Colin said:
2300AD already features an alternate timeline. It postulates WWIII starting around 1995 or so. If I can, I would like to move away from the alternate reality and towards something possible, at least to the extent that it could could in our future. That was part of the appeal of 2300AD to me.
The trick is to make it plausible.
Fair enough. So, it seems you need to pick a date for a catastrophy that will allow all of us to be dead and unable to note when time catches up, while giving enough time for recovery.
I agree with Doc that accidents and single terrorist actions, or disasters with long prep time aren't going to trigger a major nuclear war -it has to be somthing that puts the varous powers in fear of their existance -and fearing the possibility that their deterrent will be destroyed if they wait; or that they have already been hit with overwhelming force and have only a retributive strike left.
The asteroid isn't bad at all. As to provoking a nuclear exchange, you'll want to read or recall Lucifer's hammer, which involves a strike by a cometary nucleus (lots of small hits) which results in a premptive strike by chna on the (then) soviet union, to forstall the soviets need to migrate south once the resultant impact winter sets in.
IIRC, the soviet launch on detection of the chinese attack (still the policy, BTW, and why misfires and contact errors are a big fear); the US has been similarly primed fr an attack, and launches on warning of the soviet launches -which are primarily aimed at china, but still have a limited counterstrike. BOOM !. Not a full scale exchange, but a biggish one. Another novel, I cant remember , supposed a solar flare blasting either the soviet union or the US, cutting off all communications and control. And then, according to protocol, the surviving deeper silos and subs fire when out of communications for a set period.
Its not hard to imagine some kind of event like that which would trigger that nowadays -nuke wise, the situation is closer to the 1960's than the late cold war -the soviets and Chinese still only have about 10% of the US strike capacity -so it's set for hair trigger response - as we could certainly knock out nearly all their sites if they wait for a detonation......smoke em if ya got em.
A major, sudden climactic change has the potential for everone to start thinking that the lifeboat won't have enough seats......and the smaller nuclear powers could quite feasably decide that with the big boys distracted, its time to sort out old grudges....Israel, Iran, India Pakistan, N. Korea; and probably others. Only one of them needs to panic.
And a brief warning of such a disaster (like an incoming impact)may do more harm than good, too, as politicians have time to make decisions, but not enough to talk or make
good decisions.
Interestingly, if Russia and china and china are most worried about each other, and the US, Europe may well do better than it would have in the cold war when the USSR and Warsaw pact has ample nukes to hit Europe and the USA - not the case now. Note that I'm assuming that the USA won't pull down the temple as it were, if it looks to be destroyed -at least as far as striking non enemies.