addition of course to its own duration and depth.

Bob boder
October 29, 2018 4:58 am


Shift the temperature record back 150 to 200 years eyeballing it looks interestingly close, not that I think it means anything.


October 29, 2018 5:27 am

However, the other minima do not line up with much of anything….

Looks like they line up perfectly to me….when you consider how inaccurate tree rings are the further you go back…and also spots
It’s not that the tree rings don’t show it…’s that it’s almost impossible to get the dates right

Dr Deanster
October 29, 2018 5:55 am

I see two wiggly lines, no trends in either, and no cause effects in either.

Willis …. thank you for proving there is no Global Warming at all over the last 800 years, errr … at least if there was any global warming, it bipassed Scotland.

October 29, 2018 5:58 am

Scotland sits in the upper latitudes surrounded by water and its climate on a macro scale is primarily determined by the North Atlantic (NA). Since the predominant wind direction is west, when the NA is warm, Scotland is warmer. When the NA is cold, Scotland is colder.

Aside from the water moderating its climate and since Scotland sits so close to the Arctic, if you get blocking in the winter, the polar jet can drop south of it and the temperatures can get brutal. A northeast flow off the Arctic over snow covered land in January at 55N is not Miami.

With the satellite era, we now can get a very good idea of where the large warm and cold pools reside across the world’s oceans. And we also are getting a pretty good idea of how these pools can influence where the persistent highs and lows form during the winter, which directly influences the polar jet patterns especially in winter. We also know the wavelengths of light from the Sun changes when it is active or not, which also influences heating of the oceans.

Since the oceans are so big, contain 99% of the stored heat and takes a lot more time to heat up a degree than the air above it, if you increase or decrease the heating of the oceans from the Sun, it’s going to take quite a bit of time before you see it. Then you have to move the heat out of the lower latitudes into the upper ones to change the winds to form the resultant highs and lows.

So if get into a period of decreasing solar cycles, the oceans are heated less during each cycle’s low point. Allowing for feedbacks to further moderate the process I would think it would take some time to see the cooling. Since pulses of warm water would still come out of the tropics, there would be times of milder winter weather if the polar jet flattens. It would be a downtrend but not a very smooth one.

So is it plausible that reduced solar activity resulted in the longer minimums? I think yes but you aren’t going to produce two graphs that overlap showing it. There is going to be a lag and the lines up or down are going to be ragged.

Wondering Aloud
October 29, 2018 6:38 am

Looks to me like tree rings are not a good way of determining past temperature. Why would we think they were?

October 29, 2018 6:50 am

The width of tree rings have more to do with the available water than temperature. Altitude, place, and sunlight. I don’t see how anyone can draw a conclusion about temperature from the width of tree rings. Did they compare the northern range of pine trees with the southern most range of the pine trees? Did they compare the highest level in altitude with the lowest? Hot and dry conditions will not expand the width of tree rings, while cooler and wetter will. That is not to say that trees will grow when the temperature goes below the temperature range for growth. But there is a range. And there are multiple ranges for trees to obtain growth. You can have years of temps during the growing season of near 100 F but little water, just enough to keep the tree alive. The width of the rings will be smaller. While the summers at 90 F or 80 F and wetter, the tree rings will be larger.

Ulric Lyons
October 29, 2018 6:50 am

The sunspot number reconstruction is very poor. There were centennial solar minima beginning from close to 1320, 1430, and 1550, which agrees with the tree ring proxy.

The three coldest periods in CET were all during solar minima.

comment image?w=747

Burl Henry
October 29, 2018 7:11 am


The discrepancy between Scottish tree ring data and reduced solar activity, which you point out, arises from the fact that it is IMPOSSIBLE to determine changes in solar activity through proxy measurements of C and Be isotopes, due to interception of incoming cosmic radiation by volcanic
Sulfur Dioxide aerosol emissions.

The proxy measurements actually detect varying levels of volcanic activity, rather than any changes in solar output.

Reply to  Burl Henry
October 29, 2018 7:20 am

You don’t know much about radiation physics do you? If you did you would realize that your theory is about equivalent to using a gossamer sheet to stop incoming bullets.

