I can remember if Civilization 3, if you fired too many nuclear weapons, then a warning sign would pop up letting you know that global warming would start (I don't recall this in Civilization 4?), and if you continued, you would gradually see the terrain change from lush to desert.
I had a go at using lots of nukes in Civilization 5, just as an experiment, yet I haven't noticed any global warming happing, or warnings about it.
I'd like to see such effects if a player was to decide to use lots of nuclear weapons, or a nuclear war was to start, global warming effecting the terrain, either turning the land into a wasteland, or a nuclear winter, if it gets really serious. Early on, after a few nukes have exploded, the player should get at least one warning, so a player who wants to use nuclear weapons, but doesn't want to change the environment, would know when to stop. Also, a lot of people like the Post-Apocalyptic genre, so if the world's environment was to change into the classical wasteland of a Post-Apocalyptic setting, some people might find this aspect very appealing (I know I certainly would). This leads to another possibility...choosing the starting map to be a Post-Apocalyptic landscape! (Then you wouldn't have to go as far as nuking the place to get the map looking the way you want it to) So most of the landscape would be wasteland and desert, with some oasis here and there, and destroyed cities left in ruins, and of course lots of radiation. They could also add a similar map for a Nuclear winter.
Would these be good ideas for the game, to add a bit more realism and variety, or would it just be unnecessary and overly difficult to incorporate into the game?