Svensmark's Cosmic Theory and Cloud Cover Depictions in Little Ice Age Art.

Guest essay by Dr. Tim Ball

Correlation between sunspot numbers and global temperature was known for decades, but with no proven mechanism it was correctly set aside. That changed when Henrik Svensmark proposed his Cosmic Rays hypothesis. Figures 1 and 2 show the mechanism in two different ways. Figure 2 is from The Chilling Stars by Svensmark and Calder, the book that took the idea to the public.

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Figure 1                                                          Figure 2

The Cosmic effect is now established through rigorous attempts to disprove it, the proper scientific method.

IPCC Challenge

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Figure 3. IPCC Figure 7c

A major objective of the 2001 IPCC Third Assessment Report (TAR) was to counter the evidence in Figure 7c from the 1990 First Assessment Report (FAR) (Figure 3). It was troubling because it showed significant variations of temperature over the last 1000 years. This appeared to contradict the IPCC claim that 20th century warming was unique and abnormal. The major focus was the depiction of the Medieval Warm Period (MWP) from approximately 950 to 1350 AD, but the cold spell from 1350 to 1850 known as the Little Ice Age (LIA) was also a concern. As Lamb noted (personal communication) the onset and termination of these periods varied regionally, sometimes by decades.

Artists Images Of The LIA

We all see the world through different eyes with different sensibilities and awareness. In the classic nature-nuture division most of this is nature, especially with certain abilities, such as mathematics, music or art. Artists see colour, light, and patterns of the world differently. There is a basic for landscape artists because they paint what they see before them, albeit with artistic license on occasion. Their work provides evidence of conditions such as the snow and cold of the Little Ice Age by Breughel (Figure 4) or Grifier (Figure 5). There was an exhibition of the work of Hendrick Avercamp titled the Little Ice Age at the National Gallery in Washington from March to July 2010.

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Figure 4: Pieter Breughel the Elder, Hunters in the Snow

These artists considered the conditions relatively normal, especially if their lifespans were within the LIA. However, as landscape artists they would detect changing atmospheric conditions before others and be influenced by this in their work.

 

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Figure 5: Jan Grifier, The Great Frost 1683 (River Thames)

Changing Skies Are Evidence of Changing Climate

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Figure 6: John Constable, English Artist

Montana is known as “Big Sky Country” so the dominant feature in images are sky and clouds. This is true of any flat region, such as Saskatchewan, or Norfolk in eastern England. Artists naturally paint these skyscapes, but few with greater awareness than John Constable (Figure 6). He became so aware of the clouds that in 1821 he produced an entire book simply depicting clouds and cloud forms (Figure 8). There are several books analyzing these depictions. One of them, John Constables Skies, is subtitled A Fusion of Art and Science and poses the question, And were the skies he painted scientifically accurate? Published in 1999 it preceded the confirmation of Svensmark’s work on sunspots and cloud cover.

Constable’s works do not, in themselves, provide support for Svensmark, but when put with a 1970 study by Neuberger (republished in Weather on 30 April 2012) it provides independent confirmation. The beauty of Neuberger’s work, Climate in Art, is that it precedes by 29 years the beginning of the sunspot temperature connection outlined in Friis-Christensen and Knud Lassen’s Science 1991 article Length of the Solar Cycle: An Indicator of Solar Activity Closely Associated with Climate.

Neuberger’s hypothesis was that,

…a statistically adequate sample of paintings executed by many painters living during a given period in a given region should reveal meteorological features significantly different from those of a similar sample of paintings produced during the same epoch in a climatically different region.

He studied over 12,000 paintings in 41 European and American art museums. The period of coverage was from 1400 to 1967. Various definitions were assigned to standardize the categories including the US airways code of four categories,

clear (less than 10% of the visible sky covered by clouds)”,

scattered (10 to 50% clouds)”

broken (60 to 90% clouds)”

overcast (more than 90% clouds)

He divided the 1400 to 1967 span into three epochs as shown in Figure 7 (Figure 12 in the original article).

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Figure 7: Neuberger’s caption, Epochal changes of various painting features”

He labeled the epochs,

1400 – 1549 the pre-culmination period of the Little Ice Age

1550 – 1849, the culmination period which contains the years without a summer

1850 – 1967, the post-culmination period in which a definite retreat of glaciers and substantial atmospheric warming occurred.

