Sunspot Cycle Length vs Temperature Anomaly │ Jasper Kirkby

The sunspot cycle length as a measure of the Sun's activity:
Variation during the period 1861 - 1989 of the sunspot cycle length (solid curve)
and the temperature anomaly of the Northern Hemisphere (dashed curve).
The temperature data from the IPCC.

Jasper Kirkby (1998) - The sunspot cycle length averages 11 years but has varied from 7 to 17 years, with shorter cycle lengths corresponding to a more magnetically-active Sun. A remarkably close agreement was found between the sunspot cycle length and the change in land temperature of the Northern Hemisphere in the period between 1861 and 1989 [update HERE]. The land temperature of the Northern Hemisphere was used to avoid the lag by several years of air temperatures over the oceans, due to their large heat capacity. This figure covers the period during which greenhouse gas emissions are presumed to have caused a global warming of about 0.6°C. Two features are of particular note: firstly the dip between 1945 and 1970, which cannot be explained by the steadily rising greenhouse gas emissions but seems well-matched to a decrease in the Sun's activity, and secondly the close correspondence between the two curves over this entire period, which would seem to leave little room for an additional greenhouse gas effect.

[...] The observation that warm weather seems to coincide with high sunspot counts and cool weather with low sunspot counts was made as long ago as two hundred years by the astronomer William Herschel who noticed that the price of wheat in England was lower when there were many sunspots, and higher when there were few. See also HERE  

Data: SILSO Royal Observatory of Belgium.

Sunspots - The Real Cause of Higher Grain Prices | Tom McClellan

Tom McClellan (Jul 27, 2012) - Sunspots are a big driver for wheat prices. Various pundits are putting out stories blaming the drought in the plains states on global warming [...] A better explanation for the drought, and the ensuing spike in grain prices, is that this is all part of the normal 11-year sunspot cycle. But to find that relationship in the data is what the story is about. The first point to understand is that sunspot activity has now been scientifically linked to changes in cloud formation. When the sun is more active, the charge particles streaming out from sunspot activity help to sweep away cosmic rays that might otherwise hit earth's atmosphere, where they play a role in cloud formation. [see also HERE] 

 

Once you get past that more difficult scientific hurdle of understanding that cosmic rays and clouds are related, it is pretty easy to understand that less cloud formation is related to less precipitation, and thus poorer growing conditions for rain-irrigated crops. That is what we are seeing with this year's drought, and it has been pushing up grain prices accordingly. Looking across the last hundred years of price data on wheat, it can be difficult to see the relationship between the sunspot number and wheat prices. Part of this comes from the fact that there are other factors which sometimes act upon crop yields and thus grain pricing. But a big factor is that the units we use to measure wheat prices, i.e. US dollars, can vary themselves, causing the relationship with sunspots to sometimes be disguised by what the dollar itself is doing. 

 

If we look at the history of these two sets of data before the modern era of floating currency exchange rates, we can better see how they were correlated. This chart shows raw wheat prices, un-adjusted for the value of the dollar. The sunspot number data is shifted forward by 2 years to reveal that bottoms and tops in the sunspot number tend to be followed a couple of years later by bottoms and tops in wheat prices. This relationship got into some trouble in the middle part of the chart, when President Roosevelt's New Deal price fixing artificially inflated wheat prices. The intention in the 1930s was to benefit farmers by keeping wheat prices up.  

 

That effort switched during WWII to the government putting a cap on all prices, including wheat, to support the war effort. Rationing of food, fuel, and other items took over for market forces. Additional trouble came in the 1970s, when the Arab Oil Embargo pushed up oil prices in 1973-74, reducing acreage under cultivation. Then later in that decade, the rising value in the dollar pushed down the dollar price of most commodities compared to prices in other currencies. So using dollars to see the normal cyclical relationship in price data became problematic.

All of this explanation brings us (finally!) back to the lead chart above. In [the above] chart, I have adjusted the dollar price of wheat, multiplying it by the US Dollar Index, which was created back in 1971. This mathematical step produces a unit-less measure of the value of wheat by factoring out the dollar's movements. Doing this allows us to better see how the peaks and troughs in wheat prices have been related to the sunspot cycle. 

 

I want to emphasize again that the sunspot number is shifted forward in that chart by 2 years, to reveal its leading indication for how wheat prices will behave. The conclusion from this is that the upward move in the value of wheat right now is just following the swoop upward in the sunspot number that began in 2009. We should expect to see generally rising prices for wheat and other grains until about 2 years after the sunspot cycle has peaked, a peak which has not even happened yet.

