Greenhouse gas emission reduction targets for international shipping

The latest report of the Intergovernmental Panel on Climate Change suggests that in 2050 global greenhouse gas emissions need to be 40 to 70% below their 2010 levels in order to prevent a global temperature increase of more than 2°C compared to pre-industrial levels. However, the third greenhouse gas study of the International Maritime Organization projects shipping emissions to increase by 50 to 250% by 2050. This would result in an increase in the share in global emissions from the current level of 2 to 10% if the rest of the world is on a path towards the 2°C target. Taking into account that reducing emissions globally is more cost-effective when all sectors contribute and that shipping has significant technical and operational potential to reduce emissions, we analyze potential greenhouse gas mitigation targets for the shipping sector and the extent to which these targets can be achieved by efficiency improvements only. We conclude that all considered targets would require shipping emissions to stay well below the business-as-usual projections and that achieving these targets would, despite efficiency improvements, require instruments that aim at reducing the absolute emissions of the sector or at offsetting emissions by financing emission reductions in other sectors.