So at a super rough estimate, ads cause 1-2% of US emissions. That only accounts for emissions associated with making the extra stuff ads convince people to buy, but of course a lot of the stuff we buy (e.g. cars) also emits when we operate or use it. Not sure how to ballpark-estimate that portion.

Interesting approach. I guess to be more precise one would have to take into account ads for toothpaste and goods that change the type of product you buy, not the volume