Dr Francis Manns
October 29, 2018 7:39 am

I would never imagine a one to one relationship between the cause and the effect of the sun and the earth because of the huge oceanic temperature buffer effect. What has happened may be cumulative over a few cycles. The cyclical decrease in the solar magnetic shield is now occurring from Cycle 22 to 24 to 2018, and we appear to be in a hiatus. It takes years because it has taken deep time to build climate stability with its minor aberrations from the mean.

The global T is suspect in any case because of the cultural effect. Toronto Pearson Airport is several degrees higher T than The Billy Bishop Airport. One has 100 TO/Landings /hr of Jumbo Jets and the other is 25 Turboprops a day.

October 29, 2018 7:54 am

The only real conclusion I can draw is that tree rings are a really bad proxy for sunspot numbers.

Bob Weber
October 29, 2018 7:55 am

Willis explained how he standardized the y axis. What about the x-axis?

Svalgaard’s reconstruction is in decadal data, one datum every ten years.

Decadal averages hide a lot of the action.

The Scottish Pine data is based on something different, no?

You’re counting on the SSN reconstruction being right. Remember what Leif said,

This convergence of the recent cosmogenic and solar activity records (see also Muscheler et al. 2016) lends credence to the admissibility of making a leap of faith back to the beginning of the WEA reconstruction nine millennia ago, Figure 4, even if we have to admit that it is not clear if the very long-period variations are of solar origin.

Your graphic shows fairly good correspondence since ~1620, near the time of real SSN data, possibly indicating flaws in the WEA reconstruction, not Leif’s use of it.

Gary Pearse
October 29, 2018 7:55 am

If all but the recent sunspot minima had faithfully coincided everywhere with significant temperature drops, then one could aver that the present warming was possibly due to greenhouse gas increases. I have to agree (assuming Leif’s dates match his data reasonably well) that the ssn minima and temp drops don’t match up consistently. This is one failed relationship that illustrates sceptics can be as tenacious as ghg warming proponents in hanging on to failed theory.

Bob Weber
Reply to  Gary Pearse
October 29, 2018 8:15 am

Some skeptics realize the limitations of thousands of years old tree and cosmogenic proxies.

I doubt the climate control issue can be resolved with this data.

October 29, 2018 7:57 am

Ridiculous to use trees. Use Ocean mud. The Oceans warm and/or cool based on the Sun. Trees are affected by Ocean temperatures, Arctic Ice, Water vapor, Rain, etc…….

October 29, 2018 8:54 am

Largest look at the longest data? I remember a short look at data as long as the Nile, and as lucid as aurorae.

Per Feynman, Joan, et al.

Bob Weber
October 29, 2018 9:18 am

Finally, in recent times, you can see that sunspots started decreasing about 1980, while temperatures have risen during that time.

An old canard. This is what drew me back in the day, why is this?

PMOD depicts a non-linear SSN-TSI relationship that becomes more linear with increasing solar mean field strength:

comment image?dl=0

The rankings show a “sweet spot” for TSI when SSN is 160-220; note the highest TSI years are not during the highest SSN years:

Rank PMOD1709 SSN
2002 1361.6119 163.6
2000 1361.5917 173.9
2001 1361.5312 170.4
1980 1361.5147 218.9
1981 1361.5048 198.9
1989 1361.4849 211.1
1979 1361.4294 220.1
1990 1361.4294 191.8
1999 1361.3642 136.3
1991 1361.3542 203.3

The SC23 ’99-02 TSI climb provided the energy for the step-up after the ’98 ENSO.

Finally, the modern temperature rise is owed to sunspot activity being higher than the amount necessary to just maintain the temperature, the decadal warming/cooling v2 sunspot number threshold of 94, for much of the 1978-2003 period, and in again in 2013/14.

Matt G
Reply to  Bob Weber
October 29, 2018 10:00 am

Although this could be a resolution issue regarding the sunspot reconstruction. The recent solar cycles have less variability compared with earlier times of the last millennium, so this will effect climate differently.

Reply to  Bob Weber
October 29, 2018 1:59 pm

Correct Bob, but minds on this subject have been made up and no one is going to change their mind.

October 29, 2018 9:22 am

That is because there is only one driver of the climate. Climate is not, absolutely and totally not driven by thousands of different processes which have their own timing, connections, lags and other variables. Thus, we can determine that sunspots have no effect at all on climate.

