Comment by matt4077

This thread is already insane in that the metaphor is getting more complicated than what it was trying to explain, but...

...trying to minimise one's carbon footprint is, quite obviously, an iterated prisoner's dilemma: you can observe other's behaviour every day (and vice versa) and react accordingly.

The problem is that nobody plays it with a single other person, but with "all of humanity" instead. Any change in others' behaviour will almost certainly be only gradual, and not accessible to daily perception.