Context
In the context of greenhouse gas emission reductions from the forestry sector and REDD+, many countries and jurisdictions’ approach to uncertainty around estimates has focused on large spreadsheet tables that are near-impossible to navigate for anyone but their developers, reducing transparency and effectiveness of verification.
Simplifying simulation-based uncertainty analysis of REDD+ greenhouse gas emission reductions may not be possible or desirable. Over-simplification could result in uncontrolled bias or misrepresent the actual uncertainty around volumes of emission reductions.
The {mocaredd} tool aims at solving two critical issues with over-complicated spreadsheets-based calculations:
- Split the information into several tables with keys to merge data for calculations. Inspired for database management systems for their efficiency and simplification of data structure.
- Process the simulations with a statistical language rather that spreadsheet tool, again for efficiency purpose. The authors also believe that once the carbon accounting calculation chain is well understood by parties, adding the simulations doesn’t need to be visually highlighted, and are safer run programmatically than on spreadsheets.
To do so, {mocaredd} is built as a R package that provides calculation functions and a XLSX workbook that contain the initial data in a structured and easy to navigate way.
This guideline provides instructions on how to fill in the template workbook to ensure all matrices of land use change are reported, with all their associated carbon elements, and for all the reported time periods.
1 Overview of the template
The template is built around four tables to encompass all the information necessary to:
- re-construct the arithmetic means (not based on simulations) of all emissions and removals and emission reductions (ERs).
- run simulations for all the input variables of areas and carbon elements,
- Get simulation-based emission reductions with their associated uncertainties.
- Run sensitivity analysis to highlight the main contributors to the ERs uncertainty.
These four tables are designed to describe separately:
- User inputs to bring flexibility to the calculation algorithm. For example are the land use change expressed in hectares per year or in hectares, or are the carbon stock expressed in tons of dry matter or tons of carbon.
- Time periods for the different datasets used in the calculations and with REDD+ period do they belong to, reference or monitoring.
- Areas of land use change, for each time period and each combination of land use, what is the area and it’s standard error.
- Carbon elements, combining carbon pools and other carbon related elements such as carbon fraction, or degradation ratios if expressed as a percentage of their intact land use.
Detailed information for each table is presented in the following sections.
2 User inputs
This table contains a few parameters to allow the tool to handle as many configurations as possible.
| Col. name | Label | Type of value | Example | Description |
|---|---|---|---|---|
| trunc_pdf | use truncated PDFs? | TRUE/FALSE | FALSE | Specify if truncated PDFs should be used or not. |
| n_iter | Number of iterations | integer | 10000 | Specify the number of simulations to run for each PDF. |
| ran_seed | Random seed | integer or NULL | 31 | If NULL, the tool generates a random seed each time. Set a seed number to fix the random number and make the analysis reproducible. |
| dg_ext | Degradation extension | text | “_deg” | Specify to suffix used to differentiate degraded and intact versions of the same land use. Required if degradation is a carbon ratio. |
| dg_pool | Degradation pools | text, comma separated | AGB, BGB | List the pools affected by degradation (experimental, should always be AGB, BGB, DW) |
| ad_annual | Is AD annual | TRUE/FALSE | TRUE | Specify if the Activity Data is reported in hectares (ha) or hectares/year |
| conf_level | Confidence level | numeric | 0.9 | Confidence level of the uncertainty. The quantiles representing the upper ad lower bound of the confidence interval. |
| round_digits | Rounding number of digits | integer | 3 | Number of digits to round calculations. |