Burl Henry
October 29, 2018 9:36 am


Far from a gossamer sheet, SO2 aerosols (tiny droplets of Sulfuric Acid) are millions of times larger than C and Be atoms.

Reply to  Burl Henry
October 30, 2018 2:49 pm

Which matters not in the least. 14C and 10B are created by nuclear reactions. By interaction of high energy neutrons with 14N nuclei and spallation of 14N and 16O nuclei respectively. The oxygen atoms in SO2 will work as well as any other oxygen nuclei, so the only difference those SO2 droplets will make is in the very rare cases when a cosmic ray particle hits a 32S nucleus. Which will happen very, very rarely since the proportion of sulfur atoms to oxygen and nitrogen atoms in the atmosphere is infinitesimally small even after the largest volcanic eruptions.

That those aerosols have a climatic effect is because they can both absorb and scatter sunlight which is low energy and will interact with the whole droplet which isn’t millions, but billions of times bigger than the nuclei.

Matt G
October 29, 2018 9:45 am

Some comments have already included some problems with these reconstructions, but there is also another factor although impossible to found out at the moment during the past.

The mode of different wavelengths from the sun changes through time so temperatures will affect oceans differently depending how far these penetrate them. The sun may show different activity of sunspot periods, but these are only comparable with exactly the same shortwave radiation from different bands of the emission spectrum.

1) Increase the length of overall wavelengths reaching the planet and the oceans will cool because more of them will only come in contact with shallower depths.
2) Decrease the length of overall wavelengths reaching the planet and the oceans will warm because more of them will come in contact with deeper depths.

Until this is known more secrets of solar activity on climate will be hidden.

Reply to  Matt G
October 30, 2018 2:53 pm

Variation in the visible wavelength is very small. The variation in UV is considerably larger, but most of this doesn’t reach the surface but rather is absorbed in the stratosphere. So it is in the stratosphere, not in the sea where one would expect solar variability to have a major effect.

Doug Sorensen
October 29, 2018 10:17 am

To be a little more precise, this data indicates that some variation in the Sun’s activity may or may not have caused temperature variations, but sunspot data is not an indicator of it.

Bob Weber
Reply to  Doug Sorensen
October 29, 2018 11:02 am

That’s not very precise. It’s more precise to say the WEA reconstruction may not result exclusively from sunspot activity, making it a suspect solar proxy and temperature indicator, meanwhile the observed sunspot data since the 1600’s is a better solar energy proxy and indicator of temperature variations.

Reply to  Willis Eschenbach
October 29, 2018 11:38 am

So pine trees that show growth from may to August are a suitable proxy for a four seasons instrumental temperature?

Fine by me, as it illustrates the extraordinary rise in temperature from 1690 unprecedented in the modern era.

Now, do you want to tell dr Mann he was right after all ? A nice phone call or an email?


John Tillman
Reply to  Tonyb
October 29, 2018 11:45 am


IMO tree rings can be used as proxy data, although more for net precipitation than temperature. The main problems with Mann’s misuse of them are his fractured fairly tale statistical analyses and tacking an instrumental record onto these cherry-picked, upside down, bent, folded, spindled, mutilated and abused curves, with hanging chads.

Reply to  John Tillman
October 29, 2018 12:03 pm


Yes, I am happy with some proxy for precipitation . Bearing in mind the limited growing season and the nature of the micro climate in a forest , apart from any quasi scientific related matters, I do not see the proxy for being valid.

I think I remember people coming up with all sorts of tree ring proxirs sch as sales of burgers correlated closely.

I am sure Willis will have more to say


John Tillman
Reply to  Tonyb
October 29, 2018 12:19 pm


Since temperature and precipitation are related, it is possible, IMO, with careful scientific technique, to derive a T signal from tree rings, at least in some cases.

Such as the papers here, from last year:

Tree rings and climate in Scandinavia and Southern Patagonia

But Mann, et al, engaged in scientific malpractice and statistical sleight of hand in order to fabricate their HS, or intentionally sloppy, at best.

