The sunspot decline continues

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On Monday NOAA posted its monthly update of the solar cycle, showing the Sun’s sunspot activity in July. As I have done every month since 2010, I am posting it here, below the fold, with annotations to give it context.

Sunspot counts continue to decline at a rate faster than predicted or is usual during ramp down from solar maximum. Normally the ramp down is slow and steady. This time it has so far been more precipitous. While the 2009 prediction of the solar science community (indicated by the red curve) suggests minimum will occur sometime after 2020, the actual counts suggest it will occur much sooner.

July 2015 Solar Cycle graph

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

In addition, sunspot activity for this entire cycle since 2004 has been well below expected or predicted values. If the recently proposed double dynamo theory is correct and we are about to enter another Grand Minimum, with no sunspots for decades, do not be surprised if we also experience increasingly cold weather during that time period. As I have noted many times previously, the last grand minimum, the Maunder Minimum in the 1600s, corresponded with what has been dubbed the Little Ice Age, a period with crop failures and summers that never arrived.

Interestingly, this slowdown in solar activity during the last decade has once again corresponded with a drop in global temperatures. Well actually, not a drop but a complete pause in any global temperature rise since the late 1990s, a pause of almost two decades. Whether the pause will become a decline in temperatures or the warming will resume is probably the most important climate question facing climate science today. Not only do we not know how the slight changes in solar activity cause climate changes on Earth, we are not even sure how significant those changes are, having never experienced a Grand Minimum since the advent of the space age and the ability to measure solar output accurately.

If scientists can put aside politics and focus on gathering data, they might find out. Sadly, I am not hopeful, based on the level of corruption I see almost daily in the climate field.


  • Phill O

    The predictions for the lower sun spot rate was written in Sky and Telescope some time ago, well before this cycle. They also predicted that the next was going to be even lower. I am not sure but I thought is was comparing data from the sun spot index with data from the 107 cm band. Can anyone clarify this?

    “If scientists can put aside politics and focus on gathering data, they might find out. Sadly, I am not hopeful, based on the level of corruption I see almost daily in the climate field.” Maybe I am becoming more cynical with age or maybe my eyes have begun to open. I see it everywhere.

  • I wonder if you are aware of the identity of the science writer who wrote that article for S&T. The title of the article, which was the cover article for that particular issue, was “What’s wrong with our sun?” Take a guess.

  • Forget all predictions of solar activity more than one cycle in advance: – there is a dominant random component in the build-up of the magnetic field, driven by turbulence, that just cannot be known. (Also see for a fine summary in German.)

  • Very interesting. If this doesn’t fall into the category of the uncertainty of science, I don’t know what does.

    Nonetheless, I suspect that there is still a lot more we could learn about the Sun and its dynamo that would give us a better chance of untangling and predicting its behavior into the future. For example, Grand Minimums involve a significantly different dynamic than the normal 11-year cycle. The differences should allow a prediction, once we have learned more about them. Right now, however, we have never studied a Grand Minimum up close with good space age equipment. We simply don’t know why they happen or what causes them.

  • Predicted by Landscheidt in the 1980’s when he discovered the past correlation of solar system barycenter entering the solar disk to cooling climate in the past. Maunder and Dalton Minima both appear to have been a result of this phenomena. SC-24 and SC-5 (Dalton Minimum) in particular share similar geometries (planetary mass positions and their effect on location of solar system barycenter).

  • Rocco

    I guess, RZ.

    Sky & Telescope August 2009
    What’s Wrong with Our Sun?
    By Robert Zimmerman

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