In response to Out of the Mouths of Reporters:
Another thought about the "global warming attracts asteroids" nuttiness: Leftists understand that even patently absurd propaganda can be effective when it's wall-to-wall. Global warming (and later, when that term became too specific and untenable, "climate change") has been a flood-the-zone affair, since its inception. It's everywhere. It's difficult to get through a few days of nothing but light entertainment programming without being hit by global warming ideas and terminology, dropped casually by characters in everything from breezy comedies to sci-fi epics. And of course, it's perpetually appearing in news broadcasts, too. I vaguely recall a story years ago in which some meteorologist urged his peers to mention global warming at every opportunity, precisely because he understood the value of repetition, particularly casual mentions.