John Tillman
Reply to  Tonyb
October 29, 2018 12:32 pm

Another recent example of teasing out T from tree rings, by comparison with sez ice and SST:

A 70–80 year periodicity identified from tree ring temperatures in Northern Scandinavia and its relation to the Arctic sea-ice oscillation AD 550–1980

IMO, simply eyeballing solar cycles show that at times multi-cycle periodicities occur, with waxing or waning magnitude in following cycles, although rarely six or seven such ~11-year fluctuations in sequence.

This is the former cycle reconstruction, but close enough for intergovernmental work. It shows, with one exception, rising magnitude during the 18th century recovery from the Maunder, followed by the Dalton Minimum.

The Modern WP also shows up from the mid-19th century, with a drop off in general from the late 20th century. IMO, the overall decline since then wasn’t enough promptly to overcome the accumulated heat of the prior century or so.

Some scientists argue that Earth soon radiates away increased solar radiation absorbed during higher activity intervals, but others are convinced that heat does accumulate over time, to be moved around by oceanic and atmospheric currents and oscillations before being lost to space. So that lags exist and can be observed, akin to the effect of added GHGs in raising emission height in the troposphere.

John Tillman
Reply to  Willis Eschenbach
October 29, 2018 12:14 pm


We agree that Mann is a charlatan and trickster, who doesn’t practice the scientific method, but instead advocacy, with all the ruses of persuasion and none of the valid data and reasoning therefrom that ought to characterize science.

But it has worked for him, to include funding from Big Oil.

Reply to  Willis Eschenbach
October 29, 2018 12:52 pm


“What are you calling the “modern era”? 1690 onwards? Because if you mean say from 1200 onwards, the modern rise is far from either the fastest or the largest.”

No, I meant the modern era from 1690 for which we have instrumental temperature records.

I had been selling tickets for seats to eavesdrop on your phone conversation with Dr Mann. Guess I will have to think of another way to earn an honest penny.

In all seriousness, the proxy is interesting but of course it SHOUDNT be correct, as a four season temperature is somewhat different to a may to august imperfect tree record.

However the peak around the 1500’s then the drop afterwards matches my published reconstruction of CET to 1538 and the rise in the 1300’s after the cold of the 1200’s again matches the reconstruction I am currently working on. Curious.

John Tillman
Reply to  tonyb
October 29, 2018 1:10 pm


It’s the rise in the second half of the 14th century which makes dating the start of the LIA problematical. I prefer beginning around AD 1400, but others, to include Mann, back when he believed in the MWP, ended it c. 1250. That’s too early, IMO, even if one assigns the Wolf Minimum to the beginning of the LIA rather than last cool cycle toward the end of the MWP.

So the MWP either suffered only one minor minimum, the Oort, or two, with the middling Wolf Minimum as well. And hence the LIA owed either to three or four minima, the three being the bigger Spoerer, biggest Maunder and lesser Dalton.

The Modern WP has yet to experience any distinct minimum at all. Some think we might be in store for a Dalton-level hit, but those predicting an impending Maunder-like event are, IMO, liable to be shown incorrect.

Reply to  tonyb
October 29, 2018 1:51 pm


Mann believed it was a major volcano eruption in 1250 that precipitated the LIA or ended the mwp , depending on how you want to look at it.

I have acquired hundreds of observational recrds from the period and 1250 was merely one of a number of cold years in that period, all interspersed with warm years. I seem to remember that miller and his moss also claimed a down turn but its not apparent when you look at the extended record in context

I haven’t done a study yet of the 1400’s so can not comment on the climate in that period


John Tillman
Reply to  tonyb
October 29, 2018 2:02 pm


Yes. Some have blamed the volcanic eruption of AD 1257 for the end of the MWP. Before 2009, Mann might have been among them.

But in Mann, et al., 2009, he blamed shifts in Atlantic wind patterns from radiative forces for the only regional MWP and LIA:

Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly

There were, as you note, good and bad years in the second half of the 13th century.

Reply to  tonyb
October 29, 2018 2:15 pm


You will note that I started this thread by referring to my article that I entitled ‘the intermittent little ice age’

I think this notion of a climatic deep freeze lasting from say 1200 to well into the 1800’s is a simplistic one. There were plentyof periods of cold weather in the warm spells and plenty of warm weather in the cold spells.