When he broke this down by 50 – year epochs the percentages for average cloudiness were dramatic ranging from 29% for 1400 – 1449 to 77% for 1550 – 1599. As he noted,

The frequency of low and convective clouds also shows a sharp change from the first to the second epoch reflecting the deterioration of the weather throughout Europe.

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Figure 8: From a cloud study by Constable (1821).

J.M.W. Turner, a contemporary of Constable’s, also painted landscapes with extensive displays of clouds. He was more intrigued by the changing light conditions particularly after the eruption of Mount Tambora in 1815. Because of this his works are considered early English impressionism.

Conclusion

A critical part of climate reconstruction is to obtain corroborating information from different independent sources. This early empirical study by Neuberger supports Svensmark’s hypothesis that changing solar activity creates changing lower cloud cover, which causes changing temperatures.

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Mark Bofill

wince It seems like only yesterday I ate crow over supporting Svensmark’s cosmic ray theory without checking my facts.
I’ll go read the paper.
I’ll be back.

Has anybody ever seen a bristlecone artist?

YEP

Something (perhaps a lot) must have been dropped and is missing from this mysterious sentence fragment: “That changed when Henrik different ways.”

Mark Bofill

paywalled, but article here.

Oldseadog

“Cosmic effect is now established through vigorous attempts to disprove it, the proper scientific method.”
Please, someone tell IPCC, Dr. Mann, Al Gore, etc. etc. etc.

Oldseadog

Rigorous, not vigorous.
Stupid computer can’t spell.

It is good to see some (the last author and Svensmark) thinking outside the box. CO2 has been beat to death with nothing coming of it (there is as much indecision as decision).
I agree the answer will lay outside GHG gasses. They do play a small role, but not one that drives the major changes.

So. Now what about Gleissberg and de Vries Suess? 87 and 208 years. There are more. The cooling in these cycles naturally causes more clouds at the lower lat’s and that causes more cooling…. No need for Henriks theory.

rgbatduke

Correlation not being causality, it is better stated that there is a correlation between cloudiness and reported average temperatures. However, it isn’t necessarily the case that the Svensmark hypothesis is the causal basis. I could just as easily state that the cause is purely orbital, or due to variations in solar state other than solar magnetic, or due to variations in aerosol levels and consequent all-source albedo (both direct and from the aerosol/cloud secondary connection) from sources other than cosmic rays.
Is it colder because it is cloudier, or cloudier because it is colder? The pictures do not and cannot reveal that. All they can do is show that cloudier and colder tend to go together, which is surely no surprise, even as it doesn’t in and of itself prove or disprove any particular mechanism (where there might well be more than one!) producing the correlation.
Just before anybody gets carried away with the notion that this is “proof” of the Svensmark hypothesis…
rgb

Mark Bofill

Interesting.
from the article,

When the researchers examined cloud data collected by weather satellites over the past 22 years and compared them with 26 Forbush decreases, they discovered that, for the five strongest events, the water-droplet content of Earth’s clouds decreased by an average of 7%.

I wonder when those were, and if there were significant corresponding temperature anomaly fluctuations around those events? Strange if so that no-one noticed, although perhaps this is well known and I’m simply unaware of it.

Mark Bofill

Dr. Brown,

Is it colder because it is cloudier, or cloudier because it is colder?

That reminds me of Dr. Spencer’s arguments about the difficulties on disentangling forcings and feedbacks.

Mark Bofill

wait, this is from 2009?

zootcadillac

I welcome any work into the theory of cosmic rays and the possibility of cloud seeding. Somebody has to do it if only to remove it from the equations. That’s how science gets done. It’s better than the usual suspects spouting something about the red herring, TSI and dismissing all theories related to cosmic rays out of hand.
This story might be a step too far though. Here’s my cosmic ray picture 🙂
http://imgur.com/0RXd0ku

The problem as any theory of style will tell you is that art is not only influenced by nature,
but more importantly art is influenced by other art.
That is, art not only can imitate nature it can imitate other art. This is known as artistic influence.
Until you can quantify the extent to which art imitates other art rather than its subject, you don’t have anything.
On the science there is no connection between GCRs and clouds. Looking at the highest resolution data we have at 12 different pressure levels, I find nothing. zip. nada. zero.

zootcadillac

Sorr, I also meant to add that there is nothing atypical about the skys in those old paintings. Sure we don’t have the Thames ice fayres any more and it’s been a long time since we’ve seen a big river freeze but the huge cloudy skies are jut sunny old England going about business as usual. it’s been one of those days in the North today.

