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James Marusek’s Forecast For Solar Cycle 25

February 11, 2018

By Paul Homewood



James Marusek has sent me his latest forecast for Solar Cycle 25, which includes the forecast as well as some background explanation.





I’ve highlighted some of the major points, but it is worth reading in full for those who are interested.


I. Introduction

The sun is the natural source of heat and light for our planet. Without our sun, the earth would be a cold dead planet adrift in space. But the sun is not constant. It changes and these subtle changes affect the Earth’s climate and weather.

At the end of solar cycle 23, sunspot activity declined to a level not seen since the year 1913. [Comparing Yearly Mean Total Sunspot Numbers]

The following was observed during the solar cycle 24:

1. The number of sunspots over the entire solar cycle decreased significantly by 50% or greater.

2. There were fewer solar flares and coronal mass ejections (CME’s), which produces Solar Proton Events (SPE’s) and geomagnetic storms on Earth. During the transition, beginning in July 2000, the sun produced 6 massive explosions in rapid succession. Each of these explosions produced solar proton events with a proton flux greater than 10,000 pfu @ >10 MeV. These occurred in July 2000, November 2000, September 2001, two in November 2001, and a final one in October 2003. And there hasn’t been any of this magnitude since.

3. The magnetic field exerted by the sun significantly weakened. The Average Magnetic Planetary Index (Ap index) is a proxy measurement for the intensity of solar magnetic activity as it alters the geomagnetic field on Earth. It has been referred to as the common yardstick for solar magnetic activity. Ap index measurements began in January 1932. The quieter the sun is magnetically, the smaller the Ap index. During the 822 months between January 1932 and June 2000, only one month had an average Ap index that dropped down to 4. But during the 186 months between July 2000 and December 2015, the monthly Ap index fell to 4 or lower on 15 occasions.

4. The number of Galactic Cosmic Rays (GCRs) striking Earth increased. GCRs are highenergy charged particles that originate outside our solar system. They are produced when a star exhausts its nuclear fuel and explodes into a supernova. The Sun’s magnetic field modulates the GCR flux rate on Earth. Cosmic rays are deflected by the interplanetary magnetic field embedded in the solar wind, and therefore have difficulty reaching the inner solar system. The effects from the solar winds are felt at distance approximately 200 AU from the sun, in a region of space known as the Heliosphere. As the sun went quiet magnetically, the Heliosphere shrunk, and a greater number of these particles penetrated into the Earth’s atmosphere. The sun’s interplanetary magnetic field fell to around 4 nano-Tesla (nT) from a typical value of 6 to 8 nT. The solar wind pressure went down to a 50-year low. The heliospheric current sheet flattened. In 2009, cosmic ray intensities increased 19% beyond anything that was seen since satellite measurements began 50 years before.

5. In general, the sun’s total irradiance varies about 0.1 percent over normal solar cycles. But this variation is not linear across the entire radiation spectrum. Between 2004 and 2007, it was observed that the decrease in ultraviolet radiation (with wavelengths of 400 nanometers) was 4 to 6 times larger than expected, whereas the visible light (400-700 nanometers) showed a slight increase. This is significant because Solar UV flux is a major driver of stratospheric chemistry.

6. The upper atmosphere of Earth collapsed. The thermosphere ranges in altitude from 90 km to 600+ km above the Earth’s surface. During the depth of last solar minimum in 2008-2009, Impact 2018 2 the thermosphere contracted by the largest amount observed in at least the last 43 years. The magnitude of the collapse was two to three times greater than low solar activity could explain.

7. Solar radio flux during the peak of the solar cycle diminished significantly. The F10.7 index is a measure of the solar radio flux per unit frequency at a wavelength of 10.7 cm, near the peak of the observed solar radio emission. The solar cycle minimum produced the lowest F10.7 flux since recordings began in February 1947. 8. Sightings of noctilucent clouds (or night clouds) are appearing at lower latitudes. These clouds are formed from ice crystals in the extreme upper atmosphere, called the mesosphere. Noctilucent clouds (NLCs) were first reported by Europeans in the late 1800s. In those days, you had to travel to latitudes well above 50º to see them. Now, however, NLCs are spreading. In recent years they have been sighted as far south as Colorado and Utah in the United States.



