I agree. It is quite possible that some loony running a country with nuclear power might just fire a nuclear weapon off, starting a really bad bad war. Or, some disease like ebola could cause massive death around the world. Most likely scenario is that humans will just keep polluting the earth until it just can't sustain life any more. How long? A few more generations of it and the world is doomed!
All I can do is vote, and contribute as little as possible to the pollution myself.
It is rather discouraging to see how fast the Islamic State nutsos have moved, one possible future is that religious extremists will get power over more and more of the world.