Emission inventories

Emissions at the ship level are calculated based on energy consumption during voyages, which is converted to CO₂ emissions using fuel-specific emission factors. Energy demand is estimated from operational data like speed, distance, and fuel consumption, and then multiplied by the corresponding emission factor for the fuel used.

To understand emissions across different contexts, we aggregate emissions by ship type and year. This allows us to analyze the contribution of different ship types and track emissions over time. Aggregating the data also provides insights into the total emissions for the entire fleet, helping to identify areas for emission reductions. This method provides both detailed ship-level data and broader trends, enabling targeted actions to reduce emissions in specific ship categories or over particular periods.

Baseline 2018

Below, we can compare different ship segments. The comparison reveals a notable difference in emission intensity and distinct ship patterns. These differences highlight the varying environmental impacts of different ship types, which can inform strategies for reducing emissions in specific sectors of the shipping industry.

Whole fleet

To aggregate emissions at a global level, we combine data from the entire fleet to estimate the emissions for each sector. The results, shown below, represent the cumulative emissions for the whole shipping industry. With a total of around 80 thousand ships and more than 2 billion AIS points per year, the total emissions for the year 2019 amount to 1115 million tonnes of CO₂. This global estimate helps to quantify the environmental impact of the shipping sector, offering a comprehensive view of its contribution to overall emissions and highlighting areas where improvements can be made.

For more information, you can read the publication Kramel et al. (2021) “Global Shipping Emissions from a Well-to-Wake Perspective: The MariTEAM Model”.

Monthly emissions per ship type

Besides aggregating ship emissions spatially we can also attempt to aggregate them temporally by ship type. As we can see below, Nearly half of all emission stem from bulk carriers and container ships. We also can see the general increase in emissions during Noth Emisphere’s (where most shipping is concentrated)summer and the decrease over winter in the months of January and February.

Author: Diogo Kramel
Model: MariTeam model
Repository: GitHub
Data Version: v1.0.0 | 2025-02-13
Latest Update: March 24, 2025
Contact: diogo.kramel@ntnu.no