SECTOR: GHG calculation tailored for cropland

Integration of SECTOR within an MRV framework for agriculture. Although the acronym MRV is semantically ambiguous, there is broad consensus that MRV is needed to track the efficiency of mitigation options and to ensure transparency and credibility of results. However, the bulk of the literature dealing with MRV issues addresses its role at the national level for planning and implementing NDCs. MRV frameworks at project scale have only vaguely been defined at present.

The new features of SECTOR address some of the major challenges for developing sound concepts for an agricultural MRV framework. For instance, the diversity of crop management practices makes it difficult to account for them in the other calculation tools that assume one uniform practice in a given area. Given the significance of water regimes for overall emissions, mitigation projects will have to establish a solid baseline by recording the frequency of farmers following a certain practice that can then be compared to the situation at the end of the project.

The reliability of IPCC default values for point sources in agriculture (including rice fields) has recently been questioned. At the national level, the rationale for using one global default value is that local deviations in terms of very high or low emission rates will somehow level off at the national scale. As such, it is not really surprising that locally obtained emission rates deviate from the national–or global–default values used in any given GHG calculator. But this disparity between local and default EFs does not necessarily speak against using the IPCC approach as such, and only corroborates the need for disaggregation of EFs to be integrated into the GHG calculation. Since the wealth of empirical records on emissions has not really been tapped for GHG calculations in the past, it is hoped that the new GHG calculation tool with user-friendly inputs of local data may stimulate a broader use and sharing of GHG data.

Excerpt from: Wassmann et al. 2019. Introducing a new tool for greenhouse gas calculation tailored for cropland: rationale, operational framework and potential application. Carbon Management.