Magneto’s ability to manipulate electromagnetic energies is not merely limited to magnetism and electricity. He has also shown control over most of the electromagnetic spectrum. The electromagnetic spectrum is the collection of various radiations that stem from EM energy, having properties of both electricity and magnetism in motion, specifically in varying frequencies of oscillation, or size and speed of waves. These energies are: radio waves, microwaves, terahertz radiation, infrared, visible light, ultraviolet, x-rays, and gamma rays. Ergo Magneto can generate or manipulate radio signals, generate heat (Uncanny X-Men #104), sense heat signatures, manipulate light to make himself invisible (Vision and the Scarlet Witch miniseires Vol. 1 #4), use UV energy to break chemical bonds (though he usually used his own power over the magnetic fields within atoms to do so), and reflect the x-rays and gamma rays produced by nuclear explosions (X-Men Vol. 2 #1, X-Men Vol 2 #86).
Magneto should also be able deflect the solar winds (perhaps a variant of Marvel’s nebulous “cosmic energy”) as the Earth’s own magnetosphere does. He should be able to shape the northern/southern lights, which is the solar wind reflecting off the atmosphere at the poles (a rather romantic image). Because the solar winds travel along magnetic clines of force, it is theoretically possible for Magneto to shape and focus that energy and matter into something more damaging. However, contrary to popular belief (and the premise set forth by Morrison in Planet X) flipping the magnetic poles is unlikely to have a catastrophic effect on the world. The Earth has already gone through several such pole reversals without any major extinction events coinciding with them and we are already in the beginning stages of pole reversal now. The process of pole reversal is so slow, it is unlikely even our technology would even be affected.