On the Insignificance of Herschel’s Sunspot Correlation | Jeffrey J. Love

William Herschel started to examine the correlation of solar variation and solar cycle and climate. Over a period of 40 years (1779–1818), Herschel had regularly observed sunspots and their variations in number, form and size. Most of his observations took place in a period of low solar activity, the Dalton minimum, when sunspots were relatively few in number. This was one of the reasons why Herschel was not able to identify the standard 11-year period in solar activity. Herschel compared his observations with the series of wheat prices published by Adam Smith in The Wealth of Nations.In 1801, Herschel reported his findings to the Royal Society and indicated five prolonged periods of few sunspots correlated with the price of wheat. Herschel's study was ridiculed by some of his contemporaries but did initiate further attempts to find a correlation. Later in the 19th century, William Stanley Jevons proposed the 11-year cycle with Herschel's basic idea of a correlation between the low amount of sunspots and lower yields explaining recurring booms and slumps in the economy. Herschel's speculation on a connection between sunspots and regional climate, using the market price of wheat as a proxy, continues to be cited. However, according to a study of Jeffrey J. Love of the USGS the evaluation is controversial and the significance of the correlation is doubted:

Jeffrey J. Love (Aug 27, 2013) - Our finding is that Herschel’s hypothesis is statistically insignificant [...] All of the data Herschel discussed in his 1801 paper were collected prior to 1717, during the Maunder Minimum and long before his paper was published. His identification of five durations of time with few sunspots and inflated wheat prices and five other durations that might have had sunspots and which had deflated prices [Herschel, 1801, pp. 313-316] would be an unlikely realization of binary statistics, but it is not clear whether or not Herschel was inspired to state his hypothesis after inspection of these data. Having said this, Herschel acknowledged that predictions based on his hypothesis “ought not be relied on by any one, with more confidence than the arguments ... may appear to deserve” [Herschel, 1801, p. 318]. Today, we have considerably more data than were available to Herschel; these were collected both before and after he stated his hypothesis, and they can be used for both retrospective and prospective testing.  For  London wheat  prices  both before 1801 and, separately, after 1802, binary significance probabilities and Pearson correlations and their effective probabilities are [...] indicative of statistical significance. While solar irradiance may affect global climate, from our analysis of data of the type considered by Herschel, we conclude that historical wheat prices are not demonstrably useful for inferring past sunspot numbers, and, conversely, sunspot numbers are not demonstrably useful for predicting future wheat prices.

The Effect of Sunspot Activity on the Stock Market | Charles J. Collins

Charles J. Collins (1965) - Solar phenomena have been a source of scientific interest and investigation since Sir William Herschel, in 1801, found a correlation between sunspot activity and terrestrial phenomena [...] Modern science is giving considerable attention to solar phenomena in relation to disruption of the earth's magnetic field, to human health, and to weather, including rainfall, temperature, and cyclone frequency. The security analyst's interest is more directly concerned with the directly concerned with the effect of solar phenomena on business, and on speculation as evidenced by the ebb and flow of prices over our stock exchanges [This paper points] out one simple correlation of solar-stock market movements that will, fortunately, come to another test within the two or three years ahead. This is an apparent relationship between a recurrent phase of each sunspot cycle and an important stock market peak. The matter is of interest at this time for the reason that considerable attention is being given by students of the stock market as to when the broad advance that has been under way for a number of years is to reach a terminal point. This sunspot correlation, as discussed below, may throw some light on the subject. Briefly stated: It appears that an important market peak has been witnessed or directly anticipated when, in the course of each new sunspot cycle, the yearly mean of observed sunspot numbers has climbed above 50.

[...] Over the 94-year period under review, there were seven completed sunspot cycles, and it appears that an eighth was completed and a new cycle was started in 1964.During these eight cycles, not onlywas an important stock market peak concurrently witnessed (1881, 1892, 1916, 1936,1946, 1956)or directly anticipated (1906, 1929) by the above-50 count in sunspots, but, in four instances (1881, 1916, 1929, 1936), the designated peaks also marked the extreme or secular peaks for the entire sunspot cycle. The year 1890 seems an exception. In May of that year, the stock index reached its high of 5.62. In August 1892, the 5.62 level was again attained and, as concerns the yearly mean of the monthly stock indexes, the year 1892 peaked at 5.55, as compared with 5.27 for the year 1890 [...] In other words, in six instances, important stock market peaks and the sunspot climb above 50 came the same year, the two exceptions being 1906 and 1929. As to the 1906 exception, it will be noted, from the monthly range stock market chart, that the market peaked in January of that year, with December 1905 not far behind the January 1906 peak.

