In the tradition of Kat's iLJs. (How this entry started is a long story, but I ended up with some random fun links, so I figured I should get more and make it a full blown list. w00t.)
1) An ozone layer is a
nice thing to have. Among other things, it is a secondary defense against solar winds. Um,
our ozone looks like a 15-year-old's tattered baby blanket.
2) Our
primary defense for those winds, the magnetic field, is due to
reverse direction. Meaning, uh oh, when those ions from the Sun come blasting through, we'll have no defense.
3) It's naturally time for the earth to get warmer. We're still gradually warming from the last
ice age.
4)
Global warming, accelerated by man. It really sucks for the
polar bears. And basically, the hotter temps get, the faster everything melts and the more CO2 is released, which speeds up the process even more--causing more droughts, destroyed habitats, wildfires etc. Whee!
5)
Bird Flu! Or SARS or West Nile virus, or
whatever new plague finds the way to be
massively contagious and actually becomes a worldwide
epidemic. It's going to happen, those
viruses are crafty little buggers.
6) Yeah, there's quite a few stray asteroid floating around. It's quite likely that one could be heading straight for us,
ready to impact. The good thing is, as long as we have enough notice,
we should be able to blow them to bits. The best use for our nukes, and most asteroids are only losely held together and would stand no chance. But some would be a bit trickier.
Comets too.
7) Yeah, the
Sun will expand and fry Earth completely, but most likely all humans will be dead by that point. If not, we'll go camp out on Saturn's moons if we haven't already moved on from earth. By that time, we should have enough technology to
bring an atmosphere and water with us. ^_^
8) That nasty
Energy Crisis. If we don't find some
new source of fuel, it could seriously threaten our lifestyle in endless ways. Which could also leave us more vulnerable to one of the issues above.
9) not even touching the individual natural disasters. Big earthquakes, huge tsunamis, super-volcanos, etc. Big things that affect a focused area. Course,
unless they happen all at once, humanity as a whole makes it through ok. (But if you're concerned, I was advised that the safest place to live in North American is the "geologically dead"
Canadian shield... as long as glaciers don't become an issue!)
10) Hm, why wait for nature to screw us over?
FIRE ZE MISSILES!!! P.S. For more optimism, check out
this site that combines almost all our potential dooms! woohoo!