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If you think it’s been cold here lately better brace yourself. According to a group of international scientists making presentations last week at the National Astronomy Meeting in Llandudno, Wales, we are in for a period of much lower temperatures than normal due to a decreased output from the Sun.

While their announcements seem out of place with the controversial issue of “global warming,” one has to look at the data accumulated over the last 50 years, especially in the area of sunspot activity.

Since the beginning of the space age we have been able to send rockets well above the atmosphere that blankets our planet and measure very accurately the luminosity of the Sun. Doing so allows us to see if the energy output varies with solar sunspot activity. To the surprise of logical thinking, it has been found that the Sun radiates about 0.1 percent less energy when its surface is clear compared to when many sunspots dot its face.

Now, this tiny amount of drop may not seem like a lot, but consider what has happened in the past when sunspot activity ground to a halt. Starting in about 1650 and for roughly 60 years thereafter, there were virtually no sunspots on the Sun at all. Scientists call this the Maunder Minimum, named after the husband and wife astronomer team who gathered the data that listed this scarcity.

Remarkably, it has been found that the Maunder Minimum corresponds to a peculiar climate period on Earth called The Little Ice Age when intensely cold winters hit Europe and North America with devastating results. When sunspots were absent solar output fell and so did temperatures on Earth — an average of four degrees F cooler — enough to freeze rivers and canals in Northern Europe and wipe out cereal production in Iceland. Also recorded with this drop were famines in France, Norway and Sweden caused by short growing seasons.

About the only good outcome of colder winters were trees producing denser wood, which probably contributed to the superior tone of the Stradivarius violin made during that time.

In fact, the best quantitative evidence of long term variations in the level of solar activity comes from the field of radio-carbon dating that examines the variation in the carbon isotope C-14, found in all living things. Because C-14 is formed when a cosmic ray from the Sun strikes a nitrogen molecule in the atmosphere, it has been found that C-14 production is higher when sunspots are absent. By measuring the amount of C-14 in tree-rings, the energy output of the Sun can be plotted over time.

Measurements confirm that during the Little Ice Age there were only about 50 sunspots instead of the usual 40-50 thousand. A smaller number sunspots means less energy means colder winters.

Dr Helen Popova, a professor of physics at Moscow State University, has studied this effect and claims that diminishing sunspots for the last 50 years may bring a new Ice Age starting a decade from now. Let’s take a look.

This column’s chart shows the number of recorded sunspots over the last 150 years and you can plainly see some periodic trends. The 11-year sunspot cycle, discovered in 1843 by Samuel Schwabe stands out quite nicely. Astronomers say we have just completed Cycle 24. The first cycle started in 1745 when Rudolf Wolf formulated the rules for exactly tabulating the spots.

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Unfortunately, Cycle 24 did not generate the number of sunspots expected, and very few begin to appear immediately after the last minimum (in 2008) which is strange in itself.

Although the sunspot number within the 11-year cycle does hit zero, the period is not long enough to form anything but an average effect on our climate.

Not as well know is the 90-year sunspot cycle. You can see its profile on the chart with a peak in the year 1960. If you plot the peaks from this point forward, (neglecting 1970), it becomes obvious that another “minimum” is looming ahead in the future, perhaps by the year 2030. Because the 90-year cycle has a much longer time base, its effects will be of long duration. Decades probably.

According to Professor Popova, this new reduction of sunspot activity will lead to a drop in solar irradiance by 3W per square meter, causing significant cooling of Earth with very severe winters and cold summers.

One may question, besides the Maunder Minimum, has this happened before? Yes, but on a much longer and protracted timescale. The study of deuterium, a hydrogen isotope, in the Antarctic showed that there were five global warming periods and four Ice Ages in the past 400,000 years. What caused the previous warmings? You can’t blame humans because the first appeared on the Earth at the end of the Cambrian period 485,400,000 years ago. One has to admit that our Sun is a prime suspect and there is nothing we can do about it.

However, I will make a prediction: Watch for politicians in Washington to somehow propose a tax to offset this new cooling effect.

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Gary Hanington is Professor Emeritus of physical science at Great Basin College and chief scientist at AHV. He can be reached at or


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