- nucklear war
- astroids hitting earth
- climate change
- sun dies.
Some say the world will end in fire. Some say in ice.
War is the most likely.
Asteroid impact is unlikely…but scary because we can’t do anything about it.
Climate change is certain…but won’t end civilization.
The sun seems pretty stable, but you never know when Ol’ Sol might burp up a king hell flare. Like an asteroid impact, highly unlikely. And we can do something about it – harden all our electronics. (Also protects against weaponized EMP.) However, the world will take note of the price tag, and continue to “hope it doesn’t happen.” That’s humanity for ya!
I’ll go with the LHC turning all of us into a black hole.
The OP asked when the world- not civilization- would end. I think the planet will long outlive us, and eventually be swallowed up by the Sun.
Miscalculation by an FTL ship causes it to pass through the Earth, leaving behind nothing but a smoke ring.
All because the Vogons read the wrong chart.
I say "Garden Gnomes.
Garden Gnomes on FIRE!
The Sun will eventually grow into a red giant and consume the planet. Nuclear war, climate change and asteroids will at most cause a few scuff marks on the surface of the planet before then.
But note that long before the Earth is vaporized by the expanding sun, it will have become so hot that liquid water will no longer exist on the surface, even at the poles. At that point even extromophile prokaryotes will have a hard time existing.
Then the tardigrades will proliferate, eventually evolving to become the new Master Race.
In a bang . . . followed by a whole lot of whimpers.
This. That’s how the planet will end.
How the biosphere will end is somewhere upstream of there. As pointed out by Lemur866.
How humanity will end will be further upstream of where the biosphere ends. Arguably just on genetic drift alone the “humans” from 100,000 years from now will be more different from us than we are from Neaderthals. And hence won’t be “humans” at all as you and I understand the term. And that’s before you inject any deliberate genetic engineering into the scenario. Engineering that we’re on the cusp of starting today and which will probably be fairly widespread and routine in a mere 100 years.
Wikipedia has this covered.
According to Wiki, the Earth will only support multi-cellular life for another 800 million years. Lack of CO2 is going to be a big problem.
Grey Goo
Ghost grass.
George Bush Jr. becomes President of the United States.
From what I’ve tasted of desire I hold with those who favor fire.
In 2101 A.D. war will begin. Somebody will set up us the bomb, and we will be on our way to destruction.
I hold with those who favor fire.
(And damn you for the ninja, on the very first post!!! I’m not a huge poetry fan, but I could read RF all day long…)
With a “d”, just like always.