12 Ways the World Really Could End

A slide show at Popular Science of 12 environmental/natural disasters that could result in mass death. The 12 are:

1.  Asteroid impact.
2.  Pandemic.
3.  Machines take over.
4.  Gamma-ray burst.
5.  Snowball earth.
6.  Ocean acidification.
7.  Solar storm.
8.  Super volcano.
9.  Geomagnetic reversal.
10. Nuclear war.
11. Artificial black hole.
12. Something else, like vacuum decay or a collision of 'branes.