[jester]

Here is one:

One of the major religions finds their ancient lost ICON, and poof they go on the warpath.

Resources are always good.

Here is one, Oil runs out in the big players in the Middle East leaving only the smaller states with limited capacity. They unit with some of the larger super powers taking up sides. Kind of like WWI with all of the PACTs that were made.

I can see the three main players:

US
Rusia
China
India

Everyone else picks a side to join.

Then, we decide what countries still have oil.

Dubai, Kuwait <much reduced capacity> Venezuella, Indonesia, Gulf of Mexico, North Sea, Romania. Canada perfects the shale and sand oil production as well as the whole arctic oil gets going and Alaska is producing. Also, off the Coast of Africa, Fla and California. This way we can have forces fighting basicaly all over the world. Of course the main producers will still produce oil, but at just enough capacity to give them a reduced military vehicle capacity.


Another one is,

WATER!!!!! Some waterborne virus contaminates a good portion of the fresh water in the world. With only a few sites untainted. and a few plants able to purify contaminated water.


As for troops of a nation on the otherside of the world:

Releif personel. Been all over doing that work. Its easy and difficult, because you go UNARMED alot of the time. So, that could put a whole new dynamic to your PCs. Say they have a half a dozen weapons for an entire platoon, then the fit hits the shan in a royal way and they are stranded having to survive the masses of refugees, bandits who would prey on them religious fanatics, and those who would blame your characters nation for interfering or not helping enough.


Another scenario:

The earths rotation changes taking it about 3 to 4 degrees off, so when it gets cold it get colder to the point of just short of not allowing life to survive, but only for about a month to 45 days, and then when it returns it is that much closer to the sun having the oposite effect making that much hotter.


Or, the poles melt <I do not prescribe to the global warming theory personaly> but, with the above scenario it would work too. Flooding of coastal communities <where about 2/3 of the earths population lives> which in turn create a shift in the ocean currents which regulate weather patterns so now the weather is messed up and we then return to an ice age which again screws things up before the earth returns to stasis. That would be a good adventure for characters to work with.

Have them all start out with Red Cross and other releif workers supported by military personel <your PCs> doing rescue/releif work for some hurricain or tsunami ravages area.