Mark Bofill

wait, this is from 2009?

Right, because I missed the point of the article. LIA art.
So we’re talking about art as temperature proxies?
Ok, but I’m not sure I like art proxies any better than any of the other proxies. I’ll think about it.
I’m going back to sleep now. Not that it appears I fully woke up in the first place. 🙂

Jon

Sorry, I’m not convinced. Artists are out to make a buck like everyone else, When one local artist has got rich by painting cumulonimbus clouds, others will follow suit. When the public gets sick of cumulonimbus they’ll paint cirrus, or clear skies, or whatever sells. Paintings aren’t done on the spot, immediately, like photographs. The main details are sketched in and the less important stuff — like clouds — is usually added later in the studio.
This is like saying that two-dimensional people were commonly found in Egyptian times and during the Cubist period.

emsnews

The false idea that the sun’s energy output is totally the same forever is WRONG. Dead wrong.
The sun has various levels of activity. This, in turn, causes the rotating planets that surround the sun to change their own temperature over time due to higher or lower energy output levels.
The ‘atom bomb’ sun becomes a ‘fire cracker’ sun as it destabilizes over time, that is, it is very, very old. Want to have a real scare?
The sun isn’t forever! Nor is our planet. Or even the universe itself.

kenw

Caution is warranted as artists are quite free to add/subract/modify clouds to impact the overall art piece. Artistically speaking, clear blue skies are pretty boring as are totally overcast. An artist is very likely to have ‘dressed up’ the sky if these conditions were at hand in reality or to add/subtract mood. My dad did it all the time in his watercolors. I’ve even done it with my photographs (heresy, I know…deal with it).
However, to me there is value in the overall representation since an observed consistency across several artists in a particular time/place would tend to discount individual ‘artistic license’. That appears the case here.
good stuff.

Rhoda R

I don’t see where the skies are any worse proxy than tree rings – ie neither particularly good.

ren
strike

@rgb
“Is it colder because it is cloudier, or cloudier because it is colder? The pictures do not and cannot reveal that. All they can do is show that cloudier and colder tend to go together, which is surely no surprise”
You’re statement is correct for a summerday, but is wrong for winters, at least my european ones. They only get really cold without clouds. Maybe this is different in Your warmer regions?

I find it very interesting that the art proxy lines up quite well with IPCC Figure 7c. Does it mean anything? Maybe, maybe not. It may be more relevent to phsycology than climate science. ..
Also, I would love to see a rigourus test of the statment “The Cosmic effect is now established through rigorous attempts to disprove it, the proper scientific method.”

Greg

“These artists considered the conditions relatively normal, ”
Did they ? Do you have that via personal communication too, or are you channelling?

OK, so if you sorted the art by year (rather than epochs that we know existed), could you get a graph anything like the IPCC Figure 7c? The epoch meathod is kind of like hindcasting, which all of us sceptics hate.

Funny, these global-temperature-proxies-as-art things.
See, multiple real-world actual witnessed events like the River Thames Ice fairs and churches in the Alps being exposed from under (retreating) glaciers are NOT considered valid proxies, but undated other proxies …

Bob Ryan

Steven Mosher – perhaps the following rewording might help:
‘The problem as any theory of science will tell you is that theory is not only influenced by nature,
but more importantly theory is influenced by other theory.
That is, theory not only can imitate nature it can imitate other theory. This is known as paradigm lock.
Until you can quantify the extent to which theory imitates other theory rather than its subject, you don’t have anything.’
There – that’s better. This is something some really great philosophers have spoken and written about: Thomas Kuhn, Imre Lakatos, David Papineau to name just three that spring to mind. I commend them to you.

Avi ben Barzel

Mr Mosher (April 24, 2014 at 1:18 pm) is partially right. Art often imitates art; it’s typically derivative. But from the Renaissance on, Western artists made serious efforts to depict nature with as much representation as they could. They were not monks copying icons in candle-lit scriptoriums, but went outdoors in all sorts of weather and quickly made working sketches of the natural environment before investing months of work on their great canvasses.. No, not evidence perhaps, but certainly a fascinating and pleasingly elegant hypothesis by Mr Ball.

