If (1) our current system is unsustainable, and (2) we can't make a difference, then we are, by the most basic rules of logic, (3) headed for a collapse of our current system.

It's a bit strange how often people will aggressively make either point 1 or 2, and then concede that the other is also true, but then decry the 3rd, which follows from 1 and 2, to be ridiculous pessimism.

Eat food, not too much, mostly plants.