> Obviously this can't be universally true. It's a bit of a hand wavy argument, and the reductio ad absurdum conclusion would be that reducing global carbon emissions is impossible (which obviously isn't true). But I still think its something worth considering before making individual purchasing decisions based on perceived "greenness" to the demerit of price.

I think the reductio ad absurdum conclusion here is the degrowth-sounding argument that we need less economic activity to reduce emissions.

One thing your analysis may be missing is what you're going to do with the money saved.