Yes, I actually have ideas for how weather patterns have shifted because of Epic events that occur in my story. In fact - I fully plan on weather having an impact on the outcome of what this world will look like by the end of the story.
Also, I am a HUGE fan of Jared Diamond and his books. His ideas on specific triggers causing the collapse of societies is, I feel, reasonably useful in explaining how some societies meet their end. I don't think any writer should go without reading his books if they want a realistic story about societies.
However - a breakdown of the nations of Theron, starting with the northeast continent and moving clockwise...
North East Continent
Ledun, Dalerad, Kalnor, Dwarven Holds, Barbarian Holds, Eastern Coalition, Pentath, Yulan.
Iliana, Adavad, Narkissos, Zenon
Western Continent and Islands
Lopaka, Palila, Elnar, Goran, Western Coalition, Goronwy, Zsalt, Haidar, Noam, Phelan, Castell, Sanctum, Ergheith
There are lots of lands for me to write about, and I have lot I will share as this world grows. I really want to get to a point where I write multiple books - taking place in different epochs of this world. I have ideas to write the pre-history and another for a story to take place in a modern or future technology era as well. That is for the future - for now I am making this trilogy go places.
If anyone wants more details on a country, let me know and I will make a post about a specific country and its culture, history, etc.