Anyway, I still find it unrealistic they'd want to poison their entire moon just to get some energy. One winter isn't gonna be their downfall.
...Right, it would be much more realistic if they poisoned their own planet just to get some energy.
If you have absolutely no heating whatsoever one winter could be their downfall. You know how many people froze to death in Jamestown?
Would it have been better to help them with what's available? Sure, only nothing was available, the Cardassians took it all. Besides chopping wood there's not a whole lot they can do.