Steven Mosher says:
April 24, 2014 at 1:18 pm
“That is, art not only can imitate nature it can imitate other art. This is known as artistic influence.”
As a plein air painter of 30+ years I would add that artist also are known to add clouds to a clear sky for interest. The next guy might just leave out any clouds. Some painted the sky in the studio to save time on location. The most you could say from the historical paintings is at some time they saw a sky some where like the one in the picture.

Duster

… Correlation between sunspot numbers and global temperature was known for decades, but with no proven mechanism it was correctly set aside. …
This is patently false. Indication of a nonrandom association between phenomena suggests a causal linkage. The linkage may not be even remotely as a simple as a change in one “causes” a change in the other. So, ideally rather than set aside investigation of correlated phenomena, it is ideal to look into determining if the correlation is real, then is it does appear to be real, a search for mechanism should be made. Invoking “no proven mechanism” is laziness, not science.

I still prefer the solution that solar variations affect tropopause heights differentially above equator and poles so as to change the length of the lines of air mass mixing and thereby affect global cloudiness.
The effect is seen in the shifts between zonal and meridional jet stream tracks.
Cosmic ray changes are a mere correlation with little or no causative significance.

Henry Clark

Dozens of papers on the observed climate influence of cosmic rays are listed and described under http://www.co2science.org/subject/s/subject_s.php among other sources.
For example:
Harrison, R.G. and Stephenson, D.B. 2005: “Across the UK, on days of high cosmic ray flux (above 3600×10^2 neutron counts per hour, which occur 87% of the time on average) compared with low cosmic ray flux, (i) the chance of an overcast day increases by 19% +/- 4%, and (ii) the diffuse fraction increases by 2% +/- 0.3%.”
Dergachev et al 2004: Known data “proves that cosmic rays were the main factor affecting the weather and climate during tens of thousands of years.”
A number of correlation plots, even down to quantities like drift ice in proxy data spanning thousands of years, are shown in a Kirkby paper: http://arxiv.org/pdf/0804.1938v1.pdf
And others are in my usual grand image and plot compilation which includes a number of additional references: http://tinyurl.com/nbnh7hq
So this article looking at art must be placed in context: It is a mildly interesting albeit relatively very weak observation, yet for a strong case with vastly stronger other evidence.
Recognizing the solar cosmic ray influence on climate is far more dangerous to the CAGW movement than, for instance, skeptics just blaming variation in the global temperature index on that in another temperature index (the AMO), and accordingly it has been particularly targeted. As extremely illustrated in http://hidethedecline.eu/ with example after example of original temperature and climate history, the foundation of the CAGW movement has been rewriting the past, rewriting data, and dishonesty. (Note that site has not been linked on WUWT’s list of top skeptic sites, a major omission).
The common claim that global warming is of huge magnitude relative to the change in forcing is untrue: All of global warming over the past century was about a <=~ 0.2% change in absolute Kelvin temperature (where global average temperature, of around 15 degrees Celsius, is around 298 Kelvin), whereas the change in solar-CRF forcing was large enough to primarily cause that at a small climate sensitivity. For example and to further show an example of the co2science site discussion:
"Next, based on information that indicated a solar activity-induced increase in radiative forcing of 1.3 Wm-2 over the 20th century (by way of cosmic ray flux reduction), plus the work of others (Hoyt and Schatten, 1993; Lean et al., 1995; Solanki and Fligge, 1998) that indicated a globally-averaged solar luminosity increase of approximately 0.4 Wm-2 over the same period, Shaviv calculated an overall and ultimately solar activity-induced warming of 0.47°C (1.7 Wm-2 x 0.28 C per Wm-2) over the 20th century.
Added to the 0.14 C of anthropogenic-induced warming, the calculated total warming of the 20th century thus came to 0.61 C, which was noted by Shaviv to be very close to the 0.57 C temperature increase that was said by the IPCC to have been observed over the past century.
Consequently, both Shaviv’s and Idso’s analyses, which mesh well with real-world data of both the recent and distant past, suggest that only 15-20% (0.10 C/ 0.57 C) of the observed warming of the 20th-century can be attributed to the concomitant rise in the air’s CO2 content.

