Even asteroids, super nova's, cosmic radiation, bigger but dumber predators (Dinosaurs), etc.. lots of external factors could destroy a planet too, a planet is a fragile place, and keeping life on it is a fragile balance, it's a miracle we've lasted so long, imho.
None of these things is likely to actually be the end of life altogether, just life as it's known at the time. More asteroids won't make the Earth completely uninhabitable (just as it didn't the first time); nor will climate change (just as it hasn't before: https://en.wikipedia.org/wiki/Great_Oxygenation_Event). They'll simply be the end of our current human civilization, along with plenty of other current species. Other forms of life may benefit tremendously; things will evolve to take advantage of the new circumstances.
Quite, but it may turn out to be a great filter that no species, alien or terrestrial, has yet got past. Thus there may no end of life out there but none that has advanced far enough to be noticed.
Perhaps we'll be the first, though I have to say I'm far more pessimistic than say a decade or two ago.
I'm hopeful we can develop immortality tech, if we can do that, then also build generational ships...even if it takes 10,000 years we could colonize every habitable solar system, even without light speed travel and send findings back to earth on discoveries found. Obviously having a working Albucierre (Sp?) drive or similar would make things better, or some sort of wormhole tech. But we can get to alpha centauri in 100 years, sailors used to risk their lives to go on voyages, why is it too much to ask the same of scientists and their families?
Esp if we can figure out cryostasis, we should definitely make a trip to Alpha Centauri with actual people someday, if there's no-place habitable they could just keep moving on till they find a place. In the off chance something bad happens on earth at least they'd be able to reboot/restart mankind on a new planet.
Imagine if 10 generational ships set off in 10 different directions headed to 10 different solar systems looking for a habitable planet to setup camps. Even if it takes 500 years for each to reach their destination, if longevity increases into the 1000's of years, we'd still be able to witness it and it'd be pretty cool.
Those things probably won't escape the atmosphere, however. It would be much harder to bootstrap an energy-hungry civilisation any time within the next few billion years, as we've used most of the easily-accessible sources of fossil fuels. If human civilisation falls, whatever comes afterwards probably wouldn't be able to build a rocket, unless they wait for fossil fuels to regenerate.