The intense periods of cold appeared to be concentrated and intermittent but having said that a twenty year period of mostly cold winters and cool summers would wreak havoc with an agrarian based society

What effects the intense cold spells had on sea temperatures and wind direction, jet stream etc and therfore on subsequent weather is something that people like Lamb used to investigate but no one is dong that sort of work these days.

John Tillman
Reply to  tonyb
October 29, 2018 8:22 pm


My concept of centennial scale warm and cold secular trends starts with Bond Cycles, which are the interglacial equivalent of D/O cycles in the longer glacial cycles.

Within each secular trend, whether warming or cooling, lie stronger or weaker counter-trend cycles, ie multidecadal warmings within cool periods, such as the early 18th century warming coming out of the Maunder Minimum, or coolings during warm intervals, such as the c. 1945-77 dramatic cooling during the Modern WP.

But they’re all down more or less to the sun, IMO, as modulated by previous and prevailing conditions on Earth.

Samuel C Cogar
October 29, 2018 11:06 am

The author states that, to wit:

Now, the commenter was indeed correct that the low temperature in 1690 was during the Maunder Minimum.

However, the other minima do not line up with much of anything.

When I look at the above noted Scottish Tree Ring-Svalgaard Sunspot graph …. I simply discredit the “tree ring” temperature proxy data because there are far too many variables that can affect the seasonal growth of a tree’s cambium layer which is responsible for adding a new layer of xylem (tree ring) to the tree’s trunk and branches (limbs).

And in the case of “Scottish Pine Temperature Reconstructions” via use of the “growth rings” or ”tree rings”, …. it would not be illogical, unreasonable or unprofessional to infer, suggest or claim that the aforesaid Scottish Pine growth rings are highly unlikely to be affected by any near-surface temperature increases/decreases associated with Sunspot activity, ……. simply because, to wit:

The climate of Scotland is temperate and oceanic, and tends to be very changeable. As it is warmed by the Gulf Stream from the Atlantic, it has much milder winters [6 °C – 43 °F] (but cooler, wetter summers [18 °C – 64 °F]) than areas on similar latitudes ” Source:

Therefore, …. maybe, ….. just maybe, …… the aforenoted Scottish Pine Temperature Reconstruction proxy …… can also be cited as being a Gulf Stream Temperature Reconstruction proxy. 😊 😊

Richard Ding Dong Bell
October 29, 2018 11:07 am

Try using Haggis rings ….. way more tasty !!!!! thee noo.

October 29, 2018 11:15 am

In general, it appears to me that tree rings make good proxies only for temperatures that you are looking for.

Tree rings are subject to so many other variables that they may only give general hints to provoke better methods.

Bob Weber
October 29, 2018 3:58 pm

Using 10yr vs 1yr SSN averages distorts the accumulation curve:

comment image

This means decadal reconstructions won’t work very well for climate work.

John Tillman
Reply to  Bob Weber
October 29, 2018 4:06 pm

Good point.

But IIRC, and I might not, so I hope that Leif will correct me if wrong, he doesn’t buy the heat accumulation hypothesis, since IHO, Earth rapidly radiates any extra heat away to space.

I incline toward your view, in which our water world is capable of storing heat accumulated over more powerful solar cycles for some time, producing a lag effect in cooling when weaker solar cycles occur.

John Tillman
Reply to  John Tillman
October 29, 2018 4:09 pm

And moving that accumulated heat around via oceanic and atmospheric circulations and oscillations.

There are of course also negative feedback effects, such as increased evaporative cooling and possibly cloudiness as a result of more solar radiation hitting the tropical oceans for longer intervals. Ours is a largely homeostatic planet, as long as other conditions remain basically the same, such as tectonic arrangements and Milankovitch cycles. But we can tip from interglacial to glacial phases and out of them at geologically prompt rates.

John Tillman
Reply to  John Tillman
October 29, 2018 4:13 pm

Some studies have found that oscillations such as ENSO occur more often and with stronger magnitude during warmer, sunnier intervals.

It was once thought that during the balmy Pliocene, without the Isthmus of Panama, Los Ninos were more or less constant, so that ENSO was less an oscillation than a nearly permanent phenomenon. This proposition might not be as widely held now as formerly.

Bob Weber
Reply to  Bob Weber
October 29, 2018 4:41 pm

Thanks John. Our thinking is similar.
My graphic should say “Sum of SSN-94″.

