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redrumloa said:
There are several poles that we could talk about and it's important we make sure we are talking about the right one in a given situation.
There is the pole that we have due to our axis of rotation, the pole we have due to the earth's magnetic field and the bits of the earth that are geographically at those points.
The axis of rotation wanders on a largely predictable basis because to a large degree we can consider the earth a solid body and classical physics applies. The axis of rotation precesses and so the whole planet wobbles a little.
The sea floor of the arctic and the continent of Antarctica are both moving over the mantle of the earth as are all the plates and continents. The process is slow. What is at the poles will one day be different and that will have a great deal of effect on the weather. If Antarctica was not at the southern pole there would be no place for winter ice to collect and so it would break up each spring (without land to shelter it). This would result in more antarctic ocean heating in the southern summers as the albedo or reflectivity of the ocean is less than that of ice or snow. In the north the arctic ocean is able to maintain sea ice because it is enclosed by North America and Eurasia which holds the ice in place during the summer. Changes in what bit of the earth's surface is at the poles plays a considerable role in global climate.
Finally the magnetic pole shifts and changes strength largely unpredictably because as far as we currently can tell it is created by dynamic and chaotic processes in the core. These systems cannot be accurately predicted though they often show some periodicity. The earths magnetic pole wanders around quite a lot and there are many local variations in field strength and angle. Fairly frequently, on geological timescales, this field will fade and then reestablish itself with an opposite polarity. The earth is not alone in this sort of behaviour. The sun has a magnetic field too and it's field polarity waxes and wanes then waxes again in the opposite polarity roughly every eleven years. One of the symptoms of this process is the number of sunspots on the sun's face over time.
The earth's field, according to some, is behaving in a way that would suggest a reversal is coming. Nobody really knows if this is so or how long a reversal should or could take but it is extremely unlikely that it would be on a timescale of just a few years.
In terms of catastrophes, the planet, as far as we know, has never ever flipped nor is there any plausible way that it could. Nor have has the crust moved in unison nor on short timescales of hundreds, nor even thousands of years to put the north continents in the south and vice versa. Magnetic pole reversal do happen and are recorded in the rocks. Not much terrible is expected to happen from this. Reversal are frequent and don't seem to coincide with dramatic events such as extinctions. Potential problems are with increased erosion of the atmosphere during during the reversal as more solar wind will reach to top of the atmosphere. It's not a very big effect and we won't all suffocate or anything. Solar storms may or may not have much effect on us since a large part of the electrical problems we experience are due to the interaction of solar ejecta and the Earth's field.
Magnetic reversals happen and look to be no big deal. Total planetary flips would be a big deal but never happen (unless we get hit by something the size of the moon, but then we have worse problems to deal with ... for a very short time).
ython:
