This Swedish study by Christel Cederberg and Berit Mattsson, Department of Applied Environmental Sciences, Göteborg University, Sweden, (Journal of Cleaner Production 8 (2000) 49–60) compared organic and conventional dairy production. It concluded that the organic sysem generated slightly fewer GHG emissions than the conventional. A life cycle assessment was performed on an organic and a conventional dairy farm in Sweden. A range of environmental impacts were considered, including the Global Warming Potential of each farm. The study found that per kg of milk, the organic system had slightly lower emissions. The emission comparisons for individual GHGs are as follows: Carbon dioxide: This was lower for organic systems. Lower levels are largely accounted for by the absence of energy intensive nitrate fertilisers in the organic system. Nitrous oxides: emissions were lower for the organic system Methane: emissions were higher in the organic system due to their higher intake of roughage fodder. Methane emissions made the largest contribution to overall GWP in both systems.