John Tillman
Reply to  Bob Weber
October 29, 2018 4:48 pm

De nada.

For the Sum of the Sun, you graduate Summa.

Burl Henry
October 29, 2018 6:07 pm

John Tillman

Re your post of Oct 29, 3:55 pm:

For my reference, I have used “Volcanoes of the World”, 3rd edition (2010).

(1) The Roman Warming Period ended with the VEI6+ eruption of llopango (El Salvador) (450 AD), and the Plinian (most powerful category known) eruption of Pele (c. 450 AD). This was followed by Vesuvius (VEI5), in 472, and at least 71 VEI4, or higher eruptions in the interval before the MWP, including 3 additional Plinian eruptions in c. 730, 823, and 890.

With respect to the LIA, references typically assign its beginning to the eruption of Mount Rinjani (VEI7) in 1257, followed by the eruption of Quilotoa (VEI6)(c. 1280) and a string of 25 VEI5, 5 VEI6 and 1 VEI7 (Tambora)(1815). between then and its “end” in 1850 . There were also at least 95 VEI4 eruptions within the period, which would have contributed to maintaining the cooling.

(Within the period 1850-present, there have been 31 VEI4 eruptions that have spewed enough SO2 into the atmosphere to cause the formation of a La Nina, so their cooling effect is far from negligible)

(2) “Variations in the solar cycle before telescopic observations can be reconstructed using 14C and 10Be isotopes”

NO, they cannot. Observed reductions in isotopic levels are are due to interfering levels of volcanic SO2 aerosols in the atmosphere, and not due to changes in solar output. This CAN be proven

John Tillman
Reply to  Burl Henry
October 29, 2018 6:19 pm


I’d be obliged if you could prove that 14C and 10Be isotope levels can be shown to correlate with SO2 levels in the air rather than solar output. I have not seen any studies to that effect. Thanks!

The beginning of the LIA is not typically assigned to AD 1257. Only CO2 special pleaders date the end of the MWP from that time.

I’d also appreciate it if you could show all the VEI 4 and 5 eruptions which you suppose caused the LIA, and compare and contrast their frequency during that interval with before, during the MWP, and after, during the Modern WP.

Then kindly please explain why prior such warm and cool fluctuations in the Holocene lack volcanic connections, and the same for all previous interglacials of the past 2.6 million yeas.

Thanks again!

Burl Henry
Reply to  John Tillman
October 29, 2018 9:10 pm

John Tillman:

I had posted this on a previous thread, but here it is again:

“I would point out that it is IMPOSSIBLE to determine changes in solar activity via proxy measurements , because of varying interference from volcanic SO2 aerosols (tiny droplets of H2SO4) in the atmosphere.

This can be proven by examination of the graph “Solar Irradiance, 1880-present”, which was constructed from proxy measurements, as those of the LIA, and other eras. It can be Googled.

It shows, for example, a solar minimum between 1983-1986, which coincides with the 1984-1985 La Nina (caused by increased SO2 levels from the El Chicon eruptions of 3-29-82 (VEI4+) and 4-3-82 (VEI5).

It also shows a large solar maximum (again, for example), between 1985 and 1995, which coincides with the El Ninos of 1986-88, 1991-92, and 1994-95, all of which were due to reductions in the amount of atmospheric SO2 aerosol levels.

Thus, these changes, attributed to changes in solar output, were instead caused by changes in atmospheric SO2 aerosol levels, which changed the magnitude of the proxy measurements, and led to erroneous conclusions.

Finally, satellite TSI measurements are available for the above periods, and they show NO corresponding large changes in solar output”.

Regarding prior Warm and Cold periods throughout Earth’s history, there is no reason to believe that they were not also driven by volcanic activity. Ice Ages could easily be maintained by extensive volcanic activity, and the cessation of extensive volcanism would explain the rapid warming seen at the end of Ice Ages, with their volcanic SO2 aerosols settling out of the atmosphere within a decade, or less.

Further responses to your questions will require another post.

Reply to  Burl Henry
October 30, 2018 3:02 pm

See my comment above. SO4 droplets will have virtually no effect whatsoever on 14C and 10B production since the proportion of sulfur nuclei to nitrogen and oxygen nuclei will be extremely small even after the biggest eruptions.

