And now, as if we hadn't already identified enough things that might wipe out our species, we learn that astronomers have discovered a loaded gun pointed at our planet. Wolf-Rayet star 104 could go supernova at any time, and it's pointed straight at us. At only 8000 light years away, it could emit a gamma ray beam that would fry Earth's ozone layer. At that point you would need some pretty stout sunblock...I'm thinking SPF 200 or something. Say, a quarter inch layer of lead paint, like Queen Elizabeth I used to wear. Trouble is, all the little plants and critters in the forests and oceans don't have any sunblock. We might be eating canned beans for a long, long time.
How much time do we have left? Well, the astronomers say this thing might blow at any moment. Which, to an astronomer, means a few hundred thousand years. Better start stocking the pantry now.