Sunspots 2014: Case for a weak Dalton Minimum

Solar flares may decrease for 20 years or more. Credit/

Austin, September 2, 2014 – New evidence is accumulating each month during Cycle 24’s sunspot progression. The emerging picture shows that the sun is entering into a weak Dalton Minimum.

What is this evidence? What does it mean? How might it affect climate change here on earth?

The progression of this solar cycle is revealing tantalizing new clues with each month’s release of new sunspot numbers. Take those clues, combine them with what is already known, couple that with the historical record and the case for a weak Dalton looks strong.

Cycle 24 sunspot progression

New solar maximum set. Credit/SILSO data, Royal Observatory of Belgium, Brussels

The Royal Observatory of Belgium released the August monthly international sunspot numbers on September 1, 2014. Cycle 24 remains the weakest solar cycle in 100 years but another new solar maximum was set again for the seventh month in a row! In all likelihood, another solar max will be set again this month, but it is still far short of NASA’s prediction.

Ironically, as explained below, the unexpected rise in late cycle solar activity further bolsters the case that the sun is falling into a Dalton-like minimum.

Cycle 24’s latest smoothed solar maximum went up from 77.3 spots/day to 78.4 spots/day, inching ever closer to 80. NASA forecast a peak of 90.

Cycle 14 or Cycle 12?

Cycle 14 (1907) compared to Cycle 24. Credit/SILSO data, Royal Observatory of Belgium, Brussels

Until now, most solar physicists have compared Cycle 24’s progression to Cycle 14. That one peaked in 1907. Cycle 14 at maximum activity had a rather unique series of about five similar magnitude sunspot peaks looking like a case of mumps spread over four years.

Cycle 24 roughly matched Cycle 14 for the first 56 months after solar minimum. As Cycle 24 has progressed since then, it no longer matches. Cycle 24 took off while Cycle 14 did not.

In the entire 400-year history of sunspots, it’s rare for a secondary peak, like today’s cycle, to be bigger than the first. Its closest match now is to Cycle 12 that peaked in 1883.

Cycle 12 (1883) compared to Cycle 24. Credit/SILSO data, Royal Observatory of Belgium, Brussels

Cycle 12 was the lead-in to a series of five weak sunspot cycles in the late 19th and early 20th centuries.

These two cycles are practically twins:

  • Both are exceptionally weak
  • Both have singlet secondary peaks higher than their first
  • Cycle 12 occurred at the beginning of a series of weak cycles
  • Cycle 24 appears similarly positioned to Cycle 12

It’s noteworthy that Cycle 12 has the highest reliably determined peak-to-peak secondary maximum in the sunspot record. Cycle 24 is close behind in second place but may surpass Cycle 12 in the next couple months.

It’s also noteworthy that Cycle 12 had the longest following extended solar minimum of any in the entire official historical record.

The Dalton connection

Dalton Minimum entry. Credit/SILSO data, Royal Observatory of Belgium, Brussels

This graph plots the three cycles leading into the Dalton Minimum (in blue), overlaid with the most recent three cycles (in red). The display is current through August 2014. Both sets of three cycles share several curious similarities:

  • They have two straight declining cycles
  • The middle cycles have extended trailing minimums
  • The third cycles have secondary peaks higher than their first
  • The third cycles are exceptionally weak

Following the third cycle entering into the Dalton there was an extended period of nearly two years that the monthly sunspot number remained stuck at zero. That’s the longest time of zero monthly sunspots since 1749.

Extended minimums both preceded and followed the weak double-peaked third cycle of the Dalton. It’s probably related to the internal workings of the solar dynamo, as is the higher second peak. Unfortunately, solar physics hasn’t progressed to the point of being able to fully explain and predict these phenomena.


This month’s sunspot numbers are in. Another new solar maximum record was set. Ironically, it strengthens the case that the sun is headed into some sort of minimum activity phase.

Cycle 24, including this late cycle burst of solar activity, continues to mimic the conditions leading into the Dalton Minimum and/or into a set of five weak cycles in the late 19th and early 20th centuries.

Things today aren’t exactly the same as the three cycles leading into the Dalton. The second lead-in cycle started later and its extended minimum is a lot shorter than its Dalton counterparts.

Compared to its lead-in cycles, the third this time around is stronger than the ones leading into the Dalton. Cycle 24 is more closely related to Cycle 12, which itself was the lead-in into a series of five weak cycles overlapping earth’s modern temperature profile. That profile serves as the basis for all global warming theory. Back then earth was about .9° C cooler than today.

Just yesterday, September 1st, a new paper establishing a statistical sunspot and earth temperature link was published in Physica A: Statistical Mechanics and its Applications. A rebuttal also appeared in the same journal. The sunspot/temperature link remains a hotly debated topic.

Over the last 400 years the minimums of the Maunder, Dalton and late 1800s/early 1900s have all been tied to cooler earth temperatures.

Cycle 24 shares similar characteristics to both the Dalton and the weak cycles leading into the modern era. Perhaps the sun is returning to conditions similar to the late-1800s.

Right now, sunspots are becoming weaker and harder to see. It’s been known since the late 1990s that sunspot magnetic field strengths – the engine behind the spots – have decreased by a third. Their umbral intensity (darkness compared to surroundings) has decreased by a third as well.

Sum everything together as we know it today and it adds up to this: Earth’s sun is heading into a weak Dalton-like minimum over the next several cycles.


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