Greenhouse gas emission reduction opportunities for the Norwegian salmon farming sector - can they outweigh growth?

Norwegian farmed Atlantic salmon is a nutritious type of food in increasing demand and although production has stagnated and is faced by various challenges, it is likely to continue to expand in the future. We present results from a detailed greenhouse gas emission assessment of the most important Norwegian farmed salmon export products along with improvement measures. By scaling up both baseline results and reduction opportunities, based on growth projections, we estimate current and future emissions of the sector as a whole. We show that export of gutted salmon to Europe by truck dominates Norwegian salmon exports, not only in volume and value, but also in emissions, followed by export of fresh gutted salmon and fillets to Asia and fillets to the US by air. The cumulative greenhouse gas emissions are dominated by feed production followed by emissions from overseas airfreighting of fresh products. The five most important emission reduction measures, based only on existing technology and without particular order were 1) slightly increased feed efficiency, 2) increased utilization of side streams occurring in secondary processing after export, 3) seafreight to market instead of road and air, 4) higher energy efficiency and cleaner energy sources, and 5) changed feed composition. Collectively, they have the potential to reduce greenhouse gas emissions of current production by 60%, from 5.2 to 2.1 million tonnes of CO2e, assuming the same relative importance of each supply chain. This implies that a medium growth-scenario, representing more than a doubling of the volume of salmon farmed to 3.3 million tonnes, would be possible while reducing total sector emissions by 16% if the improvement measures were fully implemented. For larger reductions, either lower growth or more ambitious implementation of improvement measures is needed. Although greenhouse gas emissions are often linked to resource efficiency and wider sustainability, this is not always the case, and it is important to avoid shifting burdens from climate to e.g. eutrophication or biodiversity impacts. However, many environmental impacts of salmon farming are centered around feed efficiency, and even problems with welfare, escapees, and in part eutrophication are reflected in lower feed efficiency resulting in higher greenhouse gas emissions. In addition to the systematic collection of robust data for more continuous monitoring of greenhouse gas emission performance over time, we therefore recommend