Global Artisan C-Sink: roles, documents and dMRV explained
The Global Artisan C-Sink is Carbon Standards International's standard for the carbon stored in biochar made with Kon-Tiki (flame-curtain) kilns and other low-tech production units in low- and middle-income countries. A project is run by an organisation CSI calls the Artisan C-Sink Manager. It works with service providers that hold a CSI endorsement, and an independent validation and verification body checks it before its C-sinks reach the Global C-Sink Registry. This post sets out those roles and points to the CSI document that answers each planning question.
What the Global Artisan C-Sink standard covers
The Global Artisan C-Sink standard page describes the standard as covering "Biochar production in lower-income countries". In CSI's words, it "guarantees that feedstock is grown sustainably and that biochar is made the artisan way, using Kon-Tiki (flame-curtain) pyrolysis to keep production emissions low."
The page's eligibility rules shape how a project is set up:
Location. The project must be "located in low- or middle-income country according to the World Bank classification". The World Bank's country and lending groups are the reference.
Scale. "Biochar production does not exceed 100m³/year for a single C-Sink Farmer or 1500m³/year for a single Artisan Pro and is done with a low-tech production unit."
No double certification. Farmers and producers must not be "certified under any other methodology for nature-based climate service".
Fair pay. "Involved parties have to be compensated fairly and transparently."
Which version applies
On 7 November 2026 the CSI page lists version 2.1A as the current standard text, with a track-changes copy and the earlier versions 2.1, 2.0 and 1.0 still available. Our own Carbon Standards International alignment page lists the standard as "Global Artisan C-Sink Standard, v2.1". Plan against the version on CSI's page, and check it again before validation, because CSI also publishes rule updates (for example on Dry Matter Assessment) between versions.
Who does what in an artisan C-sink project
The standard page splits the work between the organisation that runs the project and the parties that serve or check it.
Producers. The eligibility rules name two kinds of producer, the C-Sink Farmer and the Artisan Pro, each with its own production cap. CSI has also published a clarification on increased production allowance for Artisan Pro. If your producers are close to the cap, read it alongside the standard.
The Artisan C-Sink Manager. The page lists endorsed managers under the heading "Organisations running Artisan projects". The first of the three certification phases is "The endorsement phase by CSI to check if the Artisan C-Sink Manager fulfil basic requirements and the understanding of the process." What the manager has to do after that is set out in the standard and in a separate CSI document on endorsement, validation and verification of the Artisan C-Sink Manager. We have not summarised those duties here: read them in the source.
Endorsed service providers. The page has separate endorsement routes and lists for three kinds of provider:
System providers, the low-tech pyrolysis technology. A manager who wants to build its own kiln design is welcome to, but that "will require a separate endorsement for the project".
dMRV providers, the digital monitoring, reporting and verification systems.
Laboratories. The page describes their work as checking carbon sequestration calculations and the quality of the biochar produced.
Independent verification. After endorsement comes validation, which checks "whether a project meets all rules and requirements from the Global Artisan C-Sink standard" and is carried out by "approved, qualified and independent Validation and Verification Bodies (VVB)". Verification then confirms that the outcome in the project design document (PDD) has been achieved, and it "includes an on-site inspection by the VVB". The CSI page also states that "CERES-CERT AG is the third-party auditing body for the standards owned by Carbon Standards International". CERES-CERT has its own page on the artisan standard.
Registry and trading. The page describes the standard as opening a route for farmers and cooperatives "to access carbon markets through the Global C-Sink Registry". It also notes that "C-Sink Traders are authorized to conduct both transfers and retirements in the Global C-Sink Registry", and CSI publishes a separate endorsement process for traders.
dMRV and the route from kiln to registry
The CSI page gives dMRV its own section. It notes "an increasing demand for digital Monitoring, Reporting, and Verification (dMRV) provider in the biochar production sector, particularly focusing on smallholder farmers", lists the endorsed dMRV providers for the Global Artisan C-Sink, and explains how a new provider can apply.
The application rules sit in CSI's document on the endorsement of dMRV for Global C-Sink. It includes a section of specific requirements for the Global Artisan C-Sink Standard. If you are choosing a monitoring system for artisan biochar, read that section together with the standard text to see what the system has to do.
Monitoring data then follows a set route. CSI publishes a bulk upload template and a monitoring report template, and says: "These templates are used to submit project monitoring data to the C-Sink Tool, where the data is processed for transfer to the Global C-Sink Registry." The template now also takes the Dry Matter Assessment results, so that dry matter data arrives together with the monitoring information.
For a project developer, the practical steps are short. Check the endorsed dMRV provider list on the CSI page and read the artisan section of the dMRV endorsement document. Then ask your VVB how your monitoring data should reach the C-Sink Tool, before you build a monitoring plan around any app.
The CSI documents to read before the first burn
Most planning questions for an artisan project have a CSI document behind them. The table below maps common questions to documents listed on the standard page on 7 November 2026. It lists titles only. It does not summarise what each document requires, so read the document itself.
