"I’ve always thought that humans will begin modifying DNA and making cyborg-like modifications to the human body until we reach the point that the concept of human will be so diluted that we will have to call ourselves another way, leading to the extinction of humanity as we know it."
"Astronomical phenomenon like a rogue planet, or an asteroid."
"A bad-tempered, bureaucratic alien species of space engineers deciding to construct a hyperspace bypass through our solar system."
"We have very low genetic diversity compared to other mammals because of this bottleneck. Basically, we are all a little inbred. Plagues hit us a little harder than they would – very low chances of an immune or highly resistant population."
"A.I. And by “A.I.” I mean Auto Insurance."
"My fav is gamma ray burst. If one happens close enough to hit us, we probably wouldn’t even detect it. That means that at any moment, we can be flash fried into extinction with very likely no warning."
"If tech suddenly went awry there would still be plenty of people able to live in local farms. It would destroy our civilization but people would survive. The only thing that would truly send humans extinct is the earth becoming entirely uninhabitable for us and the food we eat, like an asteroid boiling our oceans or something like that."
"Polar ice cap melts, releases bacteria from 5 million years ago and it’s pissed."
"Over consumption of resources in general."
"The sun will eventually end it."
"Chicken overlords waging war on chik-fil-a and we get caught in the crossfire. Eventually the only thing left will be smoldering human bones and a lot of fried chicken, just as planned. Then the aliens will arrive and due to their love of fried chicken they will set up a human civilization to farm chickens for alien consumption.
Once the aliens tire of fried chicken and stop suppressing the violent chicken genes the chicken overlords will rise again and the destruction will begin anew."
"Time. Nothing lasts forever."
"I think nuclear war. The madman theory states that no sane person would launch a nuke due to the fact it would end the world, but I don’t think sane people end up in power, and I definitely don’t think someone in power would concede power as a result of a war without lobbing one final and world-ending “f@#k you”.
For example, if Hitler had nukes, there is no doubt he would’ve lobbed them all over the world before killing himself."
"Dogs. In the future, people won’t even have rights, dogs will have all the rights. And people will just be lowly servants for dogs. Then dogs will see a meteor flying to earth and think it’s a ball to catch and let it hit earth, game over."
"I think people really underestimate what it would take to actually completely exterminate our entire species. We already bounced back from a population collapse down to under 10,000 once, we could do so again. Nuclear war, ecological collapse, incurable disease; I highly doubt that any of them could kill everyone. Even if it’s just a few isolated pockets in the outback or the jungle that survive, that’s still not extinction.
Honestly, I think it would take a cosmic catastrophe (asteroid/comet impact, gamma ray burst, etc) to completely obliterate us and that assumes that it occurs soon enough that we don’t have viable populations outside of Earth."
"The end of the world as we know it? What do you think would push us to our own demise? All answers are excepted, but amusing answers are preferred!"