Third IMO Greenhouse Gas Study 2014

Executive Summary 21
Figure 15 shows the impact of market-driven or regulatory improvements in efficiency contrasted with
scenarios that have a larger share of LNG in the fuel mix. These four emissions projections are based on the
same transport demand projections. The two lower projections assume an efficiency improvement of 60%
instead of 40% over 2012 fleet average levels in 2050. The first and third projections have a 25% share of LNG
in the fuel mix in 2050 instead of 8%. Under these assumptions, improvements in efficiency have a larger
impact on emissions trajectories than changes in the fuel mix.
Figure 15: Projections of CO 2 emissions from international maritime transport under the
same demand projections. Larger improvements in efficiency have a higher impact on
CO 2 emissions than a larger share of LNG in the fuel mix
Table 5 shows the projection of the emissions of other substances. For each year, the median (minimum–
maximum) emissions are expressed as a share of their 2012 emissions. Most emissions increase in parallel with
CO 2 and fuel, with some notable exceptions. Methane emissions are projected to increase rapidly (albeit from
a very low base) as the share of LNG in the fuel mix increases. Emissions of sulphurous oxides, nitrogen oxides
and particulate matter increase at a lower rate than CO 2 emissions. This is driven by MARPOL Annex VI
requirements on the sulphur content of fuels (which also impact PM emissions) and the NO x technical code. In
scenarios that assume an increase in the share of fuel used in ECAs, the impact of these regulations is stronger.