The sun’s magnetic field reverses roughly every 11 years at solar maximum. We are now approaching solar maximum of solar cycle 24 (SC 24) but this magnetic reversal is strongly assymetric according to NASA:
“The sun’s north pole has already changed sign, while the south pole is racing to catch up,” says Scherrer. Soon, however, both poles will be reversed, and the second half of Solar Max will be underway.”
The North pole of the sun switched polarity in mid-2012 which seemed early at the time since solar maximum was not expected till the fall of 2013. It is difficult to imagine that there will not be consequences for the Earth but what those consequences might be is not a “settled science”.
Certainly geomagnetic reversals on Earth have more to do with the flow patterns in the earth’s liquid core and have quite different time periods. The time span between geomagnetic reversals on the Earth vary between 0.1 and 1 million years with an average of 450,000 years.
The latest one, the Brunhes–Matuyama reversal, occurred 780,000 years ago. However,a study published in 2012 by a group from the German Research Center for Geosciences suggests that a brief complete reversal occurred only 41,000 years ago during the last glacial period. The reversal lasted only about 440 years with the actual change of polarity lasting around 250 years.
From Dr. Leif Svalgaard’s research page:
Solar magnetic reversal cycle
The NASA press release says:
August 5, 2013: Something big is about to happen on the sun. According to measurements from NASA-supported observatories, the sun’s vast magnetic field is about to flip.
“It looks like we’re no more than 3 to 4 months away from a complete field reversal,” says solar physicist Todd Hoeksema of Stanford University. “This change will have ripple effects throughout the solar system.”
The k2p blog 