>Now from a climate standpoint- large amounts very tiny particles do have a measurable effect on global warming. If we're burning up a mass of aluminum on the same order as all of the meteorites that enter the atmosphere, then the effect is probably negligible, however.

That's a good point to add to the discussion. Micrometeorites are believed to enter the Earth's atmosphere at a rate of many tons per year. One study estimates roughly 10^6 kilograms yearly

So the Earth has already long had massive amounts of metallic elements entering the atmosphere and vaporizing.