The emissions baseline represents what would happen if your project did not occur. The emissions baseline provides a point against which you measure any changes in the amount of emissions produced by a project in a reporting period. You use this change in emissions to calculate net abatement. For soil carbon projects, the emissions baseline is the amount of emissions expected or calculated from the alternative scenario before the project starts. The baseline is calculated over the 'baseline emissions period', which is usually the five years before the project starts.
Sources and sinks of carbon described by the greenhouse gas assessment boundary are given in Section 46. However, only baseline emissions from livestock on pasture, synthetic fertiliser and crop residues need to be calculated for a soil carbon project, as shown in Table 2. Baseline lime and irrigation energy use are considered to be zero for soil carbon projects.
Table 2: Summary of livestock, synthetic fertiliser and crop residue baseline calculations that must be calculated for different project management activities and management actions
Baseline emissions calculation | Project management activity
| Sustainable intensification | Stubble retention | Conversion to pasture |
|---|
Livestock | Livestock baseline A or B as applicable (Section 55)
| Not calculated | Livestock baseline A or B as applicable (Section 55) |
Synthetic fertiliser | Synthetic fertiliser baseline A or B as applicable (Section 59) | Synthetic fertiliser baseline A or B as applicable (Section 59) | Synthetic fertiliser baseline A or B as applicable (Section 59) |
Crop residue | Pasture renovation actions—use residue baseline A (Sections 62, 63) Project CEAs under crops—use residue baseline B (Sections 62, 64) | Residue baseline A (Sections 62, 63) | Residue baseline C (Sections 62, 65) |
Figure 2: Calculating livestock baseline for each carbon estimation area
Figure 3: Calculating livestock baseline for each carbon estimation area
Figure 4: Calculating synthetic fertiliser baseline for each carbon estimation area
Figure 5: Calculating crop residue baseline for each carbon estimation area
See Figures 2-5: Equation trees for calculating baseline emissions for a project
To calculate the baseline CO2-e emissions from a modelled soil carbon project, you need to follow a sequence of equations. An individual equation tree for each emission source, in Figures 2 – 5, steps through the calculations. Equation numbers are at the top left of each box.
For livestock, if you have 1–5 years of historical stocking data for the land that now forms the CEA, use the livestock baseline A equations (see Sections 55–56). If you do not have this historical stocking data, use livestock baseline B equations (Sections 57–58), along with standard carrying capacity data given in the Standard Parameters and Emissions Factors Tables.
For livestock emissions only, you need to calculate either a standard deviation or a 10% tolerance margin, depending on whether you use livestock baseline A or B. This value is needed when you calculate your livestock emissions later in the project (using Figure 6). If emissions differ from the baseline by a standard deviation or 10% tolerance (as relevant), they must be included when calculating your net abatement.
Synthetic fertiliser baseline A has a default zero value, and is not shown on Figures 2-5. However, if you have historical fertilisation data for the land that now forms the CEA for at least three of the five baseline years, use the synthetic fertiliser baseline B equations (Sections 59–60).
Lime baseline emissions are assumed to be zero (Section 61) and are not shown on the equation trees.
Crop residue baseline A applies for projects under pasture renovation or where all crop residue is assumed to have been removed (Table 2), so the baseline is assumed to be zero. For project areas under crops (Table 2), baseline B assumes that a 20% increase in the amount of biomass will be accumulated during the project reporting period. Crop residue baselines A and B are fixed values and are not shown on Figure 2. For a project that converts crops to pasture, baseline emissions are calculated by residue baseline C (Section 65).
The irrigation baseline is assumed to be zero, as outlined in Section 66, and is not shown.
Data needed to complete the sequence of equations are drawn from a number of sources. Some data come from the National Greenhouse and Energy Reporting Regulations, some are already available for you in the methodology determination, and others are drawn from the National Inventory Report 2013 and from data you will produce as a result of running your project.