Science Corner: Debate Flares Over the Intensity and Duration of Solar Cycle 24

The months go by and still the sun remains quiet. This current sunspot cycle was supposed to end in 2007 if the usual average solar cycle duration of 10.7 years prevailed. It may have ended last December, about 18 months late, but no one knows for sure. So far the scientists at the National Oceanic and Atmospheric Administration and at NASA are only projecting that what is called the solar minimum has occurred, but even this projection is in doubt since the sun has been quiescent throughout 2009.

That means we may be in year 13 of the last solar cycle number 23, which would strengthen the hand of those scientists who have been warning that a major global cooling is coming our way. And by ”œour”, they mean everybody and everything on the planet. And by ”œcooling”, some scientists are beginning to wonder if the earth is in for a replay of the Little Ice Age that culminated in 1640. This is why an otherwise obscure scientific discussion of the arcana of sunspots and the solar cycle is starting to get more serious attention. As many parts of the U.S. have just gone through their coldest July since 1891, evidence seems to be mounting that this current prolonged solar minimum may already be having an effect.

Our scientific understanding of the sun has advanced enormously compared even to 30 years ago, but a lot of what happens with the sun is still poorly understood, and certainly open to debate. As with anything to do with earth’s climate, serious disagreements can arise over basic data derived from what are now constant measurements of solar activity. Until this most recent solar cycle, the debate has usually not taken on alarmist tones, but clearly something not seen at least in 100 years is now occurring with earth’s fundamental source of energy and life.

Basic Solar Dynamics

The sun is a giant nuclear reactor which creates energy not by fission, as occurs in an atomic bomb where atoms are forced apart, but by fusion. At the core of the sun, hydrogen atoms are under intense pressure due to the sheer mass of the sun itself, and this pressure fuses two hydrogen atoms together. This reaction produces helium atoms and certain other particles, and since helium is much lighter than hydrogen, the difference consists of massive amounts of energy that are released in the form of light and heat. Some of this light is visible to us and produces daytime on earth, but other parts of the light spectrum like x-rays, ultraviolet, and radio waves are just as important though not visible. Certain atomic particles like protons are also released and they eventually reach the earth in the form of the solar wind, which would otherwise be dangerous to life on the planet if not for the protective atmosphere of earth.

While the nuclear fusion process is instantaneous in the core of the sun, the manner in which energy reaches the surface is anything but. The energy first churns about in the middle section of the sun known as the reactive zone, and then convection currents of light and hot gases transfer the energy to the surface, where it eventually escapes and reaches us. The convection zone is what concerns us here, because it is heavily influenced by the magnetic field generated by the sun’s huge mass and its gravity. Earth has its own magnetic field and magnetic poles, but the sun’s is 5,000 times greater. The magnetic field is expressed along magnetic lines that loop from the interior outwards and back again, and as these magnetic lines pass through the sun’s surface, they create patches that are cooler than the rest of the surface and visible to us as dark sunspots.

Sunspots always erupt in pairs, like a positive and negative pole of a magnet, and these pairs are often clumped together. Sunspots interfere with the convection zone at the surface, so that light and other forms of energy reach us on an irregular basis, which is important because it is this light and energy which heats the planet, allows for life transformational processes like photosynthesis, and creates weather (think how hurricanes become more powerful as they pass over warm ocean water). We on earth have a keen interest in the behavior of these sunspots and their interference with the sun’s transfer of energy.

Galileo was the first scientist to systematically observe and chart sunspots in 1611. Since then, there has been a steady observation of these phenomena, with a more precise monitoring process established around 1750 that is known as the modern era. What this observation revealed is that sunspots appear in different intensities according to a cycle that averages 10.7 years, but ranges from as short as 7 years to as long as 16 years. At the start of the cycle there are very few sunspots ”“ this is known as the solar minimum – and then sunspot production increases for about 5.5 years to reach a solar maximum. In an average cycle, 40,000 to 50,000 sunspots can occur, with 150 occurring at any one time.

