Sch 2Hybrid approach to estimating soil organic carbon sequestration

Schedule 2—Hybrid approach to estimating soil organic carbon sequestration

 

This Schedule provides for the calculation of the change in soil organic carbon stocks in a CEA between the last estimation event in the CEA for a reporting period and the first estimation event in the CEA, with a specified probability of exceedance, in tonnes of soil organic carbon for a CEA in the project area (View image in the official source for the purpose of section 25 of this determination. An estimation event represents a point in time for which carbon stocks in a CEA are estimated using sampling, modelling or a combination of the two estimation approaches.

Division 2 provides that for a CEA, soil organic carbon stock estimates must be provided at each estimation event, which, except for the first estimation event, must occur not less than one year and not more than five years after the last estimation event. Additionally, sampling in the CEA must occur such that the first estimation event is measurement-based or model-assisted, and that subsequent sampling must occur at least once every 10 years to validate modelled estimates.

Division 3 outlines the approach to working out soil organic carbon stocks for the 0-30 cm and 0-x cm layers. Data on the 0-30 cm layer is included in offsets reports to help Australia report its removals of greenhouse gases in its National Inventory Report.

Division 4 sets the Equivalent Soil Mass for a CEA for which the carbon stocks are compared over time from the first estimation event.

The mean and variance of the carbon stock for the equivalent soil mass, is worked out for a CEA for each estimation event, in tonnes CO2-e. For this purpose, project proponents can either use:

-  measurement-based estimates from soil core samples (Subdivision 2 of Division 4), using only the samples taken from the CEA for that estimation event;

-  model-only estimates (Subdivision 3 of Division 4) that have been validated in other CEAs in accordance with the requirements of the Supplement; or

-  model-assisted estimates (Subdivision 4 of Division 4), that use modelled estimates in conjunction with measured estimates from model-validation samples collected within the CEA after the modelled estimates have been provided to the Regulator. The model-validation sampling also allows model statistics to be worked out (under Subdivision 4 of Division 4) for the purposes of informing model-only estimates in other CEAs in accordance with the process set out in the Supplement.