The way I understand the pollution mechanics as described in this game is:
Pollution limits everyone's economies (including the non-polluting players)
Introducing non-polluting technologies requires research (possibly cooperative)
Critical pollution ends the game
Therefore, one of the (best?) "meta", "emergent" strategies will be to go all-out-polluting FIRST and prisoner dilemma it so that we finish just below the critical threshold, but with you on top.