It is not clear what drives the solar cycle, but magnetic fields are not stable and this might create the cycle. Earth’s magnetic field appears stable but really isn’t; every so often the field reverses itself and the north magnetic pole trades places with the south magnetic poles (these poles themselves shift position regularly, in a position close to but not coterminous with the geographic North Pole and South Pole). Something similar may be happening with the sun, but on a more rapid cycle that is equivalent to about 11 years on earth.

History of the Solar Cycle

We have four hundreds years of data regarding the solar cycle, which is reproduced in this chart:

Starting with the first complete solar cycle charted shortly after 1750, there have been 23 solar cycles numbered accordingly, and we are now about to enter cycle 24. These cycles are shown as blue on the chart, and the black line is the median number of sunspots in thousands (scale on the right) during each cycle. One thing that has been observed regarding the cycle is that longer cycles, such as cycle 4 ending right around the French Revolution, tend to lead to weaker cycles where sunspot production can be cut in half. The two weak cycles that occurred around 1800 ”“ 1835 are known as the Dalton Minimum, for the scientist who studied this period.

An even more interesting minimum production occurred from 1650 to 1725, known as the Maunder Minimum; these are identified as red on the chart. The lack of sunspots during the Maunder Minimum is not the result of fewer people looking at the sun during the pre-modern era of observations. Scientists today have confirmed through other measures of solar activity on earth, such as tree samples or deep ice samples, that the sun was remarkably quiet during this period. Summers were much shorter and cooler, and winters longer and more severe. Around 1640, no sunspots occurred at all, and this corresponds to the coldest recorded temperatures during what is known as the Little Ice Age.

Temperatures on earth appeared to drop significantly in the late 1500s, and by the time Shakespeare was at the peak of his powers in 1600 and Galileo was turning the new invention of the telescope towards the sun, a very pronounced cooling was being recorded in historical documents from Europe to China. Rivers in Europe routinely froze; glaciers expanded, snowfalls were noticeably heavier, and winter began around October with thaws beginning to occur in May. Crop production in Europe plummeted and famine was widespread for many years during the Little Ice Age, which lasted throughout the 17th century.

Icebergs traveled much further south in the Atlantic, and the complaints by the colonists in Jamestown about the bitter winter weather were not misplaced. In fact, colonization of North America may have slowed down because of the dramatic cooling during the 17th century. Henry IV of France initially supported expansion of the French colony at Port Royal in l605 at the top of the Bay of Fundy, but refused further expeditions of settlers to the colony due in part to the difficult conditions there. The Dutch established the fort of New Amsterdam at the southern tip of Manhattan in 1625; they reported that in the winters New York Harbor routinely froze over and it was possible to walk from Manhattan to Staten Island over the ice.

The circumstantial evidence that the Maunder Minimum, which coincided with the Little Ice Age, was its cause is very strong, and most climatologists and solar scientists agree that more than coincidence was involved. But there was also increased volcanic activity on the planet at the time, and this may have provided increased cloud cover to block out the sun and cool the earth. Some historians say a chain reaction, starting with the Black Death in the 14th century, which resulted in severe depopulation, which then led to widespread reforestation in Europe, might have contributed to global cooling.

But the Dalton Minimum also coincided with much harsher winters, and even solar cycle 20, which occurred in the 1970s and was a noticeably weak cycle, was accompanied by cooler weather. Newspaper articles at the time commented on the many record cold days and heavy snows, and scientific articles began to warn about an early return of the next ice age. As scientists have recently begun collecting ice samples from Antarctica and Greenland to study global warming, they are noticing that the earth was definitely colder during the Little Ice Age, and this was felt globally. This increases the possibility that the Maunder Minimum ”“ during which time the sun’s magnetic field repositioning seemed to shut down completely ”“ was the main cause of global cooling.