Dozens of papers on the observed climate influence of cosmic rays are listed and described under http://www.co2science.org/subject/s/subject_s.php among other sources.
For example:
Harrison, R.G. and Stephenson, D.B. 2005: “Across the UK, on days of high cosmic ray flux (above 3600×10^2 neutron counts per hour, which occur 87% of the time on average) compared with low cosmic ray flux, (i) the chance of an overcast day increases by 19% +/- 4%, and (ii) the diffuse fraction increases by 2% +/- 0.3%.”
Dergachev et al 2004: Known data “proves that cosmic rays were the main factor affecting the weather and climate during tens of thousands of years.”
A number of correlation plots, even down to quantities like drift ice in proxy data spanning thousands of years, are shown in a Kirkby paper: http://arxiv.org/pdf/0804.1938v1.pdf
And others are in my usual grand image and plot compilation which includes a number of additional references, in the link in my name.
So this article looking at art must be placed in context: It is a mildly interesting albeit relatively very weak observation, yet for a strong case with vastly stronger other evidence.
Recognizing the solar cosmic ray influence on climate is far more dangerous to the CAGW movement than, for instance, skeptics just blaming variation in the global temperature index on that in another temperature index (the AMO), and accordingly it has been particularly targeted. As extremely illustrated in hidethedecline.eu with example after example of original temperature and climate history, the foundation of the CAGW movement has been rewriting the past, rewriting data, and dishonesty. (Note that site has not been linked on WUWT’s list of top skeptic sites, a major omission).
The common claim that global warming is of huge magnitude relative to the change in forcing is untrue: All of global warming over the past century was about a <=~ 0.2% change in absolute Kelvin temperature (where global average temperature, of around 15 degrees Celsius, is around 298 Kelvin), whereas the change in solar-CRF forcing was large enough to primarily cause that at a small climate sensitivity. For example and to further show an example of the co2science site discussion:
"Next, based on information that indicated a solar activity-induced increase in radiative forcing of 1.3 Wm-2 over the 20th century (by way of cosmic ray flux reduction), plus the work of others (Hoyt and Schatten, 1993; Lean et al., 1995; Solanki and Fligge, 1998) that indicated a globally-averaged solar luminosity increase of approximately 0.4 Wm-2 over the same period, Shaviv calculated an overall and ultimately solar activity-induced warming of 0.47°C (1.7 Wm-2 x 0.28 C per Wm-2) over the 20th century.
Added to the 0.14 C of anthropogenic-induced warming, the calculated total warming of the 20th century thus came to 0.61 C, which was noted by Shaviv to be very close to the 0.57 C temperature increase that was said by the IPCC to have been observed over the past century.
Consequently, both Shaviv’s and Idso’s analyses, which mesh well with real-world data of both the recent and distant past, suggest that only 15-20% (0.10 C/ 0.57 C) of the observed warming of the 20th-century can be attributed to the concomitant rise in the air’s CO2 content.

asybot

Growing up in Holland during my days in Art and History classes the depictions of the Little Ice Age were everywhere, There was also a definite cold period from the early 50’s to mid 60’s, I remember skating nearly every winter as a child from 55-66, since then not so much just the last few years there seems to be an increase again in the outdoor activity.

Johan

I’m not a painter but an amateur photographer, and I abhor clear blue skies. Clouds can add so much more drama to a scene.
All very interesting, but hardly convincing.

Ed, Mr. Jones

Mosher,
Was that Audubon guy interpreting art, or nature? When an artist desires to add elements not integral to or impacting on the ‘subject’, can we say they are likely or unlikely to use that which is at hand?
Unrelated: Those who dismiss the impact of clouds on global temperatures would likely dismiss the impact of umbrellas on midsummer, midday, tropical beach habitability – as well as on same in New England, US in mid April.

Tonyb

There was a study completed this year to ascertain if old paintings could depict such things as the aerosols from historic volcanic eruptions.
Some artists, like turner, are known to depict colours naturally, and it is reasonable to suppose that similar artists would depict what they saw.
The study is here
http://www.decodedscience.com/artists-works-provide-valuable-historical-information-climate-scientists/43968
Tonyb

unlikely any research money would go into finding triggers of mini ice ages or triggers for interglacial warming as they would probably demonstrate co2 is not a cause of anything? better the billions are spent backing up the settled science

