Discover the new update to the Global Biochar C-Sink Standard

Dear ,

We are pleased to announce that the Global Biochar C-Sink Standard has
received a minor update. It is now available in version 3.2. The update came into
effect on November 15, 2025.

We are pleased to present the content of the changes:

Revision of the assessment of mineral matrices

We have revised the assessment of the persistence of biochar in mineral
matrices. You can find a summary of the effects in the

Biochar is completely protected in concrete for 100 years

The 100 years = 100% principle now applies to biochar in concrete. If biochar is incorporated into building materials that use cement, lime, clay, gypsum, or geopolymers as binders, the biochar is completely protected for 100 years.

A 100 year C-sink (CINK100) with 100% is issued. 75% of the carbon incorporated into concrete is stable for at least 1000 years. This portion can be used to offset manufacturing emissions. Read all the details in Chapter 12.3.

Asphalt now counts as a geological sink

The asphalt matrix has been reevaluated so that long-term sinks (CINK1000+) can now also be issued for biochar in asphalt. For concrete, the 100 years = 100% principle applies.

However, for asphalt, a margin of 5% of the carbon content is deducted before registration. For full details, see Chapter 12.4.

Inclusion of all regulations on diffuse C-Sinks that came into force on October 15, 2025

Since October 15, 2025, there is no longer an obligation to track to the end point if the biochar has been mixed into an approved C-Sink matrix.

All matrices for which tracking to the end point is voluntary are marked "Diffuse C-Sink authorized" in the matrix positive list. Tracking the C-Sink to the end point remains possible at any time – and is expressly recommended.

These changes have been included in version 3.2. We provided detailed information about this in our newsletter dated September 16, 2025. Please feel free to read it again.

Further explanation on the offsetting of methane emissions

Methane emissions can occur during the production of biochar. CINK1000+ can be used to offset these emissions, but this is not mandatory.

Instead, 20-year C-Sinks (CINK20) can also be used to offset the climate impact of methane over 100 years. The standard now explains this logic in greater detail.

We look forward to continuing to work with you to cool the climate through biochar C-sinks.

If you have any questions or concerns, please contact

Kind regards,

Carbon Standards International AG

Patrizia Pschera
Technical Expert Biochar/Climate

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