Did download it, just redownloaded it ;D. About climate change, is there any magic in the world? I know we have our evil magic (power) but do normal mortals have it as well? If so, then maybe they can do rituals to push back against climate change. Maybe even allow the player to somehow disrupt them. As for the last stand thing, how about making a "conscript" mechanic, where the corrupt nobles will draft more peasants than their nobler counterparts, which allows them to field bigger armies but they suffer economically due to lesser manpower. Then give an ability to the player if he controls a dark empire to call all peasants to form a huge peasant army, which causes the enemy to do the same to combat our peasants. This then allows a huge long war to start during which the player can start sabotaging stuff through agents or powers.
Extra: 4 Peasants -> 1 Army Strength
Extra 2:this system would probably work better with a tile system so maybe it's not fully applicable to your node system