Ashlee Simpson?
In another thread Eve stated she was lazy. My opinion of this thread is that she is working too hard. 
[sup]Chill out, Eve[/sup]
May I turn the question around a little, and talk about stuff we’ve already got?
I think it would be funny to be invaded by an alien race so advanced that they can see and hear in a much greater portion of the electromagnetic spectrum than we can, encompassing, say, the part we use for AM radio and the Home Shopping Network. After a few days of constant nonsensical hallucinations reduce the expeditionary force to near-insanity, the invaders decide to flee, only to have their ships crash under the weight of all the cubic zirconia, NASCAR memorabilia and Popeil Kitchen Magicians they were irresistably compelled to buy.
Alternatively, we could be menaced by sophisticated but slightly nearsighted aliens who abandoned their own world to escape a fearsome predator, a venomous and ravenous beast massing about 100 lbs., green, with a broad brown stripe. Deciding our little planet is ripe for conquest, their armada descends upon Washington, D.C.
Just in time for the international Girl Scout Jamboree.
Come on, any planet that has water-borne animals which swim up your pee stream right into your peehole :eek: aren’t worth invading. Where would an alien take a leak? Its not safe anywhere!
Also, look at the hordes of microorganisms teeming all over the globe. Not even the inhabitants are immune to fatal diseases. If the critters hanging out in human feces are potent enough to make the humans ill/die, just think what they could do to some foreign species? :eek:
How funny you should mention that, I always imagine what would happen if there were still large predators around, like sabertooths or something.
Or perhaps something like of the creatures that came out of King’s “The Fog” (or was it the MIST?).
Wouldn’t that be creepy? You get to work and find out that yet another several city dweller were eaten or mauled by the giant cats prowling the world preying on we weaker slower humans.
Acid lakes. We have them…but it’d suck if we had like millions of them, everywhere.
Our sun could be a blue-white star, bathing the surface of it’s planets with massive amounts of ultraviolet radiation.
Natural “nuclear reactors” might be commonplace.
One word: Sauropods.
One phrase: global bilharzia.
It could rain hydrocarbons, which could be easily ignited by lightning.
Dihydrogen monoxide everywhere. That stuff can be lethal, even in small quantities.
We could have developed into one of those species where the female kills then eats the male after sex so as to provide sustenance to the upcoming fetus. And then the baby eats its way out of the mother. Boy, what crazy religions would we have then!
What if some strange virus developed that when you got it kept you in puberty forever. A whole world full of hormonally charged people.
On a more fun note we could all be cast under a spell whereupon touching another person means you switch body types with them. What a wild and crazy game of tag that would turn into.
Eve, check out “Something Passed By” by Robert McCammon. It’s a short story in a collection entitled “Blue World”. Something passes near Earth and scrambles cause and effect at (apparently) a molecular level. Gravity becomes random (sudden crushing increases he calls “gravity-howitzers”, followed by sudden decreases which occasionally hurl someone off the planet), Water becomes poisonous, etc.; Essentially all the former rules no longer apply. I thought it was a great story.
Enjoy.
How about an alien species that considers its young as vermin or prey? They are spawned in the thousands, but they don’t become self-aware and intelligent until they reach the adult stage. Adults and larger young will snack on the smaller ones until the fittest survive to perpetuate the species, an act about as common as defecating. They ask how our young taste?
My favorite has always been that frozen water still falls from the sky like it does now, but a years’ worth falls all at once.
Picture it: With a gigantic THUMP!!!, a 3-foot thick layer of ice falls at a hundred mph onto an area the size of Ohio, crushing everything not underground. In wetter areas, make that 6 or 10 feet of ice.
The Weather Channel would be watched a LOT more attentively for signs of Doom.
OR
If strong earthquakes were as common as strong wind or heavy rain, we’d have a hard time building anything. Every 3 weeks or so anything not built super-solid would be shaken to bits.
Or what if earthquakes weren’t very severe but instead they lasted for hours, with the effect that standing on the ground felt like floating in a lake in a small boat on a windy day. Continuous motion, mostly not enough to knock you over, but standing upright takes constant effort.
That’d sure mess with aliens used to solid ground.
If there really were things that go bump in the night. Things that live in darkness, can’t be detected, and do unimaginable things.
Nobody would be able to go out in the darkness.
This is why the space aliens keep nabbing people and jamming probes up their butts.
They’re thinking “These people evolved in this hellhole? They must be BADASS.” and they’re trying to figure out just what makes us so tough.
We’re the most dangerous things on a dangerous planet.
Regular earthquakes that cause destruction. You just KNOW they’re going to start happening. And once the big one in San Francisco hits, it will trip a period of tectonic activity like nothing we’ve ever seen before. Then, you’ll just be anklin’ down the road and rrrrrrrrriiiipppppp!!! the ground opens up and swallows a car or a quickie mart or something, and you just go, “Hmmmmmm…” and move to the other side of the street.
Yeah, whatever.
Solid clouds.
Foggy days would be very inconvenient.
Well, some of the things mentioned here don’t fall under the “about natural phenomena that might occur on Earth, but don’t” category because they can’t happen, period. Fer instance, gravity is not a force, but a product of the warping of spacetime by objects that possess mass. Thus, you can’t “turn off” gravity any more than you can turn off space itself. Ditto for giant insects–the surface area to volume ratio decreases, so oxygen can’t diffuse through the insect’s breathing spiracles, plus the increased size of the body with skinny insect legs would ensure that it would be unable to move.
Now as for unpleasant scenarios that humans could survive, some are already in process. Take global warming. Over the next century, we’re going to see the loss of coastal areas aroubd the world due to rising oceans–say goodbye to New Orleans, New York City, and Miami. We’re going to see a serious increase in the number and intensity of storms, plus we’ll see crop failures and fresh water shortages in much of the world.
For more extreme scenarios that could happen that might not be survivable, check out the Exit Mundi site.
Party pooper.
How about if cats were not small but rather the size of cats in the wild? What if Tiger man was the norm? So if you forget to fill the dish you migh get eaten, that would be rather annoying.
How about if Killer Bees were actaully the threat they movies promised to be?
What if ‘natural disaster’ movies were documtries? Killer ants, rabid bears, flying pirhanas, were all just part of everyday life.
You can always one up on the diseases. No matter how bad the ones we have are, there’s always a worse one coming down the pike. A couple of my favorites from an old Onion article:
Spontaneous pan-corporeal organ rejection
Explosive urethral exsanguination