Flo de Haan wrote:
say in the period 0-2000 AD.
I'm thinking of something too, but in my thoughts the game will be played on the whole world. The first cities will come up about 0AD and the game ends in the near future.
In such a timespan there will be calamities for only a part of the period, so in this game I think of making a nontradable calamity (what always happens), a early tradable calamity and a late tradable calamity. For example, an early tradable calamity is Slave Revolt and a late calamity is Pollution. Civilizations who have purchased Industraliazion are immume to Slave Revolt, but become vulnerable to Pollution (and are no longer immume to it.)
A nice example of an advance of the future is Chaos Theory. If one has purchased this, he/she can predict (and influence) all what is caused by small fluctuations (a butterfly who causes/prevents a hurricane etc) and therefore may trade away nontradable calamities (for example the hurricane.)