Is the Sun Entering a Quiet Period Again?

Originally the NASA and NOAA committee of solar scientists responsible for monitoring the sun and then reporting their opinions on the solar cycle to the federal government, believed that solar cycle 24 would arrive on time and be of average strength and length. One of these scientists, David Hathaway, has studied how hot gases in the convection zone are transmitted to the surface through conveyor belts located above and below the equator. Using sunspot data going back to the 19th century, he has determined that the conveyor belts are moving slower than ever. Given the time it takes for gases to reach the surface, he believes this next solar cycle will be typical, but cycle 25 afterwards will be noticeably quieter. He has averred that an event like the Dalton Minimum could happen again in the next two decades, but he would not go so far as to call for a Maunder Minimum.

Hathaway’s prediction has set off excitement within the cottage industry devoted to debunking global warming. One such organization in Florida, the Space and Science Research Center, immediately jumped on the Hathaway announcement as proof of what they have been saying all along ”“ that global warming is a hoax. The SSRC director John Casey, issued a press release that said in part:

There can no longer be any doubt that the Sun has entered an historic period of dramatically reduced activity which will bring us many long years of deep cold weather. This was predicted by me and a few other scientists around the globe but of course we were not taken seriously because of the politics of global warming and the refusal of many media outlets to print or telecast alternatives to the now discredited man made global warming concept. According to national and international sources that monitor the Sun, what is happening on and in the Sun is nothing short of record setting, astounding, and at the same time worrisome. The solar wind is at its lowest level in fifty years. The surface movement on the Sun has slowed to record rates and according to NASA’s previous announcements is ”˜off the bottom of the charts.’ Most telling is the current prolonged lack of sunspots between the normal 11 year solar cycles 23 and 24 which is about to set a one hundred year record for time without sunspots. NASA also has long since forecast that cycle 25 will be ”˜one of the weakest in centuries.” All of these events in combination leave little doubt that a ”˜solar hibernation’ lasting several decades delivering the coldest weather in over two centuries has in fact arrived.

Dr. Casey states that no one has taken him seriously, so should we now? When you are out in the scientific wilderness for decades you tend to grab on to whatever will accord you respectability, and mixing up solar cycle predictions with the global warming debate is an easy temptation. The weight of scientific evidence has been mounting over the years in favor of the hypothesis that CO2 emissions in the atmosphere are contributing to global warming (earlier attempts to debunk the very idea that warming is occurring have been abandoned by most of the global warming hoax crowd). Whether or not the solar cycle is slowing down or going into hibernation, does not negate the facts surrounding carbon emissions. Even the Indian and Chinese governments do not deny global warming and their own contribution to it; they merely present the crass argument that they too should now be allowed their turn, like the West, to industrialize rapidly by polluting the environment.

Most scientists involved in climatology agree with the global warming theories. Their view about the solar cycle is evolving as the science evolves. For example, recent research shows sunspot activity to be highly correlated with the warming of the Pacific Ocean, which in turn leads to the El Nino and La Nina phenomena. There may be many other such climatic correlations to be discovered. But what hasn’t been established yet is a direct link between global temperatures and the solar cycle, whereas the link between carbon emissions and temperature change is much more solid. Also, the degree of damage done by global warming could be catastrophic; a second Little Ice Age on the other hand would mitigate this damage but not prevent it. Moreover, the planet did survive and recover from the Little Ice Age. Global warming under the worst scenarios could cause changes lasting over 100,000 years.

What Do We Know as of Now?

1. Solar cycle 24 may have kicked off at the end of 2008. Some sunspots appeared then which had the requisite reversed magnetic polarity from sunspots in cycle 23, and this is one of the key bits of evidence that the solar cycle has reset. But since then, nothing much has happened, so the official U.S. government committee monitoring the sun is split on what is occurring.

