Interesting story, but a bit on the brief side. I would have liked to see a third scene, perhaps Hermione freaking out over humanitarian aspects in a debate with Ron or another pureblood over the nuclear strikes as opposed to a short paragraph at the end. You could have had Harry simply sitting and conducting the movements of the flames in the fireplace while the two lamented and argued over the current situation; at least I think that it would have been more powerful than just outright stating what happened in the end.
Regardless, pretty original idea and decent execution.