[bttrfl]

CO2 footprint would be nice, but CO2 isn't only environmental factor to consider. I'd rather have colour-coded stickers with two scales - absolute and relative within a product category.

A sticker on a diesel car would be RED/RED and a sticker on a tiny EV car would be RED/GREEN.

A sticker on an apple from a domestic market would be GREEN/GREEN and an apple imported from a country 1000s miles away would be GREEN/ORANGE.

Ideally, the labeling would be a reflection of a fiscal mechanism to charge for externalities in the entire chain - from production to a sale and disposal.

[melomal]

So it would definitely need to be category specific but I do think this could be a hugely interesting idea for organic products etc

[bttrfl]

I'd love a dual, absolute/category, scale to make my decisioning easier. If something is green on an absolute scale then it's a smaller problem if I pick a product labeled red on on category scale. But I do know that I shouldn't do that.

Dual scale would make it possible to differentiate between two similar products - an "eco" cotton bag could be orange/green while a single plastic use bag could green/red. This way every one would know that an eco bag is worse than a plastic one unless you use it a lot.

Finally, producers would be motivated to optimise environmental impact of all kinds of products because having a red label would be shameful.

[melomal]

The traffic light system is used in the UK to show how much sugar/salt/fat is in the product. To be honest it shocked me to see so much red for salt so it definitely was eye opening.

The issue with this, that I can now see, is that it would take government action to make this a requirement. But I can see that there would definitely be a benefit for education the customer.