Burl Henry
Reply to  tty
October 30, 2018 5:02 pm


You need to re-read my comments.

I pointed out that when SO2 levels increased , proxy measurements of the 10Be and 14C decreased. And when SO2 levels decreased, proxy measurements of 10Be and 14C increased. And that satellite measurements showed NO corresponding changes in solar irradiance.

All of this indicates that my analysis is correct, and that your objections are meaningless. However, I am open to an alternate explanation of the facts, if you can provide one.

Reply to  tty
October 31, 2018 8:03 am

“All of this indicates that my analysis is correct, and that your objections are meaningless”

Since your theory requires extensive revision of basic nuclear physics I think you will have to do better than just wiggle matching. How significant is the correlation? Five sigmas or better?

John Tillman
Reply to  Burl Henry
October 30, 2018 3:08 pm


Glaciations lasting tens of thousands of years or more can’t be maintained by volcanic eruptions. For one thing, volcanism can warm the atmosphere as well as cool it.

The Cretaceous Period was much more volcanic than most of the Cenozoic Era, eyt it was hot, hot, hot, not icy. By contrast, the cold Carboniferous and early Permian Periods were comparatively non-volcanic.

Burl Henry
Reply to  John Tillman
October 30, 2018 6:15 pm

John :

“Glaciations lasting tens of thousands of years or more can’t be maintained by volcanic eruptions”

And the reason for that is ?

During the Little Ice Age, we were only a few large eruptions away from slipping into a new Ice Age. Once snow coverage and sea ice formation increase sufficiently, Earth’s albedo will change, and eruptions will have even greater effect in an already cooled climate.

As such, periods of extensive eruptions could easily have maintained Earth’s Ice Ages.

You may be correct about the extent of volcanism in the mentioned periods, although I find it difficult believe that much could be known about their occurrences in such distant times.

You correctly mention that volcanoes can also cause warming. However, the mechanism for the warming is cleansing of the lower atmosphere by the rain of stratospheric SO2 aerosols settling out, and flushing out others in the troposphere, on their way to the Earth’s surface, thus cleansing the air enough to increase insolation. But if there are frequent eruptions, any such warming would be quickly quenched, or might not even occur.

Wex Pyke
October 29, 2018 8:05 pm

I just think Eisenbach makes too much of too little data. Even Mann agrees with solar forcing of temperature.

Mann and friends : Solar Forcing of Regional Climate Change During the Maunder Minimum (

A better paper on climate forcing: Chapter 14 – Cause of Global Climate Changes: Correlation of Global Temperature, Sunspots, Solar Irradiance, Cosmic Rays, and Radiocarbon and Berylium Production Rates (

Wex Pyke
Reply to  Willis Eschenbach
October 30, 2018 4:19 am


Objecting to the premise, the idea that you are using one proxy to attack a single paper, and then taking that stawman to attack a huge swath of papers that show solar forcing is real, is not very scientific.

You can only handle one graph? I find this odd, you are arguing that a paper that attempts to look at all the data is wrong … because it uses too much data and thought? … but OK lets go to some easy math. Lets look at the single comparison of the best sunspot data graphed with the best temp data we have (which is manipulated). Graph NASA or any other temp data since 1978 against the sunspot data from the same period. What does it show? A correlation so clear that you don’t even need to run stats… does this under their “sun” section. Try it, you might like it.

As for Mann – you again create a strawman about what you think of him instead of thinking through that even folks on the other side (for whom the solar forcing is not just inconvenient but could threaten their whole lie) agree that it exists.

Goodbye and good luck!

Reply to  Willis Eschenbach
October 31, 2018 10:08 pm

“Point me to an unpaywalled version and I’ll be happy to take a look.”
It’s here.

October 30, 2018 3:39 am

“Then we have the Maunder Minimum. Temperatures started dropping about 150 years before the start of the Maunder Minimum, and during the first hundred years of dropping temperatures the sunspots were increasing.”

The drop does coincide with first European contact with the New World and resultant decimation of native American populations. This would have caused a reduction in agricultural activity and forest regrowth.

The drop beginning late 14th century also coincides with the peak of the Plague in Europe.

