CDR Verification Framework Documentation
Docs: Component
Change in agricultural lime use
Uncertainty
In agricultural contexts, fine grained carbonate limestone (agricultural lime) is commonly applied to raise the pH of acidic soils. As the lime weathers, it may serve as a sink or source of carbon dioxide depending on the time frame considered, the extent of strong acid weathering, and the degree of secondary carbonate precipitation, among other factors. Weathering of a mole of carbonate can remove one mole of carbon dioxide. Any change in lime use because of a CDR deployment requires accounting for the corresponding change in carbon removal. Lime weathering efficiency may be reasonably well-known at sites that have applied lime for years, but tracking the fate of lime-derived carbon remains a challenge. If no liming occurs prior to a deployment, or the CDR deployment does not change liming behavior, the uncertainty of the liming counterfactual is not applicable.
Applicable pathways
Pathway
VCL
Biochar
1-3
Revision history

Apr 01 2024
Edited for clarity.

Oct 11 2023
Edited to reflect that lime weathering can be a carbon source or sink.

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

Sep 19 2022
First release.
Change in agricultural lime use
Uncertainty
In agricultural contexts, fine grained carbonate limestone (agricultural lime) is commonly applied to raise the pH of acidic soils. As the lime weathers, it may serve as a sink or source of carbon dioxide depending on the time frame considered, the extent of strong acid weathering, and the degree of secondary carbonate precipitation, among other factors. Weathering of a mole of carbonate can remove one mole of carbon dioxide. Any change in lime use because of a CDR deployment requires accounting for the corresponding change in carbon removal. Lime weathering efficiency may be reasonably well-known at sites that have applied lime for years, but tracking the fate of lime-derived carbon remains a challenge. If no liming occurs prior to a deployment, or the CDR deployment does not change liming behavior, the uncertainty of the liming counterfactual is not applicable.
Applicable pathways
Pathway
VCL
Revision history

Apr 01 2024
Edited for clarity.

Oct 11 2023
Edited to reflect that lime weathering can be a carbon source or sink.

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

Sep 19 2022
First release.