> For the complete documentation index, see [llms.txt](https://documentation.carbonregistry.com/documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.carbonregistry.com/documentation/icr-program/methodology-development/icr-methodologies/under-development/m-icr021.md).

# M-ICR021

16\. Carbon Capture and Storage

## Ocean Iron Fertilization-based marine Carbon Dioxide Removal (OIF-mCDR)

### Methodology developer

[Liquid Trees (10B Solutions, Inc.)](https://www.carbonregistry.com/directory/d426deca-585d-43f1-810f-11065aa4854d)

### Sectoral scope

16. Carbon Capture and Storage

### Status

Under development

### Current Stage:

Public consultation

### ID:

[M-ICR021](https://www.carbonregistry.com/methodologies/m-icr-021)

### Summary:

**M-ICR021 – Ocean Iron Fertilization-based marine Carbon Dioxide Removal (OIF-mCDR)** sets out procedures for quantifying carbon dioxide removals from controlled ocean iron fertilization in offshore High-Nutrient, Low-Chlorophyll regions. The methodology addresses projects that add bioavailable iron to a defined surface-water mass to stimulate phytoplankton growth and enhance the biological carbon pump.

The methodology uses project-specific evidence of particulate-organic-carbon export. Primary and zooplankton-mediated pathways are descriptions within a single measured qualifying POC export flux and may not be double counted. Export alone is not credited as removal: the methodology subtracts baseline export and applies project-specific requirements for atmospheric air–sea CO2 uptake, long-term durability, regional nutrient displacement, project emissions, mandatory leakage and conservative uncertainty treatment.

It also requires site-specific baseline and attribution methods, staged satellite and in-situ monitoring, environmental safeguards, permitting and verification. 

***

## Documentation

{% tabs %}
{% tab title="Methodology Summary" %}
[M-ICR021](https://www.carbonregistry.com/methodologies/m-icr-021)
{% endtab %}

{% tab title="Methodology Description" %}

#### Methodology description 

{% file src="/files/Q9O95w8h6TziXJWs5GZs" %}
{% endtab %}

{% tab title="Methodology Validation Report" %}

{% endtab %}

{% tab title="Public Consultation" %}

#### Public consultation 14. September 2026 - 14. October 2026

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[M-ICR021](/documentation/icr-program/public-consultation/methodologies/2026/m-icr021.md)
{% endcontent-ref %}
{% endtab %}
{% endtabs %}