Lawrence13

Jon said
“Sorry, I’m not convinced. Artists are out to make a buck like everyone else, When one local artist has got rich by painting cumulonimbus clouds, others will follow suit. When the public gets sick of cumulonimbus they’ll paint cirrus, or clear skies, or whatever sells. Paintings aren’t done on the spot, immediately, like photographs. The main details are sketched in and the less important stuff — like clouds — is usually added later in the studio.
This is like saying that two-dimensional people were commonly found in Egyptian times and during the Cubist period.”
I think sometimes we think the way we’ve lived in the last several thousand years has been forever but it hasn’t and art like everything else in human existence has slowly, slowly dragged and developed has humans existed literally in mud but surely the evolution of artists up until the 17/18 century was to try and develop the skills to depict reality as best as possible. I say try a because court painters would have to have the skill not only the paint realistically but in a flattering way. However portrait painting was different from landscape and I’m sure cloudy skies weren’t painted for their popularity and I’m sure that most artists were either commissioned by those with clout and money but not the public in general. Saying that as I’ve already mentioned I doubt rich/royal commissions had a proviso that clouds must be included and the scenes like the ‘census at Bethlehem and hunters in the snow. In fact Bruegel was given a commission in 1565 to actually paint the seasons .
I mean Egyptian two dimensional imagery was down to the lack of artistic knowledge and skill and trends like cubism came surely when the body of knowledge of art could paint/draw every subject matter with fantastic realism and accuracy and besides the camera came along. So I would say I believee most artist in the period we are talking about painted as accurately as they could based on their experience, If you look a Bruege’ls ‘Procession to Calvary’ it’s still bleedin’ cloudy!!!
http://en.wikipedia.org/wiki/File:Pieter_Bruegel_d._%C3%84._007.jpg

Guest essay by Dr. Tim Ball
– – – – – – – – – – – –
Tim Ball,
Thinking about the analysis of art versus the climate was enjoyable.
Thank you for the stimulation to do so.
John

‘Svensmark’s Cosmic Theory’
This one is so easy to debunk!
‘This one is important…the Sun doesn’t alter much, [the theory says] the Sun modulates the cosmic rays, the cosmic rays modulate the clouds, the clouds modulate the temperature, so the Sun amplified hugely… but we have reasons to believe it’s a fine tuning knob…the cosmic rays came streaming in…we had a big cosmic ray signal and the CLIMATE IGNORES IT and it’s just about that simple, these comic rays didn’t do enough for you to see it, so it’s a fine tuning knob’. R Alley, AGU>
[ http://www.youtube.com/watch?v=PgAuMWDHy30 ]

george e. conant

Clouds insulate , In day time heating the shade of clouds notably casts a cooler temp at ground level than direct sun, at night the clouds trap heat below them providing warmer night time temps than when night sky is clear. I experience this every day……

FrankK

Steven Mosher says:
April 24, 2014 at 1:18 pm
On the science there is no connection between GCRs and clouds. Looking at the highest resolution data we have at 12 different pressure levels, I find nothing. zip. nada. zero.
——————————————————————————————————
Could you please reference your paper or document on this finding Mr Mosher ?

albertalad

We can’t get the AGW fanatics to understand simple models – or actual satellite data – you know this is so far beyond their understanding you might want to start with something simple like coloring between the lines with crayons.

Johan

Lawrence13 says
“I mean Egyptian two dimensional imagery was down to the lack of artistic knowledge and skill ”
No, it wasn’t. For religious reasons they had to draw a body as completely as possible, because if e.g. a finger was missing from the painting, that person would be missing a finger in the hereafter.

R. de Haan

A really great article. Thank you very much Dr. Ball, nice work.

taxed

l have a interest in both landscape photography and weather watching.
By looking at the painting of “The Great Frost 1683” its clear the artist was painting the sky;s he was seeing at the time. They are so detailed l can get a good idea of the weather patterns at the time of the painting. The painting suggests to me that there was a Greenland high in place with area’s of low pressure moving along or sitting to the east of the UK.
Rather like what happened in late Nov / early Dec of 2010.

Pamela Gray

Sorry. Epic fail. The data is not random but a highly filtered group of paintings that rose to the top well enough to not be thrown away. Such filtered data is like Mann’s selective use of trees. Besides that, the uncontrollable variables involved in the development of the paintings dictate that 1000’s of paintings would be needed.
If anything, this post displays the pitfalls one can stumble into when one does not have a proper graduate level education in statistical analysis.

Gary Hladik

Ashby Manson

As fun as this article was to read, as an artist I’m going to hit the buzzer. Artist will ad or subtract clouds in response to artistic taste and temperament. Baroque and Gothic art will have differing levels of clouds depending on style. Maybe exclusively using nature studies would get better results, but…I’m not buying it.