Emissions and methodologies for cropland and grassland used in the Norwegian national greenhouse inventory

Abstract

Every year the Norwegian Forest and Landscape Institute submits the national GHG inventory for the land use, land-use change and forestry sector as part of the National Inventory Report (NIR). The methodology and activity data used to estimate CO2 emissions and removals from cropland and grassland were thoroughly evaluated in 2012 and several new methods were implemented in the 2013 NIR submission. The objective of this report is to present the results of this evaluation and to provide detailed documentation of the new methodologies and the emissions reported in the 2013 NIR submission to UNFCCC for cropland and grassland (CPA, 2013). This report describes four major topics: 1) Method choice for mineral soils. The erosion-based method previously used for mineral soils on both cropland and grassland cannot be considered appropriate. It was replaced by a Tier 2 method for cropland remaining cropland (considering effects of crop rotation, tillage, crop residues and manure inputs) and a Tier 1 method for grassland remaining grassland (considering effects of grassland management practice). 2) Evaluation of the emission factor used for organic soil and the area estimate. A review of Scandinavian literature did not support changing the emission factor value but the areas of cultivated organic soils were re-defined under cropland and grassland. 3) A Tier 1 methodology that can be used to estimate soil carbon stock changes on land-use conversion to grassland and cropland as well as all other land-use change conversion. 4) Uncertainty estimation for all source/sink categories are presented including the use of IPCC default uncertainty estimates when relevant.