Planning question | Document listed on the CSI page |
|---|---|
Is our feedstock allowed? | Clarification: Positive List of Permissible Biomass for Artisan |
How do we quantify biochar from a Kon-Tiki? | Clarification: Bulk density analysis for biochar produced in a Kon-Tiki; Rule update: Dry Matter Assessment; Clarification: Dry Matter Assessment - Laboratory Protocol |
Are our measuring tools good enough? | Calibration of Measurement Equipments |
Which laboratory can analyse our samples? | Laboratory Endorsement Process for Global Artisan C-Sink, and the endorsed laboratories list |
How does the manager keep control of a producer network? | Guide to develop the Internal Control System; Producer list; Farmer's Declaration of honour, example |
How should producers be paid and treated? | Labor rights and working conditions |
How do we handle methane? | Clarification: Methane emission compensation; the Methane Calculation Tool |
How do we design and size the project? | PDD template; Validation and re-validation of PDD; Calculation Ex-Ante Estimation |
How do results reach the registry? | Monitoring report template and annex; Bulk upload; Required information to upload a C-Sink Unit; Flowchart and documentation of C-sink creation |
What if we work through a local partner? | Clarification: Implementation Partner |
Methane compensation
The CSI page says the PDD "describes your project activity, from biomass sourcing to the methane compensation plan", and it links a Methane Calculation Tool and a clarification on methane emission compensation. We do not reproduce the method or any default values here. Take them from those documents and the current standard text.
Our view on field records
What follows is our view from general field-data practice, not a summary of the standard. A record is easier to stand behind when every producer uses the same measuring routine, when each photo can be tied to one batch on a known date, and when every sample is labelled so it can be traced back to its feedstock. Settle those routines with your manager team and VVB before production starts, then check them against the standard text.
Where community tools fit next to the certified data chain
CitizenClimate's data is structured to align with the monitoring requirements of Verra VCS, Gold Standard, Plan Vivo, Puro.earth and Carbon Standards International. CitizenClimate is not certified, accredited or endorsed by any standard body, and it does not issue credits.
That matters here because CSI runs its own endorsement route for dMRV providers under this standard, and CitizenClimate is not an endorsed dMRV provider. CitizenClimate has said it is engaging with CSI about the endorsement pathway. Until an endorsement exists, a project should not use our app in place of an endorsed dMRV provider, or for the monitoring data it submits through the C-Sink Tool. There is no connection from CitizenClimate to the Global C-Sink Registry.
What the app does today is described in the App Guide and the Data Integrity and Methodology Protocol:
Surveys can include photo and GPS questions, and some questions only appear after certain answers.
Records made offline keep their original timestamp, and the sync date is recorded separately.
Submissions can never be deleted. Faulty ones are archived with a reason from a fixed list.
Many lessons end with a short quiz, and members can file grievances without their name being shown to the project developer.
A read-only VVB role gives an auditor direct access to project data, and data exports as CSV or JSON.
A manager might use tools like these for records outside the certified monitoring data, such as training sessions, community feedback, or grievances about pay and working conditions. CSI lists a guide to the Internal Control System and a document on labour rights and working conditions. Whether records like these belong in your internal control system, and in what form, is a question for CSI and your VVB.
Our biochar MRV page shows how a biochar supply chain can be set up on the platform for larger producers. An earlier post on community-led biochar verification covers the community side. The walkthrough film below follows Serra Clara Biochar, a fictional project with illustrative figures. It is not an Artisan C-Sink project.
Frequently asked questions
What is the Global Artisan C-Sink?
It is a Carbon Standards International standard for biochar made the artisan way, with Kon-Tiki (flame-curtain) kilns or other low-tech production units, in a low- or middle-income country according to the World Bank classification. An endorsed Artisan C-Sink Manager runs the project, an approved VVB validates and verifies it with an on-site inspection, and monitoring data reaches the Global C-Sink Registry through the C-Sink Tool.
How much biochar can one producer make under the standard?
The CSI standard page caps production at 100m³/year for a single C-Sink Farmer and 1500m³/year for a single Artisan Pro, made with a low-tech production unit. CSI has also published a clarification on increased production allowance for Artisan Pro. Read both, and check the current version of the standard, before you plan a producer network around these limits.
How do I choose a dMRV system for an artisan biochar project?
Start with the list of endorsed dMRV providers for the Global Artisan C-Sink on the CSI standard page. CSI's document on endorsement of dMRV for Global C-Sink includes a section of specific requirements for this standard. Read that section and the standard text, and ask your VVB how your monitoring data should reach the C-Sink Tool, before you commit to any system.
Is CitizenClimate an endorsed dMRV provider for artisan biochar?
No. CitizenClimate is not certified, accredited or endorsed by any standard body, and it does not issue credits or connect to the Global C-Sink Registry. CitizenClimate has said it is engaging with CSI about the endorsement pathway. Today its app can collect timestamped survey records for work outside the certified monitoring data. Each record holds whatever photos and GPS points its survey asks for.
Read the standard before you plan the network
The Global Artisan C-Sink puts a lot of weight on the organisation that runs the project and on the documents CSI publishes around the standard. Read version 2.1A and the relevant clarifications first, and talk to your VVB before production starts. If you want to see how community surveys and grievance records work in the field, download the free app or read the App Guide.
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