Third IMO Greenhouse Gas Study 2014

Annex 7 265
Figure 41: First (upper chart) and second (lower chart) methodologies
to determine the number of ships per size category in 2050
From the emissions inventory, we know the following for each ship type for 2012:
1 the average size of ships per size category;
2 the distribution of ships over the size categories in terms of capacity; and
3 the distribution of ships over the size categories in terms of numbers.
Based on a literature review, we then argue how we expect the distribution of ships over the size categories (in
terms of capacity or in terms of numbers) to develop until 2050. Historical developments of the distribution,
expected structural changes in the markets and infrastructural constraints are taken into account. The average
size of a ship per ship type, which is necessary for the first methodology, then follows.
We are aware that the projection of the ship distribution until 2050 is associated with a high level of
uncertainty. Future structural changes and their impacts are difficult to assess, and some markets, such as the