II. Background

Solar Cycles Sunspots are dark spots that appear on the surface of the sun. They are the location of intense magnetic activity and they are the sites of very violent explosions that produce solar storms.

The sun goes through a cycle lasting approximately 11 years. It starts at a solar minimum when there are very few sunspots and builds to a solar maximum when hundreds of sunspots are present on the surface of the sun and then returns back to a solar quiet minimum. This cycle is called a solar cycle. We are currently in the solar minimum separating Solar Cycle 24 and 25. The first solar cycle documented by scientist began in March 1755.



The sun exhibits great variability in the strength of each solar cycle. Some solar cycles produce a high number of sunspots. Other solar cycles produce low numbers. When a group of cycles occur together with high number of sunspots, this is referred to as a solar Grand Maxima. When a group of cycles occur with minimal sunspots, this is referred to as a solar Grand Minima. Usoskin details the reconstruction of solar activity during the Holocene period from 10,000 B.C. to the present.8 Refer to Figure 2. The red areas on the graph denote energetic solar Grand Maxima states. The blue areas denote quiet solar Grand Minima states.

The reconstructions indicate that the overall level of solar activity observed in the middle of the 20th century stands amongst the highest of the past 10,000 years. The 20th century produced a very strong solar Grand Maxima. Typically these Grand Maxima’s are short-lived lasting in the order of 50 years. The reconstruction also reveals Grand Minima epochs of suppressed activity, of varying durations have occurred repeatedly over that time span. A solar Grand Minima is defined as a period when the (smoothed) sunspot number is less than 15 during at least two consecutive decades. The sun spends about 17 percent of the time in a Grand Minima state. Examples of recent extremely quiet solar Grand Minima are the Maunder Minimum (about 1645-1715 A.D.) and Spörer Minimum (about 1420-1570 A.D.)



The sun has been undergoing a state change. It transitioned from a Grand Solar Maxima, which typified the 20th century to a magnetically quiet solar period similar to a Dalton Minimum.


III. Detailed Forecast

I predict that the intensity of Solar Cycle 25 will be fairly similar to Solar Cycle 24. I base this prediction on two observations:

1. The pattern seen in Solar Cycles 22 through 25 matches fairly close to the historical pattern seen in Solar Cycles 3 through 6. Refer to Figure 3. Solar Cycle 4 to Solar Cycle 7 corresponded to a period known as the Dalton Minimum. The Dalton Minimum was a time of minimal sunspots, a series of weak solar cycles; but it is not weak enough to be described as a Solar Grand Minima.

2. Solar cycles come in pairs. A solar cycle is in reality a half cycle. It takes two solar cycles to complete one full cycle. In one solar cycle, the magnetic polarity of the sun faces north and in the next it faces south. At the end of 2 solar cycles the sun is back to its original starting point. So they are two different sides of the same coin. The intensity of each half cycle is approximately equal.

In my opinion, the most interesting part of the upcoming solar cycle is the period of minimal sunspots⊕ rather than the period of maximum sunspots because the minimum represents the extreme, the primary actor that foreshadows weather events. When I compared this upcoming period of minimal sunspots with the corresponding period of minimal sunspots during the Dalton Minimum (between solar cycle 5 and 6), I made the following predictive observation. The upcoming period of minimal sunspots will extend from the winter of 2016/17 to the winter of 2024/25. This period is analogous to the similar Dalton Minimum timeframe from the winter of 1806/07 to the winter of 1814/15.

