I found this site looking for one specifically geared to picking products based on sustainability. I'm not sure if such a specifically-focused site would actually be more effective than this one.
The original question I had that inspired this was paper or plastic? The answer is far from obvious.
- Paper bags weight more, cost more (carbon/petrochemicals) to move around. OTOH they decompose.
- Plastic bags are, of course, plastic. They vary greatly in weight, but then the ones that are very light tend to be doubled-up.
- Reusable bags often don't get reused that much. How much reuse justifies their existence? And which kinds? Cotton bags have a huge environment impact.
This kinds of question bugs me almost every time I go shopping.