Reply to  Willis Eschenbach
October 30, 2018 3:20 pm

I think you are wrong there Willis. The amount of agriculture practiced before European contact was quite extensive in the southeastern US and very extensive in Central and South America. Large parts of the Amazon were farmland in 1500.

The earliest spanish explorers like DeSoto in the southeastern US and Orellana in the Amazon describes densely populated country with large towns and kingdoms.

John Tillman
Reply to  tty
October 30, 2018 3:37 pm


Agriculture, or at least cultivation, was also practiced in the NE US and SE Canada, well into the Midwest. Remember Squanto’s fish fertilizer and Pocahontas’ tobacco.

The Spoerer Minimum led to the collapse of civilization in the Mississippian Culture:

And to agriculture in much of the US SW:

The main regions of North America which didn’t support much agriculture in AD 1492 but do now were the Great Plains, the Pacific Coast and intermountain NW. Nature was so bountiful on the CA and PNW coasts that, while the people knew about agriculture, it required more work without much more reward than hunting and gathering.

John Tillman
Reply to  John Tillman
October 30, 2018 3:39 pm

Indians did however burn grassland and forest to manage their resources.

And there was ag on the Great Plains along the major rivers, as in the Mandan villages on the Missouri.

Reply to  John Tillman
October 31, 2018 8:10 am

Yes, however some of the Northwest Coast indians did grow tobacco, they really wanted that and couldn’t get it by hunting and gathering.

The Jomon culture in Japan was somewhat similar. It lasted for more than 10,000 years as a sedentary hunting/gathering culture without ever adopting farming. Also in a rich coastal environment.

Reply to  Willis Eschenbach
October 30, 2018 7:03 pm

An often quoted number is that 95% of native americans were wiped out by diseases introduced by europeans. This included the Aztecs and Incas as well as N Americans. There is also some thought that the bison underwent a huge expansion following this.

Reply to  Phil.
October 31, 2018 8:13 am

It has been speculated that the vast numbers of Passenger Pigeons was also a temporary and abnormal phenomenon due to the expansion of young productive oak forests on abandoned farmland (the pigeons largely lived on acorns).

Reply to  Willis Eschenbach
October 31, 2018 7:15 am

As others have pointed, it is certainly more than just the US involved. Population densities, and presumably amount of agriculture, in Mexico and Central America were much higher.

The Amazon is a real unknown. I don’t doubt the large populations but I’m not sure how much land clearing was involved vs. more intensive agriculture on a smaller amount of land.

Interestingly, the Cahokia link mentions a 14th century decline possibly related to deforestation. Agriculture without plows and modern seed would be more land extensive and necessarily involve more land clearing to sustain a population than today’s agriculture. Even with the decline of the large centers (the sort of things most easily studied), the people don’t go anywhere but just keep doing what they were doing in a more dispersed manner. Or, the centers move elsewhere.

We need to look not just at the effects on the carbon budget of deforestation and reforestation but also the effects on clouds from aerosol production.

I’m not arguing for a single explanation. I think the great fault of many is to look for some simple explanation – like the sun or planetary cycles or whatever – when we are dealing with a very complex system and a lot of moving parts.

Reply to  James Cross
October 31, 2018 8:18 am

And of course we also have the collapse of the Anasazi and Hohokam farming systems in the SW, though at least the Anasazi collapse was earlier and very likely connected to 13th Century megadroughts.

Reply to  tty
October 31, 2018 8:37 am

The collapse of the Classic Mayan Civilization (approx. 900 AD) is sometimes also attributed in part to drought. Some think there is an association between deforestation and drought. And, even if periodic droughts have other explanations, deforestation could exacerbate them.

October 30, 2018 8:15 pm


This is not personal, your tone sure does not seem to show a common interaction with the normal scientific discourse. How many of your solar publications were peer reviewed?

As for Mann, here it is unpaywalled from Mann’s own website, thoughts?

The paper I cited is complex but it is certainly not tripe.

As for your graph, a linear comparison over the timeframe is irrelevant, isnt it? The timeframe covers several solar cycles where temperature would be predicted (by “solar forcers”) to wax and wane with every solar cycle thus a linear regression would need to go from peak, or just after peak, to each sunspot minimum. Look at your own graph, it shows temp dropping, or at least increasing at a lower rate, during sunspot lulls each eleven years. You find this in every temp record since ’78.


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