2. Cycle 23 may therefore be continuing, according to some of these scientists, and if so we are entering an unusual, rare extension of the cycle. Cycle 24 under these conditions is likely to be quite weak, which could lead to temporary global cooling.

3. Even if cycle 24 has commenced, the follow-up in 2009 has been unusually weak and has caused those scientists who originally thought we were in for a typical cycle to downgrade their expectations for the number of sunspots to be produced in cycle 24. Along with this downgrade comes predictions that some global cooling might occur.

4. At least one scientific expert believes the follow-up cycle, number 25, will be very weak, possibly on the order of the Dalton Minimum. This would have even greater implications for global cooling.

5. No one, scientist or otherwise, really knows what is happening now with the sun. There are 23 data points to the solar cycle, not counting what occurred during the Maunder Minimum. These 23 data points are too few to draw statistical conclusions of any reliability. No one can say for sure what cycle 24 will look like until it is well underway, and no one can accurately predict another Minimum period other than to say that what has happened with the sun in the past should in all probability happen again. Maybe the sun’s magnetic field is even able to move into hibernation for as long as 100,000 years; that could explain earth’s Ice Ages.

6. Whatever is happening with the sun, there is no reason to take these events as evidence or proof that manmade global warming is not occurring, much less that the solar cycle has caused global warming. At best, solar cooling might mitigate the effects of global warming, but at least we can do something about global warming as a manmade event. We can do nothing about the solar cycle.

7. There does seem to be some temporary cooling going on in 2008 and 2009, though this is of little comfort to places like Texas under severe drought, or the northwestern U.S. states suffering a record high summer temperature. This cooling may be related to the current minimal sunspot activity.

8. Finally, nothing is more vital to the existence of life on earth than the sun, so it well behooves us even as non-scientists to be mindful of the solar cycle. It certainly behooves government to spend money monitoring, debating and reporting on solar activity. Since mankind began exploiting electromagnetic radiation for use in radios, satellite communications, cell phones, power lines, and many other applications, solar activity has taken on vital importance because all these uses could be disrupted or permanently damaged.

It would be fun to end this article with a rousing cheer for the sun, in the hopes that a normal sunspot cycle will commence soon. But the only operative adage we can take when it comes to the sun is que sera sera. We can only wait and see what will happen. We can’t even prepare for a temporary 50 year global cooling period until it is upon us. And we should certainly not reduce our vigilance in reducing carbon emissions into our own atmosphere.

Still, something’s happening out there that is more than just interesting ”“ it might be earth-shaking. We shall see whether a phenomena as obscure as sunspots begin to affect all our lives in unexpected ways.

This post was read 175 times.

About author View all posts Author website


Numerian is a devoted author and poster on The Agonist, specializing in business, finance, the global economy, and politics. In real life he goes by the non-nom de plume of Garrett Glass and hides out in Oak Park, IL, where he spends time writing novels on early Christianity (and an occasional tract on God and religion). You can follow his writing career on his website,

25 CommentsLeave a comment

  • But I don’t think we see a breakdown of the cycles just yet. There was a monster of a sunspot observed recently and activity picked up significantly in July.

    I just happened to get my telescope out of storage yesterday because we had such a clear sky with a beautiful moon and I new the kids would be delighted to look at it up close. Later last night I just by chance pointed it at Jupiter and was surprised to count five “moons”. I guess when the weather clears up I will try some sunspot hunting 🙂

  • The monster sunspot is new and significant but I know there is the technical definition that sunspots have to be appear above and below the 20 degree latitudes. Whether this one qualifies I haven’t read yet. Perhaps that will be considered a quibble.

    The other ones in your reference fit that definition but the polarity is from the old cycle 23 so that has disappointed scientists. We should well be seeing sunspots with cycle 24 polarity by now. Moreover, the new ones tend to disappear in hours. The pictures, by the way, are fabulous in your link.

