Emissions budgets for shipping in a 2°C and a 4°C global warming scenario, and implications for operational efficiency

To achieve the widely accepted goal of keeping global temperature rise below 2°C above pre-industrial levels, greenhouse gas emissions must reduce drastically over the coming decades. Under this premise, the assumption that the shipping industry realises the same proportionate CO2 emission reductions as all other sectors on average has strong implications. This paper begins by considering an appropriate global CO2 emissions budget associated with a temperature rise of 2°C. Next, a range of future demand scenarios for international transport shipping are presented. Meeting the demand in any of the scenarios, while remaining within the emissions budget, requires stringent increases in overall operational efficiency. Different emissions and efficiency trajectories – with efficiency expressed in terms of the Energy Efficiency Operational Indicator (EEOI) – in line with the 2°C target are analysed. The potential short and long term levers of operational efficiency are explored.