Estimating farm-scale greenhouse gas emission intensity of pig production in Norway

To assess greenhouse gas (GHG) emission intensity and its variation in Norwegian pig production, we conducted an analysis of 15 farrow-to-finish pig farms to calculate farm-scale emissions of GHGs, expressed as carbon dioxide equivalents (CO₂eq) per kg carcass weight (CW) sold. A model, HolosNor, was developed to estimate net GHG emissions, including soil C changes, from pig farms. Based on data from 2008 the estimated GHG intensity was 2.65 kg CO₂eq kg⁻¹ CW (range: 1.24–4.03). The production of the feed consumed by the pigs contributed most to total GHG emissions; accounting for 2.14 kg CO₂eq kg⁻¹ CW, or more than 80% of the total emissions. Our study estimated a large variation in GHG intensity among pig farms in Norway which indicates opportunity for incorporating mitigation practices. A valuable contribution of the current work is the framework of a farm-scale tool for assessing farm-specific mitigation options.