Does the receipt actually give a number for how much CO2 emission was caused by each item? It would be interesting for customers to be able to compare that to

Does the receipt actually give a number for how much CO2 emission was caused by each item? It would be interesting for customers to be able to compare that to something like the CO2 emitted by their car on their journey to and from the shop (assuming their car is at least partially/indirectly powered by fossil fuels). Also I wonder if the amounts should be net of some minimum amount of CO2 per calorie. Assuming people aren't going to opt to not consume enough calories to live, and given that there is a minimum carbon footprint necessary to provide those calories, then I think that should be counted as a baseline or "allowance". There is always a danger with gimmicky policies that they exploit the brain's "availability bias" and make us think we are having a big impact on a problem while actually distracting us from less obvious but higher priority (and higher impact) solutions.