My last post about the Sun is from August 2010. At that time it had become clear already that the present Solar Cycle 24 would be a weak one. We are now two years further, the maximum in solar activity is expected around September next year. Time for an update.

Here is the most recent prediction, with data points until September

The current prediction is a (smoothed) sunspot number maximum of about 76. That is low! We have to go back to Cycle 14 in 1906, to find a lower maximum value of 64.

Here is a graph of the Solar Cycles over the past four centuries. With red crosses I have marked the 1906 maximum and the (predicted) 2013 maximum.

You will notice that the last half century we have had a “wave” of solar activity. Is that coming to an end now and will we enter a period of low solar activity? Nobody knows, as we do not understand very well the origin of the Solar Cycle.

Both the Maunder minimum (17th century) and the Dalton minimum (~ 1800) had influence on the Earth climate. Severe winters in Europe as can be seen in paintings of the Dutch School, like this famous one by Hendrick Avercamp (1585-1634)

Now we live in a period of global warming. There are strong indications that our carbon emission is at least partly responsible for this. But could there also be a contribution due to the high solar activity during the last fifty years? Those are sensitive questions..:-)