Under the GHG Protocol, corporate value chain accounting implicitly applies a "0/0" approach to biogenic carbon, while product carbon footprinting uses a "-1/+1" approach that records both the uptake and the release of biogenic carbon. This mismatch applies only to biogenic carbon. It makes product footprints hard to use in corporate inventories and makes fair comparison between bio-based and fossil materials impossible.

The statement uses bio-based plastics to illustrate the issue: they are molecularly identical to fossil plastics, yet are treated differently at end of life. In landfill or recycling, fossil carbon is treated as stored or transferred, while biogenic carbon is treated as emitted. As a result, end-of-life choices make no difference for bio-based materials, and the full benefit of replacing fossil with bio-based materials is only recognised when they are incinerated.

What the signatories ask for:

• A consistent -1/+1 approach across both organisational and product-level carbon accounting
• Equivalent treatment of biogenic and fossil carbon in recycling and at end of life
• Methodological choices, such as the recycling cut-off approach and the time horizon for landfill, applied equally to all materials

The statement notes that corporate efforts to reduce emissions are increasingly focused on replacing fossil materials with bio-based alternatives, so the full benefits of these materials need to be captured in reporting. Bio-based materials are not enough on their own to deliver a circular economy, but by drawing carbon from the atmosphere rather than from geological reserves, they play a key role in a truly circular carbon economy.

For more information, read the full statement.