Threads
"Threads: A Grim Post-Nuclear War Roleplay"
Heavily based on the movie Threads' prediction for a nuclear conflict culminating into MAD and its post-war effects on society and global environment.
(obs. after nuclear detonations: a.f.d.)
In essence,
Period of extreme cold: decrease 20 C degrees on the common temperature range in a given location
In the first few weeks (0 - 4 weeks afd), there would be disorganization, injury-related deaths, and overwhelming radiation emanation that could kill anyone in a matter of hours;
In the next couple of weeks (4 - 36 weeks afd), the surviving governmental apparatus would attempt to regain control; radiation-related deaths would peak; raiding and a general survival of the fitness pillaging and murdering would ensue; and radiation exposure would be sufficient to kill someone in a range of months to years.
In the remaining months up to next year (4-5 months - 1 year afd), whatever is left of the State would have solidly regained what little control it can - mostly in specific regions of specific cities, controlling food depots, commencing agriculture (which would obviously be measly) - and those territoes would be somewhat organized; radiation-related deaths would begin to stabilize, most deaths now related to malnourishment/dehydration/murder; radiation exposure would probably take a few years to kill people.[/ol]
The following years (1 ~ 10 years afd), the State would have either succumbed due to poor harvests (and along it, any prospect of civilization), or it would have thrived with enough food to stabilize malnourishment deaths to the point rebuilding society would actually be possible, that would imply in some very rudimentary, NCR-like organization; with less injury/radiation/hunger-related deaths, diseases and cancer would be the prominent killers; most 'non-urban dwellers' (nomads, pillagers, prospectors, loners) would be experienced enough to survive in the harsh new reality, peaking the survival of the fittest mentality.
The sun finally shines: less cold, but without ozone, a lot more UV radiation, skin cancer and sunburn
The next decades (10 years - 30 years afd), the skies would finally be clearer.
The rest of the century (30 - 100 years afd) is mostly speculation. The main difference is that most likely children born would no longer be starkly malformed, stillborn, mentally impaired, etc.
Notitia de Occasus:
Dignitas: