CDR Verification Framework Documentation
Docs: Component
Soil carbon impacts
Uncertainty
CDR deployments could affect soil carbon stocks through a variety of mechanisms. If a CDR project results in soil carbon loss, for example by disturbing the soil during the construction of a carbon storage site, we recommend this loss be incorporated into the calculation of net carbon removal. Conversely, if a CDR project results in increasing soil carbon stocks, for example by adding ammendments like minerals or biochar that could potentially induce positive changes to soil carbon, we recommend that these changes not be included in the calculation of durable carbon removal due to the impermanence of soil carbon storage. Soil carbon varies by site and depth, and quantifying soil carbon stock changes should rely on rigorous soil sampling.
Applicable pathways
Pathway
VCL
Biochar
1-3
Revision history

Apr 01 2024
Edited to reflect the range of possible soil carbon affects (both positive and negative) during a round of updates and pathway additions.

Jun 29 2023
Fixed typo.

Apr 10 2023
Edited for cross-pathway consistency in response to the addition of the Biochar pathway.

Dec 19 2022
Second release. Edited component to reflect the possibility mineral weathering may also drive outgassing from soils. These edits occured as part of a broader update of the Enhanced Weathering pathway.

Sep 19 2022
First release.
Soil carbon impacts
Uncertainty
CDR deployments could affect soil carbon stocks through a variety of mechanisms. If a CDR project results in soil carbon loss, for example by disturbing the soil during the construction of a carbon storage site, we recommend this loss be incorporated into the calculation of net carbon removal. Conversely, if a CDR project results in increasing soil carbon stocks, for example by adding ammendments like minerals or biochar that could potentially induce positive changes to soil carbon, we recommend that these changes not be included in the calculation of durable carbon removal due to the impermanence of soil carbon storage. Soil carbon varies by site and depth, and quantifying soil carbon stock changes should rely on rigorous soil sampling.
Applicable pathways
Pathway
VCL
Revision history

Apr 01 2024
Edited to reflect the range of possible soil carbon affects (both positive and negative) during a round of updates and pathway additions.

Jun 29 2023
Fixed typo.

Apr 10 2023
Edited for cross-pathway consistency in response to the addition of the Biochar pathway.

Dec 19 2022
Second release. Edited component to reflect the possibility mineral weathering may also drive outgassing from soils. These edits occured as part of a broader update of the Enhanced Weathering pathway.

Sep 19 2022
First release.