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It’s time for my monthly sunspot update. On Sunday NOAA posted its monthly update of the solar cycle, covering sunspot activity for February 2018. Below the fold is my annotated version of that graph.
Sunspot activity in February continued the low activity seen in November, December, and January, with November 2017 still the most inactive month for sunspots since the middle of 2009. In fact, the low activity we are seeing now is somewhat comparable to the low activity seen during the ramp down to solar minimum in the first half of 2008. By the end of that year we had hit solar minimum, the deepest and longest in a hundred years, suggesting that we might even hit solar minimum before the end of this year. That would have this happen at least a year earlier than all predictions.
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.
Overall, this solar cycle appears to be the weakest in more than a century. As noted at this link, “most scientists currently alive have never seen such a weak cycle.” The article at the link outlines the numerous indicators that support this, outside of sunspots, including radio flux, proton events, flares, and geomagnetic disturbances.
A look at the graph above shows this as well. The red and green lines show the predictions of the solar science community. Actual activity has never come close to matching any of these predictions. The ramp up started later then every prediction, never got as active as any prediction predicted, and started ramp down sooner than expected. Right now, if solar minimum happens in 2018, this solar cycle will only be ten years long, one of the shortest solar cycles on record.
Historically, all past short solar cycles were also very active solar cycles, so having a short but weak cycle would also be unprecedented.
None of this might happen. As I noted in my update last month, a close look at the previous ramp down in 2007 and 2008 shows that when activity became this weak, the ramp down slows. It could be that the Sun will remain in this wimpy state for at least another year before sunspot activity ceases.
Regardless, the low sunspot activity at this time continues to suggest that the next maximum will also be weak, and might even not come at all, as some solar scientists have proposed. Instead, we might be heading toward another Grand Minimum, with no significant sunspots for decades.
Will that Grand Minimum produce cold weather worldwide, as it appears to have happened during the last Grand Minimum in the 1600s? At present scientists do not have a clear link between that lack of sunspot activity and the cold weather that dominated the climate at that time, creating what some scientists dub the Little Ice Age. One link might be cosmic rays. During minimum more cosmic rays hit the upper atmosphere, and research at CERN has suggested that the cosmic rays can interact with atmospheric water and produce more clouds, thus cooling the planet.
This remains unproven however. More important, we have never had the opportunity to study the Sun with our modern satellite instrumentation during a Grand Minimum. The knowledge we could gain will be priceless in helping reduce the vast uncertainties that presently dominate the solar, climate, and astronomical fields.