Plastic-free packaging, how do you flag it and disclose the carbon footprint?

Two-step UX:

1. PDP flag, a "Plastic-free packaging" badge as a Magento product attribute, rendered next to the cert flags. Click-through modal explains the packaging material (mushroom foam / molded pulp / kraft / FSC paper) + the kg-CO2 footprint per unit.
2. Checkout choice (optional but powerful), at checkout, customer picks between plastic-free (default, e.g. molded pulp) or standard recyclable (cheaper, lower-impact-disclosed-honestly option). Each shows the cost delta + kg-CO2 delta. Magento sales-rule or custom checkout step. Default to lower-impact.

Carbon footprint disclosure: get the kg-CO2 per packaging option from your supplier (most plastic-free vendors like EcoEnclose, Noissue, Sourcing Genius, Hero Packaging publish LCAs). Store as a product attribute. Render as "+0.2kg CO2 vs standard" or similar at checkout. Pela Case ships this UX; Who Gives a Crap discloses packaging origin + recyclability on every product page.

FTC Green Guides specifically warn against unsubstantiated "biodegradable" / "compostable" / "eco-friendly" claims. The fix is specificity: "compostable in industrial facilities (BPI-certified)", not just "compostable." Magento attribute set captures the exact claim language with the certifying body link.