    As to the five moons around Jupiter, Galileo only found four and I am sure would be intrigued by this sudden appearance. The other interesting thing happening there of course is the debris cloud that shows up on your picture as a black spot. Over in the states – to show you what sort of news gets any attention in America when it comes to astronomy – all the headlines talk about a mysterious “alien object” hitting Jupiter. People probably wouldn’t read the story if a UFO weren’t involved.

  • “Helium is much lighter than hydrogen” I’m going to be picky.

    Helium is heavier than hydrogen. There is a property of elements called the “mass defect”.

    The mass of the helium atom (two protons and two electrons) is slightly lower that one would predict from the mass of the hydrogen atom (one proton & one electron).

    It’s this mass defect that is converted into energy when two hydrogen atoms are fused (fusion) into one helium atom.

    Similarly when a large atom (for example: Uranium) is split there is a corresponding mass defect in fission.

    The element with the lowest mass defect is Iron – which is also the core of burnt out start (reactors which have consumed all their fuel).

    Dear reader, you are driving surrounded by matter from a dead star.

  • I remember reading somewhere that all matter ultimately originates from stars, or maybe that we are one of the results of the process by which stars are created. I use to own a Chevy Nova so I can definitely relate to driving surrounded by matter from a dead star.

    I thought I was already straying into dangerously detailed descriptions, so I overly-simplified this “Solar science for dummies” statement: “The helium-4 atoms are less massive than the two hydrogen atoms that started the process, so the difference in mass was converted to energy as described by Einstein’s theory of relativity (E=mc2).” The mass defect concept is probably a better way to explain things, starting out with one simple atom of helium and hydrogen each.

    I also left out the part of the sun having fuel for a few billion or so years of existence, hoping that people understood we as a species probably wouldn’t be around when the final reckoning occurs.

  • Probably should have linked to the underling report. Just happened to point my telescope at Jupiter when there’s a rare eclipse about to happen. The star lines up with the plane of the visible moons giving the perfect appearance of a fifth moon. Quite a treat.

  • Yes, this diagram shows that nuclear fusion only produces energy up to iron.

    It is believed that the only natural high energy processes that produce elements further down the periodic table are violent cosmic events such as super-novae. Since our organism requires heavier elements than iron to function our existence is indirectly linked to this cosmic genesis.

  • …and the wingnuts will remain in denial of our effect on the earth’s climate. The wisdom of Lovelock’s Gia Hypothesis encourages the thought that we can hurt the earth but ultimately we will destroy only ourselves. I live at 14deg. north latitude and over the last 3 years the climate, oops, I mean weather(sorry), here has been cooler with far fewer 38 – 40c days. I’ve been here just short of 7 years. Not scientific but interesting never the less. More rain as well. We do live in interesting times; never thought I have to contemplate winter heating… 😉

  • The DoD announced this is an Al-Quaeda plot, because Indonesia is a Muslim country. The Volcano is clearly the work of local insurgents.

    The DoD is send a marine task force to Krakatoa to subdue the volcano.

    The marines are equipped with 3,000,000 gallons of beer to douse the insurgent volcano. The DoD expect some of the beer to be applied directly to the volcano with the SPILLS beer delivery system. The remainder will be deliver by other, secret, means and the marines are instructed not the discuss the secret method and to keep zipped up.

  • Who would have thought. Eye searingly busy site but lots of data. Nice to see that there a still plenty of ham radio folks out there who care about this.

  • There are many Solar Cycle 24 websites and blogs but this is one of the best visually, though your description as “eye searingly busy” is poetic and correct.

    The NOAA sunspot prediction model for Cycle 24, as well as Dr. Hathaway’s model from NASA, are included on their dashboard and both call this month to be the bottom. By October sunspots should be picking up. The few sunspots that are currently seen are showing up as predicted by these two models, so on this basis activity should be accelerating almost immediately though gradually.

  • Do you really want to see what happens when a volcano pukes?

