# Enhanced rock weathering

## Purpose

This methodology covers durable carbon removal through enhanced rock weathering. This includes crushing and spreading specific types of rocks on agricultural soils to increase the rock's surface area exposed to the atmosphere, which speeds up the naturally occurring rock weathering and CO$$\_2$$ removal process.

<table data-header-hidden><thead><tr><th width="234"></th><th></th></tr></thead><tbody><tr><td><strong>Methodology name</strong></td><td>Enhanced rock weathering</td></tr><tr><td><strong>Version</strong></td><td>1.0</td></tr><tr><td><strong>Methodology ID</strong></td><td>RBW-ERW-V1.0</td></tr><tr><td><strong>Release date</strong></td><td>October 17th, 2025</td></tr><tr><td><strong>Status</strong></td><td>In use</td></tr></tbody></table>

{% hint style="warning" %}
Although rock weathering is a well understood and proven natural phenomenon, accurately measuring CDR from ERW still has major uncertainties and can be considered in the research stage.

The following methodology was developed in consultation with scientists and Project Developers, and uses the best available knowledge. However this knowledge is rapidly changing and critical research is ongoing that is expected to modify, improve or clarify the present methodology.&#x20;

To that end, Rainbow encourages Project Developers to contribute to this ongoing research, by going beyond the minimum requirements outlined herein for carbon credit certification.
{% endhint %}

See the glossary for methodology-specific terminology :point\_down:

{% content-ref url="../glossary" %}
[glossary](https://docs.rainbowstandard.io/~/changes/215/glossary)
{% endcontent-ref %}

<details>

<summary><strong>Acknowledgements</strong> <span data-gb-custom-inline data-tag="emoji" data-code="1f91d">🤝</span></summary>

*This methodology was developed by Riverse with valuable input and support from the Riverse Enhanced Rock Weathering Methodology Working Group members and other expert contributors.*&#x20;

*We would like to thank Alison Tune and Noah Anderson (Cascade Climate); Elliot Chang and Henry Liu (Lithos); Matthew Healy, Rosalie Tostevin, Beatrice Mocci, and Tzara Bierowiec (UNDO); Brian Rogers (Stanford University); Steve Swanson (feedstocks.earth); and Matthew Clarkson (InPlanet); and Simon Manley (Sylvera), Maria-Elena Vorrath (University of Hamburg & CDRExperts),* *for their insights and contributions throughout the development process.*

*We would like to especially acknowledge Cascade Climate's "Foundations for Carbon Dioxide Removal Quantification in ERW Deployments*" [*report*](#user-content-fn-1)[^1]*, which provided essential technical guidance and framing that informed many of the recommendations and assumptions adopted in this methodology.*

</details>

[^1]: Mills, J. V., Sanchez, J., Olagaray, N. Y., Wang, H., and Tune, A. K., 2024; Foundations for Carbon Dioxide Removal Quantification in ERW Deployments, Cascade Climate. [URL](https://cascadeclimate.org/CC_Foundations%20for%20CDR%20Quantification%20in%20ERW%20Deployments.pdf).&#x20;
