You have a point, but if your mind has already been made up then what difference does it make how I see it?
> But if I honestly think that my example isn't going to change anybody else's mind, then it's not a "cop-out" to take a flight anyway because the marginal contribution to climate change is down in the noise.
You too are somebody, and if you can't convince yourself that your actions ultimately (especially when taken over a lifetime) add up to something tangible then I'm not sure what I could say to you that would change your mind.
But let's just for a moment assume that everybody thinks like you: that would be one world. And then let's imagine a world where people are more likely to think like me, that would be another world. My argument is that those worlds will materially differ and it is all those small decisions that made the difference.
It's a bit like war: if all the soldiers would refuse to fight the war would end, immediately. But as long as they all collectively believe that their action or inaction will not make a difference the war will go on.
Yes, we're part of a collective. But responsibility is carried by all of us, individually, and that responsibility can't be waved away by saying 'my actions make no difference'.