Science explainer
Policy
Can soil carbon be measured to Tier 3 without sampling?
The LSRS raises the evidentiary bar for land-sector reporting. Professor Jacqueline McGlade and David Craig, Co-Chair of the TNFD, discuss what that asks of soil measurement, and whether the data exists to meet it.
Carbon accounting runs on three tiers of evidence:
Tier 1 applies global defaults
Tier 2 narrows to regional factors
Tier 3 requires measurement of the specific land being reported on
The difference matters because soil carbon varies at the metre scale. A regional average describes a category of land, not a field.
Tier 3 has historically meant physical sampling, which is why most land has never been measured at that level. Digital soil measurement removes that constraint, and is aligned to the Land Sector and Removals Standard.