    “The best-informed man is not necessarily the wisest. Indeed there is a danger that precisely in the multiplicity of his knowledge he will lose sight of what is essential.”

    – Dietrich Bonhoeffer

  • ARRL, By Steve Nichols, G0KYA, October 30

    Well, what a week it has been. The solar flux hit 82.3 on Tuesday, the highest recording yet since the first-observed “new cycle sunspot” in January 2008, the “official” visual start of Solar Cycle 24. Even as I write this, the flux is still at 80, thanks to sunspot region 1029, so let’s hope that it is a sign of better things to come. Sunspot numbers for October 22-28 were 0, 30, 21, 28, 29, 29 and 26 with a mean of 23.3. The 10.7 cm flux was 71.6, 72.9, 75.6, 75.5, 81.3, 81.5 and 79.9 with a mean of 76.9. The estimated planetary A indices were 14, 8, 8, 5, 3, 3 and 2 with a mean of 6.1. The estimated mid-latitude A indices were 12, 7, 5, 3, 3, 2 and 3 with a mean of 5. The region (1029) produced several B-class solar flare events and a single C2.2 class flare on the 28th, but luckily CQWW SSB was unaffected for the most part.

    NASA’s STEREO “behind” spacecraft is not showing any new spots coming around the solar rim, but we live in hope…

    Comparison of Sunspot-Number Indices

    They sicken of the calm, who knew the storm.

  • RealClimate, By Georg Feulner, June 19

    During a meeting of the Solar Physics Division of the American Astronomical Society, solar physicists have just announced a prediction that the Sun might enter an extended period of low activity (a ‘grand minimum’) similar to the Maunder Minimum in the 17th century. In this post I will explore the background of this announcement and discuss implications for Earth’s climate.


    The Maunder Minimum falls within the climatically cooler period of the “Little Ice Age”, during which temperatures were particularly low over continents in the Northern hemisphere (especially in winter). It has long been suspected that the low solar activity during the Maunder Minimum was one of the causes of the Little Ice Age, although other factors like a small drop in greenhouse gas concentrations around 1600 and strong volcanic eruptions during that time likely played a role as well.

    Solar physicists do not yet understand how an extended solar-activity low like the Maunder Minimum arises. Yet there is recent observational evidence for an unusual behavior of the Sun during the current cycle 24, including a missing zonal wind flow within the Sun, decreasing magnetic field strength of sunspots and lower activity around the poles of the Sun. These observations prompted Frank Hill and colleagues to suggest that the Sun might enter a new Maunder-like minimum after the current 11-year cycle ends (i.e. after 2020 or so).

    It remains to be seen whether this prognosis turns out to be true (there have been some doubts expressed), but since grand minima of solar activity did occur in the past, it is certainly interesting to explore what effects such a minimum might have on 21st century climate if it did occur. This is precisely the question Stefan Rahmstorf and I investigated in a study published last year (see also our press release. (Earlier estimates for the size of this effect can be found here and here.) In our study we find that a new Maunder Minimum would lead to a cooling of 0.3°C in the year 2100 at most – relative to an expected anthropogenic warming of around 4°C. (The amount of warming in the 21st century depends on assumptions about future emissions, of course).

    According to these results, a 21st-century Maunder Minimum would only slightly diminish future warming. Moreover, it would be only a temporary effect since all known grand solar minima have only lasted for a few decades. Critics of this result might argue that the solar forcing in these experiments is only based on the estimated change in total irradiance, which might be an underestimate, or that does not include potential indirect amplifying effects (via an ozone response to UV changes, or galactic cosmic rays affecting clouds). However, our model reproduces the historic Maunder minimum with these estimates of solar irradiance. Furthermore, even if one multiplied the solar effects by a huge factor of 5 (which is unrealistic), no absolute cooling would take place (the temperatures would be temporarily cooler than the base scenario, but the trends would still be warming).

    One owes respect to the living. To the dead, one owes only the truth.

Leave a Reply