Take on a YouTube video from Carbon Standards International AG, originally posted 2026-05-01. Watch the source: https://www.youtube.com/watch?v=z1wNkCCxqQk
Public Consultation – Global Biochar C-Sink (Version 4.0) is a webinar from Carbon Standards International (CSI) walking through the proposed v4.0 update to its biochar carbon sink methodology. Patritzia, CSI’s chief standard officer, presents the headline change: a new upper persistence class — “C-Sink 1000+” — requiring 90% geologically persistent carbon, validated by either hydropyrolysis (HyPy) or random reflectance analysis. Public consultation is open with a target effective date of May 22.
What’s actually new here: CSI is the first registry to bake reflectance-based persistence measurement directly into a biochar protocol, rather than relying solely on the H/C ratio proxy that’s dominated the field since the IBI guidelines. The threshold logic is specific — mean random reflectance above 0.8, fewer than 3% of measurement points below 2%, Gaussian distribution with a heterogeneity score under 8 — and the analysis runs roughly €200 per sample through endorsed labs accessible via CSI’s bch.tool. The “geological persistent carbon” rename (formerly PAC, polyaromatic carbon) is cosmetic, but the methodological shift isn’t. CSI is also explicitly aligning with the EU’s Carbon Removal Certification Framework, where reflectance-based persistence determination is mandatory for the 1,000+ year permanence tier.
The second item worth flagging is the new “C-Sink Matrix Provider” role for actors who only embed biochar into a finished product (concrete, asphalt, soil blends) without producing it. This is a workflow change that matters if you’re tracking chain-of-custody questions in biochar-in-materials projects.
For context: this lands in the middle of an active fight over how to measure biochar permanence credibly. The Sanei et al. 2024 paper in Biochar (and the broader Schmidt/Hagemann line of work) pushed reflectance microscopy as a more direct measure of aromatic condensation than H/C ratios, and Puro.earth has been wrestling with similar permanence-tiering questions in its own biochar methodology. The EU CRCF certification methodologies are the gravitational pull behind CSI’s move — registries that don’t align will be selling into a smaller European buyer pool. Buyers who’ve been paying the same price per ton regardless of feedstock or pyrolysis temperature now have a defensible reason to discriminate.
Useful for biochar producers planning 2026 issuances, buyers writing offtake terms that reference permanence tiers, and methodology folks tracking CRCF alignment. Skippable if you’re not in the biochar value chain.