Turn Points are an abstract in-game representation of time passing. Some actions cost TP, some cost $ (dollars), some cost PC (Political Capital), and some cost a combination of the three.
Player Actions : Costs : Profits
Logging : -TP, -$ : +$
Surveying : -TP : +$
Building/Developing : -TP, -$ : +$ (once people move in)
Planting Trees : -TP : +PC (e)
Commissioning Anything : -$ : (ability to modify land)
Actions that progress in Game Time but are outside of the player’s control:
people moving into and out of houses
animals reproducing or dying or moving habitats between tiles
zoning laws changing
players losing money over upkeep (of companies and assets)
More About Political Capital
PC can be pro-environment (e) or pro-humanity (h). Players can spend PC to make the government change laws in their favor, but PC are more efficient if they are aligned to the goal. For example, if you want to preserve an area of land for an endangered species, it will cost 4 PC (e) but 8 PC (h).