So for me, this isn't about deciding whether or not to bother making an effort for the environment but to decide where you are going to make that effort.
So it turns out that, for my youngest, a new bag and (in his case) a new coat for the start of his first proper school term in P1 was really important. I only found that out today (we're in Scotland, so term starts today). When I suggested that he could just wear the mac he'd worn to nursery as recently as last week, he bawled his eyes out. "That can't possibly happen, mum." (Apparently.) "Because that was a "nursery" mac and now I'm a schoolboy." Okaaaaay.
So it seems to me that rite-of-passage shit, like new bags and lunchboxes, may be really psychologically important to (some) kids......makes sense I guess, as kids live in an environment where their sense of self-worth is coloured by whether authority figures think they have been "good enough", so even wanting a different bag for your new teacher between P1 and P2 seems like maybe them wanting a "fresh start"?? And I make a zillion mistakes in my life every day, and feel constantly guilty, so I'm all about understanding the concept of "A Fresh Start" ;-)
So in that case, because the threat to our planet is terrifying and real, I'm going to cut back on some item of clothing that I may have otherwise got for myself (because it's fashionable, or because I think I need a new pair of trainers, or even because it really does have holes in it and need to be replaced) so that he can have this rite-of-passage thing that obviously means so much to him. And then next time, when he asks me for a piece of plastic tat in the toyshop, which he doesn't need, but actually I do really need a new pair of trainers cos the oldies have holes in, I'll refuse his request, and "save" the environmental waste there, whilst adding it to my moral account :-)