From a study of stock market history in relation to solar phenomena, a second theorem may be adduced: In each solar cycle, the largest stock market decline, in terms of percentage drop, comes after the sunspot number, on an annual basis, has climbed above 50. In the light of the foregoing observation, the 94 years of sunspot activity under review seems to occupy a rather narrow latitude for dogmatism. Thus, the preceding remarks should not betaken as a definitive prognosis of pending stock market behavior. Instead, they present a rather interesting correlation that has existed for a period of years between sunspot activity and major market peaks. Ergo, since the solar cycle is now at a point germane to this correlation, it seems worthwhile to present the previous relationship and await events, not without interest, of course, but mostly in the spirit of an enquiring attitude.

Originally printed in Financial Analysts Journal, November-December 1965; reprinted in Cycles Magazine in March 1966, and again in Cycles Magazine, Vol. 40, No. 3, September/October 1989]; editor's postscript of the 1989 reprint: "It is interesting to note the relation between above-50 crossingsand the stock market since 1965. In July 1966, the mean sunspot number moved above 50. The stock market shortly thereafter plunged in a major correction. In January 1978, the mean sunspot number again went above 50. The stock market, which had been in a downtrend, continued into a bottom after this date. In October 1987, the mean sunspot number went well above 50 to 60.~ and the 1987 crash followed. The mean sunspot number will next rise above 50 in about 1998."

Sunspots, Climate, Agriculture, Financial Markets, and War | The Big Picture

Most people think the Sun rests at the center of the solar system, and
that the planets orbit it. This is almost correct, but not quite (HERE).

Many cultures have historically believed that solar and extraterrestrial cycles shape collective behavior. Since the start of continuous sunspot tracking in 1755, research has focused on how these cycles affect climate, weather, and global markets. In the social sphere, some studies even link geomagnetic disturbances caused by the solar cycle to increased violence, revolutions, and the escalation of warfare (HERE). 

The Sun’s cyclic activity results from tidal and electromagnetic interactions with the planets, dominated by Jupiter and Saturn. These planets possess 92% of the total planetary mass and 86% of the system’s angular momentum. Their orbital positions significantly influence the solar system's barycenter; when in conjunction, they pull the barycenter well beyond the Sun’s 0.0044 AU radius, whereas in opposition, the barycenter returns to the solar interior. This orbital choreography creates a 178.770-year periodicity in the Sun’s motion around the center of mass. This cycle, consisting of 16 loops, is subject to a "torque cycle"—a periodic variance of ±1.05 years. Defined by nine synodic periods of Jupiter and Saturn (9×19.858=178.722 years), this cycle was famously utilized by Theodor Landscheidt to forecast sunspot activity.

 

The earliest hypothesis regarding the relationship between solar cycles and economic activity was proposed in 1801 by the German astronomer Wilhelm Herschel, who noted a correlation between sunspot activity and wheat prices. In 1875, British economist William Stanley Jevons expanded on this, suggesting that sunspots influenced business cycle crises. Jevons theorized that solar activity dictated Earth’s weather patterns, which subsequently impacted crop yields and the broader economy. However, a 1934 study by Carlos Garcia-Mata and Felix I. Shaffner re-examined these links within the United States. While they found no evidence to support Jevons’ agricultural hypothesis, they discovered a statistically significant correlation between solar cycles and fluctuations in non-agricultural business activity.

 

 

Solar maximums have served as reliable predictors of US recessions, accounting for 8 of the 13 economic downturns between 1935 and 2012. Historically, recessions tend to cluster around these peaks in solar activity; during this period, 8 recessions commenced within a specific window ranging from three months prior to 20 months after a solar maximum. The remaining five downturns, including the Great Recession of 2008–09, can be attributed to distinct geopolitical and systemic shocks. For instance, the brief contraction of 1945 and the recession of 1953–54 resulted from sharp reductions in government spending and military orders following World War II and the Korean War, respectively. Similarly, the 1974–75 recession was precipitated by the global oil crisis, while the 2008–09 financial crisis was triggered by the collapse of the subprime mortgage market and systemic failures in securitization.

 

Between 1948 and 2012, all six periods of solar maximum coincided with troughs in the US unemployment rate. Notably, these solar peaks appeared to mark a turning point: in each instance, the unemployment trend shifted from a steady decline to a rapid increase, typically reaching its peak two to three years after the sunspot maximum.

 

Reference:

Theodor Landscheidt (1981) - The Swinging Sun, 79-Year Cycle, and Climatic Change. 

Rhodes W. Fairbridge & James H. Shirley (1987) - Prolonged minima and the 179-yr cycle of the solar inertial motion.

Carsten A. Arnholm (2008) - The Planets could be Modulating Solar Activity.

Mikhail Gorbanev (2012): Sunspots, unemployment, and recessions, or Can the solar activity cycle shape the business cycle?