So make it bad luck combined with malicious intent... smack the planet with a comet the size of oh say new york city... it can break up before it hits, but because it broke up and was going for an ocean impact already... no body cared... what they didn't know is someone was getting ready to nuke the snot of an ice cap somewhere, probably intent on wiping out some major power but not much else, but the two events happened too close together...