What about having some more consequenses for what you do. I the real world there is a reason that people are worried about cutting down rainforest. There are a few ideas here
Battleground:
When enough battles have been fought on a certain square that square will drop to zero production. After some time it will regain (as people build up the countryside again)
Forests:
Have some kind of penalty if you just cut down all the rain forest and forest. Make it so there has to be a certain number of forest squares to sustain x number of population. Else people start dying because of air need.
Unions:
As the world is today there is great consequenses for going to war. Make it so that after the UN is built other nations will declare war at you if you attack a weak neighboor. Also perhaps make other unions like NATO as a type of strong MPP
That way nations will come to feel for that do. As it is now the only consequens is the global warming, and that everyone declares war at you if you use nukes.
Battleground:
When enough battles have been fought on a certain square that square will drop to zero production. After some time it will regain (as people build up the countryside again)
Forests:
Have some kind of penalty if you just cut down all the rain forest and forest. Make it so there has to be a certain number of forest squares to sustain x number of population. Else people start dying because of air need.
Unions:
As the world is today there is great consequenses for going to war. Make it so that after the UN is built other nations will declare war at you if you attack a weak neighboor. Also perhaps make other unions like NATO as a type of strong MPP
That way nations will come to feel for that do. As it is now the only consequens is the global warming, and that everyone declares war at you if you use nukes.