Last Days on Earth Series Overview: 7 Deadliest Threats to Mankind

"Last Days On Earth" first aired on 20/20 on ABC and the History channel in 2006. Most episodes are also available on YouTube. The show reviews several possible causes of human extinction. Experts including Stephen Hawking provide commentary. The scenarios are ranked from least to most likely. They are:

Death By Star- either by gamma ray burst or black hole. Gamma rays travel at the speed of light so there would not be any warning. We see on average one gamma ray burst per day but doesn't affect us. A big one would destroy the ozone layer. Temperatures would rise and everything would be destroyed as cells would no longer be able to rejuvenate. Black hole- we used to think they were stationary but now we know there are thousands of black holes moving throughout the galaxy.
Intelligent Machines- I hope this is jus sci fi like "Terminator".
Supervolcanos- Yellow Stone National Park sits on top of a supervolcano which is overdue to erupt. We would only have a few minutes notice of such an event. Earthquakes would also occur as a result. This would be a catastrophic event for the US since 2/3 of the country would be covered in ash.
Asteroids- 99% of all creatures that ever walked the earth are now extinct. 65 million years ago an asteroid crash caused the extinction of dinosaurs. This enabled a small shrew type mammal to evolve eventually into us. There are lots of asteroids. Some 100,000 have been logged. Most thankfully pass us by. However there is an asteroid that is on course to travel between our communication satellites and earth on 4/13/2029. On its next orbit on 4/13/2036 it may indeed hit the earth. Scientist think that if they had enough prior notice the could use a ship to nudge asteroids into a new orbit in order to miss the earth.
Nuclear War- What to say about this that hasn't already been said? We have enough nuclear weapons to kill 8 billion people and there are only 6 billion people in the world.
Plague- This is listed as the number 2 threat to humans. This could be either naturally occurring or manmade. Thanks to air travel plagues can travel much more quickly around the world than previously. They have been some 100 plague events within the last 300 years.
Climate Change (Global Warming)- This is listed as the number one threat to humans. Spring now occurs two weeks earlier. The water level in the world has risen ~8 inches worldwide.

Grade: 4/12 Monsters (out of 5). A very interesting and thought provoking show. I would highly recommend it to anyone who is interested in end of the world scenarios.