I predict this upcoming period of minimal sunspots shall be longer and deeper than the last one. The changes during this solar minimum shall be more pronounced than during the last solar minimum. These parameters include sunspot numbers, Average Magnetic Planetary Index (Ap index), Galactic Cosmic Rays (GCRs) flux rates, heliosphere volume, the sun’s interplanetary magnetic field strength, solar wind pressure, solar Ultra Violet (UV) flux rate, Earth’s thermosphere volume, solar radio flux per unit frequency at a wavelength of 10.7 cm, and the latitude of Noctilucent Clouds (NLC) sightings.


The Report goes on to discuss possible weather effects, and some of the theory behind solar minima affect global climate and extreme weather events during the Dalton minimum.

  1. February 11, 2018 7:18 pm


    Heartless, cruel….

    I am struggling with this…

    What did he expect?

    A few polar bear hugs next up then?

  2. HotScot permalink
    February 11, 2018 9:44 pm


    My wholly uneducated opinion is, that predicting solar cycle effects on the human race is as futile as anticipating climate change effects on the human race.

    I have no doubt we can learn some lessons from solar activity, but scientific obsession with the subject threatens to turn the gullible public back a few thousand years rendering them sun worshippers.

    The sun may become the new climate change disease to affect the pessimistic plebs, of which, I count myself one, except I’m an optimistic pleb.

    The expression ‘we need another war’ as distasteful as it seems, distracts the human race from self obsession.

    We are currently self obsessed about a future beyond our historic projections which were almost day to day.

    I guess climate change is our intellectual battleground now the planet is as peaceful as it has ever been.

    • jim permalink
      February 12, 2018 3:08 am

      HotScot, I think its something to do with the ‘precautionary principle’ gone mad. Our western societies have become obsessed by risk averseness , and part of this is the neurotic need to ‘know’ what is going to happen before it does, so we can plan for it. Its a sign of madness afflicting a good proportion of the human race. Computer modelling is on the cusp of changing human perceptions and not in a good way.

      • Gerry, England permalink
        February 12, 2018 1:57 pm

        As with computer modelling, artificial intelligence is draining away human intelligence and if allowed to expand unchecked could see retardation of the human race. Some say that it has started already in parliament…. Joking apart, perhaps meteorology shows what this can do already relying on models and not judgement, which might explain the declining accuracy of forecasts.

  3. dave permalink
    February 12, 2018 9:36 am

    ‘”…the ‘precautionary principle’…”

    As satirized, long ago, by ‘Lewis Carroll:’

    His ‘White Knight’ put iron anklets on his horse “to stop the sharks from biting.” He would have been better off learning to ride, as Alice tactlessly pointed out when he crashed to the ground for the umpteenth time.

    This was in “Alice Through the Looking Glass” and, of course, in that book, the professional student of logic, Dodgson, was essentially writing about things that people got “backwards.”

    Meanwhile the quantity of sea ice in the Arctic is growing “healthily” this winter. The extent is down a little, but the central area compensates with thickness.

  4. February 12, 2018 2:16 pm

    This is “Our Mister Sun” at work or at rest. It is not President Donald John Trump pulling us out of the Paris Climate Accord. Neither is it Michael Mann’s Hockey Stick Curve based upon the removal of the Medieval Warming or the Little Ice Age from history. No, it is still “Our Mister Sun.”

  5. February 12, 2018 8:43 pm

    In solar cycles 15-23 (1913-2008) only one cycle was longer than 10.5 years, against an expected average of just over 11 years, and the number of sunspot-free days was generally in decline.

    Now we’re getting the other side of the coin, for how long no-one knows but it could well be long enough to put a drag on global temperatures.

  6. February 13, 2018 2:45 am

    Reblogged this on WeatherAction News.

  7. Colin Brooks permalink
    February 13, 2018 3:23 pm

    The scientists who study solar cycles have been predicting a deep solar minimum for many years and I am sure that it will happen in the next year or two. What I do not like in this report is the idea that somebody was able to ‘reconstruct’ solar cycles back for 10,000 years with no explanation as to how this was done.

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