"In the event an asteroid stirkes the earth (highly unlikely) "
It's not only likely, it's a certainty, especially on a geological timescale.
The comet that passed us this past Halloween was only discovered weeks before. It was several times larger than the one that caused the Tunguska event, which is considered the largest impact in history. Let that one sink in.
For some more sobering check out the following, watch the following.
Joe Rogan Podcast with Randall Carlson and Graham Hancock on asteroid impacts and mass extinctions
Of course there's always supervolcanoes and such to worry about like Yellowstone.