Digital Wanderer

I watched the ABC documentary "Last Days On Earth". It's about the 7 most probable ends of human civilization. The film is beautiful, though populist.

I'll list them in order of probability (roughly based on the film), with my commentary.
1) Astrophysical catastrophe: the explosion of our or a neighboring sun, a rogue black hole.
Unlikely, but beautiful.

2) Asteroid.
Slightly more probable, but there's a high chance of altering its orbit and surviving. This was covered in the film.

3) Artificial intelligence.
It's hard to estimate the probability, but personally I think it's high. The thing is, the number of transistors is approaching the number of neurons in the human brain, and so the "transition of quantity into quality" according to Prigogine might kick in, and with minimal effort from actual humans at that. We have 20-50 years left, no more.

4) Supervolcano eruption.
There is a special type of volcano that can spew out a massive amount of lava and ash. This will clog up the atmosphere, create a pseudo-nuclear winter and poison the water to the level of acid over a huge territory. One such eruption could wipe out the population of almost all of America.

5) Nuclear war.
For now, making a nuclear weapon isn't all that easy, but the task is gradually getting simpler. On one hand, the geopolitical atmosphere isn't great right now, on the other — totally sick regimes, even if they could do damage, would only hurt their neighbors. The only plausible scenario for a global catastrophe is a provocation staged by terrorists and the stupidity of one of the nuclear powers that takes the bait. Russia is in a bad spot here: security is poor, stuff can be blown up or stolen.

6) Bacteriological threat.
Everyone's heard of bird flu. Well — there are lots of diseases like that. The threat is also growing thanks to the widespread use of antibiotics and the active fight against diseases. The better we fight, the harder they hit back.
There have been many pandemics, and bacteria, and especially viruses, are the most perfect creatures on earth, with incredible abilities to adapt.
If you consider that the equipment to modify and enhance them is widely available, the threat multiplies manifold — soon a few tens of millions of dollars will be enough to get a deadly strain of some known disease. Creating an antidote takes several months — by that time everyone will already be dead.

7) Global warming.
The film presented an absolutely one-sided point of view. Global warming is a fact, and it's caused by humans. That's what all climatologists think, except for a few bought by TNCs.
If we don't do anything, most of the inhabited territory will soon be under water, terrifying tsunamis and tornadoes will begin, and we will all face a slow and unpleasant fucking end.
Looks plausible, good thing at least it won't be right now.

Every episode was commented on by scientists — specialists in their field. And they asked the most famous scientist on the planet to shed light on the whole thing — the astrophysicist Stephen Hawking (Hawking)
Hawking is a cult figure in the world of techno-freaks. He is a paralytic, confined to a wheelchair, and only able to blink. Under his directions, a system was created that allowed him not only to communicate with the outside world, but also to do scientific work. He wrote the books "A Brief History of Time" and "A Briefer History of Time", which became bestsellers.
His commentary in the film looked unrealistically cool and futuristic: a motionless man of the "mad scientist" type, and a computer-synthesized voice, the meaning of whose words is repeated on the screen with subtitles.
And the commentary was very short, extremely clear, and capturing the essence.

The leitmotif of the film is this: if we can't rein ourselves in, we'll go extinct. In the best case scenario, almost everyone, if not everyone.
And the practical advice is this: conserve electricity and the environment. Americans just can't help moralizing :-)

It's a pity the film didn't present one more scenario — witty, but hard for a layman to grasp. They could have told it, at least as part of the artificial intelligence episode.
This scenario is Vernor Vinge's singularity.