During the past several years, the Chandler Wobble has been intensifying at an increasing rate, making the wobble more elliptical in nature. This could be caused by a change in the rotation of Earth's core relative to the outer crust. These kinds of changes leave an enormous impact on the planet, such as an increase in the intensity of earthquakes and volcanism, the more violent and longer lasting El Ninos that we have experienced and other weather related phenomena. Further, it very well may be that the current extreme Chandler Wobble may be a precursor to a pole shift.
Magnetic pole shifts are the most studied and documented of pole shifts. Scientifically we know that there have been thousands of such shifts. In some cases Earth's magnetic poles have shifted as much as 180 degrees, a complete reversal. When this happens, your magnet would point in the opposite direction from where it was originally pointed.
The Sun just recently in the past few years has experienced a magnetic pole shift. In this case the Sun's north magnetic pole became south and south became north. Earth's geomagnetic pole shifts have not always been a complete reversal. They have moved anywhere from a few degrees to 180 degrees.