[fpoling]

This is poorly discussed in the article and AFAICS it reaches wrong conclusion.

I think the energy comes from weakening of the magnetic field and the energy stored within it, not from slowing down earth rotation. Earth as the result may rotate faster as the moment stored in the field will be transferred back to Earth as in the example with a sphere from the article.

[qnleigh]

That would make so much more sense. So then the comments about only slowing down Earth's rotation by a few ms/century. It would deplete Earth's magnetic field, and likely on a much faster timescale.

This would not be good...