It seems odd to me that there isn't a (potentially hidden) countdown to Nuclear Winter that can be triggered. If this option, a severe weather event chain that every culture would have to respond to - but could respond to in their own way - might be a good test bed for other ecological or global events. Some possible triggers for the countdown could be; anyone player using nukes in a way that would trigger Mash The Red Button (or) Every Empire uses a nuke / does a nuke trial (or) a small chance anytime an Empire launches a max level Nuclear Device.

With that said it's also a bit disappointing that Wastelands don't have some special properties. Never being in supply (always damaging units on a Wasteland hex) seems a given. Additionally chances of unfortunate - assuming medical events can be flagged for these units - events are more likely to happen to units in a Wasteland. Moving into a wasteland hex on a tactical map should damage the unit at the end of the turn.

Finally it'd be very gratifying if you could eventually reuse the land - after being created areas could over time return to being bare grassland. You'd still need to bolster it with forests to be good. 

Lastly if there's a river or a lake in the detonation radius perhaps a one time jump in pollution could happen in that territory.

I do think the Nuclear winter can be represented through the pollution system. Though there's a non-zero chance that the best way to represent it, within the current systems, would be to have each Westland tile provide +50 pollution. As I don't think there's any simple way to represent weather... outside of the ocean tiles.

Yeah. I was thinking of an "Event." or maybe an Event Chain with mostly bad options. But yeah I understand the constraints. 

Currently too much pollution ends the game but yeah an event chain started once the global pollution levels rise could be more interesting.

*nods in mathematics*